FREESCALE SC9S12XS256J1VALR

MC9S12XS256
Reference Manual
Covers MC9S12XS Family
MC9S12XS256
MC9S12XS128
MC9S12XS64
HCS12
Microcontrollers
MC9S12XS256RMV1
Rev. 1.10
05/2010
freescale.com
To provide the most up-to-date information, the document revision on the World Wide Web is the most
current. A printed copy may be an earlier revision. To verify you have the latest information available, refer
to: http://freescale.com/
This document contains information for the complete S12XS Family and thus includes a set of separate
flash (FTMR) module sections to cover the whole family. A full list of family members and options is
included in the appendices.
This document contains information for all constituent modules, with the exception of the CPU. For CPU
information please refer to CPU12XV1 in the CPU12/CPU12X Reference Manual.
Revision History
Date
Revision
Level
May, 2009
1.08
Removed all KGD references
Corrected Detailed Register Map (FERSTAT)
Corrected statement on VDDA/VDDX protection diodes
September,
2009
1.09
Updated Chapter 8 S12XE Clocks and Reset Generator (S12XECRGV1)
Updated Chapter 14 Serial Communication Interface (S12SCIV5)
Updated Chapter 16 Timer Module (TIM16B8CV2)
Updated Chapter 18 256 KByte Flash Module (S12XFTMR256K1V1)
Updated Chapter 19 128 KByte Flash Module (S12XFTMR128K1V1)
Updated Chapter 20 64 KByte Flash Module (S12XFTMR64K1V1)
May, 2010
1.10
Updated Chapter 2 Port Integration Module (S12XSPIMV1)
Updated Chapter 16 Timer Module (TIM16B8CV2)
BDM Alternate clock source defined in device overview
Description
Chapter 1
Device Overview S12XS Family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Chapter 2
Port Integration Module (S12XSPIMV1) . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Chapter 3
Memory Mapping Control (S12XMMCV4) . . . . . . . . . . . . . . . . . . . . . . . .127
Chapter 4
Interrupt (S12XINTV2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151
Chapter 5
Background Debug Module (S12XBDMV2) . . . . . . . . . . . . . . . . . . . . . . .167
Chapter 6
S12X Debug (S12XDBGV3) Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . .193
Chapter 7
Security (S12XS9SECV2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .229
Chapter 8
S12XE Clocks and Reset Generator (S12XECRGV1) . . . . . . . . . . . . . . .235
Chapter 9
Pierce Oscillator (S12XOSCLCPV2) . . . . . . . . . . . . . . . . . . . . . . . . . . . .265
Chapter 10
Analog-to-Digital Converter (ADC12B16CV1) . . . . . . . . . . . . . . . . . . . . .269
Chapter 11
Freescale’s Scalable Controller Area Network (S12MSCANV3) . . . . . .295
Chapter 12
Periodic Interrupt Timer (S12PIT24B4CV1) . . . . . . . . . . . . . . . . . . . . . . .349
Chapter 13
Pulse-Width Modulator (S12PWM8B8CV1) . . . . . . . . . . . . . . . . . . . . . . .365
Chapter 14
Serial Communication Interface (S12SCIV5) . . . . . . . . . . . . . . . . . . . . . .397
Chapter 15
Serial Peripheral Interface (S12SPIV5) . . . . . . . . . . . . . . . . . . . . . . . . . . .435
Chapter 16
Timer Module (TIM16B8CV2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .461
Chapter 17
Voltage Regulator (S12VREGL3V3V1) . . . . . . . . . . . . . . . . . . . . . . . . . . .489
Chapter 18
256 KByte Flash Module (S12XFTMR256K1V1). . . . . . . . . . . . . . . . . . . .507
Chapter 19
128 KByte Flash Module (S12XFTMR128K1V1). . . . . . . . . . . . . . . . . . . .557
Chapter 20
64 KByte Flash Module (S12XFTMR64K1V1). . . . . . . . . . . . . . . . . . . . . .607
Appendix A
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .657
Appendix B
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .698
Appendix C
PCB Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .708
Appendix D
Derivative Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .712
Appendix E
Detailed Register Address Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .713
Appendix F
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .735
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
3
S12XS Family Reference Manual, Rev. 1.10
4
Freescale Semiconductor
Chapter 1
Device Overview S12XS Family
1.1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
1.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
1.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
1.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.1.4 Device Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.1.5 Address Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.1.6 Detailed Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.1.7 Part ID Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.2 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
1.2.1 Device Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
1.2.2 Pin Assignment Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
1.2.3 Detailed Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
1.2.4 Power Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
1.3 System Clock Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
1.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
1.4.1 Chip Configuration Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
1.4.2 Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
1.4.3 Freeze Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
1.5 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
1.6 Resets and Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
1.6.1 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
1.6.2 Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
1.6.3 Effects of Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
1.7 ATD0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
1.7.1 External Trigger Input Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
1.7.2 ATD0 Channel[17] Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
1.8 VREG Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
1.8.1 Temperature Sensor Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
1.9 BDM Clock Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
1.10 Oscillator Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Chapter 2
Port Integration Module (S12XSPIMV1)
2.1
2.2
2.3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
2.1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
2.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
5
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.3.6
2.3.7
2.3.8
2.3.9
2.3.10
2.3.11
2.3.12
2.3.13
2.3.14
2.3.15
2.3.16
2.3.17
2.3.18
2.3.19
2.3.20
2.3.21
2.3.22
2.3.23
2.3.24
2.3.25
2.3.26
2.3.27
2.3.28
2.3.29
2.3.30
2.3.31
2.3.32
2.3.33
2.3.34
2.3.35
2.3.36
2.3.37
2.3.38
2.3.39
2.3.40
2.3.41
2.3.42
2.3.43
2.3.44
2.3.45
Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Port A Data Register (PORTA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Port B Data Register (PORTB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Port A Data Direction Register (DDRA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Port B Data Direction Register (DDRB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
PIM Reserved Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Port E Data Register (PORTE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Port E Data Direction Register (DDRE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Ports ABEK, BKGD pin Pull-up Control Register (PUCR) . . . . . . . . . . . . . . . . . . . . . . 79
Ports ABEK Reduced Drive Register (RDRIV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
ECLK Control Register (ECLKCTL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
PIM Reserved Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
IRQ Control Register (IRQCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
PIM Reserved Register PIMTEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Port K Data Register (PORTK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Port K Data Direction Register (DDRK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Port T Data Register (PTT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Port T Input Register (PTIT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Port T Data Direction Register (DDRT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Port T Reduced Drive Register (RDRT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Port T Pull Device Enable Register (PERT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Port T Polarity Select Register (PPST) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
PIM Reserved Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Port T Routing Register (PTTRR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Port S Data Register (PTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Port S Input Register (PTIS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Port S Data Direction Register (DDRS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Port S Reduced Drive Register (RDRS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Port S Pull Device Enable Register (PERS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Port S Polarity Select Register (PPSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Port S Wired-Or Mode Register (WOMS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
PIM Reserved Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Port M Data Register (PTM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Port M Input Register (PTIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Port M Data Direction Register (DDRM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Port M Reduced Drive Register (RDRM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Port M Pull Device Enable Register (PERM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Port M Polarity Select Register (PPSM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Port M Wired-Or Mode Register (WOMM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Module Routing Register (MODRR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Port P Data Register (PTP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Port P Input Register (PTIP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Port P Data Direction Register (DDRP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Port P Reduced Drive Register (RDRP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
S12XS Family Reference Manual, Rev. 1.10
6
Freescale Semiconductor
2.4
2.5
2.3.46 Port P Pull Device Enable Register (PERP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
2.3.47 Port P Polarity Select Register (PPSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
2.3.48 Port P Interrupt Enable Register (PIEP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
2.3.49 Port P Interrupt Flag Register (PIFP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
2.3.50 Port H Data Register (PTH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
2.3.51 Port H Input Register (PTIH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
2.3.52 Port H Data Direction Register (DDRH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
2.3.53 Port H Reduced Drive Register (RDRH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
2.3.54 Port H Pull Device Enable Register (PERH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
2.3.55 Port H Polarity Select Register (PPSH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
2.3.56 Port H Interrupt Enable Register (PIEH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
2.3.57 Port H Interrupt Flag Register (PIFH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
2.3.58 Port J Data Register (PTJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
2.3.59 Port J Input Register (PTIJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
2.3.60 Port J Data Direction Register (DDRJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
2.3.61 Port J Reduced Drive Register (RDRJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
2.3.62 Port J Pull Device Enable Register (PERJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
2.3.63 Port J Polarity Select Register (PPSJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.3.64 Port J Interrupt Enable Register (PIEJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.3.65 Port J Interrupt Flag Register (PIFJ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
2.3.66 Port AD0 Data Register 0 (PT0AD0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
2.3.67 Port AD0 Data Register 1 (PT1AD0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
2.3.68 Port AD0 Data Direction Register 0 (DDR0AD0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
2.3.69 Port AD0 Data Direction Register 1 (DDR1AD0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
2.3.70 Port AD0 Reduced Drive Register 0 (RDR0AD0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
2.3.71 Port AD0 Reduced Drive Register 1 (RDR1AD0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
2.3.72 Port AD0 Pull Up Enable Register 0 (PER0AD0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
2.3.73 Port AD0 Pull Up Enable Register 1 (PER1AD0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
2.3.74 PIM Reserved Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
2.4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
2.4.2 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
2.4.3 Pins and Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
2.4.4 Pin interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Initialization Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
2.5.1 Port Data and Data Direction Register writes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Chapter 3
Memory Mapping Control (S12XMMCV4)
3.1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
3.1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
3.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
3.1.3 S12X Memory Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
3.1.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
3.1.5 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
7
3.2
3.3
3.4
3.5
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
3.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
3.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
3.4.1 MCU Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
3.4.2 Memory Map Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
3.4.3 Chip Bus Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
3.5.1 CALL and RTC Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Chapter 4
Interrupt (S12XINTV2)
4.1
4.2
4.3
4.4
4.5
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
4.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
4.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
4.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
4.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
4.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
4.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
4.4.1 S12X Exception Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
4.4.2 Interrupt Prioritization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
4.4.3 XGATE Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
4.4.4 Priority Decoders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
4.4.5 Reset Exception Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
4.4.6 Exception Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
4.5.1 Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
4.5.2 Interrupt Nesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
4.5.3 Wake Up from Stop or Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Chapter 5
Background Debug Module (S12XBDMV2)
5.1
5.2
5.3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
5.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
5.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
5.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
5.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
5.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
S12XS Family Reference Manual, Rev. 1.10
8
Freescale Semiconductor
5.4
5.3.3 Family ID Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
5.4.1 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
5.4.2 Enabling and Activating BDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
5.4.3 BDM Hardware Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
5.4.4 Standard BDM Firmware Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
5.4.5 BDM Command Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
5.4.6 BDM Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
5.4.7 Serial Interface Hardware Handshake Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
5.4.8 Hardware Handshake Abort Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
5.4.9 SYNC — Request Timed Reference Pulse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
5.4.10 Instruction Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
5.4.11 Serial Communication Time Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Chapter 6
S12X Debug (S12XDBGV3) Module
6.1
6.2
6.3
6.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
6.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
6.1.2 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
6.1.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
6.1.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
6.1.5 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
6.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
6.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
6.4.1 S12XDBG Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
6.4.2 Comparator Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
6.4.3 Trigger Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
6.4.4 State Sequence Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
6.4.5 Trace Buffer Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
6.4.6 Tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
6.4.7 Breakpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Chapter 7
Security (S12XS9SECV2)
7.1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
7.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
7.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
7.1.3 Securing the Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
7.1.4 Operation of the Secured Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
7.1.5 Unsecuring the Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
7.1.6 Reprogramming the Security Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
9
7.1.7 Complete Memory Erase (Special Modes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Chapter 8
S12XE Clocks and Reset Generator (S12XECRGV1)
8.1
8.2
8.3
8.4
8.5
8.6
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
8.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
8.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
8.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
8.2.1 VDDPLL, VSSPLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
8.2.2 RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
8.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
8.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
8.4.1 Functional Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
8.4.2 Operation Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
8.4.3 Low Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
8.5.1 Description of Reset Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
8.6.1 Description of Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
Chapter 9
Pierce Oscillator (S12XOSCLCPV2)
9.1
9.2
9.3
9.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
9.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
9.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
9.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
9.2.1 VDDPLL and VSSPLL — Operating and Ground Voltage Pins . . . . . . . . . . . . . . . . . . . . 266
9.2.2 EXTAL and XTAL — Input and Output Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
9.4.1 Gain Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
9.4.2 Clock Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
9.4.3 Wait Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
9.4.4 Stop Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
Chapter 10
Analog-to-Digital Converter (ADC12B16CV1)
10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
10.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
10.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
S12XS Family Reference Manual, Rev. 1.10
10
Freescale Semiconductor
10.2
10.3
10.4
10.5
10.6
10.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
10.2.1 Detailed Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
10.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
10.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
10.4.1 Analog Sub-Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
10.4.2 Digital Sub-Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
Chapter 11
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
11.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
11.1.2 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
11.1.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
11.1.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
11.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
11.2.1 RXCAN — CAN Receiver Input Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
11.2.2 TXCAN — CAN Transmitter Output Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
11.2.3 CAN System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
11.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
11.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
11.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
11.3.3 Programmer’s Model of Message Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
11.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331
11.4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331
11.4.2 Message Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331
11.4.3 Identifier Acceptance Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
11.4.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340
11.4.5 Low-Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
11.4.6 Reset Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
11.4.7 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
11.5 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
11.5.1 MSCAN initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
11.5.2 Bus-Off Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
Chapter 12
Periodic Interrupt Timer (S12PIT24B4CV1)
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
12.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
12.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
11
12.2
12.3
12.4
12.5
12.6
12.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
12.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
12.4.1 Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
12.4.2 Interrupt Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
12.4.3 Hardware Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
12.5.1 Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
12.5.2 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
12.5.3 Flag Clearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
Chapter 13
Pulse-Width Modulator (S12PWM8B8CV1)
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
13.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
13.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
13.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
13.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
13.2.1 PWM7 — PWM Channel 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.2.2 PWM6 — PWM Channel 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.2.3 PWM5 — PWM Channel 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.2.4 PWM4 — PWM Channel 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.2.5 PWM3 — PWM Channel 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.2.6 PWM3 — PWM Channel 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.2.7 PWM3 — PWM Channel 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.2.8 PWM3 — PWM Channel 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
13.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368
13.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
13.4.1 PWM Clock Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
13.4.2 PWM Channel Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
13.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
13.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
Chapter 14
Serial Communication Interface (S12SCIV5)
14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
14.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
14.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
14.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
S12XS Family Reference Manual, Rev. 1.10
12
Freescale Semiconductor
14.2
14.3
14.4
14.5
14.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
14.2.1 TXD — Transmit Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
14.2.2 RXD — Receive Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
14.3.1 Module Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
14.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
14.4.1 Infrared Interface Submodule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
14.4.2 LIN Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
14.4.3 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
14.4.4 Baud Rate Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
14.4.5 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
14.4.6 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
14.4.7 Single-Wire Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
14.4.8 Loop Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
14.5.1 Reset Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
14.5.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
14.5.3 Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
14.5.4 Recovery from Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
14.5.5 Recovery from Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
Chapter 15
Serial Peripheral Interface (S12SPIV5)
15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
15.1.1 Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
15.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
15.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
15.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436
15.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
15.2.1 MOSI — Master Out/Slave In Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
15.2.2 MISO — Master In/Slave Out Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
15.2.3 SS — Slave Select Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
15.2.4 SCK — Serial Clock Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
15.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
15.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
15.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
15.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
15.4.1 Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448
15.4.2 Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
15.4.3 Transmission Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
15.4.4 SPI Baud Rate Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455
15.4.5 Special Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
15.4.6 Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
13
15.4.7 Low Power Mode Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
Chapter 16
Timer Module (TIM16B8CV2)
16.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
16.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
16.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
16.1.3 Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
16.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465
16.2.1 IOC7 — Input Capture and Output Compare Channel 7 Pin . . . . . . . . . . . . . . . . . . . . 465
16.2.2 IOC6 — Input Capture and Output Compare Channel 6 Pin . . . . . . . . . . . . . . . . . . . . 465
16.2.3 IOC5 — Input Capture and Output Compare Channel 5 Pin . . . . . . . . . . . . . . . . . . . . 465
16.2.4 IOC4 — Input Capture and Output Compare Channel 4 Pin . . . . . . . . . . . . . . . . . . . . 465
16.2.5 IOC3 — Input Capture and Output Compare Channel 3 Pin . . . . . . . . . . . . . . . . . . . . 465
16.2.6 IOC2 — Input Capture and Output Compare Channel 2 Pin . . . . . . . . . . . . . . . . . . . . 465
16.2.7 IOC1 — Input Capture and Output Compare Channel 1 Pin . . . . . . . . . . . . . . . . . . . . 466
16.2.8 IOC0 — Input Capture and Output Compare Channel 0 Pin . . . . . . . . . . . . . . . . . . . . 466
16.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
16.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
16.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
16.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
16.4.1 Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484
16.4.2 Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
16.4.3 Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
16.4.4 Pulse Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
16.4.5 Event Counter Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
16.4.6 Gated Time Accumulation Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
16.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
16.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
16.6.1 Channel [7:0] Interrupt (C[7:0]F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488
16.6.2 Pulse Accumulator Input Interrupt (PAOVI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488
16.6.3 Pulse Accumulator Overflow Interrupt (PAOVF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488
16.6.4 Timer Overflow Interrupt (TOF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488
Chapter 17
Voltage Regulator (S12VREGL3V3V1)
17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
17.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
17.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
17.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490
17.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
17.2.1 VDDR — Regulator Power Input Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
17.2.2 VDDA, VSSA — Regulator Reference Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
17.2.3 VDD, VSS — Regulator Output1 (Core Logic) Pins . . . . . . . . . . . . . . . . . . . . . . . . . . 492
S12XS Family Reference Manual, Rev. 1.10
14
Freescale Semiconductor
17.2.4 VDDF — Regulator Output2 (NVM Logic) Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
17.2.5 VDDPLL, VSSPLL — Regulator Output3 (PLL) Pins . . . . . . . . . . . . . . . . . . . . . . . . . 493
17.2.6 VDDX — Power Input Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
17.2.7 VREGEN — Optional Regulator Enable Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
17.2.8 VREG_API — Optional Autonomous Periodical Interrupt Output Pin . . . . . . . . . . . . . . 493
17.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
17.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
17.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495
17.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
17.4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
17.4.2 Regulator Core (REG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
17.4.3 Low-Voltage Detect (LVD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
17.4.4 Power-On Reset (POR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
17.4.5 Low-Voltage Reset (LVR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
17.4.6 HTD - High Temperature Detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
17.4.7 Regulator Control (CTRL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
17.4.8 Autonomous Periodical Interrupt (API) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
17.4.9 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504
17.4.10Description of Reset Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504
17.4.11Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504
Chapter 18
256 KByte Flash Module (S12XFTMR256K1V1)
18.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
18.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508
18.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
18.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
18.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
18.3 Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
18.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
18.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
18.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
18.4.1 Flash Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
18.4.2 Flash Command Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540
18.4.3 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
18.4.4 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554
18.4.5 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554
18.5 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554
18.5.1 Unsecuring the MCU using Backdoor Key Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554
18.5.2 Unsecuring the MCU in Special Single Chip Mode using BDM . . . . . . . . . . . . . . . . . 555
18.5.3 Mode and Security Effects on Flash Command Availability . . . . . . . . . . . . . . . . . . . . . 556
18.6 Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
15
Chapter 19
128 KByte Flash Module (S12XFTMR128K1V1)
19.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557
19.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558
19.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559
19.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559
19.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 560
19.3 Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 560
19.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561
19.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564
19.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
19.4.1 Flash Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
19.4.2 Flash Command Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590
19.4.3 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
19.4.4 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
19.4.5 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
19.5 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
19.5.1 Unsecuring the MCU using Backdoor Key Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
19.5.2 Unsecuring the MCU in Special Single Chip Mode using BDM . . . . . . . . . . . . . . . . . 605
19.5.3 Mode and Security Effects on Flash Command Availability . . . . . . . . . . . . . . . . . . . . . 606
19.6 Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606
Chapter 20
64 KByte Flash Module (S12XFTMR64K1V1)
20.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
20.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608
20.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609
20.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
20.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
20.3 Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611
20.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611
20.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615
20.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635
20.4.1 Flash Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635
20.4.2 Flash Command Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 640
20.4.3 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653
20.4.4 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654
20.4.5 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654
20.5 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654
20.5.1 Unsecuring the MCU using Backdoor Key Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655
20.5.2 Unsecuring the MCU in Special Single Chip Mode using BDM . . . . . . . . . . . . . . . . . 655
20.5.3 Mode and Security Effects on Flash Command Availability . . . . . . . . . . . . . . . . . . . . . 656
20.6 Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
S12XS Family Reference Manual, Rev. 1.10
16
Freescale Semiconductor
Appendix A
Electrical Characteristics
A.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657
A.1.1 Parameter Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657
A.1.2 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657
A.1.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658
A.1.4 Current Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659
A.1.5 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659
A.1.6 ESD Protection and Latch-up Immunity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 660
A.1.7 Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 661
A.1.8 Power Dissipation and Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662
A.1.9 I/O Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666
A.1.10 Supply Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 669
A.2 ATD Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 673
A.2.1 ATD Operating Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 673
A.2.2 Factors Influencing Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 673
A.2.3 ATD Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 675
A.3 NVM, Flash. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 679
A.3.1 Timing Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 679
A.3.2 NVM Reliability Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 683
A.4 Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 685
A.5 Output Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686
A.5.1 Resistive Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686
A.5.2 Capacitive Loads. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686
A.5.3 Chip Power-up and Voltage Drops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686
A.6 Reset, Oscillator and PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 688
A.6.1 Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 688
A.6.2 Oscillator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 690
A.6.3 Phase Locked Loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
A.7 MSCAN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693
A.8 SPI Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694
A.8.1 Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694
A.8.2 Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 696
Appendix B
Package Information
B.1 112-pin LQFP Mechanical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 699
B.2 80-Pin QFP Mechanical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
B.3 64-Pin LQFP Mechanical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705
Appendix C
PCB Layout Guidelines
C.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708
C.1.1 112-Pin LQFP Recommended PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
17
C.1.2 80-Pin QFP Recommended PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710
C.1.3 64-Pin LQFP Recommended PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711
Appendix D
Derivative Differences
D.1 Memory Sizes and Package Options S12XS family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 712
Appendix E
Detailed Register Address Map
E.1
Detailed Register Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713
Appendix F
Ordering Information
F.1
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735
S12XS Family Reference Manual, Rev. 1.10
18
Freescale Semiconductor
Chapter 1
Device Overview S12XS Family
1.1
Introduction
The new S12XS family of 16-bit micro controllers is a compatible, reduced version of the S12XE family.
These families provide an easy approach to develop common platforms from low-end to high-end
applications, minimizing the redesign of software and hardware.
Targeted at generic automotive applications and CAN nodes, some typical examples of these applications
are: Body Controllers, Occupant Detection, Door Modules, RKE Receivers, Smart Actuators, Lighting
Modules and Smart Junction Boxes amongst many others.
The S12XS family retains many of the features of the S12XE family including Error Correction Code
(ECC) on Flash memory, a separate Data-Flash Module for code or data storage, a Frequency Modulated
Locked Loop (IPLL) that improves the EMC performance and a fast ATD converter.
S12XS family delivers 32-bit performance with all the advantages and efficiencies of a 16-bit MCU while
retaining the low cost, power consumption, EMC and code-size efficiency advantages currently enjoyed
by users of Freescale’s existing 16-bit S12 and S12X MCU families. Like members of other S12X
families, the S12XS family runs 16-bit wide accesses without wait states for all peripherals and memories.
The S12XS family is available in 112-pin LQFP, 80-pin QFP, 64-pin LQFP package options and maintains
a high level of pin compatibility with the S12XE family. In addition to the I/O ports available in each
module, up to 18 further I/O ports are available with interrupt capability allowing Wake-Up from stop or
wait modes.
The peripheral set includes MSCAN, SPI, two SCIs, an 8-channel 24-bit periodic interrupt timer, 8channel 16-bit Timer, 8-channel PWM and up to 16- channel 12-bit ATD converter.
Software controlled peripheral-to-port routing enables access to a flexible mix of the peripheral modules
in the lower pin count package options.
1.1.1
Features
Features of the S12XS Family are listed here. Please see Table D-1 for memory options and Table D-2 for
the peripheral features that are available on the different family members.
• 16-bit CPU12X
— Upward compatible with S12 instruction set with the exception of five Fuzzy instructions
(MEM, WAV, WAVR, REV, REVW) which have been removed
— Enhanced indexed addressing
— Access to large data segments independent of PPAGE
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
19
Device Overview S12XS Family
•
•
•
•
•
•
•
•
INT (interrupt module)
— Seven levels of nested interrupts
— Flexible assignment of interrupt sources to each interrupt level.
— External non-maskable high priority interrupt (XIRQ)
— The following inputs can act as Wake-up Interrupts
– IRQ and non-maskable XIRQ
– CAN receive pins
– SCI receive pins
– Depending on the package option up to 20 pins on ports J, H and P configurable as rising or
falling edge sensitive
MMC (module mapping control)
DBG (debug module)
— Monitoring of CPU bus with tag-type or force-type breakpoint requests
— 64 x 64-bit circular trace buffer captures change-of-flow or memory access information
BDM (background debug mode)
OSC_LCP (oscillator)
— Low power loop control Pierce oscillator utilizing a 4MHz to 16MHz crystal
— Good noise immunity
— Full-swing Pierce option utilizing a 2MHz to 40MHz crystal
— Transconductance sized for optimum start-up margin for typical crystals
IPLL (Internally filtered, frequency modulated phase-locked-loop clock generation)
— No external components required
— Configurable option to spread spectrum for reduced EMC radiation (frequency modulation)
CRG (clock and reset generation)
— COP watchdog
— Real time interrupt
— Clock monitor
— Fast wake up from STOP in self clock mode
Memory Options
— 64K, 128K and 256K byte Flash
— Flash General Features
– 64 data bits plus 8 syndrome ECC (Error Correction Code) bits allow single bit failure
correction and double fault detection
– Erase sector size 1024 bytes
– Automated program and erase algorithm
– Protection scheme to prevent accidental program or erase
– Security option to prevent unauthorized access
– Sense-amp margin level setting for reads
— 4K and 8K byte Data Flash space
S12XS Family Reference Manual, Rev. 1.10
20
Freescale Semiconductor
Device Overview S12XS Family
•
•
•
•
– 16 data bits plus 6 syndrome ECC (Error Correction Code) bits allow single bit failure
correction and double fault detection
– Erase sector size 256 bytes
– Automated program and erase algorithm
— 4K, 8K and 12K byte RAM
16-channel, 12-bit Analog-to-Digital converter
— 8/10/12 Bit resolution
— 3µs, 10-bit single conversion time
— Left or right justified result data
— External and internal conversion trigger capability
— Internal oscillator for conversion in Stop modes
— Wake from low power modes on analog comparison > or <= match
— Continuous conversion mode
— Multiplexer for 16 analog input channels
— Multiple channel scans
— Pins can also be used as digital I/O
MSCAN (1 M bit per second, CAN 2.0 A, B software compatible module)
— 1 Mbit per second, CAN 2.0 A, B software compatible module
– Standard and extended data frames
– 0 - 8 bytes data length
– Programmable bit rate up to 1 Mbps
— Five receive buffers with FIFO storage scheme
— Three transmit buffers with internal prioritization
— Flexible identifier acceptance filter programmable as:
– 2 x 32-bit
– 4 x 16-bit
– 8 x 8-bit
— Wake-up with integrated low pass filter option
— Loop back for self test
— Listen-only mode to monitor CAN bus
— Bus-off recovery by software intervention or automatically
— 16-bit time stamp of transmitted/received messages
TIM (standard timer module)
— 8 x 16-bit channels for input capture or output compare
— 16-bit free-running counter with 8-bit precision prescaler
— 1 x 16-bit pulse accumulator
PIT (periodic interrupt timer)
— Up to four timers with independent time-out periods
— Time-out periods selectable between 1 and 224 bus clock cycles
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
21
Device Overview S12XS Family
•
•
•
•
•
•
•
— Time-out interrupt and peripheral triggers
— Start of timers can be aligned
Up to 8 channel x 8-bit or 4 channel x 16-bit Pulse Width Modulator
— Programmable period and duty cycle per channel
— Center- or left-aligned outputs
— Programmable clock select logic with a wide range of frequencies
Serial Peripheral Interface Module (SPI)
— Configurable for 8 or 16-bit data size
— Full-duplex or single-wire bidirectional
— Double-buffered transmit and receive
— Master or Slave mode
— MSB-first or LSB-first shifting
— Serial clock phase and polarity options
Two Serial Communication Interfaces (SCI)
— Full-duplex or single wire operation
— Standard mark/space non-return-to-zero (NRZ) format
— Selectable IrDA 1.4 return-to-zero-inverted (RZI) format with programmable pulse widths
— 13-bit baud rate selection
— Programmable character length
— Programmable polarity for transmitter and receiver
— Receive wakeup on active edge
— Break detect and transmit collision detect supporting LIN
On-Chip Voltage Regulator
— Two parallel, linear voltage regulators with bandgap reference
— Low-voltage detect (LVD) with low-voltage interrupt (LVI)
— Power-on reset (POR) circuit
— Low-voltage reset (LVR)
Low-power wake-up timer (API)
— Internal oscillator driving a down counter
— Trimmable to +/-10% accuracy
— Time-out periods range from 0.2ms to ~13s with a 0.2ms resolution
Input/Output
— Up to 91 general-purpose input/output (I/O) pins depending on the package option and 2 inputonly pins
— Hysteresis and configurable pull up/pull down device on all input pins
— Configurable drive strength on all output pins
Package Options
— 112-pin low-profile quad flat-pack (LQFP)
— 80-pin quad flat-pack (QFP)
S12XS Family Reference Manual, Rev. 1.10
22
Freescale Semiconductor
Device Overview S12XS Family
•
1.1.2
— 64-pin low-profile quad flat-pack (LQFP)
Operating Conditions
— Wide single Supply Voltage range 3.135 V to 5.5 V at full performance
– Separate supply for internal voltage regulator and I/O allow optimized EMC filtering
— 40MHz maximum CPU bus frequency
— Ambient temperature range –40°C to 125°C
— Temperature Options:
– –40°C to 85°C
– –40°C to 105°C
– –40°C to 125°C
Modes of Operation
Operating modes:
• Normal single-chip mode
• Special single-chip mode with active background debug mode
NOTE
This chip family does not support external bus modes.
Low-power modes:
• System stop modes
— Pseudo stop mode
— Full stop mode with fast wake-up option
• System wait mode
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
23
Device Overview S12XS Family
1.1.3
Block Diagram
Figure 1-1 shows a block diagram of the S12XS Family devices
CPU12X
BKGD
EXTAL
XTAL
Debug Module
Single-wire Background 4 address breakpoints
Debug Module
2 data breakpoints
512 Byte Trace Buffer
Amplitude Controlled
Low Power Pierce or
Full drive Pierce
Oscillator
PLL with Frequency
Modulation option
RESET
TEST
PTE
XIRQ
IRQ
PTA
PB[7:0]
PK[7,5:0]
PIT
4ch 24-bit Timer
Multilevel
Interrupt Module
CAN0
msCAN 2.0B
SCI0
Asynchronous Serial IF
SCI1
Asynchronous Serial IF
SPI0
Synchronous Serial IF
PTK
PA[7:0]
8-bit 8 channel
Pulse Width Modulator
PWM0
PWM1
PWM2
PWM3
PWM4
PWM5
PWM6
PWM7
PT0
PT1
PT2
PT3
PT4
PT5
PT6
PT7
PP0
PP1
PP2
PP3
PP4
PP5
PP6
PP7
PM0
PM1
PM2
PM3
PM4
PM5
PM6
PM7
PS0
PS1
PS2
PS3
PS4
PS5
PS6
PS7
PH0
PH1
PH2
PH3
PH4
PH5
PH6
PH7
PJ0
PJ1
RXCAN
TXCAN
ECLK
XCLKS/ECLKX2
PTB
PE0
PE1
PE2
PE3
PE4
PE5
PE6
PE7
Reset Generation
and Test Entry
Clock Monitor
COP Watchdog
Periodic Interrupt
Async. Periodic Int.
PWM
PTT
16-bit 8 channel
Timer
IOC0
IOC1
IOC2
IOC3
IOC4
IOC5
IOC6
IOC7
PTP (Wake-Up Int)
TIM
RXD
TXD
RXD
TXD
MISO
MOSI
SCK
SS
PAD[15:0]
PTM
Voltage Regulator
AN[15:0]
PTS
4K … 8K bytes Data Flash
VDDR
VDD
VDDF
VDDPLL
PTAD
8/10/12-bit 16-channel
Analog-Digital Converter
PTH (Wake-up Int)
4K … 12K bytes RAM
VDDA
VSSA
VRH
VRL
ATD
PTJ (Wake-up Int)
64K … 256K bytes Flash
PJ6
PJ7
Figure 1-1. S12XS Family Block Diagram
S12XS Family Reference Manual, Rev. 1.10
24
Freescale Semiconductor
Device Overview S12XS Family
1.1.4
Device Memory Map
Table 1-1 shows the device register memory map.
Table 1-1. Device Register Memory Map
Address
Module
Size
(Bytes)
0x0000–0x0009
PIM (port integration module)
10
0x000A–0x000B
MMC (memory map control)
2
0x000C–0x000D
PIM (port integration module)
2
0x000E–0x000F
Reserved
2
0x0010–0x0017
MMC (memory map control)
8
0x0018–0x0019
Reserved
2
0x001A–0x001B
Device ID register
2
0x001C–0x001F
PIM (port integration module)
4
0x0020–0x002F
DBG (debug module)
16
0x0030–0x0031
Reserved
2
0x0032–0x0033
PIM (port integration module)
2
0x0034–0x003F
ECRG (clock and reset generator)
12
0x0040–0x006F
TIM (timer module)
48
0x0070–0x00C7
Reserved
88
0x00C8–0x00CF
SCI0 (serial communications interface)
8
0x00D0–0x00D7
SCI1 (serial communications interface)
8
0x00D8–0x00DF
SPI0 (serial peripheral interface)
8
0x00E0–0x00FF
Reserved
32
0x0100–0x0113
FTMR control registers
20
0x0114–0x011F
Reserved
12
0x0120–0x012F
INT (interrupt module)
16
0x0130–0x013F
Reserved
16
0x0140–0x017F
CAN0
64
0x0180–0x023F
Reserved
192
0x0240–0x027F
PIM (port integration module)
64
0x0280–0x02BF
Reserved
64
0x02C0–0x02EF
ATD0 (analog-to-digital converter 12 bit 16-channel)
48
0x02F0–0x02F7
Voltage regulator
8
0x02F8–0x02FF
Reserved
8
0x0300–0x0327
PWM (pulse-width modulator 8 channels)
40
0x0328–0x033F
Reserved
24
0x0340–0x0367
PIT (periodic interrupt timer)
40
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
25
Device Overview S12XS Family
Table 1-1. Device Register Memory Map (continued)
Address
0x0368–0x07FF
Module
Reserved
Size
(Bytes)
1176
NOTE
Reserved register space shown in Table 1-1 is not allocated to any module.
This register space is reserved for future use. Writing to these locations has
no effect. Read access to these locations returns zero.
1.1.5
Address Mapping
Figure 1-2 shows S12XS CPU and BDM local address translation to the global memory map. It indicates
also the location of the internal resources in the memory map.
S12XS Family Reference Manual, Rev. 1.10
26
Freescale Semiconductor
Device Overview S12XS Family
CPU and BDM
Local Memory Map
Global Memory Map
0x00_0000
0x00_07FF
2K REGISTERS
Unimplemented
RAM
0x0000
0x0800
0x0C00
RAM
2K REGISTERS
1K DFLASH window
EPAGE
RAMSIZE
RAM_LOW
0x0F_FFFF
Reserved
DFLASH
0x1000
RPAGE
4K RAM window
DF_HIGH
0x2000
DFLASH
Resources
8K RAM
0x4000
0x13_FFFF
Unpaged
16K FLASH
Unimplemented
Space
0x8000
16K FLASH window
PPAGE
0x3F_FFFF
Unimplemented
FLASH
0xC000
Unpaged
16K FLASH
Vectors
FLASH_LOW
FLASH
FLASHSIZE
0xFFFF
0x7F_FFFF
Figure 1-2. S12XS Family Global Memory Map
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
27
Device Overview S12XS Family
Accessing the reserved area in the range of 0x0C00 to 0x0FFF will return undefined data values.
A CPU access to any unimplemented space causes an illegal address reset.
The range between 0x10_0000 and 0x13_FFFF is mapped to DFLASH (Data Flash). The DFLASH block
sizes are listed in Table 1-2.
Table 1-2. Derivative Dependent Memory Parameters of Device Internal Resources
Device
FLASH_LOW
SIZE/
PPAGE1
RAM_LOW
SIZE/
RPAGE2
DF_HIGH
SIZE/
EPAGE3
S12XS256
0x7C_0000
256K / 16
0x0F_D000
12K / 3
0x10_1FFF
8K / 8
S12XS128
0x7E_0000
128K / 8
0x0F_E000
8K / 2
0x10_1FFF
8K / 8
S12XS64
0x7F_0000
64K / 4
0x0F_F000
Number
of
16K
pages
addressable
via
PPAGE
register
1
2 Number of 4K pages addressing the RAM.
3 Number of 1K pages addressing the DFLASH
4K / 1
0x10_0FFF
4K / 4
1.1.6
Detailed Register Map
The detailed register map is listed in the appendix of the reference manual.
1.1.7
Part ID Assignments
The part ID is located in two 8-bit registers PARTIDH and PARTIDL (addresses 0x001A and 0x001B).
The read-only value is a unique part ID for each revision of the chip. Table 1-3 shows the assigned part ID
number and Mask Set number.
The Version ID is a word located in a flash information row at 0x40_00E8. The version ID number
indicates a specific version of internal NVM variables used to patch NVM errata. The default is no patch
(0xFFFF).
Table 1-3. Assigned Part ID Numbers
Device
Mask Set Number
Part ID1
Version ID
MC9S12XS256
0M05M
$C0C0
0xFFFF
MC9S12XS128
0M04M
$C1C0
0xFFFF
1M04M
$C1C1
0xFFFF
0M04M
$C1C0
0xFFFF
MC9S12XS64
1
1M04M
$C1C1
The coding is as follows:
Bit 15-12: Major family identifier
Bit 11-6: Minor family identifier
Bit 5-4: Major mask set revision number including FAB transfers
Bit 3-0: Minor — non full — mask set revision
0xFFFF
S12XS Family Reference Manual, Rev. 1.10
28
Freescale Semiconductor
Device Overview S12XS Family
1.2
Signal Description
This section describes signals that connect off-chip. It includes a pinout diagram, a table of signal
properties, and detailed discussion of signals. It is built from the signal description sections of the
individual IP blocks on the device.
1.2.1
Device Pinout
The XS family of devices offers pin-compatible packaged devices to assist with system development and
accommodate expansion of the application.
The S12XS family devices are offered in the following package options:
• 112-pin LQFP
• 80-pin QFP
• 64-pin LQFP
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
29
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
S12XS Family
112LQFP
Pins shown in BOLD are not
available on the 80 QFP
package
VRH
VDDA
PAD15/AN15
PAD07/AN07
PAD14/AN14
PAD06/AN06
PAD13/AN13
PAD05/AN05
PAD12/AN12
PAD04/AN04
PAD11/AN11
PAD03/AN03
PAD10/AN10
PAD02/AN02
PAD09/AN09
PAD01/AN01
PAD08/AN08
PAD00/AN00
VSS2
VDD
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
PB5
PB6
PB7
KWH7/PH7
KWH6/PH6
KWH5/PH5
KWH4/PH4
XCLKS/ECLKX2/PE7
PE6
PE5
ECLK/PE4
VSSX2
VDDX2
RESET
VDDR
VSS3
VSSPLL
EXTAL
XTAL
VDDPLL
KWH3/PH3
KWH2/PH2
KWH1/PH1
KWH0/PH0
PE3
PE2
IRQ/PE1
XIRQ/PE0
PWM3/KWP3/PP3
TXD1/IOC2/PWM2/KWP2/PP2
IOC1/PWM1/KWP1/PP1
RXD1/IOC0/PWM0/KWP0/PP0
PK3
PK2
PK1
PK0
IOC0/PT0
IOC1/PT1
IOC2/PT2
IOC3/PT3
VDDF
VSS1
PWM4/IOC4/PT4
VREG_API/PWM5/IOC5/PT5
PWM6/IOC6/PT6
PWM7/IOC7/PT7
PK5
PK4
KWJ1/PJ1
KWJ0/PJ0
MODC/BKGD
PB0
PB1
PB2
PB3
PB4
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
PP4/KWP4/PWM4
PP5/KPW5/PWM5
PP6/KWP6/PWM6
PP7/KWP7/PWM7
PK7
VDDX1
VSSX1
PM0/RXCAN0/RXD1
PM1/TXCAN0/TXD1
PM2/MISO0
PM3/SS0
PM4/MOSI0
PM5/SCK0
PJ6/KWJ6
PJ7/KWJ7
TEST
PS7/SS0
PS6/SCK0
PS5/MOSI0
PS4/MISO0
PS3/TXD1
PS2/RXD1
PS1/TXD0
PS0/RXD0
PM6
PM7
VSSA
VRL
Device Overview S12XS Family
Figure 1-3. S12XS Family Pin Assignments 112-pin LQFP Package
S12XS Family Reference Manual, Rev. 1.10
30
Freescale Semiconductor
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
PP4/KWP4/PWM4
PP5/KPW5/PWM5
PP7/KPW7/PWM7
VDDX1
VSSX1
PM0/RXCAN0/RXD1
PM1/TXCAN0/TXD1
PM2/MISO0
PM3/SS0
PM4/MOSI0
PM5/SCK0
PJ6/KWJ6
PJ7/KWJ7
TEST
PS3/TXD1
PS2/RXD1
PS1/TXD0
PS0/RXD0
VSSA
VRL
Device Overview S12XS Family
S12XS Family
80QFP
Pins shown in BOLD are
not available on the 64
QFP package
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
VRH
VDDA
PAD07/AN07
PAD06/AN06
PAD05/AN05
PAD04/AN04
PAD03/AN03
PAD02/AN02
PAD01/AN01
PAD00/AN00
VSS2
VDD
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PB5
PB6
PB7
XCLKS/ECLKX2/PE7
PE6
PE5
ECLK/PE5
VSSX2
VDDX2
RESET
VDDR
VSS3
VSSPLL
EXTAL
XTAL
VDDPLL
PE3
PE2
IRQ/PE1
XIRQ/PE0
PWM3/KWP3/PP3
TXD1/IOC2/PWM2/KWP2/PP2
IOC1/PWM1/KWP1/PP1
RXD1/IOC0/PWM0/KWP0/PP0
IOC0/PT0
IOC1/PT1
IOC2/PT2
IOC3/PT3
VDDF
VSS1
PWM4/IOC4/PT4
VREG_API/PWM5/IOC5/PT5
PWM6/IOC6/PT6
PWM7/IOC7/PT7
MODC/BKGD
PB0
PB1
PB2
PB3
PB4
Figure 1-4. S12XS Family Pin Assignments 80-pin QFP Package
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
31
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
PP5/KPW5/PWM5
PP7/KWP7/PWM7
VDDX1
VSSX1
PM0/RXCAN0/RXD1
PM1/TXCAN0/TXD1
PM2/MISO0
PM3/SS0
PM4/MOSI0
PM5/SCK0
TEST
PS3/TXD1
PS2/RXD1
PS1/TXD0
PS0/RXD0
VSSA/VRL
Device Overview S12XS Family
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
S12XS Family
64LQFP
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
VRH
VDDA
PAD07/AN07
PAD06/AN06
PAD05/AN05
PAD04/AN04
PAD03/AN03
PAD02/AN02
PAD01/AN01
PAD00/AN00
VSS2
VDD
PA3
PA2
PA1
PA0
PB5
PB6
PB7
XCLKS/ECLKX2/PE7
ECLK/PE4
VSSX2
VDDX2
RESET
VDDR
VSS3
VSSPLL
EXTAL
XTAL
VDDPLL
IRQ/PE1
XIRQ/PE0
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
PWM3/KWP3/PP3
TXD1/IOC2/PWM2/KWP2/PP2
IOC1/PWM1/KWP1/PP1
RXD1/IOC0/PWM0/KWP0/PP0
IOC0/PT0
IOC1/PT1
IOC2/PT2
IOC3/PT3
VDDF
VSS1
PWM4/IOC4/PT4
VREG_API/PWM5/IOC5/PT5
PWM6/IOC6/PT6
PWM7/IOC7/PT7
MODC/BKGD
PB0
Figure 1-5. S12XS Family Pin Assignments 64-pin LQFP Package
S12XS Family Reference Manual, Rev. 1.10
32
Freescale Semiconductor
Device Overview S12XS Family
1.2.2
Pin Assignment Overview
Table 1-4 provides a summary of which ports are available for each package option. Routing of pin
functions is summarized in Table 1-5.
Table 1-4. Port Availability by Package Option
Port
112 LQFP
80 QFP
64 LQFP
Port AD/ADC Channels
16/16
8/8
8/8
Port A pins
8
8
4
Port B pins
8
8
4
Port E pins inc. IRQ/XIRQ input only
8
8
4
Port H
8
0
0
Port J
4
2
0
Port K
7
0
0
Port M
8
6
6
Port P
8
7
6
Port S
8
4
4
Port T
8
8
8
Sum of Ports
91
59
44
I/O Power Pairs VDDX/VSSX
2/2
2/2
2/2
Table 1-5. Peripheral - Port Routing Options1
SCI1
PM[1:0]
PWM
O
O
PP[2:0]
O
PP[7:4]
PS[3:2]
PS[7:4]
TIM
O
PM[5:2]
PP[2,0]
SPI0
X
X
X
PT[2:0]
X
PT[7:4]
O
“X”
denotes
reset
condition,
“O”
denotes
a
possible
rerouting
1
under software control
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
33
Table 1-6. Pin-Out Summary1
Package Terminal
S12XS Family Reference Manual, Rev. 1.10
LQFP
112
QFP
80
LQFP
64
1
1
2
Function
Pin
2nd
Func.
3rd
Func.
4th
Func.
5th
Func.
1
PP3
KWP3
PWM3
—
—
2
2
PP2
KWP2
PWM2
IOC2
3
3
3
PP1
KWP1
PWM1
4
4
4
PP0
KWP0
5
-
-
PK3
6
-
-
7
-
8
Power
Supply
Internal Pull
Resistor
Description
Freescale Semiconductor
CTRL
Reset
State
VDDX
PERP/PPSP
Disabled
Port P I/O, interrupt,
PWM channel
TXD1
VDDX
PERP/PPSP
Disabled
Port P I/O, interrupt,
PWM/TIM channel, TXD
of SCI1
IOC1
—
VDDX
PERP/PPSP
Disabled
Port P I/O, interrupt,
PWM/TIM channel
PWM0
IOC0
RXD1
VDDX
PERP/PPSP
Disabled
Port P I/O, interrupt,
PWM/TIM channel,
RXD of SCI1
—
—
—
—
VDDX
PUCR
Up
Port K I/O
PK2
—
—
—
—
VDDX
PUCR
Up
Port K I/O
-
PK1
—
—
—
—
VDDX
PUCR
Up
Port K I/O
-
-
PK0
—
—
—
—
VDDX
PUCR
Up
Port K I/O
9
5
5
PT0
IOC0
—
—
—
VDDX
PERT/PPST
Disabled
Port T I/O, TIM channel
10
6
6
PT1
IOC1
—
—
—
VDDX
PERT/PPST
Disabled
Port T I/O, TIM channel
11
7
7
PT2
IOC2
—
—
—
VDDX
PERT/PPST
Disabled
Port T I/O, TIM channel
12
8
8
PT3
IOC3
—
—
—
VDDX
PERT/PPST
Disabled
Port T I/O, TIM channel
13
9
9
VDDF
—
—
—
—
—
—
—
—
14
10
10
VSS1
—
—
—
—
—
—
—
—
15
11
11
PT4
IOC4
PWM4
—
—
VDDX
PERT/PPST
Disabled
Port T I/O, PWM/TIM
channel
Device Overview S12XS Family
34
Table 1-6 provides a pin out summary listing the availability and functionality of individual pins for each package option.
Freescale Semiconductor
Table 1-6. Pin-Out Summary1 (continued)
Package Terminal
LQFP
112
QFP
80
LQFP
64
16
12
17
Function
S12XS Family Reference Manual, Rev. 1.10
Pin
2nd
Func.
3rd
Func.
4th
Func.
5th
Func.
12
PT5
IOC5
PWM5
VREG_
API
—
13
13
PT6
IOC6
PWM6
—
18
14
14
PT7
IOC7
PWM7
19
-
-
PK5
—
20
-
-
PK4
21
-
-
22
-
23
Power
Supply
Internal Pull
Resistor
Description
VDDX
PERT/PPST
Disabled
Port T I/O, PWM/TIM
channel, API output
—
VDDX
PERT/PPST
Disabled
Port T I/O, channel of
PWM/TIM
—
—
VDDX
PERT/PPST
Disabled
Port T I/O, channel of
PWM/TIM
—
—
—
VDDX
PUCR
Up
Port K I/O
—
—
—
—
VDDX
PUCR
Up
Port K I/O
PJ1
KWJ1
—
—
—
VDDX
PERJ/PPSJ
Up
Port J I/O, interrupt
-
PJ0
KWJ0
—
—
—
VDDX
PERJ/PPSJ
Up
Port J I/O, interrupt
15
15
BKGD
MODC
—
—
—
VDDX
Always on
Up
Background debug
24
16
16
PB0
—
—
—
—
VDDX
PUCR
Disabled
Port B I/O
25
17
-
PB1
—
—
—
—
VDDX
PUCR
Disabled
Port B I/O
26
18
-
PB2
—
—
—
—
VDDX
PUCR
Disabled
Port B I/O
27
19
-
PB3
—
—
—
—
VDDX
PUCR
Disabled
Port B I/O
28
20
-
PB4
—
—
—
—
VDDX
PUCR
Disabled
Port B I/O
29
21
17
PB5
—
—
—
—
VDDX
PUCR
Disabled
Port B I/O
30
22
18
PB6
—
—
—
—
VDDX
PUCR
Disabled
Port B I/O
31
23
19
PB7
—
—
—
—
VDDX
PUCR
Disabled
Port B I/O
32
-
-
PH7
KWH7
—
—
—
VDDX
PERH/PPSH
Disabled
Port H I/O, interrupt
33
-
-
PH6
KWH6
—
—
—
VDDX
PERH/PPSH
Disabled
Port H I/O, interrupt
34
-
-
PH5
KWH5
—
—
—
VDDX
PERH/PPSH
Disabled
Port H I/O, interrupt
35
-
-
PH4
KWH4
—
—
—
VDDX
PERH/PPSH
Disabled
Port H I/O, interrupt
35
Device Overview S12XS Family
CTRL
Reset
State
Package Terminal
LQFP
112
QFP
80
LQFP
64
36
24
37
Function
S12XS Family Reference Manual, Rev. 1.10
Pin
2nd
Func.
3rd
Func.
4th
Func.
5th
Func.
20
PE7
XCLKS
ECLKX2
—
—
25
-
PE6
—
—
—
38
26
-
PE5
—
—
39
27
21
PE4
ECLK
40
28
22
VSSX2
41
29
23
42
30
43
Power
Supply
Internal Pull
Resistor
Description
Freescale Semiconductor
CTRL
Reset
State
VDDX
PUCR
Up
—
VDDX
While RESET pin
is low: down2
Port E I/O
—
—
VDDX
While RESET pin
is low: down2
Port E I/O
—
—
—
VDDX
PUCR
Up
Port E I/O, bus clock
output
—
—
—
—
—
—
—
—
VDDX2
—
—
—
—
—
—
—
—
24
RESET
—
—
—
—
VDDX
31
25
VDDR
—
—
—
—
—
—
—
—
44
32
26
VSS3
—
—
—
—
—
—
—
—
45
33
27
VSSPLL
—
—
—
—
—
—
—
—
46
34
28
EXTAL
—
—
—
—
VDDPLL
NA
NA
Oscillator pin
47
35
29
XTAL
—
—
—
—
VDDPLL
NA
NA
Oscillator pin
48
36
30
VDDPLL
—
—
—
—
—
—
—
—
49
-
-
PH3
KWH3
—
—
—
VDDX
PERH/PPSH
Disabled
Port H I/O, interrupt
50
-
-
PH2
KWH2
—
—
—
VDDX
PERH/PPSH
Disabled
Port H I/O, interrupt
51
-
-
PH1
KWH1
—
—
—
VDDX
PERH/PPSH
Disabled
Port H I/O, interrupt
52
-
-
PH0
KWH0
—
—
—
VDDX
PERH/PPSH
Disabled
Port H I/O, interrupt
53
37
-
PE3
—
—
—
—
VDDX
PUCR
Up
Port E I/O
54
38
-
PE2
—
—
—
—
VDDX
PUCR
Up
Port E I/O
PULLUP
Port E I/O, system clock
output, clock select
input
External reset
Device Overview S12XS Family
36
Table 1-6. Pin-Out Summary1 (continued)
Freescale Semiconductor
Table 1-6. Pin-Out Summary1 (continued)
Package Terminal
LQFP
112
QFP
80
LQFP
64
55
39
56
Function
S12XS Family Reference Manual, Rev. 1.10
Pin
2nd
Func.
3rd
Func.
4th
Func.
5th
Func.
31
PE1
IRQ
—
—
—
40
32
PE0
XIRQ
—
—
57
41
33
PA0
—
—
58
42
34
PA1
—
59
43
35
PA2
60
44
36
61
45
62
Power
Supply
Internal Pull
Resistor
Description
VDDX
PUCR
Up
Port E Input, maskable
interrupt
—
VDDX
PUCR
Up
Port E Input, nonmaskable interrupt
—
—
VDDX
PUCR
Disabled
Port A I/O
—
—
—
VDDX
PUCR
Disabled
Port A I/O
—
—
—
—
VDDX
PUCR
Disabled
Port A I/O
PA3
—
—
—
—
VDDX
PUCR
Disabled
Port A I/O
-
PA4
—
—
—
—
VDDX
PUCR
Disabled
Port A I/O
46
-
PA5
—
—
—
—
VDDX
PUCR
Disabled
Port A I/O
63
47
-
PA6
—
—
—
—
VDDX
PUCR
Disabled
Port A I/O
64
48
-
PA7
—
—
—
—
VDDX
PUCR
Disabled
Port A I/O
65
49
37
VDD
—
—
—
—
—
—
—
—
66
50
38
VSS2
—
—
—
—
—
—
—
—
67
51
39
PAD00
AN00
—
—
—
VDDA
PER1AD
Disabled
Port AD I/O,
analog input of ATD
68
-
-
PAD08
AN08
—
—
—
VDDA
PER0AD
Disabled
Port AD I/O,
analog input of ATD
69
52
40
PAD01
AN01
—
—
—
VDDA
PER1AD
Disabled
Port AD I/O,
analog input of ATD
70
-
-
PAD09
AN09
—
—
—
VDDA
PER0AD
Disabled
Port AD I/O,
analog input of ATD
71
53
41
PAD02
AN02
—
—
—
VDDA
PER1AD
Disabled
Port AD I/O,
analog input of ATD
37
Device Overview S12XS Family
CTRL
Reset
State
Package Terminal
LQFP
112
QFP
80
LQFP
64
72
-
73
Function
S12XS Family Reference Manual, Rev. 1.10
Pin
2nd
Func.
3rd
Func.
4th
Func.
5th
Func.
-
PAD10
AN10
—
—
—
54
42
PAD03
AN03
—
—
74
-
-
PAD11
AN11
—
75
55
43
PAD04
AN04
76
-
-
PAD12
77
56
44
78
-
79
Power
Supply
Internal Pull
Resistor
Description
Freescale Semiconductor
CTRL
Reset
State
VDDA
PER0AD
Disabled
Port AD I/O,
analog input of ATD
—
VDDA
PER1AD
Disabled
Port AD I/O,
analog input of ATD
—
—
VDDA
PER0AD
Disabled
Port AD I/O,
analog input of ATD
—
—
—
VDDA
PER1AD
Disabled
Port AD I/O,
analog input of ATD
AN12
—
—
—
VDDA
PER0AD
Disabled
Port AD I/O,
analog input of ATD
PAD05
AN05
—
—
—
VDDA
PER1AD
Disabled
Port AD I/O,
analog input of ATD
-
PAD13
AN13
—
—
—
VDDA
PER0AD
Disabled
Port AD I/O,
analog input of ATD
57
45
PAD06
AN06
—
—
—
VDDA
PER1AD
Disabled
Port AD I/O,
analog input of ATD
80
-
-
PAD14
AN14
—
—
—
VDDA
PER0AD
Disabled
Port AD I/O,
analog input of ATD
81
58
46
PAD07
AN07
—
—
—
VDDA
PER1AD
Disabled
Port AD I/O,
analog input of ATD
82
-
-
PAD15
AN15
—
—
—
VDDA
PER0AD
Disabled
Port AD I/O,
analog input of ATD
83
59
47
VDDA
—
—
—
—
—
—
—
—
84
60
48
VRH
—
—
—
—
—
—
—
—
85
61
49
VRL3
—
—
—
—
—
—
—
—
86
62
49
VSSA
—
—
—
—
—
—
—
—
Device Overview S12XS Family
38
Table 1-6. Pin-Out Summary1 (continued)
Freescale Semiconductor
Table 1-6. Pin-Out Summary1 (continued)
Package Terminal
LQFP
112
QFP
80
LQFP
64
87
-
88
Function
S12XS Family Reference Manual, Rev. 1.10
Pin
2nd
Func.
3rd
Func.
4th
Func.
5th
Func.
-
PM7
—
—
—
—
-
-
PM6
—
—
—
89
63
50
PS0
RXD0
—
90
64
51
PS1
TXD0
91
65
52
PS2
92
66
53
93
-
94
Power
Supply
Internal Pull
Resistor
Description
CTRL
Reset
State
VDDX
PERM/PPSM
Disabled
Port M I/O
—
VDDX
PERM/PPSM
Disabled
Port M I/O
—
—
VDDX
PERS/PPSS
Up
Port S I/O, RXD of SCI0
—
—
—
VDDX
PERS/PPSS
Up
Port S I/O, TXD of SCI0
RXD1
—
—
—
VDDX
PERS/PPSS
Up
Port S I/O, RXD of SCI1
PS3
TXD1
—
—
—
VDDX
PERS/PPSS
Up
Port S I/O, TXD of SCI1
-
PS4
MISO0
—
—
—
VDDX
PERS/PPSS
Up
Port S I/O, MISO of SPI0
-
-
PS5
MOSI0
—
—
—
VDDX
PERS/PPSS
Up
Port S I/O, MOSI of SPI0
95
-
-
PS6
SCK0
—
—
—
VDDX
PERS/PPSS
Up
Port S I/O, SCK of SPI0
96
-
-
PS7
SS0
—
—
—
VDDX
PERS/PPSS
Up
Port S I/O, SS of SPI0
97
67
54
TEST
—
—
—
—
N.A.
RESET pin
DOWN
98
68
-
PJ7
KWJ7
—
—
—
VDDX
PERJ/PPSJ
Up
Port J I/O, interrupt
99
69
-
PJ6
KWJ6
—
—
—
VDDX
PERJ/PPSJ
Up
Port J I/O, interrupt
100
70
55
PM5
SCK0
—
—
—
VDDX
PERM/PPSM
Disabled
Port M I/O, SCK of SPI0
101
71
56
PM4
MOSI0
—
—
—
VDDX
PERM/PPSM
Disabled
Port M I/O, MOSI of
SPI0
102
72
57
PM3
SS0
—
—
—
VDDX
PERM/PPSM
Disabled
Port M I/O, SS of SPI0
103
73
58
PM2
MISO0
—
—
—
VDDX
PERM/PPSM
Disabled
Port M I/O, MISO of
SPI0
104
74
59
PM1
TXCAN0
TXD1
—
—
VDDX
PERM/PPSM
Disabled
Port M I/O, TX of CAN0,
TXD of SCI1
105
75
60
PM0
RXCAN0
RXD1
—
—
VDDX
PERM/PPSM
Disabled
Port M I/O, RX of CAN0,
RXD of SCI1
Test input
Device Overview S12XS Family
39
Package Terminal
LQFP
112
QFP
80
LQFP
64
106
76
107
Function
S12XS Family Reference Manual, Rev. 1.10
Pin
2nd
Func.
3rd
Func.
4th
Func.
5th
Func.
61
VSSX1
—
—
—
—
77
62
VDDX1
—
—
—
108
-
-
PK7
—
—
109
78
63
PP7
KWP7
110
-
-
PP6
111
79
64
112
80
-
Power
Supply
Description
CTRL
Reset
State
—
—
—
—
—
—
—
—
—
—
—
VDDX
PUCR
Up
PWM7
—
—
VDDX
PERP/PPSP
Disabled
Port P I/O, interrupt,
PWM channel
KWP6
PWM6
—
—
VDDX
PERP/PPSP
Disabled
Port P I/O, interrupt,
PWM channel
PP5
KWP5
PWM5
—
—
VDDX
PERP/PPSP
Disabled
Port P I/O, interrupt,
PWM channel
PP4
KWP4
PWM4
—
—
VDDX
PERP/PPSP
Disabled
Port P I/O, interrupt,
PWM channel
Table shows a superset of pin functions. Not all functions are available on all derivatives
2 For compatibility to XE family
3 VRL and VSSA share single pin on 64 package option
1
Internal Pull
Resistor
Port K I/O
Device Overview S12XS Family
40
Table 1-6. Pin-Out Summary1 (continued)
Freescale Semiconductor
Device Overview S12XS Family
1.2.3
Detailed Signal Descriptions
NOTE
The pin list of the largest package version of each S12XS Family derivative
gives the complete of interface signals that also exist on smaller package
options, although some of them are not bonded out. For devices assembled
in smaller packages all non-bonded out pins should be configured as outputs
after reset in order to avoid current drawn from floating inputs. Refer to
Table 1-6 for affected pins.
1.2.3.1
EXTAL, XTAL — Oscillator Pins
EXTAL and XTAL are the crystal driver and external clock pins. On reset all the device clocks are derived
from the EXTAL input frequency. XTAL is the oscillator output.
1.2.3.2
RESET — External Reset Pin
The RESET pin is an active low bidirectional control signal. It acts as an input to initialize the MCU to a
known start-up state. As an output it is driven low to indicate when any internal MCU reset source triggers.
The RESET pin has an internal pull-up device.
1.2.3.3
TEST — Test Pin
This input only pin is reserved for factory test. This pin has a pull-down device.
NOTE
The TEST pin must be tied to VSS in all applications.
1.2.3.4
BKGD / MODC — Background Debug and Mode Pin
The BKGD/MODC pin is used as a pseudo-open-drain pin for the background debug communication. It
is used as a MCU operating mode select pin during reset. The state of this pin is latched to the MODC bit
at the rising edge of RESET. The BKGD pin has an internal pull-up device.
1.2.3.5
PAD[15:0] / AN[15:0] — Port AD Input Pins of ATD0
PAD[15:0] are general-purpose input or output pins and analog inputs AN[15:0] of the analog-to-digital
converter ATD0.
1.2.3.6
PA[7:0] — Port A I/O Pins
PA[7:0] are general-purpose input or output pins.
1.2.3.7
PB[7:0] — Port B I/O Pins
PB[7:0] are general-purpose input or output pins.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
41
Device Overview S12XS Family
1.2.3.8
PE7 / ECLKX2 / XCLKS — Port E I/O Pin 7
PE7 is a general-purpose input or output pin. ECLKX2 is a clock output of twice the internal bus
frequency. The XCLKS is an input signal which controls whether a crystal in combination with the internal
loop controlled Pierce oscillator is used or whether full swing Pierce oscillator/external clock circuitry is
used (refer to Section 1.10 Oscillator Configuration). An internal pull-up is enabled during reset.
1.2.3.9
PE[6:5] — Port E I/O Pin 6-5
PE[6:5] are a general-purpose input or output pins.
1.2.3.10
PE4 / ECLK — Port E I/O Pin 4
PE4 is a general-purpose input or output pin. It can be configured to output the internal bus clock ECLK.
ECLK can be used as a timing reference. The ECLK output has a programmable prescaler.
1.2.3.11
PE[3:2] — Port E I/O Pin 3
PE[3:2] are a general-purpose input or output pins.
1.2.3.12
PE1 / IRQ — Port E Input Pin 1
PE1 is a general-purpose input pin and the maskable interrupt request input that provides a means of
applying asynchronous interrupt requests. This will wake up the MCU from stop or wait mode.
1.2.3.13
PE0 / XIRQ — Port E Input Pin 0
PE0 is a general-purpose input pin and the non-maskable interrupt request input that provides a means of
applying asynchronous interrupt requests. This will wake up the MCU from stop or wait mode. The XIRQ
interrupt is level sensitive and active low. As XIRQ is level sensitive, while this pin is low the MCU will
not enter STOP mode.
1.2.3.14
PH[7:0] / KWH[7:0] — Port H I/O Pins
PH[7:0] are a general-purpose input or output pins. They can be configured as keypad wakeup inputs.
1.2.3.15
PJ[7:6] / KWJ[7:6] — PORT J I/O Pins 7-6
PJ[7:6] are a general-purpose input or output pins. They can be configured as keypad wakeup inputs.
1.2.3.16
PJ[1:0] / KWJ[1:0] — PORT J I/O Pins 1-0
PJ[1:0] are a general-purpose input or output pins. They can be configured as keypad wakeup inputs.
1.2.3.17
PK[7,5:0] — Port K I/O Pins 7 and 5-0
PK[7,5:0] are a general-purpose input or output pins.
S12XS Family Reference Manual, Rev. 1.10
42
Freescale Semiconductor
Device Overview S12XS Family
1.2.3.18
PM[7:6] — Port M I/O Pins 7-6
PM[7:6] are a general-purpose input or output pins.
1.2.3.19
PM5 / SCK0 — Port M I/O Pin 5
PM5 is a general-purpose input or output pin. It can be configured as the serial clock pin SCK of the serial
peripheral interface 0 (SPI0).
1.2.3.20
PM4 / MOSI0 — Port M I/O Pin 4
PM4 is a general-purpose input or output pin. It can be configured as the master output (during master
mode) or slave input pin (during slave mode) MOSI for the serial peripheral interface 0 (SPI0).
1.2.3.21
PM3 / SS0 — Port M I/O Pin 3
PM3 is a general-purpose input or output pin. It can be configured as the slave select pin SS of the serial
peripheral interface 0 (SPI0).
1.2.3.22
PM2 / MISO0 — Port M I/O Pin 2
PM2 is a general-purpose input or output pin. It can be configured as the master input (during master
mode) or slave output pin (during slave mode) MISO for the serial peripheral interface 0 (SPI0).
1.2.3.23
PM1 / TXCAN0 / TXD1 — Port M I/O Pin 1
PM1 is a general-purpose input or output pin. It can be configured as the transmit pin TXCAN of the
scalable controller area network controller 0 (CAN0). It can be configured as the transmit pin TXD of
serial communication interface 1 (SCI1).
1.2.3.24
PM0 / RXCAN0 / RXD1 — Port M I/O Pin 0
PM0 is a general-purpose input or output pin. It can be configured as the receive pin RXCAN of the
scalable controller area network controller 0 (CAN0). It can be configured as the receive pin RXD of serial
communication interface 1 (SCI1).
1.2.3.25
PP7 / KWP7 / PWM7 — Port P I/O Pin 7
PP7 is a general-purpose input or output pin. It can be configured as keypad wakeup input. It can be
configured as pulse width modulator (PWM) channel 7 output or emergency shutdown input.
1.2.3.26
PP[6:3] / KWP[6:3] / PWM[6:3] — Port P I/O Pins 6-3
PP[6:3] are a general-purpose input or output pins. They can be configured as keypad wakeup inputs. They
can be configured as pulse width modulator (PWM) channel 6-3 output.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
43
Device Overview S12XS Family
1.2.3.27
PP2 / KWP2 / PWM2 / TXD1 / IOC2 — Port P I/O Pin 2
PP2 is a general-purpose input or output pin. It can be configured as a keypad wakeup input. It can be
configured as pulse width modulator (PWM) channel 2 output, TIM channel 2 or as the transmit pin TXD
of serial communication interface 1 (SCI1).
1.2.3.28
PP1 / KWP1 / PWM1 / IOC1 — Port P I/O Pin 1
PP1 is a general-purpose input or output pin. It can be configured as a keypad wakeup input. It can be
configured as pulse width modulator (PWM) channel 1 output, TIM channel 1.
1.2.3.29
PP0 / KWP0 / PWM0 / RXD1 / IOC0 — Port P I/O Pin 0
PP0 is a general-purpose input or output pin. It can be configured as a keypad wakeup input. It can be
configured as pulse width modulator (PWM) channel 0 output, TIM channel 0 or as the receive pin RXD
of serial communication interface 1 (SCI1).
1.2.3.30
PS7 / SS0 — Port S I/O Pin 7
PS7 is a general-purpose input or output pin. It can be configured as the slave select pin SS of the serial
peripheral interface 0 (SPI0).
1.2.3.31
PS6 / SCK0 — Port S I/O Pin 6
PS6 is a general-purpose input or output pin. It can be configured as the serial clock pin SCK of the serial
peripheral interface 0 (SPI0).
1.2.3.32
PS5 / MOSI0 — Port S I/O Pin 5
PS5 is a general-purpose input or output pin. It can be configured as master output (during master mode)
or slave input pin (during slave mode) MOSI of the serial peripheral interface 0 (SPI0).
1.2.3.33
PS4 / MISO0 — Port S I/O Pin 4
PS4 is a general-purpose input or output pin. It can be configured as master input (during master mode) or
slave output pin (during slave mode) MOSI of the serial peripheral interface 0 (SPI0).
1.2.3.34
PS3 / TXD1 — Port S I/O Pin 3
PS3 is a general-purpose input or output pin. It can be configured as the transmit pin TXD of serial
communication interface 1 (SCI1).
1.2.3.35
PS2 / RXD1 — Port S I/O Pin 2
PS2 is a general-purpose input or output pin. It can be configured as the receive pin RXD of serial
communication interface 1 (SCI1).
S12XS Family Reference Manual, Rev. 1.10
44
Freescale Semiconductor
Device Overview S12XS Family
1.2.3.36
PS1 / TXD0 — Port S I/O Pin 1
PS1 is a general-purpose input or output pin. It can be configured as the transmit pin TXD of serial
communication interface 0 (SCI0).
1.2.3.37
PS0 / RXD0 — Port S I/O Pin 0
PS0 is a general-purpose input or output pin. It can be configured as the receive pin RXD of serial
communication interface 0 (SCI0).
1.2.3.38
PT[7:6] / IOC[7:6] / PWM[7:6] — Port T I/O Pins 7-6
PT[7:6] are general-purpose input or output pins. They can be configured as timer (TIM) channel 7-6 or
pulse width modulator (PWM) outputs 7-6
1.2.3.39
PT5 / IOC5 / VREG_API — Port T I/O Pin 5
PT[5] is a general-purpose input or output pin. It can be configured as timer (TIM) channel 5, pulse width
modulator (PWM) output 5 or as the VREG_API signal output.
1.2.3.40
PT4 / IOC4 / PWM4 — Port T I/O Pin 4
PT4 is a general-purpose input or output pin. It can be configured as timer (TIM) channel 4 or pulse width
modulator (PWM) output 4.
1.2.3.41
PT[3:0] / IOC[3:0] — Port T I/O Pin [3:0]
PT[3:0] are a general-purpose input or output pins. They can be configured as timer (TIM) channels 3-0.
1.2.4
Power Supply Pins
S12XS Family power and ground pins are described below.
Because fast signal transitions place high, short-duration current demands on the power supply, use bypass
capacitors with high-frequency characteristics and place them as close to the MCU as possible.
NOTE
All VSS pins must be connected together in the application.
1.2.4.1
VDDX[2:1], VSSX[2:1] — Power and Ground Pins for I/O Drivers
External power and ground for I/O drivers. Bypass requirements depend on how heavily the MCU pins are
loaded. All VDDX pins are connected together internally. All VSSX pins are connected together internally.
1.2.4.2
VDDR — Power Pin for Internal Voltage Regulator
Power supply input to the internal voltage regulator.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
45
Device Overview S12XS Family
1.2.4.3
VDD, VSS2, VSS3 — Core Power Pins
The voltage supply of nominally 1.8 V is derived from the internal voltage regulator. The return current
path is through the VSS2 and VSS3 pins. No static external loading of these pins is permitted.
1.2.4.4
VDDF, VSS1 — NVM Power Pins
The voltage supply of nominally 2.8 V is derived from the internal voltage regulator. The return current
path is through the VSS1 pin. No static external loading of these pins is permitted.
1.2.4.5
VDDA, VSSA — Power Supply Pins for ATD and Voltage Regulator
These are the power supply and ground input pins for the analog-to-digital converters and the voltage
regulator.
1.2.4.6
VRH, VRL — ATD Reference Voltage Input Pins
VRH and VRL are the reference voltage input pins for the analog-to-digital converter.
1.2.4.7
VDDPLL, VSSPLL — Power Supply Pins for PLL
These pins provide operating voltage and ground for the oscillator and the phased-locked loop. The voltage
supply of nominally 1.8 V is derived from the internal voltage regulator. This allows the supply voltage to
the oscillator and PLL to be bypassed independently. This voltage is generated by the internal voltage
regulator. No static external loading of these pins is permitted.
Table 1-7. Power and Ground Connection Summary
Mnemonic
Nominal
Voltage
VDDR
5.0 V
External power supply to internal voltage
regulator
VDDX[2:1]
5.0 V
VSSX[2:1]
0V
External power and ground, supply to pin
drivers
VDDA
5.0 V
VSSA
0V
VRL
0V
VRH
5.0 V
VDD
1.8 V
VSS1, VSS2,
VSS3
0V
VDDF
2.8 V
Description
Operating voltage and ground for the
analog-to-digital converters and the
reference for the internal voltage regulator,
allows the supply voltage to the A/D to be
bypassed independently.
Reference voltages for the analog-to-digital
converter.
Internal power and ground generated by
internal regulator for the internal core.
Internal power and ground generated by
internal regulator for the internal NVM.
S12XS Family Reference Manual, Rev. 1.10
46
Freescale Semiconductor
Device Overview S12XS Family
Table 1-7. Power and Ground Connection Summary
Mnemonic
Nominal
Voltage
VDDPLL
1.8 V
VSSPLL
0V
Description
Provides operating voltage and ground for
the phased-locked loop. This allows the
supply voltage to the PLL to be bypassed
independently. Internal power and ground
generated by internal regulator.
S12XS Family Reference Manual, Rev. 1.10
47
Freescale Semiconductor
Device Overview S12XS Family
1.3
System Clock Description
The clock and reset generator module (CRG) provides the internal clock signals for the core and all
peripheral modules. Figure 1-6 shows the clock connections from the CRG to all modules.
Consult the S12XECRG section for details on clock generation.
NOTE
The XS family uses the XE family clock and reset generator module.
Therefore all CRG references are related to S12XECRG.
SCI0 . . SCI 1
SPI0
CAN0
ATD0
Bus Clock
PIT
EXTAL
Oscillator Clock
TIM
CRG
PIM
XTAL
Core Clock
PWM
RAM
S12X
FLASH
Figure 1-6. Clock Connections
The system clock can be supplied in several ways enabling a range of system operating frequencies to be
supported:
• The on-chip phase locked loop (PLL)
• the PLL self clocking
• the oscillator
S12XS Family Reference Manual, Rev. 1.10
48
Freescale Semiconductor
Device Overview S12XS Family
The clock generated by the PLL or oscillator provides the main system clock frequencies core clock and
bus clock. As shown in Figure 1-6, these system clocks are used throughout the MCU to drive the core,
the memories, and the peripherals.
The program Flash memory is supplied by the bus clock and the oscillator clock. The oscillator clock is
used as a time base to derive the program and erase times for the NVMs.
The CAN modules may be configured to have their clock sources derived either from the bus clock or
directly from the oscillator clock. This allows the user to select its clock based on the required jitter
performance.
In order to ensure the presence of the clock the MCU includes an on-chip clock monitor connected to the
output of the oscillator. The clock monitor can be configured to invoke the PLL self-clocking mode or to
generate a system reset if it is allowed to time out as a result of no oscillator clock being present.
In addition to the clock monitor, the MCU also provides a clock quality checker which performs a more
accurate check of the clock. The clock quality checker counts a predetermined number of clock edges
within a defined time window to insure that the clock is running. The checker can be invoked following
specific events such as on wake-up or clock monitor failure.
1.4
Modes of Operation
The MCU can operate in different modes. These are described in 1.4.1 Chip Configuration Summary.
The MCU can operate in different power modes to facilitate power saving when full system performance
is not required. These are described in 1.4.2 Power Modes.
Some modules feature a software programmable option to freeze the module status whilst the background
debug module is active to facilitate debugging. This is described in 1.4.3 Freeze Mode.
1.4.1
Chip Configuration Summary
The different modes and the security state of the MCU affect the debug features (enabled or disabled).
The operating mode out of reset is determined by the state of the MODC signal during reset (see Table 18). The MODC bit in the MODE register shows the current operating mode and provides limited mode
switching during operation. The state of the MODC signal is latched into this bit on the rising edge of
RESET.
Table 1-8. Chip Modes
Chip Modes
1.4.1.1
MODC
Normal single chip
1
Special single chip
0
Normal Single-Chip Mode
This mode is intended for normal device operation. The opcode from the on-chip memory is being
executed after reset (requires the reset vector to be programmed correctly). The processor program is
executed from internal memory.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
49
Device Overview S12XS Family
1.4.1.2
Special Single-Chip Mode
This mode is used for debugging single-chip operation, boot-strapping, or security related operations. The
background debug module BDM is active in this mode. The CPU executes a monitor program located in
an on-chip ROM. BDM firmware waits for additional serial commands through the BKGD pin.
1.4.2
Power Modes
The MCU features two main low-power modes. Consult the respective section for module specific
behavior in system stop, system pseudo stop, and system wait mode. An important source of information
about the clock system is the Clock and Reset Generator section (CRG).
1.4.2.1
System Stop Modes
The system stop modes are entered if the CPU executes the STOP instruction unless an NVM command
is active. Depending on the state of the PSTP bit in the CLKSEL register the MCU goes into pseudo stop
mode or full stop mode. Please refer to CRG section. Asserting RESET, XIRQ, IRQ or any other interrupt
that is not masked exits system stop modes. System stop modes can be exited by CPU activity, depending
on the configuration of the interrupt request.
If the CPU executes the STOP instruction whilst an NVM command is being processed, then the system
clocks continue running until NVM activity is completed. If a non-masked interrupt occurs within this time
then the system does not effectively enter stop mode although the STOP instruction has been executed.
1.4.2.2
Full Stop Mode
The oscillator is stopped in this mode. By default all clocks are switched off and all counters and dividers
remain frozen. The Autonomous Periodic Interrupt (API) and ATD module may be enabled to self wake
the device. A Fast wake up mode is available to allow the device to wake from Full Stop mode immediately
on the PLL internal clock without starting the oscillator clock.
1.4.2.3
Pseudo Stop Mode
In this mode the system clocks are stopped but the oscillator is still running and the real time interrupt
(RTI) and watchdog (COP), API and ATD modules may be enabled. Other peripherals are turned off. This
mode consumes more current than system stop mode but, as the oscillator continues to run, the full speed
wake up time from this mode is significantly shorter.
1.4.2.4
Wait Mode
This mode is entered when the CPU executes the WAI instruction. In this mode the CPU will not execute
instructions. The internal CPU clock is switched off. All peripherals can be active in system wait mode.
For further power consumption the peripherals can individually turn off their local clocks. Asserting
RESET, XIRQ, IRQ or any other interrupt that is not masked ends system wait mode.
S12XS Family Reference Manual, Rev. 1.10
50
Freescale Semiconductor
Device Overview S12XS Family
1.4.2.5
Run Mode
Although this is not a low-power mode, unused peripheral modules should not be enabled in order to save
power.
1.4.3
Freeze Mode
The timer module, pulse width modulator, analog-to-digital converters, and the periodic interrupt timer
provide a software programmable option to freeze the module status when the background debug module
is active. This is useful when debugging application software. For detailed description of the behavior of
the ATD, TIM, PWM, and PIT when the background debug module is active consult the corresponding
section.
1.5
Security
The MCU security mechanism prevents unauthorized access to the Flash memory. For a detailed
description of the security features refer to the S12XS9SEC section.
1.6
Resets and Interrupts
Consult the CPU12/CPU12X Reference Manual and the S12XINT section for information on exception
processing.
NOTE
When referring to the S12XINT section please be aware that the XS family
neither features an XGATE nor an MPU module.
1.6.1
Resets
Resets are explained in detail in the Clock Reset Generator (S12XECRG) section.
Table 1-9. Reset Sources and Vector Locations
1.6.2
Vector Address
Reset Source
CCR
Mask
Local Enable
$FFFE
Power-On Reset (POR)
None
None
$FFFE
Low Voltage Reset (LVR)
None
None
$FFFE
External pin RESET
None
None
$FFFE
Illegal Address Reset
None
None
$FFFC
Clock monitor reset
None
PLLCTL (CME, SCME)
$FFFA
COP watchdog reset
None
COP rate select
Vectors
Table 1-10 lists all interrupt sources and vectors in the default order of priority. The interrupt module
(S12XINT) provides an interrupt vector base register (IVBR) to relocate the vectors. Associated with each
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
51
Device Overview S12XS Family
I-bit maskable service request is a configuration register. It selects if the service request is enabled and the
service request priority level.
Table 1-10. Interrupt Vector Locations (Sheet 1 of 2)
Vector Address1
Interrupt Source
CCR
Mask
Local Enable
STOP
WAIT
Wake up Wake up
Vector base + $F8
Unimplemented instruction trap
None
None
—
—
Vector base+ $F6
SWI
None
None
—
—
Vector base+ $F4
XIRQ
X Bit
None
Yes
Yes
Vector base+ $F2
IRQ
I bit
IRQCR (IRQEN)
Yes
Yes
Vector base+ $F0
Real time interrupt
I bit
CRGINT (RTIE)
Vector base+ $EE
TIM timer channel 0
I bit
TIE (C0I)
No
Yes
Vector base + $EC
TIM timer channel 1
I bit
TIE (C1I)
No
Yes
Vector base+ $EA
TIM timer channel 2
I bit
TIE (C2I)
No
Yes
Vector base+ $E8
TIM timer channel 3
I bit
TIE (C3I)
No
Yes
Vector base+ $E6
TIM timer channel 4
I bit
TIE (C4I)
No
Yes
Vector base+ $E4
TIM timer channel 5
I bit
TIE (C5I)
No
Yes
Vector base + $E2
TIM timer channel 6
I bit
TIE (C6I)
No
Yes
Vector base+ $E0
TIM timer channel 7
I bit
TIE (C7I)
No
Yes
Vector base+ $DE
TIM timer overflow
I bit
TSRC2 (TOF)
No
Yes
Vector base+ $DC
TIM Pulse accumulator A overflow
I bit
PACTL (PAOVI)
No
Yes
Vector base + $DA
TIM Pulse accumulator input edge
I bit
PACTL (PAI)
No
Yes
Vector base + $D8
SPI0
I bit
SPI0CR1 (SPIE, SPTIE)
No
Yes
Vector base+ $D6
SCI0
I bit
SCI0CR2
(TIE, TCIE, RIE, ILIE)
Yes
Yes
Vector base + $D4
SCI1
I bit
SCI1CR2
(TIE, TCIE, RIE, ILIE)
Yes
Yes
Vector base + $D2
ATD0
I bit
ATD0CTL2 (ASCIE)
Yes
Yes
Refer to CRG
interrupt section
Reserved
Vector base + $D0
Vector base + $CE
Port J
I bit
PIEJ (PIEJ7-PIEJ0)
Yes
Yes
Vector base + $CC
Port H
I bit
PIEH (PIEH7-PIEH0)
Yes
Yes
Vector base + $CA
Reserved
Vector base + $C8
Reserved
Vector base + $C6
CRG PLL lock
I bit
CRGINT(LOCKIE)
Refer to CRG
interrupt section
Vector base + $C4
CRG self-clock mode
I bit
CRGINT (SCMIE)
Refer to CRG
interrupt section
Vector base + $C2
to
Vector base + $BC
Reserved
S12XS Family Reference Manual, Rev. 1.10
52
Freescale Semiconductor
Device Overview S12XS Family
Table 1-10. Interrupt Vector Locations (Sheet 2 of 2)
Vector Address1
Interrupt Source
CCR
Mask
Local Enable
Vector base + $BA
FLASH Fault Detect
I bit
FCNFG2 (SFDIE, DFDIE)
No
No
Vector base + $B8
FLASH
I bit
FCNFG (CCIE)
No
Yes
Vector base + $B6
CAN0 wake-up
I bit
CAN0RIER (WUPIE)
Yes
Yes
Vector base + $B4
CAN0 errors
I bit
CAN0RIER (CSCIE,
OVRIE)
No
Yes
Vector base + $B2
CAN0 receive
I bit
CAN0RIER (RXFIE)
No
Yes
Vector base + $B0
CAN0 transmit
I bit
CAN0TIER (TXEIE[2:0])
No
Yes
Vector base + $AE
to
Vector base + $90
Reserved
Vector base + $8E
Port P Interrupt
I bit
PIEP (PIEP7-PIEP0)
Yes
Yes
Vector base+ $8C
PWM emergency shutdown
I bit
PWMSDN (PWMIE)
No
Yes
Vector base + $8A
to
Vector base + $82
Reserved
Vector base + $80
Low-voltage interrupt (LVI)
I bit
VREGCTRL (LVIE)
No
Yes
Vector base + $7E
Autonomous periodical interrupt (API)
I bit
VREGAPICTRL (APIE)
Yes
Yes
Vector base + $7C
High Temperature Interrupt (HTI)
I bit
VREGHTCL (HTIE)
No
Yes
Vector base + $7A
Periodic interrupt timer channel 0
I bit
PITINTE (PINTE0)
No
Yes
Vector base + $78
Periodic interrupt timer channel 1
I bit
PITINTE (PINTE1)
No
Yes
Vector base + $76
Periodic interrupt timer channel 2
I bit
PITINTE (PINTE2)
No
Yes
Vector base + $74
Periodic interrupt timer channel 3
I bit
PITINTE (PINTE3)
No
Yes
ATD0CTL2 (ACMPIE)
Yes
Yes
Vector base + $72
to
Vector base + $40
Vector base + $3E
Reserved
ATD0 Compare Interrupt
Vector base + $3C
to
Vector base + $14
Vector base + $12
1
STOP
WAIT
Wake up Wake up
Vector base + $10
16 bits vector address based
1.6.3
I bit
Reserved
System Call Interrupt (SYS)
—
None
—
—
Spurious interrupt
—
None
—
—
Effects of Reset
When a reset occurs, MCU registers and control bits are initialized. Refer to the respective block sections
for register reset states.
On each reset, the Flash module executes a reset sequence to load Flash configuration registers.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
53
Device Overview S12XS Family
1.6.3.1
Flash Configuration Reset Sequence Phase
On each reset, the Flash module will hold CPU activity while loading Flash module registers from the
Flash memory. If double faults are detected in the reset phase, Flash module protection and security may
be active on leaving reset. This is explained in more detail in the Flash module section.
1.6.3.2
Reset While Flash Command Active
If a reset occurs while any Flash command is in progress, that command will be immediately aborted. The
state of the word being programmed or the sector/block being erased is not guaranteed.
1.6.3.3
I/O Pins
Refer to the PIM section for reset configurations of all peripheral module ports.
1.6.3.4
Memory
The RAM arrays are not initialized out of reset.
1.6.3.5
COP Configuration
The COP time-out rate bits CR[2:0] and the WCOP bit in the COPCTL register are loaded from the Flash
register FOPT. See Table 1-11 and Table 1-12 for coding. The FOPT register is loaded from the Flash
configuration field byte at global address $7FFF0E during the reset sequence.
If the MCU is secured the COP time-out rate is always set to the longest period (CR[2:0] = 111) after any
reset into Special Single Chip mode.
Table 1-11. Initial COP Rate Configuration
NV[2:0] in
FOPT Register
CR[2:0] in
COPCTL Register
000
111
001
110
010
101
011
100
100
011
101
010
110
001
111
000
Table 1-12. Initial WCOP Configuration
NV[3] in
FOPT Register
WCOP in
COPCTL Register
1
0
0
1
S12XS Family Reference Manual, Rev. 1.10
54
Freescale Semiconductor
Device Overview S12XS Family
1.7
1.7.1
ATD0 Configuration
External Trigger Input Connection
The ATD module includes four external trigger inputs ETRIG0, ETRIG1, ETRIG2, and ETRIG3. The
external trigger allows the user to synchronize ATD conversion to external trigger events. Table 1-13
shows the connection of the external trigger inputs.
Table 1-13. ATD0 External Trigger Sources
External Trigger
Input
Connectivity
ETRIG0
Pulse width modulator channel 1
ETRIG1
Pulse width modulator channel 3
ETRIG2
Periodic interrupt timer hardware trigger 0
ETRIG3
Periodic interrupt timer hardware trigger 1
Consult the ATD section for information about the analog-to-digital converter module. References to
freeze mode are equivalent to active BDM mode.
1.7.2
ATD0 Channel[17] Connection
Further to the 16 externally available channels, ATD0 features an extra channel[17] that is connected to
the internal temperature sensor at device level. To access this channel ATD0 must use the channel encoding
SC:CD:CC:CB:CA = 1:0:0:0:1 in ATDCTL5. For more temperature sensor information, please refer to
1.8.1 Temperature Sensor Configuration.
1.8
VREG Configuration
The device must be configured with the internal voltage regulator enabled. Operation in conjunction with
an external voltage regulator is not supported.
The API trimming register APITR is loaded from the Flash IFR option field at global address 0x40_00F0
bits[5:0] during the reset sequence. Currently factory programming of this IFR range is not supported.
Read access to reserved VREG register space returns “0”. Write accesses have no effect. This device does
not support access abort of reserved VREG register space.
1.8.1
Temperature Sensor Configuration
The VREG high temperature trimming register bits VREGHTTR[3:0] are loaded from the internal Flash
during the reset sequence. To use the high temperature interrupt within the specified limits (THTIA and
THTID) these bits must be loaded with 0x8. Currently factory programming is not supported.
The device temperature can be monitored on ATD0 channel[17]. The internal bandgap reference voltage
can also be mapped to ATD0 analog input channel[17]. The voltage regulator VSEL bit when set, maps
the bandgap and, when clear, maps the temperature sensor to ATD0 channel[17].
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
55
Device Overview S12XS Family
1.9
BDM Clock Configuration
The BDM alternate clock source is the oscillator clock.
1.10
Oscillator Configuration
The XCLKS is an input signal which controls whether a crystal in combination with the internal loop
controlled (low power) Pierce oscillator is used or whether full swing Pierce oscillator/external clock
circuitry is used.
The XCLKS signal selects the oscillator configuration during reset low phase while a clock quality check
is ongoing. This is the case for:
• Power on reset or low-voltage reset
• Clock monitor reset
• Any reset while in self-clock mode or full stop mode
S12XS Family Reference Manual, Rev. 1.10
56
Freescale Semiconductor
Device Overview S12XS Family
The selected oscillator configuration is frozen with the rising edge of the RESET pin in any of these above
described reset cases.
EXTAL
C1
MCU
Crystal or
Ceramic Resonator
XTAL
C2
VSSPLL
Figure 1-7. Loop Controlled Pierce Oscillator Connections (XCLKS = 1)
EXTAL
C1
MCU
RB
RS
Crystal or
Ceramic Resonator
XTAL
C2
RB=1MΩ ; RS specified by crystal vendor
VSSPLL
Figure 1-8. Full Swing Pierce Oscillator Connections (XCLKS = 0)
EXTAL
CMOS-Compatible
External Oscillator
MCU
XTAL
Not Connected
Figure 1-9. External Clock Connections (XCLKS = 0)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
57
Device Overview S12XS Family
S12XS Family Reference Manual, Rev. 1.10
58
Freescale Semiconductor
Chapter 2
Port Integration Module (S12XSPIMV1)
Revision History
Revision
Number
Revision Date
V01.04
02 Apr 2008
• Corrected reduced drive strength to 1/5
• Separated PE1,0 bit descriptions from other PE GPIO
V01.05
31 Mar 2009
• Corrected PERJ bit description
• Orthographical corrections
V01.06
18 Dec 2009
2.1
2.1.1
Sections
Affected
Table 2-1./2-61
Description of Changes
• Corrected PP0, PM0 pin descriptions
• Added function independency to wired-or bit descriptions
• Minor corrections
Introduction
Overview
The S12XS family Port Integration Module establishes the interface between the peripheral modules and
the I/O pins for all ports. It controls the electrical pin properties as well as the signal prioritization and
multiplexing on shared pins.
This document covers:
• Port A, B and K used as general purpose I/O
• Port E associated with the IRQ, XIRQ interrupt inputs
• Port T associated with 1 timer module
• Port S associated with 2 SCI module and 1 SPI module
• Port M associated with 1 MSCAN
• Port P connected to the PWM - inputs can be used as an external interrupt source
• Port H and J used as general purpose I/O - inputs can be used as an external interrupt source
• Port AD associated with one 16-channel ATD module
Most I/O pins can be configured by register bits to select data direction and drive strength, to enable and
select pull-up or pull-down devices.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
59
Port Integration Module (S12XSPIMV1)
NOTE
This document assumes the availability of all features (112-pin package
option). Some functions are not available on lower pin count package
options. Refer to the pin-out summary section.
2.1.2
Features
The Port Integration Module includes these distinctive registers:
• Data and data direction registers for Ports A, B, E, K, T, S, M, P, H, J, and AD when used as
general-purpose I/O
• Control registers to enable/disable pull-device and select pull-ups/pull-downs on Ports T, S, M, P,
H, and J on per-pin basis
• Control registers to enable/disable pull-up devices on Port AD on per-pin basis
• Single control register to enable/disable pull-ups on Ports A, B, E, and K on per-port basis and on
BKGD pin
• Control registers to enable/disable reduced output drive on Ports T, S, M, P, H, J, and AD on per-pin
basis
• Single control register to enable/disable reduced output drive on Ports A, B, E, and K on per-port
basis
• Control registers to enable/disable open-drain (wired-or) mode on Ports S, and M
• Interrupt flag register for pin interrupts on Ports P, H, and J
• Control register to configure IRQ pin operation
• Routing registers to support module port relocation
• Free-running clock outputs
A standard port pin has the following minimum features:
• Input/output selection
• 5V output drive with two selectable drive strengths
• 5V digital and analog input
• Input with selectable pull-up or pull-down device
Optional features supported on dedicated pins:
•
Open drain for wired-or connections
•
Interrupt inputs with glitch filtering
2.2
External Signal Description
This section lists and describes the signals that connect off-chip.
Table shows all the pins and their functions that are controlled by the Port Integration Module. Refer to
the device definition for the availability of the individual pins in the different package options.
S12XS Family Reference Manual, Rev. 1.10
60
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
NOTE
If there is more than one function associated with a pin, the priority is
indicated by the position in the table from top (highest priority) to bottom
(lowest priority)
Table 2-1. Pin Functions and Priorities
Port
Pin Name
Pin Function
& Priority1
I/O
-
BKGD
MODC 2
I
Description
MODC input during RESET
BKGD
I/O S12X_BDM communication pin
Pin Function
after Reset
BKGD
A
PA[7:0]
GPIO
I/O General purpose
GPIO
B
PB[7:0]
GPIO
I/O General purpose
GPIO
E
PE[7]
XCLKS 2
I
ECLKX2
O Free-running clock at core clock rate (ECLK x 2)
GPIO
I/O General purpose
PE[6:5]
GPIO
I/O General purpose
PE[4]
ECLK
O Free-running clock at bus clock rate or programmable
down-scaled bus clock
GPIO
I/O General purpose
PE[3:2]
GPIO
I/O General purpose
PE[1]
IRQ
I
Maskable level- or falling edge-sensitive interrupt
GPI
I
General-purpose
XIRQ
I
Non-maskable level-sensitive interrupt
GPI
I
General-purpose
PE[0]
K
External clock selection input during RESET
PK[7,5:0]
GPIO
I/O General purpose
GPIO
GPIO
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
61
Port Integration Module (S12XSPIMV1)
Table 2-1. Pin Functions and Priorities (continued)
Port
Pin Name
Pin Function
& Priority1
T
PT7
IOC7
(PWM7)
PT6
I/O Timer Channel 6
I/O General purpose
IOC5
I/O Timer Channel 5
PS7
PS6
PS5
IOC4
I/O Timer Channel 4
IOC[3:0]
SS0
PS3
PS2
PS1
PS0
O Pulse Width Modulator channel 4
I/O General purpose
I/O Timer Channel 3 - 0
I/O General purpose
I/O Serial Peripheral Interface 0 slave select output in master mode,
input in slave mode or master mode.
GPIO
I/O General purpose
SCK0
I/O Serial Peripheral Interface 0 serial clock pin
GPIO
I/O General purpose
MOSI0
GPIO
PS4
O VREG Autonomous Periodical Interrupt Clock
I/O General purpose
GPIO
S
O Pulse Width Modulator channel 5
GPIO
GPIO
PT[3:0]
O Pulse Width Modulator channel 6
GPIO
(PWM4)
MISO0
I/O General purpose
I/O Serial Peripheral Interface 0 master in/slave out pin
I/O General purpose
TXD1
O Serial Communication Interface 1 transmit pin
GPIO
I/O General purpose
I
Serial Communication Interface 1 receive pin
GPIO
I/O General purpose
TXD0
O Serial Communication Interface 0 transmit pin
GPIO
I/O General purpose
RXD0
GPIO
GPIO
I/O Serial Peripheral Interface 0 master out/slave in pin
GPIO
RXD1
GPIO
I/O Pulse Width Modulator channel 7; emergency shut-down
IOC6
VREG_API
PT4
I/O Timer Channel 7
I/O General purpose
(PWM5)
Pin Function
after Reset
Description
GPIO
(PWM6)
PT5
I/O
I
Serial Communication Interface 0 receive pin
I/O General purpose
S12XS Family Reference Manual, Rev. 1.10
62
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-1. Pin Functions and Priorities (continued)
Port
Pin Name
Pin Function
& Priority1
M
PM[7:6]
GPIO
PM5
(SCK0)
GPIO
PM4
PM3
PM2
(MOSI0)
I/O General purpose
I/O Serial Peripheral Interface 0 master out/slave in pin
I/O Serial Peripheral Interface 0 slave select output in master mode,
input in slave mode or master mode.
GPIO
I/O General purpose
TXCAN0
GPIO
I/O Serial Peripheral Interface 0 master in/slave out pin
I/O General purpose
O MSCAN0 transmit pin
O Serial Communication Interface 1 transmit pin
I/O General purpose
RXCAN0
I
MSCAN0 receive pin
(RXD1)
I
Serial Communication Interface 1 receive pin
GPIO
GPIO
I/O General purpose
(SS0)
(MISO0)
Pin Function
after Reset
I/O Serial Peripheral Interface 0 serial clock pin
I/O General purpose
(TXD1)
PM0
Description
GPIO
GPIO
PM1
I/O
I/O General purpose
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
63
Port Integration Module (S12XSPIMV1)
Table 2-1. Pin Functions and Priorities (continued)
Port
Pin Name
Pin Function
& Priority1
P
PP7
PWM7
GPIO/KWP7
PP[6:3]
PWM[6:3]
GPIO/KWP[6:3]
PP2
PP0
O Pulse Width Modulator channel 6 - 3
I/O General purpose; with interrupt
I/O Timer Channel 2
(TXD1)
O Serial Communication Interface 1 transmit pin
I/O General purpose; with interrupt
PWM1
O Pulse Width Modulator channel 1
(IOC1)
I/O Timer Channel 1
I/O General purpose; with interrupt
PWM0
O Pulse Width Modulator channel 0
(IOC0)
I/O Timer Channel 0
I
Serial Communication Interface 1 receive pin
GPIO/KWP0
I/O General purpose; with interrupt
H
PH[7:0]
GPIO/KWH[7:0]
I/O General purpose; with interrupt
GPIO
J
PJ[7:6]
GPIO/KWJ[7:6]
I/O General purpose; with interrupt
GPIO
PJ[1:0]
GPIO/KWJ[1:0]
I/O General purpose; with interrupt
PAD[15:0]
GPIO
AD
AN[15:0]
2
GPIO
I/O General purpose; with interrupt
(IOC2)
(RXD1)
1
I/O Pulse Width Modulator channel 7; emergency shut-down
O Pulse Width Modulator channel 2
GPIO/KWP1
Pin Function
after Reset
Description
PWM2
GPIO/KWP2
PP1
I/O
I/O General purpose
I
GPIO
ATD analog
Signals in brackets denote alternative module routing pins.
Function active when RESET asserted.
2.3
Memory Map and Register Definition
This section provides a detailed description of all Port Integration Module registers.
S12XS Family Reference Manual, Rev. 1.10
64
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.1
Memory Map
Table 2-2 shows the register map of the Port Integration Module.
Table 2-2. Block Memory Map
Port
A
B
E
A
B
E
K
E
K
Offset or
Address
Register
Access
Reset Value
Section/Page
0x0000
PORTA—Port A Data Register
R/W
0x00
2.3.3/2-75
0x0001
PORTB—Port B Data Register
R/W
0x00
2.3.4/2-75
0x0002
DDRA—Port A Data Direction Register
R/W
0x00
2.3.5/2-76
0x0003
DDRB—Port B Data Direction Register
R/W
0x00
2.3.6/2-76
0x0004
:
0x0007
PIM Reserved
R
0x00
2.3.7/2-77
0x0008
PORTE—Port E Data Register
R/W1
0x00
2.3.8/2-77
0x0009
DDRE—Port E Data Direction Register
R/W1
0x00
2.3.9/2-78
0x000A
:
0x000B
Non-PIM address range2
-
-
-
0x000C
PUCR—Pull-up Control Register
R/W1
0xD0
2.3.10/2-79
0x000D
RDRIV—Reduced Drive Register
R/W1
0x00
2.3.11/2-80
0x000E
:
0x001B
Non-PIM address range2
-
-
-
0x001C
ECLKCTL—ECLK Control Register
R/W1
0b3100_0000
2.3.12/2-81
0x001D
PIM Reserved
R
0x00
2.3.13/2-82
0x001E
IRQCR—IRQ Control Register
R/W1
0x40
2.3.14/2-83
0x001F
PIM Reserved
R
0x00
2.3.15/2-83
0x0020
:
0x0031
Non-PIM address range2
-
-
-
0x0032
PORTK—Port K Data Register
R/W
0x00
2.3.16/2-84
0x0033
DDRK—Port K Data Direction Register
R/W
0x00
2.3.17/2-84
0x0034
:
0x023F
Non-PIM address range2
-
-
-
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
65
Port Integration Module (S12XSPIMV1)
Table 2-2. Block Memory Map (continued)
Port
Offset or
Address
T
0x0240
S
M
P
Register
Access
Reset Value
Section/Page
PTT—Port T Data Register
R/W
0x00
2.3.18/2-85
0x0241
PTIT—Port T Input Register
R
4
2.3.19/2-86
0x0242
DDRT—Port T Data Direction Register
R/W
0x00
2.3.20/2-87
0x0243
RDRT—Port T Reduced Drive Register
R/W
0x00
2.3.21/2-87
0x0244
PERT—Port T Pull Device Enable Register
R/W
0x00
2.3.22/2-88
0x0245
PPST—Port T Polarity Select Register
R/W
0x00
2.3.23/2-88
0x0246
PIM Reserved
R
0x00
2.3.24/2-89
0x0247
Port T Routing Register
R/W
0x00
2.3.25/2-89
0x0248
PTS—Port S Data Register
R/W
0x00
2.3.26/2-91
0x0249
PTIS—Port S Input Register
R
4
2.3.27/2-92
0x024A
DDRS—Port S Data Direction Register
R/W
0x00
2.3.28/2-93
0x024B
RDRS—Port S Reduced Drive Register
R/W
0x00
2.3.29/2-94
0x024C
PERS—Port S Pull Device Enable Register
R/W
0xFF
2.3.30/2-94
0x024D
PTPS—Port S Polarity Select Register
R/W
0x00
2.3.31/2-95
0x024E
WOMS—Port S Wired-Or Mode Register
R/W
0x00
2.3.32/2-95
0x024F
PIM Reserved
R
0x00
2.3.33/2-96
0x0250
PTM—Port M Data Register
R/W
0x00
2.3.34/2-96
0x0251
PTIM—Port M Input Register
R
4
2.3.35/2-98
0x0252
DDRM—Port M Data Direction Register
R/W
0x00
2.3.36/2-98
0x0253
RDRM—Port M Reduced Drive Register
R/W
0x00
2.3.37/2-99
0x0254
PERM—Port M Pull Device Enable Register
R/W
0x00
2.3.38/2-100
0x0255
PPSM—Port M Polarity Select Register
R/W
0x00
2.3.39/2-100
0x0256
WOMM—Port M Wired-Or Mode Register
R/W
0x00
2.3.40/2-101
0x0257
MODRR—Module Routing Register
R/W
0x00
2.3.41/2-101
0x0258
PTP—Port P Data Register
R/W
0x00
2.3.42/2-102
0x0259
PTIP—Port P Input Register
R
4
2.3.43/2-104
0x025A
DDRP—Port P Data Direction Register
R/W
0x00
2.3.44/2-105
0x025B
RDRP—Port P Reduced Drive Register
R/W
0x00
2.3.45/2-106
0x025C
PERP—Port P Pull Device Enable Register
R/W
0x00
2.3.46/2-106
0x025D
PTPP—Port P Polarity Select Register
R/W
0x00
2.3.47/2-107
0x025E
PIEP—Port P Interrupt Enable Register
R/W
0x00
2.3.48/2-107
0x025F
PIFP—Port P Interrupt Flag Register
R/W
0x00
2.3.49/2-108
S12XS Family Reference Manual, Rev. 1.10
66
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-2. Block Memory Map (continued)
Port
Offset or
Address
H
0x0260
J
AD
Register
Access
Reset Value
Section/Page
PTH—Port H Data Register
R/W
0x00
2.3.50/2-108
0x0261
PTIH—Port H Input Register
R
4
2.3.51/2-109
0x0262
DDRH—Port H Data Direction Register
R/W
0x00
2.3.52/2-109
0x0263
RDRH—Port H Reduced Drive Register
R/W
0x00
2.3.53/2-110
0x0264
PERH—Port H Pull Device Enable Register
R/W
0x00
2.3.54/2-110
0x0265
PPSH—Port H Polarity Select Register
R/W
0x00
2.3.55/2-111
0x0266
PIEH—Port H Interrupt Enable Register
R/W
0x00
2.3.56/2-111
0x0267
PIFH—Port H Interrupt Flag Register
R/W
0x00
2.3.57/2-112
0x0268
PTJ—Port J Data Register
R/W
0x00
2.3.58/2-112
0x0269
PTIJ—Port J Input Register
R
4
2.3.59/2-113
0x026A
DDRJ—Port J Data Direction Register
R/W
0x00
2.3.60/2-113
0x026B
RDRJ—Port J Reduced Drive Register
R/W
0x00
2.3.61/2-114
0x026C
PERJ—Port J Pull Device Enable Register
R/W
0xFF
2.3.62/2-114
0x026D
PPSJ—Port J Polarity Select Register
R/W
0x00
2.3.63/2-115
0x026E
PIEJ—Port J Interrupt Enable Register
R/W
0x00
2.3.64/2-115
0x026F
PIFJ—Port J Interrupt Flag Register
R/W
0x00
2.3.65/2-116
0x0270
PT0AD0—Port AD0 Data Register 0
R/W
0x00
2.3.66/2-116
0x0271
PT1AD0—Port AD0 Data Register 1
R/W
0x00
2.3.67/2-117
0x0272
DDR0AD0—Port AD0 Data Direction Register 0
R/W
0x00
2.3.68/2-117
0x0273
DDR1AD0—Port AD0 Data Direction Register 1
R/W
0x00
2.3.69/2-118
0x0274
RDR0AD0—Port AD0 Reduced Drive Register 0
R/W
0x00
2.3.70/2-118
0x0275
RDR1AD0—Port AD0 Reduced Drive Register 1
R/W
0x00
2.3.71/2-119
0x0276
PER0AD0—Port AD0 Pull Up Enable Register 0
R/W
0x00
2.3.72/2-119
0x0277
PER1AD0—Port AD0 Pull Up Enable Register 1
R/W
0x00
2.3.73/2-120
0x0278
:
0x027F
PIM Reserved
R
0x00
2.3.74/2-120
1
Write access not applicable for one or more register bits. Refer to register description.
Refer to memory map in SoC Guide to determine related module.
3 Mode dependent.
4 Read always returns logic level on pins.
2
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
67
Port Integration Module (S12XSPIMV1)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
DDRA7
DDRA6
DDRA5
DDRA4
DDRA3
DDRA2
DDRA1
DDRA0
DDRB7
DDRB6
DDRB5
DDRB4
DDRB3
DDRB2
DDRB1
DDRB0
0x0004
R
Reserved W
0
0
0
0
0
0
0
0
0x0005
R
Reserved W
0
0
0
0
0
0
0
0
0x0006
R
Reserved W
0
0
0
0
0
0
0
0
0x0007
R
Reserved W
0
0
0
0
0
0
0
0
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
DDRE7
DDRE6
DDRE5
DDRE4
DDRE3
DDRE2
0
0
PUPBE
PUPAE
RDPB
RDPA
0x0000
PORTA
R
W
0x0001
PORTB
W
0x0002
DDRA
W
0x0003
DDRB
0x0008
PORTE
0x0009
DDRE
R
R
R
W
R
W
R
W
0x000A R
0x000B W
Non-PIM
Address
Range
0x000C
PUCR
0x000D
RDRIV
R
W
R
W
0x000E– R
0x001B W
Non-PIM
Address
Range
Non-PIM Address Range
PUPKE
RDPK
BKPUE
0
0
PUPEE
0
RDPE
0
0
0
0
Non-PIM Address Range
= Unimplemented or Reserved
S12XS Family Reference Manual, Rev. 1.10
68
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Register
Name
0x001C R
ECLKCTL W
0x001D R
Reserved W
0x001E
IRQCR
W
0x001F
R
Reserved
R
Bit 7
6
5
4
3
2
1
Bit 0
NECLK
NCLKX2
DIV16
EDIV4
EDIV3
EDIV2
EDIV1
EDIV0
0
0
0
0
0
0
0
0
IRQE
IRQEN
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
0x0020– R
0x0031 W
Non-PIM
Address
Range
0x0032
PORTK
0x0033
DDRK
R
W
R
W
Non-PIM Address Range
PK7
DDRK7
0
0
PK5
PK4
PK3
PK2
PK1
PK0
DDRK5
DDRK4
DDRK3
DDRK2
DDRK1
DDRK0
0x0034– R
0x023F W
Non-PIM
Address
Range
0x0240
PTT
R
W
0x0241
PTIT
W
0x0242
DDRT
W
0x0243
RDRT
R
R
R
W
0x0244
PERT
R
W
0x0245
PPST
W
R
Non-PIM Address Range
PTT7
PTT6
PTT5
PTT4
PTT3
PTT2
PTT1
PTT0
PTIT7
PTIT6
PTIT5
PTIT4
PTIT3
PTIT2
PTIT1
PTIT0
DDRT7
DDRT6
DDRT5
DDRT4
DDRT3
DDRT2
DDRT1
DDRT0
RDRT7
RDRT6
RDRT5
RDRT4
RDRT3
RDRT2
RDRT1
RDRT0
PERT7
PERT6
PERT5
PERT4
PERT3
PERT2
PERT1
PERT0
PPST7
PPST6
PPST5
PPST4
PPST3
PPST2
PPST1
PPST0
= Unimplemented or Reserved
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
69
Port Integration Module (S12XSPIMV1)
Register
Name
0x0246
R
Reserved W
0x0247
PTTRR
W
0x0248
PTS
W
0x0249
PTIS
R
R
R
W
0x024B
RDRS
W
R
R
R
W
0x024D
PPSS
W
0x024E
WOMS
W
R
R
0x024F
R
Reserved W
0x0250
PTM
R
W
0x0251
PTIM
W
0x0252
DDRM
W
0x0253
RDRM
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
PTTRR7
PTTRR6
PTTRR5
PTTRR4
PTTRR2
PTTRR1
PTTRR0
PTS7
PTS6
PTS5
PTS4
PTS3
PTS2
PTS1
PTS0
PTIS7
PTIS6
PTIS5
PTIS4
PTIS3
PTIS2
PTIS1
PTIS0
DDRS7
DDRS6
DDRS5
DDRS4
DDRS3
DDRS2
DDRS1
DDRS0
RDRS7
RDRS6
RDRS5
RDRS4
RDRS3
RDRS2
RDRS1
RDRS0
PERS7
PERS6
PERS5
PERS4
PERS3
PERS2
PERS1
PERS0
PPSS7
PPSS6
PPSS5
PPSS4
PPSS3
PPSS2
PPSS1
PPSS0
WOMS7
WOMS6
WOMS5
WOMS4
WOMS3
WOMS2
WOMS1
WOMS0
0
0
0
0
0
0
0
0
PTM7
PTM6
PTM5
PTM4
PTM3
PTM2
PTM1
PTM0
PTIM7
PTIM6
PTIM5
PTIM4
PTIM3
PTIM2
PTIM1
PTIM0
DDRM7
DDRM6
DDRM5
DDRM4
DDRM3
DDRM2
DDRM1
DDRM0
RDRM7
RDRM6
RDRM5
RDRM4
RDRM3
RDRM2
RDRM1
RDRM0
PERM7
PERM6
PERM5
PERM4
PERM3
PERM2
PERM1
PERM0
PPSM7
PPSM6
PPSM5
PPSM4
PPSM3
PPSM2
PPSM1
PPSM0
0
W
0x024A
DDRS
0x024C
PERS
Bit 7
R
R
R
W
0x0254
PERM
R
W
0x0255
PPSM
W
R
= Unimplemented or Reserved
S12XS Family Reference Manual, Rev. 1.10
70
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Register
Name
0x0256
WOMM
R
W
0x0257
MODRR
W
0x0258
PTP
W
0x0259
PTIP
0x025A
DDRP
R
R
R
R
W
W
0x025C
PERP
W
R
R
R
W
0x025E
PIEP
W
0x025F
PIFP
W
0x0260
PTH
R
R
R
W
0x0261
PTIH
W
0x0262
DDRH
W
0x0263
RDRH
0x0264
PERH
6
5
4
3
2
1
Bit 0
WOMM7
WOMM6
WOMM5
WOMM4
WOMM3
WOMM2
WOMM1
WOMM0
MODRR7
MODRR6
0
0
0
0
PTP7
PTP6
PTP5
PTP4
PTP3
PTP2
PTP1
PTP0
PTIP7
PTIP6
PTIP5
PTIP4
PTIP3
PTIP2
PTIP1
PTIP0
DDRP7
DDRP6
DDRP5
DDRP4
DDRP3
DDRP2
DDRP1
DDRP0
RDRP7
RDRP6
RDRP5
RDRP4
RDRP3
RDRP2
RDRP1
RDRP0
PERP7
PERP6
PERP5
PERP4
PERP3
PERP2
PERP1
PERP0
PPSP7
PPSP6
PPSP5
PPSP4
PPSP3
PPSP2
PPSP1
PPSP0
PIEP7
PIEP6
PIEP5
PIEP4
PIEP3
PIEP2
PIEP1
PIEP0
PIFP7
PIFP6
PIFP5
PIFP4
PIFP3
PIFP2
PIFP1
PIFP0
PTH7
PTH6
PTH5
PTH4
PTH3
PTH2
PTH1
PTH0
PTIH7
PTIH6
PTIH5
PTIH4
PTIH3
PTIH2
PTIH1
PTIH0
DDRH7
DDRH6
DDRH5
DDRH4
DDRH3
DDRH2
DDRH1
DDRH0
RDRH7
RDRH6
RDRH5
RDRH4
RDRH3
RDRH2
RDRH1
RDRH0
PERH7
PERH6
PERH5
PERH4
PERH3
PERH2
PERH1
PERH0
0
MODRR4
W
0x025B
RDRP
0x025D
PPSP
Bit 7
R
R
R
W
R
W
= Unimplemented or Reserved
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
71
Port Integration Module (S12XSPIMV1)
Register
Name
0x0265
PPSH
R
W
0x0266
PIEH
W
0x0267
PIFH
W
0x0268
PTJ
R
R
R
W
0x0269
PTIJ
W
0x026A
DDRJ
W
0x026B
RDRJ
R
R
R
W
0x026C
PERJ
W
0x026D
PPSJ
W
0x026E
PIEJ
0x026F
PIFJ
R
R
R
W
R
W
0x0270
PT0AD0
R
W
0x0271
PT1AD0
W
R
Bit 7
6
5
4
3
2
1
Bit 0
PPSH7
PPSH6
PPSH5
PPSH4
PPSH3
PPSH2
PPSH1
PPSH0
PIEH7
PIEH6
PIEH5
PIEH4
PIEH3
PIEH2
PIEH1
PIEH0
PIFH7
PIFH6
PIFH5
PIFH4
PIFH3
PIFH2
PIFH1
PIFH0
PTJ7
PTJ6
0
0
0
0
PTJ1
PTJ0
PTIJ7
PTIJ6
0
0
0
0
PTIJ1
PTIJ0
DDRJ7
DDRJ6
0
0
0
0
DDRJ1
DDRJ0
RDRJ7
RDRJ6
0
0
0
0
RDRJ1
RDRJ0
PERJ7
PERJ6
0
0
0
0
PERJ1
PERJ0
PPSJ7
PPSJ6
0
0
0
0
PPSJ1
PPSJ0
PIEJ7
PIEJ6
0
0
0
0
PIEJ1
PIEJ0
PIFJ7
PIFJ6
0
0
0
0
PIFJ1
PIFJ0
PT0AD07
PT0AD06
PT0AD05
PT0AD04
PT0AD03
PT0AD02
PT0AD01
PT0AD00
PT1AD07
PT1AD06
PT1AD05
PT1AD04
PT1AD03
PT1AD02
PT1AD01
PT1AD00
0x0272
R
DDR0AD0 W DDR0AD07 DDR0AD06 DDR0AD05 DDR0AD04 DDR0AD03 DDR0AD02 DDR0AD01 DDR0AD00
0x0273
R
DDR1AD0 W DDR1AD07 DDR1AD06 DDR1AD05 DDR1AD04 DDR1AD03 DDR1AD02 DDR1AD01 DDR1AD00
0x0274
R
RDR0AD0 W RDR0AD07 RDR0AD06 RDR0AD05 RDR0AD04 RDR0AD03 RDR0AD02 RDR0AD01 RDR0AD00
= Unimplemented or Reserved
S12XS Family Reference Manual, Rev. 1.10
72
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
0x0275
R
RDR1AD0 W RDR1AD07 RDR1AD06 RDR1AD05 RDR1AD04 RDR1AD03 RDR1AD02 RDR1AD01 RDR1AD00
0x0276
R
PER0AD0 W PER0AD07
PER0AD06
PER0AD05
PER0AD04
PER0AD03
PER0AD02
PER0AD01
PER0AD00
0x0277
R
PER1AD0 W PER1AD07
PER1AD06
PER1AD05
PER1AD04
PER1AD03
PER1AD02
PER1AD01
PER1AD00
0x0278
R
Reserved W
0
0
0
0
0
0
0
0
0x0279
R
Reserved W
0
0
0
0
0
0
0
0
0x027A R
Reserved W
0
0
0
0
0
0
0
0
0x027B R
Reserved W
0
0
0
0
0
0
0
0
0x027C R
Reserved W
0
0
0
0
0
0
0
0
0x027D R
Reserved W
0
0
0
0
0
0
0
0
0x027E R
Reserved W
0
0
0
0
0
0
0
0
0x027F
R
Reserved W
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
2.3.2
Register Descriptions
The following table summarizes the effect of the various configuration bits, i.e. data direction (DDR),
output level (IO), reduced drive (RDR), pull enable (PE), pull select (PS) on the pin function and pull
device activity.
The configuration bit PS is used for two purposes:
1. Configure the sensitive interrupt edge (rising or falling), if interrupt enabled.
2. Select either a pull-up or pull-down device if PE is active.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
73
Port Integration Module (S12XSPIMV1)
Table 2-3. Pin Configuration Summary
1
2
DDR
IO
RDR
PE
PS1
IE2
0
x
x
0
x
0
Input
Disabled
Disabled
0
x
x
1
0
0
Input
Pull Up
Disabled
0
x
x
1
1
0
Input
Pull Down
Disabled
0
x
x
0
0
1
Input
Disabled
Falling edge
0
x
x
0
1
1
Input
Disabled
Rising edge
0
x
x
1
0
1
Input
Pull Up
Falling edge
0
x
x
1
1
1
Input
Pull Down
Rising edge
1
0
0
x
x
0
Output, full drive to 0
Disabled
Disabled
1
1
0
x
x
0
Output, full drive to 1
Disabled
Disabled
1
0
1
x
x
0
Output, reduced drive to 0
Disabled
Disabled
1
1
1
x
x
0
Output, reduced drive to 1
Disabled
Disabled
1
0
0
x
0
1
Output, full drive to 0
Disabled
Falling edge
1
1
0
x
1
1
Output, full drive to 1
Disabled
Rising edge
1
0
1
x
0
1
Output, reduced drive to 0
Disabled
Falling edge
1
1
1
x
1
1
Output, reduced drive to 1
Disabled
Rising edge
Function
Pull Device
Interrupt
Always “0” on Port A, B, E, K, and AD.
Applicable only on Port P, H, and J.
NOTE
All register bits in this module are completely synchronous to internal
clocks during a register read.
NOTE
Figures of port data registers also display the alternative functions if
applicable on the related pin as defined in Table . Names in brackets denote
the availability of the function when using a specific routing option.
NOTE
Figures of module routing registers also display the module instance or
module channel associated with the related routing bit.
S12XS Family Reference Manual, Rev. 1.10
74
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.3
Port A Data Register (PORTA)
Access: User read/write1
Address 0x0000 (PRR)
7
6
5
4
3
2
1
0
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-1. Port A Data Register (PORTA)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-4. PORTA Register Field Descriptions
Field
Description
7-0
PA
Port A general purpose input/output data—Data Register
The associated pin can be used as general purpose I/O. In general purpose output mode the register bit value is
driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
2.3.4
Port B Data Register (PORTB)
Access: User read/write1
Address 0x0001 (PRR)
7
6
5
4
3
2
1
0
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-2. Port B Data Register (PORTB)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-5. PORTB Register Field Descriptions
Field
Description
7-0
PB
Port B general purpose input/output data—Data Register
The associated pin can be used as general purpose I/O. In general purpose output mode the register bit value is
driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
75
Port Integration Module (S12XSPIMV1)
2.3.5
Port A Data Direction Register (DDRA)
Access: User read/write1
Address 0x0002 (PRR)
7
6
5
4
3
2
1
0
DDRA7
DDRA6
DDRA5
DDRA4
DDRA3
DDRA2
DDRA1
DDRA0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-3. Port A Data Direction Register (DDRA)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-6. DDRA Register Field Descriptions
Field
7-0
DDRA
Description
Port A Data Direction—
This bit determines whether the associated pin is an input or output.
1 Associated pin configured as output
0 Associated pin configured as input
2.3.6
Port B Data Direction Register (DDRB)
Access: User read/write1
Address 0x0003 (PRR)
7
6
5
4
3
2
1
0
DDRB7
DDRB6
DDRB5
DDRB4
DDRB3
DDRB2
DDRB1
DDRB0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-4. Port B Data Direction Register (DDRB)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-7. DDRB Register Field Descriptions
Field
7-0
DDRB
Description
Port B Data Direction—
This bit determines whether the associated pin is an input or output.
1 Associated pin configured as output
0 Associated pin configured as input
S12XS Family Reference Manual, Rev. 1.10
76
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.7
PIM Reserved Registers
Access: User read1
Address 0x0004 (PRR) to 0x0007 (PRR)
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 2-5. PIM Reserved Registers
1
Read: Always reads 0x00
Write: Unimplemented
2.3.8
Port E Data Register (PORTE)
Access: User read/write1
Address 0x0008 (PRR)
7
6
5
4
3
2
1
0
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
XCLKS
—
—
ECLK
—
—
IRQ
XIRQ
ECLKX2
—
—
—
—
—
—
—
0
0
0
0
0
0
—2
—2
R
W
Altern.
Function
Reset
= Unimplemented or Reserved
Figure 2-6. Port E Data Register (PORTE)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
2
These registers are reset to zero. Two bus clock cycles after reset release the register values are updated with the associated
pin values.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
77
Port Integration Module (S12XSPIMV1)
Table 2-8. PORTE Register Field Descriptions
Field
Description
7
PE
Port E general purpose input/output data—Data Register, ECLKX2 output, XCLKS input
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The ECLKX2 output function takes precedence over the general purpose I/O function if enabled.
• The external clock selection feature (XCLKS) is only active during RESET=0
6-5, 3-2
PE
Port E general purpose input/output data—Data Register
The associated pin can be used as general purpose I/O. In general purpose output mode the register bit value is
driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
4
PE
Port E general purpose input/output data—Data Register, ECLK output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The ECLK output function takes precedence over the general purpose I/O function if enabled.
1
PE
Port E general purpose input data and interrupt—Data Register, IRQ input.
This pin can be used as general purpose and IRQ input.
0
PE
Port E general purpose input data and interrupt—Data Register, XIRQ input.
This pin can be used as general purpose and XIRQ input.
2.3.9
Port E Data Direction Register (DDRE)
Access: User read/write1
Address 0x0009 (PRR)
7
6
5
4
3
2
DDRE7
DDRE6
DDRE5
DDRE4
DDRE3
DDRE2
0
0
0
0
0
0
R
1
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 2-7. Port E Data Direction Register (DDRE)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
S12XS Family Reference Manual, Rev. 1.10
78
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-9. DDRE Register Field Descriptions
Field
7-2
DDRE
Description
Port E Data Direction—
This bit determines whether the associated pin is an input or output.
1 Associated pin configured as output
0 Associated pin configured as input
2.3.10
Ports ABEK, BKGD pin Pull-up Control Register (PUCR)
Access: User read/write1
Address 0x000C (PRR)
7
6
PUPKE
BKPUE
1
1
5
R
4
0
3
2
0
0
PUPEE
1
0
PUPBE
PUPAE
0
0
W
Reset
0
1
0
0
= Unimplemented or Reserved
Figure 2-8. Ports ABEK, BKGD pin Pull-up Control Register (PUCR)
1
Read: Anytime in single-chip modes.
Write: Anytime, except BKPUE which is writable in Special Single-Chip Mode only.
Table 2-10. PUCR Register Field Descriptions
Field
Description
7
PUPKE
Port K Pull-up Enable—Enable pull-up devices on all port input pins
This bit configures whether a pull-up device is activated on all associated port input pins. If a pin is used as output
this bit has no effect.
1 Pull-up device enabled
0 Pull-up device disabled
6
BKPUE
BKGD pin pull-up Enable—Enable pull-up device on pin
This bit configures whether a pull-up device is activated, if the pin is used as input. If a pin is used as output this bit
has no effect.
1 Pull-up device enabled
0 Pull-up device disabled
4
PUPEE
Port E Pull-up Enable—Enable pull-up devices on all port input pins except pins 5 and 6
This bit configures whether a pull-up device is activated on all associated port input pins. If a pin is used as output
this bit has no effect.
Pins 5 and 6 have pull-down devices enabled only during reset. This bit has no effect on these pins.
1 Pull-up device enabled
0 Pull-up device disabled
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
79
Port Integration Module (S12XSPIMV1)
Table 2-10. PUCR Register Field Descriptions (continued)
Field
Description
1
PUPBE
Port B Pull-up Enable—Enable pull-up devices on all port input pins
This bit configures whether a pull-up device is activated on all associated port input pins. If a pin is used as output
this bit has no effect.
1 Pull-up device enabled
0 Pull-up device disabled
0
PUPAE
Port A Pull-up Enable—Enable pull-up devices on all port input pins
This bit configures whether a pull-up device is activated on all associated port input pins. If a pin is used as output
this bit has no effect.
1 Pull-up device enabled
0 Pull-up device disabled
2.3.11
Ports ABEK Reduced Drive Register (RDRIV)
Access: User read/write1
Address 0x000D (PRR)
7
R
6
5
0
0
RDPK
4
3
2
0
0
RDPE
1
0
RDPB
RDPA
0
0
W
Reset
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 2-9. Ports ABEK Reduced Drive Register (RDRIV)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
This register is used to select reduced drive for the pins associated with ports A, B, E, and K. If enabled,
the pins drive at approx. 1/5 of the full drive strength.
Table 2-11. RDRIV Register Field Descriptions
Field
Description
7
RDPK
Port K reduced drive—Select reduced drive for output port
This bit configures the drive strength of all associated port output pins as either full or reduced. If a pin is used as
input this bit has no effect. The reduced drive function is independent of which function is being used on a particular
pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
4
RDPE
Port E reduced drive—Select reduced drive for output port
This bit configures the drive strength of all associated port output pins as either full or reduced. If a pin is used as
input this bit has no effect. The reduced drive function is independent of which function is being used on a particular
pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
S12XS Family Reference Manual, Rev. 1.10
80
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-11. RDRIV Register Field Descriptions (continued)
Field
Description
1
RDPB
Port B reduced drive—Select reduced drive for output port
This bit configures the drive strength of all associated port output pins as either full or reduced. If a pin is used as
input this bit has no effect. The reduced drive function is independent of which function is being used on a particular
pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
0
RDPA
Port A reduced drive—Select reduced drive for output port
This bit configures the drive strength of all associated port output pins as either full or reduced. If a pin is used as
input this bit has no effect. The reduced drive function is independent of which function is being used on a particular
pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
2.3.12
ECLK Control Register (ECLKCTL)
Access: User read/write1
Address 0x001C (PRR)
7
6
5
4
3
2
1
0
NECLK
NCLKX2
DIV16
EDIV4
EDIV3
EDIV2
EDIV1
EDIV0
Reset:
Mode
Dependent
1
0
0
0
0
0
0
Special
single-chip
0
1
0
0
0
0
0
0
Normal
single-chip
1
1
0
0
0
0
0
0
R
W
= Unimplemented or Reserved
Figure 2-10. ECLK Control Register (ECLKCTL)
1
Read: Anytime.
Write: Anytime.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
81
Port Integration Module (S12XSPIMV1)
Table 2-12. ECLKCTL Register Field Descriptions
Field
Description
7
NECLK
No ECLK—Disable ECLK output
This bit controls the availability of a free-running clock on the ECLK pin. This clock has a fixed rate equivalent to the
internal bus clock.
1 ECLK disabled
0 ECLK enabled
6
NCLKX2
No ECLKX2—Disable ECLKX2 output
This bit controls the availability of a free-running clock on the ECLKX2 pin. This clock has a fixed rate of twice the
internal bus clock.
1 ECLKX2 disabled
0 ECLKX2 enabled
5
DIV16
Free-running ECLK predivider—Divide by 16
This bit enables a divide-by-16 stage on the selected EDIV rate.
1 Divider enabled: ECLK rate = EDIV rate divided by 16
0 Divider disabled: ECLK rate = EDIV rate
4-0
EDIV
Free-running ECLK Divider—Configure ECLK rate
These bits determine the rate of the free-running clock on the ECLK pin.
00000 ECLK rate = bus clock rate
00001 ECLK rate = bus clock rate divided by 2
00010 ECLK rate = bus clock rate divided by 3, ...
11111 ECLK rate = bus clock rate divided by 32
2.3.13
PIM Reserved Register
Access: User read1
Address 0x001D (PRR)
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 2-11. PIM Reserved Register
1
Read: Always reads 0x00
Write: Unimplemented
S12XS Family Reference Manual, Rev. 1.10
82
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.14
IRQ Control Register (IRQCR)
Access: User read/write1
Address 0x001E
7
6
IRQE
IRQEN
0
1
R
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 2-12. IRQ Control Register (IRQCR)
1
Read: See individual bit descriptions below.
Write: See individual bit descriptions below.
Table 2-13. IRQCR Register Field Descriptions
Field
7
IRQE
Description
IRQ select edge sensitive only—
Special mode: Read or write anytime.
Normal mode: Read anytime, write once.
1 IRQ configured to respond only to falling edges. Falling edges on the IRQ pin will be detected anytime IRQE=1
and will be cleared only upon a reset or the servicing of the IRQ interrupt.
0 IRQ configured for low level recognition.
6
IRQEN
IRQ enable—
Read or write anytime.
1 IRQ pin is connected to interrupt logic.
0 IRQ pin is disconnected from interrupt logic.
2.3.15
PIM Reserved Register PIMTEST1
This register is reserved for factory testing of the PIM module and is not available in normal operation.
Writing to this register when in special modes can alter the pin functionality.
Access: User read1
Address 0x001F
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 2-13. PIM Reserved Register
1. Implementation pim_xe.01.01 and later
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
83
Port Integration Module (S12XSPIMV1)
1
Read: Always reads 0x00
Write: Unimplemented
2.3.16
Port K Data Register (PORTK)
Access: User read/write1
Address 0x0032 (PRR)
7
R
6
5
4
3
2
1
0
PK5
PK4
PK3
PK2
PK1
PK0
0
0
0
0
0
0
0
PK7
W
Reset
0
0
Figure 2-14. Port K Data Register (PORTK)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-14. PORTK Register Field Descriptions
Field
Description
7,5-0
PK
Port K general purpose input/output data—Data Register
The associated pin can be used as general purpose I/O. In general purpose output mode the register bit value is
driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
2.3.17
Port K Data Direction Register (DDRK)
Access: User read/write1
Address 0x0033 (PRR)
7
R
6
5
4
3
2
1
0
DDRK5
DDRK4
DDRK3
DDRK2
DDRK1
DDRK0
0
0
0
0
0
0
0
DDRK7
W
Reset
0
0
Figure 2-15. Port K Data Direction Register (DDRK)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
S12XS Family Reference Manual, Rev. 1.10
84
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-15. DDRK Register Field Descriptions
Field
7,5-0
DDRK
Description
Port K Data Direction—
This bit determines whether the associated pin is an input or output.
1 Associated pin configured as output
0 Associated pin configured as input
2.3.18
Port T Data Register (PTT)
Access: User read/write1
Address 0x0240
7
6
5
4
3
2
1
0
PTT7
PTT6
PTT5
PTT4
PTT3
PTT2
PTT1
PTT0
IOC7
IOC6
IOC5
IOC4
IOC3
IOC2
IOC1
IOC0
(PWM7)
(PWM6)
(PWM5)
(PWM4)
—
—
—
—
—
—
VREG_API
—
—
—
—
—
0
0
0
0
0
0
0
0
R
W
Altern.
Function
Reset
Figure 2-16. Port T Data Register (PTT)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-16. PTT Register Field Descriptions
Field
Description
7-6, 4
PTT
Port T general purpose input/output data—Data Register, TIM output, routed PWM output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The TIM output function takes precedence over the routed PWM and the general purpose I/O function if the
related channel is enabled.
• The routed PWM function takes precedence over the general purpose I/O function if the related channel is
enabled.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
85
Port Integration Module (S12XSPIMV1)
Table 2-16. PTT Register Field Descriptions (continued)
Field
Description
5
PTT
Port T general purpose input/output data—Data Register, TIM output, routed PWM output, VREG_API output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The TIM output function takes precedence over the routed PWM, VREG_API function and the general purpose
I/O function if the related channel is enabled.
• The routed PWM function takes precedence over VREG_API and the general purpose I/O function if the related
channel is enabled.
• The VREG_API takes precedence over the general purpose I/O function if enabled.
3-0
PTT
Port T general purpose input/output data—Data Register, TIM output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The TIM output function takes precedence over the general purpose I/O function if the related channel is enabled.
2.3.19
Port T Input Register (PTIT)
Access: User read1
Address 0x0241
R
7
6
5
4
3
2
1
0
PTIT7
PTIT6
PTIT5
PTIT4
PTIT3
PTIT2
PTIT1
PTIT0
u
u
u
u
u
u
u
u
W
Reset
= Unimplemented or Reserved
u = Unaffected by reset
Figure 2-17. Port T Input Register (PTIT)
1
Read: Anytime.
Write:Never, writes to this register have no effect.
Table 2-17. PTIT Register Field Descriptions
Field
Description
7-0
PTIT
Port T input data—
A read always returns the buffered input state of the associated pin. It can be used to detect overload or short circuit
conditions on output pins.
S12XS Family Reference Manual, Rev. 1.10
86
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.20
Port T Data Direction Register (DDRT)
Access: User read/write1
Address 0x0242
7
6
5
4
3
2
1
0
DDRT7
DDRT6
DDRT5
DDRT4
DDRT3
DDRT2
DDRT1
DDRT0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-18. Port T Data Direction Register (DDRT)
1
Read: Anytime.
Write: Anytime.
Table 2-18. DDRT Register Field Descriptions
Field
Description
7-6, 4
DDRT
Port T data direction—
This bit determines whether the pin is an input or output.
The TIM forces the I/O state to be an output for a timer port associated with an enabled output compare. Else the
routed PWM forces the I/O state to be an output for an enabled channel. In these cases the data direction bit will not
change.
1 Associated pin configured as output
0 Associated pin configured as input
5
DDRT
Port T data direction—
This bit determines whether the pin is an input or output.
The TIM forces the I/O state to be an output for a timer port associated with an enabled output compare. Else the
routed PWM forces the I/O state to be an output for an enabled channel. Else the VREG_API forces the I/O state to
be an output if enabled. In these cases the data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
3-0
DDRT
Port T data direction—
This bit determines whether the pin is an input or output.
The TIM forces the I/O state to be an output for a timer port associated with an enabled output compare. In this case
the data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
2.3.21
Port T Reduced Drive Register (RDRT)
Access: User read/write1
Address 0x0243
7
6
5
4
3
2
1
0
RDRT7
RDRT6
RDRT5
RDRT4
RDRT3
RDRT2
RDRT1
RDRT0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-19. Port T Reduced Drive Register (RDRT)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
87
Port Integration Module (S12XSPIMV1)
1
Read: Anytime.
Write: Anytime.
Table 2-19. RDRT Register Field Descriptions
Field
Description
7-0
RDRT
Port T reduced drive—Select reduced drive for output pin
This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
2.3.22
Port T Pull Device Enable Register (PERT)
Access: User read/write1
Address 0x0244
7
6
5
4
3
2
1
0
PERT7
PERT6
PERT5
PERT4
PERT3
PERT2
PERT1
PERT0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-20. Port T Pull Device Enable Register (PERT)
1
Read: Anytime.
Write: Anytime.
Table 2-20. PERT Register Field Descriptions
Field
Description
7-0
PERT
Port T pull device enable—Enable pull device on input pin
This bit controls whether a pull device on the associated port input pin is active. If a pin is used as output this bit has
no effect. The polarity is selected by the related polarity select register bit.
1 Pull device enabled
0 Pull device disabled
2.3.23
Port T Polarity Select Register (PPST)
Access: User read/write1
Address 0x0245
7
6
5
4
3
2
1
0
PPST7
PPST6
PPST5
PPST4
PPST3
PPST2
PPST1
PPST0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-21. Port T Polarity Select Register (PPST)
1
Read: Anytime.
Write: Anytime.
S12XS Family Reference Manual, Rev. 1.10
88
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-21. PPST Register Field Descriptions
Field
7-0
PPST
Description
Port T pull device select—Configure pull device polarity on input pin
This bit selects a pull-up or a pull-down device if enabled on the associated port input pin.
1 A pull-down device selected
0 A pull-up device selected
2.3.24
PIM Reserved Register
Access: User read1
Address 0x0246
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 2-22. PIM Reserved Register
1
Read: Always reads 0x00
Write: Unimplemented
2.3.25
Port T Routing Register (PTTRR)
Access: User read1
Address 0x0247
7
6
5
4
PTTRR7
PTTRR6
PTTRR5
PTTRR4
PWM7
PWM6
PWM5
PWM4
0
0
0
0
R
3
2
1
0
PTTRR2
PTTRR1
PTTRR0
—
IOC2
IOC1
IOC0
0
0
0
0
0
W
Routing
Option
Reset
= Unimplemented or Reserved
Figure 2-23. Port T Routing Register (PTTRR)
1
Read: Anytime.
Write: Anytime.
This register configures the re-routing of PWM and TIM channels on alternative pins.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
89
Port Integration Module (S12XSPIMV1)
Table 2-22. PTTRR Register Field Descriptions
Field
7
PTTRR
Description
Port T peripheral routing—
This register controls the routing of PWM channel 7.
1 PWM7 routed to PT7
0 PWM7 routed to PP7
6
PTTRR
Port T peripheral routing—
This register controls the routing of PWM channel 6.
1 PWM6 routed to PT6
0 PWM6 routed to PP6
5
PTTRR
Port T peripheral routing—
This register controls the routing of PWM channel 5.
1 PWM5 routed to PT5
0 PWM5 routed to PP5
4
PTTRR
Port T peripheral routing—
This register controls the routing of PWM channel 4.
1 PWM4 routed to PT4
0 PWM4 routed to PP4
2
PTTRR
Port T peripheral routing—
This register controls the routing of TIM channel 2.
1 IOC2 routed to PP2
0 IOC2 routed to PT2
1
PTTRR
Port T peripheral routing—
This register controls the routing of TIM channel 1.
1 IOC1 routed to PP1
0 IOC1 routed to PT1
0
PTTRR
Port T peripheral routing—
This register controls the routing of TIM channel 0.
1 IOC0 routed to PP0
0 IOC0 routed to PT0
S12XS Family Reference Manual, Rev. 1.10
90
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.26
Port S Data Register (PTS)
Access: User read/write1
Address 0x0248
7
6
5
4
3
2
1
0
PTS7
PTS6
PTS5
PTS4
PTS3
PTS2
PTS1
PTS0
SS0
SCK0
MOSI0
MISO0
TXD1
RXD1
TXD0
RXD0
0
0
0
0
0
0
0
0
R
W
Altern.
Function
Reset
Figure 2-24. Port S Data Register (PTS)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-23. PTS Register Field Descriptions
Field
Description
7
PTS
Port S general purpose input/output data—Data Register, SPI0 SS input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SPI0 function takes precedence over the general purpose I/O function if enabled.
6
PTS
Port S general purpose input/output data—Data Register, SPI0 SCK input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SPI0 function takes precedence over the general purpose I/O function if enabled.
5
PTS
Port S general purpose input/output data—Data Register, SPI0 MOSI input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SPI0 function takes precedence over the general purpose I/O function if enabled.
4
PTS
Port S general purpose input/output data—Data Register, SPI0 MISO input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SPI0 function takes precedence over the general purpose I/O function if enabled.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
91
Port Integration Module (S12XSPIMV1)
Table 2-23. PTS Register Field Descriptions (continued)
Field
Description
3
PTS
Port S general purpose input/output data—Data Register, SCI1 TXD output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SCI1 function takes precedence over the general purpose I/O function if enabled.
2
PTS
Port S general purpose input/output data—Data Register, SCI1 RXD input
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SCI1 function takes precedence over the general purpose I/O function if enabled.
1
PTS
Port S general purpose input/output data—Data Register, SCI0 TXD output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SCI0 function takes precedence over the general purpose I/O function if enabled.
0
PTS
Port S general purpose input/output data—Data Register, SCI0 RXD input
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SCI0 function takes precedence over the general purpose I/O function if enabled.
2.3.27
Port S Input Register (PTIS)
Access: User read1
Address 0x0249
R
7
6
5
4
3
2
1
0
PTIS7
PTIS6
PTIS5
PTIS4
PTIS3
PTIS2
PTIS1
PTIS0
u
u
u
u
u
u
u
u
W
Reset
= Unimplemented or Reserved
u = Unaffected by reset
Figure 2-25. Port S Input Register (PTIS)
1
Read: Anytime.
Write:Never, writes to this register have no effect.
S12XS Family Reference Manual, Rev. 1.10
92
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-24. PTIS Register Field Descriptions
Field
Description
7-0
PTIS
Port S input data—
A read always returns the buffered input state of the associated pin. It can be used to detect overload or short circuit
conditions on output pins.
2.3.28
Port S Data Direction Register (DDRS)
Access: User read/write1
Address 0x0249
7
6
5
4
3
2
1
0
DDRS7
DDRS6
DDRS5
DDRS4
DDRS3
DDRS2
DDRS1
DDRS0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-26. Port S Data Direction Register (DDRS)
1
Read: Anytime.
Write: Anytime.
Table 2-25. DDRS Register Field Descriptions
Field
Description
7-4
DDRS
Port S data direction—
This bit determines whether the associated pin is an input or output.
Depending on the configuration of the enabled SPI0 the I/O state will be forced to be input or output. In this case the
data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
3-2
DDRS
Port S data direction—
This bit determines whether the associated pin is an input or output.
Depending on the configuration of the enabled SCI1 the I/O state will be forced to be input or output. In this case the
data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
1-0
DDRS
Port S data direction—
This bit determines whether the associated pin is an input or output.
Depending on the configuration of the enabled SCI0 the I/O state will be forced to be input or output. In this case the
data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
93
Port Integration Module (S12XSPIMV1)
2.3.29
Port S Reduced Drive Register (RDRS)
Access: User read/write1
Address 0x024A
7
6
5
4
3
2
1
0
RDRS7
RDRS6
RDRS5
RDRS4
RDRS3
RDRS2
RDRS1
RDRS0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-27. Port S Reduced Drive Register (RDRS)
1
Read: Anytime.
Write: Anytime.
Table 2-26. RDRS Register Field Descriptions
Field
Description
7-0
RDRS
Port S reduced drive—Select reduced drive for output pin
This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
2.3.30
Port S Pull Device Enable Register (PERS)
Access: User read/write1
Address 0x024B
7
6
5
4
3
2
1
0
PERS7
PERS6
PERS5
PERS4
PERS3
PERS2
PERS1
PERS0
1
1
1
1
1
1
1
1
R
W
Reset
Figure 2-28. Port S Pull Device Enable Register (PERS)
1
Read: Anytime.
Write: Anytime.
Table 2-27. PERS Register Field Descriptions
Field
Description
7-0
PERS
Port S pull device enable—Enable pull device on input pin or wired-or output pin
This bit controls whether a pull device on the associated port input pin is active. If a pin is used as output this bit has
only effect if used in wired-or mode. The polarity is selected by the related polarity select register bit.
1 Pull device enabled
0 Pull device disabled
S12XS Family Reference Manual, Rev. 1.10
94
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.31
Port S Polarity Select Register (PPSS)
Access: User read/write1
Address 0x024C
7
6
5
4
3
2
1
0
PPSS7
PPSS6
PPSS5
PPSS4
PPSS3
PPSS2
PPSS1
PPSS0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-29. Port S Polarity Select Register (PPSS)
1
Read: Anytime.
Write: Anytime.
Table 2-28. PPSS Register Field Descriptions
Field
7-0
PPSS
Description
Port S pull device select—Configure pull device polarity on input pin
This bit selects a pull-up or a pull-down device if enabled on the associated port input pin.
1 A pull-down device selected
0 A pull-up device selected
2.3.32
Port S Wired-Or Mode Register (WOMS)
Access: User read/write1
Address 0x024C
7
6
5
4
3
2
1
0
WOMS7
WOMS6
WOMS5
WOMS4
WOMS3
WOMS2
WOMS1
WOMS0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-30. Port S Wired-Or Mode Register (WOMS)
1
Read: Anytime.
Write: Anytime.
Table 2-29. WOMS Register Field Descriptions
Field
Description
7-0
WOMS
Port S wired-or mode—Enable open-drain functionality on output pin
This bit configures an output pin as wired-or (open-drain) or push-pull independent of the function used on the pins.
In wired-or mode a logic “0” is driven active low while a logic “1” remains undriven. This allows a multipoint
connection of several serial modules. The bit has no influence on pins used as input.
1 Output buffer operates as open-drain output.
0 Output buffer operates as push-pull output.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
95
Port Integration Module (S12XSPIMV1)
2.3.33
PIM Reserved Register
Access: User read1
Address 0x024F
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
u = Unaffected by reset
Figure 2-31. PIM Reserved Register
1
Read: Always reads 0x00
Write: Unimplemented
2.3.34
Port M Data Register (PTM)
Access: User read/write1
Address 0x0250
7
6
5
4
3
2
1
0
PTM7
PTM6
PTM5
PTM4
PTM3
PTM2
PTM1
PTM0
—
—
(SCK0)
(MOSI0)
(SS0)
(MISO0)
TXCAN0
RXCAN0
—
—
—
—
—
—
(TXD1)
(RXD1)
0
0
0
0
0
0
0
0
R
W
Altern.
Function
Reset
Figure 2-32. Port M Data Register (PTM)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-30. PTM Register Field Descriptions
Field
Description
7-6
PTM
Port M general purpose input/output data—Data Register
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
5
PTM
Port M general purpose input/output data—Data Register, routed SPI0 SCK input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SPI0 function takes precedence over the general purpose I/O function if enabled.
S12XS Family Reference Manual, Rev. 1.10
96
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-30. PTM Register Field Descriptions (continued)
Field
Description
4
PTM
Port M general purpose input/output data—Data Register, routed SPI0 MOSI input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SPI0 function takes precedence over the general purpose I/O function if enabled.
3
PTM
Port M general purpose input/output data—Data Register, routed SPI0 SS input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SPI0 function takes precedence over the general purpose I/O function if enabled.
2
PTM
Port M general purpose input/output data—Data Register, routed SPI0 MISO input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The SPI0 function takes precedence over the general purpose I/O function if enabled.
1
PTM
Port M general purpose input/output data—Data Register, CAN0 TXCAN output, SCI1 TXD output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The CAN0 function takes precedence over the general purpose I/O function if enabled.
• The SCI1 function takes precedence over the general purpose I/O function if enabled.
0
PTM
Port M general purpose input/output data—Data Register, CAN0 RXCAN input, SCI1 RXD input
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The CAN0 function takes precedence over the general purpose I/O function if enabled.
• The SCI1 function takes precedence over the general purpose I/O function if enabled.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
97
Port Integration Module (S12XSPIMV1)
2.3.35
Port M Input Register (PTIM)
Access: User read1
Address 0x0251
R
7
6
5
4
3
2
1
0
PTIM7
PTIM6
PTIM5
PTIM4
PTIM3
PTIM2
PTIM1
PTIM0
u
u
u
u
u
u
u
u
W
Reset
= Unimplemented or Reserved
u = Unaffected by reset
Figure 2-33. Port M Input Register (PTIM)
1
Read: Anytime.
Write:Never, writes to this register have no effect.
Table 2-31. PTIM Register Field Descriptions
Field
Description
7-0
PTIM
Port M input data—
A read always returns the buffered input state of the associated pin. It can be used to detect overload or short circuit
conditions on output pins.
2.3.36
Port M Data Direction Register (DDRM)
Access: User read/write1
Address 0x0252
7
6
5
4
3
2
1
0
DDRM7
DDRM6
DDRM5
DDRM4
DDRM3
DDRM2
DDRM1
DDRM0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-34. Port M Data Direction Register (DDRM)
1
Read: Anytime.
Write: Anytime.
S12XS Family Reference Manual, Rev. 1.10
98
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-32. DDRM Register Field Descriptions
Field
7-6
DDRM
Description
Port M data direction—
This bit determines whether the associated pin is an input or output.
1 Associated pin configured as output
0 Associated pin configured as input
5-2
DDRM
Port M data direction—
This bit determines whether the associated pin is an input or output.
Depending on the configuration of the enabled SPI0 the I/O state will be forced to be input or output. In this case the
data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
1
DDRM
Port M data direction—
This bit determines whether the associated pin is an input or output.
The enabled CAN0 or SCI1 forces the I/O state to be an output. In this case the data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
0
DDRM
Port M data direction—
This bit determines whether the associated pin is an input or output.
The enabled CAN0 or SCI1 forces the I/O state to be an input. In this case the data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
2.3.37
Port M Reduced Drive Register (RDRM)
Access: User read/write1
Address 0x0253
7
6
5
4
3
2
1
0
RDRM7
RDRM6
RDRM5
RDRM4
RDRM3
RDRM2
RDRM1
RDRM0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-35. Port M Reduced Drive Register (RDRM)
1
Read: Anytime.
Write: Anytime.
Table 2-33. RDRM Register Field Descriptions
Field
Description
7-0
RDRM
Port M reduced drive—Select reduced drive for output pin
This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
99
Port Integration Module (S12XSPIMV1)
2.3.38
Port M Pull Device Enable Register (PERM)
Access: User read/write1
Address 0x0254
7
6
5
4
3
2
1
0
PERM7
PERM6
PERM5
PERM4
PERM3
PERM2
PERM1
PERM0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-36. Port M Pull Device Enable Register (PERM)
1
Read: Anytime.
Write: Anytime.
Table 2-34. PERM Register Field Descriptions
Field
Description
7-0
PERM
Port M pull device enable—Enable pull device on input pin or wired-or output pin
This bit controls whether a pull device on the associated port input pin is active. If a pin is used as output this bit has
only effect if used in wired-or mode. The polarity is selected by the related polarity select register bit.
1 Pull device enabled
0 Pull device disabled
2.3.39
Port M Polarity Select Register (PPSM)
Access: User read/write1
Address 0x0255
7
6
5
4
3
2
1
0
PPSM7
PPSM6
PPSM5
PPSM4
PPSM3
PPSM2
PPSM1
PPSM0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-37. Port M Polarity Select Register (PPSM)
1
Read: Anytime.
Write: Anytime.
Table 2-35. PPSM Register Field Descriptions
Field
7-0
PPSM
Description
Port M pull device select—Configure pull device polarity on input pin
This bit selects a pull-up or a pull-down device if enabled on the associated port input pin.
If CAN0 is active the selection of a pull-down device on the RXCAN input will have no effect.
1 A pull-down device selected
0 A pull-up device selected
S12XS Family Reference Manual, Rev. 1.10
100
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.40
Port M Wired-Or Mode Register (WOMM)
Access: User read/write1
Address 0x0256
7
6
5
4
3
2
1
0
WOMM7
WOMM6
WOMM5
WOMM4
WOMM3
WOMM2
WOMM1
WOMM0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-38. Port M Wired-Or Mode Register (WOMM)
1
Read: Anytime.
Write: Anytime.
Table 2-36. WOMM Register Field Descriptions
Field
Description
7-0
WOMM
Port M wired-or mode—Enable open-drain functionality on output pin
This bit configures an output pin as wired-or (open-drain) or push-pull independent of the function used on the pins.
In wired-or mode a logic “0” is driven active low while a logic “1” remains undriven. This allows a multipoint
connection of several serial modules. The bit has no influence on pins used as input.
1 Output buffer operates as open-drain output.
0 Output buffer operates as push-pull output.
2.3.41
Module Routing Register (MODRR)
Access: User read/write1
Address 0x0257
7
6
5
MODRR7
MODRR6
SCI1
SCI1
—
0
0
0
R
4
3
2
1
0
0
0
0
0
SPI0
—
—
—
—
0
0
0
0
0
0
MODRR4
W
Routing
Option
Reset
= Unimplemented or Reserved
Figure 2-39. Module Routing Register (MODRR)
1
Read: Anytime.
Write: Anytime.
This register configures the re-routing of SCI1 and SPI0 on alternative ports.
Table 2-37. SCI1 Routing
MODRRx
7
6
Related Pins
TXD
RXD
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
101
Port Integration Module (S12XSPIMV1)
Table 2-37. SCI1 Routing
MODRRx
Related Pins
0
0
PS3
PS2
0
1
PP2
PP0
1
0
PM1
PM0
1
1
Reserved1
Reserved1
1
Defaults to reset value
Table 2-38. SPI0 Routing
MODRRx
4
2.3.42
Related Pins
MISO0
MOSI0
SCK0
SS0
0
PS4
PS5
PS6
PS7
1
PM2
PM4
PM5
PM3
Port P Data Register (PTP)
Access: User read/write1
Address 0x0258
7
6
5
4
3
2
1
0
PTP7
PTP6
PTP5
PTP4
PTP3
PTP2
PTP1
PTP0
PWM7
PWM6
PWM5
PWM4
PWM3
PWM2
PWM1
PWM0
—
—
—
—
—
(IOC2)
(IOC1)
(IOC0)
—
—
—
—
—
(TXD1)
—
(RXD1)
0
0
0
0
0
0
0
0
R
W
Altern.
Function
Reset
Figure 2-40. Port P Data Register (PTP)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
S12XS Family Reference Manual, Rev. 1.10
102
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Table 2-39. PTP Register Field Descriptions
Field
Description
7
PTP
Port P general purpose input/output data—Data Register, PWM input/output, pin interrupt input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The PWM function takes precedence over the general purpose I/O function if the related channel or the
emergency shut-down feature is enabled.
• Pin interrupts can be generated if enabled in input or output mode.
6-3
PTP
Port P general purpose input/output data—Data Register, PWM output, pin interrupt input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The PWM function takes precedence over the general purpose I/O function if the related channel is enabled.
• Pin interrupts can be generated if enabled in input or output mode.
2
PTP
Port P general purpose input/output data—Data Register, PWM output, routed TIM output, routed SCI1 TXD
output, pin interrupt input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The PWM function takes precedence over the TIM, SCI1 and general purpose I/O function if the related channel
is enabled.
• The TIM function takes precedence over SCI1 and the general purpose I/O function if the related channel is
enabled.
• The SCI1 function takes precedence over the general purpose I/O function if enabled.
• Pin interrupts can be generated if enabled in input or output mode.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
103
Port Integration Module (S12XSPIMV1)
Table 2-39. PTP Register Field Descriptions (continued)
Field
Description
1
PTP
Port P general purpose input/output data—Data Register, PWM output, routed TIM output, pin interrupt
input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The PWM function takes precedence over the TIM and general purpose I/O function if the related channel is
enabled.
• The TIM function takes precedence over the general purpose I/O function if the related channel is enabled.
• Pin interrupts can be generated if enabled in input or output mode.
0
PTP
Port P general purpose input/output data—Data Register, PWM output, routed TIM output, routed SCI1 RXD
output, pin interrupt input/output
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• The PWM function takes precedence over the TIM, SCI1 and general purpose I/O function if the related channel
is enabled.
• The TIM function takes precedence over SCI1 and the general purpose I/O function if the related channel is
enabled.
• The SCI1 function takes precedence over the general purpose I/O function if enabled.
• Pin interrupts can be generated if enabled in input or output mode.
2.3.43
Port P Input Register (PTIP)
Access: User read1
Address 0x0259
R
7
6
5
4
3
2
1
0
PTIP7
PTIP6
PTIP5
PTIP4
PTIP3
PTIP2
PTIP1
PTIP0
u
u
u
u
u
u
u
u
W
Reset
= Unimplemented or Reserved
u = Unaffected by reset
Figure 2-41. Port P Input Register (PTIP)
1
Read: Anytime.
Write:Never, writes to this register have no effect.
Table 2-40. PTIP Register Field Descriptions
Field
Description
7-0
PTIP
Port P input data—
A read always returns the buffered input state of the associated pin. It can be used to detect overload or short circuit
conditions on output pins.
S12XS Family Reference Manual, Rev. 1.10
104
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.44
Port P Data Direction Register (DDRP)
Access: User read/write1
Address 0x025A
7
6
5
4
3
2
1
0
DDRP7
DDRP6
DDRP5
DDRP4
DDRP3
DDRP2
DDRP1
DDRP0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-42. Port P Data Direction Register (DDRP)
1
Read: Anytime.
Write: Anytime.
Table 2-41. DDRP Register Field Descriptions
Field
Description
7
DDRP
Port P data direction—
This bit determines whether the associated pin is an input or output.
The PWM forces the I/O state to be an output for an enabled channel. If the PWM shutdown feature is enabled this
pin is forced to be an input. In this case the data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
6-3
DDRP
Port P data direction—
This bit determines whether the associated pin is an input or output.
The PWM forces the I/O state to be an output for an enabled channel. In this case the data direction bit will not
change.
1 Associated pin configured as output
0 Associated pin configured as input
2,0
DDRP
Port P data direction—
This bit determines whether the associated pin is an input or output.
The PWM forces the I/O state to be an output for an enabled channel. Else the TIM forces the I/O state to be an
output for a timer port associated with an enabled output compare. Else depending on the configuration of the
enabled SCI the I/O state will be forced to be input or output. In this case the data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
1
DDRP
Port P data direction—
This bit determines whether the associated pin is an input or output.
The PWM forces the I/O state to be an output for an enabled channel. Else the TIM forces the I/O state to be an
output for a timer port associated with an enabled output compare. In this case the data direction bit will not change.
1 Associated pin configured as output
0 Associated pin configured as input
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
105
Port Integration Module (S12XSPIMV1)
2.3.45
Port P Reduced Drive Register (RDRP)
Access: User read/write1
Address 0x025B
7
6
5
4
3
2
1
0
RDRP7
RDRP6
RDRP5
RDRP4
RDRP3
RDRP2
RDRP1
RDRP0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-43. Port P Reduced Drive Register (RDRP)
1
Read: Anytime.
Write: Anytime.
Table 2-42. RDRP Register Field Descriptions
Field
Description
7-0
RDRP
Port P reduced drive—Select reduced drive for output pin
This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
2.3.46
Port P Pull Device Enable Register (PERP)
Access: User read/write1
Address 0x025C
7
6
5
4
3
2
1
0
PPSP7
PPSP6
PPSP5
PPSP4
PPSP3
PPSP2
PPSP1
PPSP0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-44. Port P Pull Device Enable Register (PERP)
1
Read: Anytime.
Write: Anytime.
Table 2-43. PERP Register Field Descriptions
Field
Description
7-0
PERP
Port P pull device enable—Enable pull device on input pin
This bit controls whether a pull device on the associated port input pin is active. If a pin is used as output this bit has
no effect. The polarity is selected by the related polarity select register bit.
1 Pull device enabled
0 Pull device disabled
S12XS Family Reference Manual, Rev. 1.10
106
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.47
Port P Polarity Select Register (PPSP)
Access: User read/write1
Address 0x025D
7
6
5
4
3
2
1
0
PPSP7
PPSP6
PPSP5
PPSP4
PPSP3
PPSP2
PPSP1
PPSP0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-45. Port P Polarity Select Register (PPSP)
1
Read: Anytime.
Write: Anytime.
Table 2-44. PPSP Register Field Descriptions
Field
7-0
PPSP
Description
Port P pull device select—Configure pull device and pin interrupt edge polarity on input pin
This bit selects a pull-up or a pull-down device if enabled on the associated port input pin.
This bit also selects the polarity of the active pin interrupt edge.
1 A pull-down device selected; rising edge selected
0 A pull-up device selected; falling edge selected
2.3.48
Port P Interrupt Enable Register (PIEP)
Read: Anytime.
Access: User read/write1
Address 0x025E
7
6
5
4
3
2
1
0
PIEP7
PIEP6
PIEP5
PIEP4
PIEP3
PIEP2
PIEP1
PIEP0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-46. Port P Interrupt Enable Register (PIEP)
1
Read: Anytime.
Write: Anytime.
Table 2-45. PIEP Register Field Descriptions
Field
7-0
PIEP
Description
Port P interrupt enable—
This bit enables or disables on the edge sensitive pin interrupt on the associated pin.
1 Interrupt enabled
0 Interrupt disabled (interrupt flag masked)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
107
Port Integration Module (S12XSPIMV1)
2.3.49
Port P Interrupt Flag Register (PIFP)
Access: User read/write1
Address 0x025F
7
6
5
4
3
2
1
0
PIFP7
PIFP6
PIFP5
PIFP4
PIFP3
PIFP2
PIFP1
PIFP0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-47. Port P Interrupt Flag Register (PIFP)
1
Read: Anytime.
Write: Anytime.
Table 2-46. PIFP Register Field Descriptions
Field
Description
7-0
PIFP
Port P interrupt flag—
The flag bit is set after an active edge was applied to the associated input pin. This can be a rising or a falling edge
based on the state of the polarity select register.
Writing a logic “1” to the corresponding bit field clears the flag.
1 Active edge on the associated bit has occurred (an interrupt will occur if the associated enable bit is set)
0 No active edge occurred
2.3.50
Port H Data Register (PTH)
Access: User read/write1
Address 0x0260
7
6
5
4
3
2
1
0
PTH7
PTH6
PTH5
PTH4
PTH3
PTH2
PTH1
PTH0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-48. Port H Data Register (PTH)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-47. PTH Register Field Descriptions
Field
Description
7-0
PTH
Port H general purpose input/output data—Data Register, pin interrupt input/output
The associated pin can be used as general purpose I/O. In general purpose output mode the register bit value is
driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• Pin interrupts can be generated if enabled in input or output mode.
S12XS Family Reference Manual, Rev. 1.10
108
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.51
Port H Input Register (PTIH)
Access: User read1
Address 0x0261
R
7
6
5
4
3
2
1
0
PTIH7
PTIH6
PTIH5
PTIH4
PTIH3
PTIH2
PTIH1
PTIH0
u
u
u
u
u
u
u
u
W
Reset
= Unimplemented or Reserved
u = Unaffected by reset
Figure 2-49. Port H Input Register (PTIH)
1
Read: Anytime.
Write:Never, writes to this register have no effect.
Table 2-48. PTIH Register Field Descriptions
Field
Description
7-0
PTIH
Port H input data—
A read always returns the buffered input state of the associated pin. It can be used to detect overload or short circuit
conditions on output pins.
2.3.52
Port H Data Direction Register (DDRH)
Access: User read/write1
Address 0x0262
7
6
5
4
3
2
1
0
DDRH7
DDRH6
DDRH5
DDRH4
DDRH3
DDRH2
DDRH1
DDRH0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-50. Port H Data Direction Register (DDRH)
1
Read: Anytime.
Write: Anytime.
Table 2-49. DDRH Register Field Descriptions
Field
7-0
DDRH
Description
Port H data direction—
This bit determines whether the associated pin is an input or output.
1 Associated pin configured as output
0 Associated pin configured as input
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
109
Port Integration Module (S12XSPIMV1)
2.3.53
Port H Reduced Drive Register (RDRH)
Access: User read/write1
Address 0x0263
7
6
5
4
3
2
1
0
RDRH7
RDRH6
RDRH5
RDRH4
RDRH3
RDRH2
RDRH1
RDRH0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-51. Port H Reduced Drive Register (RDRH)
1
Read: Anytime.
Write: Anytime.
Table 2-50. RDRH Register Field Descriptions
Field
Description
7-0
RDRH
Port H reduced drive—Select reduced drive for output pin
This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
2.3.54
Port H Pull Device Enable Register (PERH)
Access: User read/write1
Address 0x0264
7
6
5
4
3
2
1
0
PERH7
PERH6
PERH5
PERH4
PERH3
PERH2
PERH1
PERH0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-52. Port H Pull Device Enable Register (PERH)
1
Read: Anytime.
Write: Anytime.
Table 2-51. PERH Register Field Descriptions
Field
Description
7-0
PERH
Port H pull device enable—Enable pull device on input pin
This bit controls whether a pull device on the associated port input pin is active. If a pin is used as output this bit has
no effect. The polarity is selected by the related polarity select register bit.
1 Pull device enabled
0 Pull device disabled
S12XS Family Reference Manual, Rev. 1.10
110
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.55
Port H Polarity Select Register (PPSH)
Access: User read/write1
Address 0x025D
7
6
5
4
3
2
1
0
PPSH7
PPSH6
PPSH5
PPSH4
PPSH3
PPSH2
PPSH1
PPSH0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-53. Port H Polarity Select Register (PPSH)
1
Read: Anytime.
Write: Anytime.
Table 2-52. PPSH Register Field Descriptions
Field
7-0
PPSH
Description
Port H pull device select—Configure pull device and pin interrupt edge polarity on input pin
This bit selects a pull-up or a pull-down device if enabled on the associated port input pin.
This bit also selects the polarity of the active pin interrupt edge.
1 A pull-down device selected; rising edge selected
0 A pull-up device selected; falling edge selected
2.3.56
Port H Interrupt Enable Register (PIEH)
Read: Anytime.
Access: User read/write1
Address 0x025E
7
6
5
4
3
2
1
0
PIEH7
PIEH6
PIEH5
PIEH4
PIEH3
PIEH2
PIEH1
PIEH0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-54. Port H Interrupt Enable Register (PIEH)
1
Read: Anytime.
Write: Anytime.
Table 2-53. PIEH Register Field Descriptions
Field
7-0
PIEH
Description
Port H interrupt enable—
This bit enables or disables on the edge sensitive pin interrupt on the associated pin.
1 Interrupt enabled
0 Interrupt disabled (interrupt flag masked)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
111
Port Integration Module (S12XSPIMV1)
2.3.57
Port H Interrupt Flag Register (PIFH)
Access: User read/write1
Address 0x025F
7
6
5
4
3
2
1
0
PIFH7
PIFH6
PIFH5
PIFH4
PIFH3
PIFH2
PIFH1
PIFH0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-55. Port H Interrupt Flag Register (PIFH)
1
Read: Anytime.
Write: Anytime.
Table 2-54. PIFH Register Field Descriptions
Field
Description
7-0
PIFH
Port H interrupt flag—
The flag bit is set after an active edge was applied to the associated input pin. This can be a rising or a falling edge
based on the state of the polarity select register.
Writing a logic “1” to the corresponding bit field clears the flag.
1 Active edge on the associated bit has occurred (an interrupt will occur if the associated enable bit is set)
0 No active edge occurred
2.3.58
Port J Data Register (PTJ)
Access: User read/write1
Address 0x0268
7
6
PTJ7
PTJ6
0
0
R
5
4
3
2
0
0
0
0
1
0
PTJ1
PTJ0
0
0
W
Reset
0
0
0
0
Figure 2-56. Port J Data Register (PTJ)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-55. PTJ Register Field Descriptions
Field
Description
7-6, 1-0
PTJ
Port J general purpose input/output data—Data Register, pin interrupt input/output
The associated pin can be used as general purpose I/O. In general purpose output mode the register bit value is
driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
• Pin interrupts can be generated if enabled in input or output mode.
S12XS Family Reference Manual, Rev. 1.10
112
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.59
Port J Input Register (PTIJ)
Access: User read1
Address 0x0269
R
7
6
5
4
3
2
1
0
PTIJ7
PTIJ6
0
0
0
0
PTIJ1
PTIJ0
u
u
u
u
u
u
u
u
W
Reset
= Unimplemented or Reserved
u = Unaffected by reset
Figure 2-57. Port J Input Register (PTIJ)
1
Read: Anytime.
Write:Never, writes to this register have no effect.
Table 2-56. PTIJ Register Field Descriptions
Field
Description
7-6, 1-0
PTIJ
Port J input data—
A read always returns the buffered input state of the associated pin. It can be used to detect overload or short circuit
conditions on output pins.
2.3.60
Port J Data Direction Register (DDRJ)
Access: User read/write1
Address 0x026A
7
6
DDRJ7
DDRJ6
0
0
R
5
4
3
2
0
0
0
0
1
0
DDRJ1
DDRJ0
0
0
W
Reset
0
0
0
0
Figure 2-58. Port J Data Direction Register (DDRJ)
1
Read: Anytime.
Write: Anytime.
Table 2-57. DDRJ Register Field Descriptions
Field
7-6, 1-0
DDRJ
Description
Port J data direction—
This bit determines whether the associated pin is an input or output.
1 Associated pin configured as output
0 Associated pin configured as input
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
113
Port Integration Module (S12XSPIMV1)
2.3.61
Port J Reduced Drive Register (RDRJ)
Access: User read/write1
Address 0x026B
7
6
RDRJ7
RDRJ6
0
0
R
5
4
3
2
0
0
0
0
1
0
RDRJ1
RDRJ0
0
0
W
Reset
0
0
0
0
Figure 2-59. Port J Reduced Drive Register (RDRJ)
1
Read: Anytime.
Write: Anytime.
Table 2-58. RDRJ Register Field Descriptions
Field
Description
7-6, 1-0
RDRJ
Port J reduced drive—Select reduced drive for outputs
This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength).
0 Full drive strength enabled.
2.3.62
Port J Pull Device Enable Register (PERJ)
Access: User read/write1
Address 0x026C
7
6
PERJ7
PERJ6
1
1
R
5
4
3
2
0
0
0
0
1
0
PERJ1
PERJ0
1
1
W
Reset
1
1
1
1
Figure 2-60. Port J Pull Device Enable Register (PERJ)
1
Read: Anytime.
Write: Anytime.
Table 2-59. PERJ Register Field Descriptions
Field
Description
7-6, 1-0
PERJ
Port J pull device enable—Enable pull device on input pin
This bit controls whether a pull device on the associated port input pin is active. If a pin is used as output this bit has
no effect. The polarity is selected by the related polarity select register bit.
1 Pull device enabled
0 Pull device disabled
S12XS Family Reference Manual, Rev. 1.10
114
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.63
Port J Polarity Select Register (PPSJ)
Access: User read/write1
Address 0x026D
7
6
PPSJ7
PPSJ6
0
0
R
5
4
3
2
0
0
0
0
1
0
PPSJ1
PPSJ0
0
0
W
Reset
0
0
0
0
Figure 2-61. Port J Polarity Select Register (PPSJ)
1
Read: Anytime.
Write: Anytime.
Table 2-60. PPSJ Register Field Descriptions
Field
7-6, 1-0
PPSJ
Description
Port J pull device select—Configure pull device and pin interrupt edge polarity on input pin
This bit selects a pull-up or a pull-down device if enabled on the associated port input pin.
This bit also selects the polarity of the active pin interrupt edge.
1 A pull-down device selected; rising edge selected
0 A pull-up device selected; falling edge selected
2.3.64
Port J Interrupt Enable Register (PIEJ)
Read: Anytime.
Access: User read/write1
Address 0x026E
7
6
PIEJ7
PIEJ6
0
0
R
5
4
3
2
0
0
0
0
1
0
PIEJ1
PIEJ0
0
0
W
Reset
0
0
0
0
Figure 2-62. Port J Interrupt Enable Register (PIEJ)
1
Read: Anytime.
Write: Anytime.
Table 2-61. PIEJ Register Field Descriptions
Field
7-6, 1-0
PIEJ
Description
Port J interrupt enable—
This bit enables or disables on the edge sensitive pin interrupt on the associated pin.
1 Interrupt enabled
0 Interrupt disabled (interrupt flag masked)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
115
Port Integration Module (S12XSPIMV1)
2.3.65
Port J Interrupt Flag Register (PIFJ)
Access: User read/write1
Address 0x026F
7
6
PIFJ7
PIFJ6
0
0
R
5
4
3
2
0
0
0
0
1
0
PIFJ1
PIFJ0
0
0
W
Reset
0
0
0
0
Figure 2-63. Port J Interrupt Flag Register (PIFJ)
1
Read: Anytime.
Write: Anytime.
Table 2-62. PIFJ Register Field Descriptions
Field
Description
7-6, 1-0
PIFJ
Port J interrupt flag—
The flag bit is set after an active edge was applied to the associated input pin. This can be a rising or a falling edge
based on the state of the polarity select register.
Writing a logic “1” to the corresponding bit field clears the flag.
1 Active edge on the associated bit has occurred (an interrupt will occur if the associated enable bit is set)
0 No active edge occurred
2.3.66
Port AD0 Data Register 0 (PT0AD0)
Access: User read/write1
Address 0x0270
7
6
5
4
3
2
1
0
PT0AD07
PT0AD06
PT0AD05
PT0AD04
PT0AD03
PT0AD02
PT0AD01
PT0AD00
AN15
AN14
AN13
AN12
AN11
AN10
AN9
AN8
0
0
0
0
0
0
0
0
R
W
Altern.
Function
Reset
Figure 2-64. Port AD0 Data Register 0 (PT0AD0)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-63. PT0AD0 Register Field Descriptions
Field
Description
7-0
PT0AD0
Port AD0 general purpose input/output data—Data Register, ATD AN analog input
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
S12XS Family Reference Manual, Rev. 1.10
116
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.67
Port AD0 Data Register 1 (PT1AD0)
Access: User read/write1
Address 0x0271
7
6
5
4
3
2
1
0
PT1AD07
PT1AD06
PT1AD05
PT1AD04
PT1AD03
PT1AD02
PT1AD01
PT1AD00
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
0
0
0
0
0
0
0
0
R
W
Altern.
Function
Reset
Figure 2-65. Port AD0 Data Register 1 (PT1AD0)
1
Read: Anytime. The data source depends on the data direction value.
Write: Anytime.
Table 2-64. PT1AD0 Register Field Descriptions
Field
Description
7-0
PT1AD0
Port AD0 general purpose input/output data—Data Register, ATD AN analog input
When not used with the alternative function, the associated pin can be used as general purpose I/O. In general
purpose output mode the register bit value is driven to the pin.
If the associated data direction bit is set to 1, a read returns the value of the port register bit, otherwise the buffered
pin input state is read.
2.3.68
Port AD0 Data Direction Register 0 (DDR0AD0)
Access: User read/write1
Address 0x0272
7
6
5
4
3
2
1
0
DDR0AD07
DDR0AD06
DDR0AD05
DDR0AD04
DDR0AD03
DDR0AD02
DDR0AD01
DDR0AD00
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-66. Port AD0 Data Direction Register 0 (DDR0AD0)
1
Read: Anytime.
Write: Anytime.
Table 2-65. DDR0AD0 Register Field Descriptions
Field
Description
7-0
Port AD0 data direction—
DDR0AD0 This bit determines whether the associated pin is an input or output.
To use the digital input function the ATD Digital Input Enable Register (ATD0DIEN) has to be set to logic level “1”.
1 Associated pin configured as output
0 Associated pin configured as input
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
117
Port Integration Module (S12XSPIMV1)
2.3.69
Port AD0 Data Direction Register 1 (DDR1AD0)
Access: User read/write1
Address 0x0273
7
6
5
4
3
2
1
0
DDR1AD07
DDR1AD06
DDR1AD05
DDR1AD04
DDR1AD03
DDR1AD02
DDR1AD01
DDR1AD00
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-67. Port AD0 Data Direction Register 1 (DDR1AD0)
1
Read: Anytime.
Write: Anytime.
Table 2-66. DDR1AD0 Register Field Descriptions
Field
Description
7-0
Port AD0 data direction—
DDR1AD0 This bit determines whether the associated pin is an input or output.
To use the digital input function the ATD Digital Input Enable Register (ATD0DIEN) has to be set to logic level “1”.
1 Associated pin configured as output
0 Associated pin configured as input
2.3.70
Port AD0 Reduced Drive Register 0 (RDR0AD0)
Access: User read/write1
Address 0x0274
7
6
5
4
3
2
1
0
RDR0AD07
RDR0AD06
RDR0AD05
RDR0AD04
RDR0AD03
RDR0AD02
RDR0AD01
RDR0AD00
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-68. Port AD0 Reduced Drive Register 0 (RDR0AD0)
1
Read: Anytime.
Write: Anytime.
Table 2-67. RDR0AD0 Register Field Descriptions
Field
Description
7-0
Port AD0 reduced drive—Select reduced drive for output pin
RDR0AD0 This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
S12XS Family Reference Manual, Rev. 1.10
118
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.3.71
Port AD0 Reduced Drive Register 1 (RDR1AD0)
Access: User read/write1
Address 0x0275
7
6
5
4
3
2
1
0
RDR1AD07
RDR1AD06
RDR1AD05
RDR1AD04
RDR1AD03
RDR1AD02
RDR1AD01
RDR1AD00
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-69. Port AD0 Reduced Drive Register 1 (RDR1AD0)
1
Read: Anytime.
Write: Anytime.
Table 2-68. RDR1AD0 Register Field Descriptions
Field
Description
7-0
Port AD0 reduced drive—Select reduced drive for output pin
RDR1AD0 This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/5 of the full drive strength)
0 Full drive strength enabled
2.3.72
Port AD0 Pull Up Enable Register 0 (PER0AD0)
Access: User read/write1
Address 0x0276
7
6
5
4
3
2
1
0
PER0AD07
PER0AD06
PER0AD05
PER0AD04
PER0AD03
PER0AD02
PER0AD01
PER0AD00
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-70. Port AD0 Pull Device Up Register 0 (PER0AD0)
1
Read: Anytime.
Write: Anytime.
Table 2-69. PER0AD0 Register Field Descriptions
Field
Description
7-0
Port AD0 pull device enable—Enable pull-up device on input pin
PER0AD0 This bit controls whether a pull device on the associated port input pin is active. If a pin is used as output this bit has
no effect. The polarity is selected by the related polarity select register bit.
1 Pull device enabled
0 Pull device disabled
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
119
Port Integration Module (S12XSPIMV1)
2.3.73
Port AD0 Pull Up Enable Register 1 (PER1AD0)
Access: User read/write1
Address 0x0277
7
6
5
4
3
2
1
0
PER1AD07
PER1AD06
PER1AD05
PER1AD04
PER1AD03
PER1AD02
PER1AD01
PER1AD00
0
0
0
0
0
0
0
0
R
W
Reset
Figure 2-71. Port AD0 Pull Up Enable Register 1 (PER1AD0)
1
Read: Anytime.
Write: Anytime.
Table 2-70. PER1AD0 Register Field Descriptions
Field
Description
7-0
Port AD0 pull device enable—Enable pull-up device on input pin
PER1AD0 This bit controls whether a pull device on the associated port input pin is active. If a pin is used as output this bit has
no effect. The polarity is selected by the related polarity select register bit.
1 Pull device enabled
0 Pull device disabled
2.3.74
PIM Reserved Registers
Access: User read1
Address 0x0278-0x27F
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
u = Unaffected by reset
Figure 2-72. PIM Reserved Registers
1
Read: Always reads 0x00
Write: Unimplemented
2.4
2.4.1
Functional Description
General
Each pin except PE0, PE1, and BKGD can act as general purpose I/O. In addition each pin can act as an
output or input of a peripheral module.
S12XS Family Reference Manual, Rev. 1.10
120
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.4.2
Registers
A set of configuration registers is common to all ports with exception of the ATD port (Table 2-71). All
registers can be written at any time, however a specific configuration might not become active.
For example selecting a pull-up device: This device does not become active while the port is used as a
push-pull output.
Table 2-71. Register availability per port1
1
Data
Reduced
Direction
Drive
Pull
Enable
Polarity
Select
WiredOr Mode
Interrupt
Enable
Interrupt
Flag
Routing
yes
-
-
-
-
-
yes
-
-
-
-
-
yes
-
-
-
-
-
-
-
-
-
-
yes
-
-
-
yes
Port
Data
Input
A
yes
-
yes
B
yes
-
E
yes
-
K
yes
-
yes
T
yes
yes
yes
yes
yes
yes
S
yes
yes
yes
yes
yes
yes
yes
-
-
-
M
yes
yes
yes
yes
yes
yes
yes
-
-
yes
P
yes
yes
yes
yes
yes
yes
-
yes
yes
-
H
yes
yes
yes
yes
yes
yes
-
yes
yes
-
J
yes
yes
yes
yes
yes
yes
-
yes
yes
-
AD
yes
-
yes
yes
yes
-
-
-
-
-
Each cell represents one register with individual configuration bits
2.4.2.1
Data register (PORTx, PTx)
This register holds the value driven out to the pin if the pin is used as a general purpose I/O.
Writing to this register has only an effect on the pin if the pin is used as general purpose output. When
reading this address, the buffered state of the pin is returned if the associated data direction register bit is
set to “0”.
If the data direction register bits are set to logic level “1”, the contents of the data register is returned. This
is independent of any other configuration (Figure 2-73).
2.4.2.2
Input register (PTIx)
This is a read-only register and always returns the buffered state of the pin (Figure 2-73).
2.4.2.3
Data direction register (DDRx)
This register defines whether the pin is used as a input or an output.
If a peripheral module controls the pin the contents of the data direction register is ignored (Figure 2-73).
Independent of the pin usage with a peripheral module this register determines the source of data when
reading the associated data register address (2.4.2.1/2-121).
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
121
Port Integration Module (S12XSPIMV1)
NOTE
Due to internal synchronization circuits, it can take up to 2 bus clock cycles
until the correct value is read on port data or port input registers, when
changing the data direction register.
PTI
0
1
PT
0
PIN
1
DDR
0
1
data out
Module
output enable
module enable
Figure 2-73. Illustration of I/O pin functionality
2.4.2.4
Reduced drive register (RDRx)
If the pin is used as an output this register allows the configuration of the drive strength independent of the
use with a peripheral module.
2.4.2.5
Pull device enable register (PERx)
This register turns on a pull-up or pull-down device on the related pins determined by the associated
polarity select register (2.4.2.5/2-122).
The pull device becomes active only if the pin is used as an input or as a wired-or output. Some peripheral
modules only allow certain configurations of pull devices to become active. Refer to the respective bit
descriptions.
2.4.2.6
Polarity select register (PPSx)
This register selects either a pull-up or pull-down device if enabled.
It only becomes active if the pin is used as an input. A pull-up device can be activated if the pin is used as
a wired-or output.
S12XS Family Reference Manual, Rev. 1.10
122
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
2.4.2.7
Wired-or mode register (WOMx)
If the pin is used as an output this register turns off the active high drive. This allows wired-or type
connections of outputs.
2.4.2.8
Interrupt enable register (PIEx)
If the pin is used as an interrupt input this register serves as a mask to the interrupt flag to enable/disable
the interrupt.
2.4.2.9
Interrupt flag register (PIFx)
If the pin is used as an interrupt input this register holds the interrupt flag after a valid pin event.
2.4.2.10
Module routing registers (MODRR, PTTRR)
These registers allow software re-configuration of the pinouts of the different package options for specific
peripherals:
• MODRR supports the re-routing of the SCI1 and SPI0 pins to alternative ports
• PTTRR supports the re-routing of the PWM and TIM channels to alternative ports
2.4.3
Pins and Ports
NOTE
Please refer to the device pinout section to determine the pin availability in
the different package options.
2.4.3.1
BKGD pin
The BKGD pin is associated with the BDM module.
During reset, the BKGD pin is used as MODC input.
2.4.3.2
Port A, B
Port A pins PA[7:0] and Port B pins PB[7:0] can be used for general-purpose I/O.
2.4.3.3
Port E
Port E is associated with the free-running clock outputs ECLK, ECLKX2 and interrupt inputs IRQ and
XIRQ.
Port E pins PE[7:2] can be used for either general-purpose I/O or with the alternative functions.
Port E pin PE[7] an be used for either general-purpose I/O or as the free-running clock ECLKX2 output
running at the core clock rate.
Port E pin PE[4] an be used for either general-purpose I/O or as the free-running clock ECLK output
running at the bus clock rate or at the programmed divided clock rate.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
123
Port Integration Module (S12XSPIMV1)
Port E pin PE[1] can be used for either general-purpose input or as the level- or falling edge-sensitive IRQ
interrupt input. IRQ will be enabled by setting the IRQEN configuration bit (2.3.14/2-83) and clearing the
I-bit in the CPU condition code register. It is inhibited at reset so this pin is initially configured as a simple
input with a pull-up.
Port E pin PE[0] can be used for either general-purpose input or as the level-sensitive XIRQ interrupt input.
XIRQ can be enabled by clearing the X-bit in the CPU condition code register. It is inhibited at reset so
this pin is initially configured as a high-impedance input with a pull-up.
2.4.3.4
Port K
Port K pins PK[7,5:0] can be used for general-purpose I/O.
2.4.3.5
Port T
This port is associated with TIM and PWM.
Port T pins PT[7:4] can be used for either general-purpose I/O, or with the PWM or with the channels of
the standard Timer subsystem.
Port T pins PT[3:0] can be used for either general-purpose I/O, or with the channels of the standard Timer
subsystem.
The TIM pins IOC2-0 can be re-routed.
2.4.3.6
Port S
This port is associated with SPI0, SCI0 and SCI1.
Port S pins PS[7:4] can be used either for general-purpose I/O, or with the SPI0 subsystem.
Port S pins PS[3:2] can be used either for general-purpose I/O, or with the SCI1 subsystem.
Port S pins PS[1:0] can be used either for general-purpose I/O, or with the SCI0 subsystem.
The SPI0 and SCI1 pins can be re-routed.
2.4.3.7
Port M
This port is associated with CAN0 and SCI1.
Port M pins PM[7:6] can be used for either general purpose I/O.
Port M pins PM[1:0] can be used for either general purpose I/O, or with the CAN0 or with the SCI1
subsystem.
Port M pins PM[5:2] can be used for general purpose I/O.
2.4.3.8
Port P
This port is associated with the PWM, TIM and SCI1.
S12XS Family Reference Manual, Rev. 1.10
124
Freescale Semiconductor
Port Integration Module (S12XSPIMV1)
Port P pins PP[7:3] can be used for either general purpose I/O with pin interrupt capability, or with the
PWM or with the channels of the standard Timer.subsystem.
Port P pins PP[2,0] can be used for either general purpose I/O, or with the PWM or with the TIM or with
the SCI1 subsystem.
Port P pin PP[1] can be used for either general purpose I/O, or with the PWM or with the TIM subsystem.
2.4.3.9
Port H
Port H pins PH[7:0] can be used for general purpose I/O with pin interrupt capability.
2.4.3.10
Port J
Port J pins PJ[7,6,1,0] can be used for general purpose I/O with pin-interrupt capability.
2.4.3.11
Port AD
This port is associated with the ATD.
Port AD pins PAD[15:0] can be used for either general purpose I/O, or with the ATD0 subsystem.
2.4.4
Pin interrupts
Ports P, H and J offer pin interrupt capability. The interrupt enable as well as the sensitivity to rising or
falling edges can be individually configured on a per-pin basis. All bits/pins in a port share the same
interrupt vector. Interrupts can be used with the pins configured as inputs or outputs.
An interrupt is generated when a bit in the port interrupt flag register and its corresponding port interrupt
enable bit are both set. The pin interrupt feature is also capable to wake up the CPU when it is in STOP or
WAIT mode.
A digital filter on each pin prevents pulses (Figure 2-75) shorter than a specified time from generating an
interrupt. The minimum time varies over process conditions, temperature and voltage (Figure 2-74 and
Table 2-72).
Glitch, filtered out, no interrupt flag set
Valid pulse, interrupt flag set
uncertain
tpign
tpval
Figure 2-74. Interrupt Glitch Filter on Port P, H and J (PPS=0)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
125
Port Integration Module (S12XSPIMV1)
Table 2-72. Pulse Detection Criteria
Mode
Pulse
STOP1
STOP
Unit
Ignored
Uncertain
Valid
tpulse ≤ 3
bus clocks
tpulse ≤ tpign
3 < tpulse < 4
bus clocks
tpign < tpulse < tpval
tpulse ≥ 4
bus clocks
tpulse ≥ tpval
1
These values include the spread of the oscillator frequency over temperature, voltage and process.
tpulse
Figure 2-75. Pulse Illustration
A valid edge on an input is detected if 4 consecutive samples of a passive level are followed by 4
consecutive samples of an active level directly or indirectly.
The filters are continuously clocked by the bus clock in RUN and WAIT mode. In STOP mode the clock
is generated by an RC-oscillator in the Port Integration Module. To maximize current saving the RC
oscillator runs only if the following condition is true on any pin individually:
Sample count <= 4 and interrupt enabled (PIE=1) and interrupt flag not set (PIF=0).
2.5
2.5.1
Initialization Information
Port Data and Data Direction Register writes
It is not recommended to write PORTx/PTx and DDRx in a word access. When changing the register pins
from inputs to outputs, the data may have extra transitions during the write access. Initialize the port data
register before enabling the outputs.
S12XS Family Reference Manual, Rev. 1.10
126
Freescale Semiconductor
Chapter 3
Memory Mapping Control (S12XMMCV4)
Revision History
Rev. No.
(Item No.)
Date (Submitted
By)
v04.08
04-May-07
- Clarifying RPAGE usage for less than 12KB RAMSIZE.
- Some Cleanups
v04.09
01-Feb-08
- Minor changes
v04.10
17-Feb-09
- Minor changes
3.1
Sections
Affected
Substantial Change(s)
Introduction
This section describes the functionality of the module mapping control (MMC) sub-block of the S12X
platform. The block diagram of the MMC is shown in Figure 3-1.
The MMC module controls the multi-master priority accesses, the selection of internal resources . Internal
buses, including internal memories and peripherals, are controlled in this module. The local address space
for each master is translated to a global memory space.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
127
Memory Mapping Control (S12XMMCV4)
3.1.1
Terminology
Table 3-1. Acronyms and Abbreviations
Logic level “1”
Logic level “0”
Voltage that corresponds to Boolean false state
0x
Represents hexadecimal number
x
Represents logic level ’don’t care’
Byte
8-bit data
word
16-bit data
local address
based on the 64KB Memory Space (16-bit address)
global address
based on the 8MB Memory Space (23-bit address)
Aligned address
Mis-aligned address
Bus Clock
single-chip modes
normal modes
special modes
Address on even boundary
Address on odd boundary
System Clock. Refer to CRG Block Guide.
Normal Single-Chip Mode
Special Single-Chip Mode
Normal Single-Chip Mode
Special Single-Chip Mode
NS
Normal Single-Chip Mode
SS
Special Single-Chip Mode
Unimplemented areas
Areas which are accessible by the pages (RPAGE,PPAGE,EPAGE) and not implemented
PRR
Port Replacement Registers
PRU
Port Replacement Unit located on the emulator side
MCU
MicroController Unit
NVM
Non-volatile Memory; Flash, Data FLASH or ROM
IFR
3.1.2
Voltage that corresponds to Boolean true state
Information Row sector located on the top of NVM. For Test purposes.
Features
The main features of this block are:
• Paging capability to support a global 8MB memory address space
• Bus arbitration between the masters CPU, BDM
• Simultaneous accesses to different resources1 (internal, and peripherals) (see Figure 3-1 )
• Resolution of target bus access collision
• MCU operation mode control
• MCU security control
• Separate memory map schemes for each master CPU, BDM
• ROM control bits to enable the on-chip FLASH or ROM selection
• Generation of system reset when CPU accesses an unimplemented address (i.e., an address which
does not belong to any of the on-chip modules) in single-chip modes
1.
Resources are also called targets.
S12XS Family Reference Manual, Rev. 1.10
128
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
3.1.3
S12X Memory Mapping
The S12X architecture implements a number of memory mapping schemes including
• a CPU 8MB global map, defined using a global page (GPAGE) register and dedicated 23-bit
address load/store instructions.
• a BDM 8MB global map, defined using a global page (BDMGPR) register and dedicated 23-bit
address load/store instructions.
• a (CPU or BDM) 64KB local map, defined using specific resource page (RPAGE, EPAGE and
PPAGE) registers and the default instruction set. The 64KB visible at any instant can be considered
as the local map accessed by the 16-bit (CPU or BDM) address.
The MMC module performs translation of the different memory mapping schemes to the specific global
(physical) memory implementation.
3.1.4
Modes of Operation
This subsection lists and briefly describes all operating modes supported by the MMC.
3.1.4.1
•
•
•
Run mode
MMC is functional during normal run mode.
Wait mode
MMC is functional during wait mode.
Stop mode
MMC is inactive during stop mode.
3.1.4.2
•
3.1.5
Power Saving Modes
Functional Modes
Single chip modes
In normal and special single chip mode the internal memory is used.
Block Diagram
Figure 3-1 shows a block diagram of the MMC.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
129
Memory Mapping Control (S12XMMCV4)
CPU
BDM
MMC
Address Decoder & Priority
DBG
Target Bus Controller
Data FLASH
PGMFLASH
RAM
Peripherals
Figure 3-1. MMC Block Diagram
3.2
External Signal Description
The user is advised to refer to the SoC Guide for port configuration and location of external bus signals.
Some pins may not be bonded out in all implementations.
Table 3-2 outlines the pin names and functions. It also provides a brief description of their operation.
Table 3-2. External Input Signals Associated with the MMC
Signal
I/O
Description
Availability
MODC
I
Mode input
Latched after
RESET (active low)
S12XS Family Reference Manual, Rev. 1.10
130
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
3.3
3.3.1
Memory Map and Registers
Module Memory Map
A summary of the registers associated with the MMC block is shown in Figure 3-2. Detailed descriptions
of the registers and bits are given in the subsections that follow.
Address
Register
Name
0x000A
Reserved
R
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
GP6
GP5
GP4
GP3
GP2
GP1
GP0
DP15
DP14
DP13
DP12
DP11
DP10
DP9
DP8
0
0
0
0
0
0
0
0
0
0
0
0
W
0x000B
MODE
R
W
0x0010
GPAGE
R
MODC
0
W
0x0011
DIRECT
R
W
0x0012
Reserved
R
W
0x0013
MMCCTL1
R
W
0x0014
Reserved
R
MGRAMON
0
DFIFRON PGMIFRON
0
0
0
0
0
0
0
0
PIX7
PIX6
PIX5
PIX4
PIX3
PIX2
PIX1
PIX0
RP7
RP6
RP5
RP4
RP3
RP2
RP1
RP0
EP7
EP6
EP5
EP4
EP3
EP2
EP1
EP0
W
0x0015
PPAGE
R
W
0x0016
RPAGE
R
W
0x0017
EPAGE
R
W
= Unimplemented or Reserved
Figure 3-2. MMC Register Summary
3.3.2
Register Descriptions
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
131
Memory Mapping Control (S12XMMCV4)
3.3.2.1
Mode Register (MODE)
Address: 0x000B PRR
7
R
W
Reset
MODC
MODC1
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1. External signal (see Table 3-2).
= Unimplemented or Reserved
Figure 3-3. Mode Register (MODE)
Read: Anytime. Write: Only if a transition is allowed (see Figure 3-5).
The MODE bits of the MODE register are used to establish the MCU operating mode.
Table 3-3. MODE Field Descriptions
Field
Description
7
MODC
Mode Select Bit — This bit controls the current operating mode during RESET high (inactive). The external
mode pin MODC determines the operating mode during RESET low (active). The state of the pin is latched into
the respective register bit after the RESET signal goes inactive (see Figure 3-3).
Write restrictions exist to disallow transitions between certain modes. Figure 3-5 illustrates all allowed mode
changes. Attempting non authorized transitions will not change the MODE bits, but it will block further writes to
these register bits except in special modes.
Write accesses to the MODE register are blocked when the device is secured.
Figure 3-4.
RESET
1
Normal
Single-Chip
(NS)
1
1
Special
Single-Chip
(SS)
0
RESET
0
Transition done by external pins (MODC)
RESET
State
Transition done by write access to the MODE register
State
State
Figure 3-5. Mode Transition Diagram when MCU is Unsecured
S12XS Family Reference Manual, Rev. 1.10
132
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
3.3.2.2
Global Page Index Register (GPAGE)
Address: 0x0010
7
R
0
W
Reset
0
6
5
4
3
2
1
0
GP6
GP5
GP4
GP3
GP2
GP1
GP0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 3-6. Global Page Index Register (GPAGE)
Read: Anytime
Write: Anytime
The global page index register is used to construct a 23 bit address in the global map format. It is only used
when the CPU is executing a global instruction (GLDAA, GLDAB, GLDD, GLDS, GLDX,
GLDY,GSTAA, GSTAB, GSTD, GSTS, GSTX, GSTY) (see CPU Block Guide). The generated global
address is the result of concatenation of the CPU local address [15:0] with the GPAGE register [22:16] (see
Figure 3-7).
Global Address [22:0]
Bit22
Bit16 Bit15
GPAGE Register [6:0]
Bit 0
CPU Address [15:0]
Figure 3-7. GPAGE Address Mapping
Table 3-4. GPAGE Field Descriptions
Field
Description
6–0
GP[6:0]
Global Page Index Bits 6–0 — These page index bits are used to select which of the 128 64KB pages is to be
accessed.
Example 3-1. This example demonstrates usage of the GPAGE register
LDX
MOVB
GLDAA
#0x5000
#0x14, GPAGE
X
;Set GPAGE offset to the value of 0x5000
;Initialize GPAGE register with the value of 0x14
;Load Accu A from the global address 0x14_5000
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
133
Memory Mapping Control (S12XMMCV4)
3.3.2.3
Direct Page Register (DIRECT)
Address: 0x0011
R
W
7
6
5
4
3
2
1
0
DP15
DP14
DP13
DP12
DP11
DP10
DP9
DP8
0
0
0
0
0
0
0
0
Reset
Figure 3-8. Direct Register (DIRECT)
Read: Anytime
Write: anytime in special modes, one time only in other modes.
This register determines the position of the 256B direct page within the memory map.It is valid for both
global and local mapping scheme.
Table 3-5. DIRECT Field Descriptions
Field
Description
7–0
DP[15:8]
Direct Page Index Bits 15–8 — These bits are used by the CPU when performing accesses using the direct
addressing mode. The bits from this register form bits [15:8] of the address (see Figure 3-9).
Global Address [22:0]
Bit22
Bit16 Bit15
Bit8
Bit7
Bit0
DP [15:8]
CPU Address [15:0]
Figure 3-9. DIRECT Address Mapping
Bits [22:16] of the global address will be formed by the GPAGE[6:0] bits in case the CPU executes a global
instruction in direct addressing mode or by the appropriate local address to the global address expansion
(refer to Section 3.4.2.1.1, “Expansion of the Local Address Map).
Example 3-2. This example demonstrates usage of the Direct Addressing Mode
MOVB
#0x80,DIRECT
;Set DIRECT register to 0x80. Write once only.
;Global data accesses to the range 0xXX_80XX can be direct.
;Logical data accesses to the range 0x80XX are direct.
LDY
<00
;Load the Y index register from 0x8000 (direct access).
;< operator forces direct access on some assemblers but in
;many cases assemblers are “direct page aware” and can
;automatically select direct mode.
S12XS Family Reference Manual, Rev. 1.10
134
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
3.3.2.4
MMC Control Register (MMCCTL1)
Address: 0x0013 PRR
7
R
W
6
MGRAMON
Reset
5
0
0
4
DFIFRON
PGMIFRON
0
0
0
3
2
1
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 3-10. MMC Control Register (MMCCTL1)
Read: Anytime. .
Write: Refer to each bit description.
Table 3-6. MMCCTL1 Field Descriptions
Field
Description
7
Flash Memory Controller SCRATCH RAM visible in the global memory map
MGRAMON Write: Anytime
This bit is used to made the Flash Memory Controller SCRATCH RAM visible in the global memory map.
0 Not visible in the global memory map.
1 Visible in the global memory map.
5
DFIFRON
Data Flash Information Row (IFR) visible in the global memory map
Write: Anytime
This bit is used to made the IFR sector of the Data Flash visible in the global memory map.
0 Not visible in the global memory map.
1 Visible in the global memory map.
4
Program Flash Information Row (IFR) visible in the global memory map
PGMIFRON Write: Anytime
This bit is used to map the IFR sector of the Program Flash to address range 0x40_000-0x40_3FFF of the global
memory map.
0 Not visible in the global memory map.
1 Visible in the global memory map.
3.3.2.5
Program Page Index Register (PPAGE)
Address: 0x0015
R
W
Reset
7
6
5
4
3
2
1
0
PIX7
PIX6
PIX5
PIX4
PIX3
PIX2
PIX1
PIX0
1
1
1
1
1
1
1
0
Figure 3-11. Program Page Index Register (PPAGE)
Read: Anytime
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
135
Memory Mapping Control (S12XMMCV4)
Write: Anytime
These eight index bits are used to page 16KB blocks into the Flash page window located in the local (CPU
or BDM) memory map from address 0x8000 to address 0xBFFF (see Figure 3-12). This supports
accessing up to 4MB of Flash (in the Global map) within the 64KB Local map. The PPAGE register is
effectively used to construct paged Flash addresses in the Local map format. The CPU has special access
to read and write this register directly during execution of CALL and RTC instructions..
Global Address [22:0]
1
Bit21
Bit0
Bit14 Bit13
PPAGE Register [7:0]
Address [13:0]
Address: CPU Local Address
or BDM Local Address
Figure 3-12. PPAGE Address Mapping
NOTE
Writes to this register using the special access of the CALL and RTC
instructions will be complete before the end of the instruction execution.
Table 3-7. PPAGE Field Descriptions
Field
7–0
PIX[7:0]
Description
Program Page Index Bits 7–0 — These page index bits are used to select which of the 256 FLASH or ROM
array pages is to be accessed in the Program Page Window.
The reset value of 0xFE ensures that there is linear Flash space available between addresses 0x4000 and
0xFFFF out of reset.
The fixed 16K page from 0xC000-0xFFFF is the page number 0xFF.
3.3.2.6
RAM Page Index Register (RPAGE)
Address: 0x0016
R
W
Reset
7
6
5
4
3
2
1
0
RP7
RP6
RP5
RP4
RP3
RP2
RP1
RP0
1
1
1
1
1
1
0
1
Figure 3-13. RAM Page Index Register (RPAGE)
S12XS Family Reference Manual, Rev. 1.10
136
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
Read: Anytime
Write: Anytime
These eight index bits are used to page 4KB blocks into the RAM page window located in the local (CPU
or BDM) memory map from address 0x1000 to address 0x1FFF (see Figure 3-14). This supports accessing
up to 1022KB of RAM (in the Global map) within the 64KB Local map. The RAM page index register is
effectively used to construct paged RAM addresses in the Local map format.
Global Address [22:0]
0
0
0
Bit19 Bit18
Bit12 Bit11
Bit0
Address [11:0]
RPAGE Register [7:0]
Address: CPU Local Address
or BDM Local Address
Figure 3-14. RPAGE Address Mapping
NOTE
Because RAM page 0 has the same global address as the register space, it is
possible to write to registers through the RAM space when RPAGE = 0x00.
Table 3-8. RPAGE Field Descriptions
Field
Description
7–0
RP[7:0]
RAM Page Index Bits 7–0 — These page index bits are used to select which of the 256 RAM array pages is to
be accessed in the RAM Page Window.
The reset value of 0xFD ensures that there is a linear RAM space available between addresses 0x1000 and
0x3FFF out of reset.
The fixed 4K page from 0x2000–0x2FFF of RAM is equivalent to page 254 (page number 0xFE).
The fixed 4K page from 0x3000–0x3FFF of RAM is equivalent to page 255 (page number 0xFF).
NOTE
The page 0xFD (reset value) contains unimplemented area in the range not
occupied by RAM if RAMSIZE is less than 12KB (Refer to Section 3.4.2.3,
“Implemented Memory Map).
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
137
Memory Mapping Control (S12XMMCV4)
The two fixed 4KB pages (0xFE, 0xFF) contain unimplemented area in the
range not occupied by RAM if RAMSIZE is less than 8KB (Refer to
Section 3.4.2.3, “Implemented Memory Map).
S12XS Family Reference Manual, Rev. 1.10
138
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
3.3.2.7
Data FLASH Page Index Register (EPAGE)
Address: 0x0017
R
W
7
6
5
4
3
2
1
0
EP7
EP6
EP5
EP4
EP3
EP2
EP1
EP0
1
1
1
1
1
1
1
0
Reset
Figure 3-15. Data FLASH Page Index Register (EPAGE)
Read: Anytime
Write: Anytime
These eight index bits are used to page 1KB blocks into the Data FLASH page window located in the local
(CPU or BDM) memory map from address 0x0800 to address 0x0BFF (see Figure 3-16). This supports
accessing up to 256KB of Data FLASH (in the Global map) within the 64KB Local map. The Data FLASH
page index register is effectively used to construct paged Data FLASH addresses in the Local map format.
Global Address [22:0]
0
0
1
0
0
Bit17 Bit16
Bit10 Bit9
Bit0
Address [9:0]
EPAGE Register [7:0]
Address: CPU Local Address
or BDM Local Address
Figure 3-16. EPAGE Address Mapping
Table 3-9. EPAGE Field Descriptions
Field
Description
7–0
EP[7:0]
Data FLASH Page Index Bits 7–0 — These page index bits are used to select which of the 256 Data FLASH
array pages is to be accessed in the Data FLASH Page Window.
The reset value of 0xFE ensures that there is a linear Data FLASH space available between addresses
0x0800 and 0x0FFF out of reset.
The fixed 1K page 0x0C00–0x0FFF of Data FLASH is equivalent to page 255 (page number 0xFF).
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
139
Memory Mapping Control (S12XMMCV4)
3.4
Functional Description
The MMC block performs several basic functions of the S12X sub-system operation: MCU operation
modes, priority control, address mapping, select signal generation and access limitations for the system.
Each aspect is described in the following subsections.
3.4.1
•
•
MCU Operating Mode
Normal single-chip mode
There is no external bus in this mode. The MCU program is executed from the internal memory
and no external accesses are allowed.
Special single-chip mode
This mode is generally used for debugging single-chip operation, boot-strapping or security related
operations. The active background debug mode is in control of the CPU code execution and the
BDM firmware is waiting for serial commands sent through the BKGD pin. There is no external
bus in this mode.
3.4.2
3.4.2.1
Memory Map Scheme
CPU and BDM Memory Map Scheme
The BDM firmware lookup tables and BDM register memory locations share addresses with other
modules; however they are not visible in the global memory map during user’s code execution. The BDM
memory resources are enabled only during the READ_BD and WRITE_BD access cycles to distinguish
between accesses to the BDM memory area and accesses to the other modules. (Refer to BDM Block
Guide for further details).
When the MCU enters active BDM mode, the BDM firmware lookup tables and the BDM registers
become visible in the local memory map in the range 0xFF00-0xFFFF (global address 0x7F_FF00 0x7F_FFFF) and the CPU begins execution of firmware commands or the BDM begins execution of
hardware commands. The resources which share memory space with the BDM module will not be visible
in the global memory map during active BDM mode.
Please note that after the MCU enters active BDM mode the BDM firmware lookup tables and the BDM
registers will also be visible between addresses 0xBF00 and 0xBFFF if the PPAGE register contains value
of 0xFF.
S12XS Family Reference Manual, Rev. 1.10
140
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
CPU and BDM
Local Memory Map
Global Memory Map
0x00_0000
2KB REGISTERS
0x00_0800
2KB RAM
RAM
253*4KB paged
0x0800
0x0C00
0x1000
0x0F_E000
2KB REGISTERS
1KB Data Flash window
8KB RAM
EPAGE
0x10_0000
Reserved
4KB RAM window
Data FLASH
256*1KB paged
RPAGE
0x2000
256KB
0x0000
1M minus 2KB
0x00_1000
8KB RAM
0x4000
0x13_FC00
Unimplemented
Space
0x8000
16KB FLASH window
2.75MB
0x14_0000
Unpaged
16KB FLASH
PPAGE
0x40_0000
0xC000
FLASH
253 *16KB paged
Unpaged
16KB FLASH
Reset Vectors
0x7F_4000
0x7F_8000
0x7F_C000
4MB
0xFFFF
16KB FLASH
(PPAGE 0xFD)
16KB FLASH
(PPAGE 0xFE)
16KB FLASH
(PPAGE 0xFF)
0x7F_FFFF
Figure 3-17. Expansion of the Local Address Map
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
141
Memory Mapping Control (S12XMMCV4)
3.4.2.1.1
Expansion of the Local Address Map
Expansion of the CPU Local Address Map
The program page index register in MMC allows accessing up to 4MB of FLASH or ROM in the global
memory map by using the eight page index bits to page 256 16KB blocks into the program page window
located from address 0x8000 to address 0xBFFF in the local CPU memory map.
The page value for the program page window is stored in the PPAGE register. The value of the PPAGE
register can be read or written by normal memory accesses as well as by the CALL and RTC instructions
(see Section 3.5.1, “CALL and RTC Instructions).
Control registers, vector space and parts of the on-chip memories are located in unpaged portions of the
64KB local CPU address space.
The starting address of an interrupt service routine must be located in unpaged memory unless the user is
certain that the PPAGE register will be set to the appropriate value when the service routine is called.
However an interrupt service routine can call other routines that are in paged memory. The upper 16KB
block of the local CPU memory space (0xC000–0xFFFF) is unpaged. It is recommended that all reset and
interrupt vectors point to locations in this area or to the other unpaged sections of the local CPU memory
map.
The RAM page index register allows accessing up to 1MB minus 2KB of RAM in the global memory map
by using the eight RPAGE index bits to page 4KB blocks into the RAM page window located in the local
CPU memory space from address 0x1000 to address 0x1FFF. The Data FLASH page index register
EPAGE allows accessing up to 256KB of Data Flash in the system by using the eight EPAGE index bits to
page 1KB blocks into the Data FLASH page window located in the local CPU memory space from address
0x0800 to address 0x0BFF.
S12XS Family Reference Manual, Rev. 1.10
142
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
Expansion of the BDM Local Address Map
PPAGE, RPAGE, and EPAGE registers are also used for the expansion of the BDM local address to the
global address. These registers can be read and written by the BDM.
The BDM expansion scheme is the same as the CPU expansion scheme.
3.4.2.2
Global Addresses Based on the Global Page
CPU Global Addresses Based on the Global Page
The seven global page index bits allow access to the full 8MB address map that can be accessed with 23
address bits. This provides an alternative way to access all of the various pages of FLASH, RAM and Data
FLASH.
The GPAGE Register is used only when the CPU is executing a global instruction (see Section 3.3.2.2,
“Global Page Index Register (GPAGE)). The generated global address is the result of concatenation of the
CPU local address [15:0] with the GPAGE register [22:16] (see Figure 3-7).
BDM Global Addresses Based on the Global Page
The seven BDMGPR Global Page index bits allow access to the full 8MB address map that can be accessed
with 23 address bits. This provides an alternative way to access all of the various pages of FLASH, RAM
and Data FLASH.
The BDM global page index register (BDMGPR) is used only in the case the CPU is executing a firmware
command which uses a global instruction (like GLDD, GSTD) or by a BDM hardware command (like
WRITE_W, WRITE_BYTE, READ_W, READ_BYTE). See the BDM Block Guide for further details.
The generated global address is a result of concatenation of the BDM local address with the BDMGPR
register [22:16] in the case of a hardware command or concatenation of the CPU local address and the
BDMGPR register [22:16] in the case of a firmware command (see Figure 3-18).
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
143
Memory Mapping Control (S12XMMCV4)
BDM HARDWARE COMMAND
Global Address [22:0]
Bit22
Bit16 Bit15
BDMGPR Register [6:0]
Bit0
BDM Local Address
BDM FIRMWARE COMMAND
Global Address [22:0]
Bit22
Bit16 Bit15
BDMGPR Register [6:0]
Bit0
CPU Local Address
Figure 3-18. BDMGPR Address Mapping
3.4.2.3
Implemented Memory Map
The global memory spaces reserved for the internal resources (RAM, Data FLASH, and FLASH) are not
determined by the MMC module. Size of the individual internal resources are however fixed in the design
of the device cannot be changed by the user. Please refer to the SoC Guide for further details. Figure 3-19
and Table 3-10 show the memory spaces occupied by the on-chip resources. Please note that the memory
spaces have fixed top addresses.
Table 3-10. Global Implemented Memory Space
Internal Resource
$Address
RAM
RAM_LOW = 0x10_0000 minus RAMSIZE1
Data FLASH
DF_HIGH = 0x10_0000 plus DFLASHSIZE2
FLASH
FLASH_LOW = 0x80_0000 minus FLASHSIZE3
1 RAMSIZE is the hexadecimal value of RAM SIZE in Bytes
2 DFLASHSIZE is the hexadecimal value of DFLASH SIZE in Bytes
3 FLASHSIZE is the hexadecimal value of FLASH SIZE in Bytes
S12XS Family Reference Manual, Rev. 1.10
144
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
In single-chip modes accesses by the CPU (except for firmware commands) to any of the unimplemented
areas (see Figure 3-19) will result in an illegal access reset (system reset) in case of no MPU error. BDM
accesses to the unimplemented areas are allowed but the data will be undefined.No misaligned word access
from the BDM module will occur; these accesses are blocked in the BDM module (Refer to BDM Block
Guide).
Misaligned word access to the last location of RAM is performed but the data will be undefined.
Misaligned word access to the last location of any global page (64KB) by any global instruction, is
performed by accessing the last byte of the page and the first byte of the same page, considering the above
mentioned misaligned access cases.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
145
Memory Mapping Control (S12XMMCV4)
CPU and BDM
Local Memory Map
Global Memory Map
0x00_0000
0x00_07FF
2K REGISTERS
Unimplemented
RAM
0x0000
0x0800
0x0C00
0x1000
RAM
2K REGISTERS
1K Data Flash window
EPAGE
0x0F_FFFF
Data FLASH
Reserved
DF_HIGH
4K RAM window
RPAGE
0x2000
Data FLASH
Resources
8K RAM
DFLASHSIZE RAMSIZE
RAM_LOW
0x4000
0x13_FFFF
Unpaged
16K FLASH
Unimplemented
Space
0x8000
16K FLASH window
PPAGE
0x3F_FFFF
0xC000
Unimplemented
FLASH
Unpaged
16K FLASH
Reset Vectors
FLASH_LOW
FLASH
FLASHSIZE
0xFFFF
0x7F_FFFF
Figure 3-19. S12X CPU & BDM Global Address Mapping
S12XS Family Reference Manual, Rev. 1.10
146
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
3.4.3
Chip Bus Control
The MMC controls the address buses and the data buses that interface the S12X masters (CPU, BDM )
with the rest of the system (master buses). In addition the MMC handles all CPU read data bus swapping
operations. All internal resources are connected to specific target buses (see Figure 3-20).
CPU
BDM
S12X1
S12X0
MMC
Address Decoder & Priority
DBG
Target Bus Controller
XBUS0
Data FLASH
PGMFLASH
RAM
Peripherals
Figure 3-20. MMC Block Diagram
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
147
Memory Mapping Control (S12XMMCV4)
3.4.3.1
Master Bus Prioritization regarding access conflicts on Target Buses
The arbitration scheme allows only one master to be connected to a target at any given time. The following
rules apply when prioritizing accesses from different masters to the same target bus:
• CPU always has priority over BDM .
• BDM has priority over CPU when its access is stalled for more than 128 cycles. In the later case
the suspect master will be stalled after finishing the current operation and the BDM will gain access
to the bus.
3.5
3.5.1
Initialization/Application Information
CALL and RTC Instructions
CALL and RTC instructions are uninterruptible CPU instructions that automate page switching in the
program page window. The CALL instruction is similar to the JSR instruction, but the subroutine that is
called can be located anywhere in the local address space or in any Flash or ROM page visible through the
program page window. The CALL instruction calculates and stacks a return address, stacks the current
PPAGE value and writes a new instruction-supplied value to the PPAGE register. The PPAGE value
controls which of the 256 possible pages is visible through the 16KB program page window in the 64KB
local CPU memory map. Execution then begins at the address of the called subroutine.
During the execution of the CALL instruction, the CPU performs the following steps:
1. Writes the current PPAGE value into an internal temporary register and writes the new instructionsupplied PPAGE value into the PPAGE register
2. Calculates the address of the next instruction after the CALL instruction (the return address) and
pushes this 16-bit value onto the stack
3. Pushes the temporarily stored PPAGE value onto the stack
4. Calculates the effective address of the subroutine, refills the queue and begins execution at the new
address
This sequence is uninterruptible. There is no need to inhibit interrupts during the CALL instruction
execution. A CALL instruction can be performed from any address to any other address in the local CPU
memory space.
The PPAGE value supplied by the instruction is part of the effective address of the CPU. For all addressing
mode variations (except indexed-indirect modes) the new page value is provided by an immediate operand
in the instruction. In indexed-indirect variations of the CALL instruction a pointer specifies memory
locations where the new page value and the address of the called subroutine are stored. Using indirect
addressing for both the new page value and the address within the page allows usage of values calculated
at run time rather than immediate values that must be known at the time of assembly.
The RTC instruction terminates subroutines invoked by a CALL instruction. The RTC instruction unstacks
the PPAGE value and the return address and refills the queue. Execution resumes with the next instruction
after the CALL instruction.
S12XS Family Reference Manual, Rev. 1.10
148
Freescale Semiconductor
Memory Mapping Control (S12XMMCV4)
During the execution of an RTC instruction the CPU performs the following steps:
1. Pulls the previously stored PPAGE value from the stack
2. Pulls the 16-bit return address from the stack and loads it into the PC
3. Writes the PPAGE value into the PPAGE register
4. Refills the queue and resumes execution at the return address
This sequence is uninterruptible. The RTC can be executed from anywhere in the local CPU memory
space.
The CALL and RTC instructions behave like JSR and RTS instruction, they however require more
execution cycles. Usage of JSR/RTS instructions is therefore recommended when possible and
CALL/RTC instructions should only be used when needed. The JSR and RTS instructions can be used to
access subroutines that are already present in the local CPU memory map (i.e. in the same page in the
program memory page window for example). However calling a function located in a different page
requires usage of the CALL instruction. The function must be terminated by the RTC instruction. Because
the RTC instruction restores contents of the PPAGE register from the stack, functions terminated with the
RTC instruction must be called using the CALL instruction even when the correct page is already present
in the memory map. This is to make sure that the correct PPAGE value will be present on stack at the time
of the RTC instruction execution.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
149
Memory Mapping Control (S12XMMCV4)
S12XS Family Reference Manual, Rev. 1.10
150
Freescale Semiconductor
Chapter 4
Interrupt (S12XINTV2)
Table 4-1. Revision History
Revision
Number
Revision Date
Sections
Affected
V02.00
01 Jul 2005
4.1.2/4-152
V02.04
11 Jan 2007
4.3.2.2/4-157
4.3.2.4/4-158
V02.05
20 Mar 2007
4.4.6/4-164
V02.06
07 Jan 2008
4.5.3.1/4-166
4.1
Description of Changes
Initial V2 release, added new features:
- XGATE threads can be interrupted.
- SYS instruction vector.
- Access violation interrupt vectors.
- Added Notes for devices without XGATE module.
- Fixed priority definition for software exceptions.
- Added clarification of “Wake-up from STOP or WAIT by XIRQ with X bit set”
feature.
Introduction
The XINT module decodes the priority of all system exception requests and provides the applicable vector
for processing the exception to either the CPU or the XGATE module. The XINT module supports:
• I bit and X bit maskable interrupt requests
• One non-maskable unimplemented op-code trap
• One non-maskable software interrupt (SWI) or background debug mode request
• One non-maskable system call interrupt (SYS)
• Three non-maskable access violation interrupt
• One spurious interrupt vector request
• Three system reset vector requests
Each of the I bit maskable interrupt requests can be assigned to one of seven priority levels supporting a
flexible priority scheme. For interrupt requests that are configured to be handled by the CPU, the priority
scheme can be used to implement nested interrupt capability where interrupts from a lower level are
automatically blocked if a higher level interrupt is being processed. Interrupt requests configured to be
handled by the XGATE module can be nested one level deep.
NOTE
The HPRIO register and functionality of the original S12 interrupt module
is no longer supported, since it is superseded by the 7-level interrupt request
priority scheme.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
151
Interrupt (S12XINTV2)
4.1.1
Glossary
The following terms and abbreviations are used in the document.
Table 4-2. Terminology
Term
CCR
Condition Code Register (in the S12X CPU)
DMA
Direct Memory Access
INT
Interrupt
IPL
Interrupt Processing Level
ISR
Interrupt Service Routine
MCU
XGATE
IRQ
XIRQ
4.1.2
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Meaning
Micro-Controller Unit
refers to the XGATE co-processor; XGATE is an optional feature
refers to the interrupt request associated with the IRQ pin
refers to the interrupt request associated with the XIRQ pin
Features
Interrupt vector base register (IVBR)
One spurious interrupt vector (at address vector base1 + 0x0010).
One non-maskable system call interrupt vector request (at address vector base + 0x0012).
Three non-maskable access violation interrupt vector requests (at address vector base + 0x0014−
0x0018).
2–109 I bit maskable interrupt vector requests (at addresses vector base + 0x001A–0x00F2).
Each I bit maskable interrupt request has a configurable priority level and can be configured to be
handled by either the CPU or the XGATE module2.
I bit maskable interrupts can be nested, depending on their priority levels.
One X bit maskable interrupt vector request (at address vector base + 0x00F4).
One non-maskable software interrupt request (SWI) or background debug mode vector request (at
address vector base + 0x00F6).
One non-maskable unimplemented op-code trap (TRAP) vector (at address vector base + 0x00F8).
Three system reset vectors (at addresses 0xFFFA–0xFFFE).
Determines the highest priority XGATE and interrupt vector requests, drives the vector to the
XGATE module or to the bus on CPU request, respectively.
Wakes up the system from stop or wait mode when an appropriate interrupt request occurs or
whenever XIRQ is asserted, even if X interrupt is masked.
XGATE can wake up and execute code, even with the CPU remaining in stop or wait mode.
The vector base is a 16-bit address which is accumulated from the contents of the interrupt vector base register (IVBR, used
as upper byte) and 0x00 (used as lower byte).
2. The IRQ interrupt can only be handled by the CPU
1.
S12XS Family Reference Manual, Rev. 1.10
152
Freescale Semiconductor
Interrupt (S12XINTV2)
4.1.3
•
•
•
•
Modes of Operation
Run mode
This is the basic mode of operation.
Wait mode
In wait mode, the XINT module is frozen. It is however capable of either waking up the CPU if an
interrupt occurs or waking up the XGATE if an XGATE request occurs. Please refer to
Section 4.5.3, “Wake Up from Stop or Wait Mode” for details.
Stop Mode
In stop mode, the XINT module is frozen. It is however capable of either waking up the CPU if an
interrupt occurs or waking up the XGATE if an XGATE request occurs. Please refer to
Section 4.5.3, “Wake Up from Stop or Wait Mode” for details.
Freeze mode (BDM active)
In freeze mode (BDM active), the interrupt vector base register is overridden internally. Please
refer to Section 4.3.2.1, “Interrupt Vector Base Register (IVBR)” for details.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
153
Interrupt (S12XINTV2)
4.1.4
Block Diagram
Figure 4-1 shows a block diagram of the XINT module.
Peripheral
Interrupt Requests
Wake Up
CPU
Non I Bit Maskable
Channels
Interrupt
Requests
Priority
Decoder
IRQ Channel
PRIOLVL2
PRIOLVL1
PRIOLVL0
RQST
IVBR
New
IPL
To CPU
Vector
Address
Current
IPL
One Set Per Channel
(Up to 108 Channels)
INT_XGPRIO
XGATE
Requests
Priority
Decoder
Wake up
XGATE
Vector
ID
XGATE
Interrupts
To XGATE Module
RQST
XGATE Request Route,
PRIOLVLn
Priority Level
= bits from the channel configuration
in the associated configuration register
INT_XGPRIO = XGATE Interrupt Priority
IVBR
= Interrupt Vector Base
IPL
= Interrupt Processing Level
Figure 4-1. XINT Block Diagram
4.2
External Signal Description
The XINT module has no external signals.
S12XS Family Reference Manual, Rev. 1.10
154
Freescale Semiconductor
Interrupt (S12XINTV2)
4.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the XINT module.
4.3.1
Module Memory Map
Table 4-3 gives an overview over all XINT module registers.
Table 4-3. XINT Memory Map
Address
Use
Access
0x0120
RESERVED
—
0x0121
Interrupt Vector Base Register (IVBR)
R/W
0x0122–0x0125
RESERVED
—
0x0126
XGATE Interrupt Priority Configuration Register
(INT_XGPRIO)
R/W
0x0127
Interrupt Request Configuration Address Register
(INT_CFADDR)
R/W
0x0128
Interrupt Request Configuration Data Register 0
(INT_CFDATA0)
R/W
0x0129
Interrupt Request Configuration Data Register 1
(INT_CFDATA1)
R/W
0x012A
Interrupt Request Configuration Data Register 2
(INT_CFDATA2
R/W
0x012B
Interrupt Request Configuration Data Register 3
(INT_CFDATA3)
R/W
0x012C
Interrupt Request Configuration Data Register 4
(INT_CFDATA4)
R/W
0x012D
Interrupt Request Configuration Data Register 5
(INT_CFDATA5)
R/W
0x012E
Interrupt Request Configuration Data Register 6
(INT_CFDATA6)
R/W
0x012F
Interrupt Request Configuration Data Register 7
(INT_CFDATA7)
R/W
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
155
Interrupt (S12XINTV2)
4.3.2
Register Descriptions
This section describes in address order all the XINT module registers and their individual bits.
Address
Register
Name
0x0121
IVBR
Bit 7
6
5
R
INT_XGPRIO
R
3
2
0
0
0
0
0
INT_CFADDR
R
R
W
0x0129 INT_CFDATA1
R
W
0x012A INT_CFDATA2
R
W
0x012B INT_CFDATA3
R
W
0x012C INT_CFDATA4
R
W
0x012D INT_CFDATA5
R
W
0x012E INT_CFDATA6
R
W
0x012F INT_CFDATA7
R
W
0
INT_CFADDR[7:4]
W
0x0128 INT_CFDATA0
Bit 0
XILVL[2:0]
W
0x0127
1
IVB_ADDR[7:0]7
W
0x0126
4
RQST
RQST
RQST
RQST
RQST
RQST
RQST
RQST
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
PRIOLVL[2:0]
PRIOLVL[2:0]
PRIOLVL[2:0]
PRIOLVL[2:0]
PRIOLVL[2:0]
PRIOLVL[2:0]
PRIOLVL[2:0]
PRIOLVL[2:0]
= Unimplemented or Reserved
Figure 4-2. XINT Register Summary
S12XS Family Reference Manual, Rev. 1.10
156
Freescale Semiconductor
Interrupt (S12XINTV2)
4.3.2.1
Interrupt Vector Base Register (IVBR)
Address: 0x0121
7
6
5
R
3
2
1
0
1
1
1
IVB_ADDR[7:0]
W
Reset
4
1
1
1
1
1
Figure 4-3. Interrupt Vector Base Register (IVBR)
Read: Anytime
Write: Anytime
Table 4-4. IVBR Field Descriptions
Field
Description
7–0
Interrupt Vector Base Address Bits — These bits represent the upper byte of all vector addresses. Out of
IVB_ADDR[7:0] reset these bits are set to 0xFF (i.e., vectors are located at 0xFF10–0xFFFE) to ensure compatibility to
previous S12 microcontrollers.
Note: A system reset will initialize the interrupt vector base register with “0xFF” before it is used to determine
the reset vector address. Therefore, changing the IVBR has no effect on the location of the three reset
vectors (0xFFFA–0xFFFE).
Note: If the BDM is active (i.e., the CPU is in the process of executing BDM firmware code), the contents of
IVBR are ignored and the upper byte of the vector address is fixed as “0xFF”.
4.3.2.2
XGATE Interrupt Priority Configuration Register (INT_XGPRIO)
Address: 0x0126
R
7
6
5
4
3
0
0
0
0
0
0
0
0
0
0
2
0
XILVL[2:0]
W
Reset
1
0
0
1
= Unimplemented or Reserved
Figure 4-4. XGATE Interrupt Priority Configuration Register (INT_XGPRIO)
Read: Anytime
Write: Anytime
Table 4-5. INT_XGPRIO Field Descriptions
Field
Description
2–0
XILVL[2:0]
XGATE Interrupt Priority Level — The XILVL[2:0] bits configure the shared interrupt level of the XGATE
interrupts coming from the XGATE module. Out of reset the priority is set to the lowest active level (“1”).
Note: If the XGATE module is not available on the device, write accesses to this register are ignored and read
accesses to this register will return all 0.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
157
Interrupt (S12XINTV2)
Table 4-6. XGATE Interrupt Priority Levels
Priority
low
high
4.3.2.3
XILVL2
XILVL1
XILVL0
Meaning
0
0
0
Interrupt request is disabled
0
0
1
Priority level 1
0
1
0
Priority level 2
0
1
1
Priority level 3
1
0
0
Priority level 4
1
0
1
Priority level 5
1
1
0
Priority level 6
1
1
1
Priority level 7
Interrupt Request Configuration Address Register (INT_CFADDR)
Address: 0x0127
7
R
5
4
INT_CFADDR[7:4]
W
Reset
6
0
0
0
1
3
2
1
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 4-5. Interrupt Configuration Address Register (INT_CFADDR)
Read: Anytime
Write: Anytime
Table 4-7. INT_CFADDR Field Descriptions
Field
Description
7–4
Interrupt Request Configuration Data Register Select Bits — These bits determine which of the 128
INT_CFADDR[7:4] configuration data registers are accessible in the 8 register window at INT_CFDATA0–7. The hexadecimal
value written to this register corresponds to the upper nibble of the lower byte of the address of the interrupt
vector, i.e., writing 0xE0 to this register selects the configuration data register block for the 8 interrupt vector
requests starting with vector at address (vector base + 0x00E0) to be accessible as INT_CFDATA0–7.
Note: Writing all 0s selects non-existing configuration registers. In this case write accesses to
INT_CFDATA0–7 will be ignored and read accesses will return all 0.
4.3.2.4
Interrupt Request Configuration Data Registers (INT_CFDATA0–7)
The eight register window visible at addresses INT_CFDATA0–7 contains the configuration data for the
block of eight interrupt requests (out of 128) selected by the interrupt configuration address register
(INT_CFADDR) in ascending order. INT_CFDATA0 represents the interrupt configuration data register
of the vector with the lowest address in this block, while INT_CFDATA7 represents the interrupt
configuration data register of the vector with the highest address, respectively.
S12XS Family Reference Manual, Rev. 1.10
158
Freescale Semiconductor
Interrupt (S12XINTV2)
Address: 0x0128
7
R
W
Reset
RQST
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
PRIOLVL[2:0]
0
0
11
= Unimplemented or Reserved
Figure 4-6. Interrupt Request Configuration Data Register 0 (INT_CFDATA0)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
Address: 0x0129
7
R
W
Reset
RQST
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
PRIOLVL[2:0]
0
0
11
= Unimplemented or Reserved
Figure 4-7. Interrupt Request Configuration Data Register 1 (INT_CFDATA1)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
Address: 0x012A
7
R
W
Reset
RQST
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
PRIOLVL[2:0]
0
0
11
= Unimplemented or Reserved
Figure 4-8. Interrupt Request Configuration Data Register 2 (INT_CFDATA2)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
Address: 0x012B
7
R
W
Reset
RQST
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
PRIOLVL[2:0]
0
0
11
= Unimplemented or Reserved
Figure 4-9. Interrupt Request Configuration Data Register 3 (INT_CFDATA3)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
159
Interrupt (S12XINTV2)
Address: 0x012C
7
R
W
Reset
RQST
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
PRIOLVL[2:0]
0
0
11
= Unimplemented or Reserved
Figure 4-10. Interrupt Request Configuration Data Register 4 (INT_CFDATA4)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
Address: 0x012D
7
R
W
Reset
RQST
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
PRIOLVL[2:0]
0
0
11
= Unimplemented or Reserved
Figure 4-11. Interrupt Request Configuration Data Register 5 (INT_CFDATA5)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
Address: 0x012E
7
R
W
Reset
RQST
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
PRIOLVL[2:0]
0
0
11
= Unimplemented or Reserved
Figure 4-12. Interrupt Request Configuration Data Register 6 (INT_CFDATA6)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
Address: 0x012F
7
R
W
Reset
RQST
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
PRIOLVL[2:0]
0
0
11
= Unimplemented or Reserved
Figure 4-13. Interrupt Request Configuration Data Register 7 (INT_CFDATA7)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
Read: Anytime
Write: Anytime
S12XS Family Reference Manual, Rev. 1.10
160
Freescale Semiconductor
Interrupt (S12XINTV2)
Table 4-8. INT_CFDATA0–7 Field Descriptions
Field
Description
7
RQST
XGATE Request Enable — This bit determines if the associated interrupt request is handled by the CPU or by
the XGATE module.
0 Interrupt request is handled by the CPU
1 Interrupt request is handled by the XGATE module
Note: The IRQ interrupt cannot be handled by the XGATE module. For this reason, the configuration register
for vector (vector base + 0x00F2) = IRQ vector address) does not contain a RQST bit. Writing a 1 to the
location of the RQST bit in this register will be ignored and a read access will return 0.
Note: If the XGATE module is not available on the device, writing a 1 to the location of the RQST bit in this
register will be ignored and a read access will return 0.
2–0
Interrupt Request Priority Level Bits — The PRIOLVL[2:0] bits configure the interrupt request priority level of
PRIOLVL[2:0] the associated interrupt request. Out of reset all interrupt requests are enabled at the lowest active level (“1”)
to provide backwards compatibility with previous S12 interrupt controllers. Please also refer to Table 4-9 for
available interrupt request priority levels.
Note: Write accesses to configuration data registers of unused interrupt channels will be ignored and read
accesses will return all 0. For information about what interrupt channels are used in a specific MCU,
please refer to the Device Reference Manual of that MCU.
Note: When vectors (vector base + 0x00F0–0x00FE) are selected by writing 0xF0 to INT_CFADDR, writes to
INT_CFDATA2–7 (0x00F4–0x00FE) will be ignored and read accesses will return all 0s. The
corresponding vectors do not have configuration data registers associated with them.
Note: When vectors (vector base + 0x0010–0x001E) are selected by writing 0x10 to INT_CFADDR, writes to
INT_CFDATA1–INT_CFDATA4 (0x0012–0x0018) will be ignored and read accesses will return all 0s. The
corresponding vectors do not have configuration data registers associated with them.
Note: Write accesses to the configuration register for the spurious interrupt vector request
(vector base + 0x0010) will be ignored and read accesses will return 0x07 (request is handled by the
CPU, PRIOLVL = 7).
Table 4-9. Interrupt Priority Levels
Priority
low
high
4.4
PRIOLVL2
PRIOLVL1
PRIOLVL0
Meaning
0
0
0
Interrupt request is disabled
0
0
1
Priority level 1
0
1
0
Priority level 2
0
1
1
Priority level 3
1
0
0
Priority level 4
1
0
1
Priority level 5
1
1
0
Priority level 6
1
1
1
Priority level 7
Functional Description
The XINT module processes all exception requests to be serviced by the CPU module. These exceptions
include interrupt vector requests and reset vector requests. Each of these exception types and their overall
priority level is discussed in the subsections below.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
161
Interrupt (S12XINTV2)
4.4.1
S12X Exception Requests
The CPU handles both reset requests and interrupt requests. The XINT module contains registers to
configure the priority level of each I bit maskable interrupt request which can be used to implement an
interrupt priority scheme. This also includes the possibility to nest interrupt requests. A priority decoder
is used to evaluate the priority of a pending interrupt request.
4.4.2
Interrupt Prioritization
After system reset all interrupt requests with a vector address lower than or equal to (vector base + 0x00F2)
are enabled, are set up to be handled by the CPU and have a pre-configured priority level of 1. Exceptions
to this rule are the non-maskable interrupt requests and the spurious interrupt vector request at (vector base
+ 0x0010) which cannot be disabled, are always handled by the CPU and have a fixed priority levels. A
priority level of 0 effectively disables the associated I bit maskable interrupt request.
If more than one interrupt request is configured to the same interrupt priority level the interrupt request
with the higher vector address wins the prioritization.
The following conditions must be met for an I bit maskable interrupt request to be processed.
1. The local interrupt enabled bit in the peripheral module must be set.
2. The setup in the configuration register associated with the interrupt request channel must meet the
following conditions:
a) The XGATE request enable bit must be 0 to have the CPU handle the interrupt request.
b) The priority level must be set to non zero.
c) The priority level must be greater than the current interrupt processing level in the condition
code register (CCR) of the CPU (PRIOLVL[2:0] > IPL[2:0]).
3. The I bit in the condition code register (CCR) of the CPU must be cleared.
4. There is no access violation interrupt request pending.
5. There is no SYS, SWI, BDM, TRAP, or XIRQ request pending.
NOTE
All non I bit maskable interrupt requests always have higher priority than
I bit maskable interrupt requests. If an I bit maskable interrupt request is
interrupted by a non I bit maskable interrupt request, the currently active
interrupt processing level (IPL) remains unaffected. It is possible to nest
non I bit maskable interrupt requests, e.g., by nesting SWI or TRAP calls.
4.4.2.1
Interrupt Priority Stack
The current interrupt processing level (IPL) is stored in the condition code register (CCR) of the CPU. This
way the current IPL is automatically pushed to the stack by the standard interrupt stacking procedure. The
new IPL is copied to the CCR from the priority level of the highest priority active interrupt request channel
which is configured to be handled by the CPU. The copying takes place when the interrupt vector is
fetched. The previous IPL is automatically restored by executing the RTI instruction.
S12XS Family Reference Manual, Rev. 1.10
162
Freescale Semiconductor
Interrupt (S12XINTV2)
4.4.3
XGATE Requests
If the XGATE module is implemented on the device, the XINT module is also used to process all exception
requests to be serviced by the XGATE module. The overall priority level of those exceptions is discussed
in the subsections below.
4.4.3.1
XGATE Request Prioritization
An interrupt request channel is configured to be handled by the XGATE module, if the RQST bit of the
associated configuration register is set to 1 (please refer to Section 4.3.2.4, “Interrupt Request
Configuration Data Registers (INT_CFDATA0–7)”). The priority level configuration (PRIOLVL) for this
channel becomes the XGATE priority which will be used to determine the highest priority XGATE request
to be serviced next by the XGATE module. Additionally, XGATE interrupts may be raised by the XGATE
module by setting one or more of the XGATE channel interrupt flags (by using the SIF instruction). This
will result in an CPU interrupt with vector address vector base + (2 * channel ID number), where the
channel ID number corresponds to the highest set channel interrupt flag, if the XGIE and channel RQST
bits are set.
The shared interrupt priority for the XGATE interrupt requests is taken from the XGATE interrupt priority
configuration register (please refer to Section 4.3.2.2, “XGATE Interrupt Priority Configuration Register
(INT_XGPRIO)”). If more than one XGATE interrupt request channel becomes active at the same time,
the channel with the highest vector address wins the prioritization.
4.4.4
Priority Decoders
The XINT module contains priority decoders to determine the priority for all interrupt requests pending
for the respective target.
There are two priority decoders, one for each interrupt request target, CPU or XGATE. The function of
both priority decoders is basically the same with one exception: the priority decoder for the XGATE
module does not take the current XGATE thread processing level into account. Instead, XGATE requests
are handed to the XGATE module including a 1-bit priority identifier. The XGATE module uses this
additional information to decide if the new request can interrupt a currently running thread. The 1-bit
priority identifier corresponds to the most significant bit of the priority level configuration of the requesting
channel. This means that XGATE requests with priority levels 4, 5, 6 or 7 can interrupt running XGATE
threads with priority levels 1, 2 and 3.
A CPU interrupt vector is not supplied until the CPU requests it. Therefore, it is possible that a higher
priority interrupt request could override the original exception which caused the CPU to request the vector.
In this case, the CPU will receive the highest priority vector and the system will process this exception
instead of the original request.
If the interrupt source is unknown (for example, in the case where an interrupt request becomes inactive
after the interrupt has been recognized, but prior to the vector request), the vector address supplied to the
CPU will default to that of the spurious interrupt vector.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
163
Interrupt (S12XINTV2)
NOTE
Care must be taken to ensure that all exception requests remain active until
the system begins execution of the applicable service routine; otherwise, the
exception request may not get processed at all or the result may be a
spurious interrupt request (vector at address (vector base + 0x0010)).
4.4.5
Reset Exception Requests
The XINT module supports three system reset exception request types (for details please refer to the Clock
and Reset Generator module (CRG)):
1. Pin reset, power-on reset, low-voltage reset, or illegal address reset
2. Clock monitor reset request
3. COP watchdog reset request
4.4.6
Exception Priority
The priority (from highest to lowest) and address of all exception vectors issued by the XINT module upon
request by the CPU is shown in Table 4-10. Generally, all non-maskable interrupts have higher priorities
than maskable interrupts. Please note that between the three software interrupts (Unimplemented op-code
trap request, SWI/BGND request, SYS request) there is no real priority defined because they cannot occur
simultaneously (the S12XCPU executes one instruction at a time).
Table 4-10. Exception Vector Map and Priority
Vector Address1
Source
0xFFFE
Pin reset, power-on reset, low-voltage reset, illegal address reset
0xFFFC
Clock monitor reset
0xFFFA
COP watchdog reset
(Vector base + 0x00F8)
Unimplemented op-code trap
(Vector base + 0x00F6)
Software interrupt instruction (SWI) or BDM vector request
(Vector base + 0x0012)
System call interrupt instruction (SYS)
(Vector base + 0x0018)
(reserved for future use)
(Vector base + 0x0016)
XGATE Access violation interrupt request2
(Vector base + 0x0014)
CPU Access violation interrupt request3
(Vector base + 0x00F4)
XIRQ interrupt request
(Vector base + 0x00F2)
IRQ interrupt request
(Vector base +
0x00F0–0x001A)
Device specific I bit maskable interrupt sources (priority determined by the associated
configuration registers, in descending order)
(Vector base + 0x0010)
Spurious interrupt
16 bits vector address based
2 only implemented if device features both a Memory Protection Unit (MPU) and an XGATE co-processor
3 only implemented if device features a Memory Protection Unit (MPU)
1
S12XS Family Reference Manual, Rev. 1.10
164
Freescale Semiconductor
Interrupt (S12XINTV2)
4.5
4.5.1
Initialization/Application Information
Initialization
After system reset, software should:
• Initialize the interrupt vector base register if the interrupt vector table is not located at the default
location (0xFF10–0xFFF9).
• Initialize the interrupt processing level configuration data registers (INT_CFADDR,
INT_CFDATA0–7) for all interrupt vector requests with the desired priority levels and the request
target (CPU or XGATE module). It might be a good idea to disable unused interrupt requests.
• If the XGATE module is used, setup the XGATE interrupt priority register (INT_XGPRIO) and
configure the XGATE module (please refer the XGATE Block Guide for details).
• Enable I maskable interrupts by clearing the I bit in the CCR.
• Enable the X maskable interrupt by clearing the X bit in the CCR (if required).
4.5.2
Interrupt Nesting
The interrupt request priority level scheme makes it possible to implement priority based interrupt request
nesting for the I bit maskable interrupt requests handled by the CPU.
• I bit maskable interrupt requests can be interrupted by an interrupt request with a higher priority,
so that there can be up to seven nested I bit maskable interrupt requests at a time (refer to Figure 414 for an example using up to three nested interrupt requests).
I bit maskable interrupt requests cannot be interrupted by other I bit maskable interrupt requests per
default. In order to make an interrupt service routine (ISR) interruptible, the ISR must explicitly clear the
I bit in the CCR (CLI). After clearing the I bit, I bit maskable interrupt requests with higher priority can
interrupt the current ISR.
An ISR of an interruptible I bit maskable interrupt request could basically look like this:
• Service interrupt, e.g., clear interrupt flags, copy data, etc.
• Clear I bit in the CCR by executing the instruction CLI (thus allowing interrupt requests with
higher priority)
• Process data
• Return from interrupt by executing the instruction RTI
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
165
Interrupt (S12XINTV2)
0
Stacked IPL
IPL in CCR
0
0
4
0
0
0
4
7
4
3
1
0
7
6
RTI
L7
5
4
RTI
Processing Levels
3
L3 (Pending)
2
L4
RTI
1
L1 (Pending)
0
RTI
Reset
Figure 4-14. Interrupt Processing Example
4.5.3
4.5.3.1
Wake Up from Stop or Wait Mode
CPU Wake Up from Stop or Wait Mode
Every I bit maskable interrupt request which is configured to be handled by the CPU is capable of waking
the MCU from stop or wait mode. To determine whether an I bit maskable interrupts is qualified to wake
up the CPU or not, the same settings as in normal run mode are applied during stop or wait mode:
• If the I bit in the CCR is set, all I bit maskable interrupts are masked from waking up the MCU.
• An I bit maskable interrupt is ignored if it is configured to a priority level below or equal to the
current IPL in CCR.
• I bit maskable interrupt requests which are configured to be handled by the XGATE module are not
capable of waking up the CPU.
The X bit maskable interrupt request can wake up the MCU from stop or wait mode at anytime, even if the
X bit in CCR is set. If the X bit maskable interrupt request is used to wake-up the MCU with the X bit in
the CCR set, the associated ISR is not called. The CPU then resumes program execution with the
instruction following the WAI or STOP instruction. This features works following the same rules like any
interrupt request, i.e. care must be taken that the X interrupt request used for wake-up remains active at
least until the system begins execution of the instruction following the WAI or STOP instruction;
otherwise, wake-up may not occur.
4.5.3.2
XGATE Wake Up from Stop or Wait Mode
Interrupt request channels which are configured to be handled by the XGATE module are capable of
waking up the XGATE module. Interrupt request channels handled by the XGATE module do not affect
the state of the CPU.
S12XS Family Reference Manual, Rev. 1.10
166
Freescale Semiconductor
Chapter 5
Background Debug Module (S12XBDMV2)
Table 5-1. Revision History
Revision
Number
Revision Date
V02.00
07 Mar 2006
- First version of S12XBDMV2
V02.01
14 May 2008
- Introduced standardized Revision History Table
5.1
Sections
Affected
Description of Changes
Introduction
This section describes the functionality of the background debug module (BDM) sub-block of the
HCS12X core platform.
The background debug module (BDM) sub-block is a single-wire, background debug system implemented
in on-chip hardware for minimal CPU intervention. All interfacing with the BDM is done via the BKGD
pin.
The BDM has enhanced capability for maintaining synchronization between the target and host while
allowing more flexibility in clock rates. This includes a sync signal to determine the communication rate
and a handshake signal to indicate when an operation is complete. The system is backwards compatible to
the BDM of the S12 family with the following exceptions:
• TAGGO command no longer supported by BDM
• External instruction tagging feature now part of DBG module
• BDM register map and register content extended/modified
• Global page access functionality
• Enabled but not active out of reset in emulation modes (if modes available)
• CLKSW bit set out of reset in emulation modes (if modes available).
• Family ID readable from firmware ROM at global address 0x7FFF0F (value for HCS12X devices
is 0xC1)
5.1.1
Features
The BDM includes these distinctive features:
• Single-wire communication with host development system
• Enhanced capability for allowing more flexibility in clock rates
• SYNC command to determine communication rate
• GO_UNTIL command
• Hardware handshake protocol to increase the performance of the serial communication
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
167
Background Debug Module (S12XBDMV2)
•
•
•
•
•
•
•
•
•
•
•
•
Active out of reset in special single chip mode
Nine hardware commands using free cycles, if available, for minimal CPU intervention
Hardware commands not requiring active BDM
14 firmware commands execute from the standard BDM firmware lookup table
Software control of BDM operation during wait mode
Software selectable clocks
Global page access functionality
Enabled but not active out of reset in emulation modes (if modes available)
CLKSW bit set out of reset in emulation modes (if modes available).
When secured, hardware commands are allowed to access the register space in special single chip
mode, if the non-volatile memory erase test fail.
Family ID readable from firmware ROM at global address 0x7FFF0F (value for HCS12X devices
is 0xC1)
BDM hardware commands are operational until system stop mode is entered (all bus masters are
in stop mode)
5.1.2
Modes of Operation
BDM is available in all operating modes but must be enabled before firmware commands are executed.
Some systems may have a control bit that allows suspending thefunction during background debug mode.
5.1.2.1
Regular Run Modes
All of these operations refer to the part in run mode and not being secured. The BDM does not provide
controls to conserve power during run mode.
• Normal modes
General operation of the BDM is available and operates the same in all normal modes.
• Special single chip mode
In special single chip mode, background operation is enabled and active out of reset. This allows
programming a system with blank memory.
• Emulation modes (if modes available)
In emulation mode, background operation is enabled but not active out of reset. This allows
debugging and programming a system in this mode more easily.
5.1.2.2
Secure Mode Operation
If the device is in secure mode, the operation of the BDM is reduced to a small subset of its regular run
mode operation. Secure operation prevents BDM and CPU accesses to non-volatile memory (Flash and/or
EEPROM) other than allowing erasure. For more information please see Section 5.4.1, “Security”.
S12XS Family Reference Manual, Rev. 1.10
168
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
5.1.2.3
Low-Power Modes
The BDM can be used until all bus masters (e.g., CPU or XGATE or others depending on which masters
are available on the SOC) are in stop mode. When CPU is in a low power mode (wait or stop mode) all
BDM firmware commands as well as the hardware BACKGROUND command can not be used
respectively are ignored. In this case the CPU can not enter BDM active mode, and only hardware read and
write commands are available. Also the CPU can not enter a low power mode during BDM active mode.
If all bus masters are in stop mode, the BDM clocks are stopped as well. When BDM clocks are disabled
and one of the bus masters exits from stop mode the BDM clocks will restart and BDM will have a soft
reset (clearing the instruction register, any command in progress and disable the ACK function). The BDM
is now ready to receive a new command.
5.1.3
Block Diagram
A block diagram of the BDM is shown in Figure 5-1.
Host
System
Serial
Interface
BKGD
Data
16-Bit Shift Register
Control
Register Block
Address
TRACE
BDMACT
Instruction Code
and
Execution
Bus Interface
and
Control Logic
Data
Control
Clocks
ENBDM
SDV
UNSEC
CLKSW
Standard BDM Firmware
LOOKUP TABLE
Secured BDM Firmware
LOOKUP TABLE
BDMSTS
Register
Figure 5-1. BDM Block Diagram
5.2
External Signal Description
A single-wire interface pin called the background debug interface (BKGD) pin is used to communicate
with the BDM system. During reset, this pin is a mode select input which selects between normal and
special modes of operation. After reset, this pin becomes the dedicated serial interface pin for the
background debug mode.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
169
Background Debug Module (S12XBDMV2)
5.3
Memory Map and Register Definition
5.3.1
Module Memory Map
Table 5-2 shows the BDM memory map when BDM is active.
Table 5-2. BDM Memory Map
5.3.2
Global Address
Module
Size
(Bytes)
0x7FFF00–0x7FFF0B
BDM registers
12
0x7FFF0C–0x7FFF0E
BDM firmware ROM
3
0x7FFF0F
Family ID (part of BDM firmware ROM)
1
0x7FFF10–0x7FFFFF
BDM firmware ROM
240
Register Descriptions
A summary of the registers associated with the BDM is shown in Figure 5-2. Registers are accessed by
host-driven communications to the BDM hardware using READ_BD and WRITE_BD commands.
Global
Address
Register
Name
0x7FFF00
Reserved
R
Bit 7
6
5
4
3
2
1
Bit 0
X
X
X
X
X
X
0
0
BDMACT
0
SDV
TRACE
UNSEC
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
CCR7
CCR6
CCR5
CCR4
CCR3
CCR2
CCR1
CCR0
W
0x7FFF01
BDMSTS
R
W
0x7FFF02
Reserved
R
ENBDM
CLKSW
W
0x7FFF03
Reserved
R
W
0x7FFF04
Reserved
R
W
0x7FFF05
Reserved
R
W
0x7FFF06
BDMCCRL R
W
= Unimplemented, Reserved
X
= Indeterminate
= Implemented (do not alter)
0
= Always read zero
Figure 5-2. BDM Register Summary
S12XS Family Reference Manual, Rev. 1.10
170
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
Global
Address
Register
Name
0x7FFF07
Bit 7
6
5
4
3
0
0
0
0
0
BGAE
BGP6
BGP5
BGP4
0
0
0
0
0
0
0
BDMCCRH R
2
1
Bit 0
CCR10
CCR9
CCR8
BGP3
BGP2
BGP1
BGP0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
0x7FFF08
BDMGPR
R
W
0x7FFF09
Reserved
R
W
0x7FFF0A
Reserved
R
W
0x7FFF0B
Reserved
R
W
= Unimplemented, Reserved
= Indeterminate
X
= Implemented (do not alter)
= Always read zero
0
Figure 5-2. BDM Register Summary (continued)
5.3.2.1
BDM Status Register (BDMSTS)
Register Global Address 0x7FFF01
7
R
W
ENBDM
6
5
4
3
BDMACT
0
SDV
TRACE
2
CLKSW
1
0
UNSEC
0
Reset
Special Single-Chip Mode
01
1
0
0
0
0
03
0
Emulation Modes
1
0
0
0
0
12
0
0
0
0
0
0
0
0
0
0
(if modes available)
All Other Modes
= Unimplemented, Reserved
= Implemented (do not alter)
0
= Always read zero
ENBDM is read as 1 by a debugging environment in special single chip mode when the device is not secured or secured but
fully erased (non-volatile memory). This is because the ENBDM bit is set by the standard firmware before a BDM command
can be fully transmitted and executed.
2 CLKSW is read as 1 by a debugging environment in emulation modes when the device is not secured and read as 0 when
secured if emulation modes available.
3 UNSEC is read as 1 by a debugging environment in special single chip mode when the device is secured and fully erased,
else it is 0 and can only be read if not secure (see also bit description).
1
Figure 5-3. BDM Status Register (BDMSTS)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
171
Background Debug Module (S12XBDMV2)
Read: All modes through BDM operation when not secured
Write: All modes through BDM operation when not secured, but subject to the following:
— ENBDM should only be set via a BDM hardware command if the BDM firmware commands
are needed. (This does not apply in special single chip and emulation modes).
— BDMACT can only be set by BDM hardware upon entry into BDM. It can only be cleared by
the standard BDM firmware lookup table upon exit from BDM active mode.
— CLKSW can only be written via BDM hardware WRITE_BD commands.
— All other bits, while writable via BDM hardware or standard BDM firmware write commands,
should only be altered by the BDM hardware or standard firmware lookup table as part of BDM
command execution.
Table 5-3. BDMSTS Field Descriptions
Field
Description
7
ENBDM
Enable BDM — This bit controls whether the BDM is enabled or disabled. When enabled, BDM can be made
active to allow firmware commands to be executed. When disabled, BDM cannot be made active but BDM
hardware commands are still allowed.
0 BDM disabled
1 BDM enabled
Note: ENBDM is set by the firmware out of reset in special single chip mode. In emulation modes (if modes
available) the ENBDM bit is set by BDM hardware out of reset. In special single chip mode with the device
secured, this bit will not be set by the firmware until after the non-volatile memory erase verify tests are
complete. In emulation modes (if modes available) with the device secured, the BDM operations are
blocked.
6
BDMACT
BDM Active Status — This bit becomes set upon entering BDM. The standard BDM firmware lookup table is
then enabled and put into the memory map. BDMACT is cleared by a carefully timed store instruction in the
standard BDM firmware as part of the exit sequence to return to user code and remove the BDM memory from
the map.
0 BDM not active
1 BDM active
4
SDV
Shift Data Valid — This bit is set and cleared by the BDM hardware. It is set after data has been transmitted as
part of a firmware or hardware read command or after data has been received as part of a firmware or hardware
write command. It is cleared when the next BDM command has been received or BDM is exited. SDV is used
by the standard BDM firmware to control program flow execution.
0 Data phase of command not complete
1 Data phase of command is complete
3
TRACE
TRACE1 BDM Firmware Command is Being Executed — This bit gets set when a BDM TRACE1 firmware
command is first recognized. It will stay set until BDM firmware is exited by one of the following BDM commands:
GO or GO_UNTIL.
0 TRACE1 command is not being executed
1 TRACE1 command is being executed
S12XS Family Reference Manual, Rev. 1.10
172
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
Table 5-3. BDMSTS Field Descriptions (continued)
Field
Description
2
CLKSW
Clock Switch — The CLKSW bit controls which clock the BDM operates with. It is only writable from a hardware
BDM command. A minimum delay of 150 cycles at the clock speed that is active during the data portion of the
command send to change the clock source should occur before the next command can be send. The delay
should be obtained no matter which bit is modified to effectively change the clock source (either PLLSEL bit or
CLKSW bit). This guarantees that the start of the next BDM command uses the new clock for timing subsequent
BDM communications.
Table 5-4 shows the resulting BDM clock source based on the CLKSW and the PLLSEL (PLL select in the CRG
module, the bit is part of the CLKSEL register) bits.
Note: The BDM alternate clock source can only be selected when CLKSW = 0 and PLLSEL = 1. The BDM serial
interface is now fully synchronized to the alternate clock source, when enabled. This eliminates frequency
restriction on the alternate clock which was required on previous versions. Refer to the device
specification to determine which clock connects to the alternate clock source input.
Note: If the acknowledge function is turned on, changing the CLKSW bit will cause the ACK to be at the new
rate for the write command which changes it.
Note: In emulation modes (if modes available), the CLKSW bit will be set out of RESET.
1
UNSEC
Unsecure — If the device is secured this bit is only writable in special single chip mode from the BDM secure
firmware. It is in a zero state as secure mode is entered so that the secure BDM firmware lookup table is enabled
and put into the memory map overlapping the standard BDM firmware lookup table.
The secure BDM firmware lookup table verifies that the non-volatile memories (e.g. on-chip EEPROM and/or
Flash EEPROM) are erased. This being the case, the UNSEC bit is set and the BDM program jumps to the start
of the standard BDM firmware lookup table and the secure BDM firmware lookup table is turned off. If the erase
test fails, the UNSEC bit will not be asserted.
0 System is in a secured mode.
1 System is in a unsecured mode.
Note: When UNSEC is set, security is off and the user can change the state of the secure bits in the on-chip
Flash EEPROM. Note that if the user does not change the state of the bits to “unsecured” mode, the
system will be secured again when it is next taken out of reset.After reset this bit has no meaning or effect
when the security byte in the Flash EEPROM is configured for unsecure mode.
Table 5-4. BDM Clock Sources
PLLSEL
CLKSW
BDMCLK
0
0
Bus clock dependent on oscillator
0
1
Bus clock dependent on oscillator
1
0
Alternate clock (refer to the device specification to determine the alternate clock source)
1
1
Bus clock dependent on the PLL
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
173
Background Debug Module (S12XBDMV2)
5.3.2.2
BDM CCR LOW Holding Register (BDMCCRL)
Register Global Address 0x7FFF06
7
6
5
4
3
2
1
0
CCR7
CCR6
CCR5
CCR4
CCR3
CCR2
CCR1
CCR0
Special Single-Chip Mode
1
1
0
0
1
0
0
0
All Other Modes
0
0
0
0
0
0
0
0
R
W
Reset
Figure 5-4. BDM CCR LOW Holding Register (BDMCCRL)
Read: All modes through BDM operation when not secured
Write: All modes through BDM operation when not secured
NOTE
When BDM is made active, the CPU stores the content of its CCRL register
in the BDMCCRL register. However, out of special single-chip reset, the
BDMCCRL is set to 0xD8 and not 0xD0 which is the reset value of the
CCRL register in this CPU mode. Out of reset in all other modes the
BDMCCRL register is read zero.
When entering background debug mode, the BDM CCR LOW holding register is used to save the low byte
of the condition code register of the user’s program. It is also used for temporary storage in the standard
BDM firmware mode. The BDM CCR LOW holding register can be written to modify the CCR value.
5.3.2.3
BDM CCR HIGH Holding Register (BDMCCRH)
Register Global Address 0x7FFF07
R
7
6
5
4
3
0
0
0
0
0
0
0
0
0
W
Reset
0
2
1
0
CCR10
CCR9
CCR8
0
0
0
= Unimplemented or Reserved
Figure 5-5. BDM CCR HIGH Holding Register (BDMCCRH)
Read: All modes through BDM operation when not secured
Write: All modes through BDM operation when not secured
When entering background debug mode, the BDM CCR HIGH holding register is used to save the high
byte of the condition code register of the user’s program. The BDM CCR HIGH holding register can be
written to modify the CCR value.
S12XS Family Reference Manual, Rev. 1.10
174
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
5.3.2.4
BDM Global Page Index Register (BDMGPR)
Register Global Address 0x7FFF08
R
W
Reset
7
6
5
4
3
2
1
0
BGAE
BGP6
BGP5
BGP4
BGP3
BGP2
BGP1
BGP0
0
0
0
0
0
0
0
0
Figure 5-6. BDM Global Page Register (BDMGPR)
Read: All modes through BDM operation when not secured
Write: All modes through BDM operation when not secured
Table 5-5. BDMGPR Field Descriptions
Field
Description
7
BGAE
BDM Global Page Access Enable Bit — BGAE enables global page access for BDM hardware and firmware
read/write instructions The BDM hardware commands used to access the BDM registers (READ_BD_ and
WRITE_BD_) can not be used for global accesses even if the BGAE bit is set.
0 BDM Global Access disabled
1 BDM Global Access enabled
6–0
BGP[6:0]
BDM Global Page Index Bits 6–0 — These bits define the extended address bits from 22 to 16. For more
detailed information regarding the global page window scheme, please refer to the S12X_MMC Block Guide.
5.3.3
Family ID Assignment
The family ID is a 8-bit value located in the firmware ROM (at global address: 0x7FFF0F). The read-only
value is a unique family ID which is 0xC1 for S12X devices.
5.4
Functional Description
The BDM receives and executes commands from a host via a single wire serial interface. There are two
types of BDM commands: hardware and firmware commands.
Hardware commands are used to read and write target system memory locations and to enter active
background debug mode, see Section 5.4.3, “BDM Hardware Commands”. Target system memory
includes all memory that is accessible by the CPU.
Firmware commands are used to read and write CPU resources and to exit from active background debug
mode, see Section 5.4.4, “Standard BDM Firmware Commands”. The CPU resources referred to are the
accumulator (D), X index register (X), Y index register (Y), stack pointer (SP), and program counter (PC).
Hardware commands can be executed at any time and in any mode excluding a few exceptions as
highlighted (see Section 5.4.3, “BDM Hardware Commands”) and in secure mode (see Section 5.4.1,
“Security”). Firmware commands can only be executed when the system is not secure and is in active
background debug mode (BDM).
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
175
Background Debug Module (S12XBDMV2)
5.4.1
Security
If the user resets into special single chip mode with the system secured, a secured mode BDM firmware
lookup table is brought into the map overlapping a portion of the standard BDM firmware lookup table.
The secure BDM firmware verifies that the on-chip non-volatile memory (e.g. EEPROM and Flash
EEPROM) is erased. This being the case, the UNSEC and ENBDM bit will get set. The BDM program
jumps to the start of the standard BDM firmware and the secured mode BDM firmware is turned off and
all BDM commands are allowed. If the non-volatile memory does not verify as erased, the BDM firmware
sets the ENBDM bit, without asserting UNSEC, and the firmware enters a loop. This causes the BDM
hardware commands to become enabled, but does not enable the firmware commands. This allows the
BDM hardware to be used to erase the non-volatile memory.
BDM operation is not possible in any other mode than special single chip mode when the device is secured.
The device can be unsecured via BDM serial interface in special single chip mode only. For more
information regarding security, please see the S12X_9SEC Block Guide.
5.4.2
Enabling and Activating BDM
The system must be in active BDM to execute standard BDM firmware commands. BDM can be activated
only after being enabled. BDM is enabled by setting the ENBDM bit in the BDM status (BDMSTS)
register. The ENBDM bit is set by writing to the BDM status (BDMSTS) register, via the single-wire
interface, using a hardware command such as WRITE_BD_BYTE.
After being enabled, BDM is activated by one of the following1:
• Hardware BACKGROUND command
• CPU BGND instruction
• External instruction tagging mechanism2
• Breakpoint force or tag mechanism2
When BDM is activated, the CPU finishes executing the current instruction and then begins executing the
firmware in the standard BDM firmware lookup table. When BDM is activated by a breakpoint, the type
of breakpoint used determines if BDM becomes active before or after execution of the next instruction.
NOTE
If an attempt is made to activate BDM before being enabled, the CPU
resumes normal instruction execution after a brief delay. If BDM is not
enabled, any hardware BACKGROUND commands issued are ignored by
the BDM and the CPU is not delayed.
In active BDM, the BDM registers and standard BDM firmware lookup table are mapped to addresses
0x7FFF00 to 0x7FFFFF. BDM registers are mapped to addresses 0x7FFF00 to 0x7FFF0B. The BDM uses
these registers which are readable anytime by the BDM. However, these registers are not readable by user
programs.
BDM is enabled and active immediately out of special single-chip reset.
2. This method is provided by the S12X_DBG module.
1.
S12XS Family Reference Manual, Rev. 1.10
176
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
5.4.3
BDM Hardware Commands
Hardware commands are used to read and write target system memory locations and to enter active
background debug mode. Target system memory includes all memory that is accessible by the CPU on the
SOC which can be on-chip RAM, non-volatile memory (e.g. EEPROM, Flash EEPROM), I/O and control
registers, and all external memory.
Hardware commands are executed with minimal or no CPU intervention and do not require the system to
be in active BDM for execution, although, they can still be executed in this mode. When executing a
hardware command, the BDM sub-block waits for a free bus cycle so that the background access does not
disturb the running application program. If a free cycle is not found within 128 clock cycles, the CPU is
momentarily frozen so that the BDM can steal a cycle. When the BDM finds a free cycle, the operation
does not intrude on normal CPU operation provided that it can be completed in a single cycle. However,
if an operation requires multiple cycles the CPU is frozen until the operation is complete, even though the
BDM found a free cycle.
The BDM hardware commands are listed in Table 5-6.
The READ_BD and WRITE_BD commands allow access to the BDM register locations. These locations
are not normally in the system memory map but share addresses with the application in memory. To
distinguish between physical memory locations that share the same address, BDM memory resources are
enabled just for the READ_BD and WRITE_BD access cycle. This allows the BDM to access BDM
locations unobtrusively, even if the addresses conflict with the application memory map.
Table 5-6. Hardware Commands
Opcode
(hex)
Data
BACKGROUND
90
None
Enter background mode if firmware is enabled. If enabled, an ACK will be
issued when the part enters active background mode.
ACK_ENABLE
D5
None
Enable Handshake. Issues an ACK pulse after the command is executed.
ACK_DISABLE
D6
None
Disable Handshake. This command does not issue an ACK pulse.
READ_BD_BYTE
E4
16-bit address Read from memory with standard BDM firmware lookup table in map.
16-bit data out Odd address data on low byte; even address data on high byte.
READ_BD_WORD
EC
16-bit address Read from memory with standard BDM firmware lookup table in map.
16-bit data out Must be aligned access.
READ_BYTE
E0
16-bit address Read from memory with standard BDM firmware lookup table out of map.
16-bit data out Odd address data on low byte; even address data on high byte.
READ_WORD
E8
16-bit address Read from memory with standard BDM firmware lookup table out of map.
16-bit data out Must be aligned access.
WRITE_BD_BYTE
C4
16-bit address Write to memory with standard BDM firmware lookup table in map.
16-bit data in Odd address data on low byte; even address data on high byte.
WRITE_BD_WORD
CC
16-bit address Write to memory with standard BDM firmware lookup table in map.
16-bit data in Must be aligned access.
WRITE_BYTE
C0
16-bit address Write to memory with standard BDM firmware lookup table out of map.
16-bit data in Odd address data on low byte; even address data on high byte.
Command
Description
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
177
Background Debug Module (S12XBDMV2)
Table 5-6. Hardware Commands (continued)
Command
WRITE_WORD
Opcode
(hex)
C8
Data
Description
16-bit address Write to memory with standard BDM firmware lookup table out of map.
16-bit data in Must be aligned access.
NOTE:
If enabled, ACK will occur when data is ready for transmission for all BDM READ commands and will occur after the write is
complete for all BDM WRITE commands.
5.4.4
Standard BDM Firmware Commands
Firmware commands are used to access and manipulate CPU resources. The system must be in active
BDM to execute standard BDM firmware commands, see Section 5.4.2, “Enabling and Activating BDM”.
Normal instruction execution is suspended while the CPU executes the firmware located in the standard
BDM firmware lookup table. The hardware command BACKGROUND is the usual way to activate BDM.
As the system enters active BDM, the standard BDM firmware lookup table and BDM registers become
visible in the on-chip memory map at 0x7FFF00–0x7FFFFF, and the CPU begins executing the standard
BDM firmware. The standard BDM firmware watches for serial commands and executes them as they are
received.
The firmware commands are shown in Table 5-7.
S12XS Family Reference Manual, Rev. 1.10
178
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
Table 5-7. Firmware Commands
Command1
Opcode
(hex)
Data
Description
READ_NEXT2
62
16-bit data out Increment X index register by 2 (X = X + 2), then read word X points to.
READ_PC
63
16-bit data out Read program counter.
READ_D
64
16-bit data out Read D accumulator.
READ_X
65
16-bit data out Read X index register.
READ_Y
66
16-bit data out Read Y index register.
READ_SP
67
16-bit data out Read stack pointer.
WRITE_NEXT<fhelvetica><stsuperscript>
42
16-bit data in
Increment X index register by 2 (X = X + 2), then write word to location
pointed to by X.
WRITE_PC
43
16-bit data in
Write program counter.
WRITE_D
44
16-bit data in
Write D accumulator.
WRITE_X
45
16-bit data in
Write X index register.
WRITE_Y
46
16-bit data in
Write Y index register.
WRITE_SP
47
16-bit data in
Write stack pointer.
GO
08
none
Go to user program. If enabled, ACK will occur when leaving active
background mode.
GO_UNTIL3
0C
none
Go to user program. If enabled, ACK will occur upon returning to active
background mode.
TRACE1
10
none
Execute one user instruction then return to active BDM. If enabled,
ACK will occur upon returning to active background mode.
TAGGO -> GO
18
none
(Previous enable tagging and go to user program.)
This command will be deprecated and should not be used anymore.
Opcode will be executed as a GO command.
1 If enabled, ACK will occur when data is ready for transmission for all BDM READ commands and will occur after the write is
complete for all BDM WRITE commands.
2 When the firmware command READ_NEXT or WRITE_NEXT is used to access the BDM address space the BDM resources
are accessed rather than user code. Writing BDM firmware is not possible.
System
stop disables the ACK function and ignored commands will not have an ACK-pulse (e.g., CPU in stop or wait mode).
3
The GO_UNTIL command will not get an Acknowledge if CPU executes the wait or stop instruction before the “UNTIL”
condition (BDM active again) is reached (see Section 5.4.7, “Serial Interface Hardware Handshake Protocol” last Note).
5.4.5
BDM Command Structure
Hardware and firmware BDM commands start with an 8-bit opcode followed by a 16-bit address and/or a
16-bit data word depending on the command. All the read commands return 16 bits of data despite the byte
or word implication in the command name.
8-bit reads return 16-bits of data, of which, only one byte will contain valid
data. If reading an even address, the valid data will appear in the MSB. If
reading an odd address, the valid data will appear in the LSB.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
179
Background Debug Module (S12XBDMV2)
16-bit misaligned reads and writes are generally not allowed. If attempted
by BDM hardware command, the BDM will ignore the least significant bit
of the address and will assume an even address from the remaining bits.
For devices with external bus:
The following cycle count information is only valid when the external wait
function is not used (see wait bit of EBI sub-block). During an external wait
the BDM can not steal a cycle. Hence be careful with the external wait
function if the BDM serial interface is much faster than the bus, because of
the BDM soft-reset after time-out (see Section 5.4.11, “Serial
Communication Time Out”).
For hardware data read commands, the external host must wait at least 150 bus clock cycles after sending
the address before attempting to obtain the read data. This is to be certain that valid data is available in the
BDM shift register, ready to be shifted out. For hardware write commands, the external host must wait
150 bus clock cycles after sending the data to be written before attempting to send a new command. This
is to avoid disturbing the BDM shift register before the write has been completed. The 150 bus clock cycle
delay in both cases includes the maximum 128 cycle delay that can be incurred as the BDM waits for a
free cycle before stealing a cycle.
For firmware read commands, the external host should wait at least 48 bus clock cycles after sending the
command opcode and before attempting to obtain the read data. This includes the potential of extra cycles
when the access is external and stretched (+1 to maximum +7 cycles) or to registers of the PRU (port
replacement unit) in emulation modes (if modes available). The 48 cycle wait allows enough time for the
requested data to be made available in the BDM shift register, ready to be shifted out.
NOTE
This timing has increased from previous BDM modules due to the new
capability in which the BDM serial interface can potentially run faster than
the bus. On previous BDM modules this extra time could be hidden within
the serial time.
For firmware write commands, the external host must wait 36 bus clock cycles after sending the data to be
written before attempting to send a new command. This is to avoid disturbing the BDM shift register
before the write has been completed.
The external host should wait at least for 76 bus clock cycles after a TRACE1 or GO command before
starting any new serial command. This is to allow the CPU to exit gracefully from the standard BDM
firmware lookup table and resume execution of the user code. Disturbing the BDM shift register
prematurely may adversely affect the exit from the standard BDM firmware lookup table.
NOTE
If the bus rate of the target processor is unknown or could be changing or the
external wait function is used, it is recommended that the ACK
(acknowledge function) is used to indicate when an operation is complete.
When using ACK, the delay times are automated.
S12XS Family Reference Manual, Rev. 1.10
180
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
Figure 5-7 represents the BDM command structure. The command blocks illustrate a series of eight bit
times starting with a falling edge. The bar across the top of the blocks indicates that the BKGD line idles
in the high state. The time for an 8-bit command is 8 × 16 target clock cycles.1
Hardware
Read
8 Bits
AT ~16 TC/Bit
16 Bits
AT ~16 TC/Bit
Command
Address
150-BC
Delay
16 Bits
AT ~16 TC/Bit
Data
Next
Command
150-BC
Delay
Hardware
Write
Command
Address
Data
Next
Command
48-BC
DELAY
Firmware
Read
Command
Next
Command
Data
36-BC
DELAY
Firmware
Write
Command
Data
Next
Command
76-BC
Delay
GO,
TRACE
Command
Next
Command
BC = Bus Clock Cycles
TC = Target Clock Cycles
Figure 5-7. BDM Command Structure
5.4.6
BDM Serial Interface
The BDM communicates with external devices serially via the BKGD pin. During reset, this pin is a mode
select input which selects between normal and special modes of operation. After reset, this pin becomes
the dedicated serial interface pin for the BDM.
The BDM serial interface is timed using the clock selected by the CLKSW bit in the status register see
Section 5.3.2.1, “BDM Status Register (BDMSTS)”. This clock will be referred to as the target clock in
the following explanation.
The BDM serial interface uses a clocking scheme in which the external host generates a falling edge on
the BKGD pin to indicate the start of each bit time. This falling edge is sent for every bit whether data is
transmitted or received. Data is transferred most significant bit (MSB) first at 16 target clock cycles per
bit. The interface times out if 512 clock cycles occur between falling edges from the host.
The BKGD pin is a pseudo open-drain pin and has an weak on-chip active pull-up that is enabled at all
times. It is assumed that there is an external pull-up and that drivers connected to BKGD do not typically
drive the high level. Since R-C rise time could be unacceptably long, the target system and host provide
brief driven-high (speedup) pulses to drive BKGD to a logic 1. The source of this speedup pulse is the host
for transmit cases and the target for receive cases.
1.
Target clock cycles are cycles measured using the target MCU’s serial clock rate. See Section 5.4.6, “BDM Serial Interface”
and Section 5.3.2.1, “BDM Status Register (BDMSTS)” for information on how serial clock rate is selected.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
181
Background Debug Module (S12XBDMV2)
The timing for host-to-target is shown in Figure 5-8 and that of target-to-host in Figure 5-9 and
Figure 5-10. All four cases begin when the host drives the BKGD pin low to generate a falling edge. Since
the host and target are operating from separate clocks, it can take the target system up to one full clock
cycle to recognize this edge. The target measures delays from this perceived start of the bit time while the
host measures delays from the point it actually drove BKGD low to start the bit up to one target clock cycle
earlier. Synchronization between the host and target is established in this manner at the start of every bit
time.
Figure 5-8 shows an external host transmitting a logic 1 and transmitting a logic 0 to the BKGD pin of a
target system. The host is asynchronous to the target, so there is up to a one clock-cycle delay from the
host-generated falling edge to where the target recognizes this edge as the beginning of the bit time. Ten
target clock cycles later, the target senses the bit level on the BKGD pin. Internal glitch detect logic
requires the pin be driven high no later that eight target clock cycles after the falling edge for a logic 1
transmission.
Since the host drives the high speedup pulses in these two cases, the rising edges look like digitally driven
signals.
BDM Clock
(Target MCU)
Host
Transmit 1
Host
Transmit 0
Perceived
Start of Bit Time
Target Senses Bit
10 Cycles
Synchronization
Uncertainty
Earliest
Start of
Next Bit
Figure 5-8. BDM Host-to-Target Serial Bit Timing
The receive cases are more complicated. Figure 5-9 shows the host receiving a logic 1 from the target
system. Since the host is asynchronous to the target, there is up to one clock-cycle delay from the hostgenerated falling edge on BKGD to the perceived start of the bit time in the target. The host holds the
BKGD pin low long enough for the target to recognize it (at least two target clock cycles). The host must
release the low drive before the target drives a brief high speedup pulse seven target clock cycles after the
perceived start of the bit time. The host should sample the bit level about 10 target clock cycles after it
started the bit time.
S12XS Family Reference Manual, Rev. 1.10
182
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
BDM Clock
(Target MCU)
Host
Drive to
BKGD Pin
Target System
Speedup
Pulse
High-Impedance
High-Impedance
High-Impedance
Perceived
Start of Bit Time
R-C Rise
BKGD Pin
10 Cycles
10 Cycles
Host Samples
BKGD Pin
Earliest
Start of
Next Bit
Figure 5-9. BDM Target-to-Host Serial Bit Timing (Logic 1)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
183
Background Debug Module (S12XBDMV2)
Figure 5-10 shows the host receiving a logic 0 from the target. Since the host is asynchronous to the target,
there is up to a one clock-cycle delay from the host-generated falling edge on BKGD to the start of the bit
time as perceived by the target. The host initiates the bit time but the target finishes it. Since the target
wants the host to receive a logic 0, it drives the BKGD pin low for 13 target clock cycles then briefly drives
it high to speed up the rising edge. The host samples the bit level about 10 target clock cycles after starting
the bit time.
BDM Clock
(Target MCU)
Host
Drive to
BKGD Pin
High-Impedance
Speedup Pulse
Target System
Drive and
Speedup Pulse
Perceived
Start of Bit Time
BKGD Pin
10 Cycles
10 Cycles
Host Samples
BKGD Pin
Earliest
Start of
Next Bit
Figure 5-10. BDM Target-to-Host Serial Bit Timing (Logic 0)
5.4.7
Serial Interface Hardware Handshake Protocol
BDM commands that require CPU execution are ultimately treated at the MCU bus rate. Since the BDM
clock source can be asynchronously related to the bus frequency, when CLKSW = 0, it is very helpful to
provide a handshake protocol in which the host could determine when an issued command is executed by
the CPU. The alternative is to always wait the amount of time equal to the appropriate number of cycles at
the slowest possible rate the clock could be running. This sub-section will describe the hardware
handshake protocol.
The hardware handshake protocol signals to the host controller when an issued command was successfully
executed by the target. This protocol is implemented by a 16 serial clock cycle low pulse followed by a
brief speedup pulse in the BKGD pin. This pulse is generated by the target MCU when a command, issued
by the host, has been successfully executed (see Figure 5-11). This pulse is referred to as the ACK pulse.
After the ACK pulse has finished: the host can start the bit retrieval if the last issued command was a read
command, or start a new command if the last command was a write command or a control command
(BACKGROUND, GO, GO_UNTIL or TRACE1). The ACK pulse is not issued earlier than 32 serial clock
cycles after the BDM command was issued. The end of the BDM command is assumed to be the 16th tick
of the last bit. This minimum delay assures enough time for the host to perceive the ACK pulse. Note also
that, there is no upper limit for the delay between the command and the related ACK pulse, since the
command execution depends upon the CPU bus frequency, which in some cases could be very slow
S12XS Family Reference Manual, Rev. 1.10
184
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
compared to the serial communication rate. This protocol allows a great flexibility for the POD designers,
since it does not rely on any accurate time measurement or short response time to any event in the serial
communication.
BDM Clock
(Target MCU)
16 Cycles
Target
Transmits
ACK Pulse
High-Impedance
High-Impedance
32 Cycles
Speedup Pulse
Minimum Delay
From the BDM Command
BKGD Pin
Earliest
Start of
Next Bit
16th Tick of the
Last Command Bit
Figure 5-11. Target Acknowledge Pulse (ACK)
NOTE
If the ACK pulse was issued by the target, the host assumes the previous
command was executed. If the CPU enters wait or stop prior to executing a
hardware command, the ACK pulse will not be issued meaning that the
BDM command was not executed. After entering wait or stop mode, the
BDM command is no longer pending.
Figure 5-12 shows the ACK handshake protocol in a command level timing diagram. The READ_BYTE
instruction is used as an example. First, the 8-bit instruction opcode is sent by the host, followed by the
address of the memory location to be read. The target BDM decodes the instruction. A bus cycle is grabbed
(free or stolen) by the BDM and it executes the READ_BYTE operation. Having retrieved the data, the
BDM issues an ACK pulse to the host controller, indicating that the addressed byte is ready to be retrieved.
After detecting the ACK pulse, the host initiates the byte retrieval process. Note that data is sent in the form
of a word and the host needs to determine which is the appropriate byte based on whether the address was
odd or even.
Target
BKGD Pin READ_BYTE
Host
Byte Address
Host
(2) Bytes are
Retrieved
New BDM
Command
Host
Target
Target
BDM Issues the
ACK Pulse (out of scale)
BDM Decodes
the Command
BDM Executes the
READ_BYTE Command
Figure 5-12. Handshake Protocol at Command Level
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
185
Background Debug Module (S12XBDMV2)
Differently from the normal bit transfer (where the host initiates the transmission), the serial interface ACK
handshake pulse is initiated by the target MCU by issuing a negative edge in the BKGD pin. The hardware
handshake protocol in Figure 5-11 specifies the timing when the BKGD pin is being driven, so the host
should follow this timing constraint in order to avoid the risk of an electrical conflict in the BKGD pin.
NOTE
The only place the BKGD pin can have an electrical conflict is when one
side is driving low and the other side is issuing a speedup pulse (high). Other
“highs” are pulled rather than driven. However, at low rates the time of the
speedup pulse can become lengthy and so the potential conflict time
becomes longer as well.
The ACK handshake protocol does not support nested ACK pulses. If a BDM command is not
acknowledge by an ACK pulse, the host needs to abort the pending command first in order to be able to
issue a new BDM command. When the CPU enters wait or stop while the host issues a hardware command
(e.g., WRITE_BYTE), the target discards the incoming command due to the wait or stop being detected.
Therefore, the command is not acknowledged by the target, which means that the ACK pulse will not be
issued in this case. After a certain time the host (not aware of stop or wait) should decide to abort any
possible pending ACK pulse in order to be sure a new command can be issued. Therefore, the protocol
provides a mechanism in which a command, and its corresponding ACK, can be aborted.
NOTE
The ACK pulse does not provide a time out. This means for the GO_UNTIL
command that it can not be distinguished if a stop or wait has been executed
(command discarded and ACK not issued) or if the “UNTIL” condition
(BDM active) is just not reached yet. Hence in any case where the ACK
pulse of a command is not issued the possible pending command should be
aborted before issuing a new command. See the handshake abort procedure
described in Section 5.4.8, “Hardware Handshake Abort Procedure”.
5.4.8
Hardware Handshake Abort Procedure
The abort procedure is based on the SYNC command. In order to abort a command, which had not issued
the corresponding ACK pulse, the host controller should generate a low pulse in the BKGD pin by driving
it low for at least 128 serial clock cycles and then driving it high for one serial clock cycle, providing a
speedup pulse. By detecting this long low pulse in the BKGD pin, the target executes the SYNC protocol,
see Section 5.4.9, “SYNC — Request Timed Reference Pulse”, and assumes that the pending command
and therefore the related ACK pulse, are being aborted. Therefore, after the SYNC protocol has been
completed the host is free to issue new BDM commands. For Firmware READ or WRITE commands it
can not be guaranteed that the pending command is aborted when issuing a SYNC before the
corresponding ACK pulse. There is a short latency time from the time the READ or WRITE access begins
until it is finished and the corresponding ACK pulse is issued. The latency time depends on the firmware
READ or WRITE command that is issued and if the serial interface is running on a different clock rate
than the bus. When the SYNC command starts during this latency time the READ or WRITE command
will not be aborted, but the corresponding ACK pulse will be aborted. A pending GO, TRACE1 or
S12XS Family Reference Manual, Rev. 1.10
186
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
GO_UNTIL command can not be aborted. Only the corresponding ACK pulse can be aborted by the
SYNC command.
Although it is not recommended, the host could abort a pending BDM command by issuing a low pulse in
the BKGD pin shorter than 128 serial clock cycles, which will not be interpreted as the SYNC command.
The ACK is actually aborted when a negative edge is perceived by the target in the BKGD pin. The short
abort pulse should have at least 4 clock cycles keeping the BKGD pin low, in order to allow the negative
edge to be detected by the target. In this case, the target will not execute the SYNC protocol but the pending
command will be aborted along with the ACK pulse. The potential problem with this abort procedure is
when there is a conflict between the ACK pulse and the short abort pulse. In this case, the target may not
perceive the abort pulse. The worst case is when the pending command is a read command (i.e.,
READ_BYTE). If the abort pulse is not perceived by the target the host will attempt to send a new
command after the abort pulse was issued, while the target expects the host to retrieve the accessed
memory byte. In this case, host and target will run out of synchronism. However, if the command to be
aborted is not a read command the short abort pulse could be used. After a command is aborted the target
assumes the next negative edge, after the abort pulse, is the first bit of a new BDM command.
NOTE
The details about the short abort pulse are being provided only as a reference
for the reader to better understand the BDM internal behavior. It is not
recommended that this procedure be used in a real application.
Since the host knows the target serial clock frequency, the SYNC command (used to abort a command)
does not need to consider the lower possible target frequency. In this case, the host could issue a SYNC
very close to the 128 serial clock cycles length. Providing a small overhead on the pulse length in order to
assure the SYNC pulse will not be misinterpreted by the target. See Section 5.4.9, “SYNC — Request
Timed Reference Pulse”.
Figure 5-13 shows a SYNC command being issued after a READ_BYTE, which aborts the READ_BYTE
command. Note that, after the command is aborted a new command could be issued by the host computer.
READ_BYTE CMD is Aborted
by the SYNC Request
(Out of Scale)
BKGD Pin READ_BYTE
Host
Memory Address
Target
BDM Decode
and Starts to Execute
the READ_BYTE Command
SYNC Response
From the Target
(Out of Scale)
READ_STATUS
Host
Target
New BDM Command
Host
Target
New BDM Command
Figure 5-13. ACK Abort Procedure at the Command Level
NOTE
Figure 5-13 does not represent the signals in a true timing scale
Figure 5-14 shows a conflict between the ACK pulse and the SYNC request pulse. This conflict could
occur if a POD device is connected to the target BKGD pin and the target is already in debug active mode.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
187
Background Debug Module (S12XBDMV2)
Consider that the target CPU is executing a pending BDM command at the exact moment the POD is being
connected to the BKGD pin. In this case, an ACK pulse is issued along with the SYNC command. In this
case, there is an electrical conflict between the ACK speedup pulse and the SYNC pulse. Since this is not
a probable situation, the protocol does not prevent this conflict from happening.
At Least 128 Cycles
BDM Clock
(Target MCU)
ACK Pulse
Target MCU
Drives to
BKGD Pin
Host
Drives SYNC
To BKGD Pin
High-Impedance
Host and
Target Drive
to BKGD Pin
Electrical Conflict
Speedup Pulse
Host SYNC Request Pulse
BKGD Pin
16 Cycles
Figure 5-14. ACK Pulse and SYNC Request Conflict
NOTE
This information is being provided so that the MCU integrator will be aware
that such a conflict could eventually occur.
The hardware handshake protocol is enabled by the ACK_ENABLE and disabled by the ACK_DISABLE
BDM commands. This provides backwards compatibility with the existing POD devices which are not
able to execute the hardware handshake protocol. It also allows for new POD devices, that support the
hardware handshake protocol, to freely communicate with the target device. If desired, without the need
for waiting for the ACK pulse.
The commands are described as follows:
• ACK_ENABLE — enables the hardware handshake protocol. The target will issue the ACK pulse
when a CPU command is executed by the CPU. The ACK_ENABLE command itself also has the
ACK pulse as a response.
• ACK_DISABLE — disables the ACK pulse protocol. In this case, the host needs to use the worst
case delay time at the appropriate places in the protocol.
The default state of the BDM after reset is hardware handshake protocol disabled.
All the read commands will ACK (if enabled) when the data bus cycle has completed and the data is then
ready for reading out by the BKGD serial pin. All the write commands will ACK (if enabled) after the data
has been received by the BDM through the BKGD serial pin and when the data bus cycle is complete. See
Section 5.4.3, “BDM Hardware Commands” and Section 5.4.4, “Standard BDM Firmware Commands”
for more information on the BDM commands.
S12XS Family Reference Manual, Rev. 1.10
188
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
The ACK_ENABLE sends an ACK pulse when the command has been completed. This feature could be
used by the host to evaluate if the target supports the hardware handshake protocol. If an ACK pulse is
issued in response to this command, the host knows that the target supports the hardware handshake
protocol. If the target does not support the hardware handshake protocol the ACK pulse is not issued. In
this case, the ACK_ENABLE command is ignored by the target since it is not recognized as a valid
command.
The BACKGROUND command will issue an ACK pulse when the CPU changes from normal to
background mode. The ACK pulse related to this command could be aborted using the SYNC command.
The GO command will issue an ACK pulse when the CPU exits from background mode. The ACK pulse
related to this command could be aborted using the SYNC command.
The GO_UNTIL command is equivalent to a GO command with exception that the ACK pulse, in this
case, is issued when the CPU enters into background mode. This command is an alternative to the GO
command and should be used when the host wants to trace if a breakpoint match occurs and causes the
CPU to enter active background mode. Note that the ACK is issued whenever the CPU enters BDM, which
could be caused by a breakpoint match or by a BGND instruction being executed. The ACK pulse related
to this command could be aborted using the SYNC command.
The TRACE1 command has the related ACK pulse issued when the CPU enters background active mode
after one instruction of the application program is executed. The ACK pulse related to this command could
be aborted using the SYNC command.
5.4.9
SYNC — Request Timed Reference Pulse
The SYNC command is unlike other BDM commands because the host does not necessarily know the
correct communication speed to use for BDM communications until after it has analyzed the response to
the SYNC command. To issue a SYNC command, the host should perform the following steps:
1. Drive the BKGD pin low for at least 128 cycles at the lowest possible BDM serial communication
frequency (the lowest serial communication frequency is determined by the crystal oscillator or the
clock chosen by CLKSW.)
2. Drive BKGD high for a brief speedup pulse to get a fast rise time (this speedup pulse is typically
one cycle of the host clock.)
3. Remove all drive to the BKGD pin so it reverts to high impedance.
4. Listen to the BKGD pin for the sync response pulse.
Upon detecting the SYNC request from the host, the target performs the following steps:
1. Discards any incomplete command received or bit retrieved.
2. Waits for BKGD to return to a logic one.
3. Delays 16 cycles to allow the host to stop driving the high speedup pulse.
4. Drives BKGD low for 128 cycles at the current BDM serial communication frequency.
5. Drives a one-cycle high speedup pulse to force a fast rise time on BKGD.
6. Removes all drive to the BKGD pin so it reverts to high impedance.
The host measures the low time of this 128 cycle SYNC response pulse and determines the correct speed
for subsequent BDM communications. Typically, the host can determine the correct communication speed
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
189
Background Debug Module (S12XBDMV2)
within a few percent of the actual target speed and the communication protocol can easily tolerate speed
errors of several percent.
As soon as the SYNC request is detected by the target, any partially received command or bit retrieved is
discarded. This is referred to as a soft-reset, equivalent to a time-out in the serial communication. After the
SYNC response, the target will consider the next negative edge (issued by the host) as the start of a new
BDM command or the start of new SYNC request.
Another use of the SYNC command pulse is to abort a pending ACK pulse. The behavior is exactly the
same as in a regular SYNC command. Note that one of the possible causes for a command to not be
acknowledged by the target is a host-target synchronization problem. In this case, the command may not
have been understood by the target and so an ACK response pulse will not be issued.
5.4.10
Instruction Tracing
When a TRACE1 command is issued to the BDM in active BDM, the CPU exits the standard BDM
firmware and executes a single instruction in the user code. Once this has occurred, the CPU is forced to
return to the standard BDM firmware and the BDM is active and ready to receive a new command. If the
TRACE1 command is issued again, the next user instruction will be executed. This facilitates stepping or
tracing through the user code one instruction at a time.
If an interrupt is pending when a TRACE1 command is issued, the interrupt stacking operation occurs but
no user instruction is executed. Once back in standard BDM firmware execution, the program counter
points to the first instruction in the interrupt service routine.
Be aware when tracing through the user code that the execution of the user code is done step by step but
all peripherals are free running. Hence possible timing relations between CPU code execution and
occurrence of events of other peripherals no longer exist.
Do not trace the CPU instruction BGND used for soft breakpoints. Tracing the BGND instruction will
result in a return address pointing to BDM firmware address space.
When tracing through user code which contains stop or wait instructions the following will happen when
the stop or wait instruction is traced:
The CPU enters stop or wait mode and the TRACE1 command can not be finished before leaving
the low power mode. This is the case because BDM active mode can not be entered after CPU
executed the stop instruction. However all BDM hardware commands except the BACKGROUND
command are operational after tracing a stop or wait instruction and still being in stop or wait
mode. If system stop mode is entered (all bus masters are in stop mode) no BDM command is
operational.
As soon as stop or wait mode is exited the CPU enters BDM active mode and the saved PC value
points to the entry of the corresponding interrupt service routine.
In case the handshake feature is enabled the corresponding ACK pulse of the TRACE1 command
will be discarded when tracing a stop or wait instruction. Hence there is no ACK pulse when BDM
active mode is entered as part of the TRACE1 command after CPU exited from stop or wait mode.
All valid commands sent during CPU being in stop or wait mode or after CPU exited from stop or
wait mode will have an ACK pulse. The handshake feature becomes disabled only when system
S12XS Family Reference Manual, Rev. 1.10
190
Freescale Semiconductor
Background Debug Module (S12XBDMV2)
stop mode has been reached. Hence after a system stop mode the handshake feature must be
enabled again by sending the ACK_ENABLE command.
5.4.11
Serial Communication Time Out
The host initiates a host-to-target serial transmission by generating a falling edge on the BKGD pin. If
BKGD is kept low for more than 128 target clock cycles, the target understands that a SYNC command
was issued. In this case, the target will keep waiting for a rising edge on BKGD in order to answer the
SYNC request pulse. If the rising edge is not detected, the target will keep waiting forever without any
time-out limit.
Consider now the case where the host returns BKGD to logic one before 128 cycles. This is interpreted as
a valid bit transmission, and not as a SYNC request. The target will keep waiting for another falling edge
marking the start of a new bit. If, however, a new falling edge is not detected by the target within 512 clock
cycles since the last falling edge, a time-out occurs and the current command is discarded without affecting
memory or the operating mode of the MCU. This is referred to as a soft-reset.
If a read command is issued but the data is not retrieved within 512 serial clock cycles, a soft-reset will
occur causing the command to be disregarded. The data is not available for retrieval after the time-out has
occurred. This is the expected behavior if the handshake protocol is not enabled. However, consider the
behavior where the BDM is running in a frequency much greater than the CPU frequency. In this case, the
command could time out before the data is ready to be retrieved. In order to allow the data to be retrieved
even with a large clock frequency mismatch (between BDM and CPU) when the hardware handshake
protocol is enabled, the time out between a read command and the data retrieval is disabled. Therefore, the
host could wait for more then 512 serial clock cycles and still be able to retrieve the data from an issued
read command. However, once the handshake pulse (ACK pulse) is issued, the time-out feature is reactivated, meaning that the target will time out after 512 clock cycles. Therefore, the host needs to retrieve
the data within a 512 serial clock cycles time frame after the ACK pulse had been issued. After that period,
the read command is discarded and the data is no longer available for retrieval. Any negative edge in the
BKGD pin after the time-out period is considered to be a new command or a SYNC request.
Note that whenever a partially issued command, or partially retrieved data, has occurred the time out in the
serial communication is active. This means that if a time frame higher than 512 serial clock cycles is
observed between two consecutive negative edges and the command being issued or data being retrieved
is not complete, a soft-reset will occur causing the partially received command or data retrieved to be
disregarded. The next negative edge in the BKGD pin, after a soft-reset has occurred, is considered by the
target as the start of a new BDM command, or the start of a SYNC request pulse.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
191
Background Debug Module (S12XBDMV2)
S12XS Family Reference Manual, Rev. 1.10
192
Freescale Semiconductor
Chapter 6
S12X Debug (S12XDBGV3) Module
Table 6-1. Revision History
Revision
Number
Revision Date
Sections
Affected
V03.20
14 Sep 2007
6.3.2.7/6-203
- Clarified reserved State Sequencer encodings.
V03.21
23 Oct 2007
6.4.2.2/6-216
6.4.2.4/6-217
- Added single databyte comparison limitation information
- Added statement about interrupt vector fetches whilst tagging.
V03.22
12 Nov 2007
6.4.5.2/6-221
6.4.5.5/6-225
- Removed LOOP1 tracing restriction NOTE.
- Added pin reset effect NOTE.
V03.23
13 Nov 2007
General
V03.24
04 Jan 2008
6.4.5.3/6-223
V03.25
14 May 2008
6.1
Description of Changes
- Text readability improved, typo removed.
- Corrected bit name.
- Updated Revision History Table format. Corrected other paragraph formats.
Introduction
The S12XDBG module provides an on-chip trace buffer with flexible triggering capability to allow nonintrusive debug of application software. The S12XDBG module is optimized for the S12X 16-bit
architecture and allows debugging of CPU12X module operations.
Typically the S12XDBG module is used in conjunction with the S12XBDM module, whereby the user
configures the S12XDBG module for a debugging session over the BDM interface. Once configured the
S12XDBG module is armed and the device leaves BDM Mode returning control to the user program,
which is then monitored by the S12XDBG module. Alternatively the S12XDBG module can be configured
over a serial interface using SWI routines.
6.1.1
Glossary
Table 6-2. Glossary Of Terms
Term
Definition
COF
Change Of Flow.
Change in the program flow due to a conditional branch, indexed jump or interrupt
BDM
Background Debug Mode
DUG
Device User Guide, describing the features of the device into which the DBG is integrated
WORD
16 bit data entity
Data Line
64 bit data entity
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
193
S12X Debug (S12XDBGV3) Module
Table 6-2. Glossary Of Terms (continued)
Term
Definition
CPU
CPU12X module
Tag
Tags can be attached to CPU opcodes as they enter the instruction pipe. If the tagged opcode reaches the
execution stage a tag hit occurs.
6.1.2
Overview
The comparators monitor the bus activity of the CPU12X. When a match occurs the control logic can
trigger the state sequencer to a new state. On a transition to the Final State, bus tracing is triggered and/or
a breakpoint can be generated.
Independent of comparator matches a transition to Final State with associated tracing and breakpoint can
be triggered by writing to the TRIG control bit.
The trace buffer is visible through a 2-byte window in the register address map and can be read out using
standard 16-bit word reads. Tracing is disabled when the MCU system is secured.
6.1.3
•
•
•
•
•
•
Features
Four comparators (A, B, C, and D)
— Comparators A and C compare the full address bus and full 16-bit data bus
— Comparators A and C feature a data bus mask register
— Comparators B and D compare the full address bus only
— Each comparator can be configured to monitor CPU12X buses
— Each comparator features selection of read or write access cycles
— Comparators B and D allow selection of byte or word access cycles
— Comparisons can be used as triggers for the state sequencer
Three comparator modes
— Simple address/data comparator match mode
— Inside address range mode, Addmin ≤ Address ≤ Addmax
— Outside address range match mode, Address < Addmin or Address > Addmax
Two types of triggers
— Tagged — This triggers just before a specific instruction begins execution
— Force — This triggers on the first instruction boundary after a match occurs.
The following types of breakpoints
— CPU12X breakpoint entering BDM on breakpoint (BDM)
— CPU12X breakpoint executing SWI on breakpoint (SWI)
TRIG Immediate software trigger independent of comparators
Four trace modes
— Normal: change of flow (COF) PC information is stored (see Section 6.4.5.2.1) for change of
flow definition.
S12XS Family Reference Manual, Rev. 1.10
194
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
— Loop1: same as Normal but inhibits consecutive duplicate source address entries
— Detail: address and data for all cycles except free cycles and opcode fetches are stored
— Pure PC: All program counter addresses are stored.
4-stage state sequencer for trace buffer control
— Tracing session trigger linked to Final State of state sequencer
— Begin, End, and Mid alignment of tracing to trigger
•
6.1.4
Modes of Operation
The S12XDBG module can be used in all MCU functional modes.
During BDM hardware accesses and whilst the BDM module is active, CPU12X monitoring is disabled.
Thus breakpoints, comparators, and CPU12X bus tracing are disabled . When the CPU12X enters active
BDM Mode through a BACKGROUND command, with the S12XDBG module armed, the S12XDBG
remains armed.
The S12XDBG module tracing is disabled if the MCU is secure. However, breakpoints can still be
generated if the MCU is secure.
Table 6-3. Mode Dependent Restriction Summary
BDM
Enable
BDM
Active
MCU
Secure
Comparator
Matches Enabled
Breakpoints
Possible
Tagging
Possible
Tracing
Possible
x
x
1
Yes
Yes
Yes
No
0
0
0
Yes
Only SWI
Yes
Yes
0
1
0
1
0
0
Yes
Yes
Yes
Yes
1
1
0
No
No
No
No
Active BDM not possible when not enabled
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
195
S12X Debug (S12XDBGV3) Module
6.1.5
Block Diagram
TAGS
TAGHITS
BREAKPOINT REQUESTS
S12XCPU
SECURE
COMPARATOR B
COMPARATOR C
COMPARATOR D
MATCH0
COMPARATOR
MATCH CONTROL
COMPARATOR A
BUS INTERFACE
S12XCPU BUS
TAG &
TRIGGER
CONTROL
LOGIC
MATCH1
TRIGGER
STATE
STATE SEQUENCER
STATE
MATCH2
MATCH3
TRACE
CONTROL
TRIGGER
TRACE BUFFER
READ TRACE DATA (DBG READ DATA BUS)
Figure 6-1. Debug Module Block Diagram
6.2
External Signal Description
The S12XDBG sub-module features no external signals.
6.3
6.3.1
Memory Map and Registers
Module Memory Map
A summary of the registers associated with the S12XDBG sub-block is shown in Table 6-2. Detailed
descriptions of the registers and bits are given in the subsections that follow.
Address
Name
Bit 7
0x0020
DBGC1
R
W
0x0021
DBGSR
R
W
0x0022
DBGTCR
0x0023
DBGC2
ARM
TBF
R
reserved
W
R
W
0
6
0
TRIG
0
5
4
3
2
reserved
BDM
DBGBRK
reserved
0
0
0
SSF2
TSOURCE
0
TRANGE
0
1
Bit 0
COMRV
SSF1
SSF0
TRCMOD
TALIGN
CDCM
ABCM
0
Figure 6-2. Quick Reference to S12XDBG Registers
S12XS Family Reference Manual, Rev. 1.10
196
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Address
Name
Bit 7
Bit 15
6
Bit 14
5
Bit 13
4
Bit 12
3
Bit 11
2
Bit 10
1
Bit 9
Bit 0
Bit 8
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
SC3
SC2
SC1
SC0
0x0024
DBGTBH
R
W
0x0025
DBGTBL
R
W
Bit 7
0x0026
DBGCNT
R
W
0
0x0027
DBGSCRX
0
0
0
0
0x0027
DBGMFR
R
W
R
W
0
0
0
0
MC3
MC2
MC1
MC0
NDB
TAG
BRK
RW
RWE
reserved
COMPE
SZ
TAG
BRK
RW
RWE
reserved
COMPE
Bit 22
21
20
19
18
17
Bit 16
0x00281
0x00282
DBGXCTL R
(COMPA/C) W
DBGXCTL R
(COMPB/D) W
0
SZE
0
CNT
0x0029
DBGXAH
R
W
0x002A
DBGXAM
R
W
Bit 15
14
13
12
11
10
9
Bit 8
0x002B
DBGXAL
R
W
Bit 7
6
5
4
3
2
1
Bit 0
0x002C
DBGXDH
R
W
Bit 15
14
13
12
11
10
9
Bit 8
0x002D
DBGXDL
R
W
Bit 7
6
5
4
3
2
1
Bit 0
0x002E
DBGXDHM
R
W
Bit 15
14
13
12
11
10
9
Bit 8
1
Bit 0
R
Bit 7
6
5
4
3
2
W
1 This represents the contents if the Comparator A or C control register is blended into this address.
2 This represents the contents if the Comparator B or D control register is blended into this address
0x002F
DBGXDLM
Figure 6-2. Quick Reference to S12XDBG Registers
6.3.2
Register Descriptions
This section consists of the S12XDBG control and trace buffer register descriptions in address order. Each
comparator has a bank of registers that are visible through an 8-byte window between 0x0028 and 0x002F
in the S12XDBG module register address map. When ARM is set in DBGC1, the only bits in the
S12XDBG module registers that can be written are ARM, TRIG, and COMRV[1:0]
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
197
S12X Debug (S12XDBGV3) Module
6.3.2.1
Debug Control Register 1 (DBGC1)
Address: 0x0020
7
R
W
Reset
6
ARM
0
0
TRIG
0
5
4
3
2
reserved
BDM
DBGBRK
reserved
0
0
0
0
1
0
COMRV
0
0
Figure 6-3. Debug Control Register (DBGC1)
Read: Anytime
Write: Bits 7, 1, 0 anytime
Bit 6 can be written anytime but always reads back as 0.
Bits 5:2 anytime S12XDBG is not armed.
NOTE
If a write access to DBGC1 with the ARM bit position set occurs
simultaneously to a hardware disarm from an internal trigger event, then the
ARM bit is cleared due to the hardware disarm.
NOTE
When disarming the S12XDBG by clearing ARM with software, the
contents of bits[5:2] are not affected by the write, since up until the write
operation, ARM = 1 preventing these bits from being written. These bits
must be cleared using a second write if required.
Table 6-4. DBGC1 Field Descriptions
Field
Description
7
ARM
Arm Bit — The ARM bit controls whether the S12XDBG module is armed. This bit can be set and cleared by
user software and is automatically cleared on completion of a tracing session, or if a breakpoint is generated with
tracing not enabled. On setting this bit the state sequencer enters State1.
0 Debugger disarmed
1 Debugger armed
6
TRIG
Immediate Trigger Request Bit — This bit when written to 1 requests an immediate trigger independent of
comparator signal status. When tracing is complete a forced breakpoint may be generated depending upon
DBGBRK and BDM bit settings. This bit always reads back a 0. Writing a 0 to this bit has no effect. If TSOURCE
is clear no tracing is carried out. If tracing has already commenced using BEGIN- or MID trigger alignment, it
continues until the end of the tracing session as defined by the TALIGN bit settings, thus TRIG has no affect. In
secure mode tracing is disabled and writing to this bit has no effect.
0 Do not trigger until the state sequencer enters the Final State.
1 Trigger immediately .
5
reserved
4
BDM
This bit is reserved, setting it has no meaning or effect.
Background Debug Mode Enable — This bit determines if an S12X breakpoint causes the system to enter
Background Debug Mode (BDM) or initiate a Software Interrupt (SWI). If this bit is set but the BDM is not enabled
by the ENBDM bit in the BDM module, then breakpoints default to SWI.
0 Breakpoint to Software Interrupt if BDM inactive. Otherwise no breakpoint.
1 Breakpoint to BDM, if BDM enabled. Otherwise breakpoint to SWI
S12XS Family Reference Manual, Rev. 1.10
198
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Table 6-4. DBGC1 Field Descriptions (continued)
Field
Description
3
DBGBRK
S12XDBG Breakpoint Enable Bit — The DBGBRK bit controls whether the debugger will request a breakpoint
to S12XCPU upon reaching the state sequencer Final State. If tracing is enabled, the breakpoint is generated
on completion of the tracing session. If tracing is not enabled, the breakpoint is generated immediately. Please
refer to Section 6.4.7 for further details.
0 No breakpoint on trigger.
1 Breakpoint on trigger
1–0
COMRV
Comparator Register Visibility Bits — These bits determine which bank of comparator register is visible in the
8-byte window of the S12XDBG module address map, located between 0x0028 to 0x002F. Furthermore these
bits determine which register is visible at the address 0x0027. See Table 6-5.
Table 6-5. COMRV Encoding
6.3.2.2
COMRV
Visible Comparator
Visible Register at 0x0027
00
Comparator A
DBGSCR1
01
Comparator B
DBGSCR2
10
Comparator C
DBGSCR3
11
Comparator D
DBGMFR
Debug Status Register (DBGSR)
Address: 0x0021
R
7
6
5
4
3
2
1
0
TBF
0
0
0
0
SSF2
SSF1
SSF0
—
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
POR
= Unimplemented or Reserved
Figure 6-4. Debug Status Register (DBGSR)
Read: Anytime
Write: Never
Table 6-6. DBGSR Field Descriptions
Field
Description
7
TBF
Trace Buffer Full — The TBF bit indicates that the trace buffer has stored 64 or more lines of data since it was
last armed. If this bit is set, then all 64 lines will be valid data, regardless of the value of DBGCNT bits CNT[6:0].
The TBF bit is cleared when ARM in DBGC1 is written to a one. The TBF is cleared by the power on reset
initialization. Other system generated resets have no affect on this bit
2–0
SSF[2:0]
State Sequencer Flag Bits — The SSF bits indicate in which state the State Sequencer is currently in. During
a debug session on each transition to a new state these bits are updated. If the debug session is ended by
software clearing the ARM bit, then these bits retain their value to reflect the last state of the state sequencer
before disarming. If a debug session is ended by an internal trigger, then the state sequencer returns to state0
and these bits are cleared to indicate that state0 was entered during the session. On arming the module the state
sequencer enters state1 and these bits are forced to SSF[2:0] = 001. See Table 6-7.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
199
S12X Debug (S12XDBGV3) Module
Table 6-7. SSF[2:0] — State Sequence Flag Bit Encoding
6.3.2.3
SSF[2:0]
Current State
000
State0 (disarmed)
001
State1
010
State2
011
State3
100
Final State
101,110,111
Reserved
Debug Trace Control Register (DBGTCR)
Address: 0x0022
R
W
Reset
7
6
reserved
TSOURCE
0
0
5
4
3
TRANGE
0
2
1
TRCMOD
0
0
0
TALIGN
0
0
0
Figure 6-5. Debug Trace Control Register (DBGTCR)
Read: Anytime
Write: Bits 7:6 only when S12XDBG is neither secure nor armed.
Bits 5:0 anytime the module is disarmed.
WARNING
DBGTCR[7] is reserved. Setting this bit maps the tracing to an unimplemented bus, thus
preventing proper operation.
Table 6-8. DBGTCR Field Descriptions
Field
Description
6
TSOURCE
Trace Source Control Bits — The TSOURCE enables the tracing session. If the MCU system is secured, this
bit cannot be set and tracing is inhibited.
0 No tracing selected
1 Tracing selected
5–4
TRANGE
Trace Range Bits — The TRANGE bits allow filtering of trace information from a selected address range when
tracing from the CPU12X in Detail Mode. To use a comparator for range filtering, the corresponding COMPE
bits must remain cleared. If the COMPE bit is not clear then the comparator will also be used to generate state
sequence triggers. See Table 6-9.
3–2
TRCMOD
Trace Mode Bits — See Section 6.4.5.2 for detailed Trace Mode descriptions. In Normal Mode, change of flow
information is stored. In Loop1 Mode, change of flow information is stored but redundant entries into trace
memory are inhibited. In Detail Mode, address and data for all memory and register accesses is stored. See
Table 6-10.
1–0
TALIGN
Trigger Align Bits — These bits control whether the trigger is aligned to the beginning, end or the middle of a
tracing session. See Table 6-11.
S12XS Family Reference Manual, Rev. 1.10
200
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Table 6-9. TRANGE Trace Range Encoding
TRANGE
Tracing Range
00
Trace from all addresses (No filter)
01
Trace only in address range from $00000 to Comparator D
10
Trace only in address range from Comparator C to $7FFFFF
11
Trace only in range from Comparator C to Comparator D
Table 6-10. TRCMOD Trace Mode Bit Encoding
TRCMOD
Description
00
Normal
01
Loop1
10
Detail
11
Pure PC
Table 6-11. TALIGN Trace Alignment Encoding
6.3.2.4
TALIGN
Description
00
Trigger at end of stored data
01
Trigger before storing data
10
Trace buffer entries before and after trigger
11
Reserved
Debug Control Register2 (DBGC2)
Address: 0x0023
R
7
6
5
4
0
0
0
0
0
0
0
3
0
1
CDCM
W
Reset
2
0
0
ABCM
0
0
0
= Unimplemented or Reserved
Figure 6-6. Debug Control Register2 (DBGC2)
Read: Anytime
Write: Anytime the module is disarmed.
This register configures the comparators for range matching.
Table 6-12. DBGC2 Field Descriptions
Field
Description
3–2
CDCM[1:0]
C and D Comparator Match Control — These bits determine the C and D comparator match mapping as
described in Table 6-13.
1–0
ABCM[1:0]
A and B Comparator Match Control — These bits determine the A and B comparator match mapping as
described in Table 6-14.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
201
S12X Debug (S12XDBGV3) Module
Table 6-13. CDCM Encoding
CDCM
Description
00
Match2 mapped to comparator C match....... Match3 mapped to comparator D match.
01
Match2 mapped to comparator C/D inside range....... Match3 disabled.
10
Match2 mapped to comparator C/D outside range....... Match3 disabled.
11
Reserved1
1 Currently defaults to Match2 mapped to comparator C : Match3 mapped to comparator D
Table 6-14. ABCM Encoding
ABCM
Description
00
Match0 mapped to comparator A match....... Match1 mapped to comparator B match.
01
Match 0 mapped to comparator A/B inside range....... Match1 disabled.
10
Match 0 mapped to comparator A/B outside range....... Match1 disabled.
11
Reserved1
Currently
defaults
to
Match0
mapped
to
comparator
A
:
Match1 mapped to comparator B
1
6.3.2.5
Debug Trace Buffer Register (DBGTBH:DBGTBL)
Address: 0x0024, 0x0025
15
R
W
14
13
12
11
10
9
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9
8
7
6
5
4
3
2
1
0
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
POR
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Other
Resets
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Figure 6-7. Debug Trace Buffer Register (DBGTB)
Read: Only when unlocked AND not secured AND not armed AND with the TSOURCE bit set.
Write: Aligned word writes when disarmed unlock the trace buffer for reading but do not affect trace buffer
contents.
Table 6-15. DBGTB Field Descriptions
Field
Description
15–0
Bit[15:0]
Trace Buffer Data Bits — The Trace Buffer Register is a window through which the 64-bit wide data lines of the
Trace Buffer may be read 16 bits at a time. Each valid read of DBGTB increments an internal trace buffer pointer
which points to the next address to be read. When the ARM bit is written to 1 the trace buffer is locked to prevent
reading. The trace buffer can only be unlocked for reading by writing to DBGTB with an aligned word write when
the module is disarmed. The DBGTB register can be read only as an aligned word, any byte reads or misaligned
access of these registers will return 0 and will not cause the trace buffer pointer to increment to the next trace
buffer address. The same is true for word reads while the debugger is armed. The POR state is undefined Other
resets do not affect the trace buffer contents. .
S12XS Family Reference Manual, Rev. 1.10
202
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
6.3.2.6
Debug Count Register (DBGCNT)
Address: 0x0026
7
R
6
5
4
0
3
2
1
0
—
0
—
0
—
0
CNT
W
Reset
POR
0
0
—
0
—
0
—
0
—
0
= Unimplemented or Reserved
Figure 6-8. Debug Count Register (DBGCNT)
Read: Anytime
Write: Never
Table 6-16. DBGCNT Field Descriptions
Field
Description
6–0
CNT[6:0]
Count Value — The CNT bits [6:0] indicate the number of valid data 64-bit data lines stored in the Trace Buffer.
Table 6-17 shows the correlation between the CNT bits and the number of valid data lines in the Trace Buffer.
When the CNT rolls over to zero, the TBF bit in DBGSR is set and incrementing of CNT will continue in endtrigger or mid-trigger mode. The DBGCNT register is cleared when ARM in DBGC1 is written to a one. The
DBGCNT register is cleared by power-on-reset initialization but is not cleared by other system resets. Thus
should a reset occur during a debug session, the DBGCNT register still indicates after the reset, the number of
valid trace buffer entries stored before the reset occurred. The DBGCNT register is not decremented when
reading from the trace buffer.
Table 6-17. CNT Decoding Table
6.3.2.7
TBF (DBGSR)
CNT[6:0]
Description
0
0000000
No data valid
0
0000001
32 bits of one line valid
0
0000010
0000100
0000110
..
1111100
1 line valid
2 lines valid
3 lines valid
..
62 lines valid
0
1111110
63 lines valid
1
0000000
64 lines valid; if using Begin trigger alignment,
ARM bit will be cleared and the tracing session ends.
1
0000010
..
..
1111110
64 lines valid,
oldest data has been overwritten by most recent data
Debug State Control Registers
There is a dedicated control register for each of the state sequencer states 1 to 3 that determines if
transitions from that state are allowed, depending upon comparator matches or tag hits, and defines the
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
203
S12X Debug (S12XDBGV3) Module
next state for the state sequencer following a match. The three debug state control registers are located at
the same address in the register address map (0x0027). Each register can be accessed using the COMRV
bits in DBGC1 to blend in the required register. The COMRV = 11 value blends in the match flag register
(DBGMFR).
Table 6-18. State Control Register Access Encoding
6.3.2.7.1
COMRV
Visible State Control Register
00
DBGSCR1
01
DBGSCR2
10
DBGSCR3
11
DBGMFR
Debug State Control Register 1 (DBGSCR1)
Address: 0x0027
R
7
6
5
4
0
0
0
0
0
0
0
W
Reset
0
3
2
1
0
SC3
SC2
SC1
SC0
0
0
0
0
= Unimplemented or Reserved
Figure 6-9. Debug State Control Register 1 (DBGSCR1)
Read: If COMRV[1:0] = 00
Write: If COMRV[1:0] = 00 and S12XDBG is not armed.
This register is visible at 0x0027 only with COMRV[1:0] = 00. The state control register 1 selects the
targeted next state whilst in State1. The matches refer to the match channels of the comparator match
control logic as depicted in Figure 6-1 and described in Section 6.3.2.8.1”. Comparators must be enabled
by setting the comparator enable bit in the associated DBGXCTL control register.
Table 6-19. DBGSCR1 Field Descriptions
Field
3–0
SC[3:0]
Description
These bits select the targeted next state whilst in State1, based upon the match event.
Table 6-20. State1 Sequencer Next State Selection
SC[3:0]
0000
0001
0010
0011
0100
0101
0110
Description
Any match triggers to state2
Any match triggers to state3
Any match triggers to Final State
Match2 triggers to State2....... Other matches have no effect
Match2 triggers to State3....... Other matches have no effect
Match2 triggers to Final State....... Other matches have no effect
Match0 triggers to State2....... Match1 triggers to State3....... Other matches have no effect
S12XS Family Reference Manual, Rev. 1.10
204
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Table 6-20. State1 Sequencer Next State Selection (continued)
SC[3:0]
0111
1000
1001
1010
1011
1100
1101
1110
1111
Description
Match1 triggers to State3....... Match0 triggers Final State....... Other matches have no effect
Match0 triggers to State2....... Match2 triggers to State3....... Other matches have no effect
Match2 triggers to State3....... Match0 triggers Final State....... Other matches have no effect
Match1 triggers to State2....... Match3 triggers to State3....... Other matches have no effect
Match3 triggers to State3....... Match1 triggers to Final State....... Other matches have no effect
Match3 has no effect....... All other matches (M0,M1,M2) trigger to State2
Reserved. (No match triggers state sequencer transition)
Reserved. (No match triggers state sequencer transition)
Reserved. (No match triggers state sequencer transition)
The trigger priorities described in Table 6-39 dictate that in the case of simultaneous matches, the match
on the lower channel number (0,1,2,3) has priority. The SC[3:0] encoding ensures that a match leading to
final state has priority over all other matches.
6.3.2.7.2
Debug State Control Register 2 (DBGSCR2)
Address: 0x0027
R
7
6
5
4
0
0
0
0
0
0
0
W
Reset
0
3
2
1
0
SC3
SC2
SC1
SC0
0
0
0
0
= Unimplemented or Reserved
Figure 6-10. Debug State Control Register 2 (DBGSCR2)
Read: If COMRV[1:0] = 01
Write: If COMRV[1:0] = 01 and S12XDBG is not armed.
This register is visible at 0x0027 only with COMRV[1:0] = 01. The state control register 2 selects the
targeted next state whilst in State2. The matches refer to the match channels of the comparator match
control logic as depicted in Figure 6-1 and described in Section 6.3.2.8.1”. Comparators must be enabled
by setting the comparator enable bit in the associated DBGXCTL control register.
Table 6-21. DBGSCR2 Field Descriptions
Field
3–0
SC[3:0]
Description
These bits select the targeted next state whilst in State2, based upon the match event.
Table 6-22. State2 —Sequencer Next State Selection
SC[3:0]
0000
0001
0010
0011
0100
Description
Any match triggers to state1
Any match triggers to state3
Any match triggers to Final State
Match3 triggers to State1....... Other matches have no effect
Match3 triggers to State3....... Other matches have no effect
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
205
S12X Debug (S12XDBGV3) Module
Table 6-22. State2 —Sequencer Next State Selection (continued)
SC[3:0]
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Description
Match3 triggers to Final State....... Other matches have no effect
Match0 triggers to State1....... Match1 triggers to State3....... Other matches have no effect
Match1 triggers to State3....... Match0 triggers Final State....... Other matches have no effect
Match0 triggers to State1....... Match2 triggers to State3....... Other matches have no effect
Match2 triggers to State3....... Match0 triggers Final State....... Other matches have no effect
Match1 triggers to State1....... Match3 triggers to State3....... Other matches have no effect
Match3 triggers to State3....... Match1 triggers Final State....... Other matches have no effect
Match2 triggers to State1..... Match3 trigger to Final State
Match2 has no affect, all other matches (M0,M1,M3) trigger to Final State
Reserved. (No match triggers state sequencer transition)
Reserved. (No match triggers state sequencer transition)
The trigger priorities described in Table 6-39 dictate that in the case of simultaneous matches, the match
on the lower channel number (0,1,2,3) has priority. The SC[3:0] encoding ensures that a match leading to
final state has priority over all other matches.
6.3.2.7.3
Debug State Control Register 3 (DBGSCR3)
Address: 0x0027
R
7
6
5
4
0
0
0
0
0
0
0
W
Reset
0
3
2
1
0
SC3
SC2
SC1
SC0
0
0
0
0
= Unimplemented or Reserved
Figure 6-11. Debug State Control Register 3 (DBGSCR3)
Read: If COMRV[1:0] = 10
Write: If COMRV[1:0] = 10 and S12XDBG is not armed.
This register is visible at 0x0027 only with COMRV[1:0] = 10. The state control register three selects the
targeted next state whilst in State3. The matches refer to the match channels of the comparator match
control logic as depicted in Figure 6-1 and described in Section 6.3.2.8.1”. Comparators must be enabled
by setting the comparator enable bit in the associated DBGXCTL control register.
Table 6-23. DBGSCR3 Field Descriptions
Field
3–0
SC[3:0]
Description
These bits select the targeted next state whilst in State3, based upon the match event.
Table 6-24. State3 — Sequencer Next State Selection
SC[3:0]
0000
0001
Description
Any match triggers to state1
Any match triggers to state2
S12XS Family Reference Manual, Rev. 1.10
206
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Table 6-24. State3 — Sequencer Next State Selection
SC[3:0]
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Description
Any match triggers to Final State
Match0 triggers to State1....... Other matches have no effect
Match0 triggers to State2....... Other matches have no effect
Match0 triggers to Final State.......Match1 triggers to State1...Other matches have no effect
Match1 triggers to State1....... Other matches have no effect
Match1 triggers to State2....... Other matches have no effect
Match1 triggers to Final State....... Other matches have no effect
Match2 triggers to State2....... Match0 triggers to Final State....... Other matches have no effect
Match1 triggers to State1....... Match3 triggers to State2....... Other matches have no effect
Match3 triggers to State2....... Match1 triggers to Final State....... Other matches have no effect
Match2 triggers to Final State....... Other matches have no effect
Match3 triggers to Final State....... Other matches have no effect
Reserved. (No match triggers state sequencer transition)
Reserved. (No match triggers state sequencer transition)
The trigger priorities described in Table 6-39 dictate that in the case of simultaneous matches, the match
on the lower channel number (0,1,2,3) has priority. The SC[3:0] encoding ensures that a match leading to
final state has priority over all other matches.
6.3.2.7.4
Debug Match Flag Register (DBGMFR)
Address: 0x0027
R
7
6
5
4
3
2
1
0
0
0
0
0
MC3
MC2
MC1
MC0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 6-12. Debug Match Flag Register (DBGMFR)
Read: If COMRV[1:0] = 11
Write: Never
DBGMFR is visible at 0x0027 only with COMRV[1:0] = 11. It features four flag bits each mapped directly
to a channel. Should a match occur on the channel during the debug session, then the corresponding flag
is set and remains set until the next time the module is armed by writing to the ARM bit. Thus the contents
are retained after a debug session for evaluation purposes. These flags cannot be cleared by software, they
are cleared only when arming the module. A set flag does not inhibit the setting of other flags. Once a flag
is set, further triggers on the same channel have no affect.
6.3.2.8
Comparator Register Descriptions
Each comparator has a bank of registers that are visible through an 8-byte window in the S12XDBG
module register address map. Comparators A and C consist of 8 register bytes (3 address bus compare
registers, two data bus compare registers, two data bus mask registers and a control register).
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
207
S12X Debug (S12XDBGV3) Module
Comparators B and D consist of four register bytes (three address bus compare registers and a control
register).
Each set of comparator registers is accessible in the same 8-byte window of the register address map and
can be accessed using the COMRV bits in the DBGC1 register. If the Comparators B or D are accessed
through the 8-byte window, then only the address and control bytes are visible, the 4 bytes associated with
data bus and data bus masking read as zero and cannot be written. Furthermore the control registers for
comparators B and D differ from those of comparators A and C.
Table 6-25. Comparator Register Layout
0x0028
CONTROL
Read/Write
Comparators A,B,C,D
0x0029
ADDRESS HIGH
Read/Write
Comparators A,B,C,D
0x002A
ADDRESS MEDIUM
Read/Write
Comparators A,B,C,D
0x002B
ADDRESS LOW
Read/Write
Comparators A,B,C,D
0x002C
DATA HIGH COMPARATOR
Read/Write
Comparator A and C only
0x002D
DATA LOW COMPARATOR
Read/Write
Comparator A and C only
0x002E
DATA HIGH MASK
Read/Write
Comparator A and C only
0x002F
DATA LOW MASK
Read/Write
Comparator A and C only
6.3.2.8.1
Debug Comparator Control Register (DBGXCTL)
The contents of this register bits 7 and 6 differ depending upon which comparator registers are visible in
the 8-byte window of the DBG module register address map.
Address: 0x0028
7
R
0
W
Reset
0
6
5
4
3
2
1
0
NDB
TAG
BRK
RW
RWE
reserved
COMPE
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 6-13. Debug Comparator Control Register (Comparators A and C)
Address: 0x0028
R
W
Reset
7
6
5
4
3
2
1
0
SZE
SZ
TAG
BRK
RW
RWE
reserved
COMPE
0
0
0
0
0
0
0
0
Figure 6-14. Debug Comparator Control Register (Comparators B and D)
Read: Anytime. See Table 6-26 for visible register encoding.
Write: If DBG not armed. See Table 6-26 for visible register encoding.
WARNING
DBGXCTL[1] is reserved. Setting this bit maps the corresponding comparator to an
S12XS Family Reference Manual, Rev. 1.10
208
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
unimplemented bus, thus preventing proper operation.
The DBGC1_COMRV bits determine which comparator control, address, data and datamask registers are
visible in the 8-byte window from 0x0028 to 0x002F as shown in Section Table 6-26.
Table 6-26. Comparator Address Register Visibility
COMRV
Visible Comparator
00
DBGACTL, DBGAAH ,DBGAAM, DBGAAL, DBGADH, DBGADL, DBGADHM, DBGADLM
01
DBGBCTL, DBGBAH, DBGBAM, DBGBAL
10
DBGCCTL, DBGCAH, DBGCAM, DBGCAL, DBGCDH, DBGCDL, DBGCDHM, DBGCDLM
11
DBGDCTL, DBGDAH, DBGDAM, DBGDAL
Table 6-27. DBGXCTL Field Descriptions
Field
Description
7
SZE
(Comparators
B and D)
Size Comparator Enable Bit — The SZE bit controls whether access size comparison is enabled for the
associated comparator. This bit is ignored if the TAG bit in the same register is set.
0 Word/Byte access size is not used in comparison
1 Word/Byte access size is used in comparison
6
NDB
(Comparators
A and C
Not Data Bus — The NDB bit controls whether the match occurs when the data bus matches the comparator
register value or when the data bus differs from the register value. Furthermore data bus bits can be
individually masked using the comparator data mask registers. This bit is only available for comparators A
and C. This bit is ignored if the TAG bit in the same register is set. This bit position has an SZ functionality for
comparators B and D.
0 Match on data bus equivalence to comparator register contents
1 Match on data bus difference to comparator register contents
6
SZ
(Comparators
B and D)
Size Comparator Value Bit — The SZ bit selects either word or byte access size in comparison for the
associated comparator. This bit is ignored if the SZE bit is cleared or if the TAG bit in the same register is set.
This bit position has NDB functionality for comparators A and C
0 Word access size will be compared
1 Byte access size will be compared
5
TAG
Tag Select — This bit controls whether the comparator match will cause a trigger or tag the opcode at the
matched address. Tagged opcodes trigger only if they reach the execution stage of the instruction queue.
0 Trigger immediately on match
1 On match, tag the opcode. If the opcode is about to be executed a trigger is generated
4
BRK
Break — This bit controls whether a channel match terminates a debug session immediately, independent
of state sequencer state. To generate an immediate breakpoint the module breakpoints must be enabled
using DBGBRK.
0 The debug session termination is dependent upon the state sequencer and trigger conditions.
1 A match on this channel terminates the debug session immediately; breakpoints if active are generated,
tracing, if active, is terminated and the module disarmed.
3
RW
Read/Write Comparator Value Bit — The RW bit controls whether read or write is used in compare for the
associated comparator . The RW bit is not used if RWE = 0.
0 Write cycle will be matched
1 Read cycle will be matched
2
RWE
Read/Write Enable Bit — The RWE bit controls whether read or write comparison is enabled for the
associated comparator. This bit is not used for tagged operations.
0 Read/Write is not used in comparison
1 Read/Write is used in comparison
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
209
S12X Debug (S12XDBGV3) Module
Table 6-27. DBGXCTL Field Descriptions (continued)
Field
Description
0
COMPE
Determines if comparator is enabled
0 The comparator is not enabled
1 The comparator is enabled for state sequence triggers or tag generation
Table 6-28 shows the effect for RWE and RW on the comparison conditions. These bits are not useful for
tagged operations since the trigger occurs based on the tagged opcode reaching the execution stage of the
instruction queue. Thus these bits are ignored if tagged triggering is selected.
Table 6-28. Read or Write Comparison Logic Table
6.3.2.8.2
RWE Bit
RW Bit
RW Signal
Comment
0
x
0
RW not used in comparison
0
x
1
RW not used in comparison
1
0
0
Write
1
0
1
No match
1
1
0
No match
1
1
1
Read
Debug Comparator Address High Register (DBGXAH)
Address: 0x0029
7
R
0
W
Reset
0
6
5
4
3
2
1
0
Bit 22
Bit 21
Bit 20
Bit 19
Bit 18
Bit 17
Bit 16
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 6-15. Debug Comparator Address High Register (DBGXAH)
Read: Anytime. See Table 6-26 for visible register encoding.
Write: If DBG not armed. See Table 6-26 for visible register encoding.
Table 6-29. DBGXAH Field Descriptions
Field
Description
6–0
Bit[22:16]
Comparator Address High Compare Bits — The Comparator address high compare bits control whether the
selected comparator will compare the address bus bits [22:16] to a logic one or logic zero. .
0 Compare corresponding address bit to a logic zero
1 Compare corresponding address bit to a logic one
S12XS Family Reference Manual, Rev. 1.10
210
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
6.3.2.8.3
Debug Comparator Address Mid Register (DBGXAM)
Address: 0x002A
R
W
Reset
7
6
5
4
3
2
1
0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
0
0
0
0
0
0
0
0
Figure 6-16. Debug Comparator Address Mid Register (DBGXAM)
Read: Anytime. See Table 6-26 for visible register encoding.
Write: If DBG not armed. See Table 6-26 for visible register encoding.
Table 6-30. DBGXAM Field Descriptions
Field
7–0
Bit[15:8]
Description
Comparator Address Mid Compare Bits— The Comparator address mid compare bits control whether the
selected comparator will compare the address bus bits [15:8] to a logic one or logic zero.
0 Compare corresponding address bit to a logic zero
1 Compare corresponding address bit to a logic one
6.3.2.8.4
Debug Comparator Address Low Register (DBGXAL)
Address: 0x002B
R
W
Reset
7
6
5
4
3
2
1
0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
0
0
0
0
0
0
Figure 6-17. Debug Comparator Address Low Register (DBGXAL)
Read: Anytime. See Table 6-26 for visible register encoding.
Write: If DBG not armed. See Table 6-26 for visible register encoding.
Table 6-31. DBGXAL Field Descriptions
Field
7–0
Bits[7:0]
Description
Comparator Address Low Compare Bits — The Comparator address low compare bits control whether the
selected comparator will compare the address bus bits [7:0] to a logic one or logic zero.
0 Compare corresponding address bit to a logic zero
1 Compare corresponding address bit to a logic one
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
211
S12X Debug (S12XDBGV3) Module
6.3.2.8.5
Debug Comparator Data High Register (DBGXDH)
Address: 0x002C
R
W
Reset
7
6
5
4
3
2
1
0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
0
0
0
0
0
0
0
0
Figure 6-18. Debug Comparator Data High Register (DBGXDH)
Read: Anytime. See Table 6-26 for visible register encoding.
Write: If DBG not armed. See Table 6-26 for visible register encoding.
Table 6-32. DBGXAH Field Descriptions
Field
Description
7–0
Bits[15:8]
Comparator Data High Compare Bits — The Comparator data high compare bits control whether the selected
comparator compares the data bus bits [15:8] to a logic one or logic zero. The comparator data compare bits are
only used in comparison if the corresponding data mask bit is logic 1. This register is available only for
comparators A and C.
0 Compare corresponding data bit to a logic zero
1 Compare corresponding data bit to a logic one
6.3.2.8.6
Debug Comparator Data Low Register (DBGXDL)
Address: 0x002D
R
W
Reset
7
6
5
4
3
2
1
0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
0
0
0
0
0
0
Figure 6-19. Debug Comparator Data Low Register (DBGXDL)
Read: Anytime. See Table 6-26 for visible register encoding.
Write: If DBG not armed. See Table 6-26 for visible register encoding.
Table 6-33. DBGXDL Field Descriptions
Field
Description
7–0
Bits[7:0]
Comparator Data Low Compare Bits — The Comparator data low compare bits control whether the selected
comparator compares the data bus bits [7:0] to a logic one or logic zero. The comparator data compare bits are
only used in comparison if the corresponding data mask bit is logic 1. This register is available only for
comparators A and C.
0 Compare corresponding data bit to a logic zero
1 Compare corresponding data bit to a logic one
S12XS Family Reference Manual, Rev. 1.10
212
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
6.3.2.8.7
Debug Comparator Data High Mask Register (DBGXDHM)
Address: 0x002E
R
W
Reset
7
6
5
4
3
2
1
0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
0
0
0
0
0
0
0
0
Figure 6-20. Debug Comparator Data High Mask Register (DBGXDHM)
Read: Anytime. See Table 6-26 for visible register encoding.
Write: If DBG not armed. See Table 6-26 for visible register encoding.
Table 6-34. DBGXDHM Field Descriptions
Field
Description
7–0
Bits[15:8]
Comparator Data High Mask Bits — The Comparator data high mask bits control whether the selected
comparator compares the data bus bits [15:8] to the corresponding comparator data compare bits. This register
is available only for comparators A and C.
0 Do not compare corresponding data bit
1 Compare corresponding data bit
6.3.2.8.8
Debug Comparator Data Low Mask Register (DBGXDLM)
Address: 0x002F
R
W
Reset
7
6
5
4
3
2
1
0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
0
0
0
0
0
0
Figure 6-21. Debug Comparator Data Low Mask Register (DBGXDLM)
Read: Anytime. See Table 6-26 for visible register encoding.
Write: If DBG not armed. See Table 6-26 for visible register encoding.
Table 6-35. DBGXDLM Field Descriptions
Field
Description
7–0
Bits[7:0]
Comparator Data Low Mask Bits — The Comparator data low mask bits control whether the selected
comparator compares the data bus bits [7:0] to the corresponding comparator data compare bits. This register
is available only for comparators A and C.
0 Do not compare corresponding data bit
1 Compare corresponding data bit
6.4
Functional Description
This section provides a complete functional description of the S12XDBG module. If the part is in secure
mode, the S12XDBG module can generate breakpoints but tracing is not possible.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
213
S12X Debug (S12XDBGV3) Module
6.4.1
S12XDBG Operation
Arming the S12XDBG module by setting ARM in DBGC1 allows triggering, and storing of data in the
trace buffer and can be used to cause breakpoints to the CPU12X . The DBG module is made up of four
main blocks, the comparators, control logic, the state sequencer, and the trace buffer.
The comparators monitor the bus activity of the CPU12X . Comparators can be configured to monitor
address and databus. Comparators can also be configured to mask out individual data bus bits during a
compare and to use R/W and word/byte access qualification in the comparison. When a match with a
comparator register value occurs the associated control logic can trigger the state sequencer to another state
(see Figure 6-22). Either forced or tagged triggers are possible. Using a forced trigger, the trigger is
generated immediately on a comparator match. Using a tagged trigger, at a comparator match, the
instruction opcode is tagged and only if the instruction reaches the execution stage of the instruction queue
is a trigger generated. In the case of a transition to Final State, bus tracing is triggered and/or a breakpoint
can be generated.
Independent of the state sequencer, a breakpoint can be triggered by writing to the TRIG bit in the DBGC1
control register.
The trace buffer is visible through a 2-byte window in the register address map and can be read out using
standard 16-bit word reads.
6.4.2
Comparator Modes
The S12XDBG contains four comparators, A, B, C, and D. Each comparator compares the selected address
bus with the address stored in DBGXAH, DBGXAM, and DBGXAL. Furthermore, comparators A and C
also compare the data buses to the data stored in DBGXDH, DBGXDL and allow masking of individual
data bus bits.
S12X comparator matches are disabled in BDM and during BDM accesses.
The comparator match control logic configures comparators to monitor the buses for an exact address or
an address range. The comparator configuration is controlled by the control register contents and the range
control by the DBGC2 contents.
On a match a trigger can initiate a transition to another state sequencer state (see Section 6.4.3”). The
comparator control register also allows the type of access to be included in the comparison through the use
of the RWE, RW, SZE, and SZ bits. The RWE bit controls whether read or write comparison is enabled
for the associated comparator and the RW bit selects either a read or write access for a valid match.
Similarly the SZE and SZ bits allows the size of access (word or byte) to be considered in the compare.
Only comparators B and D feature SZE and SZ.
The TAG bit in each comparator control register is used to determine the triggering condition. By setting
TAG, the comparator will qualify a match with the output of opcode tracking logic and a trigger occurs
before the tagged instruction executes (tagged-type trigger). Whilst tagging, the RW, RWE, SZE, and SZ
bits are ignored and the comparator register must be loaded with the exact opcode address.
If the TAG bit is clear (forced type trigger) a comparator match is generated when the selected address
appears on the system address bus. If the selected address is an opcode address, the match is generated
S12XS Family Reference Manual, Rev. 1.10
214
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
when the opcode is fetched from the memory. This precedes the instruction execution by an indefinite
number of cycles due to instruction pipe lining. For a comparator match of an opcode at an odd address
when TAG = 0, the corresponding even address must be contained in the comparator register. Thus for an
opcode at odd address (n), the comparator register must contain address (n–1).
Once a successful comparator match has occurred, the condition that caused the original match is not
verified again on subsequent matches. Thus if a particular data value is verified at a given address, this
address may not still contain that data value when a subsequent match occurs.
Comparators C and D can also be used to select an address range to trace from. This is determined by the
TRANGE bits in the DBGTCR register. The TRANGE encoding is shown in Table 6-9. If the TRANGE
bits select a range definition using comparator D, then comparator D is configured for trace range
definition and cannot be used for address bus comparisons. Similarly if the TRANGE bits select a range
definition using comparator C, then comparator C is configured for trace range definition and cannot be
used for address bus comparisons.
Match[0, 1, 2, 3] map directly to Comparators[A, B, C, D] respectively, except in range modes (see
Section 6.3.2.4”). Comparator priority rules are described in the trigger priority section (Section 6.4.3.4”).
6.4.2.1
Exact Address Comparator Match (Comparators A and C)
With range comparisons disabled, the match condition is an exact equivalence of address/data bus with the
value stored in the comparator address/data registers. Further qualification of the type of access (R/W,
word/byte) is possible.
Comparators A and C do not feature SZE or SZ control bits, thus the access size is not compared. Table 637 lists access considerations without data bus compare. Table 6-36 lists access considerations with data
bus comparison. To compare byte accesses DBGxDH must be loaded with the data byte, the low byte must
be masked out using the DBGxDLM mask register. On word accesses the data byte of the lower address
is mapped to DBGxDH.
Table 6-36. Comparator A and C Data Bus Considerations
Access
Address
DBGxDH
DBGxDL
DBGxDHM
DBGxDLM
Example Valid Match
Word
ADDR[n]
Data[n]
Data[n+1]
$FF
$FF
MOVW #$WORD ADDR[n]
config1
Byte
ADDR[n]
Data[n]
x
$FF
$00
MOVB #$BYTE ADDR[n]
config2
Word
ADDR[n]
Data[n]
x
$FF
$00
MOVW #$WORD ADDR[n]
config2
Word
ADDR[n]
x
Data[n+1]
$00
$FF
MOVW #$WORD ADDR[n]
config3
Code may contain various access forms of the same address, i.e. a word access of ADDR[n] or byte access
of ADDR[n+1] both access n+1. At a word access of ADDR[n], address ADDR[n+1] does not appear on
the address bus and so cannot cause a comparator match if the comparator contains ADDR[n]. Thus it is
not possible to monitor all data accesses of ADDR[n+1] with one comparator.
To detect an access of ADDR[n+1] through a word access of ADDR[n] the comparator can be configured
to ADDR[n], DBGxDL is loaded with the data pattern and DBGxDHM is cleared so only the data[n+1] is
compared on accesses of ADDR[n].
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
215
S12X Debug (S12XDBGV3) Module
NOTE
Using this configuration, a byte access of ADDR[n] can cause a comparator match if the databus low byte
by chance contains the same value as ADDR[n+1] because the databus comparator does not feature access
size comparison and uses the mask as a “don’t care” function. Thus masked bits do not prevent a match.
Comparators A and C feature an NDB control bit to determine if a match occurs when the data bus differs
to comparator register contents or when the data bus is equivalent to the comparator register contents.
6.4.2.2
Exact Address Comparator Match (Comparators B and D)
Comparators B and D feature SZ and SZE control bits. If SZE is clear, then the comparator address match
qualification functions the same as for comparators A and C.
If the SZE bit is set the access size (word or byte) is compared with the SZ bit value such that only the
specified type of access causes a match. Thus if configured for a byte access of a particular address, a word
access covering the same address does not lead to match.
Table 6-37. Comparator Access Size Considerations
Comparator
Address
SZE
SZ8
Condition For Valid Match
Comparators
A and C
ADDR[n]
—
—
Word and byte accesses of ADDR[n]1
MOVB #$BYTE ADDR[n]
MOVW #$WORD ADDR[n]
Comparators
B and D
ADDR[n]
0
X
Word and byte accesses of ADDR[n]1
MOVB #$BYTE ADDR[n]
MOVW #$WORD ADDR[n]
Comparators
B and D
ADDR[n]
1
0
Word accesses of ADDR[n]1
MOVW #$WORD ADDR[n]
Comparators
ADDR[n]
1
1
Byte accesses of ADDR[n]
B and D
MOVB #$BYTE ADDR[n]
A
word
access
of
ADDR[n-1]
also
accesses
ADDR[n]
but
does
not
generate
a match.
1
The comparator address register must contain the exact address used in the code.
6.4.2.3
Data Bus Comparison NDB Dependency
Comparators A and C each feature an NDB control bit, which allows data bus comparators to be configured
to either trigger on equivalence or trigger on difference. This allows monitoring of a difference in the
contents of an address location from an expected value.
When matching on an equivalence (NDB=0), each individual data bus bit position can be masked out by
clearing the corresponding mask bit (DBGxDHM/DBGxDLM), so that it is ignored in the comparison. A
match occurs when all data bus bits with corresponding mask bits set are equivalent. If all mask register
bits are clear, then a match is based on the address bus only, the data bus is ignored.
When matching on a difference, mask bits can be cleared to ignore bit positions. A match occurs when any
data bus bit with corresponding mask bit set is different. Clearing all mask bits, causes all bits to be ignored
and prevents a match because no difference can be detected. In this case address bus equivalence does not
cause a match.
S12XS Family Reference Manual, Rev. 1.10
216
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Table 6-38. NDB and MASK bit dependency
6.4.2.4
NDB
DBGxDHM[n] /
DBGxDLM[n]
Comment
0
0
Do not compare data bus bit.
0
1
Compare data bus bit. Match on equivalence.
1
0
Do not compare data bus bit.
1
1
Compare data bus bit. Match on difference.
Range Comparisons
When using the AB comparator pair for a range comparison, the data bus can also be used for qualification
by using the comparator A data and data mask registers. Furthermore the DBGACTL RW and RWE bits
can be used to qualify the range comparison on either a read or a write access. The corresponding
DBGBCTL bits are ignored. Similarly when using the CD comparator pair for a range comparison, the
data bus can also be used for qualification by using the comparator C data and data mask registers.
Furthermore the DBGCCTL RW and RWE bits can be used to qualify the range comparison on either a
read or a write access if tagging is not selected. The corresponding DBGDCTL bits are ignored. The SZE
and SZ control bits are ignored in range mode. The comparator A and C TAG bits are used to tag range
comparisons for the AB and CD ranges respectively. The comparator B and D TAG bits are ignored in
range modes. In order for a range comparison using comparators A and B, both COMPEA and COMPEB
must be set; to disable range comparisons both must be cleared. Similarly for a range CD comparison, both
COMPEC and COMPED must be set. The comparator A and C BRK bits are used for the AB and CD
ranges respectively, the comparator B and D BRK bits are ignored in range mode. When configured for
range comparisons and tagging, the ranges are accurate only to word boundaries.
6.4.2.4.1
Inside Range (CompAC_Addr ≤ address ≤ CompBD_Addr)
In the Inside Range comparator mode, either comparator pair A and B or comparator pair C and D can be
configured for range comparisons by the control register (DBGC2). The match condition requires that a
valid match for both comparators happens on the same bus cycle. A match condition on only one
comparator is not valid. An aligned word access which straddles the range boundary will cause a trigger
only if the aligned address is inside the range.
6.4.2.4.2
Outside Range (address < CompAC_Addr or address > CompBD_Addr)
In the Outside Range comparator mode, either comparator pair A and B or comparator pair C and D can
be configured for range comparisons. A single match condition on either of the comparators is recognized
as valid. An aligned word access which straddles the range boundary will cause a trigger only if the aligned
address is outside the range.
Outside range mode in combination with tagged triggers can be used to detect if the opcode fetches are
from an unexpected range. In forced trigger modes the outside range trigger would typically be activated
at any interrupt vector fetch or register access. This can be avoided by setting the upper or lower range limit
to $7FFFFF or $000000 respectively. Interrupt vector fetches do not cause taghits
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
217
S12X Debug (S12XDBGV3) Module
6.4.3
Trigger Modes
Trigger modes are used as qualifiers for a state sequencer change of state. The control logic determines the
trigger mode and provides a trigger to the state sequencer. The individual trigger modes are described in
the following sections.
6.4.3.1
Forced Trigger On Comparator Match
If a forced trigger comparator match occurs, the trigger immediately initiates a transition to the next state
sequencer state whereby the corresponding flags in DBGSR are set. The state control register for the
current state determines the next state for each trigger. Forced triggers are generated as soon as the
matching address appears on the address bus, which in the case of opcode fetches occurs several cycles
before the opcode execution. For this reason a forced trigger at an opcode address precedes a tagged trigger
at the same address by several cycles.
6.4.3.2
Trigger On Comparator Related Taghit
If a CPU12X taghit occurs, a transition to another state sequencer state is initiated and the corresponding
DBGSR flags are set. For a comparator related taghit to occur, the S12XDBG must first generate tags based
on comparator matches. When the tagged instruction reaches the execution stage of the instruction queue
a taghit is generated by the CPU12X. The state control register for the current state determines the next
state for each trigger.
6.4.3.3
TRIG Immediate Trigger
Independent of comparator matches it is possible to initiate a tracing session and/or breakpoint by writing
the TRIG bit in DBGC1 to a logic “1”. If configured for begin or mid aligned tracing, this triggers the state
sequencer into the Final State, if configured for end alignment, setting the TRIG bit disarms the module,
ending the session. If breakpoints are enabled, a forced breakpoint request is issued immediately (end
alignment) or when tracing has completed (begin or mid alignment).
6.4.3.4
Trigger Priorities
In case of simultaneous triggers, the priority is resolved according to Table 6-39. The lower priority trigger
is suppressed. It is thus possible to miss a lower priority trigger if it occurs simultaneously with a trigger
of a higher priority. The trigger priorities described in Table 6-39 dictate that in the case of simultaneous
matches, the match on the lower channel number (0,1,2,3) has priority. The SC[3:0] encoding ensures that
a match leading to final state has priority over all other matches in each state sequencer state. When
configured for range modes a simultaneous match of comparators A and C generates an active match0
whilst match2 is suppressed.
If a write access to DBGC1 with the ARM bit position set occurs simultaneously to a hardware disarm
from an internal trigger event, then the ARM bit is cleared due to the hardware disarm.
Table 6-39. Trigger Priorities
Priority
Source
Action
S12XS Family Reference Manual, Rev. 1.10
218
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Table 6-39. Trigger Priorities
Highest
Lowest
6.4.4
TRIG
Trigger immediately to final state (begin or mid aligned tracing enabled)
Trigger immediately to state 0 (end aligned or no tracing enabled)
Match0 (force or tag hit)
Trigger to next state as defined by state control registers
Match1 (force or tag hit)
Trigger to next state as defined by state control registers
Match2 (force or tag hit)
Trigger to next state as defined by state control registers
Match3 (force or tag hit)
Trigger to next state as defined by state control registers
State Sequence Control
ARM = 0
State 0
(Disarmed)
ARM = 1
State1
State2
ARM = 0
Session Complete
(Disarm)
Final State
State3
ARM = 0
Figure 6-22. State Sequencer Diagram
The state sequencer allows a defined sequence of events to provide a trigger point for tracing of data in the
trace buffer. Once the S12XDBG module has been armed by setting the ARM bit in the DBGC1 register,
then state1 of the state sequencer is entered. Further transitions between the states are then controlled by
the state control registers and depend upon a selected trigger mode condition being met. From Final State
the only permitted transition is back to the disarmed state0. Transition between any of the states 1 to 3 is
not restricted. Each transition updates the SSF[2:0] flags in DBGSR accordingly to indicate the current
state.
Alternatively by setting the TRIG bit in DBGSC1, the state machine can be triggered to state0 or Final
State depending on tracing alignment.
Independent of the state sequencer, each comparator channel can be individually configured to generate an
immediate breakpoint when a match occurs through the use of the BRK bits in the DBGxCTL registers.
Thus it is possible to generate an immediate breakpoint on selected channels, whilst a state sequencer
transition can be initiated by a match on other channels. If a debug session is ended by a trigger on a
channel with BRK = 1, the state sequencer transitions through Final State for a clock cycle to state0. This
is independent of tracing and breakpoint activity, thus with tracing and breakpoints disabled, the state
sequencer enters state0 and the debug module is disarmed.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
219
S12X Debug (S12XDBGV3) Module
6.4.4.1
Final State
On entering Final State a trigger may be issued to the trace buffer according to the trace position control
as defined by the TALIGN field (see Section 6.3.2.3”). If TSOURCE in the trace control register DBGTCR
is cleared then the trace buffer is disabled and the transition to Final State can only generate a breakpoint
request. In this case or upon completion of a tracing session when tracing is enabled, the ARM bit in the
DBGC1 register is cleared, returning the module to the disarmed state0. If tracing is enabled, a breakpoint
request can occur at the end of the tracing session. If neither tracing nor breakpoints are enabled then when
the final state is reached it returns automatically to state0 and the debug module is disarmed.
6.4.5
Trace Buffer Operation
The trace buffer is a 64 lines deep by 64-bits wide RAM array. The S12XDBG module stores trace
information in the RAM array in a circular buffer format. The RAM array can be accessed through a
register window (DBGTBH:DBGTBL) using 16-bit wide word accesses. After each complete 64-bit trace
buffer line is read, an internal pointer into the RAM is incremented so that the next read will receive fresh
information. Data is stored in the format shown in Table 6-40. After each store the counter register bits
DBGCNT[6:0] are incremented. Tracing of CPU12X activity is disabled when the BDM is active. Reading
the trace buffer whilst the DBG is armed returns invalid data and the trace buffer pointer is not
incremented.
6.4.5.1
Trace Trigger Alignment
Using the TALIGN bits (see Section 6.3.2.3”) it is possible to align the trigger with the end, the middle, or
the beginning of a tracing session.
If End or Mid tracing is selected, tracing begins when the ARM bit in DBGC1 is set and State1 is entered.
The transition to Final State if End is selected signals the end of the tracing session. The transition to Final
State if Mid is selected signals that another 32 lines will be traced before ending the tracing session.
Tracing with Begin-Trigger starts at the opcode of the trigger.
6.4.5.1.1
Storing with Begin-Trigger
Storing with Begin-Trigger, data is not stored in the Trace Buffer until the Final State is entered. Once the
trigger condition is met the S12XDBG module will remain armed until 64 lines are stored in the Trace
Buffer. If the trigger is at the address of the change-of-flow instruction the change of flow associated with
the trigger will be stored in the Trace Buffer. Using Begin-trigger together with tagging, if the tagged
instruction is about to be executed then the trace is started. Upon completion of the tracing session the
breakpoint is generated, thus the breakpoint does not occur at the tagged instruction boundary.
6.4.5.1.2
Storing with Mid-Trigger
Storing with Mid-Trigger, data is stored in the Trace Buffer as soon as the S12XDBG module is armed.
When the trigger condition is met, another 32 lines will be traced before ending the tracing session,
irrespective of the number of lines stored before the trigger occurred, then the S12XDBG module is
disarmed and no more data is stored. Using Mid-trigger with tagging, if the tagged instruction is about to
S12XS Family Reference Manual, Rev. 1.10
220
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
be executed then the trace is continued for another 32 lines. Upon tracing completion the breakpoint is
generated, thus the breakpoint does not occur at the tagged instruction boundary.
6.4.5.1.3
Storing with End-Trigger
Storing with End-Trigger, data is stored in the Trace Buffer until the Final State is entered, at which point
the S12XDBG module will become disarmed and no more data will be stored. If the trigger is at the
address of a change of flow instruction the trigger event will not be stored in the Trace Buffer.
6.4.5.2
Trace Modes
The S12XDBG module can operate in four trace modes. The mode is selected using the TRCMOD bits in
the DBGTCR register. The modes are described in the following subsections. The trace buffer organization
is shown in Table 6-40.
6.4.5.2.1
Normal Mode
In Normal Mode, change of flow (COF) program counter (PC) addresses will be stored.
COF addresses are defined as follows :
• Source address of taken conditional branches (long, short, bit-conditional, and loop primitives)
• Destination address of indexed JMP, JSR, and CALL instruction
• Destination address of RTI, RTS, and RTC instructions.
• Vector address of interrupts, except for SWI and BDM vectors
LBRA, BRA, BSR, BGND as well as non-indexed JMP, JSR, and CALL instructions are not classified as
change of flow and are not stored in the trace buffer.
Change-of-flow addresses stored include the full 23-bit address bus of CPU12X and an information byte,
which contains a source/destination bit to indicate whether the stored address was a source address or
destination address.
NOTE
When an CPU12X COF instruction with destination address is executed, the
destination address is stored to the trace buffer on instruction completion,
indicating the COF has taken place. If an interrupt occurs simultaneously
then the next instruction carried out is actually from the interrupt service
routine. The instruction at the destination address of the original program
flow gets exectuted after the interrupt service routine.
In the following example an IRQ interrupt occurs during execution of the
indexed JMP at address MARK1. The BRN at the destination (SUB_1) is
not executed until after the IRQ service routine but the destination address
is entered into the trace buffer to indicate that the indexed JMP COF has
taken place.
MARK1
MARK2
LDX
JMP
NOP
#SUB_1
0,X
; IRQ interrupt occurs during execution of this
;
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
221
S12X Debug (S12XDBGV3) Module
SUB_1
BRN
*
ADDR1
NOP
DBNE
A,PART5
IRQ_ISR
LDAB
STAB
RTI
#$F0
VAR_C1
; JMP Destination address TRACE BUFFER ENTRY 1
; RTI Destination address TRACE BUFFER ENTRY 3
;
; Source address TRACE BUFFER ENTRY 4
; IRQ Vector $FFF2 = TRACE BUFFER ENTRY 2
;
The execution flow taking into account the IRQ is as follows
MARK1
IRQ_ISR
SUB_1
ADDR1
6.4.5.2.2
LDX
JMP
LDAB
STAB
RTI
BRN
NOP
DBNE
#SUB_1
0,X
#$F0
VAR_C1
;
;
;
*
A,PART5
;
;
Loop1 Mode
Loop1 Mode, similarly to Normal Mode also stores only COF address information to the trace buffer, it
however allows the filtering out of redundant information.
The intent of Loop1 Mode is to prevent the Trace Buffer from being filled entirely with duplicate
information from a looping construct such as delays using the DBNE instruction or polling loops using
BRSET/BRCLR instructions. Immediately after address information is placed in the Trace Buffer, the
S12XDBG module writes this value into a background register. This prevents consecutive duplicate
address entries in the Trace Buffer resulting from repeated branches.
Loop1 Mode only inhibits consecutive duplicate source address entries that would typically be stored in
most tight looping constructs. It does not inhibit repeated entries of destination addresses or vector
addresses, since repeated entries of these would most likely indicate a bug in the user’s code that the
S12XDBG module is designed to help find.
6.4.5.2.3
Detail Mode
In Detail Mode, address and data for all memory and register accesses is stored in the trace buffer. This
mode also features information byte entries to the trace buffer, for each address byte entry. The information
byte indicates the size of access (word or byte) and the type of access (read or write).
When tracing CPU12X activity in Detail Mode, all cycles are traced except those when the CPU12X is
either in a free or opcode fetch cycle, the address range can be limited to a range specified by the TRANGE
bits in DBGTCR. This function uses comparators C and D to define an address range inside which
CPU12X activity should be traced (see Table 6-40). Thus the traced CPU12X activity can be restricted to
particular register range accesses.
6.4.5.2.4
Pure PC Mode
In Pure PC Mode, tracing from the CPU the PC addresses of all executed opcodes, including illegal
opcodes, are stored.
S12XS Family Reference Manual, Rev. 1.10
222
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
6.4.5.3
Trace Buffer Organization
Referring to Table 6-40. ADRH, ADRM, ADRL denote address high, middle and low byte respectively.
INF bytes contain control information (R/W, S/D etc.). The numerical suffix indicates which tracing step.
The information format for Loop1 Mode and PurePC Mode is the same as that of Normal Mode. Whilst
tracing in Normal or Loop1 modes each array line contains 2 data entries, thus in this case the DBGCNT[0]
is incremented after each separate entry. In Detail mode DBGCNT[0] remains cleared whilst the other
DBGCNT bits are incremented on each trace buffer entry.
When a COF occurs a trace buffer entry is made and the corresponding CDV bit is set.
Single byte data accesses in Detail Mode are always stored to the low byte of the trace buffer (CDATAL )
and the high byte is cleared. When tracing word accesses, the byte at the lower address is always stored to
trace buffer byte3 and the byte at the higher address is stored to byte2
Table 6-40. Trace Buffer Organization
Mode
8-Byte Wide Word Buffer
7
6
5
4
3
2
1
0
S12XCPU
Detail
CXINF1
CADRH1
CADRM1
CADRL1
CDATAH1
CDATAL1
CXINF2
CADRH2
CADRM2
CADRL2
CDATAH2
CDATAL2
CPU12X
Other Modes
CINF1
CPCH1
CPCM1
CPCL1
CINF0
CINF3
CPCH3
CPCM3
CPCL3
CINF2
CPCH0
CPCM0
CPCL0
CPCH2
CPCM2
CPCL2
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
223
S12X Debug (S12XDBGV3) Module
6.4.5.3.1
Information Byte Organization
The format of the control information byte is dependent upon the active trace mode as described below.
In Normal, Loop1, or Pure PC modes tracing of CPU12X activity, CINF is used to store control
information. In Detail Mode, CXINF contains the control information
CPU12X Information Byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CSD
CVA
0
CDV
0
0
0
0
Figure 6-23. CPU12X Information Byte CINF
Table 6-41. CINF Field Descriptions
Field
Description
7
CSD
Source Destination Indicator — This bit indicates if the corresponding stored address is a source or destination
address. This is only used in Normal and Loop1 mode tracing.
0 Source address
1 Destination address
6
CVA
Vector Indicator — This bit indicates if the corresponding stored address is a vector address.. Vector addresses
are destination addresses, thus if CVA is set, then the corresponding CSD is also set. This is only used in Normal
and Loop1 mode tracing. This bit has no meaning in Pure PC mode.
0 Indexed jump destination address
1 Vector destination address
4
CDV
Data Invalid Indicator — This bit indicates if the trace buffer entry is invalid. It is only used when tracing from
both sources in Normal, Loop1 and Pure PC modes, to indicate that the CPU12X trace buffer entry is valid.
0 Trace buffer entry is invalid
1 Trace buffer entry is valid
CXINF Information Byte
Bit 7
Bit 6
Bit 5
CSZ
CRW
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Figure 6-24. Information Byte CXINF
This describes the format of the information byte used only when tracing in Detail Mode. When tracing
from the CPU12X in Detail Mode, information is stored to the trace buffer on all cycles except opcode
fetch and free cycles. In this case the CSZ and CRW bits indicate the type of access being made by the
CPU12X.
Table 6-42. CXINF Field Descriptions
Field
Description
6
CSZ
Access Type Indicator — This bit indicates if the access was a byte or word size access.This bit only contains
valid information when tracing CPU12X activity in Detail Mode.
0 Word Access
1 Byte Access
S12XS Family Reference Manual, Rev. 1.10
224
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Table 6-42. CXINF Field Descriptions (continued)
Field
5
CRW
6.4.5.4
Description
Read Write Indicator — This bit indicates if the corresponding stored address corresponds to a read or write
access. This bit only contains valid information when tracing CPU12X activity in Detail Mode.
0 Write Access
1 Read Access
Reading Data from Trace Buffer
The data stored in the Trace Buffer can be read using either the background debug module (BDM) module
or the CPU12X provided the S12XDBG module is not armed, is configured for tracing and the system not
secured. When the ARM bit is written to 1 the trace buffer is locked to prevent reading. The trace buffer
can only be unlocked for reading by an aligned word write to DBGTB when the module is disarmed.
The Trace Buffer can only be read through the DBGTB register using aligned word reads, any byte or
misaligned reads return 0 and do not cause the trace buffer pointer to increment to the next trace buffer
address. The Trace Buffer data is read out first-in first-out. By reading CNT in DBGCNT the number of
valid 64-bit lines can be determined. DBGCNT will not decrement as data is read.
Whilst reading an internal pointer is used to determine the next line to be read. After a tracing session, the
pointer points to the oldest data entry, thus if no overflow has occurred, the pointer points to line0,
otherwise it points to the line with the oldest entry. The pointer is initialized by each aligned write to
DBGTBH to point to the oldest data again. This enables an interrupted trace buffer read sequence to be
easily restarted from the oldest data entry.
The least significant word of each 64-bit wide array line is read out first. This corresponds to the bytes 1
and 0 of Table 6-40. The bytes containing invalid information (shaded in Table 6-40) are also read out.
Reading the Trace Buffer while the S12XDBG module is armed will return invalid data and no shifting of
the RAM pointer will occur.
6.4.5.5
Trace Buffer Reset State
The Trace Buffer contents are not initialized by a system reset. Thus should a system reset occur, the trace
session information from immediately before the reset occurred can be read out. The DBGCNT bits are
not cleared by a system reset. Thus should a reset occur, the number of valid lines in the trace buffer is
indicated by DBGCNT. The internal pointer to the current trace buffer address is initialized by unlocking
the trace buffer thus points to the oldest valid data even if a reset occurred during the tracing session.
Generally debugging occurrences of system resets is best handled using mid or end trigger alignment since
the reset may occur before the trace trigger, which in the begin trigger alignment case means no
information would be stored in the trace buffer.
NOTE
An external pin RESET that occurs simultaneous to a trace buffer entry can,
in very seldom cases, lead to either that entry being corrupted or the first
entry of the session being corrupted. In such cases the other contents of the
trace buffer still contain valid tracing information. The case occurs when the
reset assertion coincides with the trace buffer entry clock edge.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
225
S12X Debug (S12XDBGV3) Module
6.4.6
Tagging
A tag follows program information as it advances through the instruction queue. When a tagged instruction
reaches the head of the queue a tag hit occurs and triggers the state sequencer.
Each comparator control register features a TAG bit, which controls whether the comparator match will
cause a trigger immediately or tag the opcode at the matched address. If a comparator is enabled for tagged
comparisons, the address stored in the comparator match address registers must be an opcode address for
the trigger to occur.
Using Begin trigger together with tagging, if the tagged instruction is about to be executed then the
transition to the next state sequencer state occurs. If the transition is to the Final State, tracing is started.
Only upon completion of the tracing session can a breakpoint be generated. Similarly using Mid trigger
with tagging, if the tagged instruction is about to be executed then the trace is continued for another 32
lines. Upon tracing completion the breakpoint is generated. Using End trigger, when the tagged instruction
is about to be executed and the next transition is to Final State then a breakpoint is generated immediately,
before the tagged instruction is carried out.
Read/Write (R/W), access size (SZ) monitoring and data bus monitoring is not useful if tagged triggering
is selected, since the tag is attached to the opcode at the matched address and is not dependent on the data
bus nor on the type of access. Thus these bits are ignored if tagged triggering is selected.
When configured for range comparisons and tagging, the ranges are accurate only to word boundaries.
S12X tagging is disabled when the BDM becomes active.
6.4.7
Breakpoints
Breakpoints can be generated as follows.
• From comparator channel triggers to final state.
• Using software to write to the TRIG bit in the DBGC1 register.
Breakpoints generated via the BDM BACKGROUND command have no affect on the CPU12X in STOP
or WAIT mode.
6.4.7.1
Breakpoints From Internal Comparator Channel Final State Triggers
Breakpoints can be generated when internal comparator channels trigger the state sequencer to the Final
State. If configured for tagging, then the breakpoint is generated when the tagged opcode reaches the
execution stage of the instruction queue.
If a tracing session is selected by TSOURCE, breakpoints are requested when the tracing session has
completed, thus if Begin or Mid aligned triggering is selected, the breakpoint is requested only on
completion of the subsequent trace (see Table 6-43). If no tracing session is selected, breakpoints are
requested immediately.
If the BRK bit is set on the triggering channel, then the breakpoint is generated immediately independent
of tracing trigger alignment.
S12XS Family Reference Manual, Rev. 1.10
226
Freescale Semiconductor
S12X Debug (S12XDBGV3) Module
Table 6-43. Breakpoint Setup
BRK
TALIGN
DBGBRK
Breakpoint Alignment
0
00
0
Fill Trace Buffer until trigger
(no breakpoints — keep running)
0
00
1
Fill Trace Buffer until trigger, then breakpoint request occurs
0
01
0
Start Trace Buffer at trigger
(no breakpoints — keep running)
0
01
1
Start Trace Buffer at trigger
A breakpoint request occurs when Trace Buffer is full
0
10
0
Store a further 32 Trace Buffer line entries after trigger
(no breakpoints — keep running)
0
10
1
Store a further 32 Trace Buffer line entries after trigger
Request breakpoint after the 32 further Trace Buffer entries
1
00,01,10
1
Terminate tracing and generate breakpoint immediately on trigger
1
00,01,10
0
Terminate tracing immediately on trigger
x
11
x
Reserved
6.4.7.2
Breakpoints Generated Via The TRIG Bit
If a TRIG triggers occur, the Final State is entered. If a tracing session is selected by TSOURCE,
breakpoints are requested when the tracing session has completed, thus if Begin or Mid aligned triggering
is selected, the breakpoint is requested only on completion of the subsequent trace (see Table 6-43). If no
tracing session is selected, breakpoints are requested immediately. TRIG breakpoints are possible even if
the S12XDBG module is disarmed.
6.4.7.3
S12XDBG Breakpoint Priorities
If a TRIG trigger occurs after Begin or Mid aligned tracing has already been triggered by a comparator
instigated transition to Final State, then TRIG no longer has an effect. When the associated tracing session
is complete, the breakpoint occurs. Similarly if a TRIG is followed by a subsequent trigger from a
comparator channel, it has no effect, since tracing has already started.
6.4.7.3.1
S12XDBG Breakpoint Priorities And BDM Interfacing
Breakpoint operation is dependent on the state of the S12XBDM module. If the S12XBDM module is
active, the CPU12X is executing out of BDM firmware and S12X breakpoints are disabled. In addition,
while executing a BDM TRACE command, tagging into BDM is disabled. If BDM is not active, the
breakpoint will give priority to BDM requests over SWI requests if the breakpoint coincides with a SWI
instruction in the user’s code. On returning from BDM, the SWI from user code gets executed.
Table 6-44. Breakpoint Mapping Summary
DBGBRK
(DBGC1[3])
BDM Bit
(DBGC1[4])
BDM
Enabled
BDM
Active
S12X Breakpoint
Mapping
0
X
X
X
No Breakpoint
1
0
X
0
Breakpoint to SWI
1
0
X
1
No Breakpoint
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
227
S12X Debug (S12XDBGV3) Module
Table 6-44. Breakpoint Mapping Summary
1
1
0
X
Breakpoint to SWI
1
1
1
0
Breakpoint to BDM
1
1
1
1
No Breakpoint
BDM cannot be entered from a breakpoint unless the ENABLE bit is set in the BDM. If entry to BDM via
a BGND instruction is attempted and the ENABLE bit in the BDM is cleared, the CPU12X actually
executes the BDM firmware code. It checks the ENABLE and returns if ENABLE is not set. If not serviced
by the monitor then the breakpoint is re-asserted when the BDM returns to normal CPU12X flow.
If the comparator register contents coincide with the SWI/BDM vector address then an SWI in user code
and DBG breakpoint could occur simultaneously. The CPU12X ensures that BDM requests have a higher
priority than SWI requests. Returning from the BDM/SWI service routine care must be taken to avoid re
triggering a breakpoint.
NOTE
When program control returns from a tagged breakpoint using an RTI or
BDM GO command without program counter modification it will return to
the instruction whose tag generated the breakpoint. To avoid re triggering a
breakpoint at the same location reconfigure the S12XDBG module in the
SWI routine, if configured for an SWI breakpoint, or over the BDM
interface by executing a TRACE command before the GO to increment the
program flow past the tagged instruction.
S12XS Family Reference Manual, Rev. 1.10
228
Freescale Semiconductor
Chapter 7
Security (S12XS9SECV2)
Table 7-1. Revision History
Version
Number
Revision
Date
Effective
Date
02.00
27 Aug
2004
08 Sep
2004
reviewed and updated for S12XD architecture
02.01
21 Feb
2007
21 Feb
2007
added S12XE, S12XF and S12XS architectures
02.02
19 Apr
2007
19 Apr
2007
corrected statement about Backdoor key access via BDM on XE, XF,
XS
7.1
Author
Description of Changes
Introduction
This specification describes the function of the security mechanism in the S12XS chip family (9SEC).
NOTE
No security feature is absolutely secure. However, Freescale’s strategy is to
make reading or copying the FLASH and/or EEPROM difficult for
unauthorized users.
7.1.1
Features
The user must be reminded that part of the security must lie with the application code. An extreme example
would be application code that dumps the contents of the internal memory. This would defeat the purpose
of security. At the same time, the user may also wish to put a backdoor in the application program. An
example of this is the user downloads a security key through the SCI, which allows access to a
programming routine that updates parameters stored in another section of the Flash memory.
The security features of the S12XS chip family (in secure mode) are:
• Protect the content of non-volatile memories (Flash, EEPROM)
• Execution of NVM commands is restricted
• Disable access to internal memory via background debug module (BDM)
Table 7-2 gives an overview over availability of security relevant features in unsecure and secure modes.
Table 7-2. Feature Availability in Unsecure and Secure Modes on S12XS
Unsecure Mode
Flash Array Access
NS
SS
✔
✔
NX
ES
Secure Mode
EX
ST
NS
SS
✔
✔
NX
ES
EX
ST
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
229
Security (S12XS9SECV2)
Table 7-2. Feature Availability in Unsecure and Secure Modes on S12XS
Unsecure Mode
NS
SS
EEPROM Array Access
✔
NVM Commands
BDM
NX
ES
Secure Mode
EX
ST
NS
SS
✔
✔
✔
✔1
✔
✔1
✔1
✔
✔
—
✔2
NX
ES
EX
ST
DBG Module Trace
✔
✔
—
—
Restricted
NVM
command
set
only.
Please
refer
to
the
NVM
wrapper
block
guides
for detailed information.
1
BDM
hardware
commands
restricted
to
peripheral
registers
only.
2
7.1.2
Modes of Operation
7.1.3
Securing the Microcontroller
Once the user has programmed the Flash and EEPROM, the chip can be secured by programming the
security bits located in the options/security byte in the Flash memory array. These non-volatile bits will
keep the device secured through reset and power-down.
The options/security byte is located at address 0xFF0F (= global address 0x7F_FF0F) in the Flash memory
array. This byte can be erased and programmed like any other Flash location. Two bits of this byte are used
for security (SEC[1:0]). On devices which have a memory page window, the Flash options/security byte
is also available at address 0xBF0F by selecting page 0x3F with the PPAGE register. The contents of this
byte are copied into the Flash security register (FSEC) during a reset sequence.
0xFF0F
7
6
5
4
3
2
1
0
KEYEN1
KEYEN0
NV5
NV4
NV3
NV2
SEC1
SEC0
Figure 7-1. Flash Options/Security Byte
The meaning of the bits KEYEN[1:0] is shown in Table 7-3. Please refer to Section 7.1.5.1, “Unsecuring
the MCU Using the Backdoor Key Access” for more information.
Table 7-3. Backdoor Key Access Enable Bits
KEYEN[1:0]
Backdoor Key
Access Enabled
00
0 (disabled)
01
0 (disabled)
10
1 (enabled)
11
0 (disabled)
The meaning of the security bits SEC[1:0] is shown in Table 7-4. For security reasons, the state of device
security is controlled by two bits. To put the device in unsecured mode, these bits must be programmed to
S12XS Family Reference Manual, Rev. 1.10
230
Freescale Semiconductor
Security (S12XS9SECV2)
SEC[1:0] = ‘10’. All other combinations put the device in a secured mode. The recommended value to put
the device in secured state is the inverse of the unsecured state, i.e. SEC[1:0] = ‘01’.
Table 7-4. Security Bits
SEC[1:0]
Security State
00
1 (secured)
01
1 (secured)
10
0 (unsecured)
11
1 (secured)
NOTE
Please refer to the Flash block guide for actual security configuration (in
section “Flash Module Security”).
7.1.4
Operation of the Secured Microcontroller
By securing the device, unauthorized access to the EEPROM and Flash memory contents can be prevented.
However, it must be understood that the security of the EEPROM and Flash memory contents also depends
on the design of the application program. For example, if the application has the capability of downloading
code through a serial port and then executing that code (e.g. an application containing bootloader code),
then this capability could potentially be used to read the EEPROM and Flash memory contents even when
the microcontroller is in the secure state. In this example, the security of the application could be enhanced
by requiring a challenge/response authentication before any code can be downloaded.
Secured operation has the following effects on the microcontroller:
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
231
Security (S12XS9SECV2)
7.1.4.1
•
•
•
Background debug module (BDM) operation is completely disabled.
Execution of Flash and EEPROM commands is restricted. Please refer to the NVM block guide for
details.
Tracing code execution using the DBG module is disabled.
7.1.4.2
•
•
•
•
Normal Single Chip Mode (NS)
Special Single Chip Mode (SS)
BDM firmware commands are disabled.
BDM hardware commands are restricted to the register space.
Execution of Flash and EEPROM commands is restricted. Please refer to the NVM block guide for
details.
Tracing code execution using the DBG module is disabled.
Special single chip mode means BDM is active after reset. The availability of BDM firmware commands
depends on the security state of the device. The BDM secure firmware first performs a blank check of both
the Flash memory and the EEPROM. If the blank check succeeds, security will be temporarily turned off
and the state of the security bits in the appropriate Flash memory location can be changed If the blank
check fails, security will remain active, only the BDM hardware commands will be enabled, and the
accessible memory space is restricted to the peripheral register area. This will allow the BDM to be used
to erase the EEPROM and Flash memory without giving access to their contents. After erasing both Flash
memory and EEPROM, another reset into special single chip mode will cause the blank check to succeed
and the options/security byte can be programmed to “unsecured” state via BDM.
While the BDM is executing the blank check, the BDM interface is completely blocked, which means that
all BDM commands are temporarily blocked.
S12XS Family Reference Manual, Rev. 1.10
232
Freescale Semiconductor
Security (S12XS9SECV2)
7.1.5
Unsecuring the Microcontroller
Unsecuring the microcontroller can be done by three different methods:
1. Backdoor key access
2. Reprogramming the security bits
3. Complete memory erase (special modes)
7.1.5.1
Unsecuring the MCU Using the Backdoor Key Access
In normal modes (single chip and expanded), security can be temporarily disabled using the backdoor key
access method. This method requires that:
• The backdoor key at 0xFF00–0xFF07 (= global addresses 0x7F_FF00–0x7F_FF07) has been
programmed to a valid value.
• The KEYEN[1:0] bits within the Flash options/security byte select ‘enabled’.
• In single chip mode, the application program programmed into the microcontroller must be
designed to have the capability to write to the backdoor key locations.
The backdoor key values themselves would not normally be stored within the application data, which
means the application program would have to be designed to receive the backdoor key values from an
external source (e.g. through a serial port).
The backdoor key access method allows debugging of a secured microcontroller without having to erase
the Flash. This is particularly useful for failure analysis.
NOTE
No word of the backdoor key is allowed to have the value 0x0000 or
0xFFFF.
7.1.6
Reprogramming the Security Bits
In normal single chip mode (NS), security can also be disabled by erasing and reprogramming the security
bits within Flash options/security byte to the unsecured value. Because the erase operation will erase the
entire sector from 0xFE00–0xFFFF (0x7F_FE00–0x7F_FFFF), the backdoor key and the interrupt vectors
will also be erased; this method is not recommended for normal single chip mode. The application
software can only erase and program the Flash options/security byte if the Flash sector containing the Flash
options/security byte is not protected (see Flash protection). Thus Flash protection is a useful means of
preventing this method. The microcontroller will enter the unsecured state after the next reset following
the programming of the security bits to the unsecured value.
This method requires that:
• The application software previously programmed into the microcontroller has been designed to
have the capability to erase and program the Flash options/security byte, or security is first disabled
using the backdoor key method, allowing BDM to be used to issue commands to erase and program
the Flash options/security byte.
• The Flash sector containing the Flash options/security byte is not protected.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
233
Security (S12XS9SECV2)
7.1.7
Complete Memory Erase (Special Modes)
The microcontroller can be unsecured in special modes by erasing the entire EEPROM and Flash memory
contents.
When a secure microcontroller is reset into special single chip mode (SS), the BDM firmware verifies
whether the EEPROM and Flash memory are erased. If any EEPROM or Flash memory address is not
erased, only BDM hardware commands are enabled. BDM hardware commands can then be used to write
to the EEPROM and Flash registers to mass erase the EEPROM and all Flash memory blocks.
When next reset into special single chip mode, the BDM firmware will again verify whether all EEPROM
and Flash memory are erased, and this being the case, will enable all BDM commands, allowing the Flash
options/security byte to be programmed to the unsecured value. The security bits SEC[1:0] in the Flash
security register will indicate the unsecure state following the next reset.
S12XS Family Reference Manual, Rev. 1.10
234
Freescale Semiconductor
Chapter 8
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-1. Revision History
Revision
Number
Revision
Date
V01.00
26 Oct. 2005
V01.01
02 Nov 2006
8.4.1.1/8-252
Table “Examples of IPLL Divider settings”: corrected $32 to $31
V01.02
4 Mar. 2008
8.4.1.4/8-255
8.4.3.3/8-259
Corrected details
V01.03
1 Sep. 2008
Table 8-14
V01.04
20 Nov. 2008
8.3.2.4/8-241
V01.05
19. Sep 2009
8.5.1/8-261
8.1
Sections
Affected
Description of Changes
Initial release
added 100MHz example for PLL
S12XECRG Flags Register: corrected address to Module Base + 0x0003
Modified Note below Table 8-17./8-261
Introduction
This specification describes the function of the Clocks and Reset Generator (S12XECRG).
8.1.1
Features
The main features of this block are:
• Phase Locked Loop (IPLL) frequency multiplier with internal filter
— Reference divider
— Post divider
— Configurable internal filter (no external pin)
— Optional frequency modulation for defined jitter and reduced emission
— Automatic frequency lock detector
— Interrupt request on entry or exit from locked condition
— Self Clock Mode in absence of reference clock
• System Clock Generator
— Clock Quality Check
— User selectable fast wake-up from Stop in Self-Clock Mode for power saving and immediate
program execution
— Clock switch for either Oscillator or PLL based system clocks
• Computer Operating Properly (COP) watchdog timer with time-out clear window.
• System Reset generation from the following possible sources:
— Power on reset
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
235
S12XE Clocks and Reset Generator (S12XECRGV1)
•
8.1.2
— Low voltage reset
— Illegal address reset
— COP reset
— Loss of clock reset
— External pin reset
Real-Time Interrupt (RTI)
Modes of Operation
This subsection lists and briefly describes all operating modes supported by the S12XECRG.
• Run Mode
All functional parts of the S12XECRG are running during normal Run Mode. If RTI or COP
functionality is required the individual bits of the associated rate select registers (COPCTL,
RTICTL) have to be set to a non zero value.
• Wait Mode
In this mode the IPLL can be disabled automatically depending on the PLLWAI bit.
• Stop Mode
Depending on the setting of the PSTP bit Stop Mode can be differentiated between Full Stop Mode
(PSTP = 0) and Pseudo Stop Mode (PSTP = 1).
— Full Stop Mode
The oscillator is disabled and thus all system and core clocks are stopped. The COP and the
RTI remain frozen.
— Pseudo Stop Mode
The oscillator continues to run and most of the system and core clocks are stopped. If the
respective enable bits are set the COP and RTI will continue to run, else they remain frozen.
• Self Clock Mode
Self Clock Mode will be entered if the Clock Monitor Enable Bit (CME) and the Self Clock Mode
Enable Bit (SCME) are both asserted and the clock monitor in the oscillator block detects a loss of
clock. As soon as Self Clock Mode is entered the S12XECRG starts to perform a clock quality
check. Self Clock Mode remains active until the clock quality check indicates that the required
quality of the incoming clock signal is met (frequency and amplitude). Self Clock Mode should be
used for safety purposes only. It provides reduced functionality to the MCU in case a loss of clock
is causing severe system conditions.
8.1.3
Block Diagram
Figure 8-1 shows a block diagram of the S12XECRG.
S12XS Family Reference Manual, Rev. 1.10
236
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
Illegal Address Reset
S12X_MMC
Power on Reset
Voltage
Regulator
Low Voltage Reset
ICRG
RESET
CM Fail
Clock
Monitor
OSCCLK
EXTAL
Oscillator
XTAL
COP Timeout
XCLKS
Reset
Generator
Clock Quality
Checker
System Reset
Bus Clock
Core Clock
COP
RTI
Oscillator Clock
Registers
PLLCLK
VDDPLL
IPLL
VSSPLL
Real Time Interrupt
Clock and Reset Control
PLL Lock Interrupt
Self Clock Mode
Interrupt
Figure 8-1. Block diagram of S12XECRG
8.2
Signal Description
This section lists and describes the signals that connect off chip.
8.2.1
VDDPLL, VSSPLL
These pins provides operating voltage (VDDPLL) and ground (VSSPLL) for the IPLL circuitry. This allows
the supply voltage to the IPLL to be independently bypassed. Even if IPLL usage is not required VDDPLL
and VSSPLL must be connected to properly.
8.2.2
RESET
RESET is an active low bidirectional reset pin. As an input it initializes the MCU asynchronously to a
known start-up state. As an open-drain output it indicates that an system reset (internal to MCU) has been
triggered.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
237
S12XE Clocks and Reset Generator (S12XECRGV1)
8.3
Memory Map and Registers
This section provides a detailed description of all registers accessible in the S12XECRG.
8.3.1
Module Memory Map
Figure 8-2 gives an overview on all S12XECRG registers.
Address
Name
0x0000
SYNR
0x0001
REFDV
0x0002
POSTDIV
0x0003
CRGFLG
0x0004
CRGINT
0x0005
CLKSEL
0x0006
PLLCTL
0x0007
RTICTL
0x0008
COPCTL
0x0009
FORBYP2
0x000A
CTCTL2
0x000B
ARMCOP
Bit 7
R
W
R
W
R
6
5
4
3
VCOFRQ[1:0]
SYNDIV[5:0]
REFFRQ[1:0]
REFDIV[5:0]
0
0
0
RTIF
PORF
LVRF
W
R
0
0
W
R
RTIE
LOCKIF
LOCKIE
LOCK
0
XCLKS
0
PLLON
FM1
FM0
FSTWKP
RTDEC
RTR6
RTR5
RTR4
RTR3
WCOP
RSBCK
0
0
0
0
0
0
0
0
0
0
R
0
0
W
Bit 7
Bit 6
W
R
W
R
W
R
W
R
PLLSEL
PSTP
CME
1
Bit 0
POSTDIV[4:0]
W
R
2
PLLWAI
ILAF
0
0
SCMIF
SCMIE
SCM
0
RTIWAI
COPWAI
PRE
PCE
SCME
RTR2
RTR1
RTR0
CR2
CR1
CR0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
WRTMASK
W
R
W
2. FORBYP and CTCTL are intended for factory test purposes only.
= Unimplemented or Reserved
Figure 8-2. CRG Register Summary
NOTE
Register Address = Base Address + Address Offset, where the Base Address
is defined at the MCU level and the Address Offset is defined at the module
level.
S12XS Family Reference Manual, Rev. 1.10
238
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
8.3.2
Register Descriptions
This section describes in address order all the S12XECRG registers and their individual bits.
8.3.2.1
S12XECRG Synthesizer Register (SYNR)
The SYNR register controls the multiplication factor of the IPLL and selects the VCO frequency range.
Module Base + 0x0000
7
6
5
4
3
2
1
0
0
0
0
R
VCOFRQ[1:0]
SYNDIV[5:0]
W
Reset
0
0
0
0
0
Figure 8-3. S12XECRG Synthesizer Register (SYNR)
Read: Anytime
Write: Anytime except if PLLSEL = 1
NOTE
Write to this register initializes the lock detector bit.
( SYNDIV + 1 )
f VCO = 2 × f OSC × ------------------------------------( REFDIV + 1 )
f VCO
f PLL = -----------------------------------2 × POSTDIV
f PLL
f BUS = ------------2
NOTE
fVCO must be within the specified VCO frequency lock range. F.BUS (Bus
Clock) must not exceed the specified maximum. If POSTDIV = $00 then
fPLL is same as fVCO (divide by one).
The VCOFRQ[1:0] bit are used to configure the VCO gain for optimal stability and lock time. For correct
IPLL operation the VCOFRQ[1:0] bits have to be selected according to the actual target VCOCLK
frequency as shown in Table 8-2. Setting the VCOFRQ[1:0] bits wrong can result in a non functional IPLL
(no locking and/or insufficient stability).
Table 8-2. VCO Clock Frequency Selection
VCOCLK Frequency Ranges
VCOFRQ[1:0]
32MHz <= fVCO<= 48MHz
00
48MHz < fVCO<= 80MHz
01
Reserved
10
80MHz < fVCO <= 120MHz
11
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
239
S12XE Clocks and Reset Generator (S12XECRGV1)
8.3.2.2
S12XECRG Reference Divider Register (REFDV)
The REFDV register provides a finer granularity for the IPLL multiplier steps.
Module Base + 0x0001
7
6
5
4
3
2
1
0
0
0
0
R
REFFRQ[1:0]
REFDIV[5:0]
W
Reset
0
0
0
0
0
Figure 8-4. S12XECRG Reference Divider Register (REFDV)
Read: Anytime
Write: Anytime except when PLLSEL = 1
NOTE
Write to this register initializes the lock detector bit.
f OSC
f REF = -----------------------------------( REFDIV + 1 )
The REFFRQ[1:0] bit are used to configure the internal PLL filter for optimal stability and lock time. For
correct IPLL operation the REFFRQ[1:0] bits have to be selected according to the actual REFCLK
frequency as shown in Figure 8-3. Setting the REFFRQ[1:0] bits wrong can result in a non functional IPLL
(no locking and/or insufficient stability).
Table 8-3. Reference Clock Frequency Selection
8.3.2.3
REFCLK Frequency Ranges
REFFRQ[1:0]
1MHz <= fREF <= 2MHz
00
2MHz < fREF <= 6MHz
01
6MHz < fREF <= 12MHz
10
fREF >12MHz
11
S12XECRG Post Divider Register (POSTDIV)
The POSTDIV register controls the frequency ratio between the VCOCLK and PLLCLK. The count in the
final divider divides VCOCLK frequency by 1 or 2*POSTDIV. Note that if POSTDIV = $00 fPLL= fVCO
(divide by one).
S12XS Family Reference Manual, Rev. 1.10
240
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
Module Base + 0x0002
R
7
6
5
0
0
0
4
3
2
1
0
0
0
2
1
0
ILAF
SCMIF
0
0
POSTDIV[4:0]
W
Reset
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 8-5. S12XECRG Post Divider Register (POSTDIV)
Read: Anytime
Write: Anytime except if PLLSEL = 1
f VCO
f PLL = -------------------------------------( 2xPOSTDIV )
NOTE
If POSTDIV = $00 then fPLL is identical to fVCO (divide by one).
8.3.2.4
S12XECRG Flags Register (CRGFLG)
This register provides S12XECRG status bits and flags.
Module Base + 0x0003
7
6
5
4
RTIF
PORF
LVRF
LOCKIF
0
Note 1
Note 2
Note 3
R
3
LOCK
SCM
W
Reset
0
0
1. PORF is set to 1 when a power on reset occurs. Unaffected by system reset.
2. LVRF is set to 1 when a low voltage reset occurs. Unaffected by system reset.
3. ILAF is set to 1 when an illegal address reset occurs. Unaffected by system reset. Cleared by power on or low voltage reset.
= Unimplemented or Reserved
Figure 8-6. S12XECRG Flags Register (CRGFLG)
Read: Anytime
Write: Refer to each bit for individual write conditions
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
241
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-4. CRGFLG Field Descriptions
Field
Description
7
RTIF
Real Time Interrupt Flag — RTIF is set to 1 at the end of the RTI period. This flag can only be cleared by writing
a 1. Writing a 0 has no effect. If enabled (RTIE=1), RTIF causes an interrupt request.
0 RTI time-out has not yet occurred.
1 RTI time-out has occurred.
6
PORF
Power on Reset Flag — PORF is set to 1 when a power on reset occurs. This flag can only be cleared by writing
a 1. Writing a 0 has no effect.
0 Power on reset has not occurred.
1 Power on reset has occurred.
5
LVRF
Low Voltage Reset Flag — LVRF is set to 1 when a low voltage reset occurs. This flag can only be cleared by
writing a 1. Writing a 0 has no effect.
0 Low voltage reset has not occurred.
1 Low voltage reset has occurred.
4
LOCKIF
IPLL Lock Interrupt Flag — LOCKIF is set to 1 when LOCK status bit changes. This flag can only be cleared
by writing a 1. Writing a 0 has no effect.If enabled (LOCKIE=1), LOCKIF causes an interrupt request.
0 No change in LOCK bit.
1 LOCK bit has changed.
3
LOCK
Lock Status Bit — LOCK reflects the current state of IPLL lock condition. This bit is cleared in Self Clock Mode.
Writes have no effect.
0 VCOCLK is not within the desired tolerance of the target frequency.
1 VCOCLK is within the desired tolerance of the target frequency.
2
ILAF
Illegal Address Reset Flag — ILAF is set to 1 when an illegal address reset occurs. Refer to S12XMMC Block
Guide for details. This flag can only be cleared by writing a 1. Writing a 0 has no effect.
0 Illegal address reset has not occurred.
1 Illegal address reset has occurred.
1
SCMIF
0
SCM
8.3.2.5
Self Clock Mode Interrupt Flag — SCMIF is set to 1 when SCM status bit changes. This flag can only be
cleared by writing a 1. Writing a 0 has no effect. If enabled (SCMIE=1), SCMIF causes an interrupt request.
0 No change in SCM bit.
1 SCM bit has changed.
Self Clock Mode Status Bit — SCM reflects the current clocking mode. Writes have no effect.
0 MCU is operating normally with OSCCLK available.
1 MCU is operating in Self Clock Mode with OSCCLK in an unknown state. All clocks are derived from PLLCLK
running at its minimum frequency fSCM.
S12XECRG Interrupt Enable Register (CRGINT)
This register enables S12XECRG interrupt requests.
Module Base + 0x0004
7
R
6
5
0
0
RTIE
4
3
2
0
0
LOCKIE
1
0
0
SCMIE
W
Reset
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 8-7. S12XECRG Interrupt Enable Register (CRGINT)
S12XS Family Reference Manual, Rev. 1.10
242
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
Read: Anytime
Write: Anytime
Table 8-5. CRGINT Field Descriptions
Field
7
RTIE
Description
Real Time Interrupt Enable Bit
0 Interrupt requests from RTI are disabled.
1 Interrupt will be requested whenever RTIF is set.
4
LOCKIE
Lock Interrupt Enable Bit
0 LOCK interrupt requests are disabled.
1 Interrupt will be requested whenever LOCKIF is set.
1
SCMIE
Self Clock Mode Interrupt Enable Bit
0 SCM interrupt requests are disabled.
1 Interrupt will be requested whenever SCMIF is set.
8.3.2.6
S12XECRG Clock Select Register (CLKSEL)
This register controls S12XECRG clock selection. Refer toFigure 8-16 for more details on the effect of each
bit.
Module Base + 0x0005
7
6
PLLSEL
PSTP
0
0
R
5
4
XCLKS
0
3
2
1
0
RTIWAI
COPWAI
0
0
0
PLLWAI
W
Reset
0
0
0
0
= Unimplemented or Reserved
Figure 8-8. S12XECRG Clock Select Register (CLKSEL)
Read: Anytime
Write: Refer to each bit for individual write conditions
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
243
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-6. CLKSEL Field Descriptions
Field
7
PLLSEL
6
PSTP
Description
PLL Select Bit
Write: Anytime.
Writing a one when LOCK=0 has no effect. This prevents the selection of an unstable PLLCLK as SYSCLK.
PLLSEL bit is cleared when the MCU enters Self Clock Mode, Stop Mode or Wait Mode with PLLWAI bit set.
It is recommended to read back the PLLSEL bit to make sure PLLCLK has really been selected as
SYSCLK, as LOCK status bit could theoretically change at the very moment writing the PLLSEL bit.
0 System clocks are derived from OSCCLK (fBUS = fOSC / 2).
1 System clocks are derived from PLLCLK (fBUS = fPLL / 2).
Pseudo Stop Bit
Write: Anytime
This bit controls the functionality of the oscillator during Stop Mode.
0 Oscillator is disabled in Stop Mode.
1 Oscillator continues to run in Stop Mode (Pseudo Stop).
Note: Pseudo Stop Mode allows for faster STOP recovery and reduces the mechanical stress and aging of the
resonator in case of frequent STOP conditions at the expense of a slightly increased power consumption.
5
XCLKS
Oscillator Configuration Status Bit — This read-only bit shows the oscillator configuration status.
0 Loop controlled Pierce Oscillator is selected.
1 External clock / full swing Pierce Oscillator is selected.
3
PLLWAI
PLL Stops in Wait Mode Bit
Write: Anytime
If PLLWAI is set, the S12XECRG will clear the PLLSEL bit before entering Wait Mode. The PLLON bit remains
set during Wait Mode but the IPLL is powered down. Upon exiting Wait Mode, the PLLSEL bit has to be set
manually if PLL clock is required.
0 IPLL keeps running in Wait Mode.
1 IPLL stops in Wait Mode.
1
RTIWAI
RTI Stops in Wait Mode Bit
Write: Anytime
0 RTI keeps running in Wait Mode.
1 RTI stops and initializes the RTI dividers whenever the part goes into Wait Mode.
0
COPWAI
COP Stops in Wait Mode Bit
Normal modes: Write once
Special modes: Write anytime
0 COP keeps running in Wait Mode.
1 COP stops and initializes the COP counter whenever the part goes into Wait Mode.
8.3.2.7
S12XECRG IPLL Control Register (PLLCTL)
This register controls the IPLL functionality.
Module Base + 0x0006
7
6
5
4
3
2
1
0
CME
PLLON
FM1
FM0
FSTWKP
PRE
PCE
SCME
1
1
0
0
0
0
0
1
R
W
Reset
Figure 8-9. S12XECRG IPLL Control Register (PLLCTL)
S12XS Family Reference Manual, Rev. 1.10
244
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
Read: Anytime
Write: Refer to each bit for individual write conditions
Table 8-7. PLLCTL Field Descriptions
Field
Description
7
CME
Clock Monitor Enable Bit — CME enables the clock monitor. Write anytime except when SCM = 1.
0 Clock monitor is disabled.
1 Clock monitor is enabled. Slow or stopped clocks will cause a clock monitor reset sequence or Self Clock
Mode.
Note: Operating with CME=0 will not detect any loss of clock. In case of poor clock quality this could cause
unpredictable operation of the MCU!
In Stop Mode (PSTP=0) the clock monitor is disabled independently of the CME bit setting and any loss
of external clock will not be detected.
Also after wake-up from stop mode (PSTP = 0) with fast wake-up enabled (FSTWKP = 1) the clock monitor
is disabled independently of the CME bit setting and any loss of external clock will not be detected.
6
PLLON
Phase Lock Loop On Bit — PLLON turns on the IPLL circuitry. In Self Clock Mode, the IPLL is turned on, but
the PLLON bit reads the last written value. Write anytime except when PLLSEL = 1.
0 IPLL is turned off.
1 IPLL is turned on.
5, 4
FM1, FM0
IPLL Frequency Modulation Enable Bit — FM1 and FM0 enable additional frequency modulation on the
VCOCLK. This is to reduce noise emission. The modulation frequency is fref divided by 16. Write anytime except
when PLLSEL = 1. See Table 8-8 for coding.
3
FSTWKP
Fast Wake-up from Full Stop Bit — FSTWKP enables fast wake-up from full stop mode. Write anytime. If SelfClock Mode is disabled (SCME = 0) this bit has no effect.
0 Fast wake-up from full stop mode is disabled.
1 Fast wake-up from full stop mode is enabled. When waking up from full stop mode the system will immediately
resume operation in Self-Clock Mode (see Section 8.4.1.4, “Clock Quality Checker”). The SCMIF flag will not
be set. The system will remain in Self-Clock Mode with oscillator and clock monitor disabled until FSTWKP bit
is cleared. The clearing of FSTWKP will start the oscillator, the clock monitor and the clock quality check. If
the clock quality check is successful, the S12XECRG will switch all system clocks to OSCCLK. The SCMIF
flag will be set. See application examples in Figure 8-19 and Figure 8-20.
2
PRE
RTI Enable During Pseudo Stop Bit — PRE enables the RTI during Pseudo Stop Mode.
Write anytime.
0 RTI stops running during Pseudo Stop Mode.
1 RTI continues running during Pseudo Stop Mode.
Note: If the PRE bit is cleared the RTI dividers will go static while Pseudo Stop Mode is active. The RTI dividers
will not initialize like in Wait Mode with RTIWAI bit set.
1
PCE
COP Enable During Pseudo Stop Bit — PCE enables the COP during Pseudo Stop Mode.
Write anytime.
0 COP stops running during Pseudo Stop Mode
1 COP continues running during Pseudo Stop Mode
Note: If the PCE bit is cleared the COP dividers will go static while Pseudo Stop Mode is active. The COP
dividers will not initialize like in Wait Mode with COPWAI bit set.
0
SCME
Self Clock Mode Enable Bit
Normal modes: Write once
Special modes: Write anytime
SCME can not be cleared while operating in Self Clock Mode (SCM = 1).
0 Detection of crystal clock failure causes clock monitor reset (see Section 8.5.1.1, “Clock Monitor Reset”).
1 Detection of crystal clock failure forces the MCU in Self Clock Mode (see Section 8.4.2.2, “Self Clock Mode”).
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
245
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-8. FM Amplitude selection
FM1
8.3.2.8
FM Amplitude /
fVCO Variation
FM0
0
0
FM off
0
1
±1%
1
0
±2%
1
1
±4%
S12XECRG RTI Control Register (RTICTL)
This register selects the timeout period for the Real Time Interrupt.
Module Base + 0x0007
7
6
5
4
3
2
1
0
RTDEC
RTR6
RTR5
RTR4
RTR3
RTR2
RTR1
RTR0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 8-10. S12XECRG RTI Control Register (RTICTL)
Read: Anytime
Write: Anytime
NOTE
A write to this register initializes the RTI counter.
Table 8-9. RTICTL Field Descriptions
Field
Description
7
RTDEC
Decimal or Binary Divider Select Bit — RTDEC selects decimal or binary based prescaler values.
0 Binary based divider value. See Table 8-10
1 Decimal based divider value. See Table 8-11
6–4
RTR[6:4]
Real Time Interrupt Prescale Rate Select Bits — These bits select the prescale rate for the RTI. See Table 810 and Table 8-11.
3–0
RTR[3:0]
Real Time Interrupt Modulus Counter Select Bits — These bits select the modulus counter target value to
provide additional granularity.Table 8-10 and Table 8-11 show all possible divide values selectable by the
RTICTL register. The source clock for the RTI is OSCCLK.
Table 8-10. RTI Frequency Divide Rates for RTDEC = 0
RTR[6:4] =
RTR[3:0]
0000 (÷1)
000
(OFF)
001
(210)
010
(211)
011
(212)
100
(213)
101
(214)
110
(215)
111
(216)
OFF1
210
211
212
213
214
215
216
S12XS Family Reference Manual, Rev. 1.10
246
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-10. RTI Frequency Divide Rates for RTDEC = 0
RTR[6:4] =
RTR[3:0]
1
000
(OFF)
001
(210)
010
(211)
011
(212)
100
(213)
101
(214)
110
(215)
111
(216)
0001 (÷2)
OFF
2x210
2x211
2x212
2x213
2x214
2x215
2x216
0010 (÷3)
OFF
3x210
3x211
3x212
3x213
3x214
3x215
3x216
0011 (÷4)
OFF
4x210
4x211
4x212
4x213
4x214
4x215
4x216
0100 (÷5)
OFF
5x210
5x211
5x212
5x213
5x214
5x215
5x216
0101 (÷6)
OFF
6x210
6x211
6x212
6x213
6x214
6x215
6x216
0110 (÷7)
OFF
7x210
7x211
7x212
7x213
7x214
7x215
7x216
0111 (÷8)
OFF
8x210
8x211
8x212
8x213
8x214
8x215
8x216
1000 (÷9)
OFF
9x210
9x211
9x212
9x213
9x214
9x215
9x216
1001 (÷10)
OFF
10x210
10x211
10x212
10x213
10x214
10x215
10x216
1010 (÷11)
OFF
11x210
11x211
11x212
11x213
11x214
11x215
11x216
1011 (÷12)
OFF
12x210
12x211
12x212
12x213
12x214
12x215
12x216
1100 (÷13)
OFF
13x210
13x211
13x212
13x213
13x214
13x215
13x216
1101 (÷14)
OFF
14x210
14x211
14x212
14x213
14x214
14x215
14x216
1110 (÷15)
OFF
15x210
15x211
15x212
15x213
15x214
15x215
15x216
1111 (÷16)
OFF
16x210
16x211
16x212
16x213
16x214
16x215
16x216
Denotes the default value out of reset.This value should be used to disable the RTI to ensure future backwards compatibility.
Table 8-11. RTI Frequency Divide Rates for RTDEC=1
RTR[6:4] =
RTR[3:0]
000
(1x103)
001
(2x103)
010
(5x103)
011
(10x103)
100
(20x103)
101
(50x103)
110
(100x103)
111
(200x103)
0000 (÷1)
1x103
2x103
5x103
10x103
20x103
50x103
100x103
200x103
0001 (÷2)
2x103
4x103
10x103
20x103
40x103
100x103
200x103
400x103
0010 (÷3)
3x103
6x103
15x103
30x103
60x103
150x103
300x103
600x103
0011 (÷4)
4x103
8x103
20x103
40x103
80x103
200x103
400x103
800x103
0100 (÷5)
5x103
10x103
25x103
50x103
100x103
250x103
500x103
1x106
0101 (÷6)
6x103
12x103
30x103
60x103
120x103
300x103
600x103
1.2x106
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
247
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-11. RTI Frequency Divide Rates for RTDEC=1
RTR[6:4] =
RTR[3:0]
000
(1x103)
001
(2x103)
010
(5x103)
011
(10x103)
100
(20x103)
101
(50x103)
110
(100x103)
111
(200x103)
0110 (÷7)
7x103
14x103
35x103
70x103
140x103
350x103
700x103
1.4x106
0111 (÷8)
8x103
16x103
40x103
80x103
160x103
400x103
800x103
1.6x106
1000 (÷9)
9x103
18x103
45x103
90x103
180x103
450x103
900x103
1.8x106
1001 (÷10)
10 x103
20x103
50x103
100x103
200x103
500x103
1x106
2x106
1010 (÷11)
11 x103
22x103
55x103
110x103
220x103
550x103
1.1x106
2.2x106
1011 (÷12)
12x103
24x103
60x103
120x103
240x103
600x103
1.2x106
2.4x106
1100 (÷13)
13x103
26x103
65x103
130x103
260x103
650x103
1.3x106
2.6x106
1101 (÷14)
14x103
28x103
70x103
140x103
280x103
700x103
1.4x106
2.8x106
1110 (÷15)
15x103
30x103
75x103
150x103
300x103
750x103
1.5x106
3x106
1111 (÷16)
16x103
32x103
80x103
160x103
320x103
800x103
1.6x106
3.2x106
8.3.2.9
S12XECRG COP Control Register (COPCTL)
This register controls the COP (Computer Operating Properly) watchdog.
Module Base + 0x0008
7
6
WCOP
RSBCK
R
W
Reset1
5
4
3
0
0
0
2
1
0
CR2
CR1
CR0
0
0
0
WRTMASK
0
0
0
0
0
1. Refer to Device User Guide (Section: S12XECRG) for reset values of WCOP, CR2, CR1 and CR0.
= Unimplemented or Reserved
Figure 8-11. S12XECRG COP Control Register (COPCTL)
Read: Anytime
Write:
1. RSBCK: anytime in special modes; write to “1” but not to “0” in all other modes
2. WCOP, CR2, CR1, CR0:
— Anytime in special modes
— Write once in all other modes
– Writing CR[2:0] to “000” has no effect, but counts for the “write once” condition.
– Writing WCOP to “0” has no effect, but counts for the “write once” condition.
S12XS Family Reference Manual, Rev. 1.10
248
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
The COP time-out period is restarted if one these two conditions is true:
1. Writing a non zero value to CR[2:0] (anytime in special modes, once in all other modes) with
WRTMASK = 0.
or
2. Changing RSBCK bit from “0” to “1”.
Table 8-12. COPCTL Field Descriptions
Field
Description
7
WCOP
Window COP Mode Bit — When set, a write to the ARMCOP register must occur in the last 25% of the selected
period. A write during the first 75% of the selected period will reset the part. As long as all writes occur during
this window, $55 can be written as often as desired. Once $AA is written after the $55, the time-out logic restarts
and the user must wait until the next window before writing to ARMCOP. Table 8-13 shows the duration of this
window for the seven available COP rates.
0 Normal COP operation
1 Window COP operation
6
RSBCK
COP and RTI Stop in Active BDM Mode Bit
0 Allows the COP and RTI to keep running in Active BDM mode.
1 Stops the COP and RTI counters whenever the part is in Active BDM mode.
5
Write Mask for WCOP and CR[2:0] Bit — This write-only bit serves as a mask for the WCOP and CR[2:0] bits
WRTMASK while writing the COPCTL register. It is intended for BDM writing the RSBCK without touching the contents of
WCOP and CR[2:0].
0 Write of WCOP and CR[2:0] has an effect with this write of COPCTL
1 Write of WCOP and CR[2:0] has no effect with this write of COPCTL.
(Does not count for “write once”.)
2–0
CR[2:0]
COP Watchdog Timer Rate Select — These bits select the COP time-out rate (see Table 8-13). Writing a
nonzero value to CR[2:0] enables the COP counter and starts the time-out period. A COP counter time-out
causes a system reset. This can be avoided by periodically (before time-out) reinitialize the COP counter via the
ARMCOP register.
While all of the following four conditions are true the CR[2:0], WCOP bits are ignored and the COP operates at
highest time-out period (2 24 cycles) in normal COP mode (Window COP mode disabled):
1) COP is enabled (CR[2:0] is not 000)
2) BDM mode active
3) RSBCK = 0
4) Operation in emulation or special modes
Table 8-13. COP Watchdog Rates1
CR2
CR1
CR0
OSCCLK
Cycles to Timeout
0
0
0
COP disabled
0
0
1
2 14
0
1
0
2 16
0
1
1
2 18
1
0
0
2 20
1
0
1
2 22
1
1
0
2 23
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
249
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-13. COP Watchdog Rates1
CR2
CR1
OSCCLK
Cycles to Timeout
CR0
1
1
1
2 24
1 OSCCLK cycles are referenced from the previous COP time-out reset
(writing $55/$AA to the ARMCOP register)
8.3.2.10
Reserved Register (FORBYP)
NOTE
This reserved register is designed for factory test purposes only, and is not
intended for general user access. Writing to this register when in special
modes can alter the S12XECRG’s functionality.
Module Base + 0x0009
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 8-12. Reserved Register (FORBYP)
Read: Always read $00 except in special modes
Write: Only in special modes
8.3.2.11
Reserved Register (CTCTL)
NOTE
This reserved register is designed for factory test purposes only, and is not
intended for general user access. Writing to this register when in special test
modes can alter the S12XECRG’s functionality.
Module Base + 0x000A
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 8-13. Reserved Register (CTCTL)
Read: Always read $00 except in special modes
S12XS Family Reference Manual, Rev. 1.10
250
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
Write: Only in special modes
8.3.2.12
S12XECRG COP Timer Arm/Reset Register (ARMCOP)
This register is used to restart the COP time-out period.
Module Base + 0x000B
7
6
5
4
3
2
1
0
R
0
0
0
0
0
0
0
0
W
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
0
0
0
0
0
0
Reset
Figure 8-14. S12XECRG ARMCOP Register Diagram
Read: Always reads $00
Write: Anytime
When the COP is disabled (CR[2:0] = “000”) writing to this register has no effect.
When the COP is enabled by setting CR[2:0] nonzero, the following applies:
Writing any value other than $55 or $AA causes a COP reset. To restart the COP time-out period
you must write $55 followed by a write of $AA. Other instructions may be executed between these
writes but the sequence ($55, $AA) must be completed prior to COP end of time-out period to
avoid a COP reset. Sequences of $55 writes or sequences of $AA writes are allowed. When the
WCOP bit is set, $55 and $AA writes must be done in the last 25% of the selected time-out period;
writing any value in the first 75% of the selected period will cause a COP reset.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
251
S12XE Clocks and Reset Generator (S12XECRGV1)
8.4
Functional Description
8.4.1
Functional Blocks
8.4.1.1
Phase Locked Loop with Internal Filter (IPLL)
The IPLL is used to run the MCU from a different time base than the incoming OSCCLK. Figure 8-15
shows a block diagram of the IPLL.
REFCLK
REFDIV[5:0]
EXTAL
REDUCED
CONSUMPTION
OSCILLATOR
OSCCLK
REFERENCE
PROGRAMMABLE
DIVIDER
XTAL
CLOCK
MONITOR
Supplied by:
FBCLK
LOCK
LOCK
DETECTOR
VDDPLL/VSSPLL
PDET
PHASE
DETECTOR
UP
CPUMP
AND
FILTER
DOWN
VCO
VCOCLK
LOOP
PROGRAMMABLE
DIVIDER
POST
PROGRAMMABLE
DIVIDER
PLLCLK
SYNDIV[5:0]
VDDPLL/VSSPLL
POSTDIV[4:0]
VDD/VSS
Figure 8-15. IPLL Functional Diagram
For increased flexibility, OSCCLK can be divided in a range of 1 to 64 to generate the reference frequency
REFCLK using the REFDIV[5:0] bits. This offers a finer multiplication granularity. Based on the
SYNDIV[5:0] bits the IPLL generates the VCOCLK by multiplying the reference clock by a multiple of 2,
4, 6,... 126, 128. Based on the POSTDIV[4:0] bits the VCOCLK can be divided in a range of 1,2,4,6,8,... to
62 to generate the PLLCLK.
.
SYNDIV + 1
f PLL = 2 × f OSC × -----------------------------------------------------------------------------[ REFDIV + 1 ] [ 2 × POSTDIV ]
NOTE
Although it is possible to set the dividers to command a very high clock
frequency, do not exceed the specified bus frequency limit for the MCU.
If (PLLSEL = 1) then fBUS = fPLL / 2.
IF POSTDIV = $00 the fPLL is identical to fVCO (divide by one)
Several examples of IPLL divider settings are shown in Table 8-14. Shaded rows indicated that these
settings are not recommended. The following rules help to achieve optimum stability and shortest lock
time:
• Use lowest possible fVCO / fREF ratio (SYNDIV value).
• Use highest possible REFCLK frequency fREF.
S12XS Family Reference Manual, Rev. 1.10
252
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-14. Examples of IPLL Divider Settings
fOSC
REFDIV[5:0]
fREF
4MHz
$01
2MHz
01
$18
100MHz
11
$00
100MHz 50 MHz
8MHz
$03
2MHz
01
$18
100MHz
11
$00
100MHz 50 MHz
4MHz
$00
4MHz
01
$09
80MHz
01
$00
80MHz
40MHz
8MHz
$00
8MHz
10
$04
80MHz
01
$00
80MHz
40MHz
4MHz
$00
4MHz
01
$03
32MHz
00
$01
16MHz
8MHz
4MHz
$01
2MHz
01
$18
100MHz
11
$01
50MHz
25MHz
4MHz
$03
1MHz
00
$18
50MHz
01
$00
50MHz
25MHz
4MHz
$03
1MHz
00
$31
100MHz
11
$01
50MHz
25MHz
8.4.1.1.1
REFFRQ[1:0] SYNDIV[5:0]
fVCO
VCOFRQ[1:0] POSTDIV[4:0]
fPLL
fBUS
IPLL Operation
The oscillator output clock signal (OSCCLK) is fed through the reference programmable divider and is
divided in a range of 1 to 64 (REFDIV+1) to output the REFCLK. The VCO output clock, (VCOCLK) is
fed back through the programmable loop divider and is divided in a range of 2 to 128 in increments of [2
x (SYNDIV +1)] to output the FBCLK. The VCOCLK is fed to the final programmable divider and is
divided in a range of 1,2,4,6,8,... to 62 (2*POSTDIV) to output the PLLCLK. See Figure 8-15.
The phase detector then compares the FBCLK, with the REFCLK. Correction pulses are generated based
on the phase difference between the two signals. The loop filter then slightly alters the DC voltage on the
internal filter capacitor, based on the width and direction of the correction pulse.
The user must select the range of the REFCLK frequency and the range of the VCOCLK frequency to
ensure that the correct IPLL loop bandwidth is set.
The lock detector compares the frequencies of the FBCLK, and the REFCLK. Therefore, the speed of the
lock detector is directly proportional to the reference clock frequency. The circuit determines the lock
condition based on this comparison.
If IPLL LOCK interrupt requests are enabled, the software can wait for an interrupt request and then check
the LOCK bit. If interrupt requests are disabled, software can poll the LOCK bit continuously (during IPLL
start-up, usually) or at periodic intervals. In either case, only when the LOCK bit is set, the PLLCLK can
be selected as the source for the system and core clocks. If the IPLL is selected as the source for the system
and core clocks and the LOCK bit is clear, the IPLL has suffered a severe noise hit and the software must
take appropriate action, depending on the application.
• The LOCK bit is a read-only indicator of the locked state of the IPLL.
• The LOCK bit is set when the VCO frequency is within a certain tolerance, ∆Lock, and is cleared
when the VCO frequency is out of a certain tolerance, ∆unl.
• Interrupt requests can occur if enabled (LOCKIE = 1) when the lock condition changes, toggling
the LOCK bit.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
253
S12XE Clocks and Reset Generator (S12XECRGV1)
8.4.1.2
System Clocks Generator
PLLSEL or SCM
PLLCLK
PHASE
LOCK
LOOP (IIPLL)
STOP
1
SYSCLK
÷2
SCM
EXTAL
1
OSCILLATOR
Core Clock
0
WAIT(RTIWAI),
STOP(PSTP, PRE),
RTI ENABLE
CLOCK PHASE
GENERATOR
Bus Clock
RTI
OSCCLK
0
WAIT(COPWAI),
STOP(PSTP, PCE),
COP ENABLE
XTAL
COP
Clock
Monitor
STOP
Oscillator
Clock
Gating
Condition
= Clock Gate
Figure 8-16. System Clocks Generator
The clock generator creates the clocks used in the MCU (see Figure 8-16). The gating condition placed on
top of the individual clock gates indicates the dependencies of different modes (STOP, WAIT) and the
setting of the respective configuration bits.
The peripheral modules use the Bus Clock. Some peripheral modules also use the Oscillator Clock. If the
MCU enters Self Clock Mode (see Section 8.4.2.2, “Self Clock Mode”) Oscillator clock source is switched
to PLLCLK running at its minimum frequency fSCM. The Bus Clock is used to generate the clock visible at
the ECLK pin. The Core Clock signal is the clock for the CPU. The Core Clock is twice the Bus Clock. But
note that a CPU cycle corresponds to one Bus Clock.
IPLL clock mode is selected with PLLSEL bit in the CLKSEL register. When selected, the IPLL output clock
drives SYSCLK for the main system including the CPU and peripherals. The IPLL cannot be turned off by
clearing the PLLON bit, if the IPLL clock is selected. When PLLSEL is changed, it takes a maximum of 4
OSCCLK plus 4 PLLCLK cycles to make the transition. During the transition, all clocks freeze and CPU
activity ceases.
S12XS Family Reference Manual, Rev. 1.10
254
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
8.4.1.3
Clock Monitor (CM)
If no OSCCLK edges are detected within a certain time, the clock monitor within the oscillator block
generates a clock monitor fail event. The S12XECRG then asserts self clock mode or generates a system
reset depending on the state of SCME bit. If the clock monitor is disabled or the presence of clocks is
detected no failure is indicated by the oscillator block.The clock monitor function is enabled/disabled by
the CME control bit.
8.4.1.4
Clock Quality Checker
The clock monitor performs a coarse check on the incoming clock signal. The clock quality checker
provides a more accurate check in addition to the clock monitor.
A clock quality check is triggered by any of the following events:
• Power on reset (POR)
• Low voltage reset (LVR)
• Wake-up from Full Stop Mode (exit full stop)
• Clock Monitor fail indication (CM fail)
A time window of 50000 PLLCLK cycles1 is called check window.
A number greater equal than 4096 rising OSCCLK edges within a check window is called osc ok. Note that
osc ok immediately terminates the current check window. See Figure 8-17 as an example.
CHECK WINDOW
1
3
2
49999
50000
PLLCLK
1
2
3
4
5
4096
OSCCLK
4095
OSC OK
Figure 8-17. Check Window Example
1.
IPLL is running at self clock mode frequency fSCM.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
255
S12XE Clocks and Reset Generator (S12XECRGV1)
The Sequence for clock quality check is shown in Figure 8-18.
CM FAIL
CLOCK OK
NO
EXIT FULL STOP
POR
LVR
SCME=1 &
FSTWKP=1
?
NO
YES
NUM = 0
FSTWKP = 0
?
ENTER SCM
YES
CLOCK MONITOR RESET
ENTER SCM
NUM = 50
YES
CHECK WINDOW
SCM
ACTIVE?
NUM = NUM-1
YES
OSC OK
?
NUM = 0
NO
NO
NUM > 0
?
YES
NO
SCME = 1
?
NO
YES
SCM
ACTIVE?
YES
SWITCH TO OSCCLK
NO
EXIT SCM
Figure 8-18. Sequence for Clock Quality Check
NOTE
Remember that in parallel to additional actions caused by Self Clock Mode
or Clock Monitor Reset1 handling the clock quality checker continues to
check the OSCCLK signal.
NOTE
The Clock Quality Checker enables the IPLL and the voltage regulator
(VREG) anytime a clock check has to be performed. An ongoing clock
quality check could also cause a running IPLL (fSCM) and an active VREG
during Pseudo Stop Mode.
1.
A Clock Monitor Reset will always set the SCME bit to logical’1’.
S12XS Family Reference Manual, Rev. 1.10
256
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
8.4.1.5
Computer Operating Properly Watchdog (COP)
The COP (free running watchdog timer) enables the user to check that a program is running and
sequencing properly. When the COP is being used, software is responsible for keeping the COP from
timing out. If the COP times out it is an indication that the software is no longer being executed in the
intended sequence; thus a system reset is initiated (see Section 8.4.1.5, “Computer Operating Properly
Watchdog (COP)”). The COP runs with a gated OSCCLK. Three control bits in the COPCTL register
allow selection of seven COP time-out periods.
When COP is enabled, the program must write $55 and $AA (in this order) to the ARMCOP register
during the selected time-out period. Once this is done, the COP time-out period is restarted. If the
program fails to do this and the COP times out, the part will reset. Also, if any value other than $55 or $AA
is written, the part is immediately reset.
Windowed COP operation is enabled by setting WCOP in the COPCTL register. In this mode, writes to
the ARMCOP register to clear the COP timer must occur in the last 25% of the selected time-out period.
A premature write will immediately reset the part.
If PCE bit is set, the COP will continue to run in Pseudo Stop Mode.
8.4.1.6
Real Time Interrupt (RTI)
The RTI can be used to generate a hardware interrupt at a fixed periodic rate. If enabled (by setting
RTIE=1), this interrupt will occur at the rate selected by the RTICTL register. The RTI runs with a gated
OSCCLK. At the end of the RTI time-out period the RTIF flag is set to one and a new RTI time-out period
starts immediately.
A write to the RTICTL register restarts the RTI time-out period.
If the PRE bit is set, the RTI will continue to run in Pseudo Stop Mode.
8.4.2
8.4.2.1
Operation Modes
Normal Mode
The S12XECRG block behaves as described within this specification in all normal modes.
8.4.2.2
Self Clock Mode
If the external clock frequency is not available due to a failure or due to long crystal start-up time, the Bus
Clock and the Core Clock are derived from the PLLCLK running at self clock mode frequency fSCM; this
mode of operation is called Self Clock Mode. This requires CME = 1 and SCME = 1, which is the default
after reset. If the MCU was clocked by the PLLCLK prior to entering Self Clock Mode, the PLLSEL bit will
be cleared. If the external clock signal has stabilized again, the S12XECRG will automatically select
OSCCLK to be the system clock and return to normal mode. See Section 8.4.1.4, “Clock Quality Checker”
for more information on entering and leaving Self Clock Mode.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
257
S12XE Clocks and Reset Generator (S12XECRGV1)
NOTE
In order to detect a potential clock loss the CME bit should always be
enabled (CME = 1).
If CME bit is disabled and the MCU is configured to run on PLLCLK, a loss
of external clock (OSCCLK) will not be detected and will cause the system
clock to drift towards lower frequencies. As soon as the external clock is
available again the system clock ramps up to its IPLL target frequency. If
the MCU is running on external clock any loss of clock will cause the
system to go static.
8.4.3
Low Power Options
This section summarizes the low power options available in the S12XECRG.
8.4.3.1
Run Mode
This is the default mode after reset.
The RTI can be stopped by setting the associated rate select bits to zero.
The COP can be stopped by setting the associated rate select bits to zero.
8.4.3.2
Wait Mode
The WAI instruction puts the MCU in a low power consumption stand-by mode depending on setting of
the individual bits in the CLKSEL register. All individual Wait Mode configuration bits can be superposed.
This provides enhanced granularity in reducing the level of power consumption during Wait Mode.
Table 8-15 lists the individual configuration bits and the parts of the MCU that are affected in Wait Mode.
Table 8-15. MCU Configuration During Wait Mode
PLLWAI
RTIWAI
COPWAI
IPLL
Stopped
—
—
RTI
—
Stopped
—
COP
—
—
Stopped
After executing the WAI instruction the core requests the S12XECRG to switch MCU into Wait Mode.
The S12XECRG then checks whether the PLLWAI bit is asserted. Depending on the configuration the
S12XECRG switches the system and core clocks to OSCCLK by clearing the PLLSEL bit and disables the
IPLL.
There are two ways to restart the MCU from Wait Mode:
1. Any reset
2. Any interrupt
S12XS Family Reference Manual, Rev. 1.10
258
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
8.4.3.3
Stop Mode
All clocks are stopped in STOP mode, dependent of the setting of the PCE, PRE and PSTP bit. The
oscillator is disabled in STOP mode unless the PSTP bit is set. If the PRE or PCE bits are set, the RTI or
COP continues to run in Pseudo Stop Mode. In addition to disabling system and core clocks the
S12XECRG requests other functional units of the MCU (e.g. voltage-regulator) to enter their individual
power saving modes (if available).
If the PLLSEL bit is still set when entering Stop Mode, the S12XECRG will switch the system and core
clocks to OSCCLK by clearing the PLLSEL bit. Then the S12XECRG disables the IPLL, disables the core
clock and finally disables the remaining system clocks.
If Pseudo Stop Mode is entered from Self-Clock Mode the S12XECRG will continue to check the clock
quality until clock check is successful. In this case the IPLL and the voltage regulator (VREG) will remain
enabled. If Full Stop Mode (PSTP = 0) is entered from Self-Clock Mode the ongoing clock quality check
will be stopped. A complete timeout window check will be started when Stop Mode is left again.
There are two ways to restart the MCU from Stop Mode:
1. Any reset
2. Any interrupt
If the MCU is woken-up from Full Stop Mode by an interrupt and the fast wake-up feature is enabled
(FSTWKP=1 and SCME=1), the system will immediately (no clock quality check) resume operation in
Self-Clock Mode (see Section 8.4.1.4, “Clock Quality Checker”). The SCMIF flag will not be set for this
special case. The system will remain in Self-Clock Mode with oscillator disabled until FSTWKP bit is
cleared. The clearing of FSTWKP will start the oscillator and the clock quality check. If the clock quality
check is successful, the S12XECRG will switch all system clocks to oscillator clock. The SCMIF flag will be
set. See application examples in Figure 8-19 and Figure 8-20.
Because the IPLL has been powered-down during Stop Mode the PLLSEL bit is cleared and the MCU runs
on OSCCLK after leaving Stop-Mode. The software must manually set the PLLSEL bit again, in order to
switch system and core clocks to the PLLCLK.
NOTE
In Full Stop Mode or Self-Clock Mode caused by the fast wake-up feature
the clock monitor and the oscillator are disabled.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
259
S12XE Clocks and Reset Generator (S12XECRGV1)
CPU resumes program execution immediately
Instruction
STOP
STOP
FSTWKP=1 SCME=1
STOP
Interrupt
IRQ service
IRQ service
IRQ service
Interrupt
Interrupt
Power Saving
Oscillator Clock
Oscillator Disabled
PLL Clock
Core Clock
Self-Clock Mode
Figure 8-19. Fast Wake-up from Full Stop Mode: Example 1
.
CPU resumes program execution immediately
Instruction
Frequent Uncritical
Frequent Critical
Instructions
Instructions Possible
IRQ Service
STOP
FSTWKP=1 SCME=1
IRQ Interrupt FSTWKP=0 SCMIE=1
SCM Interrupt
Clock Quality Check
Oscillator Clock
Oscillator Disabled Osc Startup
PLL Clock
Self-Clock Mode
Core Clock
Figure 8-20. Fast Wake-up from Full Stop Mode: Example 2
8.5
Resets
All reset sources are listed in Table 8-16. Refer to MCU specification for related vector addresses and
priorities.
Table 8-16. Reset Summary
Reset Source
Local Enable
Power on Reset
None
Low Voltage Reset
None
External Reset
None
Illegal Address Reset
None
Clock Monitor Reset
PLLCTL (CME=1, SCME=0)
S12XS Family Reference Manual, Rev. 1.10
260
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
Table 8-16. Reset Summary
8.5.1
Reset Source
Local Enable
COP Watchdog Reset
COPCTL (CR[2:0] nonzero)
Description of Reset Operation
The reset sequence is initiated by any of the following events:
• Low level is detected at the RESET pin (External Reset).
• Power on is detected.
• Low voltage is detected.
• Illegal Address Reset is detected (see S12XMMC Block Guide for details).
• COP watchdog times out.
• Clock monitor failure is detected and Self-Clock Mode was disabled (SCME=0).
Upon detection of any reset event, an internal circuit drives the RESET pin low for 128 SYSCLK cycles (see
Figure 8-21). Since entry into reset is asynchronous it does not require a running SYSCLK. However, the
internal reset circuit of the S12XECRG cannot sequence out of current reset condition without a running
SYSCLK. The number of 128 SYSCLK cycles might be increased by n = 3 to 6 additional SYSCLK cycles
depending on the internal synchronization latency. After 128+n SYSCLK cycles the RESET pin is released.
The reset generator of the S12XECRG waits for additional 64 SYSCLK cycles and then samples the RESET
pin to determine the originating source. Table 8-17 shows which vector will be fetched.
Table 8-17. Reset Vector Selection
Sampled RESET Pin
Clock Monitor
COP
(64 cycles after release) Reset Pending Reset Pending
Vector Fetch
1
0
0
POR / LVR /
Illegal Address Reset/
External Reset
1
1
X
Clock Monitor Reset
1
0
1
COP Reset
0
X
X
POR / LVR /
Illegal Address Reset/ External Reset
with rise of RESET pin
NOTE
External circuitry connected to the RESET pin should be able to raise the
signal to a valid logic one within 64 SYSCLK cycles after the low drive is
released by the MCU. If this requirement is not adhered to the reset source
will always be recognized as “External Reset” even if the reset was initially
caused by an other reset source.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
261
S12XE Clocks and Reset Generator (S12XECRGV1)
The internal reset of the MCU remains asserted while the reset generator completes the 192 SYSCLK long
reset sequence. In case the RESET pin is externally driven low for more than these 192 SYSCLK cycles
(External Reset), the internal reset remains asserted longer.
Figure 8-21. RESET Timing
RESET
)(
)(
ICRG drives RESET pin low
)
)
SYSCLK
possibly
SYSCLK
not
running
)
(
(
128+n cycles
8.5.1.1
RESET pin
released
(
64 cycles
with n being
min 3 / max 6
cycles depending
on internal
synchronization
delay
possibly
RESET
driven low
externally
Clock Monitor Reset
The S12XECRG generates a Clock Monitor Reset in case all of the following conditions are true:
• Clock monitor is enabled (CME = 1)
• Loss of clock is detected
• Self-Clock Mode is disabled (SCME = 0).
The reset event asynchronously forces the configuration registers to their default settings. In detail the
CME and the SCME are reset to logical ‘1’ (which changes the state of the SCME bit. As a consequence the
S12XECRG immediately enters Self Clock Mode and starts its internal reset sequence. In parallel the clock
quality check starts. As soon as clock quality check indicates a valid Oscillator Clock the S12XECRG
switches to OSCCLK and leaves Self Clock Mode. Since the clock quality checker is running in parallel to
the reset generator, the S12XECRG may leave Self Clock Mode while still completing the internal reset
sequence.
8.5.1.2
Computer Operating Properly Watchdog (COP) Reset
When COP is enabled, the S12XECRG expects sequential write of $55 and $AA (in this order) to the
ARMCOP register during the selected time-out period. Once this is done, the COP time-out period
restarts. If the program fails to do this the S12XECRG will generate a reset.
8.5.1.3
Power On Reset, Low Voltage Reset
The on-chip voltage regulator detects when VDD to the MCU has reached a certain level and asserts power
on reset or low voltage reset or both. As soon as a power on reset or low voltage reset is triggered the
S12XS Family Reference Manual, Rev. 1.10
262
Freescale Semiconductor
S12XE Clocks and Reset Generator (S12XECRGV1)
S12XECRG performs a quality check on the incoming clock signal. As soon as clock quality check indicates
a valid Oscillator Clock signal the reset sequence starts using the Oscillator clock. If after 50 check windows
the clock quality check indicated a non-valid Oscillator Clock the reset sequence starts using Self-Clock
Mode.
Figure 8-22 and Figure 8-23 show the power-up sequence for cases when the RESET pin is tied to VDD and
when the RESET pin is held low.
Clock Quality Check
(no Self-Clock Mode)
RESET
)(
Internal POR
)(
128 SYSCLK
Internal RESET
64 SYSCLK
)(
Figure 8-22. RESET Pin Tied to VDD (by a Pull-up Resistor)
Clock Quality Check
(no Self Clock Mode)
)(
RESET
Internal POR
)(
128 SYSCLK
Internal RESET
)(
64 SYSCLK
Figure 8-23. RESET Pin Held Low Externally
8.6
Interrupts
The interrupts/reset vectors requested by the S12XECRG are listed in Table 8-18. Refer to MCU
specification for related vector addresses and priorities.
Table 8-18. S12XECRG Interrupt Vectors
Interrupt Source
CCR
Mask
Local Enable
Real time interrupt
I bit
CRGINT (RTIE)
LOCK interrupt
I bit
CRGINT (LOCKIE)
SCM interrupt
I bit
CRGINT (SCMIE)
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
263
S12XE Clocks and Reset Generator (S12XECRGV1)
8.6.1
8.6.1.1
Description of Interrupt Operation
Real Time Interrupt
The S12XECRG generates a real time interrupt when the selected interrupt time period elapses. RTI
interrupts are locally disabled by setting the RTIE bit to zero. The real time interrupt flag (RTIF) is set to1
when a timeout occurs, and is cleared to 0 by writing a 1 to the RTIF bit.
The RTI continues to run during Pseudo Stop Mode if the PRE bit is set to 1. This feature can be used for
periodic wakeup from Pseudo Stop if the RTI interrupt is enabled.
8.6.1.2
IPLL Lock Interrupt
The S12XECRG generates a IPLL Lock interrupt when the LOCK condition of the IPLL has changed,
either from a locked state to an unlocked state or vice versa. Lock interrupts are locally disabled by setting
the LOCKIE bit to zero. The IPLL Lock interrupt flag (LOCKIF) is set to1 when the LOCK condition has
changed, and is cleared to 0 by writing a 1 to the LOCKIF bit.
8.6.1.3
Self Clock Mode Interrupt
The S12XECRG generates a Self Clock Mode interrupt when the SCM condition of the system has
changed, either entered or exited Self Clock Mode. SCM conditions are caused by a failing clock quality
check after power on reset (POR) or low voltage reset (LVR) or recovery from Full Stop Mode (PSTP = 0)
or Clock Monitor failure. For details on the clock quality check refer to Section 8.4.1.4, “Clock Quality
Checker”. If the clock monitor is enabled (CME = 1) a loss of external clock will also cause a SCM
condition (SCME = 1).
SCM interrupts are locally disabled by setting the SCMIE bit to zero. The SCM interrupt flag (SCMIF) is
set to1 when the SCM condition has changed, and is cleared to 0 by writing a 1 to the SCMIF bit.
S12XS Family Reference Manual, Rev. 1.10
264
Freescale Semiconductor
Chapter 9
Pierce Oscillator (S12XOSCLCPV2)
Table 9-1. Revision History
Revision
Number
Revision
Date
Sections
Affected
Description of Changes
V01.05
19 Jul 2006
- All xclks info was removed
V02.00
04 Aug 2006
- Incremented revision to match the design system spec revision
9.1
Introduction
The Pierce oscillator (XOSC) module provides a robust, low-noise and low-power clock source. The
module will be operated from the VDDPLL supply rail (1.8 V nominal) and require the minimum number
of external components. It is designed for optimal start-up margin with typical crystal oscillators.
9.1.1
Features
The XOSC will contain circuitry to dynamically control current gain in the output amplitude. This ensures
a signal with low harmonic distortion, low power and good noise immunity.
• High noise immunity due to input hysteresis
• Low RF emissions with peak-to-peak swing limited dynamically
• Transconductance (gm) sized for optimum start-up margin for typical oscillators
• Dynamic gain control eliminates the need for external current limiting resistor
• Integrated resistor eliminates the need for external bias resistor in loop controlled Pierce mode.
• Low power consumption:
— Operates from 1.8 V (nominal) supply
— Amplitude control limits power
• Clock monitor
9.1.2
Modes of Operation
Two modes of operation exist:
1. Loop controlled Pierce (LCP) oscillator
2. External square wave mode featuring also full swing Pierce (FSP) without internal bias resistor
The oscillator mode selection is described in the Device Overview section, subsection Oscillator
Configuration.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
265
Pierce Oscillator (S12XOSCLCPV2)
9.1.3
Block Diagram
Figure 9-1 shows a block diagram of the XOSC.
Monitor_Failure
Clock
Monitor
OSCCLK
Peak
Detector
Gain Control
VDDPLL = 1.8 V
Rf
XTAL
EXTAL
Figure 9-1. XOSC Block Diagram
9.2
External Signal Description
This section lists and describes the signals that connect off chip
9.2.1
VDDPLL and VSSPLL — Operating and Ground Voltage Pins
Theses pins provides operating voltage (VDDPLL) and ground (VSSPLL) for the XOSC circuitry. This
allows the supply voltage to the XOSC to use an independent bypass capacitor.
9.2.2
EXTAL and XTAL — Input and Output Pins
These pins provide the interface for either a crystal or a 1.8V CMOS compatible clock to control the
internal clock generator circuitry. EXTAL is the external clock input or the input to the crystal oscillator
amplifier. XTAL is the output of the crystal oscillator amplifier. The MCU internal system clock is derived
S12XS Family Reference Manual, Rev. 1.10
266
Freescale Semiconductor
Pierce Oscillator (S12XOSCLCPV2)
from the EXTAL input frequency. In full stop mode (PSTP = 0), the EXTAL pin is pulled down by an
internal resistor of typical 200 kΩ.
NOTE
Freescale recommends an evaluation of the application board and chosen
resonator or crystal by the resonator or crystal supplier.
Loop controlled circuit is not suited for overtone resonators and crystals.
EXTAL
C1
MCU
Crystal or
Ceramic Resonator
XTAL
C2
VSSPLL
Figure 9-2. Loop Controlled Pierce Oscillator Connections (LCP mode selected)
NOTE
Full swing Pierce circuit is not suited for overtone resonators and crystals
without a careful component selection.
EXTAL
C1
MCU
RB
Crystal or
Ceramic Resonator
RS*
XTAL
C2
VSSPLL
* Rs can be zero (shorted) when use with higher frequency crystals.
Refer to manufacturer’s data.
Figure 9-3. Full Swing Pierce Oscillator Connections (FSP mode selected)
EXTAL
CMOS Compatible
External Oscillator
(VDDPLL Level)
MCU
XTAL
Not Connected
Figure 9-4. External Clock Connections (FSP mode selected)
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
267
Pierce Oscillator (S12XOSCLCPV2)
9.3
Memory Map and Register Definition
The CRG contains the registers and associated bits for controlling and monitoring the oscillator module.
9.4
Functional Description
The XOSC module has control circuitry to maintain the crystal oscillator circuit voltage level to an optimal
level which is determined by the amount of hysteresis being used and the maximum oscillation range.
The oscillator block has two external pins, EXTAL and XTAL. The oscillator input pin, EXTAL, is
intended to be connected to either a crystal or an external clock source. The XTAL pin is an output signal
that provides crystal circuit feedback.
A buffered EXTAL signal becomes the internal clock. To improve noise immunity, the oscillator is
powered by the VDDPLL and VSSPLL power supply pins.
9.4.1
Gain Control
In LCP mode a closed loop control system will be utilized whereby the amplifier is modulated to keep the
output waveform sinusoidal and to limit the oscillation amplitude. The output peak to peak voltage will be
kept above twice the maximum hysteresis level of the input buffer. Electrical specification details are
provided in the Electrical Characteristics appendix.
9.4.2
Clock Monitor
The clock monitor circuit is based on an internal RC time delay so that it can operate without any MCU
clocks. If no OSCCLK edges are detected within this RC time delay, the clock monitor indicates failure
which asserts self-clock mode or generates a system reset depending on the state of SCME bit. If the clock
monitor is disabled or the presence of clocks is detected no failure is indicated.The clock monitor function
is enabled/disabled by the CME control bit, described in the CRG block description chapter.
9.4.3
Wait Mode Operation
During wait mode, XOSC is not impacted.
9.4.4
Stop Mode Operation
XOSC is placed in a static state when the part is in stop mode except when pseudo-stop mode is enabled.
During pseudo-stop mode, XOSC is not impacted.
S12XS Family Reference Manual, Rev. 1.10
268
Freescale Semiconductor
Chapter 10
Analog-to-Digital Converter (ADC12B16CV1)
Revision History
Version
Number
Revision
Date
Effective
Date
V01.00
13 Oct. 2005
13 Oct. 2005
Initial version
V01.01
4 Mar. 2008
4 Mar. 2008
correchted reference that DJM bit is in ATDCTL3
10.1
Author
Description of Changes
Introduction
The ADC12B16C is a 16-channel, 12-bit, multiplexed input successive approximation analog-to-digital
converter. Refer to device electrical specifications for ATD accuracy.
10.1.1
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Features
8-, 10-, or 12-bit resolution.
Conversion in Stop Mode using internally generated clock
Automatic return to low power after conversion sequence
Automatic compare with interrupt for higher than or less/equal than programmable value
Programmable sample time.
Left/right justified result data.
External trigger control.
Sequence complete interrupt.
Analog input multiplexer for 16 analog input channels.
Special conversions for VRH, VRL, (VRL+VRH)/2.
1-to-16 conversion sequence lengths.
Continuous conversion mode.
Multiple channel scans.
Configurable external trigger functionality on any AD channel or any of four additional trigger
inputs. The four additional trigger inputs can be chip external or internal. Refer to device
specification for availability and connectivity.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
269
Analog-to-Digital Converter (ADC12B16CV1)
•
Configurable location for channel wrap around (when converting multiple channels in a sequence).
S12XS Family Reference Manual, Rev. 1.10
270
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
10.1.2
10.1.2.1
Modes of Operation
Conversion Modes
There is software programmable selection between performing single or continuous conversion on a
single channel or multiple channels.
10.1.2.2
•
•
•
MCU Operating Modes
Stop Mode
— ICLKSTP=0 (in ATDCTL2 register)
Entering Stop Mode aborts any conversion sequence in progress and if a sequence was aborted
restarts it after exiting stop mode. This has the same effect/consequences as starting a
conversion sequence with write to ATDCTL5. So after exiting from stop mode with a
previously aborted sequence all flags are cleared etc.
— ICLKSTP=1 (in ATDCTL2 register)
A/D conversion sequence seamless continues in Stop Mode based on the internally generated
clock ICLK as ATD clock. For conversions during transition from Run to Stop Mode or vice
versa the result is not written to the results register, no CCF flag is set and no compare is done.
When converting in Stop Mode (ICLKSTP=1) an ATD Stop Recovery time tATDSTPRCV is
required to switch back to bus clock based ATDCLK when leaving Stop Mode. Do not access
ATD registers during this time.
Wait Mode
ADC12B16C behaves same in Run and Wait Mode. For reduced power consumption continuos
conversions should be aborted before entering Wait mode.
Freeze Mode
In Freeze Mode the ADC12B16C will either continue or finish or stop converting according to the
FRZ1 and FRZ0 bits. This is useful for debugging and emulation.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
271
Analog-to-Digital Converter (ADC12B16CV1)
10.1.3
Block Diagram
Bus Clock
ICLK
Clock
Prescaler
Internal
Clock
ATD Clock
ETRIG0
ETRIG1
ETRIG2
Trigger
Mux
Mode and
ATD_12B16C
Sequence Complete
Interrupt
Compare Interrupt
Timing Control
ETRIG3
(See device specification for availability
and connectivity)
ATDCTL1
ATDDIEN
VDDA
VSSA
Successive
Approximation
Register (SAR)
and DAC
VRH
VRL
AN15
AN14
AN13
Results
ATD 0
ATD 1
ATD 2
ATD 3
ATD 4
ATD 5
ATD 6
ATD 7
ATD 8
ATD 9
ATD 10
ATD 11
ATD 12
ATD 13
ATD 14
ATD 15
AN12
AN11
+
AN10
Sample & Hold
AN9
-
AN8
AN7
Analog
MUX
Comparator
AN6
AN5
AN4
AN3
AN2
AN1
AN0
Figure 10-1. ADC12B16C Block Diagram
S12XS Family Reference Manual, Rev. 1.10
272
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
10.2
Signal Description
This section lists all inputs to the ADC12B16C block.
10.2.1
Detailed Signal Descriptions
10.2.1.1
ANx (x = 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
This pin serves as the analog input Channel x. It can also be configured as digital port or external trigger
for the ATD conversion.
10.2.1.2
ETRIG3, ETRIG2, ETRIG1, ETRIG0
These inputs can be configured to serve as an external trigger for the ATD conversion.
Refer to device specification for availability and connection of these inputs!
10.2.1.3
VRH, VRL
VRH is the high reference voltage, VRL is the low reference voltage for ATD conversion.
10.2.1.4
VDDA, VSSA
These pins are the power supplies for the analog circuitry of the ADC12B16C block.
10.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the ADC12B16C.
10.3.1
Module Memory Map
Figure 10-2 gives an overview on all ADC12B16C registers.
NOTE
Register Address = Base Address + Address Offset, where the Base Address
is defined at the MCU level and the Address Offset is defined at the module
level.
Address
Name
0x0000
ATDCTL0
0x0001
ATDCTL1
0x0002
ATDCTL2
Bit 7
R
Reserved
W
R
ETRIGSEL
W
R
0
W
6
0
5
0
SRES1
SRES0
AFFC
4
0
3
2
1
Bit 0
WRAP3
WRAP2
WRAP1
WRAP0
SMP_DIS ETRIGCH3 ETRIGCH2 ETRIGCH1 ETRIGCH0
ICLKSTP ETRIGLE
ETRIGP
ETRIGE
ASCIE
ACMPIE
= Unimplemented or Reserved
Figure 10-2. ADC12B16C Register Summary (Sheet 1 of 3)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
273
Analog-to-Digital Converter (ADC12B16CV1)
Address
Name
0x0003
ATDCTL3
0x0004
ATDCTL4
0x0005
ATDCTL5
0x0006
ATDSTAT0
0x0007
Unimplemented
0x0008
ATDCMPEH
0x0009
ATDCMPEL
0x000A
ATDSTAT2H
0x000B
ATDSTAT2L
0x000C
ATDDIENH
0x000D
ATDDIENL
0x000E ATDCMPHTH
0x000F ATDCMPHTL
0x0010
ATDDR0
0x0012
ATDDR1
0x0014
ATDDR2
0x0016
ATDDR3
0x0018
ATDDR4
0x001A
ATDDR5
0x001C
ATDDR6
0x001E
ATDDR7
0x0020
ATDDR8
0x0022
ATDDR9
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
Bit 7
6
5
4
3
2
1
Bit 0
DJM
S8C
S4C
S2C
S1C
FIFO
FRZ1
FRZ0
SMP2
SMP1
SMP0
SC
SCAN
MULT
ETORF
FIFOR
0
0
0
SCF
0
0
0
PRS[4:0]
CD
CC
CB
CA
CC3
CC2
CC1
CC0
0
0
0
0
CMPE[15:8]
CMPE[7:0]
CCF[15:8]
CCF[7:0]
IEN[15:8]
IEN[7:0]
CMPHT[15:8]
CMPHT[7:0]
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
= Unimplemented or Reserved
Figure 10-2. ADC12B16C Register Summary (Sheet 2 of 3)
S12XS Family Reference Manual, Rev. 1.10
274
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
Address
Name
0x0024
ATDDR10
0x0026
ATDDR11
0x0028
ATDDR12
0x002A
ATDDR13
0x002C
ATDDR14
0x002E
ATDDR15
Bit 7
R
W
R
W
R
W
R
W
R
W
R
W
6
5
4
3
2
1
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
Bit 0
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
See Section 10.3.2.12.1, “Left Justified Result Data (DJM=0)”
and Section 10.3.2.12.2, “Right Justified Result Data (DJM=1)”
= Unimplemented or Reserved
Figure 10-2. ADC12B16C Register Summary (Sheet 3 of 3)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
275
Analog-to-Digital Converter (ADC12B16CV1)
10.3.2
Register Descriptions
This section describes in address order all the ADC12B16C registers and their individual bits.
10.3.2.1
ATD Control Register 0 (ATDCTL0)
Writes to this register will abort current conversion sequence.
Module Base + 0x0000
7
R
W
Reserved
Reset
0
6
5
4
0
0
0
0
0
0
3
2
1
0
WRAP3
WRAP2
WRAP1
WRAP0
1
1
1
1
= Unimplemented or Reserved
Figure 10-3. ATD Control Register 0 (ATDCTL0)
Read: Anytime
Write: Anytime, in special modes always write 0 to Reserved Bit 7.
Table 10-1. ATDCTL0 Field Descriptions
Field
3-0
WRAP[3-0]
Description
Wrap Around Channel Select Bits — These bits determine the channel for wrap around when doing multichannel conversions. The coding is summarized in Table 10-2.
Table 10-2. Multi-Channel Wrap Around Coding
WRAP3 WRAP2 WRAP1 WRAP0
Multiple Channel Conversions (MULT = 1)
Wraparound to AN0 after Converting
0
0
0
0
Reserved1
0
0
0
1
AN1
0
0
1
0
AN2
0
0
1
1
AN3
0
1
0
0
AN4
0
1
0
1
AN5
0
1
1
0
AN6
0
1
1
1
AN7
1
0
0
0
AN8
1
0
0
1
AN9
1
0
1
0
AN10
1
0
1
1
AN11
1
1
0
0
AN12
1
1
0
1
AN13
1
1
1
0
AN14
1
1
1
1
AN15
S12XS Family Reference Manual, Rev. 1.10
276
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
1If
10.3.2.2
only AN0 should be converted use MULT=0.
ATD Control Register 1 (ATDCTL1)
Writes to this register will abort current conversion sequence.
Module Base + 0x0001
7
6
5
4
3
2
1
0
ETRIGSEL
SRES1
SRES0
SMP_DIS
ETRIGCH3
ETRIGCH2
ETRIGCH1
ETRIGCH0
0
0
1
0
1
1
1
1
R
W
Reset
Figure 10-4. ATD Control Register 1 (ATDCTL1)
Read: Anytime
Write: Anytime
Table 10-3. ATDCTL1 Field Descriptions
Field
Description
7
ETRIGSEL
External Trigger Source Select — This bit selects the external trigger source to be either one of the AD
channels or one of the ETRIG3-0 inputs. See device specification for availability and connectivity of ETRIG30 inputs. If a particular ETRIG3-0 input option is not available, writing a 1 to ETRISEL only sets the bit but has
not effect, this means that one of the AD channels (selected by ETRIGCH3-0) is configured as the source for
external trigger. The coding is summarized in Table 10-5.
6–5
SRES[1:0]
A/D Resolution Select — These bits select the resolution of A/D conversion results. See Table 10-4 for
coding.
4
SMP_DIS
Discharge Before Sampling Bit
0 No discharge before sampling.
1 The internal sample capacitor is discharged before sampling the channel. This adds 2 ATD clock cycles to
the sampling time. This can help to detect an open circuit instead of measuring the previous sampled
channel.
3–0
External Trigger Channel Select — These bits select one of the AD channels or one of the ETRIG3-0 inputs
ETRIGCH[3:0] as source for the external trigger. The coding is summarized in Table 10-5.
Table 10-4. A/D Resolution Coding
SRES1
SRES0
A/D Resolution
0
0
8-bit data
0
1
10-bit data
1
0
12-bit data
1
1
Reserved
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
277
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-5. External Trigger Channel Select Coding
1
ETRIGSEL
ETRIGCH3
ETRIGCH2
ETRIGCH1
ETRIGCH0
External trigger source is
0
0
0
0
0
AN0
0
0
0
0
1
AN1
0
0
0
1
0
AN2
0
0
0
1
1
AN3
0
0
1
0
0
AN4
0
0
1
0
1
AN5
0
0
1
1
0
AN6
0
0
1
1
1
AN7
0
1
0
0
0
AN8
0
1
0
0
1
AN9
0
1
0
1
0
AN10
0
1
0
1
1
AN11
0
1
1
0
0
AN12
0
1
1
0
1
AN13
0
1
1
1
0
AN14
0
1
1
1
1
AN15
1
0
0
0
0
ETRIG01
1
0
0
0
1
ETRIG11
1
0
0
1
0
ETRIG21
1
0
0
1
1
ETRIG31
1
0
1
X
X
Reserved
1
1
X
X
X
Reserved
Only if ETRIG3-0 input option is available (see device specification), else ETRISEL is ignored, that means
external trigger source is still on one of the AD channels selected by ETRIGCH3-0
10.3.2.3
ATD Control Register 2 (ATDCTL2)
Writes to this register will abort current conversion sequence.
Module Base + 0x0002
7
R
6
5
4
3
2
1
0
AFFC
ICLKSTP
ETRIGLE
ETRIGP
ETRIGE
ASCIE
ACMPIE
0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 10-5. ATD Control Register 2 (ATDCTL2)
Read: Anytime
Write: Anytime
S12XS Family Reference Manual, Rev. 1.10
278
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-6. ATDCTL2 Field Descriptions
Field
Description
6
AFFC
ATD Fast Flag Clear All
0 ATD flag clearing done by write 1 to respective CCF[n] flag.
1 Changes all ATD conversion complete flags to a fast clear sequence.
For compare disabled (CMPE[n]=0) a read access to the result register will cause the associated CCF[n] flag
to clear automatically.
For compare enabled (CMPE[n]=1) a write access to the result register will cause the associated CCF[n] flag
to clear automatically.
5
ICLKSTP
Internal Clock in Stop Mode Bit — This bit enables A/D conversions in stop mode. When going into stop mode
and ICLKSTP=1 the ATD conversion clock is automatically switched to the internally generated clock ICLK.
Current conversion sequence will seamless continue. Conversion speed will change from prescaled bus
frequency to the ICLK frequency (see ATD Electrical Characteristics in device description). The prescaler bits
PRS4-0 in ATDCTL4 have no effect on the ICLK frequency. For conversions during stop mode the automatic
compare interrupt or the sequence complete interrupt can be used to inform software handler about changing
A/D values. External trigger will not work while converting in stop mode. For conversions during transition from
Run to Stop Mode or vice versa the result is not written to the results register, no CCF flag is set and no compare
is done. When converting in Stop Mode (ICLKSTP=1) an ATD Stop Recovery time tATDSTPRCV is required to
switch back to bus clock based ATDCLK when leaving Stop Mode. Do not access ATD registers during this time.
0 If A/D conversion sequence is ongoing when going into stop mode, the actual conversion sequence will be
aborted and automatically restarted when exiting stop mode.
1 A/D continues to convert in stop mode using internally generated clock (ICLK)
4
ETRIGLE
External Trigger Level/Edge Control — This bit controls the sensitivity of the external trigger signal. See
Table 10-7 for details.
3
ETRIGP
External Trigger Polarity — This bit controls the polarity of the external trigger signal. See Table 10-7 for details.
2
ETRIGE
External Trigger Mode Enable — This bit enables the external trigger on one of the AD channels or one of the
ETRIG3-0 inputs as described in Table 10-5. If external trigger source is one of the AD channels, the digital input
buffer of this channel is enabled. The external trigger allows to synchronize the start of conversion with external
events. External trigger will not work while converting in stop mode.
0 Disable external trigger
1 Enable external trigger
1
ASCIE
0
ACMPIE
ATD Sequence Complete Interrupt Enable
0 ATD Sequence Complete interrupt requests are disabled.
1 ATD Sequence Complete interrupt will be requested whenever SCF=1 is set.
ATD Compare Interrupt Enable — If automatic compare is enabled for conversion n (CMPE[n]=1 in ATDCMPE
register) this bit enables the compare interrupt. If the CCF[n] flag is set (showing a successful compare for
conversion n), the compare interrupt is triggered.
0 ATD Compare interrupt requests are disabled.
1 For the conversions in a sequence for which automatic compare is enabled (CMPE[n]=1), ATD Compare
Interrupt will be requested whenever any of the respective CCF flags is set.
Table 10-7. External Trigger Configurations
ETRIGLE
ETRIGP
External Trigger Sensitivity
0
0
Falling edge
0
1
Rising edge
1
0
Low level
1
1
High level
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
279
Analog-to-Digital Converter (ADC12B16CV1)
10.3.2.4
ATD Control Register 3 (ATDCTL3)
Writes to this register will abort current conversion sequence.
Module Base + 0x0003
7
6
5
4
3
2
1
0
DJM
S8C
S4C
S2C
S1C
FIFO
FRZ1
FRZ0
0
0
1
0
0
0
0
0
R
W
Reset
= Unimplemented or Reserved
Figure 10-6. ATD Control Register 3 (ATDCTL3)
Read: Anytime
Write: Anytime
Table 10-8. ATDCTL3 Field Descriptions
Field
Description
7
DJM
Result Register Data Justification — Result data format is always unsigned. This bit controls justification of
conversion data in the result registers.
0 Left justified data in the result registers.
1 Right justified data in the result registers.
Table 10-9 gives examples ATD results for an input signal range between 0 and 5.12 Volts.
6–3
S8C, S4C,
S2C, S1C
Conversion Sequence Length — These bits control the number of conversions per sequence. Table 10-10
shows all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity
to HC12 family.
2
FIFO
Result Register FIFO Mode — If this bit is zero (non-FIFO mode), the A/D conversion results map into the result
registers based on the conversion sequence; the result of the first conversion appears in the first result register
(ATDDR0), the second result in the second result register (ATDDR1), and so on.
If this bit is one (FIFO mode) the conversion counter is not reset at the beginning or ending of a conversion
sequence; sequential conversion results are placed in consecutive result registers. In a continuously scanning
conversion sequence, the result register counter will wrap around when it reaches the end of the result register
file. The conversion counter value (CC3-0 in ATDSTAT0) can be used to determine where in the result register
file, the current conversion result will be placed.
Aborting a conversion or starting a new conversion clears the conversion counter even if FIFO=1. So the first
result of a new conversion sequence, started by writing to ATDCTL5, will always be place in the first result register
(ATDDDR0). Intended usage of FIFO mode is continuos conversion (SCAN=1) or triggered conversion
(ETRIG=1).
Which result registers hold valid data can be tracked using the conversion complete flags. Fast flag clear mode
may or may not be useful in a particular application to track valid data.
If this bit is one, automatic compare of result registers is always disabled, that is ADC12B16C will behave as if
ACMPIE and all CPME[n] were zero.
0 Conversion results are placed in the corresponding result register up to the selected sequence length.
1 Conversion results are placed in consecutive result registers (wrap around at end).
1–0
FRZ[1:0]
Background Debug Freeze Enable — When debugging an application, it is useful in many cases to have the
ATD pause when a breakpoint (Freeze Mode) is encountered. These 2 bits determine how the ATD will respond
to a breakpoint as shown in Table 10-11. Leakage onto the storage node and comparator reference capacitors
may compromise the accuracy of an immediately frozen conversion depending on the length of the freeze period.
S12XS Family Reference Manual, Rev. 1.10
280
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-9. Examples of ideal decimal ATD Results
Input Signal
VRL = 0 Volts
VRH = 5.12 Volts
8-Bit
Codes
(resolution=20mV)
10-Bit
Codes
(resolution=5mV)
12-Bit
Codes
(transfer curve has
1.25mV offset)
(resolution=1.25mV)
5.120 Volts
...
0.022
0.020
0.018
0.016
0.014
0.012
0.010
0.008
0.006
0.004
0.003
0.002
0.000
255
...
1
1
1
1
1
1
1
0
0
0
0
0
0
1023
...
4
4
4
3
3
2
2
2
1
1
0
0
0
4095
...
17
16
14
12
11
9
8
6
4
3
2
1
0
Table 10-10. Conversion Sequence Length Coding
S8C
S4C
S2C
S1C
Number of Conversions
per Sequence
0
0
0
0
16
0
0
0
1
1
0
0
1
0
2
0
0
1
1
3
0
1
0
0
4
0
1
0
1
5
0
1
1
0
6
0
1
1
1
7
1
0
0
0
8
1
0
0
1
9
1
0
1
0
10
1
0
1
1
11
1
1
0
0
12
1
1
0
1
13
1
1
1
0
14
1
1
1
1
15
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
281
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-11. ATD Behavior in Freeze Mode (Breakpoint)
10.3.2.5
FRZ1
FRZ0
Behavior in Freeze Mode
0
0
Continue conversion
0
1
Reserved
1
0
Finish current conversion, then freeze
1
1
Freeze Immediately
ATD Control Register 4 (ATDCTL4)
Writes to this register will abort current conversion sequence.
Module Base + 0x0004
7
6
5
SMP2
SMP1
SMP0
0
0
0
4
3
2
1
0
0
1
R
PRS[4:0]
W
Reset
0
0
1
Figure 10-7. ATD Control Register 4 (ATDCTL4)
Read: Anytime
Write: Anytime
Table 10-12. ATDCTL4 Field Descriptions
Field
Description
7–5
SMP[2:0]
Sample Time Select — These three bits select the length of the sample time in units of ATD conversion clock
cycles. Note that the ATD conversion clock period is itself a function of the prescaler value (bits PRS4-0).
Table 10-13 lists the available sample time lengths.
4–0
PRS[4:0]
ATD Clock Prescaler — These 5 bits are the binary prescaler value PRS. The ATD conversion clock frequency
is calculated as follows:
f BUS
f ATDCLK = ------------------------------------2 × ( PRS + 1 )
Refer to Device Specification for allowed frequency range of fATDCLK.
Table 10-13. Sample Time Select
SMP2
SMP1
SMP0
Sample Time
in Number of
ATD Clock Cycles
0
0
0
4
0
0
1
6
0
1
0
8
0
1
1
10
1
0
0
12
1
0
1
16
1
1
0
20
S12XS Family Reference Manual, Rev. 1.10
282
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-13. Sample Time Select
10.3.2.6
SMP2
SMP1
SMP0
Sample Time
in Number of
ATD Clock Cycles
1
1
1
24
ATD Control Register 5 (ATDCTL5)
Writes to this register will abort current conversion sequence and start a new conversion sequence. If
external trigger is enabled (ETRIGE=1) an initial write to ATDCTL5 is required to allow starting of a
conversion sequence which will then occur on each trigger event. Start of conversion means the beginning
of the sampling phase.
Module Base + 0x0005
7
R
6
5
4
3
2
1
0
SC
SCAN
MULT
CD
CC
CB
CA
0
0
0
0
0
0
0
0
W
Reset
0
Figure 10-8. ATD Control Register 5 (ATDCTL5)
Read: Anytime
Write: Anytime
Table 10-14. ATDCTL5 Field Descriptions
Field
Description
6
SC
Special Channel Conversion Bit — If this bit is set, then special channel conversion can be selected using CD,
CC, CB and CA of ATDCTL5. Table 10-15 lists the coding.
0 Special channel conversions disabled
1 Special channel conversions enabled
5
SCAN
Continuous Conversion Sequence Mode — This bit selects whether conversion sequences are performed
continuously or only once. If external trigger is enabled (ETRIGE=1) setting this bit has no effect, that means
external trigger always starts a single conversion sequence.
0 Single conversion sequence
1 Continuous conversion sequences (scan mode)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
283
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-14. ATDCTL5 Field Descriptions (continued)
Field
Description
4
MULT
Multi-Channel Sample Mode — When MULT is 0, the ATD sequence controller samples only from the specified
analog input channel for an entire conversion sequence. The analog channel is selected by channel selection
code (control bits CD/CC/CB/CA located in ATDCTL5). When MULT is 1, the ATD sequence controller samples
across channels. The number of channels sampled is determined by the sequence length value (S8C, S4C, S2C,
S1C). The first analog channel examined is determined by channel selection code (CD, CC, CB, CA control bits);
subsequent channels sampled in the sequence are determined by incrementing the channel selection code or
wrapping around to AN0 (channel 0).
0 Sample only one channel
1 Sample across several channels
3–0
CD, CC,
CB, CA
Analog Input Channel Select Code — These bits select the analog input channel(s) whose signals are
sampled and converted to digital codes. Table 10-15 lists the coding used to select the various analog input
channels.
In the case of single channel conversions (MULT=0), this selection code specifies the channel to be examined.
In the case of multiple channel conversions (MULT=1), this selection code specifies the first channel to be
examined in the conversion sequence. Subsequent channels are determined by incrementing the channel
selection code or wrapping around to AN0 (after converting the channel defined by the Wrap Around Channel
Select Bits WRAP3-0 in ATDCTL0). In case of starting with a channel number higher than the one defined by
WRAP3-0 the first wrap around will be AN15 to AN0.
Table 10-15. Analog Input Channel Select Coding
SC
CD
CC
CB
CA
Analog Input
Channel
0
0
0
0
0
AN0
0
0
0
1
AN1
0
0
1
0
AN2
0
0
1
1
AN3
0
1
0
0
AN4
0
1
0
1
AN5
0
1
1
0
AN6
0
1
1
1
AN7
1
0
0
0
AN8
1
0
0
1
AN9
1
0
1
0
AN10
1
0
1
1
AN11
1
1
0
0
AN12
1
1
0
1
AN13
1
1
1
0
AN14
1
1
1
1
AN15
S12XS Family Reference Manual, Rev. 1.10
284
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-15. Analog Input Channel Select Coding
SC
CD
CC
CB
CA
Analog Input
Channel
1
0
0
0
0
Reserved
0
0
0
1
Reserved
0
0
1
X
Reserved
0
1
0
0
VRH
0
1
0
1
VRL
0
1
1
0
(VRH+VRL) / 2
0
1
1
1
Reserved
1
X
X
X
Reserved
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
285
Analog-to-Digital Converter (ADC12B16CV1)
10.3.2.7
ATD Status Register 0 (ATDSTAT0)
This register contains the Sequence Complete Flag, overrun flags for external trigger and FIFO mode, and
the conversion counter.
Module Base + 0x0006
7
R
6
5
4
ETORF
FIFOR
0
0
0
SCF
3
2
1
0
CC3
CC2
CC1
CC0
0
0
0
0
W
Reset
0
0
= Unimplemented or Reserved
Figure 10-9. ATD Status Register 0 (ATDSTAT0)
Read: Anytime
Write: Anytime (No effect on (CC3, CC2, CC1, CC0))
Table 10-16. ATDSTAT0 Field Descriptions
Field
Description
7
SCF
Sequence Complete Flag — This flag is set upon completion of a conversion sequence. If conversion
sequences are continuously performed (SCAN=1), the flag is set after each one is completed. This flag is cleared
when one of the following occurs:
A) Write “1” to SCF
B) Write to ATDCTL5 (a new conversion sequence is started)
C) If AFFC=1 and read of a result register
0 Conversion sequence not completed
1 Conversion sequence has completed
5
ETORF
External Trigger Overrun Flag — While in edge trigger mode (ETRIGLE=0), if additional active edges are
detected while a conversion sequence is in process the overrun flag is set. This flag is cleared when one of the
following occurs:
A) Write “1” to ETORF
B) Write to ATDCTL0,1,2,3,4, ATDCMPE or ATDCMPHT (a conversion sequence is aborted)
C) Write to ATDCTL5 (a new conversion sequence is started)
0 No External trigger over run error has occurred
1 External trigger over run error has occurred
4
FIFOR
Result Register Over Run Flag — This bit indicates that a result register has been written to before its
associated conversion complete flag (CCF) has been cleared. This flag is most useful when using the FIFO mode
because the flag potentially indicates that result registers are out of sync with the input channels. However, it is
also practical for non-FIFO modes, and indicates that a result register has been over written before it has been
read (i.e. the old data has been lost). This flag is cleared when one of the following occurs:
A) Write “1” to FIFOR
B) Write to ATDCTL0,1,2,3,4, ATDCMPE or ATDCMPHT (a conversion sequence is aborted)
C) Write to ATDCTL5 (a new conversion sequence is started)
0 No over run has occurred
1 Overrun condition exists (result register has been written while associated CCFx flag was still set)
S12XS Family Reference Manual, Rev. 1.10
286
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-16. ATDSTAT0 Field Descriptions (continued)
Field
Description
3–0
CC[3:0]
Conversion Counter — These 4 read-only bits are the binary value of the conversion counter. The conversion
counter points to the result register that will receive the result of the current conversion. E.g. CC3=0, CC2=1,
CC1=1, CC0=0 indicates that the result of the current conversion will be in ATD Result Register 6. If in non-FIFO
mode (FIFO=0) the conversion counter is initialized to zero at the begin and end of the conversion sequence. If
in FIFO mode (FIFO=1) the register counter is not initialized. The conversion counters wraps around when its
maximum value is reached.
Aborting a conversion or starting a new conversion clears the conversion counter even if FIFO=1.
10.3.2.8
ATD Compare Enable Register (ATDCMPE)
Writes to this register will abort current conversion sequence.
Read: Anytime
Write: Anytime
Module Base + 0x0008
15
14
13
12
11
10
9
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
CMPE[15:0]
W
Reset
8
0
0
0
0
0
0
0
0
0
Figure 10-10. ATD Compare Enable Register (ATDCMPE)
Table 10-17. ATDCMPE Field Descriptions
Field
Description
15–0
Compare Enable for Conversion Number n (n= 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) of a Sequence
CMPE[15:0] — These bits enable automatic compare of conversion results individually for conversions of a sequence. The
sense of each comparison is determined by the CMPHT[n] bit in the ATDCMPHT register.
For each conversion number with CMPE[n]=1 do the following:
1) Write compare value to ATDDRn result register
2) Write compare operator with CMPHT[n] in ATDCPMHT register
CCF[n] in ATDSTAT2 register will flag individual success of any comparison.
0 No automatic compare
1 Automatic compare of results for conversion n of a sequence is enabled.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
287
Analog-to-Digital Converter (ADC12B16CV1)
10.3.2.9
ATD Status Register 2 (ATDSTAT2)
This read-only register contains the Conversion Complete Flags CCF[15:0].
Module Base + 0x000A
15
14
13
12
11
10
9
R
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
CCF[15:0]
W
Reset
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 10-11. ATD Status Register 2 (ATDSTAT2)
Read: Anytime
Write: Anytime, no effect
Table 10-18. ATDSTAT2 Field Descriptions
Field
Description
15–0
CCF[15:0]
Conversion Complete Flag n (n= 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) — A conversion complete
flag is set at the end of each conversion in a sequence. The flags are associated with the conversion position in
a sequence (and also the result register number). Therefore in non-fifo mode, CCF[8] is set when the ninth
conversion in a sequence is complete and the result is available in result register ATDDR8; CCF[9] is set when
the tenth conversion in a sequence is complete and the result is available in ATDDR9, and so forth.
If automatic compare of conversion results is enabled (CMPE[n]=1 in ATDCMPE), the conversion complete flag
is only set if comparison with ATDDRn is true and if ACMPIE=1 a compare interrupt will be requested. In this
case, as the ATDDRn result register is used to hold the compare value, the result will not be stored there at the
end of the conversion but is lost.
A flag CCF[n] is cleared when one of the following occurs:
A) Write to ATDCTL5 (a new conversion sequence is started)
B) If AFFC=0, write “1” to CCF[n]
C) If AFFC=1 and CMPE[n]=0, read of result register ATDDRn
D) If AFFC=1 and CMPE[n]=1, write to result register ATDDRn
In case of a concurrent set and clear on CCF[n]: The clearing by method A) will overwrite the set. The clearing
by methods B) or C) or D) will be overwritten by the set.
0 Conversion number n not completed or successfully compared
1 If (CMPE[n]=0): Conversion number n has completed. Result is ready in ATDDRn.
If (CMPE[n]=1): Compare for conversion result number n with compare value in ATDDRn, using compare
operator CMPGT[n] is true. (No result available in ATDDRn)
S12XS Family Reference Manual, Rev. 1.10
288
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
10.3.2.10 ATD Input Enable Register (ATDDIEN)
Module Base + 0x000C
15
14
13
12
11
10
9
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
IEN[15:0]
W
Reset
8
0
0
0
0
0
0
0
0
0
Figure 10-12. ATD Input Enable Register (ATDDIEN)
Read: Anytime
Write: Anytime
Table 10-19. ATDDIEN Field Descriptions
Field
Description
15–0
IEN[15:0]
ATD Digital Input Enable on channel x (x= 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) — This bit controls
the digital input buffer from the analog input pin (ANx) to the digital data register.
0 Disable digital input buffer to ANx pin
1 Enable digital input buffer on ANx pin.
Note: Setting this bit will enable the corresponding digital input buffer continuously. If this bit is set while
simultaneously using it as an analog port, there is potentially increased power consumption because the
digital input buffer maybe in the linear region.
10.3.2.11 ATD Compare Higher Than Register (ATDCMPHT)
Writes to this register will abort current conversion sequence.
Read: Anytime
Write: Anytime
Module Base + 0x000E
15
14
13
12
11
10
9
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
CMPHT[15:0]
W
Reset
8
0
0
0
0
0
0
0
0
0
Figure 10-13. ATD Compare Higher Than Register (ATDCMPHT)
Table 10-20. ATDCMPHT Field Descriptions
Field
Description
15–0
Compare Operation Higher Than Enable for conversion number n (n= 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5,
CMPHT[15:0] 4, 3, 2, 1, 0) of a Sequence — This bit selects the operator for comparison of conversion results.
0 If result of conversion n is lower or same than compare value in ATDDRn, this is flagged in ATDSTAT2
1 If result of conversion n is higher than compare value in ATDDRn, this is flagged in ATDSTAT2
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
289
Analog-to-Digital Converter (ADC12B16CV1)
10.3.2.12 ATD Conversion Result Registers (ATDDRn)
The A/D conversion results are stored in 16 result registers. Results are always in unsigned data
representation. Left and right justification is selected using the DJM control bit in ATDCTL3.
If automatic compare of conversions results is enabled (CMPE[n]=1 in ATDCMPE), these registers must
be written with the compare values in left or right justified format depending on the actual value of the
DJM bit. In this case, as the ATDDRn register is used to hold the compare value, the result will not be
stored there at the end of the conversion but is lost.
Read: Anytime
Write: Anytime
NOTE
For conversions not using automatic compare, results are stored in the result
registers after each conversion. In this case avoid writing to ATDDRn except
for initial values, because an A/D result might be overwritten.
10.3.2.12.1 Left Justified Result Data (DJM=0)
Module Base +
0x0010 = ATDDR0, 0x0012 = ATDDR1, 0x0014 = ATDDR2, 0x0016 = ATDDR3
0x0018 = ATDDR4, 0x001A = ATDDR5, 0x001C = ATDDR6, 0x001E = ATDDR7
0x0020 = ATDDR8, 0x0022 = ATDDR9, 0x0024 = ATDDR10, 0x0026 = ATDDR11
0x0028 = ATDDR12, 0x002A = ATDDR13, 0x002C = ATDDR14, 0x002E = ATDDR15
15
R
W
Reset
14
13
Bit 11 Bit 10 Bit 9
0
0
0
12
11
10
9
8
7
6
5
4
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
0
0
0
0
0
0
0
3
2
1
0
0
0
0
0
0
0
0
0
Figure 10-14. Left justified ATD conversion result register (ATDDRn)
10.3.2.12.2 Right Justified Result Data (DJM=1)
Module Base +
0x0010 = ATDDR0, 0x0012 = ATDDR1, 0x0014 = ATDDR2, 0x0016 = ATDDR3
0x0018 = ATDDR4, 0x001A = ATDDR5, 0x001C = ATDDR6, 0x001E = ATDDR7
0x0020 = ATDDR8, 0x0022 = ATDDR9, 0x0024 = ATDDR10, 0x0026 = ATDDR11
0x0028 = ATDDR12, 0x002A = ATDDR13, 0x002C = ATDDR14, 0x002E = ATDDR15
R
15
14
13
12
0
0
0
0
0
0
0
0
W
Reset
11
10
9
Bit 11 Bit 10 Bit 9
0
0
0
8
7
6
5
4
3
2
1
0
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bi1 1
Bit 0
0
0
0
0
0
0
0
0
0
Figure 10-15. Right justified ATD conversion result register (ATDDRn)
Table 10-15 shows how depending on the A/D resolution the conversion result is transferred to the ATD
result registers. Compare is always done using all 12 bits of both the conversion result and the compare
value in ATDDRn.
S12XS Family Reference Manual, Rev. 1.10
290
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
Table 10-21. Conversion result mapping to ATDDRn
A/D
resolution
DJM
conversion result mapping to
ATDDRn
8-bit data
0
Bit[11:4] = result, Bit[3:0]=0000
8-bit data
1
Bit[7:0] = result, Bit[11:8]=0000
10-bit data
0
Bit[11:2] = result, Bit[1:0]=00
10-bit data
1
Bit[9:0] = result, Bit[11:10]=00
12-bit data
X
Bit[11:0] = result
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
291
Analog-to-Digital Converter (ADC12B16CV1)
10.4
Functional Description
The ADC12B16C is structured into an analog sub-block and a digital sub-block.
10.4.1
Analog Sub-Block
The analog sub-block contains all analog electronics required to perform a single conversion. Separate
power supplies VDDA and VSSA allow to isolate noise of other MCU circuitry from the analog sub-block.
10.4.1.1
Sample and Hold Machine
The Sample and Hold (S/H) Machine accepts analog signals from the external world and stores them as
capacitor charge on a storage node.
During the sample process the analog input connects directly to the storage node.
The input analog signals are unipolar and must fall within the potential range of VSSA to VDDA.
During the hold process the analog input is disconnected from the storage node.
10.4.1.2
Analog Input Multiplexer
The analog input multiplexer connects one of the 16 external analog input channels to the sample and hold
machine.
10.4.1.3
Analog-to-Digital (A/D) Machine
The A/D Machine performs analog to digital conversions. The resolution is program selectable at either 8
or 10 or 12 bits. The A/D machine uses a successive approximation architecture. It functions by comparing
the stored analog sample potential with a series of digitally generated analog potentials. By following a
binary search algorithm, the A/D machine locates the approximating potential that is nearest to the
sampled potential.
When not converting the A/D machine is automatically powered down.
Only analog input signals within the potential range of VRL to VRH (A/D reference potentials) will result
in a non-railed digital output code.
10.4.2
Digital Sub-Block
This subsection explains some of the digital features in more detail. See Section 10.3.2, “Register
Descriptions” for all details.
10.4.2.1
External Trigger Input
The external trigger feature allows the user to synchronize ATD conversions to the external environment
events rather than relying on software to signal the ATD module when ATD conversions are to take place.
The external trigger signal (out of reset ATD channel 15, configurable in ATDCTL1) is programmable to
S12XS Family Reference Manual, Rev. 1.10
292
Freescale Semiconductor
Analog-to-Digital Converter (ADC12B16CV1)
be edge or level sensitive with polarity control. Table 10-22 gives a brief description of the different
combinations of control bits and their effect on the external trigger function.
Table 10-22. External Trigger Control Bits
ETRIGLE
ETRIGP
ETRIGE
SCAN
Description
X
X
0
0
Ignores external trigger. Performs one
conversion sequence and stops.
X
X
0
1
Ignores external trigger. Performs
continuous conversion sequences.
0
0
1
X
Falling edge triggered. Performs one
conversion sequence per trigger.
0
1
1
X
Rising edge triggered. Performs one
conversion sequence per trigger.
1
0
1
X
Trigger active low. Performs continuous
conversions while trigger is active.
1
1
1
X
Trigger active high. Performs continuous
conversions while trigger is active.
During a conversion, if additional active edges are detected the overrun error flag ETORF is set.
In either level or edge triggered modes, the first conversion begins when the trigger is received.
Once ETRIGE is enabled, conversions cannot be started by a write to ATDCTL5, but rather must be
triggered externally.
If the level mode is active and the external trigger both de-asserts and re-asserts itself during a conversion
sequence, this does not constitute an overrun. Therefore, the flag is not set. If the trigger is left asserted in
level mode while a sequence is completing, another sequence will be triggered immediately.
10.4.2.2
General-Purpose Digital Port Operation
The input channel pins can be multiplexed between analog and digital data. As analog inputs, they are
multiplexed and sampled as analog channels to the A/D converter. The analog/digital multiplex operation
is performed in the input pads. The input pad is always connected to the analog input channels of the
ADC12B16C. The input pad signal is buffered to the digital port registers. This buffer can be turned on or
off with the ATDDIEN register. This is important so that the buffer does not draw excess current when
analog potentials are presented at its input.
10.5
Resets
At reset the ADC12B16C is in a power down state. The reset state of each individual bit is listed within
the Register Description section (see Section 10.3.2, “Register Descriptions”) which details the registers
and their bit-field.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
293
Analog-to-Digital Converter (ADC12B16CV1)
10.6
Interrupts
The interrupts requested by the ADC12B16C are listed in Table 10-23. Refer to MCU specification for
related vector address and priority.
Table 10-23. ATD Interrupt Vectors
Interrupt Source
CCR
Mask
Local Enable
Sequence Complete Interrupt
I bit
ASCIE in ATDCTL2
Compare Interrupt
I bit
ACMPIE in ATDCTL2
See Section 10.3.2, “Register Descriptions” for further details.
S12XS Family Reference Manual, Rev. 1.10
294
Freescale Semiconductor
Chapter 11
Freescale’s Scalable Controller Area Network
(S12MSCANV3)
Table 11-1. Revision History
Revision
Number
Revision Date
V03.09
04 May 2007
V03.10
19 Aug 2008
V03.11
31 Mar 2009
11.1
Sections
Affected
11.3.2.11/11313
Description of Changes
- Corrected mnemonics of code example in CANTBSEL register description
11.4.7.4/11-347 - Corrected wake-up description
11.4.4.5/11-341 - Relocated initialization section
11.2/11-298
- Added note to external pin descriptions for use with integrated physical layer
- Minor corrections
- Orthographic corrections
Introduction
Freescale’s scalable controller area network (S12MSCANV3) definition is based on the MSCAN12
definition, which is the specific implementation of the MSCAN concept targeted for the M68HC12
microcontroller family.
The module is a communication controller implementing the CAN 2.0A/B protocol as defined in the
Bosch specification dated September 1991. For users to fully understand the MSCAN specification, it is
recommended that the Bosch specification be read first to familiarize the reader with the terms and
concepts contained within this document.
Though not exclusively intended for automotive applications, CAN protocol is designed to meet the
specific requirements of a vehicle serial data bus: real-time processing, reliable operation in the EMI
environment of a vehicle, cost-effectiveness, and required bandwidth.
MSCAN uses an advanced buffer arrangement resulting in predictable real-time behavior and simplified
application software.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
295
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.1.1
Glossary
Table 11-2. Terminology
ACK
Acknowledge of CAN message
CAN
Controller Area Network
CRC
Cyclic Redundancy Code
EOF
End of Frame
FIFO
First-In-First-Out Memory
IFS
Inter-Frame Sequence
SOF
Start of Frame
CPU bus
CPU related read/write data bus
CAN bus
CAN protocol related serial bus
oscillator clock
11.1.2
Direct clock from external oscillator
bus clock
CPU bus related clock
CAN clock
CAN protocol related clock
Block Diagram
MSCAN
Oscillator Clock
Bus Clock
CANCLK
MUX
Presc.
Tq Clk
Receive/
Transmit
Engine
RXCAN
TXCAN
Transmit Interrupt Req.
Receive Interrupt Req.
Errors Interrupt Req.
Message
Filtering
and
Buffering
Control
and
Status
Wake-Up Interrupt Req.
Configuration
Registers
Wake-Up
Low Pass Filter
Figure 11-1. MSCAN Block Diagram
S12XS Family Reference Manual, Rev. 1.10
296
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.1.3
Features
The basic features of the MSCAN are as follows:
• Implementation of the CAN protocol — Version 2.0A/B
— Standard and extended data frames
— Zero to eight bytes data length
— Programmable bit rate up to 1 Mbps1
— Support for remote frames
• Five receive buffers with FIFO storage scheme
• Three transmit buffers with internal prioritization using a “local priority” concept
• Flexible maskable identifier filter supports two full-size (32-bit) extended identifier filters, or four
16-bit filters, or eight 8-bit filters
• Programmable wake-up functionality with integrated low-pass filter
• Programmable loopback mode supports self-test operation
• Programmable listen-only mode for monitoring of CAN bus
• Programmable bus-off recovery functionality
• Separate signalling and interrupt capabilities for all CAN receiver and transmitter error states
(warning, error passive, bus-off)
• Programmable MSCAN clock source either bus clock or oscillator clock
• Internal timer for time-stamping of received and transmitted messages
• Three low-power modes: sleep, power down, and MSCAN enable
• Global initialization of configuration registers
11.1.4
Modes of Operation
For a description of the specific MSCAN modes and the module operation related to the system operating
modes refer to Section 11.4.4, “Modes of Operation”.
1. Depending on the actual bit timing and the clock jitter of the PLL.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
297
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.2
External Signal Description
The MSCAN uses two external pins.
NOTE
On MCUs with an integrated CAN physical interface (transceiver) the
MSCAN interface is connected internally to the transceiver interface. In
these cases the external availability of signals TXCAN and RXCAN is
optional.
11.2.1
RXCAN — CAN Receiver Input Pin
RXCAN is the MSCAN receiver input pin.
11.2.2
TXCAN — CAN Transmitter Output Pin
TXCAN is the MSCAN transmitter output pin. The TXCAN output pin represents the logic level on the
CAN bus:
0 = Dominant state
1 = Recessive state
11.2.3
CAN System
A typical CAN system with MSCAN is shown in Figure 11-2. Each CAN station is connected physically
to the CAN bus lines through a transceiver device. The transceiver is capable of driving the large current
needed for the CAN bus and has current protection against defective CAN or defective stations.
CAN node 2
CAN node 1
CAN node n
MCU
CAN Controller
(MSCAN)
TXCAN
RXCAN
Transceiver
CANH
CANL
CAN Bus
Figure 11-2. CAN System
S12XS Family Reference Manual, Rev. 1.10
298
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the MSCAN.
11.3.1
Module Memory Map
Figure 11-3 gives an overview on all registers and their individual bits in the MSCAN memory map. The
register address results from the addition of base address and address offset. The base address is
determined at the MCU level and can be found in the MCU memory map description. The address offset
is defined at the module level.
The MSCAN occupies 64 bytes in the memory space. The base address of the MSCAN module is
determined at the MCU level when the MCU is defined. The register decode map is fixed and begins at the
first address of the module address offset.
The detailed register descriptions follow in the order they appear in the register map.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
299
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Register
Name
Bit 7
0x0000
CANCTL0
R
0x0001
CANCTL1
R
W
W
0x0002
CANBTR0
R
0x0003
CANBTR1
R
0x0004
CANRFLG
R
0x0005
CANRIER
R
0x0006
CANTFLG
R
0x0007
CANTIER
0x0008
CANTARQ
W
W
W
W
R
R
W
0x000E
CANRXERR
SYNCH
3
2
1
Bit 0
TIME
WUPE
SLPRQ
INITRQ
SLPAK
INITAK
CANE
CLKSRC
LOOPB
LISTEN
BORM
WUPM
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
SAMP
TSEG22
TSEG21
TSEG20
TSEG13
TSEG12
TSEG11
TSEG10
WUPIF
CSCIF
RSTAT1
RSTAT0
TSTAT1
TSTAT0
OVRIF
RXF
WUPIE
CSCIE
RSTATE1
RSTATE0
TSTATE1
TSTATE0
OVRIE
RXFIE
0
0
0
0
0
TXE2
TXE1
TXE0
0
0
0
0
0
TXEIE2
TXEIE1
TXEIE0
0
0
0
0
0
ABTRQ2
ABTRQ1
ABTRQ0
0
0
0
0
0
ABTAK2
ABTAK1
ABTAK0
0
0
0
0
0
TX2
TX1
TX0
0
0
IDAM1
IDAM0
0
IDHIT2
IDHIT1
IDHIT0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RXERR7
RXERR6
RXERR5
RXERR4
RXERR3
RXERR2
RXERR1
W
0x000A
CANTBSEL
0x000D
CANMISC
CSWAI
4
W
W
0x000C
Reserved
RXACT
5
W
0x0009
CANTAAK
0x000B
CANIDAC
RXFRM
6
R
R
R
W
R
W
R
W
R
BOHOLD
RXERR0
W
= Unimplemented or Reserved
Figure 11-3. MSCAN Register Summary
S12XS Family Reference Manual, Rev. 1.10
300
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Register
Name
0x000F
CANTXERR
R
0x0010–0x0013
CANIDAR0–3
R
0x0014–0x0017
CANIDMRx
R
0x0018–0x001B
CANIDAR4–7
R
0x001C–0x001F
CANIDMR4–7
R
0x0020–0x002F
CANRXFG
R
0x0030–0x003F
CANTXFG
R
Bit 7
6
5
4
3
2
1
Bit 0
TXERR7
TXERR6
TXERR5
TXERR4
TXERR3
TXERR2
TXERR1
TXERR0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
W
W
W
W
W
See Section 11.3.3, “Programmer’s Model of Message Storage”
W
See Section 11.3.3, “Programmer’s Model of Message Storage”
W
= Unimplemented or Reserved
Figure 11-3. MSCAN Register Summary (continued)
11.3.2
Register Descriptions
This section describes in detail all the registers and register bits in the MSCAN module. Each description
includes a standard register diagram with an associated figure number. Details of register bit and field
function follow the register diagrams, in bit order. All bits of all registers in this module are completely
synchronous to internal clocks during a register read.
11.3.2.1
MSCAN Control Register 0 (CANCTL0)
The CANCTL0 register provides various control bits of the MSCAN module as described below.
Access: User read/write(1)
Module Base + 0x0000
7
R
6
5
RXACT
RXFRM
4
3
2
1
0
TIME
WUPE
SLPRQ
INITRQ
0
0
0
1
SYNCH
CSWAI
W
Reset:
0
0
0
0
= Unimplemented
Figure 11-4. MSCAN Control Register 0 (CANCTL0)
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
301
Freescale’s Scalable Controller Area Network (S12MSCANV3)
1. Read: Anytime
Write: Anytime when out of initialization mode; exceptions are read-only RXACT and SYNCH, RXFRM (which is set by the
module only), and INITRQ (which is also writable in initialization mode)
NOTE
The CANCTL0 register, except WUPE, INITRQ, and SLPRQ, is held in the
reset state when the initialization mode is active (INITRQ = 1 and
INITAK = 1). This register is writable again as soon as the initialization
mode is exited (INITRQ = 0 and INITAK = 0).
Table 11-3. CANCTL0 Register Field Descriptions
Field
Description
7
RXFRM(1)
Received Frame Flag — This bit is read and clear only. It is set when a receiver has received a valid message
correctly, independently of the filter configuration. After it is set, it remains set until cleared by software or reset.
Clearing is done by writing a 1. Writing a 0 is ignored. This bit is not valid in loopback mode.
0 No valid message was received since last clearing this flag
1 A valid message was received since last clearing of this flag
6
RXACT
Receiver Active Status — This read-only flag indicates the MSCAN is receiving a message. The flag is
controlled by the receiver front end. This bit is not valid in loopback mode.
0 MSCAN is transmitting or idle2
1 MSCAN is receiving a message (including when arbitration is lost)(2)
5
CSWAI(3)
CAN Stops in Wait Mode — Enabling this bit allows for lower power consumption in wait mode by disabling all
the clocks at the CPU bus interface to the MSCAN module.
0 The module is not affected during wait mode
1 The module ceases to be clocked during wait mode
4
SYNCH
Synchronized Status — This read-only flag indicates whether the MSCAN is synchronized to the CAN bus and
able to participate in the communication process. It is set and cleared by the MSCAN.
0 MSCAN is not synchronized to the CAN bus
1 MSCAN is synchronized to the CAN bus
3
TIME
Timer Enable — This bit activates an internal 16-bit wide free running timer which is clocked by the bit clock rate.
If the timer is enabled, a 16-bit time stamp will be assigned to each transmitted/received message within the
active TX/RX buffer. Right after the EOF of a valid message on the CAN bus, the time stamp is written to the
highest bytes (0x000E, 0x000F) in the appropriate buffer (see Section 11.3.3, “Programmer’s Model of Message
Storage”). The internal timer is reset (all bits set to 0) when disabled. This bit is held low in initialization mode.
0 Disable internal MSCAN timer
1 Enable internal MSCAN timer
2
WUPE(4)
Wake-Up Enable — This configuration bit allows the MSCAN to restart from sleep mode or from power down
mode (entered from sleep) when traffic on CAN is detected (see Section 11.4.5.5, “MSCAN Sleep Mode”). This
bit must be configured before sleep mode entry for the selected function to take effect.
0 Wake-up disabled — The MSCAN ignores traffic on CAN
1 Wake-up enabled — The MSCAN is able to restart
S12XS Family Reference Manual, Rev. 1.10
302
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-3. CANCTL0 Register Field Descriptions (continued)
Field
Description
1
SLPRQ(5)
Sleep Mode Request — This bit requests the MSCAN to enter sleep mode, which is an internal power saving
mode (see Section 11.4.5.5, “MSCAN Sleep Mode”). The sleep mode request is serviced when the CAN bus is
idle, i.e., the module is not receiving a message and all transmit buffers are empty. The module indicates entry
to sleep mode by setting SLPAK = 1 (see Section 11.3.2.2, “MSCAN Control Register 1 (CANCTL1)”). SLPRQ
cannot be set while the WUPIF flag is set (see Section 11.3.2.5, “MSCAN Receiver Flag Register (CANRFLG)”).
Sleep mode will be active until SLPRQ is cleared by the CPU or, depending on the setting of WUPE, the MSCAN
detects activity on the CAN bus and clears SLPRQ itself.
0 Running — The MSCAN functions normally
1 Sleep mode request — The MSCAN enters sleep mode when CAN bus idle
0
Initialization Mode Request — When this bit is set by the CPU, the MSCAN skips to initialization mode (see
INITRQ(6),(7) Section 11.4.4.5, “MSCAN Initialization Mode”). Any ongoing transmission or reception is aborted and
synchronization to the CAN bus is lost. The module indicates entry to initialization mode by setting INITAK = 1
(Section 11.3.2.2, “MSCAN Control Register 1 (CANCTL1)”).
The following registers enter their hard reset state and restore their default values: CANCTL0(8), CANRFLG(9),
CANRIER(10), CANTFLG, CANTIER, CANTARQ, CANTAAK, and CANTBSEL.
The registers CANCTL1, CANBTR0, CANBTR1, CANIDAC, CANIDAR0-7, and CANIDMR0-7 can only be
written by the CPU when the MSCAN is in initialization mode (INITRQ = 1 and INITAK = 1). The values of the
error counters are not affected by initialization mode.
When this bit is cleared by the CPU, the MSCAN restarts and then tries to synchronize to the CAN bus. If the
MSCAN is not in bus-off state, it synchronizes after 11 consecutive recessive bits on the CAN bus; if the MSCAN
is in bus-off state, it continues to wait for 128 occurrences of 11 consecutive recessive bits.
Writing to other bits in CANCTL0, CANRFLG, CANRIER, CANTFLG, or CANTIER must be done only after
initialization mode is exited, which is INITRQ = 0 and INITAK = 0.
0 Normal operation
1 MSCAN in initialization mode
1. The MSCAN must be in normal mode for this bit to become set.
2. See the Bosch CAN 2.0A/B specification for a detailed definition of transmitter and receiver states.
3. In order to protect from accidentally violating the CAN protocol, TXCAN is immediately forced to a recessive state when the
CPU enters wait (CSWAI = 1) or stop mode (see Section 11.4.5.2, “Operation in Wait Mode” and Section 11.4.5.3, “Operation
in Stop Mode”).
4. The CPU has to make sure that the WUPE register and the WUPIE wake-up interrupt enable register (see Section 11.3.2.6,
“MSCAN Receiver Interrupt Enable Register (CANRIER)) is enabled, if the recovery mechanism from stop or wait is required.
5. The CPU cannot clear SLPRQ before the MSCAN has entered sleep mode (SLPRQ = 1 and SLPAK = 1).
6. The CPU cannot clear INITRQ before the MSCAN has entered initialization mode (INITRQ = 1 and INITAK = 1).
7. In order to protect from accidentally violating the CAN protocol, TXCAN is immediately forced to a recessive state when the
initialization mode is requested by the CPU. Thus, the recommended procedure is to bring the MSCAN into sleep mode
(SLPRQ = 1 and SLPAK = 1) before requesting initialization mode.
8. Not including WUPE, INITRQ, and SLPRQ.
9. TSTAT1 and TSTAT0 are not affected by initialization mode.
10. RSTAT1 and RSTAT0 are not affected by initialization mode.
11.3.2.2
MSCAN Control Register 1 (CANCTL1)
The CANCTL1 register provides various control bits and handshake status information of the MSCAN
module as described below.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
303
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Access: User read/write(1)
Module Base + 0x0001
7
6
5
4
3
2
CANE
CLKSRC
LOOPB
LISTEN
BORM
WUPM
0
0
0
1
0
0
R
1
0
SLPAK
INITAK
0
1
W
Reset:
= Unimplemented
Figure 11-5. MSCAN Control Register 1 (CANCTL1)
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1); CANE is write once
Table 11-4. CANCTL1 Register Field Descriptions
Field
7
CANE
Description
MSCAN Enable
0 MSCAN module is disabled
1 MSCAN module is enabled
6
CLKSRC
MSCAN Clock Source — This bit defines the clock source for the MSCAN module (only for systems with a clock
generation module; Section 11.4.3.2, “Clock System,” and Section Figure 11-43., “MSCAN Clocking Scheme,”).
0 MSCAN clock source is the oscillator clock
1 MSCAN clock source is the bus clock
5
LOOPB
Loopback Self Test Mode — When this bit is set, the MSCAN performs an internal loopback which can be used
for self test operation. The bit stream output of the transmitter is fed back to the receiver internally. The RXCAN
input is ignored and the TXCAN output goes to the recessive state (logic 1). The MSCAN behaves as it does
normally when transmitting and treats its own transmitted message as a message received from a remote node.
In this state, the MSCAN ignores the bit sent during the ACK slot in the CAN frame acknowledge field to ensure
proper reception of its own message. Both transmit and receive interrupts are generated.
0 Loopback self test disabled
1 Loopback self test enabled
4
LISTEN
Listen Only Mode — This bit configures the MSCAN as a CAN bus monitor. When LISTEN is set, all valid CAN
messages with matching ID are received, but no acknowledgement or error frames are sent out (see
Section 11.4.4.4, “Listen-Only Mode”). In addition, the error counters are frozen. Listen only mode supports
applications which require “hot plugging” or throughput analysis. The MSCAN is unable to transmit any
messages when listen only mode is active.
0 Normal operation
1 Listen only mode activated
3
BORM
Bus-Off Recovery Mode — This bit configures the bus-off state recovery mode of the MSCAN. Refer to
Section 11.5.2, “Bus-Off Recovery,” for details.
0 Automatic bus-off recovery (see Bosch CAN 2.0A/B protocol specification)
1 Bus-off recovery upon user request
2
WUPM
Wake-Up Mode — If WUPE in CANCTL0 is enabled, this bit defines whether the integrated low-pass filter is
applied to protect the MSCAN from spurious wake-up (see Section 11.4.5.5, “MSCAN Sleep Mode”).
0 MSCAN wakes up on any dominant level on the CAN bus
1 MSCAN wakes up only in case of a dominant pulse on the CAN bus that has a length of Twup
S12XS Family Reference Manual, Rev. 1.10
304
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-4. CANCTL1 Register Field Descriptions (continued)
Field
Description
1
SLPAK
Sleep Mode Acknowledge — This flag indicates whether the MSCAN module has entered sleep mode (see
Section 11.4.5.5, “MSCAN Sleep Mode”). It is used as a handshake flag for the SLPRQ sleep mode request.
Sleep mode is active when SLPRQ = 1 and SLPAK = 1. Depending on the setting of WUPE, the MSCAN will
clear the flag if it detects activity on the CAN bus while in sleep mode.
0 Running — The MSCAN operates normally
1 Sleep mode active — The MSCAN has entered sleep mode
0
INITAK
Initialization Mode Acknowledge — This flag indicates whether the MSCAN module is in initialization mode
(see Section 11.4.4.5, “MSCAN Initialization Mode”). It is used as a handshake flag for the INITRQ initialization
mode request. Initialization mode is active when INITRQ = 1 and INITAK = 1. The registers CANCTL1,
CANBTR0, CANBTR1, CANIDAC, CANIDAR0–CANIDAR7, and CANIDMR0–CANIDMR7 can be written only by
the CPU when the MSCAN is in initialization mode.
0 Running — The MSCAN operates normally
1 Initialization mode active — The MSCAN has entered initialization mode
11.3.2.3
MSCAN Bus Timing Register 0 (CANBTR0)
The CANBTR0 register configures various CAN bus timing parameters of the MSCAN module.
Access: User read/write(1)
Module Base + 0x0002
7
6
5
4
3
2
1
0
SJW1
SJW0
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
0
0
0
0
0
0
0
0
R
W
Reset:
Figure 11-6. MSCAN Bus Timing Register 0 (CANBTR0)
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
Table 11-5. CANBTR0 Register Field Descriptions
Field
Description
7-6
SJW[1:0]
Synchronization Jump Width — The synchronization jump width defines the maximum number of time quanta
(Tq) clock cycles a bit can be shortened or lengthened to achieve resynchronization to data transitions on the
CAN bus (see Table 11-6).
5-0
BRP[5:0]
Baud Rate Prescaler — These bits determine the time quanta (Tq) clock which is used to build up the bit timing
(see Table 11-7).
Table 11-6. Synchronization Jump Width
SJW1
SJW0
Synchronization Jump Width
0
0
1 Tq clock cycle
0
1
2 Tq clock cycles
1
0
3 Tq clock cycles
1
1
4 Tq clock cycles
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
305
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-7. Baud Rate Prescaler
11.3.2.4
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
Prescaler value (P)
0
0
0
0
0
0
1
0
0
0
0
0
1
2
0
0
0
0
1
0
3
0
0
0
0
1
1
4
:
:
:
:
:
:
:
1
1
1
1
1
1
64
MSCAN Bus Timing Register 1 (CANBTR1)
The CANBTR1 register configures various CAN bus timing parameters of the MSCAN module.
Access: User read/write(1)
Module Base + 0x0003
7
6
5
4
3
2
1
0
SAMP
TSEG22
TSEG21
TSEG20
TSEG13
TSEG12
TSEG11
TSEG10
0
0
0
0
0
0
0
0
R
W
Reset:
Figure 11-7. MSCAN Bus Timing Register 1 (CANBTR1)
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
Table 11-8. CANBTR1 Register Field Descriptions
Field
Description
7
SAMP
Sampling — This bit determines the number of CAN bus samples taken per bit time.
0 One sample per bit.
1 Three samples per bit(1).
If SAMP = 0, the resulting bit value is equal to the value of the single bit positioned at the sample point. If
SAMP = 1, the resulting bit value is determined by using majority rule on the three total samples. For higher bit
rates, it is recommended that only one sample is taken per bit time (SAMP = 0).
6-4
Time Segment 2 — Time segments within the bit time fix the number of clock cycles per bit time and the location
TSEG2[2:0] of the sample point (see Figure 11-44). Time segment 2 (TSEG2) values are programmable as shown in
Table 11-9.
3-0
Time Segment 1 — Time segments within the bit time fix the number of clock cycles per bit time and the location
TSEG1[3:0] of the sample point (see Figure 11-44). Time segment 1 (TSEG1) values are programmable as shown in
Table 11-10.
1. In this case, PHASE_SEG1 must be at least 2 time quanta (Tq).
S12XS Family Reference Manual, Rev. 1.10
306
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-9. Time Segment 2 Values
TSEG22
TSEG21
TSEG20
Time Segment 2
0
0
0
1 Tq clock cycle(1)
0
0
1
2 Tq clock cycles
:
:
:
:
1
1
0
7 Tq clock cycles
1
1
1
8 Tq clock cycles
1. This setting is not valid. Please refer to Table 11-37 for valid settings.
Table 11-10. Time Segment 1 Values
TSEG13
TSEG12
TSEG11
TSEG10
Time segment 1
0
0
0
0
1 Tq clock cycle(1)
0
0
0
1
2 Tq clock cycles1
0
0
1
0
3 Tq clock cycles1
0
0
1
1
4 Tq clock cycles
:
:
:
:
:
1
1
1
0
15 Tq clock cycles
1
1
1
1
16 Tq clock cycles
1. This setting is not valid. Please refer to Table 11-37 for valid settings.
The bit time is determined by the oscillator frequency, the baud rate prescaler, and the number of time
quanta (Tq) clock cycles per bit (as shown in Table 11-9 and Table 11-10).
Eqn. 11-1
( Prescaler value )
Bit Time = ------------------------------------------------------ • ( 1 + TimeSegment1 + TimeSegment2 )
f CANCLK
11.3.2.5
MSCAN Receiver Flag Register (CANRFLG)
A flag can be cleared only by software (writing a 1 to the corresponding bit position) when the condition
which caused the setting is no longer valid. Every flag has an associated interrupt enable bit in the
CANRIER register.
Access: User read/write(1)
Module Base + 0x0004
7
6
WUPIF
CSCIF
0
0
R
5
4
3
2
RSTAT1
RSTAT0
TSTAT1
TSTAT0
1
0
OVRIF
RXF
0
0
W
Reset:
0
0
0
0
= Unimplemented
Figure 11-8. MSCAN Receiver Flag Register (CANRFLG)
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
307
Freescale’s Scalable Controller Area Network (S12MSCANV3)
1. Read: Anytime
Write: Anytime when not in initialization mode, except RSTAT[1:0] and TSTAT[1:0] flags which are read-only; write of 1 clears
flag; write of 0 is ignored
NOTE
The CANRFLG register is held in the reset state1 when the initialization
mode is active (INITRQ = 1 and INITAK = 1). This register is writable again
as soon as the initialization mode is exited (INITRQ = 0 and INITAK = 0).
Table 11-11. CANRFLG Register Field Descriptions
Field
Description
7
WUPIF
Wake-Up Interrupt Flag — If the MSCAN detects CAN bus activity while in sleep mode (see Section 11.4.5.5,
“MSCAN Sleep Mode,”) and WUPE = 1 in CANTCTL0 (see Section 11.3.2.1, “MSCAN Control Register 0
(CANCTL0)”), the module will set WUPIF. If not masked, a wake-up interrupt is pending while this flag is set.
0
No wake-up activity observed while in sleep mode
1
MSCAN detected activity on the CAN bus and requested wake-up
6
CSCIF
CAN Status Change Interrupt Flag — This flag is set when the MSCAN changes its current CAN bus status
due to the actual value of the transmit error counter (TEC) and the receive error counter (REC). An additional 4bit (RSTAT[1:0], TSTAT[1:0]) status register, which is split into separate sections for TEC/REC, informs the
system on the actual CAN bus status (see Section 11.3.2.6, “MSCAN Receiver Interrupt Enable Register
(CANRIER)”). If not masked, an error interrupt is pending while this flag is set. CSCIF provides a blocking
interrupt. That guarantees that the receiver/transmitter status bits (RSTAT/TSTAT) are only updated when no
CAN status change interrupt is pending. If the TECs/RECs change their current value after the CSCIF is
asserted, which would cause an additional state change in the RSTAT/TSTAT bits, these bits keep their status
until the current CSCIF interrupt is cleared again.
0
No change in CAN bus status occurred since last interrupt
1
MSCAN changed current CAN bus status
5-4
RSTAT[1:0]
Receiver Status Bits — The values of the error counters control the actual CAN bus status of the MSCAN. As
soon as the status change interrupt flag (CSCIF) is set, these bits indicate the appropriate receiver related CAN
bus status of the MSCAN. The coding for the bits RSTAT1, RSTAT0 is:
00
RxOK: 0 ≤ receive error counter ≤ 96
01
RxWRN: 96 < receive error counter ≤ 127
10
RxERR: 127 < receive error counter
11
Bus-off(1): transmit error counter > 255
3-2
TSTAT[1:0]
Transmitter Status Bits — The values of the error counters control the actual CAN bus status of the MSCAN.
As soon as the status change interrupt flag (CSCIF) is set, these bits indicate the appropriate transmitter related
CAN bus status of the MSCAN. The coding for the bits TSTAT1, TSTAT0 is:
00
TxOK: 0 ≤ transmit error counter ≤ 96
01
TxWRN: 96 < transmit error counter ≤ 127
10
TxERR: 127 < transmit error counter ≤ 255
11
Bus-Off: transmit error counter > 255
1. The RSTAT[1:0], TSTAT[1:0] bits are not affected by initialization mode.
S12XS Family Reference Manual, Rev. 1.10
308
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-11. CANRFLG Register Field Descriptions (continued)
Field
Description
1
OVRIF
Overrun Interrupt Flag — This flag is set when a data overrun condition occurs. If not masked, an error interrupt
is pending while this flag is set.
0
No data overrun condition
1
A data overrun detected
0
RXF(2)
Receive Buffer Full Flag — RXF is set by the MSCAN when a new message is shifted in the receiver FIFO.
This flag indicates whether the shifted buffer is loaded with a correctly received message (matching identifier,
matching cyclic redundancy code (CRC) and no other errors detected). After the CPU has read that message
from the RxFG buffer in the receiver FIFO, the RXF flag must be cleared to release the buffer. A set RXF flag
prohibits the shifting of the next FIFO entry into the foreground buffer (RxFG). If not masked, a receive interrupt
is pending while this flag is set.
0
No new message available within the RxFG
1
The receiver FIFO is not empty. A new message is available in the RxFG
1. Redundant Information for the most critical CAN bus status which is “bus-off”. This only occurs if the Tx error counter exceeds
a number of 255 errors. Bus-off affects the receiver state. As soon as the transmitter leaves its bus-off state the receiver state
skips to RxOK too. Refer also to TSTAT[1:0] coding in this register.
2. To ensure data integrity, do not read the receive buffer registers while the RXF flag is cleared. For MCUs with dual CPUs,
reading the receive buffer registers while the RXF flag is cleared may result in a CPU fault condition.
11.3.2.6
MSCAN Receiver Interrupt Enable Register (CANRIER)
This register contains the interrupt enable bits for the interrupt flags described in the CANRFLG register.
Access: User read/write(1)
Module Base + 0x0005
7
6
5
4
3
2
1
0
WUPIE
CSCIE
RSTATE1
RSTATE0
TSTATE1
TSTATE0
OVRIE
RXFIE
0
0
0
0
0
0
0
0
R
W
Reset:
Figure 11-9. MSCAN Receiver Interrupt Enable Register (CANRIER)
1. Read: Anytime
Write: Anytime when not in initialization mode
NOTE
The CANRIER register is held in the reset state when the initialization mode
is active (INITRQ=1 and INITAK=1). This register is writable when not in
initialization mode (INITRQ=0 and INITAK=0).
The RSTATE[1:0], TSTATE[1:0] bits are not affected by initialization
mode.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
309
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-12. CANRIER Register Field Descriptions
Field
7
WUPIE(1)
6
CSCIE
Description
Wake-Up Interrupt Enable
0 No interrupt request is generated from this event.
1 A wake-up event causes a Wake-Up interrupt request.
CAN Status Change Interrupt Enable
0 No interrupt request is generated from this event.
1 A CAN Status Change event causes an error interrupt request.
5-4
Receiver Status Change Enable — These RSTAT enable bits control the sensitivity level in which receiver state
RSTATE[1:0] changes are causing CSCIF interrupts. Independent of the chosen sensitivity level the RSTAT flags continue to
indicate the actual receiver state and are only updated if no CSCIF interrupt is pending.
00 Do not generate any CSCIF interrupt caused by receiver state changes.
01 Generate CSCIF interrupt only if the receiver enters or leaves “bus-off” state. Discard other receiver state
changes for generating CSCIF interrupt.
10 Generate CSCIF interrupt only if the receiver enters or leaves “RxErr” or “bus-off”(2) state. Discard other
receiver state changes for generating CSCIF interrupt.
11 Generate CSCIF interrupt on all state changes.
3-2
Transmitter Status Change Enable — These TSTAT enable bits control the sensitivity level in which transmitter
TSTATE[1:0] state changes are causing CSCIF interrupts. Independent of the chosen sensitivity level, the TSTAT flags
continue to indicate the actual transmitter state and are only updated if no CSCIF interrupt is pending.
00 Do not generate any CSCIF interrupt caused by transmitter state changes.
01 Generate CSCIF interrupt only if the transmitter enters or leaves “bus-off” state. Discard other transmitter
state changes for generating CSCIF interrupt.
10 Generate CSCIF interrupt only if the transmitter enters or leaves “TxErr” or “bus-off” state. Discard other
transmitter state changes for generating CSCIF interrupt.
11 Generate CSCIF interrupt on all state changes.
1
OVRIE
Overrun Interrupt Enable
0 No interrupt request is generated from this event.
1 An overrun event causes an error interrupt request.
0
RXFIE
Receiver Full Interrupt Enable
0 No interrupt request is generated from this event.
1 A receive buffer full (successful message reception) event causes a receiver interrupt request.
1. WUPIE and WUPE (see Section 11.3.2.1, “MSCAN Control Register 0 (CANCTL0)”) must both be enabled if the recovery
mechanism from stop or wait is required.
2. Bus-off state is only defined for transmitters by the CAN standard (see Bosch CAN 2.0A/B protocol specification). Because
the only possible state change for the transmitter from bus-off to TxOK also forces the receiver to skip its current state to RxOK,
the coding of the RXSTAT[1:0] flags define an additional bus-off state for the receiver (see Section 11.3.2.5, “MSCAN Receiver
Flag Register (CANRFLG)”).
11.3.2.7
MSCAN Transmitter Flag Register (CANTFLG)
The transmit buffer empty flags each have an associated interrupt enable bit in the CANTIER register.
S12XS Family Reference Manual, Rev. 1.10
310
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Access: User read/write(1)
Module Base + 0x0006
R
7
6
5
4
3
0
0
0
0
0
2
1
0
TXE2
TXE1
TXE0
1
1
1
W
Reset:
0
0
0
0
0
= Unimplemented
Figure 11-10. MSCAN Transmitter Flag Register (CANTFLG)
1. Read: Anytime
Write: Anytime when not in initialization mode; write of 1 clears flag, write of 0 is ignored
NOTE
The CANTFLG register is held in the reset state when the initialization
mode is active (INITRQ = 1 and INITAK = 1). This register is writable when
not in initialization mode (INITRQ = 0 and INITAK = 0).
Table 11-13. CANTFLG Register Field Descriptions
Field
Description
2-0
TXE[2:0]
Transmitter Buffer Empty — This flag indicates that the associated transmit message buffer is empty, and thus
not scheduled for transmission. The CPU must clear the flag after a message is set up in the transmit buffer and
is due for transmission. The MSCAN sets the flag after the message is sent successfully. The flag is also set by
the MSCAN when the transmission request is successfully aborted due to a pending abort request (see
Section 11.3.2.9, “MSCAN Transmitter Message Abort Request Register (CANTARQ)”). If not masked, a
transmit interrupt is pending while this flag is set.
Clearing a TXEx flag also clears the corresponding ABTAKx (see Section 11.3.2.10, “MSCAN Transmitter
Message Abort Acknowledge Register (CANTAAK)”). When a TXEx flag is set, the corresponding ABTRQx bit
is cleared (see Section 11.3.2.9, “MSCAN Transmitter Message Abort Request Register (CANTARQ)”).
When listen-mode is active (see Section 11.3.2.2, “MSCAN Control Register 1 (CANCTL1)”) the TXEx flags
cannot be cleared and no transmission is started.
Read and write accesses to the transmit buffer will be blocked, if the corresponding TXEx bit is cleared
(TXEx = 0) and the buffer is scheduled for transmission.
0 The associated message buffer is full (loaded with a message due for transmission)
1 The associated message buffer is empty (not scheduled)
11.3.2.8
MSCAN Transmitter Interrupt Enable Register (CANTIER)
This register contains the interrupt enable bits for the transmit buffer empty interrupt flags.
Access: User read/write(1)
Module Base + 0x0007
R
7
6
5
4
3
0
0
0
0
0
2
1
0
TXEIE2
TXEIE1
TXEIE0
0
0
0
W
Reset:
0
0
0
0
0
= Unimplemented
Figure 11-11. MSCAN Transmitter Interrupt Enable Register (CANTIER)
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
311
Freescale’s Scalable Controller Area Network (S12MSCANV3)
1. Read: Anytime
Write: Anytime when not in initialization mode
NOTE
The CANTIER register is held in the reset state when the initialization mode
is active (INITRQ = 1 and INITAK = 1). This register is writable when not
in initialization mode (INITRQ = 0 and INITAK = 0).
Table 11-14. CANTIER Register Field Descriptions
Field
Description
2-0
TXEIE[2:0]
11.3.2.9
Transmitter Empty Interrupt Enable
0 No interrupt request is generated from this event.
1 A transmitter empty (transmit buffer available for transmission) event causes a transmitter empty interrupt
request.
MSCAN Transmitter Message Abort Request Register (CANTARQ)
The CANTARQ register allows abort request of queued messages as described below.
Access: User read/write(1)
Module Base + 0x0008
R
7
6
5
4
3
0
0
0
0
0
2
1
0
ABTRQ2
ABTRQ1
ABTRQ0
0
0
0
W
Reset:
0
0
0
0
0
= Unimplemented
Figure 11-12. MSCAN Transmitter Message Abort Request Register (CANTARQ)
1. Read: Anytime
Write: Anytime when not in initialization mode
NOTE
The CANTARQ register is held in the reset state when the initialization
mode is active (INITRQ = 1 and INITAK = 1). This register is writable when
not in initialization mode (INITRQ = 0 and INITAK = 0).
Table 11-15. CANTARQ Register Field Descriptions
Field
Description
2-0
Abort Request — The CPU sets the ABTRQx bit to request that a scheduled message buffer (TXEx = 0) be
ABTRQ[2:0] aborted. The MSCAN grants the request if the message has not already started transmission, or if the
transmission is not successful (lost arbitration or error). When a message is aborted, the associated TXE (see
Section 11.3.2.7, “MSCAN Transmitter Flag Register (CANTFLG)”) and abort acknowledge flags (ABTAK, see
Section 11.3.2.10, “MSCAN Transmitter Message Abort Acknowledge Register (CANTAAK)”) are set and a
transmit interrupt occurs if enabled. The CPU cannot reset ABTRQx. ABTRQx is reset whenever the associated
TXE flag is set.
0 No abort request
1 Abort request pending
S12XS Family Reference Manual, Rev. 1.10
312
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.3.2.10 MSCAN Transmitter Message Abort Acknowledge Register (CANTAAK)
The CANTAAK register indicates the successful abort of a queued message, if requested by the
appropriate bits in the CANTARQ register.
Access: User read/write(1)
Module Base + 0x0009
R
7
6
5
4
3
2
1
0
0
0
0
0
0
ABTAK2
ABTAK1
ABTAK0
0
0
0
0
0
0
0
0
W
Reset:
= Unimplemented
Figure 11-13. MSCAN Transmitter Message Abort Acknowledge Register (CANTAAK)
1. Read: Anytime
Write: Unimplemented
NOTE
The CANTAAK register is held in the reset state when the initialization
mode is active (INITRQ = 1 and INITAK = 1).
Table 11-16. CANTAAK Register Field Descriptions
Field
Description
2-0
Abort Acknowledge — This flag acknowledges that a message was aborted due to a pending abort request
ABTAK[2:0] from the CPU. After a particular message buffer is flagged empty, this flag can be used by the application
software to identify whether the message was aborted successfully or was sent anyway. The ABTAKx flag is
cleared whenever the corresponding TXE flag is cleared.
0 The message was not aborted.
1 The message was aborted.
11.3.2.11 MSCAN Transmit Buffer Selection Register (CANTBSEL)
The CANTBSEL register allows the selection of the actual transmit message buffer, which then will be
accessible in the CANTXFG register space.
Access: User read/write(1)
Module Base + 0x000A
R
7
6
5
4
3
0
0
0
0
0
2
1
0
TX2
TX1
TX0
0
0
0
W
Reset:
0
0
0
0
0
= Unimplemented
Figure 11-14. MSCAN Transmit Buffer Selection Register (CANTBSEL)
1. Read: Find the lowest ordered bit set to 1, all other bits will be read as 0
Write: Anytime when not in initialization mode
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
313
Freescale’s Scalable Controller Area Network (S12MSCANV3)
NOTE
The CANTBSEL register is held in the reset state when the initialization
mode is active (INITRQ = 1 and INITAK=1). This register is writable when
not in initialization mode (INITRQ = 0 and INITAK = 0).
Table 11-17. CANTBSEL Register Field Descriptions
Field
Description
2-0
TX[2:0]
Transmit Buffer Select — The lowest numbered bit places the respective transmit buffer in the CANTXFG
register space (e.g., TX1 = 1 and TX0 = 1 selects transmit buffer TX0; TX1 = 1 and TX0 = 0 selects transmit
buffer TX1). Read and write accesses to the selected transmit buffer will be blocked, if the corresponding TXEx
bit is cleared and the buffer is scheduled for transmission (see Section 11.3.2.7, “MSCAN Transmitter Flag
Register (CANTFLG)”).
0 The associated message buffer is deselected
1 The associated message buffer is selected, if lowest numbered bit
The following gives a short programming example of the usage of the CANTBSEL register:
To get the next available transmit buffer, application software must read the CANTFLG register and write
this value back into the CANTBSEL register. In this example Tx buffers TX1 and TX2 are available. The
value read from CANTFLG is therefore 0b0000_0110. When writing this value back to CANTBSEL, the
Tx buffer TX1 is selected in the CANTXFG because the lowest numbered bit set to 1 is at bit position 1.
Reading back this value out of CANTBSEL results in 0b0000_0010, because only the lowest numbered
bit position set to 1 is presented. This mechanism eases the application software’s selection of the next
available Tx buffer.
• LDAA CANTFLG; value read is 0b0000_0110
• STAA CANTBSEL; value written is 0b0000_0110
• LDAA CANTBSEL; value read is 0b0000_0010
If all transmit message buffers are deselected, no accesses are allowed to the CANTXFG registers.
11.3.2.12 MSCAN Identifier Acceptance Control Register (CANIDAC)
The CANIDAC register is used for identifier acceptance control as described below.
Access: User read/write(1)
Module Base + 0x000B
R
7
6
0
0
5
4
IDAM1
IDAM0
0
0
3
2
1
0
0
IDHIT2
IDHIT1
IDHIT0
0
0
0
0
W
Reset:
0
0
= Unimplemented
Figure 11-15. MSCAN Identifier Acceptance Control Register (CANIDAC)
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1), except bits IDHITx, which are read-only
S12XS Family Reference Manual, Rev. 1.10
314
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-18. CANIDAC Register Field Descriptions
Field
Description
5-4
IDAM[1:0]
Identifier Acceptance Mode — The CPU sets these flags to define the identifier acceptance filter organization
(see Section 11.4.3, “Identifier Acceptance Filter”). Table 11-19 summarizes the different settings. In filter closed
mode, no message is accepted such that the foreground buffer is never reloaded.
2-0
IDHIT[2:0]
Identifier Acceptance Hit Indicator — The MSCAN sets these flags to indicate an identifier acceptance hit (see
Section 11.4.3, “Identifier Acceptance Filter”). Table 11-20 summarizes the different settings.
Table 11-19. Identifier Acceptance Mode Settings
IDAM1
IDAM0
Identifier Acceptance Mode
0
0
Two 32-bit acceptance filters
0
1
Four 16-bit acceptance filters
1
0
Eight 8-bit acceptance filters
1
1
Filter closed
Table 11-20. Identifier Acceptance Hit Indication
IDHIT2
IDHIT1
IDHIT0
Identifier Acceptance Hit
0
0
0
Filter 0 hit
0
0
1
Filter 1 hit
0
1
0
Filter 2 hit
0
1
1
Filter 3 hit
1
0
0
Filter 4 hit
1
0
1
Filter 5 hit
1
1
0
Filter 6 hit
1
1
1
Filter 7 hit
The IDHITx indicators are always related to the message in the foreground buffer (RxFG). When a
message gets shifted into the foreground buffer of the receiver FIFO the indicators are updated as well.
11.3.2.13 MSCAN Reserved Register
This register is reserved for factory testing of the MSCAN module and is not available in normal system
operating modes.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
315
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Access: User read/write(1)
Module Base + 0x000C to Module Base + 0x000D
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset:
= Unimplemented
Figure 11-16. MSCAN Reserved Register
1. Read: Always reads zero in normal system operation modes
Write: Unimplemented in normal system operation modes
NOTE
Writing to this register when in special system operating modes can alter the
MSCAN functionality.
11.3.2.14 MSCAN Miscellaneous Register (CANMISC)
This register provides additional features.
Access: User read/write(1)
Module Base + 0x000D
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
BOHOLD
W
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 11-17. MSCAN Miscellaneous Register (CANMISC)
1. Read: Anytime
Write: Anytime; write of ‘1’ clears flag; write of ‘0’ ignored
Table 11-21. CANMISC Register Field Descriptions
Field
Description
0
BOHOLD
Bus-off State Hold Until User Request — If BORM is set in MSCAN Control Register 1 (CANCTL1), this bit
indicates whether the module has entered the bus-off state. Clearing this bit requests the recovery from bus-off.
Refer to Section 11.5.2, “Bus-Off Recovery,” for details.
0 Module is not bus-off or recovery has been requested by user in bus-off state
1 Module is bus-off and holds this state until user request
11.3.2.15 MSCAN Receive Error Counter (CANRXERR)
This register reflects the status of the MSCAN receive error counter.
S12XS Family Reference Manual, Rev. 1.10
316
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Access: User read/write(1)
Module Base + 0x000E
R
7
6
5
4
3
2
1
0
RXERR7
RXERR6
RXERR5
RXERR4
RXERR3
RXERR2
RXERR1
RXERR0
0
0
0
0
0
0
0
0
W
Reset:
= Unimplemented
Figure 11-18. MSCAN Receive Error Counter (CANRXERR)
1. Read: Only when in sleep mode (SLPRQ = 1 and SLPAK = 1) or initialization mode (INITRQ = 1 and INITAK = 1)
Write: Unimplemented
NOTE
Reading this register when in any other mode other than sleep or
initialization mode may return an incorrect value. For MCUs with dual
CPUs, this may result in a CPU fault condition.
Writing to this register when in special modes can alter the MSCAN
functionality.
11.3.2.16 MSCAN Transmit Error Counter (CANTXERR)
This register reflects the status of the MSCAN transmit error counter.
Access: User read/write(1)
Module Base + 0x000F
R
7
6
5
4
3
2
1
0
TXERR7
TXERR6
TXERR5
TXERR4
TXERR3
TXERR2
TXERR1
TXERR0
0
0
0
0
0
0
0
0
W
Reset:
= Unimplemented
Figure 11-19. MSCAN Transmit Error Counter (CANTXERR)
1. Read: Only when in sleep mode (SLPRQ = 1 and SLPAK = 1) or initialization mode (INITRQ = 1 and INITAK = 1)
Write: Unimplemented
NOTE
Reading this register when in any other mode other than sleep or
initialization mode, may return an incorrect value. For MCUs with dual
CPUs, this may result in a CPU fault condition.
Writing to this register when in special modes can alter the MSCAN
functionality.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
317
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.3.2.17 MSCAN Identifier Acceptance Registers (CANIDAR0-7)
On reception, each message is written into the background receive buffer. The CPU is only signalled to
read the message if it passes the criteria in the identifier acceptance and identifier mask registers
(accepted); otherwise, the message is overwritten by the next message (dropped).
The acceptance registers of the MSCAN are applied on the IDR0–IDR3 registers (see Section 11.3.3.1,
“Identifier Registers (IDR0–IDR3)”) of incoming messages in a bit by bit manner (see Section 11.4.3,
“Identifier Acceptance Filter”).
For extended identifiers, all four acceptance and mask registers are applied. For standard identifiers, only
the first two (CANIDAR0/1, CANIDMR0/1) are applied.
Access: User read/write(1)
Module Base + 0x0010 to Module Base + 0x0013
7
6
5
4
3
2
1
0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 11-20. MSCAN Identifier Acceptance Registers (First Bank) — CANIDAR0–CANIDAR3
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
Table 11-22. CANIDAR0–CANIDAR3 Register Field Descriptions
Field
Description
7-0
AC[7:0]
Acceptance Code Bits — AC[7:0] comprise a user-defined sequence of bits with which the corresponding bits
of the related identifier register (IDRn) of the receive message buffer are compared. The result of this comparison
is then masked with the corresponding identifier mask register.
Access: User read/write(1)
Module Base + 0x0018 to Module Base + 0x001B
7
6
5
4
3
2
1
0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 11-21. MSCAN Identifier Acceptance Registers (Second Bank) — CANIDAR4–CANIDAR7
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
S12XS Family Reference Manual, Rev. 1.10
318
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-23. CANIDAR4–CANIDAR7 Register Field Descriptions
Field
Description
7-0
AC[7:0]
Acceptance Code Bits — AC[7:0] comprise a user-defined sequence of bits with which the corresponding bits
of the related identifier register (IDRn) of the receive message buffer are compared. The result of this comparison
is then masked with the corresponding identifier mask register.
11.3.2.18 MSCAN Identifier Mask Registers (CANIDMR0–CANIDMR7)
The identifier mask register specifies which of the corresponding bits in the identifier acceptance register
are relevant for acceptance filtering. To receive standard identifiers in 32 bit filter mode, it is required to
program the last three bits (AM[2:0]) in the mask registers CANIDMR1 and CANIDMR5 to “don’t care.”
To receive standard identifiers in 16 bit filter mode, it is required to program the last three bits (AM[2:0])
in the mask registers CANIDMR1, CANIDMR3, CANIDMR5, and CANIDMR7 to “don’t care.”
Access: User read/write(1)
Module Base + 0x0014 to Module Base + 0x0017
7
6
5
4
3
2
1
0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 11-22. MSCAN Identifier Mask Registers (First Bank) — CANIDMR0–CANIDMR3
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
Table 11-24. CANIDMR0–CANIDMR3 Register Field Descriptions
Field
Description
7-0
AM[7:0]
Acceptance Mask Bits — If a particular bit in this register is cleared, this indicates that the corresponding bit in
the identifier acceptance register must be the same as its identifier bit before a match is detected. The message
is accepted if all such bits match. If a bit is set, it indicates that the state of the corresponding bit in the identifier
acceptance register does not affect whether or not the message is accepted.
0 Match corresponding acceptance code register and identifier bits
1 Ignore corresponding acceptance code register bit
Access: User read/write(1)
Module Base + 0x001C to Module Base + 0x001F
7
6
5
4
3
2
1
0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 11-23. MSCAN Identifier Mask Registers (Second Bank) — CANIDMR4–CANIDMR7
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
319
Freescale’s Scalable Controller Area Network (S12MSCANV3)
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
Table 11-25. CANIDMR4–CANIDMR7 Register Field Descriptions
Field
Description
7-0
AM[7:0]
Acceptance Mask Bits — If a particular bit in this register is cleared, this indicates that the corresponding bit in
the identifier acceptance register must be the same as its identifier bit before a match is detected. The message
is accepted if all such bits match. If a bit is set, it indicates that the state of the corresponding bit in the identifier
acceptance register does not affect whether or not the message is accepted.
0 Match corresponding acceptance code register and identifier bits
1 Ignore corresponding acceptance code register bit
11.3.3
Programmer’s Model of Message Storage
The following section details the organization of the receive and transmit message buffers and the
associated control registers.
To simplify the programmer interface, the receive and transmit message buffers have the same outline.
Each message buffer allocates 16 bytes in the memory map containing a 13 byte data structure.
An additional transmit buffer priority register (TBPR) is defined for the transmit buffers. Within the last
two bytes of this memory map, the MSCAN stores a special 16-bit time stamp, which is sampled from an
internal timer after successful transmission or reception of a message. This feature is only available for
transmit and receiver buffers, if the TIME bit is set (see Section 11.3.2.1, “MSCAN Control Register 0
(CANCTL0)”).
The time stamp register is written by the MSCAN. The CPU can only read these registers.
S12XS Family Reference Manual, Rev. 1.10
320
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-26. Message Buffer Organization
Offset
Address
Register
Access
0x00X0
Identifier Register 0
R/W
0x00X1
Identifier Register 1
R/W
0x00X2
Identifier Register 2
R/W
0x00X3
Identifier Register 3
R/W
0x00X4
Data Segment Register 0
R/W
0x00X5
Data Segment Register 1
R/W
0x00X6
Data Segment Register 2
R/W
0x00X7
Data Segment Register 3
R/W
0x00X8
Data Segment Register 4
R/W
0x00X9
Data Segment Register 5
R/W
0x00XA
Data Segment Register 6
R/W
0x00XB
Data Segment Register 7
R/W
0x00XC
Data Length Register
R/W
(1)
0x00XD
Transmit Buffer Priority Register
R/W
0x00XE
Time Stamp Register (High Byte)
R
0x00XF
Time Stamp Register (Low Byte)
1. Not applicable for receive buffers
R
Figure 11-24 shows the common 13-byte data structure of receive and transmit buffers for extended
identifiers. The mapping of standard identifiers into the IDR registers is shown in Figure 11-25.
All bits of the receive and transmit buffers are ‘x’ out of reset because of RAM-based implementation1.
All reserved or unused bits of the receive and transmit buffers always read ‘x’.
1. Exception: The transmit buffer priority registers are 0 out of reset.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
321
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Figure 11-24. Receive/Transmit Message Buffer — Extended Identifier Mapping
Register
Name
0x00X0
IDR0
0x00X1
IDR1
0x00X2
IDR2
0x00X3
IDR3
0x00X4
DSR0
0x00X5
DSR1
0x00X6
DSR2
0x00X7
DSR3
0x00X8
DSR4
0x00X9
DSR5
0x00XA
DSR6
0x00XB
DSR7
0x00XC
DLR
Bit 7
6
5
4
3
2
1
Bit0
ID28
ID27
ID26
ID25
ID24
ID23
ID22
ID21
ID20
ID19
ID18
SRR (=1)
IDE (=1)
ID17
ID16
ID15
ID14
ID13
ID12
ID11
ID10
ID9
ID8
ID7
ID6
ID5
ID4
ID3
ID2
ID1
ID0
RTR
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DLC3
DLC2
DLC1
DLC0
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
R
W
S12XS Family Reference Manual, Rev. 1.10
322
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Figure 11-24. Receive/Transmit Message Buffer — Extended Identifier Mapping (continued)
Register
Name
Bit 7
6
5
4
3
2
1
Bit0
= Unused, always read ‘x’
Read:
• For transmit buffers, anytime when TXEx flag is set (see Section 11.3.2.7, “MSCAN Transmitter
Flag Register (CANTFLG)”) and the corresponding transmit buffer is selected in CANTBSEL (see
Section 11.3.2.11, “MSCAN Transmit Buffer Selection Register (CANTBSEL)”).
• For receive buffers, only when RXF flag is set (see Section 11.3.2.5, “MSCAN Receiver Flag
Register (CANRFLG)”).
Write:
•
•
For transmit buffers, anytime when TXEx flag is set (see Section 11.3.2.7, “MSCAN Transmitter
Flag Register (CANTFLG)”) and the corresponding transmit buffer is selected in CANTBSEL (see
Section 11.3.2.11, “MSCAN Transmit Buffer Selection Register (CANTBSEL)”).
Unimplemented for receive buffers.
Reset: Undefined because of RAM-based implementation
Figure 11-25. Receive/Transmit Message Buffer — Standard Identifier Mapping
Register
Name
IDR0
0x00X0
IDR1
0x00X1
IDR2
0x00X2
IDR3
0x00X3
Bit 7
6
5
4
3
2
1
Bit 0
ID10
ID9
ID8
ID7
ID6
ID5
ID4
ID3
ID2
ID1
ID0
RTR
IDE (=0)
R
W
R
W
R
W
R
W
= Unused, always read ‘x’
11.3.3.1
Identifier Registers (IDR0–IDR3)
The identifier registers for an extended format identifier consist of a total of 32 bits: ID[28:0], SRR, IDE,
and RTR. The identifier registers for a standard format identifier consist of a total of 13 bits: ID[10:0],
RTR, and IDE.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
323
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.3.3.1.1
IDR0–IDR3 for Extended Identifier Mapping
Module Base + 0x00X0
7
6
5
4
3
2
1
0
ID28
ID27
ID26
ID25
ID24
ID23
ID22
ID21
x
x
x
x
x
x
x
x
R
W
Reset:
Figure 11-26. Identifier Register 0 (IDR0) — Extended Identifier Mapping
Table 11-27. IDR0 Register Field Descriptions — Extended
Field
Description
7-0
ID[28:21]
Extended Format Identifier — The identifiers consist of 29 bits (ID[28:0]) for the extended format. ID28 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number.
Module Base + 0x00X1
7
6
5
4
3
2
1
0
ID20
ID19
ID18
SRR (=1)
IDE (=1)
ID17
ID16
ID15
x
x
x
x
x
x
x
x
R
W
Reset:
Figure 11-27. Identifier Register 1 (IDR1) — Extended Identifier Mapping
Table 11-28. IDR1 Register Field Descriptions — Extended
Field
Description
7-5
ID[20:18]
Extended Format Identifier — The identifiers consist of 29 bits (ID[28:0]) for the extended format. ID28 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number.
4
SRR
Substitute Remote Request — This fixed recessive bit is used only in extended format. It must be set to 1 by
the user for transmission buffers and is stored as received on the CAN bus for receive buffers.
3
IDE
ID Extended — This flag indicates whether the extended or standard identifier format is applied in this buffer. In
the case of a receive buffer, the flag is set as received and indicates to the CPU how to process the buffer
identifier registers. In the case of a transmit buffer, the flag indicates to the MSCAN what type of identifier to send.
0 Standard format (11 bit)
1 Extended format (29 bit)
2-0
ID[17:15]
Extended Format Identifier — The identifiers consist of 29 bits (ID[28:0]) for the extended format. ID28 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number.
S12XS Family Reference Manual, Rev. 1.10
324
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Module Base + 0x00X2
7
6
5
4
3
2
1
0
ID14
ID13
ID12
ID11
ID10
ID9
ID8
ID7
x
x
x
x
x
x
x
x
R
W
Reset:
Figure 11-28. Identifier Register 2 (IDR2) — Extended Identifier Mapping
Table 11-29. IDR2 Register Field Descriptions — Extended
Field
Description
7-0
ID[14:7]
Extended Format Identifier — The identifiers consist of 29 bits (ID[28:0]) for the extended format. ID28 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number.
Module Base + 0x00X3
7
6
5
4
3
2
1
0
ID6
ID5
ID4
ID3
ID2
ID1
ID0
RTR
x
x
x
x
x
x
x
x
R
W
Reset:
Figure 11-29. Identifier Register 3 (IDR3) — Extended Identifier Mapping
Table 11-30. IDR3 Register Field Descriptions — Extended
Field
Description
7-1
ID[6:0]
Extended Format Identifier — The identifiers consist of 29 bits (ID[28:0]) for the extended format. ID28 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number.
0
RTR
Remote Transmission Request — This flag reflects the status of the remote transmission request bit in the
CAN frame. In the case of a receive buffer, it indicates the status of the received frame and supports the
transmission of an answering frame in software. In the case of a transmit buffer, this flag defines the setting of
the RTR bit to be sent.
0 Data frame
1 Remote frame
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
325
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.3.3.1.2
IDR0–IDR3 for Standard Identifier Mapping
Module Base + 0x00X0
7
6
5
4
3
2
1
0
ID10
ID9
ID8
ID7
ID6
ID5
ID4
ID3
x
x
x
x
x
x
x
x
R
W
Reset:
Figure 11-30. Identifier Register 0 — Standard Mapping
Table 11-31. IDR0 Register Field Descriptions — Standard
Field
Description
7-0
ID[10:3]
Standard Format Identifier — The identifiers consist of 11 bits (ID[10:0]) for the standard format. ID10 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number. See also ID bits in Table 11-32.
Module Base + 0x00X1
7
6
5
4
3
ID2
ID1
ID0
RTR
IDE (=0)
x
x
x
x
x
2
1
0
x
x
x
R
W
Reset:
= Unused; always read ‘x’
Figure 11-31. Identifier Register 1 — Standard Mapping
Table 11-32. IDR1 Register Field Descriptions
Field
Description
7-5
ID[2:0]
Standard Format Identifier — The identifiers consist of 11 bits (ID[10:0]) for the standard format. ID10 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number. See also ID bits in Table 11-31.
4
RTR
Remote Transmission Request — This flag reflects the status of the Remote Transmission Request bit in the
CAN frame. In the case of a receive buffer, it indicates the status of the received frame and supports the
transmission of an answering frame in software. In the case of a transmit buffer, this flag defines the setting of
the RTR bit to be sent.
0 Data frame
1 Remote frame
3
IDE
ID Extended — This flag indicates whether the extended or standard identifier format is applied in this buffer. In
the case of a receive buffer, the flag is set as received and indicates to the CPU how to process the buffer
identifier registers. In the case of a transmit buffer, the flag indicates to the MSCAN what type of identifier to send.
0 Standard format (11 bit)
1 Extended format (29 bit)
S12XS Family Reference Manual, Rev. 1.10
326
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Module Base + 0x00X2
7
6
5
4
3
2
1
0
x
x
x
x
x
x
x
x
R
W
Reset:
= Unused; always read ‘x’
Figure 11-32. Identifier Register 2 — Standard Mapping
Module Base + 0x00X3
7
6
5
4
3
2
1
0
x
x
x
x
x
x
x
x
R
W
Reset:
= Unused; always read ‘x’
Figure 11-33. Identifier Register 3 — Standard Mapping
11.3.3.2
Data Segment Registers (DSR0-7)
The eight data segment registers, each with bits DB[7:0], contain the data to be transmitted or received.
The number of bytes to be transmitted or received is determined by the data length code in the
corresponding DLR register.
Module Base + 0x00X4 to Module Base + 0x00XB
7
6
5
4
3
2
1
0
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
x
x
x
x
x
x
x
x
R
W
Reset:
Figure 11-34. Data Segment Registers (DSR0–DSR7) — Extended Identifier Mapping
Table 11-33. DSR0–DSR7 Register Field Descriptions
Field
7-0
DB[7:0]
Description
Data bits 7-0
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
327
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.3.3.3
Data Length Register (DLR)
This register keeps the data length field of the CAN frame.
Module Base + 0x00XC
7
6
5
4
3
2
1
0
DLC3
DLC2
DLC1
DLC0
x
x
x
x
R
W
Reset:
x
x
x
x
= Unused; always read “x”
Figure 11-35. Data Length Register (DLR) — Extended Identifier Mapping
Table 11-34. DLR Register Field Descriptions
Field
Description
3-0
DLC[3:0]
Data Length Code Bits — The data length code contains the number of bytes (data byte count) of the respective
message. During the transmission of a remote frame, the data length code is transmitted as programmed while
the number of transmitted data bytes is always 0. The data byte count ranges from 0 to 8 for a data frame.
Table 11-35 shows the effect of setting the DLC bits.
Table 11-35. Data Length Codes
Data Length Code
11.3.3.4
DLC3
DLC2
DLC1
DLC0
Data Byte
Count
0
0
0
0
0
0
0
0
1
1
0
0
1
0
2
0
0
1
1
3
0
1
0
0
4
0
1
0
1
5
0
1
1
0
6
0
1
1
1
7
1
0
0
0
8
Transmit Buffer Priority Register (TBPR)
This register defines the local priority of the associated message buffer. The local priority is used for the
internal prioritization process of the MSCAN and is defined to be highest for the smallest binary number.
The MSCAN implements the following internal prioritization mechanisms:
• All transmission buffers with a cleared TXEx flag participate in the prioritization immediately
before the SOF (start of frame) is sent.
S12XS Family Reference Manual, Rev. 1.10
328
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
•
The transmission buffer with the lowest local priority field wins the prioritization.
In cases of more than one buffer having the same lowest priority, the message buffer with the lower index
number wins.
Access: User read/write(1)
Module Base + 0x00XD
7
6
5
4
3
2
1
0
PRIO7
PRIO6
PRIO5
PRIO4
PRIO3
PRIO2
PRIO1
PRIO0
0
0
0
0
0
0
0
0
R
W
Reset:
Figure 11-36. Transmit Buffer Priority Register (TBPR)
1. Read: Anytime when TXEx flag is set (see Section 11.3.2.7, “MSCAN Transmitter Flag Register (CANTFLG)”) and the
corresponding transmit buffer is selected in CANTBSEL (see Section 11.3.2.11, “MSCAN Transmit Buffer Selection Register
(CANTBSEL)”)
Write: Anytime when TXEx flag is set (see Section 11.3.2.7, “MSCAN Transmitter Flag Register (CANTFLG)”) and the
corresponding transmit buffer is selected in CANTBSEL (see Section 11.3.2.11, “MSCAN Transmit Buffer Selection Register
(CANTBSEL)”)
11.3.3.5
Time Stamp Register (TSRH–TSRL)
If the TIME bit is enabled, the MSCAN will write a time stamp to the respective registers in the active
transmit or receive buffer right after the EOF of a valid message on the CAN bus (see Section 11.3.2.1,
“MSCAN Control Register 0 (CANCTL0)”). In case of a transmission, the CPU can only read the time
stamp after the respective transmit buffer has been flagged empty.
The timer value, which is used for stamping, is taken from a free running internal CAN bit clock. A timer
overrun is not indicated by the MSCAN. The timer is reset (all bits set to 0) during initialization mode. The
CPU can only read the time stamp registers.
Access: User read/write(1)
Module Base + 0x00XE
R
7
6
5
4
3
2
1
0
TSR15
TSR14
TSR13
TSR12
TSR11
TSR10
TSR9
TSR8
x
x
x
x
x
x
x
x
W
Reset:
Figure 11-37. Time Stamp Register — High Byte (TSRH)
1. Read: Anytime when TXEx flag is set (see Section 11.3.2.7, “MSCAN Transmitter Flag Register (CANTFLG)”) and the
corresponding transmit buffer is selected in CANTBSEL (see Section 11.3.2.11, “MSCAN Transmit Buffer Selection Register
(CANTBSEL)”)
Write: Unimplemented
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
329
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Access: User read/write(1)
Module Base + 0x00XF
R
7
6
5
4
3
2
1
0
TSR7
TSR6
TSR5
TSR4
TSR3
TSR2
TSR1
TSR0
x
x
x
x
x
x
x
x
W
Reset:
Figure 11-38. Time Stamp Register — Low Byte (TSRL)
1. Read: Anytime when TXEx flag is set (see Section 11.3.2.7, “MSCAN Transmitter Flag Register (CANTFLG)”) and the
corresponding transmit buffer is selected in CANTBSEL (see Section 11.3.2.11, “MSCAN Transmit Buffer Selection Register
(CANTBSEL)”)
Write: Unimplemented
S12XS Family Reference Manual, Rev. 1.10
330
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.4
11.4.1
Functional Description
General
This section provides a complete functional description of the MSCAN.
11.4.2
Message Storage
CAN Receive / Transmit Engine
Memory Mapped I/O
Rx0
RXF
CPU bus
RxFG
RxBG
MSCAN
Rx1
Rx2
Rx3
Rx4
Receiver
TxBG
Tx0
MSCAN
TxFG
Tx1
Transmitter
TxBG
Tx2
TXE0
PRIO
TXE1
CPU bus
PRIO
TXE2
PRIO
Figure 11-39. User Model for Message Buffer Organization
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
331
Freescale’s Scalable Controller Area Network (S12MSCANV3)
The MSCAN facilitates a sophisticated message storage system which addresses the requirements of a
broad range of network applications.
11.4.2.1
Message Transmit Background
Modern application layer software is built upon two fundamental assumptions:
• Any CAN node is able to send out a stream of scheduled messages without releasing the CAN bus
between the two messages. Such nodes arbitrate for the CAN bus immediately after sending the
previous message and only release the CAN bus in case of lost arbitration.
• The internal message queue within any CAN node is organized such that the highest priority
message is sent out first, if more than one message is ready to be sent.
The behavior described in the bullets above cannot be achieved with a single transmit buffer. That buffer
must be reloaded immediately after the previous message is sent. This loading process lasts a finite amount
of time and must be completed within the inter-frame sequence (IFS) to be able to send an uninterrupted
stream of messages. Even if this is feasible for limited CAN bus speeds, it requires that the CPU reacts
with short latencies to the transmit interrupt.
A double buffer scheme de-couples the reloading of the transmit buffer from the actual message sending
and, therefore, reduces the reactiveness requirements of the CPU. Problems can arise if the sending of a
message is finished while the CPU re-loads the second buffer. No buffer would then be ready for
transmission, and the CAN bus would be released.
At least three transmit buffers are required to meet the first of the above requirements under all
circumstances. The MSCAN has three transmit buffers.
The second requirement calls for some sort of internal prioritization which the MSCAN implements with
the “local priority” concept described in Section 11.4.2.2, “Transmit Structures.”
11.4.2.2
Transmit Structures
The MSCAN triple transmit buffer scheme optimizes real-time performance by allowing multiple
messages to be set up in advance. The three buffers are arranged as shown in Figure 11-39.
All three buffers have a 13-byte data structure similar to the outline of the receive buffers (see
Section 11.3.3, “Programmer’s Model of Message Storage”). An additional Transmit Buffer Priority
Register (TBPR) contains an 8-bit local priority field (PRIO) (see Section 11.3.3.4, “Transmit Buffer
Priority Register (TBPR)”). The remaining two bytes are used for time stamping of a message, if required
(see Section 11.3.3.5, “Time Stamp Register (TSRH–TSRL)”).
To transmit a message, the CPU must identify an available transmit buffer, which is indicated by a set
transmitter buffer empty (TXEx) flag (see Section 11.3.2.7, “MSCAN Transmitter Flag Register
(CANTFLG)”). If a transmit buffer is available, the CPU must set a pointer to this buffer by writing to the
CANTBSEL register (see Section 11.3.2.11, “MSCAN Transmit Buffer Selection Register
(CANTBSEL)”). This makes the respective buffer accessible within the CANTXFG address space (see
Section 11.3.3, “Programmer’s Model of Message Storage”). The algorithmic feature associated with the
CANTBSEL register simplifies the transmit buffer selection. In addition, this scheme makes the handler
S12XS Family Reference Manual, Rev. 1.10
332
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
software simpler because only one address area is applicable for the transmit process, and the required
address space is minimized.
The CPU then stores the identifier, the control bits, and the data content into one of the transmit buffers.
Finally, the buffer is flagged as ready for transmission by clearing the associated TXE flag.
The MSCAN then schedules the message for transmission and signals the successful transmission of the
buffer by setting the associated TXE flag. A transmit interrupt (see Section 11.4.7.2, “Transmit Interrupt”)
is generated1 when TXEx is set and can be used to drive the application software to re-load the buffer.
If more than one buffer is scheduled for transmission when the CAN bus becomes available for arbitration,
the MSCAN uses the local priority setting of the three buffers to determine the prioritization. For this
purpose, every transmit buffer has an 8-bit local priority field (PRIO). The application software programs
this field when the message is set up. The local priority reflects the priority of this particular message
relative to the set of messages being transmitted from this node. The lowest binary value of the PRIO field
is defined to be the highest priority. The internal scheduling process takes place whenever the MSCAN
arbitrates for the CAN bus. This is also the case after the occurrence of a transmission error.
When a high priority message is scheduled by the application software, it may become necessary to abort
a lower priority message in one of the three transmit buffers. Because messages that are already in
transmission cannot be aborted, the user must request the abort by setting the corresponding abort request
bit (ABTRQ) (see Section 11.3.2.9, “MSCAN Transmitter Message Abort Request Register
(CANTARQ)”.) The MSCAN then grants the request, if possible, by:
1. Setting the corresponding abort acknowledge flag (ABTAK) in the CANTAAK register.
2. Setting the associated TXE flag to release the buffer.
3. Generating a transmit interrupt. The transmit interrupt handler software can determine from the
setting of the ABTAK flag whether the message was aborted (ABTAK = 1) or sent (ABTAK = 0).
11.4.2.3
Receive Structures
The received messages are stored in a five stage input FIFO. The five message buffers are alternately
mapped into a single memory area (see Figure 11-39). The background receive buffer (RxBG) is
exclusively associated with the MSCAN, but the foreground receive buffer (RxFG) is addressable by the
CPU (see Figure 11-39). This scheme simplifies the handler software because only one address area is
applicable for the receive process.
All receive buffers have a size of 15 bytes to store the CAN control bits, the identifier (standard or
extended), the data contents, and a time stamp, if enabled (see Section 11.3.3, “Programmer’s Model of
Message Storage”).
The receiver full flag (RXF) (see Section 11.3.2.5, “MSCAN Receiver Flag Register (CANRFLG)”)
signals the status of the foreground receive buffer. When the buffer contains a correctly received message
with a matching identifier, this flag is set.
On reception, each message is checked to see whether it passes the filter (see Section 11.4.3, “Identifier
Acceptance Filter”) and simultaneously is written into the active RxBG. After successful reception of a
valid message, the MSCAN shifts the content of RxBG into the receiver FIFO, sets the RXF flag, and
1. The transmit interrupt occurs only if not masked. A polling scheme can be applied on TXEx also.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
333
Freescale’s Scalable Controller Area Network (S12MSCANV3)
generates a receive interrupt1 (see Section 11.4.7.3, “Receive Interrupt”) to the CPU. The user’s receive
handler must read the received message from the RxFG and then reset the RXF flag to acknowledge the
interrupt and to release the foreground buffer. A new message, which can follow immediately after the IFS
field of the CAN frame, is received into the next available RxBG. If the MSCAN receives an invalid
message in its RxBG (wrong identifier, transmission errors, etc.) the actual contents of the buffer will be
over-written by the next message. The buffer will then not be shifted into the FIFO.
When the MSCAN module is transmitting, the MSCAN receives its own transmitted messages into the
background receive buffer, RxBG, but does not shift it into the receiver FIFO, generate a receive interrupt,
or acknowledge its own messages on the CAN bus. The exception to this rule is in loopback mode (see
Section 11.3.2.2, “MSCAN Control Register 1 (CANCTL1)”) where the MSCAN treats its own messages
exactly like all other incoming messages. The MSCAN receives its own transmitted messages in the event
that it loses arbitration. If arbitration is lost, the MSCAN must be prepared to become a receiver.
An overrun condition occurs when all receive message buffers in the FIFO are filled with correctly
received messages with accepted identifiers and another message is correctly received from the CAN bus
with an accepted identifier. The latter message is discarded and an error interrupt with overrun indication
is generated if enabled (see Section 11.4.7.5, “Error Interrupt”). The MSCAN remains able to transmit
messages while the receiver FIFO is being filled, but all incoming messages are discarded. As soon as a
receive buffer in the FIFO is available again, new valid messages will be accepted.
11.4.3
Identifier Acceptance Filter
The MSCAN identifier acceptance registers (see Section 11.3.2.12, “MSCAN Identifier Acceptance
Control Register (CANIDAC)”) define the acceptable patterns of the standard or extended identifier
(ID[10:0] or ID[28:0]). Any of these bits can be marked ‘don’t care’ in the MSCAN identifier mask
registers (see Section 11.3.2.18, “MSCAN Identifier Mask Registers (CANIDMR0–CANIDMR7)”).
A filter hit is indicated to the application software by a set receive buffer full flag (RXF = 1) and three bits
in the CANIDAC register (see Section 11.3.2.12, “MSCAN Identifier Acceptance Control Register
(CANIDAC)”). These identifier hit flags (IDHIT[2:0]) clearly identify the filter section that caused the
acceptance. They simplify the application software’s task to identify the cause of the receiver interrupt. If
more than one hit occurs (two or more filters match), the lower hit has priority.
A very flexible programmable generic identifier acceptance filter has been introduced to reduce the CPU
interrupt loading. The filter is programmable to operate in four different modes:
• Two identifier acceptance filters, each to be applied to:
— The full 29 bits of the extended identifier and to the following bits of the CAN 2.0B frame:
– Remote transmission request (RTR)
– Identifier extension (IDE)
– Substitute remote request (SRR)
— The 11 bits of the standard identifier plus the RTR and IDE bits of the CAN 2.0A/B messages.
This mode implements two filters for a full length CAN 2.0B compliant extended identifier.
Although this mode can be used for standard identifiers, it is recommended to use the four or
eight identifier acceptance filters.
1. The receive interrupt occurs only if not masked. A polling scheme can be applied on RXF also.
S12XS Family Reference Manual, Rev. 1.10
334
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
•
•
•
Figure 11-40 shows how the first 32-bit filter bank (CANIDAR0–CANIDAR3,
CANIDMR0–CANIDMR3) produces a filter 0 hit. Similarly, the second filter bank
(CANIDAR4–CANIDAR7, CANIDMR4–CANIDMR7) produces a filter 1 hit.
Four identifier acceptance filters, each to be applied to:
— The 14 most significant bits of the extended identifier plus the SRR and IDE bits of CAN 2.0B
messages.
— The 11 bits of the standard identifier, the RTR and IDE bits of CAN 2.0A/B messages.
Figure 11-41 shows how the first 32-bit filter bank (CANIDAR0–CANIDA3,
CANIDMR0–3CANIDMR) produces filter 0 and 1 hits. Similarly, the second filter bank
(CANIDAR4–CANIDAR7, CANIDMR4–CANIDMR7) produces filter 2 and 3 hits.
Eight identifier acceptance filters, each to be applied to the first 8 bits of the identifier. This mode
implements eight independent filters for the first 8 bits of a CAN 2.0A/B compliant standard
identifier or a CAN 2.0B compliant extended identifier.
Figure 11-42 shows how the first 32-bit filter bank (CANIDAR0–CANIDAR3,
CANIDMR0–CANIDMR3) produces filter 0 to 3 hits. Similarly, the second filter bank
(CANIDAR4–CANIDAR7, CANIDMR4–CANIDMR7) produces filter 4 to 7 hits.
Closed filter. No CAN message is copied into the foreground buffer RxFG, and the RXF flag is
never set.
CAN 2.0B
Extended Identifier ID28
IDR0
ID21
ID20
IDR1
CAN 2.0A/B
Standard Identifier ID10
IDR0
ID3
ID2
IDR1
ID15
IDE
ID14
IDR2
ID7
ID6
IDR3
RTR
ID10
IDR2
ID3
ID10
IDR3
ID3
AM7
CANIDMR0
AM0
AM7
CANIDMR1
AM0
AM7
CANIDMR2
AM0
AM7
CANIDMR3
AM0
AC7
CANIDAR0
AC0
AC7
CANIDAR1
AC0
AC7
CANIDAR2
AC0
AC7
CANIDAR3
AC0
ID Accepted (Filter 0 Hit)
Figure 11-40. 32-bit Maskable Identifier Acceptance Filter
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
335
Freescale’s Scalable Controller Area Network (S12MSCANV3)
CAN 2.0B
Extended Identifier
ID28
IDR0
ID21
ID20
IDR1
CAN 2.0A/B
Standard Identifier
ID10
IDR0
ID3
ID2
IDR1
AM7
CANIDMR0
AM0
AM7
CANIDMR1
AM0
AC7
CANIDAR0
AC0
AC7
CANIDAR1
AC0
ID15
IDE
ID14
IDR2
ID7
ID6
IDR3
RTR
ID10
IDR2
ID3
ID10
IDR3
ID3
ID Accepted (Filter 0 Hit)
AM7
CANIDMR2
AM0
AM7
CANIDMR3
AM0
AC7
CANIDAR2
AC0
AC7
CANIDAR3
AC0
ID Accepted (Filter 1 Hit)
Figure 11-41. 16-bit Maskable Identifier Acceptance Filters
S12XS Family Reference Manual, Rev. 1.10
336
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
CAN 2.0B
Extended Identifier ID28
IDR0
ID21
ID20
IDR1
CAN 2.0A/B
Standard Identifier ID10
IDR0
ID3
ID2
IDR1
AM7
CIDMR0
AM0
AC7
CIDAR0
AC0
ID15
IDE
ID14
IDR2
ID7
ID6
IDR3
RTR
ID10
IDR2
ID3
ID10
IDR3
ID3
ID Accepted (Filter 0 Hit)
AM7
CIDMR1
AM0
AC7
CIDAR1
AC0
ID Accepted (Filter 1 Hit)
AM7
CIDMR2
AM0
AC7
CIDAR2
AC0
ID Accepted (Filter 2 Hit)
AM7
CIDMR3
AM0
AC7
CIDAR3
AC0
ID Accepted (Filter 3 Hit)
Figure 11-42. 8-bit Maskable Identifier Acceptance Filters
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
337
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.4.3.1
Protocol Violation Protection
The MSCAN protects the user from accidentally violating the CAN protocol through programming errors.
The protection logic implements the following features:
• The receive and transmit error counters cannot be written or otherwise manipulated.
• All registers which control the configuration of the MSCAN cannot be modified while the MSCAN
is on-line. The MSCAN has to be in Initialization Mode. The corresponding INITRQ/INITAK
handshake bits in the CANCTL0/CANCTL1 registers (see Section 11.3.2.1, “MSCAN Control
Register 0 (CANCTL0)”) serve as a lock to protect the following registers:
— MSCAN control 1 register (CANCTL1)
— MSCAN bus timing registers 0 and 1 (CANBTR0, CANBTR1)
— MSCAN identifier acceptance control register (CANIDAC)
— MSCAN identifier acceptance registers (CANIDAR0–CANIDAR7)
— MSCAN identifier mask registers (CANIDMR0–CANIDMR7)
• The TXCAN is immediately forced to a recessive state when the MSCAN goes into the power
down mode or initialization mode (see Section 11.4.5.6, “MSCAN Power Down Mode,” and
Section 11.4.4.5, “MSCAN Initialization Mode”).
• The MSCAN enable bit (CANE) is writable only once in normal system operation modes, which
provides further protection against inadvertently disabling the MSCAN.
11.4.3.2
Clock System
Figure 11-43 shows the structure of the MSCAN clock generation circuitry.
MSCAN
Bus Clock
CANCLK
CLKSRC
Prescaler
(1 .. 64)
Time quanta clock (Tq)
CLKSRC
Oscillator Clock
Figure 11-43. MSCAN Clocking Scheme
The clock source bit (CLKSRC) in the CANCTL1 register (11.3.2.2/11-303) defines whether the internal
CANCLK is connected to the output of a crystal oscillator (oscillator clock) or to the bus clock.
The clock source has to be chosen such that the tight oscillator tolerance requirements (up to 0.4%) of the
CAN protocol are met. Additionally, for high CAN bus rates (1 Mbps), a 45% to 55% duty cycle of the
clock is required.
If the bus clock is generated from a PLL, it is recommended to select the oscillator clock rather than the
bus clock due to jitter considerations, especially at the faster CAN bus rates.
S12XS Family Reference Manual, Rev. 1.10
338
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
For microcontrollers without a clock and reset generator (CRG), CANCLK is driven from the crystal
oscillator (oscillator clock).
A programmable prescaler generates the time quanta (Tq) clock from CANCLK. A time quantum is the
atomic unit of time handled by the MSCAN.
Eqn. 11-2
f CANCLK
=
----------------------------------------------------Tq ( Prescaler value -)
A bit time is subdivided into three segments as described in the Bosch CAN specification. (see Figure 1144):
• SYNC_SEG: This segment has a fixed length of one time quantum. Signal edges are expected to
happen within this section.
• Time Segment 1: This segment includes the PROP_SEG and the PHASE_SEG1 of the CAN
standard. It can be programmed by setting the parameter TSEG1 to consist of 4 to 16 time quanta.
• Time Segment 2: This segment represents the PHASE_SEG2 of the CAN standard. It can be
programmed by setting the TSEG2 parameter to be 2 to 8 time quanta long.
Eqn. 11-3
f Tq
Bit Rate = --------------------------------------------------------------------------------( number of Time Quanta )
NRZ Signal
SYNC_SEG
Time Segment 1
(PROP_SEG + PHASE_SEG1)
Time Segment 2
(PHASE_SEG2)
1
4 ... 16
2 ... 8
8 ... 25 Time Quanta
= 1 Bit Time
Transmit Point
Sample Point
(single or triple sampling)
Figure 11-44. Segments within the Bit Time
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
339
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-36. Time Segment Syntax
Syntax
Description
System expects transitions to occur on the CAN bus during this
period.
SYNC_SEG
Transmit Point
A node in transmit mode transfers a new value to the CAN bus at
this point.
Sample Point
A node in receive mode samples the CAN bus at this point. If the
three samples per bit option is selected, then this point marks the
position of the third sample.
The synchronization jump width (see the Bosch CAN specification for details) can be programmed in a
range of 1 to 4 time quanta by setting the SJW parameter.
The SYNC_SEG, TSEG1, TSEG2, and SJW parameters are set by programming the MSCAN bus timing
registers (CANBTR0, CANBTR1) (see Section 11.3.2.3, “MSCAN Bus Timing Register 0 (CANBTR0)”
and Section 11.3.2.4, “MSCAN Bus Timing Register 1 (CANBTR1)”).
Table 11-37 gives an overview of the CAN compliant segment settings and the related parameter values.
NOTE
It is the user’s responsibility to ensure the bit time settings are in compliance
with the CAN standard.
Table 11-37. CAN Standard Compliant Bit Time Segment Settings
Synchronization
Jump Width
Time Segment 1
TSEG1
Time Segment 2
TSEG2
5 .. 10
4 .. 9
2
1
1 .. 2
0 .. 1
4 .. 11
3 .. 10
3
2
1 .. 3
0 .. 2
5 .. 12
4 .. 11
4
3
1 .. 4
0 .. 3
6 .. 13
5 .. 12
5
4
1 .. 4
0 .. 3
7 .. 14
6 .. 13
6
5
1 .. 4
0 .. 3
8 .. 15
7 .. 14
7
6
1 .. 4
0 .. 3
9 .. 16
8 .. 15
8
7
1 .. 4
0 .. 3
11.4.4
11.4.4.1
SJW
Modes of Operation
Normal System Operating Modes
The MSCAN module behaves as described within this specification in all normal system operating modes.
Write restrictions exist for some registers.
S12XS Family Reference Manual, Rev. 1.10
340
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.4.4.2
Special System Operating Modes
The MSCAN module behaves as described within this specification in all special system operating modes.
Write restrictions which exist on specific registers in normal modes are lifted for test purposes in special
modes.
11.4.4.3
Emulation Modes
In all emulation modes, the MSCAN module behaves just like in normal system operating modes as
described within this specification.
11.4.4.4
Listen-Only Mode
In an optional CAN bus monitoring mode (listen-only), the CAN node is able to receive valid data frames
and valid remote frames, but it sends only “recessive” bits on the CAN bus. In addition, it cannot start a
transmission.
If the MAC sub-layer is required to send a “dominant” bit (ACK bit, overload flag, or active error flag), the
bit is rerouted internally so that the MAC sub-layer monitors this “dominant” bit, although the CAN bus
may remain in recessive state externally.
11.4.4.5
MSCAN Initialization Mode
The MSCAN enters initialization mode when it is enabled (CANE=1).
When entering initialization mode during operation, any on-going transmission or reception is
immediately aborted and synchronization to the CAN bus is lost, potentially causing CAN protocol
violations. To protect the CAN bus system from fatal consequences of violations, the MSCAN
immediately drives TXCAN into a recessive state.
NOTE
The user is responsible for ensuring that the MSCAN is not active when
initialization mode is entered. The recommended procedure is to bring the
MSCAN into sleep mode (SLPRQ = 1 and SLPAK = 1) before setting the
INITRQ bit in the CANCTL0 register. Otherwise, the abort of an on-going
message can cause an error condition and can impact other CAN bus
devices.
In initialization mode, the MSCAN is stopped. However, interface registers remain accessible. This mode
is used to reset the CANCTL0, CANRFLG, CANRIER, CANTFLG, CANTIER, CANTARQ,
CANTAAK, and CANTBSEL registers to their default values. In addition, the MSCAN enables the
configuration of the CANBTR0, CANBTR1 bit timing registers; CANIDAC; and the CANIDAR,
CANIDMR message filters. See Section 11.3.2.1, “MSCAN Control Register 0 (CANCTL0),” for a
detailed description of the initialization mode.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
341
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Bus Clock Domain
CAN Clock Domain
INITRQ
SYNC
sync.
INITRQ
sync.
SYNC
INITAK
CPU
Init Request
INITAK
Flag
INITAK
INIT
Flag
Figure 11-45. Initialization Request/Acknowledge Cycle
Due to independent clock domains within the MSCAN, INITRQ must be synchronized to all domains by
using a special handshake mechanism. This handshake causes additional synchronization delay (see
Figure 11-45).
If there is no message transfer ongoing on the CAN bus, the minimum delay will be two additional bus
clocks and three additional CAN clocks. When all parts of the MSCAN are in initialization mode, the
INITAK flag is set. The application software must use INITAK as a handshake indication for the request
(INITRQ) to go into initialization mode.
NOTE
The CPU cannot clear INITRQ before initialization mode (INITRQ = 1 and
INITAK = 1) is active.
11.4.5
Low-Power Options
If the MSCAN is disabled (CANE = 0), the MSCAN clocks are stopped for power saving.
If the MSCAN is enabled (CANE = 1), the MSCAN has two additional modes with reduced power
consumption, compared to normal mode: sleep and power down mode. In sleep mode, power consumption
is reduced by stopping all clocks except those to access the registers from the CPU side. In power down
mode, all clocks are stopped and no power is consumed.
Table 11-38 summarizes the combinations of MSCAN and CPU modes. A particular combination of
modes is entered by the given settings on the CSWAI and SLPRQ/SLPAK bits.
S12XS Family Reference Manual, Rev. 1.10
342
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 11-38. CPU vs. MSCAN Operating Modes
MSCAN Mode
Reduced Power Consumption
CPU Mode
Normal
Sleep
RUN
CSWAI = X(1)
SLPRQ = 0
SLPAK = 0
CSWAI = X
SLPRQ = 1
SLPAK = 1
WAIT
CSWAI = 0
SLPRQ = 0
SLPAK = 0
CSWAI = 0
SLPRQ = 1
SLPAK = 1
STOP
Power Down
Disabled
(CANE=0)
CSWAI = X
SLPRQ = X
SLPAK = X
CSWAI = 1
SLPRQ = X
SLPAK = X
CSWAI = X
SLPRQ = X
SLPAK = X
CSWAI = X
SLPRQ = X
SLPAK = X
CSWAI = X
SLPRQ = X
SLPAK = X
1. ‘X’ means don’t care.
11.4.5.1
Operation in Run Mode
As shown in Table 11-38, only MSCAN sleep mode is available as low power option when the CPU is in
run mode.
11.4.5.2
Operation in Wait Mode
The WAI instruction puts the MCU in a low power consumption stand-by mode. If the CSWAI bit is set,
additional power can be saved in power down mode because the CPU clocks are stopped. After leaving
this power down mode, the MSCAN restarts and enters normal mode again.
While the CPU is in wait mode, the MSCAN can be operated in normal mode and generate interrupts
(registers can be accessed via background debug mode).
11.4.5.3
Operation in Stop Mode
The STOP instruction puts the MCU in a low power consumption stand-by mode. In stop mode, the
MSCAN is set in power down mode regardless of the value of the SLPRQ/SLPAK and CSWAI bits
(Table 11-38).
11.4.5.4
MSCAN Normal Mode
This is a non-power-saving mode. Enabling the MSCAN puts the module from disabled mode into normal
mode. In this mode the module can either be in initialization mode or out of initialization mode. See
Section 11.4.4.5, “MSCAN Initialization Mode”.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
343
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.4.5.5
MSCAN Sleep Mode
The CPU can request the MSCAN to enter this low power mode by asserting the SLPRQ bit in the
CANCTL0 register. The time when the MSCAN enters sleep mode depends on a fixed synchronization
delay and its current activity:
• If there are one or more message buffers scheduled for transmission (TXEx = 0), the MSCAN will
continue to transmit until all transmit message buffers are empty (TXEx = 1, transmitted
successfully or aborted) and then goes into sleep mode.
• If the MSCAN is receiving, it continues to receive and goes into sleep mode as soon as the CAN
bus next becomes idle.
• If the MSCAN is neither transmitting nor receiving, it immediately goes into sleep mode.
Bus Clock Domain
CAN Clock Domain
SLPRQ
SYNC
sync.
SLPRQ
sync.
SYNC
SLPAK
CPU
Sleep Request
SLPAK
Flag
SLPAK
SLPRQ
Flag
MSCAN
in Sleep Mode
Figure 11-46. Sleep Request / Acknowledge Cycle
NOTE
The application software must avoid setting up a transmission (by clearing
one or more TXEx flag(s)) and immediately request sleep mode (by setting
SLPRQ). Whether the MSCAN starts transmitting or goes into sleep mode
directly depends on the exact sequence of operations.
If sleep mode is active, the SLPRQ and SLPAK bits are set (Figure 11-46). The application software must
use SLPAK as a handshake indication for the request (SLPRQ) to go into sleep mode.
When in sleep mode (SLPRQ = 1 and SLPAK = 1), the MSCAN stops its internal clocks. However, clocks
that allow register accesses from the CPU side continue to run.
If the MSCAN is in bus-off state, it stops counting the 128 occurrences of 11 consecutive recessive bits
due to the stopped clocks. TXCAN remains in a recessive state. If RXF = 1, the message can be read and
RXF can be cleared. Shifting a new message into the foreground buffer of the receiver FIFO (RxFG) does
not take place while in sleep mode.
It is possible to access the transmit buffers and to clear the associated TXE flags. No message abort takes
place while in sleep mode.
S12XS Family Reference Manual, Rev. 1.10
344
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
If the WUPE bit in CANCTL0 is not asserted, the MSCAN will mask any activity it detects on CAN.
RXCAN is therefore held internally in a recessive state. This locks the MSCAN in sleep mode. WUPE
must be set before entering sleep mode to take effect.
The MSCAN is able to leave sleep mode (wake up) only when:
• CAN bus activity occurs and WUPE = 1
or
• the CPU clears the SLPRQ bit
NOTE
The CPU cannot clear the SLPRQ bit before sleep mode (SLPRQ = 1 and
SLPAK = 1) is active.
After wake-up, the MSCAN waits for 11 consecutive recessive bits to synchronize to the CAN bus. As a
consequence, if the MSCAN is woken-up by a CAN frame, this frame is not received.
The receive message buffers (RxFG and RxBG) contain messages if they were received before sleep mode
was entered. All pending actions will be executed upon wake-up; copying of RxBG into RxFG, message
aborts and message transmissions. If the MSCAN remains in bus-off state after sleep mode was exited, it
continues counting the 128 occurrences of 11 consecutive recessive bits.
11.4.5.6
MSCAN Power Down Mode
The MSCAN is in power down mode (Table 11-38) when
• CPU is in stop mode
or
• CPU is in wait mode and the CSWAI bit is set
When entering the power down mode, the MSCAN immediately stops all ongoing transmissions and
receptions, potentially causing CAN protocol violations. To protect the CAN bus system from fatal
consequences of violations to the above rule, the MSCAN immediately drives TXCAN into a recessive
state.
NOTE
The user is responsible for ensuring that the MSCAN is not active when
power down mode is entered. The recommended procedure is to bring the
MSCAN into Sleep mode before the STOP or WAI instruction (if CSWAI
is set) is executed. Otherwise, the abort of an ongoing message can cause an
error condition and impact other CAN bus devices.
In power down mode, all clocks are stopped and no registers can be accessed. If the MSCAN was not in
sleep mode before power down mode became active, the module performs an internal recovery cycle after
powering up. This causes some fixed delay before the module enters normal mode again.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
345
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.4.5.7
Disabled Mode
The MSCAN is in disabled mode out of reset (CANE=0). All module clocks are stopped for power saving,
however the register map can still be accessed as specified.
11.4.5.8
Programmable Wake-Up Function
The MSCAN can be programmed to wake up from sleep or power down mode as soon as CAN bus activity
is detected (see control bit WUPE in MSCAN Control Register 0 (CANCTL0). The sensitivity to existing
CAN bus action can be modified by applying a low-pass filter function to the RXCAN input line (see
control bit WUPM in Section 11.3.2.2, “MSCAN Control Register 1 (CANCTL1)”).
This feature can be used to protect the MSCAN from wake-up due to short glitches on the CAN bus lines.
Such glitches can result from—for example—electromagnetic interference within noisy environments.
11.4.6
Reset Initialization
The reset state of each individual bit is listed in Section 11.3.2, “Register Descriptions,” which details all
the registers and their bit-fields.
11.4.7
Interrupts
This section describes all interrupts originated by the MSCAN. It documents the enable bits and generated
flags. Each interrupt is listed and described separately.
11.4.7.1
Description of Interrupt Operation
The MSCAN supports four interrupt vectors (see Table 11-39), any of which can be individually masked
(for details see Section 11.3.2.6, “MSCAN Receiver Interrupt Enable Register (CANRIER)” to
Section 11.3.2.8, “MSCAN Transmitter Interrupt Enable Register (CANTIER)”).
Refer to the device overview section to determine the dedicated interrupt vector addresses.
Table 11-39. Interrupt Vectors
Interrupt Source
Wake-Up Interrupt (WUPIF)
11.4.7.2
CCR Mask
I bit
Local Enable
CANRIER (WUPIE)
Error Interrupts Interrupt (CSCIF, OVRIF)
I bit
CANRIER (CSCIE, OVRIE)
Receive Interrupt (RXF)
I bit
CANRIER (RXFIE)
Transmit Interrupts (TXE[2:0])
I bit
CANTIER (TXEIE[2:0])
Transmit Interrupt
At least one of the three transmit buffers is empty (not scheduled) and can be loaded to schedule a message
for transmission. The TXEx flag of the empty message buffer is set.
S12XS Family Reference Manual, Rev. 1.10
346
Freescale Semiconductor
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.4.7.3
Receive Interrupt
A message is successfully received and shifted into the foreground buffer (RxFG) of the receiver FIFO.
This interrupt is generated immediately after receiving the EOF symbol. The RXF flag is set. If there are
multiple messages in the receiver FIFO, the RXF flag is set as soon as the next message is shifted to the
foreground buffer.
11.4.7.4
Wake-Up Interrupt
A wake-up interrupt is generated if activity on the CAN bus occurs during MSCAN sleep or power-down
mode.
NOTE
This interrupt can only occur if the MSCAN was in sleep mode (SLPRQ = 1
and SLPAK = 1) before entering power down mode, the wake-up option is
enabled (WUPE = 1), and the wake-up interrupt is enabled (WUPIE = 1).
11.4.7.5
Error Interrupt
An error interrupt is generated if an overrun of the receiver FIFO, error, warning, or bus-off condition
occurrs. MSCAN Receiver Flag Register (CANRFLG) indicates one of the following conditions:
• Overrun — An overrun condition of the receiver FIFO as described in Section 11.4.2.3, “Receive
Structures,” occurred.
• CAN Status Change — The actual value of the transmit and receive error counters control the
CAN bus state of the MSCAN. As soon as the error counters skip into a critical range (Tx/Rxwarning, Tx/Rx-error, bus-off) the MSCAN flags an error condition. The status change, which
caused the error condition, is indicated by the TSTAT and RSTAT flags (see Section 11.3.2.5,
“MSCAN Receiver Flag Register (CANRFLG)” and Section 11.3.2.6, “MSCAN Receiver
Interrupt Enable Register (CANRIER)”).
11.4.7.6
Interrupt Acknowledge
Interrupts are directly associated with one or more status flags in either the MSCAN Receiver Flag Register
(CANRFLG) or the MSCAN Transmitter Flag Register (CANTFLG). Interrupts are pending as long as
one of the corresponding flags is set. The flags in CANRFLG and CANTFLG must be reset within the
interrupt handler to handshake the interrupt. The flags are reset by writing a 1 to the corresponding bit
position. A flag cannot be cleared if the respective condition prevails.
NOTE
It must be guaranteed that the CPU clears only the bit causing the current
interrupt. For this reason, bit manipulation instructions (BSET) must not be
used to clear interrupt flags. These instructions may cause accidental
clearing of interrupt flags which are set after entering the current interrupt
service routine.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
347
Freescale’s Scalable Controller Area Network (S12MSCANV3)
11.5
11.5.1
Initialization/Application Information
MSCAN initialization
The procedure to initially start up the MSCAN module out of reset is as follows:
1. Assert CANE
2. Write to the configuration registers in initialization mode
3. Clear INITRQ to leave initialization mode
If the configuration of registers which are only writable in initialization mode shall be changed:
1. Bring the module into sleep mode by setting SLPRQ and awaiting SLPAK to assert after the CAN
bus becomes idle.
2. Enter initialization mode: assert INITRQ and await INITAK
3. Write to the configuration registers in initialization mode
4. Clear INITRQ to leave initialization mode and continue
11.5.2
Bus-Off Recovery
The bus-off recovery is user configurable. The bus-off state can either be left automatically or on user
request.
For reasons of backwards compatibility, the MSCAN defaults to automatic recovery after reset. In this
case, the MSCAN will become error active again after counting 128 occurrences of 11 consecutive
recessive bits on the CAN bus (see the Bosch CAN specification for details).
If the MSCAN is configured for user request (BORM set in MSCAN Control Register 1 (CANCTL1)), the
recovery from bus-off starts after both independent events have become true:
• 128 occurrences of 11 consecutive recessive bits on the CAN bus have been monitored
• BOHOLD in MSCAN Miscellaneous Register (CANMISC) has been cleared by the user
These two events may occur in any order.
S12XS Family Reference Manual, Rev. 1.10
348
Freescale Semiconductor
Chapter 12
Periodic Interrupt Timer (S12PIT24B4CV1)
Table 12-1. Revision History
Version
Number
12.1
Revision
Date
Effective
Date
Author
Description of Changes
01.00
28-Apr-05 28-Apr-05
Initial Release
01.01
05-Jul-05
Added application section, removed table 1-1
05-Jul-05
Introduction
The period interrupt timer (PIT) is an array of 24-bit timers that can be used to trigger peripheral modules
or raise periodic interrupts. Refer to Figure 12-1 for a simplified block diagram.
12.1.1
Glossary
Acronyms and Abbreviations
PIT
Periodic Interrupt Timer
ISR
Interrupt Service Routine
CCR
Condition Code Register
SoC
System on Chip
micro time bases
12.1.2
clock periods of the 16-bit timer modulus down-counters, which are generated by the 8-bit
modulus down-counters.
Features
The PIT includes these features:
• Four timers implemented as modulus down-counters with independent time-out periods.
• Time-out periods selectable between 1 and 224 bus clock cycles. Time-out equals m*n bus clock
cycles with 1 <= m <= 256 and 1 <= n <= 65536.
• Timers that can be enabled individually.
• Four time-out interrupts.
• Four time-out trigger output signals available to trigger peripheral modules.
• Start of timer channels can be aligned to each other.
12.1.3
Modes of Operation
Refer to the SoC guide for a detailed explanation of the chip modes.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
349
Periodic Interrupt Timer (S12PIT24B4CV1)
•
Run mode
This is the basic mode of operation.
Wait mode
PIT operation in wait mode is controlled by the PITSWAI bit located in the PITCFLMT register.
In wait mode, if the bus clock is globally enabled and if the PITSWAI bit is clear, the PIT operates
like in run mode. In wait mode, if the PITSWAI bit is set, the PIT module is stalled.
Stop mode
In full stop mode or pseudo stop mode, the PIT module is stalled.
Freeze mode
PIT operation in freeze mode is controlled by the PITFRZ bit located in the PITCFLMT register.
In freeze mode, if the PITFRZ bit is clear, the PIT operates like in run mode. In freeze mode, if the
PITFRZ bit is set, the PIT module is stalled.
•
•
•
12.1.4
Block Diagram
Figure 12-1 shows a block diagram of the PIT module.
Bus Clock
8-Bit
Micro Timer 0
Micro Time
Base 0
16-Bit Timer 0
16-Bit Timer 1
8-Bit
Micro Timer 1
Micro
Time
Base 1
16-Bit Timer 2
16-Bit Timer 3
Time-Out 0
Time-Out 1
Time-Out 2
Time-Out 3
Interrupt 0
Interface
Trigger 0
Interrupt 1
Interface
Trigger 1
Interrupt 2
Interface
Trigger 2
Interrupt 3
Interface
Trigger 3
Figure 12-1. PIT24B4C Block Diagram
12.2
External Signal Description
The PIT module has no external pins.
S12XS Family Reference Manual, Rev. 1.10
350
Freescale Semiconductor
Periodic Interrupt Timer (S12PIT24B4CV1)
12.3
Register Definition
This section consists of register descriptions in address order of the PIT. Each description includes a
standard register diagram with an associated figure number. Details of register bit and field function follow
the register diagrams, in bit order.
Register
Name
0x0000
PITCFLMT
R
W
0x0001
PITFLT
W
0x0002
PITCE
W
Bit 7
6
5
PITE
PITSWAI
PITFRZ
0
0
0
R
3
2
1
Bit 0
0
0
0
0
0
PFLMT1
PFLMT0
0
0
0
0
0
PFLT3
PFLT2
PFLT1
PFLT0
PCE3
PCE2
PCE1
PCE0
PMUX3
PMUX2
PMUX1
PMUX0
PINTE3
PINTE2
PINTE1
PINTE0
PTF3
PTF2
PTF1
PTF0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
PMTLD7
PMTLD6
PMTLD5
PMTLD4
PMTLD3
PMTLD2
PMTLD1
PMTLD0
PMTLD7
PMTLD6
PMTLD5
PMTLD4
PMTLD3
PMTLD2
PMTLD1
PMTLD0
PLD15
PLD14
PLD13
PLD12
PLD11
PLD10
PLD9
PLD8
PLD7
PLD6
PLD5
PLD4
PLD3
PLD2
PLD1
PLD0
0x000A
R
PITCNT0 (High) W
PCNT15
PCNT14
PCNT13
PCNT12
PCNT11
PCNT10
PCNT9
PCNT8
0x000B
R
PITCNT0 (Low) W
PCNT7
PCNT6
PCNT5
PCNT4
PCNT3
PCNT2
PCNT1
PCNT0
0x000C
PITLD1 (High)
PLD15
PLD14
PLD13
PLD12
PLD11
PLD10
PLD9
PLD8
0x0003
PITMUX
R
4
R
W
0x0004
PITINTE
W
0x0005
PITTF
W
0x0006
PITMTLD0
R
R
R
W
0x0007
PITMTLD1
W
0x0008
PITLD0 (High)
W
0x0009
PITLD0 (Low)
R
R
R
W
R
W
= Unimplemented or Reserved
Figure 12-2. PIT Register Summary (Sheet 1 of 2)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
351
Periodic Interrupt Timer (S12PIT24B4CV1)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
PLD7
PLD6
PLD5
PLD4
PLD3
PLD2
PLD1
PLD0
0x000E
R
PITCNT1 (High) W
PCNT15
PCNT14
PCNT13
PCNT12
PCNT11
PCNT10
PCNT9
PCNT8
0x000F
R
PITCNT1 (Low) W
PCNT7
PCNT6
PCNT5
PCNT4
PCNT3
PCNT2
PCNT1
PCNT0
0x0010
PITLD2 (High)
PLD15
PLD14
PLD13
PLD12
PLD11
PLD10
PLD9
PLD8
PLD7
PLD6
PLD5
PLD4
PLD3
PLD2
PLD1
PLD0
0x0012
R
PITCNT2 (High) W
PCNT15
PCNT14
PCNT13
PCNT12
PCNT11
PCNT10
PCNT9
PCNT8
0x0013
R
PITCNT2 (Low) W
PCNT7
PCNT6
PCNT5
PCNT4
PCNT3
PCNT2
PCNT1
PCNT0
PLD15
PLD14
PLD13
PLD12
PLD11
PLD10
PLD9
PLD8
PLD7
PLD6
PLD5
PLD4
PLD3
PLD2
PLD1
PLD0
0x0016
R
PITCNT3 (High) W
PCNT15
PCNT14
PCNT13
PCNT12
PCNT11
PCNT10
PCNT9
PCNT8
0x0017
R
PITCNT3 (Low) W
PCNT7
PCNT6
PCNT5
PCNT4
PCNT3
PCNT2
PCNT1
PCNT0
0
0
0
0
0
0
0
0
0x000D
PITLD1 (Low)
0x0011
PITLD2 (Low)
R
W
R
W
R
W
R
0x0014
PITLD3 (High)
W
0x0015
PITLD3 (Low)
W
R
0x0018−0x0027 R
RESERVED
W
= Unimplemented or Reserved
Figure 12-2. PIT Register Summary (Sheet 2 of 2)
S12XS Family Reference Manual, Rev. 1.10
352
Freescale Semiconductor
Periodic Interrupt Timer (S12PIT24B4CV1)
12.3.0.1
PIT Control and Force Load Micro Timer Register (PITCFLMT)
Module Base + 0x0000
R
W
Reset
7
6
5
PITE
PITSWAI
PITFRZ
0
0
0
4
3
2
0
0
0
0
0
0
1
0
0
0
PFLMT1
PFLMT0
0
0
= Unimplemented or Reserved
Figure 12-3. PIT Control and Force Load Micro Timer Register (PITCFLMT)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 12-2. PITCFLMT Field Descriptions
Field
Description
7
PITE
PIT Module Enable Bit — This bit enables the PIT module. If PITE is cleared, the PIT module is disabled and
flag bits in the PITTF register are cleared. When PITE is set, individually enabled timers (PCE set) start downcounting with the corresponding load register values.
0 PIT disabled (lower power consumption).
1 PIT is enabled.
6
PITSWAI
PIT Stop in Wait Mode Bit — This bit is used for power conservation while in wait mode.
0 PIT operates normally in wait mode
1 PIT clock generation stops and freezes the PIT module when in wait mode
5
PITFRZ
PIT Counter Freeze while in Freeze Mode Bit — When during debugging a breakpoint (freeze mode) is
encountered it is useful in many cases to freeze the PIT counters to avoid e.g. interrupt generation. The PITFRZ
bit controls the PIT operation while in freeze mode.
0 PIT operates normally in freeze mode
1 PIT counters are stalled when in freeze mode
1:0
PIT Force Load Bits for Micro Timer 1:0 — These bits have only an effect if the corresponding micro timer is
PFLMT[1:0] active and if the PIT module is enabled (PITE set). Writing a one into a PFLMT bit loads the corresponding 8-bit
micro timer load register into the 8-bit micro timer down-counter. Writing a zero has no effect. Reading these bits
will always return zero.
Note: A micro timer force load affects all timer channels that use the corresponding micro time base.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
353
Periodic Interrupt Timer (S12PIT24B4CV1)
12.3.0.2
PIT Force Load Timer Register (PITFLT)
Module Base + 0x0001
R
7
6
5
4
0
0
0
0
W
Reset
0
0
0
3
2
1
0
0
0
0
0
PFLT3
PFLT2
PFLT1
PFLT0
0
0
0
0
0
Figure 12-4. PIT Force Load Timer Register (PITFLT)
Read: Anytime
Write: Anytime
Table 12-3. PITFLT Field Descriptions
Field
Description
3:0
PFLT[3:0]
PIT Force Load Bits for Timer 3-0 — These bits have only an effect if the corresponding timer channel (PCE
set) is enabled and if the PIT module is enabled (PITE set). Writing a one into a PFLT bit loads the corresponding
16-bit timer load register into the 16-bit timer down-counter. Writing a zero has no effect. Reading these bits will
always return zero.
12.3.0.3
PIT Channel Enable Register (PITCE)
Module Base + 0x0002
R
7
6
5
4
0
0
0
0
0
0
0
0
W
Reset
3
2
1
0
PCE3
PCE2
PCE1
PCE0
0
0
0
0
Figure 12-5. PIT Channel Enable Register (PITCE)
Read: Anytime
Write: Anytime
Table 12-4. PITCE Field Descriptions
Field
Description
3:0
PCE[3:0]
PIT Enable Bits for Timer Channel 3:0 — These bits enable the PIT channels 3-0. If PCE is cleared, the PIT
channel is disabled and the corresponding flag bit in the PITTF register is cleared. When PCE is set, and if the
PIT module is enabled (PITE = 1) the 16-bit timer counter is loaded with the start count value and starts downcounting.
0 The corresponding PIT channel is disabled.
1 The corresponding PIT channel is enabled.
S12XS Family Reference Manual, Rev. 1.10
354
Freescale Semiconductor
Periodic Interrupt Timer (S12PIT24B4CV1)
12.3.0.4
PIT Multiplex Register (PITMUX)
Module Base + 0x0003
R
7
6
5
4
0
0
0
0
0
0
0
0
W
Reset
3
2
1
0
PMUX3
PMUX2
PMUX1
PMUX0
0
0
0
0
Figure 12-6. PIT Multiplex Register (PITMUX)
Read: Anytime
Write: Anytime
Table 12-5. PITMUX Field Descriptions
Field
Description
3:0
PMUX[3:0]
PIT Multiplex Bits for Timer Channel 3:0 — These bits select if the corresponding 16-bit timer is connected to
micro time base 1 or 0. If PMUX is modified, the corresponding 16-bit timer is switched to the other micro time
base immediately.
0 The corresponding 16-bit timer counts with micro time base 0.
1 The corresponding 16-bit timer counts with micro time base 1.
12.3.0.5
PIT Interrupt Enable Register (PITINTE)
Module Base + 0x0004
R
7
6
5
4
0
0
0
0
0
0
0
0
W
Reset
3
2
1
0
PINTE3
PINTE2
PINTE1
PINTE0
0
0
0
0
Figure 12-7. PIT Interrupt Enable Register (PITINTE)
Read: Anytime
Write: Anytime
Table 12-6. PITINTE Field Descriptions
Field
Description
3:0
PINTE[3:0]
PIT Time-out Interrupt Enable Bits for Timer Channel 3:0 — These bits enable an interrupt service request
whenever the time-out flag PTF of the corresponding PIT channel is set. When an interrupt is pending (PTF set)
enabling the interrupt will immediately cause an interrupt. To avoid this, the corresponding PTF flag has to be
cleared first.
0 Interrupt of the corresponding PIT channel is disabled.
1 Interrupt of the corresponding PIT channel is enabled.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
355
Periodic Interrupt Timer (S12PIT24B4CV1)
12.3.0.6
PIT Time-Out Flag Register (PITTF)
Module Base + 0x0005
R
7
6
5
4
0
0
0
0
0
0
0
0
W
Reset
3
2
1
0
PTF3
PTF2
PTF1
PTF0
0
0
0
0
Figure 12-8. PIT Time-Out Flag Register (PITTF)
Read: Anytime
Write: Anytime (write to clear)
Table 12-7. PITTF Field Descriptions
Field
Description
3:0
PTF[3:0]
PIT Time-out Flag Bits for Timer Channel 3:0 — PTF is set when the corresponding 16-bit timer modulus
down-counter and the selected 8-bit micro timer modulus down-counter have counted to zero. The flag can be
cleared by writing a one to the flag bit. Writing a zero has no effect. If flag clearing by writing a one and flag setting
happen in the same bus clock cycle, the flag remains set. The flag bits are cleared if the PIT module is disabled
or if the corresponding timer channel is disabled.
0 Time-out of the corresponding PIT channel has not yet occurred.
1 Time-out of the corresponding PIT channel has occurred.
12.3.0.7
PIT Micro Timer Load Register 0 to 1 (PITMTLD0–1)
Module Base + 0x0006
R
W
Reset
7
6
5
4
3
2
1
0
PMTLD7
PMTLD6
PMTLD5
PMTLD4
PMTLD3
PMTLD2
PMTLD1
PMTLD0
0
0
0
0
0
0
0
0
Figure 12-9. PIT Micro Timer Load Register 0 (PITMTLD0)
Module Base + 0x0007
R
W
Reset
7
6
5
4
3
2
1
0
PMTLD7
PMTLD6
PMTLD5
PMTLD4
PMTLD3
PMTLD2
PMTLD1
PMTLD0
0
0
0
0
0
0
0
0
Figure 12-10. PIT Micro Timer Load Register 1 (PITMTLD1)
Read: Anytime
Write: Anytime
S12XS Family Reference Manual, Rev. 1.10
356
Freescale Semiconductor
Periodic Interrupt Timer (S12PIT24B4CV1)
Table 12-8. PITMTLD0–1 Field Descriptions
Field
Description
7:0
PIT Micro Timer Load Bits 7:0 — These bits set the 8-bit modulus down-counter load value of the micro timers.
PMTLD[7:0] Writing a new value into the PITMTLD register will not restart the timer. When the micro timer has counted down
to zero, the PMTLD register value will be loaded. The PFLMT bits in the PITCFLMT register can be used to
immediately update the count register with the new value if an immediate load is desired.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
357
Periodic Interrupt Timer (S12PIT24B4CV1)
12.3.0.8
PIT Load Register 0 to 3 (PITLD0–3)
Module Base + 0x0008, 0x0009
15
R
W
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PLD15 PLD14 PLD13 PLD12 PLD11 PLD10 PLD9 PLD8 PLD7 PLD6 PLD5 PLD4 PLD3 PLD2 PLD1 PLD0
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4
3
2
1
0
Figure 12-11. PIT Load Register 0 (PITLD0)
Module Base + 0x000C, 0x000D
15
R
W
14
13
12
11
10
9
8
7
6
5
PLD15 PLD14 PLD13 PLD12 PLD11 PLD10 PLD9 PLD8 PLD7 PLD6 PLD5 PLD4 PLD3 PLD2 PLD1 PLD0
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4
3
2
1
0
Figure 12-12. PIT Load Register 1 (PITLD1)
Module Base + 0x0010, 0x0011
15
R
W
14
13
12
11
10
9
8
7
6
5
PLD15 PLD14 PLD13 PLD12 PLD11 PLD10 PLD9 PLD8 PLD7 PLD6 PLD5 PLD4 PLD3 PLD2 PLD1 PLD0
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4
3
2
1
0
Figure 12-13. PIT Load Register 2 (PITLD2)
Module Base + 0x0014, 0x0015
15
R
W
14
13
12
11
10
9
8
7
6
5
PLD15 PLD14 PLD13 PLD12 PLD11 PLD10 PLD9 PLD8 PLD7 PLD6 PLD5 PLD4 PLD3 PLD2 PLD1 PLD0
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 12-14. PIT Load Register 3 (PITLD3)
Read: Anytime
Write: Anytime
Table 12-9. PITLD0–3 Field Descriptions
Field
Description
15:0
PLD[15:0]
PIT Load Bits 15:0 — These bits set the 16-bit modulus down-counter load value. Writing a new value into the
PITLD register must be a 16-bit access, to ensure data consistency. It will not restart the timer. When the timer
has counted down to zero the PTF time-out flag will be set and the register value will be loaded. The PFLT bits
in the PITFLT register can be used to immediately update the count register with the new value if an immediate
load is desired.
S12XS Family Reference Manual, Rev. 1.10
358
Freescale Semiconductor
Periodic Interrupt Timer (S12PIT24B4CV1)
12.3.0.9
PIT Count Register 0 to 3 (PITCNT0–3)
Module Base + 0x000A, 0x000B
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4
3
2
1
0
Figure 12-15. PIT Count Register 0 (PITCNT0)
Module Base + 0x000E, 0x000F
15
14
13
12
11
10
9
8
7
6
5
R PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
W 15
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4
3
2
1
0
Figure 12-16. PIT Count Register 1 (PITCNT1)
Module Base + 0x0012, 0x0013
15
14
13
12
11
10
9
8
7
6
5
R PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
W 15
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4
3
2
1
0
Figure 12-17. PIT Count Register 2 (PITCNT2)
Module Base + 0x0016, 0x0017
15
14
13
12
11
10
9
8
7
6
5
R PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT PCNT
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
W 15
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 12-18. PIT Count Register 3 (PITCNT3)
Read: Anytime
Write: Has no meaning or effect
Table 12-10. PITCNT0–3 Field Descriptions
Field
Description
15:0
PIT Count Bits 15-0 — These bits represent the current 16-bit modulus down-counter value. The read access
PCNT[15:0] for the count register must take place in one clock cycle as a 16-bit access.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
359
Periodic Interrupt Timer (S12PIT24B4CV1)
12.4
Functional Description
Figure 12-19 shows a detailed block diagram of the PIT module. The main parts of the PIT are status,
control and data registers, two 8-bit down-counters, four 16-bit down-counters and an interrupt/trigger
interface.
4
PITFLT Register
PIT24B4C
PFLT0
PMUX0
4
PITMUX Register
Timer 0
PITLD0 Register
PITCNT0 Register
time-out 0
PFLT1
PITMLD0 Register
Bus
8-Bit Micro Timer 0
[0]
Timer 1
PITLD1 Register
PITCNT1 Register
PMUX
Clock
[1]
PITMLD1 Register
PFLT2
[2]
8-Bit Micro Timer 1
PITCFLMT Register
Timer 2
PITLD2 Register
PITCNT2 Register
[1]
PFLMT
time-out 1
timeout 3
PFLT3
[3]
Timer 3
PITLD3 Register
PITCNT3 Register
Interrupt /
Trigger Interface
4
Hardware
Trigger
PITTF Register
timeout 3
4
PITINTE Register
Interrupt
Request
Figure 12-19. PIT24B4C Detailed Block Diagram
12.4.1
Timer
As shown in Figure 12-1 and Figure 12-19, the 24-bit timers are built in a two-stage architecture with four
16-bit modulus down-counters and two 8-bit modulus down-counters. The 16-bit timers are clocked with
two selectable micro time bases which are generated with 8-bit modulus down-counters. Each 16-bit timer
is connected to micro time base 0 or 1 via the PMUX[3:0] bit setting in the PIT Multiplex (PITMUX)
register.
A timer channel is enabled if the module enable bit PITE in the PIT control and force load micro timer
(PITCFLMT) register is set and if the corresponding PCE bit in the PIT channel enable (PITCE) register
is set. Two 8-bit modulus down-counters are used to generate two micro time bases. As soon as a micro
time base is selected for an enabled timer channel, the corresponding micro timer modulus down-counter
will load its start value as specified in the PITMTLD0 or PITMTLD1 register and will start down-counting.
Whenever the micro timer down-counter has counted to zero the PITMTLD register is reloaded and the
connected 16-bit modulus down-counters count one cycle.
S12XS Family Reference Manual, Rev. 1.10
360
Freescale Semiconductor
Periodic Interrupt Timer (S12PIT24B4CV1)
Whenever a 16-bit timer counter and the connected 8-bit micro timer counter have counted to zero, the
PITLD register is reloaded and the corresponding time-out flag PTF in the PIT time-out flag (PITTF)
register is set, as shown in Figure 12-20. The time-out period is a function of the timer load (PITLD) and
micro timer load (PITMTLD) registers and the bus clock fBUS:
time-out period = (PITMTLD + 1) * (PITLD + 1) / fBUS.
For example, for a 40 MHz bus clock, the maximum time-out period equals:
256 * 65536 * 25 ns = 419.43 ms.
The current 16-bit modulus down-counter value can be read via the PITCNT register. The micro timer
down-counter values cannot be read.
The 8-bit micro timers can individually be restarted by writing a one to the corresponding force load micro
timer PFLMT bits in the PIT control and force load micro timer (PITCFLMT) register. The 16-bit timers
can individually be restarted by writing a one to the corresponding force load timer PFLT bits in the PIT
forceload timer (PITFLT) register. If desired, any group of timers and micro timers can be restarted at the
same time by using one 16-bit write to the adjacent PITCFLMT and PITFLT registers with the relevant
bits set, as shown in Figure 12-20.
Bus Clock
8-Bit Micro
0
Timer Counter
PITCNT Register
00
2
1
0
2
0001
1
0
2
0000
1
0001
0
2
1
0000
2
1
0
0001
2
1
0000
0
2
1
0
2
0001
8-Bit Force Load
16-Bit Force Load
PTF Flag1
PITTRIG
Time-Out Period
Note 1. The PTF flag clearing depends on the software
Time-Out Period
After Restart
Figure 12-20. PIT Trigger and Flag Signal Timing
12.4.2
Interrupt Interface
Each time-out event can be used to trigger an interrupt service request. For each timer channel, an
individual bit PINTE in the PIT interrupt enable (PITINTE) register exists to enable this feature. If PINTE
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
361
Periodic Interrupt Timer (S12PIT24B4CV1)
is set, an interrupt service is requested whenever the corresponding time-out flag PTF in the PIT time-out
flag (PITTF) register is set. The flag can be cleared by writing a one to the flag bit.
NOTE
Be careful when resetting the PITE, PINTE or PITCE bits in case of pending
PIT interrupt requests, to avoid spurious interrupt requests.
12.4.3
Hardware Trigger
The PIT module contains four hardware trigger signal lines PITTRIG[3:0], one for each timer channel.
These signals can be connected on SoC level to peripheral modules enabling e.g. periodic ATD conversion
(please refer to the SoC Guide for the mapping of PITTRIG[3:0] signals to peripheral modules).
Whenever a timer channel time-out is reached, the corresponding PTF flag is set and the corresponding
trigger signal PITTRIG triggers a rising edge. The trigger feature requires a minimum time-out period of
two bus clock cycles because the trigger is asserted high for at least one bus clock cycle. For load register
values PITLD = 0x0001 and PITMTLD = 0x0002 the flag setting, trigger timing and a restart with force
load is shown in Figure 12-20.
12.5
12.5.1
Initialization
Startup
Set the configuration registers before the PITE bit in the PITCFLMT register is set. Before PITE is set, the
configuration registers can be written in arbitrary order.
12.5.2
Shutdown
When the PITCE register bits, the PITINTE register bits or the PITE bit in the PITCFLMT register are
cleared, the corresponding PIT interrupt flags are cleared. In case of a pending PIT interrupt request, a
spurious interrupt can be generated. Two strategies, which avoid spurious interrupts, are recommended:
1. Reset the PIT interrupt flags only in an ISR. When entering the ISR, the I mask bit in the CCR is
set automatically. The I mask bit must not be cleared before the PIT interrupt flags are cleared.
2. After setting the I mask bit with the SEI instruction, the PIT interrupt flags can be cleared. Then
clear the I mask bit with the CLI instruction to re-enable interrupts.
12.5.3
Flag Clearing
A flag is cleared by writing a one to the flag bit. Always use store or move instructions to write a one in
certain bit positions. Do not use the BSET instructions. Do not use any C-constructs that compile to BSET
instructions. “BSET flag_register, #mask” must not be used for flag clearing because BSET is a readmodify-write instruction which writes back the “bit-wise or” of the flag_register and the mask into the
flag_register. BSET would clear all flag bits that were set, independent from the mask.
For example, to clear flag bit 0 use: MOVB #$01,PITTF.
S12XS Family Reference Manual, Rev. 1.10
362
Freescale Semiconductor
Periodic Interrupt Timer (S12PIT24B4CV1)
12.6
Application Information
To get started quickly with the PIT24B8C module this section provides a small code example how to use
the block. Please note that the example provided is only one specific case out of the possible configurations
and implementations.
Functionality: Generate an PIT interrupt on channel 0 every 500 PIT clock cycles.
ORG
LDS
MOVW
CODESTART
; place the program into specific
; range (to be selected)
RAMEND
; load stack pointer to top of RAM
#CH0_ISR,VEC_PIT_CH0 ; Change value of channel 0 ISR adr
; ******************** Start PIT Initialization *******************************************************
CLR
MOVB
CLR
MOVB
MOVW
MOVB
MOVB
CLI
PITCFLMT
#$01,PITCE
PITMUX
#$63,PITMTLD0
#$0004,PITLD0
#$01,PITINTE
#$80,PITCFLMT
; disable PIT
; enable timer channel 0
; ch0 connected to micro timer 0
; micro time base 0 equals 100 clock cycles
; time base 0 eq. 5 micro time bases 0 =5*100 = 500
; enable interupt channel 0
; enable PIT
; clear Interupt disable Mask bit
;******************** Main Program *************************************************************
MAIN:
BRA *
; loop until interrupt
;******************** Channel 0 Interupt Routine ***************************************************
CH0_ISR:
LDAA
MOVB
RTI
PITTF
#$01,PITTF
; 8 bit read of PIT time out flags
; clear PIT channel 0 time out flag
; return to MAIN
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
363
Periodic Interrupt Timer (S12PIT24B4CV1)
S12XS Family Reference Manual, Rev. 1.10
364
Freescale Semiconductor
Chapter 13
Pulse-Width Modulator (S12PWM8B8CV1)
Version Revision
Number
Date
01.17
13.1
Effective
Date
08-01-2004
Author
Description of Changes
Added clarification of PWMIF operation in STOP and WAIT mode.
Added notes on minimum pulse width of emergency shutdown
signal.
Introduction
The PWM definition is based on the HC12 PWM definitions. It contains the basic features from the HC11
with some of the enhancements incorporated on the HC12: center aligned output mode and four available
clock sources.The PWM module has eight channels with independent control of left and center aligned
outputs on each channel.
Each of the eight channels has a programmable period and duty cycle as well as a dedicated counter. A
flexible clock select scheme allows a total of four different clock sources to be used with the counters. Each
of the modulators can create independent continuous waveforms with software-selectable duty rates from
0% to 100%. The PWM outputs can be programmed as left aligned outputs or center aligned outputs.
13.1.1
Features
The PWM block includes these distinctive features:
• Eight independent PWM channels with programmable period and duty cycle
• Dedicated counter for each PWM channel
• Programmable PWM enable/disable for each channel
• Software selection of PWM duty pulse polarity for each channel
• Period and duty cycle are double buffered. Change takes effect when the end of the effective period
is reached (PWM counter reaches zero) or when the channel is disabled.
• Programmable center or left aligned outputs on individual channels
• Eight 8-bit channel or four 16-bit channel PWM resolution
• Four clock sources (A, B, SA, and SB) provide for a wide range of frequencies
• Programmable clock select logic
• Emergency shutdown
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
365
Pulse-Width Modulator (S12PWM8B8CV1)
13.1.2
Modes of Operation
There is a software programmable option for low power consumption in wait mode that disables the input
clock to the prescaler.
In freeze mode there is a software programmable option to disable the input clock to the prescaler. This is
useful for emulation.
13.1.3
Block Diagram
Figure 13-1 shows the block diagram for the 8-bit 8-channel PWM block.
PWM8B8C
PWM Channels
Channel 7
Period and Duty
Counter
Channel 6
Bus Clock
Clock Select
PWM Clock
Period and Duty
PWM6
Counter
Channel 5
Period and Duty
PWM7
PWM5
Counter
Control
Channel 4
Period and Duty
PWM4
Counter
Channel 3
Enable
Polarity
Period and Duty
Channel 2
Period and Duty
Alignment
PWM3
Counter
PWM2
Counter
Channel 1
Period and Duty
PWM1
Counter
Channel 0
Period and Duty
Counter
PWM0
Figure 13-1. PWM Block Diagram
13.2
External Signal Description
The PWM module has a total of 8 external pins.
S12XS Family Reference Manual, Rev. 1.10
366
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
13.2.1
PWM7 — PWM Channel 7
This pin serves as waveform output of PWM channel 7 and as an input for the emergency shutdown
feature.
13.2.2
PWM6 — PWM Channel 6
This pin serves as waveform output of PWM channel 6.
13.2.3
PWM5 — PWM Channel 5
This pin serves as waveform output of PWM channel 5.
13.2.4
PWM4 — PWM Channel 4
This pin serves as waveform output of PWM channel 4.
13.2.5
PWM3 — PWM Channel 3
This pin serves as waveform output of PWM channel 3.
13.2.6
PWM3 — PWM Channel 2
This pin serves as waveform output of PWM channel 2.
13.2.7
PWM3 — PWM Channel 1
This pin serves as waveform output of PWM channel 1.
13.2.8
PWM3 — PWM Channel 0
This pin serves as waveform output of PWM channel 0.
13.3
Memory Map and Register Definition
This section describes in detail all the registers and register bits in the PWM module.
The special-purpose registers and register bit functions that are not normally available to device end users,
such as factory test control registers and reserved registers, are clearly identified by means of shading the
appropriate portions of address maps and register diagrams. Notes explaining the reasons for restricting
access to the registers and functions are also explained in the individual register descriptions.
13.3.1
Module Memory Map
This section describes the content of the registers in the PWM module. The base address of the PWM
module is determined at the MCU level when the MCU is defined. The register decode map is fixed and
begins at the first address of the module address offset. The figure below shows the registers associated
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
367
Pulse-Width Modulator (S12PWM8B8CV1)
with the PWM and their relative offset from the base address. The register detail description follows the
order they appear in the register map.
Reserved bits within a register will always read as 0 and the write will be unimplemented. Unimplemented
functions are indicated by shading the bit. .
NOTE
Register Address = Base Address + Address Offset, where the Base Address
is defined at the MCU level and the Address Offset is defined at the module
level.
13.3.2
Register Descriptions
This section describes in detail all the registers and register bits in the PWM module.
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
PWME7
PWME6
PWME5
PWME4
PWME3
PWME2
PWME1
PWME0
PPOL7
PPOL6
PPOL5
PPOL4
PPOL3
PPOL2
PPOL1
PPOL0
PCLK7
PCLKL6
PCLK5
PCLK4
PCLK3
PCLK2
PCLK1
PCLK0
PCKB2
PCKB1
PCKB0
PCKA2
PCKA1
PCKA0
CAE7
CAE6
CAE5
CAE4
CAE3
CAE2
CAE1
CAE0
CON67
CON45
CON23
CON01
PSWAI
PFRZ
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0x0008
R
PWMSCLA W
Bit 7
6
5
4
3
2
1
Bit 0
0x0009
R
PWMSCLB W
Bit 7
6
5
4
3
2
1
Bit 0
0x0000
PWME
0x0001
PWMPOL
0x0002
PWMCLK
R
W
R
W
R
W
0x0003
R
PWMPRCLK W
0x0004
PWMCAE
R
W
0x0005
PWMCTL
R
W
0x0006
PWMTST1
W
R
0x0007
R
PWMPRSC1 W
0
0
= Unimplemented or Reserved
Figure 13-2. PWM Register Summary (Sheet 1 of 3)
S12XS Family Reference Manual, Rev. 1.10
368
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
0x000A
R
PWMSCNTA W
1
0
0
0
0
0
0
0
0
0x000B
R
PWMSCNTB W
1
0
0
0
0
0
0
0
0
0x000C
R
PWMCNT0 W
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0x000D
R
PWMCNT1 W
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0x000E
R
PWMCNT2 W
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
R
0x000F
PWMCNT3 W
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0x0010
R
PWMCNT4 W
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0x0011
R
PWMCNT5 W
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0x0012
R
PWMCNT6 W
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0x0013
R
PWMCNT7 W
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0x0014
R
PWMPER0 W
Bit 7
6
5
4
3
2
1
Bit 0
0x0015
R
PWMPER1 W
Bit 7
6
5
4
3
2
1
Bit 0
0x0016
R
PWMPER2 W
Bit 7
6
5
4
3
2
1
Bit 0
0x0017
R
PWMPER3 W
Bit 7
6
5
4
3
2
1
Bit 0
0x0018
R
PWMPER4 W
Bit 7
6
5
4
3
2
1
Bit 0
= Unimplemented or Reserved
Figure 13-2. PWM Register Summary (Sheet 2 of 3)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
369
Pulse-Width Modulator (S12PWM8B8CV1)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
0x0019
R
PWMPER5 W
Bit 7
6
5
4
3
2
1
Bit 0
0x001A
R
PWMPER6 W
Bit 7
6
5
4
3
2
1
Bit 0
0x001B
R
PWMPER7 W
Bit 7
6
5
4
3
2
1
Bit 0
0x001C
R
PWMDTY0 W
Bit 7
6
5
4
3
2
1
Bit 0
0x001D
R
PWMDTY1 W
Bit 7
6
5
4
3
2
1
Bit 0
0x001E
R
PWMDTY2 W
Bit 7
6
5
4
3
2
1
Bit 0
0x001F
R
PWMDTY3 W
Bit 7
6
5
4
3
2
1
Bit 0
0x0010
R
PWMDTY4 W
Bit 7
6
5
4
3
2
1
Bit 0
0x0021
R
PWMDTY5 W
Bit 7
6
5
4
3
2
1
Bit 0
0x0022
R
PWMDTY6 W
Bit 7
6
5
4
3
2
1
Bit 0
0x0023
R
PWMDTY7 W
Bit 7
6
5
4
3
2
1
Bit 0
PWMIF
PWMIE
0
PWM7IN
PWM7INL
PWM7ENA
0x0024
PWMSDN
R
W
0
PWMRSTRT
PWMLVL
= Unimplemented or Reserved
Figure 13-2. PWM Register Summary (Sheet 3 of 3)
1
Intended for factory test purposes only.
13.3.2.1
PWM Enable Register (PWME)
Each PWM channel has an enable bit (PWMEx) to start its waveform output. When any of the PWMEx
bits are set (PWMEx = 1), the associated PWM output is enabled immediately. However, the actual PWM
waveform is not available on the associated PWM output until its clock source begins its next cycle due to
the synchronization of PWMEx and the clock source.
S12XS Family Reference Manual, Rev. 1.10
370
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
NOTE
The first PWM cycle after enabling the channel can be irregular.
An exception to this is when channels are concatenated. Once concatenated mode is enabled (CONxx bits
set in PWMCTL register), enabling/disabling the corresponding 16-bit PWM channel is controlled by the
low order PWMEx bit.In this case, the high order bytes PWMEx bits have no effect and their
corresponding PWM output lines are disabled.
While in run mode, if all eight PWM channels are disabled (PWME7–0 = 0), the prescaler counter shuts
off for power savings.
Module Base + 0x0000
R
W
Reset
7
6
5
4
3
2
1
0
PWME7
PWME6
PWME5
PWME4
PWME3
PWME2
PWME1
PWME0
0
0
0
0
0
0
0
0
Figure 13-3. PWM Enable Register (PWME)
Read: Anytime
Write: Anytime
Table 13-1. PWME Field Descriptions
Field
Description
7
PWME7
Pulse Width Channel 7 Enable
0 Pulse width channel 7 is disabled.
1 Pulse width channel 7 is enabled. The pulse modulated signal becomes available at PWM output bit 7 when
its clock source begins its next cycle.
6
PWME6
Pulse Width Channel 6 Enable
0 Pulse width channel 6 is disabled.
1 Pulse width channel 6 is enabled. The pulse modulated signal becomes available at PWM output bit6 when
its clock source begins its next cycle. If CON67=1, then bit has no effect and PWM output line 6 is disabled.
5
PWME5
Pulse Width Channel 5 Enable
0 Pulse width channel 5 is disabled.
1 Pulse width channel 5 is enabled. The pulse modulated signal becomes available at PWM output bit 5 when
its clock source begins its next cycle.
4
PWME4
Pulse Width Channel 4 Enable
0 Pulse width channel 4 is disabled.
1 Pulse width channel 4 is enabled. The pulse modulated signal becomes available at PWM, output bit 4 when
its clock source begins its next cycle. If CON45 = 1, then bit has no effect and PWM output bit4 is disabled.
3
PWME3
Pulse Width Channel 3 Enable
0 Pulse width channel 3 is disabled.
1 Pulse width channel 3 is enabled. The pulse modulated signal becomes available at PWM, output bit 3 when
its clock source begins its next cycle.
2
PWME2
Pulse Width Channel 2 Enable
0 Pulse width channel 2 is disabled.
1 Pulse width channel 2 is enabled. The pulse modulated signal becomes available at PWM, output bit 2 when
its clock source begins its next cycle. If CON23 = 1, then bit has no effect and PWM output bit2 is disabled.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
371
Pulse-Width Modulator (S12PWM8B8CV1)
Table 13-1. PWME Field Descriptions (continued)
Field
Description
1
PWME1
Pulse Width Channel 1 Enable
0 Pulse width channel 1 is disabled.
1 Pulse width channel 1 is enabled. The pulse modulated signal becomes available at PWM, output bit 1 when
its clock source begins its next cycle.
0
PWME0
Pulse Width Channel 0 Enable
0 Pulse width channel 0 is disabled.
1 Pulse width channel 0 is enabled. The pulse modulated signal becomes available at PWM, output bit 0 when
its clock source begins its next cycle. If CON01 = 1, then bit has no effect and PWM output line0 is disabled.
13.3.2.2
PWM Polarity Register (PWMPOL)
The starting polarity of each PWM channel waveform is determined by the associated PPOLx bit in the
PWMPOL register. If the polarity bit is one, the PWM channel output is high at the beginning of the cycle
and then goes low when the duty count is reached. Conversely, if the polarity bit is zero, the output starts
low and then goes high when the duty count is reached.
Module Base + 0x0001
R
W
Reset
7
6
5
4
3
2
1
0
PPOL7
PPOL6
PPOL5
PPOL4
PPOL3
PPOL2
PPOL1
PPOL0
0
0
0
0
0
0
0
0
Figure 13-4. PWM Polarity Register (PWMPOL)
Read: Anytime
Write: Anytime
NOTE
PPOLx register bits can be written anytime. If the polarity is changed while
a PWM signal is being generated, a truncated or stretched pulse can occur
during the transition
Table 13-2. PWMPOL Field Descriptions
Field
7–0
PPOL[7:0]
13.3.2.3
Description
Pulse Width Channel 7–0 Polarity Bits
0 PWM channel 7–0 outputs are low at the beginning of the period, then go high when the duty count is
reached.
1 PWM channel 7–0 outputs are high at the beginning of the period, then go low when the duty count is
reached.
PWM Clock Select Register (PWMCLK)
Each PWM channel has a choice of two clocks to use as the clock source for that channel as described
below.
S12XS Family Reference Manual, Rev. 1.10
372
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
Module Base + 0x0002
R
W
Reset
7
6
5
4
3
2
1
0
PCLK7
PCLKL6
PCLK5
PCLK4
PCLK3
PCLK2
PCLK1
PCLK0
0
0
0
0
0
0
0
0
Figure 13-5. PWM Clock Select Register (PWMCLK)
Read: Anytime
Write: Anytime
NOTE
Register bits PCLK0 to PCLK7 can be written anytime. If a clock select is
changed while a PWM signal is being generated, a truncated or stretched
pulse can occur during the transition.
Table 13-3. PWMCLK Field Descriptions
Field
Description
7
PCLK7
Pulse Width Channel 7 Clock Select
0 Clock B is the clock source for PWM channel 7.
1 Clock SB is the clock source for PWM channel 7.
6
PCLK6
Pulse Width Channel 6 Clock Select
0 Clock B is the clock source for PWM channel 6.
1 Clock SB is the clock source for PWM channel 6.
5
PCLK5
Pulse Width Channel 5 Clock Select
0 Clock A is the clock source for PWM channel 5.
1 Clock SA is the clock source for PWM channel 5.
4
PCLK4
Pulse Width Channel 4 Clock Select
0 Clock A is the clock source for PWM channel 4.
1 Clock SA is the clock source for PWM channel 4.
3
PCLK3
Pulse Width Channel 3 Clock Select
0 Clock B is the clock source for PWM channel 3.
1 Clock SB is the clock source for PWM channel 3.
2
PCLK2
Pulse Width Channel 2 Clock Select
0 Clock B is the clock source for PWM channel 2.
1 Clock SB is the clock source for PWM channel 2.
1
PCLK1
Pulse Width Channel 1 Clock Select
0 Clock A is the clock source for PWM channel 1.
1 Clock SA is the clock source for PWM channel 1.
0
PCLK0
Pulse Width Channel 0 Clock Select
0 Clock A is the clock source for PWM channel 0.
1 Clock SA is the clock source for PWM channel 0.
13.3.2.4
PWM Prescale Clock Select Register (PWMPRCLK)
This register selects the prescale clock source for clocks A and B independently.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
373
Pulse-Width Modulator (S12PWM8B8CV1)
Module Base + 0x0003
7
R
6
0
W
Reset
0
5
4
3
PCKB2
PCKB1
PCKB0
0
0
0
0
2
1
0
PCKA2
PCKA1
PCKA0
0
0
0
0
= Unimplemented or Reserved
Figure 13-6. PWM Prescale Clock Select Register (PWMPRCLK)
Read: Anytime
Write: Anytime
NOTE
PCKB2–0 and PCKA2–0 register bits can be written anytime. If the clock
pre-scale is changed while a PWM signal is being generated, a truncated or
stretched pulse can occur during the transition.
Table 13-4. PWMPRCLK Field Descriptions
Field
Description
6–4
PCKB[2:0]
Prescaler Select for Clock B — Clock B is one of two clock sources which can be used for channels 2, 3, 6, or
7. These three bits determine the rate of clock B, as shown in Table 13-5.
2–0
PCKA[2:0]
Prescaler Select for Clock A — Clock A is one of two clock sources which can be used for channels 0, 1, 4 or
5. These three bits determine the rate of clock A, as shown in Table 13-6.
s
Table 13-5. Clock B Prescaler Selects
PCKB2
PCKB1
PCKB0
Value of Clock B
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Bus clock
Bus clock / 2
Bus clock / 4
Bus clock / 8
Bus clock / 16
Bus clock / 32
Bus clock / 64
Bus clock / 128
Table 13-6. Clock A Prescaler Selects
PCKA2
PCKA1
PCKA0
Value of Clock A
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Bus clock
Bus clock / 2
Bus clock / 4
Bus clock / 8
Bus clock / 16
Bus clock / 32
Bus clock / 64
Bus clock / 128
S12XS Family Reference Manual, Rev. 1.10
374
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
13.3.2.5
PWM Center Align Enable Register (PWMCAE)
The PWMCAE register contains eight control bits for the selection of center aligned outputs or left aligned
outputs for each PWM channel. If the CAEx bit is set to a one, the corresponding PWM output will be
center aligned. If the CAEx bit is cleared, the corresponding PWM output will be left aligned. See
Section 13.4.2.5, “Left Aligned Outputs” and Section 13.4.2.6, “Center Aligned Outputs” for a more
detailed description of the PWM output modes.
Module Base + 0x0004
R
W
Reset
7
6
5
4
3
2
1
0
CAE7
CAE6
CAE5
CAE4
CAE3
CAE2
CAE1
CAE0
0
0
0
0
0
0
0
0
Figure 13-7. PWM Center Align Enable Register (PWMCAE)
Read: Anytime
Write: Anytime
NOTE
Write these bits only when the corresponding channel is disabled.
Table 13-7. PWMCAE Field Descriptions
Field
7–0
CAE[7:0]
13.3.2.6
Description
Center Aligned Output Modes on Channels 7–0
0 Channels 7–0 operate in left aligned output mode.
1 Channels 7–0 operate in center aligned output mode.
PWM Control Register (PWMCTL)
The PWMCTL register provides for various control of the PWM module.
Module Base + 0x0005
7
R
W
Reset
6
5
4
3
2
CON67
CON45
CON23
CON01
PSWAI
PFRZ
0
0
0
0
0
0
1
0
0
0
0
0
= Unimplemented or Reserved
Figure 13-8. PWM Control Register (PWMCTL)
Read: Anytime
Write: Anytime
There are three control bits for concatenation, each of which is used to concatenate a pair of PWM
channels into one 16-bit channel. When channels 6 and 7are concatenated, channel 6 registers become the
high order bytes of the double byte channel. When channels 4 and 5 are concatenated, channel 4 registers
become the high order bytes of the double byte channel. When channels 2 and 3 are concatenated, channel
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
375
Pulse-Width Modulator (S12PWM8B8CV1)
2 registers become the high order bytes of the double byte channel. When channels 0 and 1 are
concatenated, channel 0 registers become the high order bytes of the double byte channel.
See Section 13.4.2.7, “PWM 16-Bit Functions” for a more detailed description of the concatenation PWM
Function.
NOTE
Change these bits only when both corresponding channels are disabled.
Table 13-8. PWMCTL Field Descriptions
Field
Description
7
CON67
Concatenate Channels 6 and 7
0 Channels 6 and 7 are separate 8-bit PWMs.
1 Channels 6 and 7 are concatenated to create one 16-bit PWM channel. Channel 6 becomes the high order
byte and channel 7 becomes the low order byte. Channel 7 output pin is used as the output for this 16-bit
PWM (bit 7 of port PWMP). Channel 7 clock select control-bit determines the clock source, channel 7 polarity
bit determines the polarity, channel 7 enable bit enables the output and channel 7 center aligned enable bit
determines the output mode.
6
CON45
Concatenate Channels 4 and 5
0 Channels 4 and 5 are separate 8-bit PWMs.
1 Channels 4 and 5 are concatenated to create one 16-bit PWM channel. Channel 4 becomes the high order
byte and channel 5 becomes the low order byte. Channel 5 output pin is used as the output for this 16-bit
PWM (bit 5 of port PWMP). Channel 5 clock select control-bit determines the clock source, channel 5 polarity
bit determines the polarity, channel 5 enable bit enables the output and channel 5 center aligned enable bit
determines the output mode.
5
CON23
Concatenate Channels 2 and 3
0 Channels 2 and 3 are separate 8-bit PWMs.
1 Channels 2 and 3 are concatenated to create one 16-bit PWM channel. Channel 2 becomes the high order
byte and channel 3 becomes the low order byte. Channel 3 output pin is used as the output for this 16-bit
PWM (bit 3 of port PWMP). Channel 3 clock select control-bit determines the clock source, channel 3 polarity
bit determines the polarity, channel 3 enable bit enables the output and channel 3 center aligned enable bit
determines the output mode.
4
CON01
Concatenate Channels 0 and 1
0 Channels 0 and 1 are separate 8-bit PWMs.
1 Channels 0 and 1 are concatenated to create one 16-bit PWM channel. Channel 0 becomes the high order
byte and channel 1 becomes the low order byte. Channel 1 output pin is used as the output for this 16-bit
PWM (bit 1 of port PWMP). Channel 1 clock select control-bit determines the clock source, channel 1 polarity
bit determines the polarity, channel 1 enable bit enables the output and channel 1 center aligned enable bit
determines the output mode.
3
PSWAI
PWM Stops in Wait Mode — Enabling this bit allows for lower power consumption in wait mode by disabling
the input clock to the prescaler.
0 Allow the clock to the prescaler to continue while in wait mode.
1 Stop the input clock to the prescaler whenever the MCU is in wait mode.
2
PFREZ
PWM Counters Stop in Freeze Mode — In freeze mode, there is an option to disable the input clock to the
prescaler by setting the PFRZ bit in the PWMCTL register. If this bit is set, whenever the MCU is in freeze mode,
the input clock to the prescaler is disabled. This feature is useful during emulation as it allows the PWM function
to be suspended. In this way, the counters of the PWM can be stopped while in freeze mode so that once normal
program flow is continued, the counters are re-enabled to simulate real-time operations. Since the registers can
still be accessed in this mode, to re-enable the prescaler clock, either disable the PFRZ bit or exit freeze mode.
0 Allow PWM to continue while in freeze mode.
1 Disable PWM input clock to the prescaler whenever the part is in freeze mode. This is useful for emulation.
S12XS Family Reference Manual, Rev. 1.10
376
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
13.3.2.7
Reserved Register (PWMTST)
This register is reserved for factory testing of the PWM module and is not available in normal modes.
Module Base + 0x0006
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 13-9. Reserved Register (PWMTST)
Read: Always read $00 in normal modes
Write: Unimplemented in normal modes
NOTE
Writing to this register when in special modes can alter the PWM
functionality.
13.3.2.8
Reserved Register (PWMPRSC)
This register is reserved for factory testing of the PWM module and is not available in normal modes.
Module Base + 0x0007
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 13-10. Reserved Register (PWMPRSC)
Read: Always read $00 in normal modes
Write: Unimplemented in normal modes
NOTE
Writing to this register when in special modes can alter the PWM
functionality.
13.3.2.9
PWM Scale A Register (PWMSCLA)
PWMSCLA is the programmable scale value used in scaling clock A to generate clock SA. Clock SA is
generated by taking clock A, dividing it by the value in the PWMSCLA register and dividing that by two.
Clock SA = Clock A / (2 * PWMSCLA)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
377
Pulse-Width Modulator (S12PWM8B8CV1)
NOTE
When PWMSCLA = $00, PWMSCLA value is considered a full scale value
of 256. Clock A is thus divided by 512.
Any value written to this register will cause the scale counter to load the new scale value (PWMSCLA).
Module Base + 0x0008
R
W
Reset
7
6
5
4
3
2
1
0
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
Figure 13-11. PWM Scale A Register (PWMSCLA)
Read: Anytime
Write: Anytime (causes the scale counter to load the PWMSCLA value)
13.3.2.10 PWM Scale B Register (PWMSCLB)
PWMSCLB is the programmable scale value used in scaling clock B to generate clock SB. Clock SB is
generated by taking clock B, dividing it by the value in the PWMSCLB register and dividing that by two.
Clock SB = Clock B / (2 * PWMSCLB)
NOTE
When PWMSCLB = $00, PWMSCLB value is considered a full scale value
of 256. Clock B is thus divided by 512.
Any value written to this register will cause the scale counter to load the new scale value (PWMSCLB).
Module Base + 0x0009
R
W
Reset
7
6
5
4
3
2
1
0
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
Figure 13-12. PWM Scale B Register (PWMSCLB)
Read: Anytime
Write: Anytime (causes the scale counter to load the PWMSCLB value).
13.3.2.11 Reserved Registers (PWMSCNTx)
The registers PWMSCNTA and PWMSCNTB are reserved for factory testing of the PWM module and are
not available in normal modes.
S12XS Family Reference Manual, Rev. 1.10
378
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
Module Base + 0x000A, 0x000B
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 13-13. Reserved Registers (PWMSCNTx)
Read: Always read $00 in normal modes
Write: Unimplemented in normal modes
NOTE
Writing to these registers when in special modes can alter the PWM
functionality.
13.3.2.12 PWM Channel Counter Registers (PWMCNTx)
Each channel has a dedicated 8-bit up/down counter which runs at the rate of the selected clock source.
The counter can be read at any time without affecting the count or the operation of the PWM channel. In
left aligned output mode, the counter counts from 0 to the value in the period register - 1. In center aligned
output mode, the counter counts from 0 up to the value in the period register and then back down to 0.
Any value written to the counter causes the counter to reset to $00, the counter direction to be set to up,
the immediate load of both duty and period registers with values from the buffers, and the output to change
according to the polarity bit. The counter is also cleared at the end of the effective period (see
Section 13.4.2.5, “Left Aligned Outputs” and Section 13.4.2.6, “Center Aligned Outputs” for more
details). When the channel is disabled (PWMEx = 0), the PWMCNTx register does not count. When a
channel becomes enabled (PWMEx = 1), the associated PWM counter starts at the count in the
PWMCNTx register. For more detailed information on the operation of the counters, see Section 13.4.2.4,
“PWM Timer Counters”.
In concatenated mode, writes to the 16-bit counter by using a 16-bit access or writes to either the low or
high order byte of the counter will reset the 16-bit counter. Reads of the 16-bit counter must be made by
16-bit access to maintain data coherency.
NOTE
Writing to the counter while the channel is enabled can cause an irregular PWM cycle to occur.
Module Base + 0x000C = PWMCNT0, 0x000D = PWMCNT1, 0x000E = PWMCNT2, 0x000F = PWMCNT3
Module Base + 0x0010 = PWMCNT4, 0x0011 = PWMCNT5, 0x0012 = PWMCNT6, 0x0013 = PWMCNT7
7
6
5
4
3
2
1
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
Reset
0
0
0
0
0
0
0
0
Figure 13-14. PWM Channel Counter Registers (PWMCNTx)
Read: Anytime
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
379
Pulse-Width Modulator (S12PWM8B8CV1)
Write: Anytime (any value written causes PWM counter to be reset to $00).
13.3.2.13 PWM Channel Period Registers (PWMPERx)
There is a dedicated period register for each channel. The value in this register determines the period of
the associated PWM channel.
The period registers for each channel are double buffered so that if they change while the channel is
enabled, the change will NOT take effect until one of the following occurs:
• The effective period ends
• The counter is written (counter resets to $00)
• The channel is disabled
In this way, the output of the PWM will always be either the old waveform or the new waveform, not some
variation in between. If the channel is not enabled, then writes to the period register will go directly to the
latches as well as the buffer.
NOTE
Reads of this register return the most recent value written. Reads do not
necessarily return the value of the currently active period due to the double
buffering scheme.
See Section 13.4.2.3, “PWM Period and Duty” for more information.
To calculate the output period, take the selected clock source period for the channel of interest (A, B, SA,
or SB) and multiply it by the value in the period register for that channel:
• Left aligned output (CAEx = 0)
• PWMx Period = Channel Clock Period * PWMPERx Center Aligned Output (CAEx = 1)
PWMx Period = Channel Clock Period * (2 * PWMPERx)
For boundary case programming values, please refer to Section 13.4.2.8, “PWM Boundary Cases”.
Module Base + 0x0014 = PWMPER0, 0x0015 = PWMPER1, 0x0016 = PWMPER2, 0x0017 = PWMPER3
Module Base + 0x0018 = PWMPER4, 0x0019 = PWMPER5, 0x001A = PWMPER6, 0x001B = PWMPER7
R
W
Reset
7
6
5
4
3
2
1
0
Bit 7
6
5
4
3
2
1
Bit 0
1
1
1
1
1
1
1
1
Figure 13-15. PWM Channel Period Registers (PWMPERx)
Read: Anytime
Write: Anytime
S12XS Family Reference Manual, Rev. 1.10
380
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
13.3.2.14 PWM Channel Duty Registers (PWMDTYx)
There is a dedicated duty register for each channel. The value in this register determines the duty of the
associated PWM channel. The duty value is compared to the counter and if it is equal to the counter value
a match occurs and the output changes state.
The duty registers for each channel are double buffered so that if they change while the channel is enabled,
the change will NOT take effect until one of the following occurs:
• The effective period ends
• The counter is written (counter resets to $00)
• The channel is disabled
In this way, the output of the PWM will always be either the old duty waveform or the new duty waveform,
not some variation in between. If the channel is not enabled, then writes to the duty register will go directly
to the latches as well as the buffer.
NOTE
Reads of this register return the most recent value written. Reads do not
necessarily return the value of the currently active duty due to the double
buffering scheme.
See Section 13.4.2.3, “PWM Period and Duty” for more information.
NOTE
Depending on the polarity bit, the duty registers will contain the count of
either the high time or the low time. If the polarity bit is one, the output starts
high and then goes low when the duty count is reached, so the duty registers
contain a count of the high time. If the polarity bit is zero, the output starts
low and then goes high when the duty count is reached, so the duty registers
contain a count of the low time.
To calculate the output duty cycle (high time as a% of period) for a particular channel:
•
•
Polarity = 0 (PPOL x =0)
Duty Cycle = [(PWMPERx-PWMDTYx)/PWMPERx] * 100%
Polarity = 1 (PPOLx = 1)
Duty Cycle = [PWMDTYx / PWMPERx] * 100%
For boundary case programming values, please refer to Section 13.4.2.8, “PWM Boundary Cases”.
Module Base + 0x001C = PWMDTY0, 0x001D = PWMDTY1, 0x001E = PWMDTY2, 0x001F = PWMDTY3
Module Base + 0x0020 = PWMDTY4, 0x0021 = PWMDTY5, 0x0022 = PWMDTY6, 0x0023 = PWMDTY7
R
W
Reset
7
6
5
4
3
2
1
0
Bit 7
6
5
4
3
2
1
Bit 0
1
1
1
1
1
1
1
1
Figure 13-16. PWM Channel Duty Registers (PWMDTYx)
Read: Anytime
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
381
Pulse-Width Modulator (S12PWM8B8CV1)
Write: Anytime
13.3.2.15 PWM Shutdown Register (PWMSDN)
The PWMSDN register provides for the shutdown functionality of the PWM module in the emergency
cases. For proper operation, channel 7 must be driven to the active level for a minimum of two bus clocks.
Module Base + 0x0024
7
R
W
Reset
PWMIF
0
6
5
PWMIE
0
0
PWMRSTRT
0
4
PWMLVL
0
3
2
0
PWM7IN
0
0
1
0
PWM7INL
PWM7ENA
0
0
= Unimplemented or Reserved
Figure 13-17. PWM Shutdown Register (PWMSDN)
Read: Anytime
Write: Anytime
Table 13-9. PWMSDN Field Descriptions
Field
Description
7
PWMIF
PWM Interrupt Flag — Any change from passive to asserted (active) state or from active to passive state will
be flagged by setting the PWMIF flag = 1. The flag is cleared by writing a logic 1 to it. Writing a 0 has no effect.
0 No change on PWM7IN input.
1 Change on PWM7IN input
6
PWMIE
PWM Interrupt Enable — If interrupt is enabled an interrupt to the CPU is asserted.
0 PWM interrupt is disabled.
1 PWM interrupt is enabled.
5
PWM Restart — The PWM can only be restarted if the PWM channel input 7 is de-asserted. After writing a logic
PWMRSTRT 1 to the PWMRSTRT bit (trigger event) the PWM channels start running after the corresponding counter passes
next “counter == 0” phase. Also, if the PWM7ENA bit is reset to 0, the PWM do not start before the counter
passes $00. The bit is always read as “0”.
4
PWMLVL
PWM Shutdown Output Level If active level as defined by the PWM7IN input, gets asserted all enabled PWM
channels are immediately driven to the level defined by PWMLVL.
0 PWM outputs are forced to 0
1 Outputs are forced to 1.
2
PWM7IN
PWM Channel 7 Input Status — This reflects the current status of the PWM7 pin.
1
PWM7INL
PWM Shutdown Active Input Level for Channel 7 — If the emergency shutdown feature is enabled
(PWM7ENA = 1), this bit determines the active level of the PWM7channel.
0 Active level is low
1 Active level is high
0
PWM7ENA
PWM Emergency Shutdown Enable — If this bit is logic 1, the pin associated with channel 7 is forced to input
and the emergency shutdown feature is enabled. All the other bits in this register are meaningful only if
PWM7ENA = 1.
0 PWM emergency feature disabled.
1 PWM emergency feature is enabled.
S12XS Family Reference Manual, Rev. 1.10
382
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
13.4
Functional Description
13.4.1
PWM Clock Select
There are four available clocks: clock A, clock B, clock SA (scaled A), and clock SB (scaled B). These
four clocks are based on the bus clock.
Clock A and B can be software selected to be 1, 1/2, 1/4, 1/8,..., 1/64, 1/128 times the bus clock. Clock SA
uses clock A as an input and divides it further with a reloadable counter. Similarly, clock SB uses clock B
as an input and divides it further with a reloadable counter. The rates available for clock SA are software
selectable to be clock A divided by 2, 4, 6, 8,..., or 512 in increments of divide by 2. Similar rates are
available for clock SB. Each PWM channel has the capability of selecting one of two clocks, either the
pre-scaled clock (clock A or B) or the scaled clock (clock SA or SB).
The block diagram in Figure 13-18 shows the four different clocks and how the scaled clocks are created.
13.4.1.1
Prescale
The input clock to the PWM prescaler is the bus clock. It can be disabled whenever the part is in freeze
mode by setting the PFRZ bit in the PWMCTL register. If this bit is set, whenever the MCU is in freeze
mode (freeze mode signal active) the input clock to the prescaler is disabled. This is useful for emulation
in order to freeze the PWM. The input clock can also be disabled when all eight PWM channels are
disabled (PWME7-0 = 0). This is useful for reducing power by disabling the prescale counter.
Clock A and clock B are scaled values of the input clock. The value is software selectable for both clock
A and clock B and has options of 1, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, or 1/128 times the bus clock. The value
selected for clock A is determined by the PCKA2, PCKA1, PCKA0 bits in the PWMPRCLK register. The
value selected for clock B is determined by the PCKB2, PCKB1, PCKB0 bits also in the PWMPRCLK
register.
13.4.1.2
Clock Scale
The scaled A clock uses clock A as an input and divides it further with a user programmable value and
then divides this by 2. The scaled B clock uses clock B as an input and divides it further with a user
programmable value and then divides this by 2. The rates available for clock SA are software selectable to
be clock A divided by 2, 4, 6, 8,..., or 512 in increments of divide by 2. Similar rates are available for clock
SB.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
383
Pulse-Width Modulator (S12PWM8B8CV1)
Clock A
PCKA2
PCKA1
PCKA0
Clock A/2, A/4, A/6,....A/512
8-Bit Down
Counter
M
U
X
Load
DIV 2
Clock to
PWM Ch 0
PCLK0
Count = 1
PWMSCLA
M
U
X
Clock SA
PCLK1
M
U
X
M
Clock to
PWM Ch 1
Clock to
PWM Ch 2
U
PCLK2
M
U
X
2 4 8 16 32 64 128
Divide by
Prescaler Taps:
X
PCLK3
Clock B
Clock B/2, B/4, B/6,....B/512
M
U
X
Clock to
PWM Ch 4
PCLK4
M
Count = 1
8-Bit Down
Counter
U
X
M
U
X
Load
PWMSCLB
DIV 2
Clock SB
PCKB2
PCKB1
PCKB0
Clock to
PWM Ch 5
PCLK5
M
U
X
Clock to
PWM Ch 6
PCLK6
PWME7-0
Bus Clock
PFRZ
Freeze Mode Signal
Clock to
PWM Ch 3
M
U
X
Clock to
PWM Ch 7
PCLK7
Prescale
Scale
Clock Select
Figure 13-18. PWM Clock Select Block Diagram
S12XS Family Reference Manual, Rev. 1.10
384
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
Clock A is used as an input to an 8-bit down counter. This down counter loads a user programmable scale
value from the scale register (PWMSCLA). When the down counter reaches one, a pulse is output and the
8-bit counter is re-loaded. The output signal from this circuit is further divided by two. This gives a greater
range with only a slight reduction in granularity. Clock SA equals clock A divided by two times the value
in the PWMSCLA register.
NOTE
Clock SA = Clock A / (2 * PWMSCLA)
When PWMSCLA = $00, PWMSCLA value is considered a full scale value
of 256. Clock A is thus divided by 512.
Similarly, clock B is used as an input to an 8-bit down counter followed by a divide by two producing clock
SB. Thus, clock SB equals clock B divided by two times the value in the PWMSCLB register.
NOTE
Clock SB = Clock B / (2 * PWMSCLB)
When PWMSCLB = $00, PWMSCLB value is considered a full scale value
of 256. Clock B is thus divided by 512.
As an example, consider the case in which the user writes $FF into the PWMSCLA register. Clock A for
this case will be E divided by 4. A pulse will occur at a rate of once every 255x4 E cycles. Passing this
through the divide by two circuit produces a clock signal at an E divided by 2040 rate. Similarly, a value
of $01 in the PWMSCLA register when clock A is E divided by 4 will produce a clock at an E divided by
8 rate.
Writing to PWMSCLA or PWMSCLB causes the associated 8-bit down counter to be re-loaded.
Otherwise, when changing rates the counter would have to count down to $01 before counting at the proper
rate. Forcing the associated counter to re-load the scale register value every time PWMSCLA or
PWMSCLB is written prevents this.
NOTE
Writing to the scale registers while channels are operating can cause
irregularities in the PWM outputs.
13.4.1.3
Clock Select
Each PWM channel has the capability of selecting one of two clocks. For channels 0, 1, 4, and 5 the clock
choices are clock A or clock SA. For channels 2, 3, 6, and 7 the choices are clock B or clock SB. The clock
selection is done with the PCLKx control bits in the PWMCLK register.
NOTE
Changing clock control bits while channels are operating can cause
irregularities in the PWM outputs.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
385
Pulse-Width Modulator (S12PWM8B8CV1)
13.4.2
PWM Channel Timers
The main part of the PWM module are the actual timers. Each of the timer channels has a counter, a period
register and a duty register (each are 8-bit). The waveform output period is controlled by a match between
the period register and the value in the counter. The duty is controlled by a match between the duty register
and the counter value and causes the state of the output to change during the period. The starting polarity
of the output is also selectable on a per channel basis. Shown below in Figure 13-19 is the block diagram
for the PWM timer.
Clock Source
From Port PWMP
Data Register
8-Bit Counter
Gate
PWMCNTx
(Clock Edge
Sync)
Up/Down
Reset
8-bit Compare =
T
M
U
X
M
U
X
Q
PWMDTYx
Q
R
To Pin
Driver
8-bit Compare =
PWMPERx
PPOLx
Q
T
CAEx
Q
R
PWMEx
Figure 13-19. PWM Timer Channel Block Diagram
13.4.2.1
PWM Enable
Each PWM channel has an enable bit (PWMEx) to start its waveform output. When any of the PWMEx
bits are set (PWMEx = 1), the associated PWM output signal is enabled immediately. However, the actual
PWM waveform is not available on the associated PWM output until its clock source begins its next cycle
due to the synchronization of PWMEx and the clock source. An exception to this is when channels are
concatenated. Refer to Section 13.4.2.7, “PWM 16-Bit Functions” for more detail.
NOTE
The first PWM cycle after enabling the channel can be irregular.
S12XS Family Reference Manual, Rev. 1.10
386
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
On the front end of the PWM timer, the clock is enabled to the PWM circuit by the PWMEx bit being high.
There is an edge-synchronizing circuit to guarantee that the clock will only be enabled or disabled at an
edge. When the channel is disabled (PWMEx = 0), the counter for the channel does not count.
13.4.2.2
PWM Polarity
Each channel has a polarity bit to allow starting a waveform cycle with a high or low signal. This is shown
on the block diagram as a mux select of either the Q output or the Q output of the PWM output flip flop.
When one of the bits in the PWMPOL register is set, the associated PWM channel output is high at the
beginning of the waveform, then goes low when the duty count is reached. Conversely, if the polarity bit
is zero, the output starts low and then goes high when the duty count is reached.
13.4.2.3
PWM Period and Duty
Dedicated period and duty registers exist for each channel and are double buffered so that if they change
while the channel is enabled, the change will NOT take effect until one of the following occurs:
• The effective period ends
• The counter is written (counter resets to $00)
• The channel is disabled
In this way, the output of the PWM will always be either the old waveform or the new waveform, not some
variation in between. If the channel is not enabled, then writes to the period and duty registers will go
directly to the latches as well as the buffer.
A change in duty or period can be forced into effect “immediately” by writing the new value to the duty
and/or period registers and then writing to the counter. This forces the counter to reset and the new duty
and/or period values to be latched. In addition, since the counter is readable, it is possible to know where
the count is with respect to the duty value and software can be used to make adjustments
NOTE
When forcing a new period or duty into effect immediately, an irregular
PWM cycle can occur.
Depending on the polarity bit, the duty registers will contain the count of
either the high time or the low time.
13.4.2.4
PWM Timer Counters
Each channel has a dedicated 8-bit up/down counter which runs at the rate of the selected clock source (see
Section 13.4.1, “PWM Clock Select” for the available clock sources and rates). The counter compares to
two registers, a duty register and a period register as shown in Figure 13-19. When the PWM counter
matches the duty register, the output flip-flop changes state, causing the PWM waveform to also change
state. A match between the PWM counter and the period register behaves differently depending on what
output mode is selected as shown in Figure 13-19 and described in Section 13.4.2.5, “Left Aligned
Outputs” and Section 13.4.2.6, “Center Aligned Outputs”.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
387
Pulse-Width Modulator (S12PWM8B8CV1)
Each channel counter can be read at anytime without affecting the count or the operation of the PWM
channel.
Any value written to the counter causes the counter to reset to $00, the counter direction to be set to up,
the immediate load of both duty and period registers with values from the buffers, and the output to change
according to the polarity bit. When the channel is disabled (PWMEx = 0), the counter stops. When a
channel becomes enabled (PWMEx = 1), the associated PWM counter continues from the count in the
PWMCNTx register. This allows the waveform to continue where it left off when the channel is reenabled. When the channel is disabled, writing “0” to the period register will cause the counter to reset on
the next selected clock.
NOTE
If the user wants to start a new “clean” PWM waveform without any
“history” from the old waveform, the user must write to channel counter
(PWMCNTx) prior to enabling the PWM channel (PWMEx = 1).
Generally, writes to the counter are done prior to enabling a channel in order to start from a known state.
However, writing a counter can also be done while the PWM channel is enabled (counting). The effect is
similar to writing the counter when the channel is disabled, except that the new period is started
immediately with the output set according to the polarity bit.
NOTE
Writing to the counter while the channel is enabled can cause an irregular
PWM cycle to occur.
The counter is cleared at the end of the effective period (see Section 13.4.2.5, “Left Aligned Outputs” and
Section 13.4.2.6, “Center Aligned Outputs” for more details).
Table 13-10. PWM Timer Counter Conditions
Counter Clears ($00)
Counter Counts
Counter Stops
When PWMCNTx register written to
any value
When PWM channel is enabled
(PWMEx = 1). Counts from last value in
PWMCNTx.
When PWM channel is disabled
(PWMEx = 0)
Effective period ends
13.4.2.5
Left Aligned Outputs
The PWM timer provides the choice of two types of outputs, left aligned or center aligned. They are
selected with the CAEx bits in the PWMCAE register. If the CAEx bit is cleared (CAEx = 0), the
corresponding PWM output will be left aligned.
In left aligned output mode, the 8-bit counter is configured as an up counter only. It compares to two
registers, a duty register and a period register as shown in the block diagram in Figure 13-19. When the
PWM counter matches the duty register the output flip-flop changes state causing the PWM waveform to
also change state. A match between the PWM counter and the period register resets the counter and the
output flip-flop, as shown in Figure 13-19, as well as performing a load from the double buffer period and
duty register to the associated registers, as described in Section 13.4.2.3, “PWM Period and Duty”. The
counter counts from 0 to the value in the period register – 1.
S12XS Family Reference Manual, Rev. 1.10
388
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
NOTE
Changing the PWM output mode from left aligned to center aligned output
(or vice versa) while channels are operating can cause irregularities in the
PWM output. It is recommended to program the output mode before
enabling the PWM channel.
PPOLx = 0
PPOLx = 1
PWMDTYx
Period = PWMPERx
Figure 13-20. PWM Left Aligned Output Waveform
To calculate the output frequency in left aligned output mode for a particular channel, take the selected
clock source frequency for the channel (A, B, SA, or SB) and divide it by the value in the period register
for that channel.
• PWMx Frequency = Clock (A, B, SA, or SB) / PWMPERx
• PWMx Duty Cycle (high time as a% of period):
— Polarity = 0 (PPOLx = 0)
• Duty Cycle = [(PWMPERx-PWMDTYx)/PWMPERx] * 100%
— Polarity = 1 (PPOLx = 1)
Duty Cycle = [PWMDTYx / PWMPERx] * 100%
As an example of a left aligned output, consider the following case:
Clock Source = E, where E = 10 MHz (100 ns period)
PPOLx = 0
PWMPERx = 4
PWMDTYx = 1
PWMx Frequency = 10 MHz/4 = 2.5 MHz
PWMx Period = 400 ns
PWMx Duty Cycle = 3/4 *100% = 75%
The output waveform generated is shown in Figure 13-21.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
389
Pulse-Width Modulator (S12PWM8B8CV1)
E = 100 ns
Duty Cycle = 75%
Period = 400 ns
Figure 13-21. PWM Left Aligned Output Example Waveform
13.4.2.6
Center Aligned Outputs
For center aligned output mode selection, set the CAEx bit (CAEx = 1) in the PWMCAE register and the
corresponding PWM output will be center aligned.
The 8-bit counter operates as an up/down counter in this mode and is set to up whenever the counter is
equal to $00. The counter compares to two registers, a duty register and a period register as shown in the
block diagram in Figure 13-19. When the PWM counter matches the duty register, the output flip-flop
changes state, causing the PWM waveform to also change state. A match between the PWM counter and
the period register changes the counter direction from an up-count to a down-count. When the PWM
counter decrements and matches the duty register again, the output flip-flop changes state causing the
PWM output to also change state. When the PWM counter decrements and reaches zero, the counter
direction changes from a down-count back to an up-count and a load from the double buffer period and
duty registers to the associated registers is performed, as described in Section 13.4.2.3, “PWM Period and
Duty”. The counter counts from 0 up to the value in the period register and then back down to 0. Thus the
effective period is PWMPERx*2.
NOTE
Changing the PWM output mode from left aligned to center aligned output
(or vice versa) while channels are operating can cause irregularities in the
PWM output. It is recommended to program the output mode before
enabling the PWM channel.
PPOLx = 0
PPOLx = 1
PWMDTYx
PWMDTYx
PWMPERx
PWMPERx
Period = PWMPERx*2
Figure 13-22. PWM Center Aligned Output Waveform
S12XS Family Reference Manual, Rev. 1.10
390
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
To calculate the output frequency in center aligned output mode for a particular channel, take the selected
clock source frequency for the channel (A, B, SA, or SB) and divide it by twice the value in the period
register for that channel.
• PWMx Frequency = Clock (A, B, SA, or SB) / (2*PWMPERx)
• PWMx Duty Cycle (high time as a% of period):
— Polarity = 0 (PPOLx = 0)
Duty Cycle = [(PWMPERx-PWMDTYx)/PWMPERx] * 100%
— Polarity = 1 (PPOLx = 1)
Duty Cycle = [PWMDTYx / PWMPERx] * 100%
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
391
Pulse-Width Modulator (S12PWM8B8CV1)
As an example of a center aligned output, consider the following case:
Clock Source = E, where E = 10 MHz (100 ns period)
PPOLx = 0
PWMPERx = 4
PWMDTYx = 1
PWMx Frequency = 10 MHz/8 = 1.25 MHz
PWMx Period = 800 ns
PWMx Duty Cycle = 3/4 *100% = 75%
Shown in Figure 13-23 is the output waveform generated.
E = 100 ns
E = 100 ns
DUTY CYCLE = 75%
PERIOD = 800 ns
Figure 13-23. PWM Center Aligned Output Example Waveform
13.4.2.7
PWM 16-Bit Functions
The PWM timer also has the option of generating 8-channels of 8-bits or 4-channels of 16-bits for greater
PWM resolution. This 16-bit channel option is achieved through the concatenation of two 8-bit channels.
The PWMCTL register contains four control bits, each of which is used to concatenate a pair of PWM
channels into one 16-bit channel. Channels 6 and 7 are concatenated with the CON67 bit, channels 4 and
5 are concatenated with the CON45 bit, channels 2 and 3 are concatenated with the CON23 bit, and
channels 0 and 1 are concatenated with the CON01 bit.
NOTE
Change these bits only when both corresponding channels are disabled.
When channels 6 and 7 are concatenated, channel 6 registers become the high order bytes of the double
byte channel, as shown in Figure 13-24. Similarly, when channels 4 and 5 are concatenated, channel 4
registers become the high order bytes of the double byte channel. When channels 2 and 3 are concatenated,
channel 2 registers become the high order bytes of the double byte channel. When channels 0 and 1 are
concatenated, channel 0 registers become the high order bytes of the double byte channel.
When using the 16-bit concatenated mode, the clock source is determined by the low order 8-bit channel
clock select control bits. That is channel 7 when channels 6 and 7 are concatenated, channel 5 when
channels 4 and 5 are concatenated, channel 3 when channels 2 and 3 are concatenated, and channel 1 when
channels 0 and 1 are concatenated. The resulting PWM is output to the pins of the corresponding low order
8-bit channel as also shown in Figure 13-24. The polarity of the resulting PWM output is controlled by the
PPOLx bit of the corresponding low order 8-bit channel as well.
S12XS Family Reference Manual, Rev. 1.10
392
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
Clock Source 7
High
Low
PWMCNT6
PWCNT7
Period/Duty Compare
PWM7
Clock Source 5
High
Low
PWMCNT4
PWCNT5
Period/Duty Compare
PWM5
Clock Source 3
High
Low
PWMCNT2
PWCNT3
Period/Duty Compare
PWM3
Clock Source 1
High
Low
PWMCNT0
PWCNT1
Period/Duty Compare
PWM1
Figure 13-24. PWM 16-Bit Mode
Once concatenated mode is enabled (CONxx bits set in PWMCTL register), enabling/disabling the
corresponding 16-bit PWM channel is controlled by the low order PWMEx bit. In this case, the high order
bytes PWMEx bits have no effect and their corresponding PWM output is disabled.
In concatenated mode, writes to the 16-bit counter by using a 16-bit access or writes to either the low or
high order byte of the counter will reset the 16-bit counter. Reads of the 16-bit counter must be made by
16-bit access to maintain data coherency.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
393
Pulse-Width Modulator (S12PWM8B8CV1)
Either left aligned or center aligned output mode can be used in concatenated mode and is controlled by
the low order CAEx bit. The high order CAEx bit has no effect.
Table 13-11 is used to summarize which channels are used to set the various control bits when in 16-bit
mode.
Table 13-11. 16-bit Concatenation Mode Summary
13.4.2.8
CONxx
PWMEx
PPOLx
PCLKx
CAEx
PWMx
Output
CON67
PWME7
PPOL7
PCLK7
CAE7
PWM7
CON45
PWME5
PPOL5
PCLK5
CAE5
PWM5
CON23
PWME3
PPOL3
PCLK3
CAE3
PWM3
CON01
PWME1
PPOL1
PCLK1
CAE1
PWM1
PWM Boundary Cases
Table 13-12 summarizes the boundary conditions for the PWM regardless of the output mode (left aligned
or center aligned) and 8-bit (normal) or 16-bit (concatenation).
Table 13-12. PWM Boundary Cases
13.5
PWMDTYx
PWMPERx
PPOLx
PWMx Output
$00
(indicates no duty)
>$00
1
Always low
$00
(indicates no duty)
>$00
0
Always high
XX
$001
(indicates no period)
1
Always high
XX
$001
(indicates no period)
0
Always low
>= PWMPERx
XX
1
Always high
>= PWMPERx
XX
Counter
=
$00
and
does
not
count.
1
0
Always low
Resets
The reset state of each individual bit is listed within the Section 13.3.2, “Register Descriptions” which
details the registers and their bit-fields. All special functions or modes which are initialized during or just
following reset are described within this section.
• The 8-bit up/down counter is configured as an up counter out of reset.
• All the channels are disabled and all the counters do not count.
S12XS Family Reference Manual, Rev. 1.10
394
Freescale Semiconductor
Pulse-Width Modulator (S12PWM8B8CV1)
13.6
Interrupts
The PWM module has only one interrupt which is generated at the time of emergency shutdown, if the
corresponding enable bit (PWMIE) is set. This bit is the enable for the interrupt. The interrupt flag PWMIF
is set whenever the input level of the PWM7 channel changes while PWM7ENA = 1 or when PWMENA
is being asserted while the level at PWM7 is active.
In stop mode or wait mode (with the PSWAI bit set), the emergency shutdown feature will drive the PWM
outputs to their shutdown output levels but the PWMIF flag will not be set.
A description of the registers involved and affected due to this interrupt is explained in Section 13.3.2.15,
“PWM Shutdown Register (PWMSDN)”.
The PWM block only generates the interrupt and does not service it. The interrupt signal name is PWM
interrupt signal.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
395
Pulse-Width Modulator (S12PWM8B8CV1)
S12XS Family Reference Manual, Rev. 1.10
396
Freescale Semiconductor
Chapter 14
Serial Communication Interface (S12SCIV5)
Table 14-1. Revision History
Version
Number
Revision
Date
05.01
04/16/2004
05.02
10/14/2005
05.03
12/25/2008
05.04
08/05/2009
14.1
Effective
Date
Author
Description of Changes
Update OR and PF flag description; Correct baud rate
tolerance in 4.7.5.1 and 4.7.5.2; Clean up classification and
NDA message banners
Correct alternative registers address;
Remove unavailable baud rate in Table1-16
remove redundancy comments in Figure1-2
fix typo, SCIBDL reset value be 0x04, not 0x00
Introduction
This block guide provides an overview of the serial communication interface (SCI) module.
The SCI allows asynchronous serial communications with peripheral devices and other CPUs.
14.1.1
Glossary
IR: InfraRed
IrDA: Infrared Design Associate
IRQ: Interrupt Request
LIN: Local Interconnect Network
LSB: Least Significant Bit
MSB: Most Significant Bit
NRZ: Non-Return-to-Zero
RZI: Return-to-Zero-Inverted
RXD: Receive Pin
SCI : Serial Communication Interface
TXD: Transmit Pin
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
397
Serial Communication Interface (S12SCIV5)
14.1.2
Features
The SCI includes these distinctive features:
• Full-duplex or single-wire operation
• Standard mark/space non-return-to-zero (NRZ) format
• Selectable IrDA 1.4 return-to-zero-inverted (RZI) format with programmable pulse widths
• 13-bit baud rate selection
• Programmable 8-bit or 9-bit data format
• Separately enabled transmitter and receiver
• Programmable polarity for transmitter and receiver
• Programmable transmitter output parity
• Two receiver wakeup methods:
— Idle line wakeup
— Address mark wakeup
• Interrupt-driven operation with eight flags:
— Transmitter empty
— Transmission complete
— Receiver full
— Idle receiver input
— Receiver overrun
— Noise error
— Framing error
— Parity error
— Receive wakeup on active edge
— Transmit collision detect supporting LIN
— Break Detect supporting LIN
• Receiver framing error detection
• Hardware parity checking
• 1/16 bit-time noise detection
14.1.3
Modes of Operation
The SCI functions the same in normal, special, and emulation modes. It has two low power modes, wait
and stop modes.
• Run mode
• Wait mode
• Stop mode
S12XS Family Reference Manual, Rev. 1.10
398
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.1.4
Block Diagram
Figure 14-1 is a high level block diagram of the SCI module, showing the interaction of various function
blocks.
SCI Data Register
RXD Data In
Infrared
Decoder
Receive Shift Register
Receive & Wakeup
Control
Bus Clock
Baud Rate
Generator
IDLE
Receive
RDRF/OR
Interrupt
Generation BRKD
RXEDG
BERR
Data Format Control
1/16
Transmit Control
Transmit Shift Register
SCI
Interrupt
Request
Transmit
TDRE
Interrupt
Generation TC
Infrared
Encoder
Data Out TXD
SCI Data Register
Figure 14-1. SCI Block Diagram
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
399
Serial Communication Interface (S12SCIV5)
14.2
External Signal Description
The SCI module has a total of two external pins.
14.2.1
TXD — Transmit Pin
The TXD pin transmits SCI (standard or infrared) data. It will idle high in either mode and is high
impedance anytime the transmitter is disabled.
14.2.2
RXD — Receive Pin
The RXD pin receives SCI (standard or infrared) data. An idle line is detected as a line high. This input is
ignored when the receiver is disabled and should be terminated to a known voltage.
14.3
Memory Map and Register Definition
This section provides a detailed description of all the SCI registers.
14.3.1
Module Memory Map and Register Definition
The memory map for the SCI module is given below in Figure 14-2. The address listed for each register is
the address offset. The total address for each register is the sum of the base address for the SCI module and
the address offset for each register.
S12XS Family Reference Manual, Rev. 1.10
400
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.3.2
Register Descriptions
This section consists of register descriptions in address order. Each description includes a standard register
diagram with an associated figure number. Writes to a reserved register locations do not have any effect
and reads of these locations return a zero. Details of register bit and field function follow the register
diagrams, in bit order.
Register
Name
0x0000
SCIBDH1
W
0x0001
SCIBDL1
W
0x0002
SCICR11
R
R
R
W
0x0000
SCIASR12
W
0x0001
SCIACR12
W
0x0002
SCIACR22
0x0003
SCICR2
0x0004
SCISR1
0x0005
SCISR2
0x0006
SCIDRH
0x0007
SCIDRL
R
R
Bit 7
6
5
4
3
2
1
Bit 0
IREN
TNP1
TNP0
SBR12
SBR11
SBR10
SBR9
SBR8
SBR7
SBR6
SBR5
SBR4
SBR3
SBR2
SBR1
SBR0
LOOPS
SCISWAI
RSRC
M
WAKE
ILT
PE
PT
0
0
0
0
BERRV
BERRIF
BKDIF
0
0
0
0
BERRIE
BKDIE
0
0
0
0
0
BERRM1
BERRM0
BKDFE
TIE
TCIE
RIE
ILIE
TE
RE
RWU
SBK
TDRE
TC
RDRF
IDLE
OR
NF
FE
PF
0
0
TXPOL
RXPOL
BRK13
TXDIR
0
0
0
0
0
0
RXEDGIF
RXEDGIE
R
W
R
W
R
0
W
R
W
R
AMAP
R8
W
T8
RAF
R
R7
R6
R5
R4
R3
R2
R1
R0
W
T7
T6
T5
T4
T3
T2
T1
T0
1.These registers are accessible if the AMAP bit in the SCISR2 register is set to zero.
2,These registers are accessible if the AMAP bit in the SCISR2 register is set to one.
= Unimplemented or Reserved
Figure 14-2. SCI Register Summary
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
401
Serial Communication Interface (S12SCIV5)
14.3.2.1
SCI Baud Rate Registers (SCIBDH, SCIBDL)
Module Base + 0x0000
R
W
Reset
7
6
5
4
3
2
1
0
IREN
TNP1
TNP0
SBR12
SBR11
SBR10
SBR9
SBR8
0
0
0
0
0
0
0
0
Figure 14-3. SCI Baud Rate Register (SCIBDH)
Module Base + 0x0001
R
W
Reset
7
6
5
4
3
2
1
0
SBR7
SBR6
SBR5
SBR4
SBR3
SBR2
SBR1
SBR0
0
0
0
0
0
1
0
0
Figure 14-4. SCI Baud Rate Register (SCIBDL)
Read: Anytime, if AMAP = 0. If only SCIBDH is written to, a read will not return the correct data until
SCIBDL is written to as well, following a write to SCIBDH.
Write: Anytime, if AMAP = 0.
NOTE
Those two registers are only visible in the memory map if AMAP = 0 (reset
condition).
The SCI baud rate register is used by to determine the baud rate of the SCI, and to control the infrared
modulation/demodulation submodule.
Table 14-2. SCIBDH and SCIBDL Field Descriptions
Field
7
IREN
Description
Infrared Enable Bit — This bit enables/disables the infrared modulation/demodulation submodule.
0 IR disabled
1 IR enabled
6:5
TNP[1:0]
Transmitter Narrow Pulse Bits — These bits enable whether the SCI transmits a 1/16, 3/16, 1/32 or 1/4 narrow
pulse. See Table 14-3.
4:0
7:0
SBR[12:0]
SCI Baud Rate Bits — The baud rate for the SCI is determined by the bits in this register. The baud rate is
calculated two different ways depending on the state of the IREN bit.
The formulas for calculating the baud rate are:
When IREN = 0 then,
SCI baud rate = SCI bus clock / (16 x SBR[12:0])
When IREN = 1 then,
SCI baud rate = SCI bus clock / (32 x SBR[12:1])
Note: The baud rate generator is disabled after reset and not started until the TE bit or the RE bit is set for the
first time. The baud rate generator is disabled when (SBR[12:0] = 0 and IREN = 0) or (SBR[12:1] = 0 and
IREN = 1).
Note: Writing to SCIBDH has no effect without writing to SCIBDL, because writing to SCIBDH puts the data in
a temporary location until SCIBDL is written to.
S12XS Family Reference Manual, Rev. 1.10
402
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
Table 14-3. IRSCI Transmit Pulse Width
14.3.2.2
TNP[1:0]
Narrow Pulse Width
11
1/4
10
1/32
01
1/16
00
3/16
SCI Control Register 1 (SCICR1)
Module Base + 0x0002
R
W
Reset
7
6
5
4
3
2
1
0
LOOPS
SCISWAI
RSRC
M
WAKE
ILT
PE
PT
0
0
0
0
0
0
0
0
Figure 14-5. SCI Control Register 1 (SCICR1)
Read: Anytime, if AMAP = 0.
Write: Anytime, if AMAP = 0.
NOTE
This register is only visible in the memory map if AMAP = 0 (reset
condition).
Table 14-4. SCICR1 Field Descriptions
Field
Description
7
LOOPS
Loop Select Bit — LOOPS enables loop operation. In loop operation, the RXD pin is disconnected from the SCI
and the transmitter output is internally connected to the receiver input. Both the transmitter and the receiver must
be enabled to use the loop function.
0 Normal operation enabled
1 Loop operation enabled
The receiver input is determined by the RSRC bit.
6
SCISWAI
5
RSRC
4
M
3
WAKE
SCI Stop in Wait Mode Bit — SCISWAI disables the SCI in wait mode.
0 SCI enabled in wait mode
1 SCI disabled in wait mode
Receiver Source Bit — When LOOPS = 1, the RSRC bit determines the source for the receiver shift register
input. See Table 14-5.
0 Receiver input internally connected to transmitter output
1 Receiver input connected externally to transmitter
Data Format Mode Bit — MODE determines whether data characters are eight or nine bits long.
0 One start bit, eight data bits, one stop bit
1 One start bit, nine data bits, one stop bit
Wakeup Condition Bit — WAKE determines which condition wakes up the SCI: a logic 1 (address mark) in the
most significant bit position of a received data character or an idle condition on the RXD pin.
0 Idle line wakeup
1 Address mark wakeup
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
403
Serial Communication Interface (S12SCIV5)
Table 14-4. SCICR1 Field Descriptions (continued)
Field
Description
2
ILT
Idle Line Type Bit — ILT determines when the receiver starts counting logic 1s as idle character bits. The
counting begins either after the start bit or after the stop bit. If the count begins after the start bit, then a string of
logic 1s preceding the stop bit may cause false recognition of an idle character. Beginning the count after the
stop bit avoids false idle character recognition, but requires properly synchronized transmissions.
0 Idle character bit count begins after start bit
1 Idle character bit count begins after stop bit
1
PE
Parity Enable Bit — PE enables the parity function. When enabled, the parity function inserts a parity bit in the
most significant bit position.
0 Parity function disabled
1 Parity function enabled
0
PT
Parity Type Bit — PT determines whether the SCI generates and checks for even parity or odd parity. With even
parity, an even number of 1s clears the parity bit and an odd number of 1s sets the parity bit. With odd parity, an
odd number of 1s clears the parity bit and an even number of 1s sets the parity bit.
1 Even parity
1 Odd parity
Table 14-5. Loop Functions
LOOPS
RSRC
Function
0
x
Normal operation
1
0
Loop mode with transmitter output internally connected to receiver input
1
1
Single-wire mode with TXD pin connected to receiver input
S12XS Family Reference Manual, Rev. 1.10
404
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.3.2.3
SCI Alternative Status Register 1 (SCIASR1)
Module Base + 0x0000
7
R
W
Reset
RXEDGIF
0
6
5
4
3
2
0
0
0
0
BERRV
0
0
0
0
0
1
0
BERRIF
BKDIF
0
0
= Unimplemented or Reserved
Figure 14-6. SCI Alternative Status Register 1 (SCIASR1)
Read: Anytime, if AMAP = 1
Write: Anytime, if AMAP = 1
Table 14-6. SCIASR1 Field Descriptions
Field
7
RXEDGIF
Description
Receive Input Active Edge Interrupt Flag — RXEDGIF is asserted, if an active edge (falling if RXPOL = 0,
rising if RXPOL = 1) on the RXD input occurs. RXEDGIF bit is cleared by writing a “1” to it.
0 No active receive on the receive input has occurred
1 An active edge on the receive input has occurred
2
BERRV
Bit Error Value — BERRV reflects the state of the RXD input when the bit error detect circuitry is enabled and
a mismatch to the expected value happened. The value is only meaningful, if BERRIF = 1.
0 A low input was sampled, when a high was expected
1 A high input reassembled, when a low was expected
1
BERRIF
Bit Error Interrupt Flag — BERRIF is asserted, when the bit error detect circuitry is enabled and if the value
sampled at the RXD input does not match the transmitted value. If the BERRIE interrupt enable bit is set an
interrupt will be generated. The BERRIF bit is cleared by writing a “1” to it.
0 No mismatch detected
1 A mismatch has occurred
0
BKDIF
Break Detect Interrupt Flag — BKDIF is asserted, if the break detect circuitry is enabled and a break signal is
received. If the BKDIE interrupt enable bit is set an interrupt will be generated. The BKDIF bit is cleared by writing
a “1” to it.
0 No break signal was received
1 A break signal was received
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
405
Serial Communication Interface (S12SCIV5)
14.3.2.4
SCI Alternative Control Register 1 (SCIACR1)
Module Base + 0x0001
7
R
W
Reset
RXEDGIE
0
6
5
4
3
2
0
0
0
0
0
0
0
0
0
0
1
0
BERRIE
BKDIE
0
0
= Unimplemented or Reserved
Figure 14-7. SCI Alternative Control Register 1 (SCIACR1)
Read: Anytime, if AMAP = 1
Write: Anytime, if AMAP = 1
Table 14-7. SCIACR1 Field Descriptions
Field
Description
7
RSEDGIE
Receive Input Active Edge Interrupt Enable — RXEDGIE enables the receive input active edge interrupt flag,
RXEDGIF, to generate interrupt requests.
0 RXEDGIF interrupt requests disabled
1 RXEDGIF interrupt requests enabled
1
BERRIE
0
BKDIE
Bit Error Interrupt Enable — BERRIE enables the bit error interrupt flag, BERRIF, to generate interrupt
requests.
0 BERRIF interrupt requests disabled
1 BERRIF interrupt requests enabled
Break Detect Interrupt Enable — BKDIE enables the break detect interrupt flag, BKDIF, to generate interrupt
requests.
0 BKDIF interrupt requests disabled
1 BKDIF interrupt requests enabled
S12XS Family Reference Manual, Rev. 1.10
406
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.3.2.5
SCI Alternative Control Register 2 (SCIACR2)
Module Base + 0x0002
R
7
6
5
4
3
0
0
0
0
0
0
0
0
0
W
Reset
0
2
1
0
BERRM1
BERRM0
BKDFE
0
0
0
= Unimplemented or Reserved
Figure 14-8. SCI Alternative Control Register 2 (SCIACR2)
Read: Anytime, if AMAP = 1
Write: Anytime, if AMAP = 1
Table 14-8. SCIACR2 Field Descriptions
Field
Description
2:1
Bit Error Mode — Those two bits determines the functionality of the bit error detect feature. See Table 14-9.
BERRM[1:0]
0
BKDFE
Break Detect Feature Enable — BKDFE enables the break detect circuitry.
0 Break detect circuit disabled
1 Break detect circuit enabled
Table 14-9. Bit Error Mode Coding
BERRM1
BERRM0
Function
0
0
Bit error detect circuit is disabled
0
1
Receive input sampling occurs during the 9th time tick of a transmitted bit
(refer to Figure 14-19)
1
0
Receive input sampling occurs during the 13th time tick of a transmitted bit
(refer to Figure 14-19)
1
1
Reserved
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
407
Serial Communication Interface (S12SCIV5)
14.3.2.6
SCI Control Register 2 (SCICR2)
Module Base + 0x0003
R
W
Reset
7
6
5
4
3
2
1
0
TIE
TCIE
RIE
ILIE
TE
RE
RWU
SBK
0
0
0
0
0
0
0
0
Figure 14-9. SCI Control Register 2 (SCICR2)
Read: Anytime
Write: Anytime
Table 14-10. SCICR2 Field Descriptions
Field
7
TIE
Description
Transmitter Interrupt Enable Bit — TIE enables the transmit data register empty flag, TDRE, to generate
interrupt requests.
0 TDRE interrupt requests disabled
1 TDRE interrupt requests enabled
6
TCIE
Transmission Complete Interrupt Enable Bit — TCIE enables the transmission complete flag, TC, to generate
interrupt requests.
0 TC interrupt requests disabled
1 TC interrupt requests enabled
5
RIE
Receiver Full Interrupt Enable Bit — RIE enables the receive data register full flag, RDRF, or the overrun flag,
OR, to generate interrupt requests.
0 RDRF and OR interrupt requests disabled
1 RDRF and OR interrupt requests enabled
4
ILIE
Idle Line Interrupt Enable Bit — ILIE enables the idle line flag, IDLE, to generate interrupt requests.
0 IDLE interrupt requests disabled
1 IDLE interrupt requests enabled
3
TE
Transmitter Enable Bit — TE enables the SCI transmitter and configures the TXD pin as being controlled by
the SCI. The TE bit can be used to queue an idle preamble.
0 Transmitter disabled
1 Transmitter enabled
2
RE
Receiver Enable Bit — RE enables the SCI receiver.
0 Receiver disabled
1 Receiver enabled
1
RWU
Receiver Wakeup Bit — Standby state
0 Normal operation.
1 RWU enables the wakeup function and inhibits further receiver interrupt requests. Normally, hardware wakes
the receiver by automatically clearing RWU.
0
SBK
Send Break Bit — Toggling SBK sends one break character (10 or 11 logic 0s, respectively 13 or 14 logics 0s
if BRK13 is set). Toggling implies clearing the SBK bit before the break character has finished transmitting. As
long as SBK is set, the transmitter continues to send complete break characters (10 or 11 bits, respectively 13
or 14 bits).
0 No break characters
1 Transmit break characters
S12XS Family Reference Manual, Rev. 1.10
408
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.3.2.7
SCI Status Register 1 (SCISR1)
The SCISR1 and SCISR2 registers provides inputs to the MCU for generation of SCI interrupts. Also,
these registers can be polled by the MCU to check the status of these bits. The flag-clearing procedures
require that the status register be read followed by a read or write to the SCI data register.It is permissible
to execute other instructions between the two steps as long as it does not compromise the handling of I/O,
but the order of operations is important for flag clearing.
Module Base + 0x0004
R
7
6
5
4
3
2
1
0
TDRE
TC
RDRF
IDLE
OR
NF
FE
PF
1
0
0
0
0
0
0
W
Reset
1
= Unimplemented or Reserved
Figure 14-10. SCI Status Register 1 (SCISR1)
Read: Anytime
Write: Has no meaning or effect
Table 14-11. SCISR1 Field Descriptions
Field
Description
7
TDRE
Transmit Data Register Empty Flag — TDRE is set when the transmit shift register receives a byte from the
SCI data register. When TDRE is 1, the transmit data register (SCIDRH/L) is empty and can receive a new value
to transmit.Clear TDRE by reading SCI status register 1 (SCISR1), with TDRE set and then writing to SCI data
register low (SCIDRL).
0 No byte transferred to transmit shift register
1 Byte transferred to transmit shift register; transmit data register empty
6
TC
Transmit Complete Flag — TC is set low when there is a transmission in progress or when a preamble or break
character is loaded. TC is set high when the TDRE flag is set and no data, preamble, or break character is being
transmitted.When TC is set, the TXD pin becomes idle (logic 1). Clear TC by reading SCI status register 1
(SCISR1) with TC set and then writing to SCI data register low (SCIDRL). TC is cleared automatically when data,
preamble, or break is queued and ready to be sent. TC is cleared in the event of a simultaneous set and clear of
the TC flag (transmission not complete).
0 Transmission in progress
1 No transmission in progress
5
RDRF
Receive Data Register Full Flag — RDRF is set when the data in the receive shift register transfers to the SCI
data register. Clear RDRF by reading SCI status register 1 (SCISR1) with RDRF set and then reading SCI data
register low (SCIDRL).
0 Data not available in SCI data register
1 Received data available in SCI data register
4
IDLE
Idle Line Flag — IDLE is set when 10 consecutive logic 1s (if M = 0) or 11 consecutive logic 1s (if M =1) appear
on the receiver input. Once the IDLE flag is cleared, a valid frame must again set the RDRF flag before an idle
condition can set the IDLE flag.Clear IDLE by reading SCI status register 1 (SCISR1) with IDLE set and then
reading SCI data register low (SCIDRL).
0 Receiver input is either active now or has never become active since the IDLE flag was last cleared
1 Receiver input has become idle
Note: When the receiver wakeup bit (RWU) is set, an idle line condition does not set the IDLE flag.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
409
Serial Communication Interface (S12SCIV5)
Table 14-11. SCISR1 Field Descriptions (continued)
Field
Description
3
OR
Overrun Flag — OR is set when software fails to read the SCI data register before the receive shift register
receives the next frame. The OR bit is set immediately after the stop bit has been completely received for the
second frame. The data in the shift register is lost, but the data already in the SCI data registers is not affected.
Clear OR by reading SCI status register 1 (SCISR1) with OR set and then reading SCI data register low
(SCIDRL).
0 No overrun
1 Overrun
Note: OR flag may read back as set when RDRF flag is clear. This may happen if the following sequence of
events occurs:
1. After the first frame is received, read status register SCISR1 (returns RDRF set and OR flag clear);
2. Receive second frame without reading the first frame in the data register (the second frame is not
received and OR flag is set);
3. Read data register SCIDRL (returns first frame and clears RDRF flag in the status register);
4. Read status register SCISR1 (returns RDRF clear and OR set).
Event 3 may be at exactly the same time as event 2 or any time after. When this happens, a dummy
SCIDRL read following event 4 will be required to clear the OR flag if further frames are to be received.
2
NF
Noise Flag — NF is set when the SCI detects noise on the receiver input. NF bit is set during the same cycle as
the RDRF flag but does not get set in the case of an overrun. Clear NF by reading SCI status register 1(SCISR1),
and then reading SCI data register low (SCIDRL).
0 No noise
1 Noise
1
FE
Framing Error Flag — FE is set when a logic 0 is accepted as the stop bit. FE bit is set during the same cycle
as the RDRF flag but does not get set in the case of an overrun. FE inhibits further data reception until it is
cleared. Clear FE by reading SCI status register 1 (SCISR1) with FE set and then reading the SCI data register
low (SCIDRL).
0 No framing error
1 Framing error
0
PF
Parity Error Flag — PF is set when the parity enable bit (PE) is set and the parity of the received data does not
match the parity type bit (PT). PF bit is set during the same cycle as the RDRF flag but does not get set in the
case of an overrun. Clear PF by reading SCI status register 1 (SCISR1), and then reading SCI data register low
(SCIDRL).
0 No parity error
1 Parity error
S12XS Family Reference Manual, Rev. 1.10
410
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.3.2.8
SCI Status Register 2 (SCISR2)
Module Base + 0x0005
7
R
W
Reset
AMAP
0
6
5
0
0
0
0
4
3
2
1
TXPOL
RXPOL
BRK13
TXDIR
0
0
0
0
0
RAF
0
= Unimplemented or Reserved
Figure 14-11. SCI Status Register 2 (SCISR2)
Read: Anytime
Write: Anytime
Table 14-12. SCISR2 Field Descriptions
Field
Description
7
AMAP
Alternative Map — This bit controls which registers sharing the same address space are accessible. In the reset
condition the SCI behaves as previous versions. Setting AMAP=1 allows the access to another set of control and
status registers and hides the baud rate and SCI control Register 1.
0 The registers labelled SCIBDH (0x0000),SCIBDL (0x0001), SCICR1 (0x0002) are accessible
1 The registers labelled SCIASR1 (0x0000),SCIACR1 (0x0001), SCIACR2 (0x00002) are accessible
4
TXPOL
Transmit Polarity — This bit control the polarity of the transmitted data. In NRZ format, a one is represented by
a mark and a zero is represented by a space for normal polarity, and the opposite for inverted polarity. In IrDA
format, a zero is represented by short high pulse in the middle of a bit time remaining idle low for a one for normal
polarity, and a zero is represented by short low pulse in the middle of a bit time remaining idle high for a one for
inverted polarity.
0 Normal polarity
1 Inverted polarity
3
RXPOL
Receive Polarity — This bit control the polarity of the received data. In NRZ format, a one is represented by a
mark and a zero is represented by a space for normal polarity, and the opposite for inverted polarity. In IrDA
format, a zero is represented by short high pulse in the middle of a bit time remaining idle low for a one for normal
polarity, and a zero is represented by short low pulse in the middle of a bit time remaining idle high for a one for
inverted polarity.
0 Normal polarity
1 Inverted polarity
2
BRK13
Break Transmit Character Length — This bit determines whether the transmit break character is 10 or 11 bit
respectively 13 or 14 bits long. The detection of a framing error is not affected by this bit.
0 Break character is 10 or 11 bit long
1 Break character is 13 or 14 bit long
1
TXDIR
Transmitter Pin Data Direction in Single-Wire Mode — This bit determines whether the TXD pin is going to
be used as an input or output, in the single-wire mode of operation. This bit is only relevant in the single-wire
mode of operation.
0 TXD pin to be used as an input in single-wire mode
1 TXD pin to be used as an output in single-wire mode
0
RAF
Receiver Active Flag — RAF is set when the receiver detects a logic 0 during the RT1 time period of the start
bit search. RAF is cleared when the receiver detects an idle character.
0 No reception in progress
1 Reception in progress
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
411
Serial Communication Interface (S12SCIV5)
14.3.2.9
SCI Data Registers (SCIDRH, SCIDRL)
Module Base + 0x0006
7
R
6
R8
W
Reset
0
T8
0
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 14-12. SCI Data Registers (SCIDRH)
Module Base + 0x0007
7
6
5
4
3
2
1
0
R
R7
R6
R5
R4
R3
R2
R1
R0
W
T7
T6
T5
T4
T3
T2
T1
T0
0
0
0
0
0
0
0
0
Reset
Figure 14-13. SCI Data Registers (SCIDRL)
Read: Anytime; reading accesses SCI receive data register
Write: Anytime; writing accesses SCI transmit data register; writing to R8 has no effect
Table 14-13. SCIDRH and SCIDRL Field Descriptions
Field
Description
SCIDRH
7
R8
Received Bit 8 — R8 is the ninth data bit received when the SCI is configured for 9-bit data format (M = 1).
SCIDRH
6
T8
Transmit Bit 8 — T8 is the ninth data bit transmitted when the SCI is configured for 9-bit data format (M = 1).
SCIDRL
7:0
R[7:0]
T[7:0]
R7:R0 — Received bits seven through zero for 9-bit or 8-bit data formats
T7:T0 — Transmit bits seven through zero for 9-bit or 8-bit formats
NOTE
If the value of T8 is the same as in the previous transmission, T8 does not
have to be rewritten.The same value is transmitted until T8 is rewritten
In 8-bit data format, only SCI data register low (SCIDRL) needs to be
accessed.
When transmitting in 9-bit data format and using 8-bit write instructions,
write first to SCI data register high (SCIDRH), then SCIDRL.
S12XS Family Reference Manual, Rev. 1.10
412
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.4
Functional Description
This section provides a complete functional description of the SCI block, detailing the operation of the
design from the end user perspective in a number of subsections.
Figure 14-14 shows the structure of the SCI module. The SCI allows full duplex, asynchronous, serial
communication between the CPU and remote devices, including other CPUs. The SCI transmitter and
receiver operate independently, although they use the same baud rate generator. The CPU monitors the
status of the SCI, writes the data to be transmitted, and processes received data.
R8
IREN
SCI Data
Register
NF
FE
Ir_RXD
Bus
Clock
Receive
Shift Register
SCRXD
Receive
and Wakeup
Control
PF
RAF
RE
IDLE
RWU
RDRF
LOOPS
OR
RSRC
M
Baud Rate
Generator
IDLE
ILIE
RDRF/OR
Infrared
Receive
Decoder
R16XCLK
RXD
RIE
TIE
WAKE
Data Format
Control
ILT
PE
SBR12:SBR0
TDRE
TDRE
TC
SCI
Interrupt
Request
PT
TC
TCIE
TE
÷16
Transmit
Control
LOOPS
SBK
RSRC
T8
Transmit
Shift Register
RXEDGIE
Active Edge
Detect
RXEDGIF
BKDIF
RXD
SCI Data
Register
Break Detect
BKDFE
SCTXD
BKDIE
LIN Transmit BERRIF
Collision
Detect
BERRIE
R16XCLK
Infrared
Transmit
Encoder
BERRM[1:0]
Ir_TXD
TXD
R32XCLK
TNP[1:0]
IREN
Figure 14-14. Detailed SCI Block Diagram
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
413
Serial Communication Interface (S12SCIV5)
14.4.1
Infrared Interface Submodule
This module provides the capability of transmitting narrow pulses to an IR LED and receiving narrow
pulses and transforming them to serial bits, which are sent to the SCI. The IrDA physical layer
specification defines a half-duplex infrared communication link for exchange data. The full standard
includes data rates up to 16 Mbits/s. This design covers only data rates between 2.4 Kbits/s and 115.2
Kbits/s.
The infrared submodule consists of two major blocks: the transmit encoder and the receive decoder. The
SCI transmits serial bits of data which are encoded by the infrared submodule to transmit a narrow pulse
for every zero bit. No pulse is transmitted for every one bit. When receiving data, the IR pulses should be
detected using an IR photo diode and transformed to CMOS levels by the IR receive decoder (external
from the MCU). The narrow pulses are then stretched by the infrared submodule to get back to a serial bit
stream to be received by the SCI.The polarity of transmitted pulses and expected receive pulses can be
inverted so that a direct connection can be made to external IrDA transceiver modules that uses active low
pulses.
The infrared submodule receives its clock sources from the SCI. One of these two clocks are selected in
the infrared submodule in order to generate either 3/16, 1/16, 1/32 or 1/4 narrow pulses during
transmission. The infrared block receives two clock sources from the SCI, R16XCLK and R32XCLK,
which are configured to generate the narrow pulse width during transmission. The R16XCLK and
R32XCLK are internal clocks with frequencies 16 and 32 times the baud rate respectively. Both
R16XCLK and R32XCLK clocks are used for transmitting data. The receive decoder uses only the
R16XCLK clock.
14.4.1.1
Infrared Transmit Encoder
The infrared transmit encoder converts serial bits of data from transmit shift register to the TXD pin. A
narrow pulse is transmitted for a zero bit and no pulse for a one bit. The narrow pulse is sent in the middle
of the bit with a duration of 1/32, 1/16, 3/16 or 1/4 of a bit time. A narrow high pulse is transmitted for a
zero bit when TXPOL is cleared, while a narrow low pulse is transmitted for a zero bit when TXPOL is set.
14.4.1.2
Infrared Receive Decoder
The infrared receive block converts data from the RXD pin to the receive shift register. A narrow pulse is
expected for each zero received and no pulse is expected for each one received. A narrow high pulse is
expected for a zero bit when RXPOL is cleared, while a narrow low pulse is expected for a zero bit when
RXPOL is set. This receive decoder meets the edge jitter requirement as defined by the IrDA serial infrared
physical layer specification.
14.4.2
LIN Support
This module provides some basic support for the LIN protocol. At first this is a break detect circuitry
making it easier for the LIN software to distinguish a break character from an incoming data stream. As a
further addition is supports a collision detection at the bit level as well as cancelling pending transmissions.
S12XS Family Reference Manual, Rev. 1.10
414
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.4.3
Data Format
The SCI uses the standard NRZ mark/space data format. When Infrared is enabled, the SCI uses RZI data
format where zeroes are represented by light pulses and ones remain low. See Figure 14-15 below.
8-Bit Data Format
(Bit M in SCICR1 Clear)
Start
Bit
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Possible
Parity
Bit
Bit 6
STOP
Bit
Bit 7
Next
Start
Bit
Standard
SCI Data
Infrared
SCI Data
9-Bit Data Format
(Bit M in SCICR1 Set)
Start
Bit
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
POSSIBLE
PARITY
Bit
Bit 6
Bit 7
Bit 8
STOP
Bit
NEXT
START
Bit
Standard
SCI Data
Infrared
SCI Data
Figure 14-15. SCI Data Formats
Each data character is contained in a frame that includes a start bit, eight or nine data bits, and a stop bit.
Clearing the M bit in SCI control register 1 configures the SCI for 8-bit data characters. A frame with eight
data bits has a total of 10 bits. Setting the M bit configures the SCI for nine-bit data characters. A frame
with nine data bits has a total of 11 bits.
Table 14-14. Example of 8-Bit Data Formats
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
1
8
0
0
1
1
7
0
1
1
1
1
0
1
1
7
1
The address bit identifies the frame as an address
character. See Section 14.4.6.6, “Receiver Wakeup”.
When the SCI is configured for 9-bit data characters, the ninth data bit is the T8 bit in SCI data register
high (SCIDRH). It remains unchanged after transmission and can be used repeatedly without rewriting it.
A frame with nine data bits has a total of 11 bits.
Table 14-15. Example of 9-Bit Data Formats
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
1
9
0
0
1
1
8
0
1
1
8
1
0
1
1
1
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
415
Serial Communication Interface (S12SCIV5)
1
14.4.4
The address bit identifies the frame as an address
character. See Section 14.4.6.6, “Receiver Wakeup”.
Baud Rate Generation
A 13-bit modulus counter in the baud rate generator derives the baud rate for both the receiver and the
transmitter. The value from 0 to 8191 written to the SBR12:SBR0 bits determines the bus clock divisor.
The SBR bits are in the SCI baud rate registers (SCIBDH and SCIBDL). The baud rate clock is
synchronized with the bus clock and drives the receiver. The baud rate clock divided by 16 drives the
transmitter. The receiver has an acquisition rate of 16 samples per bit time.
Baud rate generation is subject to one source of error:
• Integer division of the bus clock may not give the exact target frequency.
Table 14-16 lists some examples of achieving target baud rates with a bus clock frequency of 25 MHz.
When IREN = 0 then,
SCI baud rate = SCI bus clock / (16 * SCIBR[12:0])
Table 14-16. Baud Rates (Example: Bus Clock = 25 MHz)
Bits
SBR[12:0]
Receiver
Clock (Hz)
Transmitter
Clock (Hz)
Target
Baud Rate
Error
(%)
41
609,756.1
38,109.8
38,400
.76
81
308,642.0
19,290.1
19,200
.47
163
153,374.2
9585.9
9,600
.16
326
76,687.1
4792.9
4,800
.15
651
38,402.5
2400.2
2,400
.01
1302
19,201.2
1200.1
1,200
.01
2604
9600.6
600.0
600
.00
5208
4800.0
300.0
300
.00
S12XS Family Reference Manual, Rev. 1.10
416
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.4.5
Transmitter
Internal Bus
Bus
Clock
÷ 16
Baud Divider
SCI Data Registers
11-Bit Transmit Register
H
8
7
6
5
4
3
2
1
0
TXPOL
SCTXD
L
MSB
M
Start
Stop
SBR12:SBR0
LOOP
CONTROL
TIE
TDRE IRQ
Break (All 0s)
Parity
Generation
Preamble (All 1s)
PT
Shift Enable
PE
Load from SCIDR
T8
To Receiver
LOOPS
RSRC
TDRE
Transmitter Control
TC
TC IRQ
TCIE
TE
BERRIF
BER IRQ
TCIE
SBK
BERRM[1:0]
Transmit
Collision Detect
SCTXD
SCRXD
(From Receiver)
Figure 14-16. Transmitter Block Diagram
14.4.5.1
Transmitter Character Length
The SCI transmitter can accommodate either 8-bit or 9-bit data characters. The state of the M bit in SCI
control register 1 (SCICR1) determines the length of data characters. When transmitting 9-bit data, bit T8
in SCI data register high (SCIDRH) is the ninth bit (bit 8).
14.4.5.2
Character Transmission
To transmit data, the MCU writes the data bits to the SCI data registers (SCIDRH/SCIDRL), which in turn
are transferred to the transmitter shift register. The transmit shift register then shifts a frame out through
the TXD pin, after it has prefaced them with a start bit and appended them with a stop bit. The SCI data
registers (SCIDRH and SCIDRL) are the write-only buffers between the internal data bus and the transmit
shift register.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
417
Serial Communication Interface (S12SCIV5)
The SCI also sets a flag, the transmit data register empty flag (TDRE), every time it transfers data from the
buffer (SCIDRH/L) to the transmitter shift register.The transmit driver routine may respond to this flag by
writing another byte to the Transmitter buffer (SCIDRH/SCIDRL), while the shift register is still shifting
out the first byte.
To initiate an SCI transmission:
1. Configure the SCI:
a) Select a baud rate. Write this value to the SCI baud registers (SCIBDH/L) to begin the baud
rate generator. Remember that the baud rate generator is disabled when the baud rate is zero.
Writing to the SCIBDH has no effect without also writing to SCIBDL.
b) Write to SCICR1 to configure word length, parity, and other configuration bits
(LOOPS,RSRC,M,WAKE,ILT,PE,PT).
c) Enable the transmitter, interrupts, receive, and wake up as required, by writing to the SCICR2
register bits (TIE,TCIE,RIE,ILIE,TE,RE,RWU,SBK). A preamble or idle character will now
be shifted out of the transmitter shift register.
2. Transmit Procedure for each byte:
a) Poll the TDRE flag by reading the SCISR1 or responding to the TDRE interrupt. Keep in mind
that the TDRE bit resets to one.
b) If the TDRE flag is set, write the data to be transmitted to SCIDRH/L, where the ninth bit is
written to the T8 bit in SCIDRH if the SCI is in 9-bit data format. A new transmission will not
result until the TDRE flag has been cleared.
3. Repeat step 2 for each subsequent transmission.
NOTE
The TDRE flag is set when the shift register is loaded with the next data to
be transmitted from SCIDRH/L, which happens, generally speaking, a little
over half-way through the stop bit of the previous frame. Specifically, this
transfer occurs 9/16ths of a bit time AFTER the start of the stop bit of the
previous frame.
Writing the TE bit from 0 to a 1 automatically loads the transmit shift register with a preamble of 10 logic
1s (if M = 0) or 11 logic 1s (if M = 1). After the preamble shifts out, control logic transfers the data from
the SCI data register into the transmit shift register. A logic 0 start bit automatically goes into the least
significant bit position of the transmit shift register. A logic 1 stop bit goes into the most significant bit
position.
Hardware supports odd or even parity. When parity is enabled, the most significant bit (MSB) of the data
character is the parity bit.
The transmit data register empty flag, TDRE, in SCI status register 1 (SCISR1) becomes set when the SCI
data register transfers a byte to the transmit shift register. The TDRE flag indicates that the SCI data
register can accept new data from the internal data bus. If the transmit interrupt enable bit, TIE, in SCI
control register 2 (SCICR2) is also set, the TDRE flag generates a transmitter interrupt request.
S12XS Family Reference Manual, Rev. 1.10
418
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
When the transmit shift register is not transmitting a frame, the TXD pin goes to the idle condition, logic
1. If at any time software clears the TE bit in SCI control register 2 (SCICR2), the transmitter enable signal
goes low and the transmit signal goes idle.
If software clears TE while a transmission is in progress (TC = 0), the frame in the transmit shift register
continues to shift out. To avoid accidentally cutting off the last frame in a message, always wait for TDRE
to go high after the last frame before clearing TE.
To separate messages with preambles with minimum idle line time, use this sequence between messages:
1. Write the last byte of the first message to SCIDRH/L.
2. Wait for the TDRE flag to go high, indicating the transfer of the last frame to the transmit shift
register.
3. Queue a preamble by clearing and then setting the TE bit.
4. Write the first byte of the second message to SCIDRH/L.
14.4.5.3
Break Characters
Writing a logic 1 to the send break bit, SBK, in SCI control register 2 (SCICR2) loads the transmit shift
register with a break character. A break character contains all logic 0s and has no start, stop, or parity bit.
Break character length depends on the M bit in SCI control register 1 (SCICR1). As long as SBK is at logic
1, transmitter logic continuously loads break characters into the transmit shift register. After software
clears the SBK bit, the shift register finishes transmitting the last break character and then transmits at least
one logic 1. The automatic logic 1 at the end of a break character guarantees the recognition of the start bit
of the next frame.
The SCI recognizes a break character when there are 10 or 11(M = 0 or M = 1) consecutive zero received.
Depending if the break detect feature is enabled or not receiving a break character has these effects on SCI
registers.
If the break detect feature is disabled (BKDFE = 0):
• Sets the framing error flag, FE
• Sets the receive data register full flag, RDRF
• Clears the SCI data registers (SCIDRH/L)
• May set the overrun flag, OR, noise flag, NF, parity error flag, PE, or the receiver active flag, RAF
(see 3.4.4 and 3.4.5 SCI Status Register 1 and 2)
If the break detect feature is enabled (BKDFE = 1) there are two scenarios1
The break is detected right from a start bit or is detected during a byte reception.
• Sets the break detect interrupt flag, BLDIF
• Does not change the data register full flag, RDRF or overrun flag OR
• Does not change the framing error flag FE, parity error flag PE.
• Does not clear the SCI data registers (SCIDRH/L)
• May set noise flag NF, or receiver active flag RAF.
1.
A Break character in this context are either 10 or 11 consecutive zero received bits
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
419
Serial Communication Interface (S12SCIV5)
Figure 14-17 shows two cases of break detect. In trace RXD_1 the break symbol starts with the start bit,
while in RXD_2 the break starts in the middle of a transmission. If BRKDFE = 1, in RXD_1 case there
will be no byte transferred to the receive buffer and the RDRF flag will not be modified. Also no framing
error or parity error will be flagged from this transfer. In RXD_2 case, however the break signal starts later
during the transmission. At the expected stop bit position the byte received so far will be transferred to the
receive buffer, the receive data register full flag will be set, a framing error and if enabled and appropriate
a parity error will be set. Once the break is detected the BRKDIF flag will be set.
Start Bit Position
Stop Bit Position
BRKDIF = 1
RXD_1
Zero Bit Counter
1
2
3
4
5
6
7
8
9
10 . . .
BRKDIF = 1
FE = 1
RXD_2
Zero Bit Counter
1
2
3
4
5
6
7
8
9
10
...
Figure 14-17. Break Detection if BRKDFE = 1 (M = 0)
14.4.5.4
Idle Characters
An idle character (or preamble) contains all logic 1s and has no start, stop, or parity bit. Idle character
length depends on the M bit in SCI control register 1 (SCICR1). The preamble is a synchronizing idle
character that begins the first transmission initiated after writing the TE bit from 0 to 1.
If the TE bit is cleared during a transmission, the TXD pin becomes idle after completion of the
transmission in progress. Clearing and then setting the TE bit during a transmission queues an idle
character to be sent after the frame currently being transmitted.
NOTE
When queueing an idle character, return the TE bit to logic 1 before the stop
bit of the current frame shifts out through the TXD pin. Setting TE after the
stop bit appears on TXD causes data previously written to the SCI data
register to be lost. Toggle the TE bit for a queued idle character while the
TDRE flag is set and immediately before writing the next byte to the SCI
data register.
If the TE bit is clear and the transmission is complete, the SCI is not the
master of the TXD pin
S12XS Family Reference Manual, Rev. 1.10
420
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.4.5.5
LIN Transmit Collision Detection
This module allows to check for collisions on the LIN bus.
LIN Physical Interface
Synchronizer Stage
Receive Shift
Register
Compare
RXD Pin
Bit Error
LIN Bus
Bus Clock
Sample
Point
Transmit Shift
Register
TXD Pin
Figure 14-18. Collision Detect Principle
If the bit error circuit is enabled (BERRM[1:0] = 0:1 or = 1:0]), the error detect circuit will compare the
transmitted and the received data stream at a point in time and flag any mismatch. The timing checks run
when transmitter is active (not idle). As soon as a mismatch between the transmitted data and the received
data is detected the following happens:
• The next bit transmitted will have a high level (TXPOL = 0) or low level (TXPOL = 1)
• The transmission is aborted and the byte in transmit buffer is discarded.
• the transmit data register empty and the transmission complete flag will be set
• The bit error interrupt flag, BERRIF, will be set.
• No further transmissions will take place until the BERRIF is cleared.
4
5
6
7
8
BERRM[1:0] = 0:1
9
10
11
12
13
14
15
0
Sampling End
3
Sampling Begin
Input Receive
Shift Register
2
Sampling End
Output Transmit
Shift Register
1
Sampling Begin
0
BERRM[1:0] = 1:1
Compare Sample Points
Figure 14-19. Timing Diagram Bit Error Detection
If the bit error detect feature is disabled, the bit error interrupt flag is cleared.
NOTE
The RXPOL and TXPOL bit should be set the same when transmission
collision detect feature is enabled, otherwise the bit error interrupt flag may
be set incorrectly.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
421
Serial Communication Interface (S12SCIV5)
14.4.6
Receiver
Internal Bus
SBR12:SBR0
RXPOL
Data
Recovery
Loop
Control
H
Start
11-Bit Receive Shift Register
8
7
6
5
4
3
2
1
0
L
All 1s
SCRXD
From TXD Pin
or Transmitter
Stop
Baud Divider
MSB
Bus
Clock
SCI Data Register
RE
RAF
LOOPS
RSRC
FE
M
WAKE
ILT
PE
PT
RWU
NF
Wakeup
Logic
PE
R8
Parity
Checking
Idle IRQ
IDLE
ILIE
BRKDFE
OR
Break
Detect Logic
RIE
BRKDIF
BRKDIE
Active Edge
Detect Logic
RDRF/OR
IRQ
RDRF
Break IRQ
RXEDGIF
RXEDGIE
RX Active Edge IRQ
Figure 14-20. SCI Receiver Block Diagram
14.4.6.1
Receiver Character Length
The SCI receiver can accommodate either 8-bit or 9-bit data characters. The state of the M bit in SCI
control register 1 (SCICR1) determines the length of data characters. When receiving 9-bit data, bit R8 in
SCI data register high (SCIDRH) is the ninth bit (bit 8).
14.4.6.2
Character Reception
During an SCI reception, the receive shift register shifts a frame in from the RXD pin. The SCI data register
is the read-only buffer between the internal data bus and the receive shift register.
After a complete frame shifts into the receive shift register, the data portion of the frame transfers to the
SCI data register. The receive data register full flag, RDRF, in SCI status register 1 (SCISR1) becomes set,
S12XS Family Reference Manual, Rev. 1.10
422
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
indicating that the received byte can be read. If the receive interrupt enable bit, RIE, in SCI control
register 2 (SCICR2) is also set, the RDRF flag generates an RDRF interrupt request.
14.4.6.3
Data Sampling
The RT clock rate. The RT clock is an internal signal with a frequency 16 times the baud rate. To adjust
for baud rate mismatch, the RT clock (see Figure 14-21) is re-synchronized:
• After every start bit
• After the receiver detects a data bit change from logic 1 to logic 0 (after the majority of data bit
samples at RT8, RT9, and RT10 returns a valid logic 1 and the majority of the next RT8, RT9, and
RT10 samples returns a valid logic 0)
To locate the start bit, data recovery logic does an asynchronous search for a logic 0 preceded by three logic
1s.When the falling edge of a possible start bit occurs, the RT clock begins to count to 16.
Start Bit
LSB
RXD
Samples
1
1
1
1
1
1
1
1
0
0
Start Bit
Qualification
0
0
Start Bit
Verification
0
0
0
Data
Sampling
RT4
RT3
RT2
RT1
RT16
RT15
RT14
RT13
RT12
RT11
RT10
RT9
RT8
RT7
RT6
RT5
RT4
RT3
RT2
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT CLock Count
RT1
RT Clock
Reset RT Clock
Figure 14-21. Receiver Data Sampling
To verify the start bit and to detect noise, data recovery logic takes samples at RT3, RT5, and RT7.
Figure 14-17 summarizes the results of the start bit verification samples.
Table 14-17. Start Bit Verification
RT3, RT5, and RT7 Samples
Start Bit Verification
Noise Flag
000
Yes
0
001
Yes
1
010
Yes
1
011
No
0
100
Yes
1
101
No
0
110
No
0
111
No
0
If start bit verification is not successful, the RT clock is reset and a new search for a start bit begins.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
423
Serial Communication Interface (S12SCIV5)
To determine the value of a data bit and to detect noise, recovery logic takes samples at RT8, RT9, and
RT10. Table 14-18 summarizes the results of the data bit samples.
Table 14-18. Data Bit Recovery
RT8, RT9, and RT10 Samples
Data Bit Determination
Noise Flag
000
0
0
001
0
1
010
0
1
011
1
1
100
0
1
101
1
1
110
1
1
111
1
0
NOTE
The RT8, RT9, and RT10 samples do not affect start bit verification. If any
or all of the RT8, RT9, and RT10 start bit samples are logic 1s following a
successful start bit verification, the noise flag (NF) is set and the receiver
assumes that the bit is a start bit (logic 0).
To verify a stop bit and to detect noise, recovery logic takes samples at RT8, RT9, and RT10. Table 14-19
summarizes the results of the stop bit samples.
Table 14-19. Stop Bit Recovery
RT8, RT9, and RT10 Samples
Framing Error Flag
Noise Flag
000
1
0
001
1
1
010
1
1
011
0
1
100
1
1
101
0
1
110
0
1
111
0
0
S12XS Family Reference Manual, Rev. 1.10
424
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
In Figure 14-22 the verification samples RT3 and RT5 determine that the first low detected was noise and
not the beginning of a start bit. The RT clock is reset and the start bit search begins again. The noise flag
is not set because the noise occurred before the start bit was found.
LSB
Start Bit
0
0
0
0
0
0
RT10
1
RT9
RT1
1
RT8
RT1
1
RT7
0
RT1
1
RT1
1
RT5
1
RT1
Samples
RT1
RXD
0
RT3
RT2
RT1
RT16
RT15
RT14
RT13
RT12
RT11
RT6
RT5
RT4
RT3
RT2
RT4
RT3
RT Clock Count
RT2
RT Clock
Reset RT Clock
Figure 14-22. Start Bit Search Example 1
In Figure 14-23, verification sample at RT3 is high. The RT3 sample sets the noise flag. Although the
perceived bit time is misaligned, the data samples RT8, RT9, and RT10 are within the bit time and data
recovery is successful.
Perceived Start Bit
Actual Start Bit
LSB
1
0
RT1
RT1
RT1
RT1
1
0
0
0
0
0
RT10
1
RT9
1
RT8
1
RT7
1
RT1
Samples
RT1
RXD
RT7
RT6
RT5
RT4
RT3
RT2
RT1
RT16
RT15
RT14
RT13
RT12
RT11
RT6
RT5
RT4
RT3
RT Clock Count
RT2
RT Clock
Reset RT Clock
Figure 14-23. Start Bit Search Example 2
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
425
Serial Communication Interface (S12SCIV5)
In Figure 14-24, a large burst of noise is perceived as the beginning of a start bit, although the test sample
at RT5 is high. The RT5 sample sets the noise flag. Although this is a worst-case misalignment of perceived
bit time, the data samples RT8, RT9, and RT10 are within the bit time and data recovery is successful.
Perceived Start Bit
LSB
Actual Start Bit
RT1
RT1
0
1
0
0
0
0
RT10
0
RT9
1
RT8
1
RT7
1
RT1
Samples
RT1
RXD
RT9
RT8
RT7
RT6
RT5
RT4
RT3
RT2
RT1
RT16
RT15
RT14
RT13
RT12
RT11
RT6
RT5
RT4
RT3
RT Clock Count
RT2
RT Clock
Reset RT Clock
Figure 14-24. Start Bit Search Example 3
Figure 14-25 shows the effect of noise early in the start bit time. Although this noise does not affect proper
synchronization with the start bit time, it does set the noise flag.
Perceived and Actual Start Bit
LSB
RT1
RT1
RT1
RT1
1
1
1
1
0
RT1
1
RT1
1
RT1
1
RT1
1
RT1
1
RT1
RXD
Samples
1
0
RT3
RT2
RT1
RT16
RT15
RT14
RT13
RT12
RT11
RT9
RT10
RT8
RT7
RT6
RT5
RT4
RT3
RT Clock Count
RT2
RT Clock
Reset RT Clock
Figure 14-25. Start Bit Search Example 4
S12XS Family Reference Manual, Rev. 1.10
426
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
Figure 14-26 shows a burst of noise near the beginning of the start bit that resets the RT clock. The sample
after the reset is low but is not preceded by three high samples that would qualify as a falling edge.
Depending on the timing of the start bit search and on the data, the frame may be missed entirely or it may
set the framing error flag.
Start Bit
0
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
0
1
1
0
0
0
0
0
0
0
0
RT1
1
RT1
1
RT1
1
RT1
1
RT1
1
RT1
1
RT1
1
RT1
1
RT7
1
RT1
Samples
LSB
No Start Bit Found
RXD
RT1
RT1
RT1
RT1
RT6
RT5
RT4
RT3
RT Clock Count
RT2
RT Clock
Reset RT Clock
Figure 14-26. Start Bit Search Example 5
In Figure 14-27, a noise burst makes the majority of data samples RT8, RT9, and RT10 high. This sets the
noise flag but does not reset the RT clock. In start bits only, the RT8, RT9, and RT10 data samples are
ignored.
Start Bit
LSB
RT1
RT1
1
0
0
0
0
1
0
1
RT10
RT1
1
RT9
RT1
1
RT8
1
RT7
1
RT1
1
RT1
1
RT1
1
RT1
1
RT1
Samples
RT1
RXD
RT3
RT2
RT1
RT16
RT15
RT14
RT13
RT12
RT11
RT6
RT5
RT4
RT3
RT Clock Count
RT2
RT Clock
Reset RT Clock
Figure 14-27. Start Bit Search Example 6
14.4.6.4
Framing Errors
If the data recovery logic does not detect a logic 1 where the stop bit should be in an incoming frame, it
sets the framing error flag, FE, in SCI status register 1 (SCISR1). A break character also sets the FE flag
because a break character has no stop bit. The FE flag is set at the same time that the RDRF flag is set.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
427
Serial Communication Interface (S12SCIV5)
14.4.6.5
Baud Rate Tolerance
A transmitting device may be operating at a baud rate below or above the receiver baud rate. Accumulated
bit time misalignment can cause one of the three stop bit data samples (RT8, RT9, and RT10) to fall outside
the actual stop bit. A noise error will occur if the RT8, RT9, and RT10 samples are not all the same logical
values. A framing error will occur if the receiver clock is misaligned in such a way that the majority of the
RT8, RT9, and RT10 stop bit samples are a logic zero.
As the receiver samples an incoming frame, it re-synchronizes the RT clock on any valid falling edge
within the frame. Re synchronization within frames will correct a misalignment between transmitter bit
times and receiver bit times.
14.4.6.5.1
Slow Data Tolerance
Figure 14-28 shows how much a slow received frame can be misaligned without causing a noise error or
a framing error. The slow stop bit begins at RT8 instead of RT1 but arrives in time for the stop bit data
samples at RT8, RT9, and RT10.
MSB
Stop
RT16
RT15
RT14
RT13
RT12
RT11
RT10
RT9
RT8
RT7
RT6
RT5
RT4
RT3
RT2
RT1
Receiver
RT Clock
Data
Samples
Figure 14-28. Slow Data
Let’s take RTr as receiver RT clock and RTt as transmitter RT clock.
For an 8-bit data character, it takes the receiver 9 bit times x 16 RTr cycles +7 RTr cycles = 151 RTr cycles
to start data sampling of the stop bit.
With the misaligned character shown in Figure 14-28, the receiver counts 151 RTr cycles at the point when
the count of the transmitting device is 9 bit times x 16 RTt cycles = 144 RTt cycles.
The maximum percent difference between the receiver count and the transmitter count of a slow 8-bit data
character with no errors is:
((151 – 144) / 151) x 100 = 4.63%
For a 9-bit data character, it takes the receiver 10 bit times x 16 RTr cycles + 7 RTr cycles = 167 RTr cycles
to start data sampling of the stop bit.
With the misaligned character shown in Figure 14-28, the receiver counts 167 RTr cycles at the point when
the count of the transmitting device is 10 bit times x 16 RTt cycles = 160 RTt cycles.
The maximum percent difference between the receiver count and the transmitter count of a slow 9-bit
character with no errors is:
((167 – 160) / 167) X 100 = 4.19%
S12XS Family Reference Manual, Rev. 1.10
428
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.4.6.5.2
Fast Data Tolerance
Figure 14-29 shows how much a fast received frame can be misaligned. The fast stop bit ends at RT10
instead of RT16 but is still sampled at RT8, RT9, and RT10.
Stop
Idle or Next Frame
RT16
RT15
RT14
RT13
RT12
RT11
RT10
RT9
RT8
RT7
RT6
RT5
RT4
RT3
RT2
RT1
Receiver
RT Clock
Data
Samples
Figure 14-29. Fast Data
For an 8-bit data character, it takes the receiver 9 bit times x 16 RTr cycles + 10 RTr cycles = 154 RTr cycles
to finish data sampling of the stop bit.
With the misaligned character shown in Figure 14-29, the receiver counts 154 RTr cycles at the point when
the count of the transmitting device is 10 bit times x 16 RTt cycles = 160 RTt cycles.
The maximum percent difference between the receiver count and the transmitter count of a fast 8-bit
character with no errors is:
((160 – 154) / 160) x 100 = 3.75%
For a 9-bit data character, it takes the receiver 10 bit times x 16 RTr cycles + 10 RTr cycles = 170 RTr cycles
to finish data sampling of the stop bit.
With the misaligned character shown in Figure 14-29, the receiver counts 170 RTr cycles at the point when
the count of the transmitting device is 11 bit times x 16 RTt cycles = 176 RTt cycles.
The maximum percent difference between the receiver count and the transmitter count of a fast 9-bit
character with no errors is:
((176 – 170) /176) x 100 = 3.40%
14.4.6.6
Receiver Wakeup
To enable the SCI to ignore transmissions intended only for other receivers in multiple-receiver systems,
the receiver can be put into a standby state. Setting the receiver wakeup bit, RWU, in SCI control register 2
(SCICR2) puts the receiver into standby state during which receiver interrupts are disabled.The SCI will
still load the receive data into the SCIDRH/L registers, but it will not set the RDRF flag.
The transmitting device can address messages to selected receivers by including addressing information in
the initial frame or frames of each message.
The WAKE bit in SCI control register 1 (SCICR1) determines how the SCI is brought out of the standby
state to process an incoming message. The WAKE bit enables either idle line wakeup or address mark
wakeup.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
429
Serial Communication Interface (S12SCIV5)
14.4.6.6.1
Idle Input line Wakeup (WAKE = 0)
In this wakeup method, an idle condition on the RXD pin clears the RWU bit and wakes up the SCI. The
initial frame or frames of every message contain addressing information. All receivers evaluate the
addressing information, and receivers for which the message is addressed process the frames that follow.
Any receiver for which a message is not addressed can set its RWU bit and return to the standby state. The
RWU bit remains set and the receiver remains on standby until another idle character appears on the RXD
pin.
Idle line wakeup requires that messages be separated by at least one idle character and that no message
contains idle characters.
The idle character that wakes a receiver does not set the receiver idle bit, IDLE, or the receive data register
full flag, RDRF.
The idle line type bit, ILT, determines whether the receiver begins counting logic 1s as idle character bits
after the start bit or after the stop bit. ILT is in SCI control register 1 (SCICR1).
14.4.6.6.2
Address Mark Wakeup (WAKE = 1)
In this wakeup method, a logic 1 in the most significant bit (MSB) position of a frame clears the RWU bit
and wakes up the SCI. The logic 1 in the MSB position marks a frame as an address frame that contains
addressing information. All receivers evaluate the addressing information, and the receivers for which the
message is addressed process the frames that follow.Any receiver for which a message is not addressed can
set its RWU bit and return to the standby state. The RWU bit remains set and the receiver remains on
standby until another address frame appears on the RXD pin.
The logic 1 MSB of an address frame clears the receiver’s RWU bit before the stop bit is received and sets
the RDRF flag.
Address mark wakeup allows messages to contain idle characters but requires that the MSB be reserved
for use in address frames.
NOTE
With the WAKE bit clear, setting the RWU bit after the RXD pin has been
idle can cause the receiver to wake up immediately.
14.4.7
Single-Wire Operation
Normally, the SCI uses two pins for transmitting and receiving. In single-wire operation, the RXD pin is
disconnected from the SCI. The SCI uses the TXD pin for both receiving and transmitting.
Transmitter
Receiver
TXD
RXD
Figure 14-30. Single-Wire Operation (LOOPS = 1, RSRC = 1)
S12XS Family Reference Manual, Rev. 1.10
430
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
Enable single-wire operation by setting the LOOPS bit and the receiver source bit, RSRC, in SCI control
register 1 (SCICR1). Setting the LOOPS bit disables the path from the RXD pin to the receiver. Setting
the RSRC bit connects the TXD pin to the receiver. Both the transmitter and receiver must be enabled
(TE = 1 and RE = 1).The TXDIR bit (SCISR2[1]) determines whether the TXD pin is going to be used as
an input (TXDIR = 0) or an output (TXDIR = 1) in this mode of operation.
NOTE
In single-wire operation data from the TXD pin is inverted if RXPOL is set.
14.4.8
Loop Operation
In loop operation the transmitter output goes to the receiver input. The RXD pin is disconnected from the
SCI.
Transmitter
TXD
Receiver
RXD
Figure 14-31. Loop Operation (LOOPS = 1, RSRC = 0)
Enable loop operation by setting the LOOPS bit and clearing the RSRC bit in SCI control register 1
(SCICR1). Setting the LOOPS bit disables the path from the RXD pin to the receiver. Clearing the RSRC
bit connects the transmitter output to the receiver input. Both the transmitter and receiver must be enabled
(TE = 1 and RE = 1).
NOTE
In loop operation data from the transmitter is not recognized by the receiver
if RXPOL and TXPOL are not the same.
14.5
Initialization/Application Information
14.5.1
Reset Initialization
See Section 14.3.2, “Register Descriptions”.
14.5.2
14.5.2.1
Modes of Operation
Run Mode
Normal mode of operation.
To initialize a SCI transmission, see Section 14.4.5.2, “Character Transmission”.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
431
Serial Communication Interface (S12SCIV5)
14.5.2.2
Wait Mode
SCI operation in wait mode depends on the state of the SCISWAI bit in the SCI control register 1
(SCICR1).
• If SCISWAI is clear, the SCI operates normally when the CPU is in wait mode.
• If SCISWAI is set, SCI clock generation ceases and the SCI module enters a power-conservation
state when the CPU is in wait mode. Setting SCISWAI does not affect the state of the receiver
enable bit, RE, or the transmitter enable bit, TE.
If SCISWAI is set, any transmission or reception in progress stops at wait mode entry. The
transmission or reception resumes when either an internal or external interrupt brings the CPU out
of wait mode. Exiting wait mode by reset aborts any transmission or reception in progress and
resets the SCI.
14.5.2.3
Stop Mode
The SCI is inactive during stop mode for reduced power consumption. The STOP instruction does not
affect the SCI register states, but the SCI bus clock will be disabled. The SCI operation resumes from
where it left off after an external interrupt brings the CPU out of stop mode. Exiting stop mode by reset
aborts any transmission or reception in progress and resets the SCI.
The receive input active edge detect circuit is still active in stop mode. An active edge on the receive input
can be used to bring the CPU out of stop mode.
14.5.3
Interrupt Operation
This section describes the interrupt originated by the SCI block.The MCU must service the interrupt
requests. Table 14-20 lists the eight interrupt sources of the SCI.
Table 14-20. SCI Interrupt Sources
Interrupt
Source
Local Enable
TDRE
SCISR1[7]
TIE
TC
SCISR1[6]
TCIE
RDRF
SCISR1[5]
RIE
OR
SCISR1[3]
IDLE
SCISR1[4]
RXEDGIF SCIASR1[7]
Description
Active high level. Indicates that a byte was transferred from SCIDRH/L to the
transmit shift register.
Active high level. Indicates that a transmit is complete.
Active high level. The RDRF interrupt indicates that received data is available
in the SCI data register.
Active high level. This interrupt indicates that an overrun condition has occurred.
ILIE
RXEDGIE
Active high level. Indicates that receiver input has become idle.
Active high level. Indicates that an active edge (falling for RXPOL = 0, rising for
RXPOL = 1) was detected.
BERRIF
SCIASR1[1]
BERRIE
Active high level. Indicates that a mismatch between transmitted and received data
in a single wire application has happened.
BKDIF
SCIASR1[0]
BRKDIE
Active high level. Indicates that a break character has been received.
S12XS Family Reference Manual, Rev. 1.10
432
Freescale Semiconductor
Serial Communication Interface (S12SCIV5)
14.5.3.1
Description of Interrupt Operation
The SCI only originates interrupt requests. The following is a description of how the SCI makes a request
and how the MCU should acknowledge that request. The interrupt vector offset and interrupt number are
chip dependent. The SCI only has a single interrupt line (SCI Interrupt Signal, active high operation) and
all the following interrupts, when generated, are ORed together and issued through that port.
14.5.3.1.1
TDRE Description
The TDRE interrupt is set high by the SCI when the transmit shift register receives a byte from the SCI
data register. A TDRE interrupt indicates that the transmit data register (SCIDRH/L) is empty and that a
new byte can be written to the SCIDRH/L for transmission.Clear TDRE by reading SCI status register 1
with TDRE set and then writing to SCI data register low (SCIDRL).
14.5.3.1.2
TC Description
The TC interrupt is set by the SCI when a transmission has been completed. Transmission is completed
when all bits including the stop bit (if transmitted) have been shifted out and no data is queued to be
transmitted. No stop bit is transmitted when sending a break character and the TC flag is set (providing
there is no more data queued for transmission) when the break character has been shifted out. A TC
interrupt indicates that there is no transmission in progress. TC is set high when the TDRE flag is set and
no data, preamble, or break character is being transmitted. When TC is set, the TXD pin becomes idle
(logic 1). Clear TC by reading SCI status register 1 (SCISR1) with TC set and then writing to SCI data
register low (SCIDRL).TC is cleared automatically when data, preamble, or break is queued and ready to
be sent.
14.5.3.1.3
RDRF Description
The RDRF interrupt is set when the data in the receive shift register transfers to the SCI data register. A
RDRF interrupt indicates that the received data has been transferred to the SCI data register and that the
byte can now be read by the MCU. The RDRF interrupt is cleared by reading the SCI status register one
(SCISR1) and then reading SCI data register low (SCIDRL).
14.5.3.1.4
OR Description
The OR interrupt is set when software fails to read the SCI data register before the receive shift register
receives the next frame. The newly acquired data in the shift register will be lost in this case, but the data
already in the SCI data registers is not affected. The OR interrupt is cleared by reading the SCI status
register one (SCISR1) and then reading SCI data register low (SCIDRL).
14.5.3.1.5
IDLE Description
The IDLE interrupt is set when 10 consecutive logic 1s (if M = 0) or 11 consecutive logic 1s (if M = 1)
appear on the receiver input. Once the IDLE is cleared, a valid frame must again set the RDRF flag before
an idle condition can set the IDLE flag. Clear IDLE by reading SCI status register 1 (SCISR1) with IDLE
set and then reading SCI data register low (SCIDRL).
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
433
Serial Communication Interface (S12SCIV5)
14.5.3.1.6
RXEDGIF Description
The RXEDGIF interrupt is set when an active edge (falling if RXPOL = 0, rising if RXPOL = 1) on the
RXD pin is detected. Clear RXEDGIF by writing a “1” to the SCIASR1 SCI alternative status register 1.
14.5.3.1.7
BERRIF Description
The BERRIF interrupt is set when a mismatch between the transmitted and the received data in a single
wire application like LIN was detected. Clear BERRIF by writing a “1” to the SCIASR1 SCI alternative
status register 1. This flag is also cleared if the bit error detect feature is disabled.
14.5.3.1.8
BKDIF Description
The BKDIF interrupt is set when a break signal was received. Clear BKDIF by writing a “1” to the
SCIASR1 SCI alternative status register 1. This flag is also cleared if break detect feature is disabled.
14.5.4
Recovery from Wait Mode
The SCI interrupt request can be used to bring the CPU out of wait mode.
14.5.5
Recovery from Stop Mode
An active edge on the receive input can be used to bring the CPU out of stop mode.
S12XS Family Reference Manual, Rev. 1.10
434
Freescale Semiconductor
Chapter 15
Serial Peripheral Interface (S12SPIV5)
Table 15-1. Revision History
Revision
Number
Revision Date
Sections
Affected
V05.00
24 Mar 2005
15.3.2/15-439
15.1
Description of Changes
- Added 16-bit transfer width feature.
Introduction
The SPI module allows a duplex, synchronous, serial communication between the MCU and peripheral
devices. Software can poll the SPI status flags or the SPI operation can be interrupt driven.
15.1.1
Glossary of Terms
SPI
SS
SCK
MOSI
MISO
MOMI
SISO
15.1.2
Serial Peripheral Interface
Slave Select
Serial Clock
Master Output, Slave Input
Master Input, Slave Output
Master Output, Master Input
Slave Input, Slave Output
Features
The SPI includes these distinctive features:
• Master mode and slave mode
• Selectable 8 or 16-bit transfer width
• Bidirectional mode
• Slave select output
• Mode fault error flag with CPU interrupt capability
• Double-buffered data register
• Serial clock with programmable polarity and phase
• Control of SPI operation during wait mode
15.1.3
Modes of Operation
The SPI functions in three modes: run, wait, and stop.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
435
Serial Peripheral Interface (S12SPIV5)
•
•
•
Run mode
This is the basic mode of operation.
Wait mode
SPI operation in wait mode is a configurable low power mode, controlled by the SPISWAI bit
located in the SPICR2 register. In wait mode, if the SPISWAI bit is clear, the SPI operates like in
run mode. If the SPISWAI bit is set, the SPI goes into a power conservative state, with the SPI clock
generation turned off. If the SPI is configured as a master, any transmission in progress stops, but
is resumed after CPU goes into run mode. If the SPI is configured as a slave, reception and
transmission of data continues, so that the slave stays synchronized to the master.
Stop mode
The SPI is inactive in stop mode for reduced power consumption. If the SPI is configured as a
master, any transmission in progress stops, but is resumed after CPU goes into run mode. If the SPI
is configured as a slave, reception and transmission of data continues, so that the slave stays
synchronized to the master.
For a detailed description of operating modes, please refer to Section 15.4.7, “Low Power Mode Options”.
15.1.4
Block Diagram
Figure 15-1 gives an overview on the SPI architecture. The main parts of the SPI are status, control and
data registers, shifter logic, baud rate generator, master/slave control logic, and port control logic.
S12XS Family Reference Manual, Rev. 1.10
436
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
SPI
2
SPI Control Register 1
BIDIROE
2
SPI Control Register 2
SPC0
SPI Status Register
SPIF MODF SPTEF
Slave
Control
CPOL
CPHA
Phase + SCK In
Slave Baud Rate Polarity
Control
Master Baud Rate
Phase + SCK Out
Polarity
Control
Interrupt Control
SPI
Interrupt
Request
Baud Rate Generator
Master
Control
Counter
Bus Clock
Prescaler Clock Select
SPPR
3
SPR
MOSI
Port
Control
Logic
SCK
SS
Baud Rate
Shift
Clock
Sample
Clock
3
Shifter
SPI Baud Rate Register
Data In
LSBFE=1
LSBFE=0
LSBFE=1
MSB
SPI Data Register
LSBFE=0
LSBFE=0 LSB
LSBFE=1
Data Out
Figure 15-1. SPI Block Diagram
15.2
External Signal Description
This section lists the name and description of all ports including inputs and outputs that do, or may, connect
off chip. The SPI module has a total of four external pins.
15.2.1
MOSI — Master Out/Slave In Pin
This pin is used to transmit data out of the SPI module when it is configured as a master and receive data
when it is configured as slave.
15.2.2
MISO — Master In/Slave Out Pin
This pin is used to transmit data out of the SPI module when it is configured as a slave and receive data
when it is configured as master.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
437
Serial Peripheral Interface (S12SPIV5)
15.2.3
SS — Slave Select Pin
This pin is used to output the select signal from the SPI module to another peripheral with which a data
transfer is to take place when it is configured as a master and it is used as an input to receive the slave select
signal when the SPI is configured as slave.
15.2.4
SCK — Serial Clock Pin
In master mode, this is the synchronous output clock. In slave mode, this is the synchronous input clock.
15.3
Memory Map and Register Definition
This section provides a detailed description of address space and registers used by the SPI.
15.3.1
Module Memory Map
The memory map for the SPI is given in Figure 15-2. The address listed for each register is the sum of a
base address and an address offset. The base address is defined at the SoC level and the address offset is
defined at the module level. Reads from the reserved bits return zeros and writes to the reserved bits have
no effect.
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
SPIE
SPE
SPTIE
MSTR
CPOL
CPHA
SSOE
LSBFE
MODFEN
BIDIROE
SPISWAI
SPC0
SPR2
SPR1
SPR0
0x0000
SPICR1
R
W
0x0001
SPICR2
R
W
0
0x0002
SPIBR
R
W
0
0x0003
SPISR
R
W
0x0004
SPIDRH
XFRW
0
0
0
SPPR2
SPPR1
SPPR0
SPIF
0
SPTEF
MODF
0
0
0
0
R
W
R15
T15
R14
T14
R13
T13
R12
T12
R11
T11
R10
T10
R9
T9
R8
T8
0x0005
SPIDRL
R
W
R7
T7
R6
T6
R5
T5
R4
T4
R3
T3
R2
T2
R1
T1
R0
T0
0x0006
Reserved
R
W
0x0007
Reserved
R
W
= Unimplemented or Reserved
Figure 15-2. SPI Register Summary
S12XS Family Reference Manual, Rev. 1.10
438
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
15.3.2
Register Descriptions
This section consists of register descriptions in address order. Each description includes a standard register
diagram with an associated figure number. Details of register bit and field function follow the register
diagrams, in bit order.
15.3.2.1
SPI Control Register 1 (SPICR1)
Module Base +0x0000
R
W
Reset
7
6
5
4
3
2
1
0
SPIE
SPE
SPTIE
MSTR
CPOL
CPHA
SSOE
LSBFE
0
0
0
0
0
1
0
0
Figure 15-3. SPI Control Register 1 (SPICR1)
Read: Anytime
Write: Anytime
Table 15-2. SPICR1 Field Descriptions
Field
Description
7
SPIE
SPI Interrupt Enable Bit — This bit enables SPI interrupt requests, if SPIF or MODF status flag is set.
0 SPI interrupts disabled.
1 SPI interrupts enabled.
6
SPE
SPI System Enable Bit — This bit enables the SPI system and dedicates the SPI port pins to SPI system
functions. If SPE is cleared, SPI is disabled and forced into idle state, status bits in SPISR register are reset.
0 SPI disabled (lower power consumption).
1 SPI enabled, port pins are dedicated to SPI functions.
5
SPTIE
SPI Transmit Interrupt Enable — This bit enables SPI interrupt requests, if SPTEF flag is set.
0 SPTEF interrupt disabled.
1 SPTEF interrupt enabled.
4
MSTR
SPI Master/Slave Mode Select Bit — This bit selects whether the SPI operates in master or slave mode.
Switching the SPI from master to slave or vice versa forces the SPI system into idle state.
0 SPI is in slave mode.
1 SPI is in master mode.
3
CPOL
SPI Clock Polarity Bit — This bit selects an inverted or non-inverted SPI clock. To transmit data between SPI
modules, the SPI modules must have identical CPOL values. In master mode, a change of this bit will abort a
transmission in progress and force the SPI system into idle state.
0 Active-high clocks selected. In idle state SCK is low.
1 Active-low clocks selected. In idle state SCK is high.
2
CPHA
SPI Clock Phase Bit — This bit is used to select the SPI clock format. In master mode, a change of this bit will
abort a transmission in progress and force the SPI system into idle state.
0 Sampling of data occurs at odd edges (1,3,5,...) of the SCK clock.
1 Sampling of data occurs at even edges (2,4,6,...) of the SCK clock.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
439
Serial Peripheral Interface (S12SPIV5)
Table 15-2. SPICR1 Field Descriptions (continued)
Field
Description
1
SSOE
Slave Select Output Enable — The SS output feature is enabled only in master mode, if MODFEN is set, by
asserting the SSOE as shown in Table 15-3. In master mode, a change of this bit will abort a transmission in
progress and force the SPI system into idle state.
0
LSBFE
LSB-First Enable — This bit does not affect the position of the MSB and LSB in the data register. Reads and
writes of the data register always have the MSB in the highest bit position. In master mode, a change of this bit
will abort a transmission in progress and force the SPI system into idle state.
0 Data is transferred most significant bit first.
1 Data is transferred least significant bit first.
Table 15-3. SS Input / Output Selection
15.3.2.2
MODFEN
SSOE
Master Mode
Slave Mode
0
0
SS not used by SPI
SS input
0
1
SS not used by SPI
SS input
1
0
SS input with MODF feature
SS input
1
1
SS is slave select output
SS input
SPI Control Register 2 (SPICR2)
Module Base +0x0001
7
R
0
W
Reset
0
6
XFRW
0
5
0
0
4
3
MODFEN
BIDIROE
0
0
2
0
0
1
0
SPISWAI
SPC0
0
0
= Unimplemented or Reserved
Figure 15-4. SPI Control Register 2 (SPICR2)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
S12XS Family Reference Manual, Rev. 1.10
440
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
Table 15-4. SPICR2 Field Descriptions
Field
Description
6
XFRW
Transfer Width — This bit is used for selecting the data transfer width. If 8-bit transfer width is selected, SPIDRL
becomes the dedicated data register and SPIDRH is unused. If 16-bit transfer width is selected, SPIDRH and
SPIDRL form a 16-bit data register. Please refer to Section 15.3.2.4, “SPI Status Register (SPISR) for
information about transmit/receive data handling and the interrupt flag clearing mechanism. In master mode, a
change of this bit will abort a transmission in progress and force the SPI system into idle state.
0 8-bit Transfer Width (n = 8)1
1 16-bit Transfer Width (n = 16)1
4
MODFEN
Mode Fault Enable Bit — This bit allows the MODF failure to be detected. If the SPI is in master mode and
MODFEN is cleared, then the SS port pin is not used by the SPI. In slave mode, the SS is available only as an
input regardless of the value of MODFEN. For an overview on the impact of the MODFEN bit on the SS port pin
configuration, refer to Table 15-3. In master mode, a change of this bit will abort a transmission in progress and
force the SPI system into idle state.
0 SS port pin is not used by the SPI.
1 SS port pin with MODF feature.
3
BIDIROE
Output Enable in the Bidirectional Mode of Operation — This bit controls the MOSI and MISO output buffer
of the SPI, when in bidirectional mode of operation (SPC0 is set). In master mode, this bit controls the output
buffer of the MOSI port, in slave mode it controls the output buffer of the MISO port. In master mode, with SPC0
set, a change of this bit will abort a transmission in progress and force the SPI into idle state.
0 Output buffer disabled.
1 Output buffer enabled.
1
SPISWAI
SPI Stop in Wait Mode Bit — This bit is used for power conservation while in wait mode.
0 SPI clock operates normally in wait mode.
1 Stop SPI clock generation when in wait mode.
0
Serial Pin Control Bit 0 — This bit enables bidirectional pin configurations as shown in Table 15-5. In master
SPC0
mode, a change of this bit will abort a transmission in progress and force the SPI system into idle state.
1 n is used later in this document as a placeholder for the selected transfer width.
Table 15-5. Bidirectional Pin Configurations
Pin Mode
SPC0
BIDIROE
MISO
MOSI
Master Mode of Operation
Normal
0
X
Master In
Master Out
Bidirectional
1
0
MISO not used by SPI
Master In
1
Master I/O
Slave Mode of Operation
Normal
0
X
Slave Out
Slave In
Bidirectional
1
0
Slave In
MOSI not used by SPI
1
Slave I/O
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
441
Serial Peripheral Interface (S12SPIV5)
15.3.2.3
SPI Baud Rate Register (SPIBR)
Module Base +0x0002
7
R
0
W
Reset
0
6
5
4
3
SPPR2
SPPR1
SPPR0
0
0
0
0
0
2
1
0
SPR2
SPR1
SPR0
0
0
0
= Unimplemented or Reserved
Figure 15-5. SPI Baud Rate Register (SPIBR)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 15-6. SPIBR Field Descriptions
Field
Description
6–4
SPPR[2:0]
SPI Baud Rate Preselection Bits — These bits specify the SPI baud rates as shown in Table 15-7. In master
mode, a change of these bits will abort a transmission in progress and force the SPI system into idle state.
2–0
SPR[2:0]
SPI Baud Rate Selection Bits — These bits specify the SPI baud rates as shown in Table 15-7. In master mode,
a change of these bits will abort a transmission in progress and force the SPI system into idle state.
The baud rate divisor equation is as follows:
BaudRateDivisor = (SPPR + 1) • 2(SPR + 1)
Eqn. 15-1
The baud rate can be calculated with the following equation:
Baud Rate = BusClock / BaudRateDivisor
Eqn. 15-2
NOTE
For maximum allowed baud rates, please refer to the SPI Electrical
Specification in the Electricals chapter of this data sheet.
Table 15-7. Example SPI Baud Rate Selection (25 MHz Bus Clock) (Sheet 1 of 3)
SPPR2
SPPR1
SPPR0
SPR2
SPR1
SPR0
Baud Rate
Divisor
Baud Rate
0
0
0
0
0
0
2
12.5 Mbit/s
0
0
0
0
0
1
4
6.25 Mbit/s
0
0
0
0
1
0
8
3.125 Mbit/s
0
0
0
0
1
1
16
1.5625 Mbit/s
0
0
0
1
0
0
32
781.25 kbit/s
0
0
0
1
0
1
64
390.63 kbit/s
0
0
0
1
1
0
128
195.31 kbit/s
0
0
0
1
1
1
256
97.66 kbit/s
0
0
1
0
0
0
4
6.25 Mbit/s
0
0
1
0
0
1
8
3.125 Mbit/s
0
0
1
0
1
0
16
1.5625 Mbit/s
0
0
1
0
1
1
32
781.25 kbit/s
S12XS Family Reference Manual, Rev. 1.10
442
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
Table 15-7. Example SPI Baud Rate Selection (25 MHz Bus Clock) (Sheet 2 of 3)
Baud Rate
Divisor
Baud Rate
0
64
390.63 kbit/s
1
128
195.31 kbit/s
1
0
256
97.66 kbit/s
1
1
512
48.83 kbit/s
0
0
0
6
4.16667 Mbit/s
0
0
1
12
2.08333 Mbit/s
0
0
1
0
24
1.04167 Mbit/s
0
0
1
1
48
520.83 kbit/s
1
0
1
0
0
96
260.42 kbit/s
1
0
1
0
1
192
130.21 kbit/s
0
1
0
1
1
0
384
65.10 kbit/s
0
1
0
1
1
1
768
32.55 kbit/s
0
1
1
0
0
0
8
3.125 Mbit/s
0
1
1
0
0
1
16
1.5625 Mbit/s
0
1
1
0
1
0
32
781.25 kbit/s
0
1
1
0
1
1
64
390.63 kbit/s
0
1
1
1
0
0
128
195.31 kbit/s
0
1
1
1
0
1
256
97.66 kbit/s
0
1
1
1
1
0
512
48.83 kbit/s
0
1
1
1
1
1
1024
24.41 kbit/s
1
0
0
0
0
0
10
2.5 Mbit/s
1
0
0
0
0
1
20
1.25 Mbit/s
1
0
0
0
1
0
40
625 kbit/s
1
0
0
0
1
1
80
312.5 kbit/s
1
0
0
1
0
0
160
156.25 kbit/s
1
0
0
1
0
1
320
78.13 kbit/s
1
0
0
1
1
0
640
39.06 kbit/s
1
0
0
1
1
1
1280
19.53 kbit/s
1
0
1
0
0
0
12
2.08333 Mbit/s
1
0
1
0
0
1
24
1.04167 Mbit/s
1
0
1
0
1
0
48
520.83 kbit/s
1
0
1
0
1
1
96
260.42 kbit/s
1
0
1
1
0
0
192
130.21 kbit/s
1
0
1
1
0
1
384
65.10 kbit/s
1
0
1
1
1
0
768
32.55 kbit/s
1
0
1
1
1
1
1536
16.28 kbit/s
1
1
0
0
0
0
14
1.78571 Mbit/s
1
1
0
0
0
1
28
892.86 kbit/s
1
1
0
0
1
0
56
446.43 kbit/s
1
1
0
0
1
1
112
223.21 kbit/s
1
1
0
1
0
0
224
111.61 kbit/s
1
1
0
1
0
1
448
55.80 kbit/s
SPPR2
SPPR1
SPPR0
SPR2
SPR1
SPR0
0
0
1
1
0
0
0
1
1
0
0
0
1
1
0
0
1
1
0
1
0
0
1
0
0
1
0
1
0
0
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
443
Serial Peripheral Interface (S12SPIV5)
Table 15-7. Example SPI Baud Rate Selection (25 MHz Bus Clock) (Sheet 3 of 3)
Baud Rate
Divisor
Baud Rate
0
896
27.90 kbit/s
1
1792
13.95 kbit/s
0
0
16
1.5625 Mbit/s
0
1
32
781.25 kbit/s
0
1
0
64
390.63 kbit/s
0
1
1
128
195.31 kbit/s
1
1
0
0
256
97.66 kbit/s
1
1
0
1
512
48.83 kbit/s
1
1
1
1
0
1024
24.41 kbit/s
1
1
1
1
1
2048
12.21 kbit/s
SPPR2
SPPR1
SPPR0
SPR2
SPR1
SPR0
1
1
0
1
1
1
1
0
1
1
1
1
1
0
1
1
1
0
1
1
1
1
1
1
1
1
1
1
1
1
15.3.2.4
SPI Status Register (SPISR)
Module Base +0x0003
R
7
6
5
4
3
2
1
0
SPIF
0
SPTEF
MODF
0
0
0
0
0
0
1
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 15-6. SPI Status Register (SPISR)
Read: Anytime
Write: Has no effect
Table 15-8. SPISR Field Descriptions
Field
Description
7
SPIF
SPIF Interrupt Flag — This bit is set after received data has been transferred into the SPI data register. For
information about clearing SPIF Flag, please refer to Table 15-9.
0 Transfer not yet complete.
1 New data copied to SPIDR.
5
SPTEF
SPI Transmit Empty Interrupt Flag — If set, this bit indicates that the transmit data register is empty. For
information about clearing this bit and placing data into the transmit data register, please refer to Table 15-10.
0 SPI data register not empty.
1 SPI data register empty.
4
MODF
Mode Fault Flag — This bit is set if the SS input becomes low while the SPI is configured as a master and mode
fault detection is enabled, MODFEN bit of SPICR2 register is set. Refer to MODFEN bit description in
Section 15.3.2.2, “SPI Control Register 2 (SPICR2)”. The flag is cleared automatically by a read of the SPI status
register (with MODF set) followed by a write to the SPI control register 1.
0 Mode fault has not occurred.
1 Mode fault has occurred.
S12XS Family Reference Manual, Rev. 1.10
444
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
Table 15-9. SPIF Interrupt Flag Clearing Sequence
XFRW Bit
SPIF Interrupt Flag Clearing Sequence
0
Read SPISR with SPIF == 1
1
Read SPISR with SPIF == 1
then
Read SPIDRL
Byte Read SPIDRL 1
or
then
Byte Read SPIDRH 2
Byte Read SPIDRL
or
Word Read (SPIDRH:SPIDRL)
1
2
Data in SPIDRH is lost in this case.
SPIDRH can be read repeatedly without any effect on SPIF. SPIF Flag is cleared only by the read
of SPIDRL after reading SPISR with SPIF == 1.
Table 15-10. SPTEF Interrupt Flag Clearing Sequence
XFRW Bit
SPTEF Interrupt Flag Clearing Sequence
0
Read SPISR with SPTEF == 1 then
1
Read SPISR with SPTEF == 1
Write to SPIDRL 1
Byte Write to SPIDRL 12
or
then Byte Write to SPIDRH 13 Byte Write to SPIDRL 1
or
Word Write to (SPIDRH:SPIDRL) 1
1 Any write to SPIDRH or SPIDRL with SPTEF == 0 is effectively ignored.
2 Data in SPIDRH is undefined in this case.
3 SPIDRH can be written repeatedly without any effect on SPTEF. SPTEF Flag is cleared only by
writing to SPIDRL after reading SPISR with SPTEF == 1.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
445
Serial Peripheral Interface (S12SPIV5)
15.3.2.5
SPI Data Register (SPIDR = SPIDRH:SPIDRL)
Module Base +0x0004
7
6
5
4
3
2
1
0
R
R15
R14
R13
R12
R11
R10
R9
R8
W
T15
T14
T13
T12
T11
T10
T9
T8
0
0
0
0
0
0
0
0
Reset
Figure 15-7. SPI Data Register High (SPIDRH)
Module Base +0x0005
7
6
5
4
3
2
1
0
R
R7
R6
R5
R4
R3
R2
R1
R0
W
T7
T6
T5
T4
T3
T2
T1
T0
0
0
0
0
0
0
0
0
Reset
Figure 15-8. SPI Data Register Low (SPIDRL)
Read: Anytime; read data only valid when SPIF is set
Write: Anytime
The SPI data register is both the input and output register for SPI data. A write to this register
allows data to be queued and transmitted. For an SPI configured as a master, queued data is
transmitted immediately after the previous transmission has completed. The SPI transmitter empty
flag SPTEF in the SPISR register indicates when the SPI data register is ready to accept new data.
Received data in the SPIDR is valid when SPIF is set.
If SPIF is cleared and data has been received, the received data is transferred from the receive shift
register to the SPIDR and SPIF is set.
If SPIF is set and not serviced, and a second data value has been received, the second received data
is kept as valid data in the receive shift register until the start of another transmission. The data in
the SPIDR does not change.
If SPIF is set and valid data is in the receive shift register, and SPIF is serviced before the start of
a third transmission, the data in the receive shift register is transferred into the SPIDR and SPIF
remains set (see Figure 15-9).
If SPIF is set and valid data is in the receive shift register, and SPIF is serviced after the start of a
third transmission, the data in the receive shift register has become invalid and is not transferred
into the SPIDR (see Figure 15-10).
S12XS Family Reference Manual, Rev. 1.10
446
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
Data A Received
Data B Received
Data C Received
SPIF Serviced
Receive Shift Register
Data B
Data A
Data C
SPIF
SPI Data Register
Data B
Data A
= Unspecified
Data C
= Reception in progress
Figure 15-9. Reception with SPIF serviced in Time
Data A Received
Data B Received
Data C Received
Data B Lost
SPIF Serviced
Receive Shift Register
Data B
Data A
Data C
SPIF
SPI Data Register
Data A
= Unspecified
Data C
= Reception in progress
Figure 15-10. Reception with SPIF serviced too late
15.4
Functional Description
The SPI module allows a duplex, synchronous, serial communication between the MCU and peripheral
devices. Software can poll the SPI status flags or SPI operation can be interrupt driven.
The SPI system is enabled by setting the SPI enable (SPE) bit in SPI control register 1. While SPE is set,
the four associated SPI port pins are dedicated to the SPI function as:
• Slave select (SS)
• Serial clock (SCK)
• Master out/slave in (MOSI)
• Master in/slave out (MISO)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
447
Serial Peripheral Interface (S12SPIV5)
The main element of the SPI system is the SPI data register. The n-bit1 data register in the master and the
n-bit1 data register in the slave are linked by the MOSI and MISO pins to form a distributed 2n-bit1
register. When a data transfer operation is performed, this 2n-bit1 register is serially shifted n1 bit positions
by the S-clock from the master, so data is exchanged between the master and the slave. Data written to the
master SPI data register becomes the output data for the slave, and data read from the master SPI data
register after a transfer operation is the input data from the slave.
A read of SPISR with SPTEF = 1 followed by a write to SPIDR puts data into the transmit data register.
When a transfer is complete and SPIF is cleared, received data is moved into the receive data register. This
data register acts as the SPI receive data register for reads and as the SPI transmit data register for writes.
A common SPI data register address is shared for reading data from the read data buffer and for writing
data to the transmit data register.
The clock phase control bit (CPHA) and a clock polarity control bit (CPOL) in the SPI control register 1
(SPICR1) select one of four possible clock formats to be used by the SPI system. The CPOL bit simply
selects a non-inverted or inverted clock. The CPHA bit is used to accommodate two fundamentally
different protocols by sampling data on odd numbered SCK edges or on even numbered SCK edges (see
Section 15.4.3, “Transmission Formats”).
The SPI can be configured to operate as a master or as a slave. When the MSTR bit in SPI control register1
is set, master mode is selected, when the MSTR bit is clear, slave mode is selected.
NOTE
A change of CPOL or MSTR bit while there is a received byte pending in
the receive shift register will destroy the received byte and must be avoided.
15.4.1
Master Mode
The SPI operates in master mode when the MSTR bit is set. Only a master SPI module can initiate
transmissions. A transmission begins by writing to the master SPI data register. If the shift register is
empty, data immediately transfers to the shift register. Data begins shifting out on the MOSI pin under the
control of the serial clock.
• Serial clock
The SPR2, SPR1, and SPR0 baud rate selection bits, in conjunction with the SPPR2, SPPR1, and
SPPR0 baud rate preselection bits in the SPI baud rate register, control the baud rate generator and
determine the speed of the transmission. The SCK pin is the SPI clock output. Through the SCK
pin, the baud rate generator of the master controls the shift register of the slave peripheral.
• MOSI, MISO pin
In master mode, the function of the serial data output pin (MOSI) and the serial data input pin
(MISO) is determined by the SPC0 and BIDIROE control bits.
• SS pin
If MODFEN and SSOE are set, the SS pin is configured as slave select output. The SS output
becomes low during each transmission and is high when the SPI is in idle state.
If MODFEN is set and SSOE is cleared, the SS pin is configured as input for detecting mode fault
error. If the SS input becomes low this indicates a mode fault error where another master tries to
1.
n depends on the selected transfer width, please refer to Section 15.3.2.2, “SPI Control Register 2 (SPICR2)
S12XS Family Reference Manual, Rev. 1.10
448
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
drive the MOSI and SCK lines. In this case, the SPI immediately switches to slave mode, by
clearing the MSTR bit and also disables the slave output buffer MISO (or SISO in bidirectional
mode). So the result is that all outputs are disabled and SCK, MOSI, and MISO are inputs. If a
transmission is in progress when the mode fault occurs, the transmission is aborted and the SPI is
forced into idle state.
This mode fault error also sets the mode fault (MODF) flag in the SPI status register (SPISR). If
the SPI interrupt enable bit (SPIE) is set when the MODF flag becomes set, then an SPI interrupt
sequence is also requested.
When a write to the SPI data register in the master occurs, there is a half SCK-cycle delay. After
the delay, SCK is started within the master. The rest of the transfer operation differs slightly,
depending on the clock format specified by the SPI clock phase bit, CPHA, in SPI control register 1
(see Section 15.4.3, “Transmission Formats”).
NOTE
A change of the bits CPOL, CPHA, SSOE, LSBFE, XFRW, MODFEN,
SPC0, or BIDIROE with SPC0 set, SPPR2-SPPR0 and SPR2-SPR0 in
master mode will abort a transmission in progress and force the SPI into idle
state. The remote slave cannot detect this, therefore the master must ensure
that the remote slave is returned to idle state.
15.4.2
Slave Mode
The SPI operates in slave mode when the MSTR bit in SPI control register 1 is clear.
• Serial clock
In slave mode, SCK is the SPI clock input from the master.
• MISO, MOSI pin
In slave mode, the function of the serial data output pin (MISO) and serial data input pin (MOSI)
is determined by the SPC0 bit and BIDIROE bit in SPI control register 2.
• SS pin
The SS pin is the slave select input. Before a data transmission occurs, the SS pin of the slave SPI
must be low. SS must remain low until the transmission is complete. If SS goes high, the SPI is
forced into idle state.
The SS input also controls the serial data output pin, if SS is high (not selected), the serial data
output pin is high impedance, and, if SS is low, the first bit in the SPI data register is driven out of
the serial data output pin. Also, if the slave is not selected (SS is high), then the SCK input is
ignored and no internal shifting of the SPI shift register occurs.
Although the SPI is capable of duplex operation, some SPI peripherals are capable of only
receiving SPI data in a slave mode. For these simpler devices, there is no serial data out pin.
NOTE
When peripherals with duplex capability are used, take care not to
simultaneously enable two receivers whose serial outputs drive the same
system slave’s serial data output line.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
449
Serial Peripheral Interface (S12SPIV5)
As long as no more than one slave device drives the system slave’s serial data output line, it is possible for
several slaves to receive the same transmission from a master, although the master would not receive return
information from all of the receiving slaves.
If the CPHA bit in SPI control register 1 is clear, odd numbered edges on the SCK input cause the data at
the serial data input pin to be latched. Even numbered edges cause the value previously latched from the
serial data input pin to shift into the LSB or MSB of the SPI shift register, depending on the LSBFE bit.
If the CPHA bit is set, even numbered edges on the SCK input cause the data at the serial data input pin to
be latched. Odd numbered edges cause the value previously latched from the serial data input pin to shift
into the LSB or MSB of the SPI shift register, depending on the LSBFE bit.
When CPHA is set, the first edge is used to get the first data bit onto the serial data output pin. When CPHA
is clear and the SS input is low (slave selected), the first bit of the SPI data is driven out of the serial data
output pin. After the nth1 shift, the transfer is considered complete and the received data is transferred into
the SPI data register. To indicate transfer is complete, the SPIF flag in the SPI status register is set.
NOTE
A change of the bits CPOL, CPHA, SSOE, LSBFE, MODFEN, SPC0, or
BIDIROE with SPC0 set in slave mode will corrupt a transmission in
progress and must be avoided.
15.4.3
Transmission Formats
During an SPI transmission, data is transmitted (shifted out serially) and received (shifted in serially)
simultaneously. The serial clock (SCK) synchronizes shifting and sampling of the information on the two
serial data lines. A slave select line allows selection of an individual slave SPI device; slave devices that
are not selected do not interfere with SPI bus activities. Optionally, on a master SPI device, the slave select
line can be used to indicate multiple-master bus contention.
MASTER SPI
SHIFT REGISTER
BAUD RATE
GENERATOR
SLAVE SPI
MISO
MISO
MOSI
MOSI
SCK
SCK
SS
VDD
SHIFT REGISTER
SS
Figure 15-11. Master/Slave Transfer Block Diagram
15.4.3.1
Clock Phase and Polarity Controls
Using two bits in the SPI control register 1, software selects one of four combinations of serial clock phase
and polarity.
1.
n depends on the selected transfer width, please refer to Section 15.3.2.2, “SPI Control Register 2 (SPICR2)
S12XS Family Reference Manual, Rev. 1.10
450
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
The CPOL clock polarity control bit specifies an active high or low clock and has no significant effect on
the transmission format.
The CPHA clock phase control bit selects one of two fundamentally different transmission formats.
Clock phase and polarity should be identical for the master SPI device and the communicating slave
device. In some cases, the phase and polarity are changed between transmissions to allow a master device
to communicate with peripheral slaves having different requirements.
15.4.3.2
CPHA = 0 Transfer Format
The first edge on the SCK line is used to clock the first data bit of the slave into the master and the first
data bit of the master into the slave. In some peripherals, the first bit of the slave’s data is available at the
slave’s data out pin as soon as the slave is selected. In this format, the first SCK edge is issued a half cycle
after SS has become low.
A half SCK cycle later, the second edge appears on the SCK line. When this second edge occurs, the value
previously latched from the serial data input pin is shifted into the LSB or MSB of the shift register,
depending on LSBFE bit.
After this second edge, the next bit of the SPI master data is transmitted out of the serial data output pin of
the master to the serial input pin on the slave. This process continues for a total of 16 edges on the SCK
line, with data being latched on odd numbered edges and shifted on even numbered edges.
Data reception is double buffered. Data is shifted serially into the SPI shift register during the transfer and
is transferred to the parallel SPI data register after the last bit is shifted in.
After 2n1 (last) SCK edges:
• Data that was previously in the master SPI data register should now be in the slave data register and
the data that was in the slave data register should be in the master.
• The SPIF flag in the SPI status register is set, indicating that the transfer is complete.
Figure 15-12 is a timing diagram of an SPI transfer where CPHA = 0. SCK waveforms are shown for
CPOL = 0 and CPOL = 1. The diagram may be interpreted as a master or slave timing diagram because
the SCK, MISO, and MOSI pins are connected directly between the master and the slave. The MISO signal
is the output from the slave and the MOSI signal is the output from the master. The SS pin of the master
must be either high or reconfigured as a general-purpose output not affecting the SPI.
1.
n depends on the selected transfer width, please refer to Section 15.3.2.2, “SPI Control Register 2 (SPICR2)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
451
Serial Peripheral Interface (S12SPIV5)
End of Idle State
Begin
1
SCK Edge Number
2
3
4
5
6
7
8
Begin of Idle State
End
Transfer
9
10
11
12
13 14
15
16
Bit 1
Bit 6
LSB Minimum 1/2 SCK
for tT, tl, tL
MSB
SCK (CPOL = 0)
SCK (CPOL = 1)
If next transfer begins here
SAMPLE I
MOSI/MISO
CHANGE O
MOSI pin
CHANGE O
MISO pin
SEL SS (O)
Master only
SEL SS (I)
tT
tL
MSB first (LSBFE = 0): MSB
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
LSB first (LSBFE = 1): LSB
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
tL = Minimum leading time before the first SCK edge
tT = Minimum trailing time after the last SCK edge
tI = Minimum idling time between transfers (minimum SS high time)
tL, tT, and tI are guaranteed for the master mode and required for the slave mode.
tI
tL
Figure 15-12. SPI Clock Format 0 (CPHA = 0), with 8-bit Transfer Width selected (XFRW = 0)
S12XS Family Reference Manual, Rev. 1.10
452
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
End of Idle State
SCK Edge Number
Begin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Begin of Idle State
End
Transfer
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
SCK (CPOL = 0)
SCK (CPOL = 1)
If next transfer begins here
SAMPLE I
MOSI/MISO
CHANGE O
MOSI pin
CHANGE O
MISO pin
SEL SS (O)
Master only
SEL SS (I)
MSB first (LSBFE = 0)
LSB first (LSBFE = 1)
tL
tT tI tL
MSB Bit 14Bit 13Bit 12Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 LSB
Minimum 1/2 SCK
LSB Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 Bit 9 Bit 10Bit 11Bit 12Bit 13Bit 14 MSB
for tT, tl, tL
tL = Minimum leading time before the first SCK edge
tT = Minimum trailing time after the last SCK edge
tI = Minimum idling time between transfers (minimum SS high time)
tL, tT, and tI are guaranteed for the master mode and required for the slave mode.
Figure 15-13. SPI Clock Format 0 (CPHA = 0), with 16-Bit Transfer Width selected (XFRW = 1)
In slave mode, if the SS line is not deasserted between the successive transmissions then the content of the
SPI data register is not transmitted; instead the last received data is transmitted. If the SS line is deasserted
for at least minimum idle time (half SCK cycle) between successive transmissions, then the content of the
SPI data register is transmitted.
In master mode, with slave select output enabled the SS line is always deasserted and reasserted between
successive transfers for at least minimum idle time.
15.4.3.3
CPHA = 1 Transfer Format
Some peripherals require the first SCK edge before the first data bit becomes available at the data out pin,
the second edge clocks data into the system. In this format, the first SCK edge is issued by setting the
CPHA bit at the beginning of the n1-cycle transfer operation.
The first edge of SCK occurs immediately after the half SCK clock cycle synchronization delay. This first
edge commands the slave to transfer its first data bit to the serial data input pin of the master.
A half SCK cycle later, the second edge appears on the SCK pin. This is the latching edge for both the
master and slave.
1.
n depends on the selected transfer width, please refer to Section 15.3.2.2, “SPI Control Register 2 (SPICR2)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
453
Serial Peripheral Interface (S12SPIV5)
When the third edge occurs, the value previously latched from the serial data input pin is shifted into the
LSB or MSB of the SPI shift register, depending on LSBFE bit. After this edge, the next bit of the master
data is coupled out of the serial data output pin of the master to the serial input pin on the slave.
This process continues for a total of n1 edges on the SCK line with data being latched on even numbered
edges and shifting taking place on odd numbered edges.
Data reception is double buffered, data is serially shifted into the SPI shift register during the transfer and
is transferred to the parallel SPI data register after the last bit is shifted in.
After 2n1 SCK edges:
• Data that was previously in the SPI data register of the master is now in the data register of the
slave, and data that was in the data register of the slave is in the master.
• The SPIF flag bit in SPISR is set indicating that the transfer is complete.
Figure 15-14 shows two clocking variations for CPHA = 1. The diagram may be interpreted as a master or
slave timing diagram because the SCK, MISO, and MOSI pins are connected directly between the master
and the slave. The MISO signal is the output from the slave, and the MOSI signal is the output from the
master. The SS line is the slave select input to the slave. The SS pin of the master must be either high or
reconfigured as a general-purpose output not affecting the SPI.
End of Idle State
Begin
SCK Edge Number
1
2
3
4
End
Transfer
5
6
7
8
9
10
11
12
13 14
Begin of Idle State
15
16
SCK (CPOL = 0)
SCK (CPOL = 1)
If next transfer begins here
SAMPLE I
MOSI/MISO
CHANGE O
MOSI pin
CHANGE O
MISO pin
SEL SS (O)
Master only
SEL SS (I)
tT
tL
tI
tL
MSB first (LSBFE = 0):
LSB first (LSBFE = 1):
MSB
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
LSB Minimum 1/2 SCK
for tT, tl, tL
LSB
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
MSB
tL = Minimum leading time before the first SCK edge, not required for back-to-back transfers
tT = Minimum trailing time after the last SCK edge
tI = Minimum idling time between transfers (minimum SS high time), not required for back-to-back transfers
Figure 15-14. SPI Clock Format 1 (CPHA = 1), with 8-Bit Transfer Width selected (XFRW = 0)
S12XS Family Reference Manual, Rev. 1.10
454
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
End of Idle State
SCK Edge Number
Begin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Begin of Idle State
End
Transfer
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
SCK (CPOL = 0)
SCK (CPOL = 1)
If next transfer begins here
SAMPLE I
MOSI/MISO
CHANGE O
MOSI pin
CHANGE O
MISO pin
SEL SS (O)
Master only
SEL SS (I)
tT tI tL
Minimum 1/2 SCK
for tT, tl, tL
tL
MSB first (LSBFE = 0)
LSB first (LSBFE = 1)
MSB Bit 14Bit 13Bit 12Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 LSB
LSB Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 Bit 9 Bit 10Bit 11Bit 12Bit 13Bit 14 MSB
tL = Minimum leading time before the first SCK edge, not required for back-to-back transfers
tT = Minimum trailing time after the last SCK edge
tI = Minimum idling time between transfers (minimum SS high time), not required for back-to-back transfers
Figure 15-15. SPI Clock Format 1 (CPHA = 1), with 16-Bit Transfer Width selected (XFRW = 1)
The SS line can remain active low between successive transfers (can be tied low at all times). This format
is sometimes preferred in systems having a single fixed master and a single slave that drive the MISO data
line.
• Back-to-back transfers in master mode
In master mode, if a transmission has completed and new data is available in the SPI data register,
this data is sent out immediately without a trailing and minimum idle time.
The SPI interrupt request flag (SPIF) is common to both the master and slave modes. SPIF gets set one
half SCK cycle after the last SCK edge.
15.4.4
SPI Baud Rate Generation
Baud rate generation consists of a series of divider stages. Six bits in the SPI baud rate register (SPPR2,
SPPR1, SPPR0, SPR2, SPR1, and SPR0) determine the divisor to the SPI module clock which results in
the SPI baud rate.
The SPI clock rate is determined by the product of the value in the baud rate preselection bits
(SPPR2–SPPR0) and the value in the baud rate selection bits (SPR2–SPR0). The module clock divisor
equation is shown in Equation 15-3.
BaudRateDivisor = (SPPR + 1) • 2(SPR + 1)
Eqn. 15-3
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
455
Serial Peripheral Interface (S12SPIV5)
When all bits are clear (the default condition), the SPI module clock is divided by 2. When the selection
bits (SPR2–SPR0) are 001 and the preselection bits (SPPR2–SPPR0) are 000, the module clock divisor
becomes 4. When the selection bits are 010, the module clock divisor becomes 8, etc.
When the preselection bits are 001, the divisor determined by the selection bits is multiplied by 2. When
the preselection bits are 010, the divisor is multiplied by 3, etc. See Table 15-7 for baud rate calculations
for all bit conditions, based on a 25 MHz bus clock. The two sets of selects allows the clock to be divided
by a non-power of two to achieve other baud rates such as divide by 6, divide by 10, etc.
The baud rate generator is activated only when the SPI is in master mode and a serial transfer is taking
place. In the other cases, the divider is disabled to decrease IDD current.
NOTE
For maximum allowed baud rates, please refer to the SPI Electrical
Specification in the Electricals chapter of this data sheet.
15.4.5
15.4.5.1
Special Features
SS Output
The SS output feature automatically drives the SS pin low during transmission to select external devices
and drives it high during idle to deselect external devices. When SS output is selected, the SS output pin
is connected to the SS input pin of the external device.
The SS output is available only in master mode during normal SPI operation by asserting SSOE and
MODFEN bit as shown in Table 15-3.
The mode fault feature is disabled while SS output is enabled.
NOTE
Care must be taken when using the SS output feature in a multimaster
system because the mode fault feature is not available for detecting system
errors between masters.
15.4.5.2
Bidirectional Mode (MOMI or SISO)
The bidirectional mode is selected when the SPC0 bit is set in SPI control register 2 (see Table 15-11). In
this mode, the SPI uses only one serial data pin for the interface with external device(s). The MSTR bit
decides which pin to use. The MOSI pin becomes the serial data I/O (MOMI) pin for the master mode, and
the MISO pin becomes serial data I/O (SISO) pin for the slave mode. The MISO pin in master mode and
MOSI pin in slave mode are not used by the SPI.
S12XS Family Reference Manual, Rev. 1.10
456
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
Table 15-11. Normal Mode and Bidirectional Mode
When SPE = 1
Master Mode MSTR = 1
Serial Out
Normal Mode
SPC0 = 0
MOSI
MOSI
Serial In
SPI
SPI
Serial In
MISO
Serial Out
Bidirectional Mode
SPC0 = 1
Slave Mode MSTR = 0
MOMI
Serial Out
MISO
Serial In
BIDIROE
SPI
BIDIROE
Serial In
SPI
Serial Out
SISO
The direction of each serial I/O pin depends on the BIDIROE bit. If the pin is configured as an output,
serial data from the shift register is driven out on the pin. The same pin is also the serial input to the shift
register.
• The SCK is output for the master mode and input for the slave mode.
• The SS is the input or output for the master mode, and it is always the input for the slave mode.
• The bidirectional mode does not affect SCK and SS functions.
NOTE
In bidirectional master mode, with mode fault enabled, both data pins MISO
and MOSI can be occupied by the SPI, though MOSI is normally used for
transmissions in bidirectional mode and MISO is not used by the SPI. If a
mode fault occurs, the SPI is automatically switched to slave mode. In this
case MISO becomes occupied by the SPI and MOSI is not used. This must
be considered, if the MISO pin is used for another purpose.
15.4.6
Error Conditions
The SPI has one error condition:
• Mode fault error
15.4.6.1
Mode Fault Error
If the SS input becomes low while the SPI is configured as a master, it indicates a system error where more
than one master may be trying to drive the MOSI and SCK lines simultaneously. This condition is not
permitted in normal operation, the MODF bit in the SPI status register is set automatically, provided the
MODFEN bit is set.
In the special case where the SPI is in master mode and MODFEN bit is cleared, the SS pin is not used by
the SPI. In this special case, the mode fault error function is inhibited and MODF remains cleared. In case
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
457
Serial Peripheral Interface (S12SPIV5)
the SPI system is configured as a slave, the SS pin is a dedicated input pin. Mode fault error doesn’t occur
in slave mode.
If a mode fault error occurs, the SPI is switched to slave mode, with the exception that the slave output
buffer is disabled. So SCK, MISO, and MOSI pins are forced to be high impedance inputs to avoid any
possibility of conflict with another output driver. A transmission in progress is aborted and the SPI is
forced into idle state.
If the mode fault error occurs in the bidirectional mode for a SPI system configured in master mode, output
enable of the MOMI (MOSI in bidirectional mode) is cleared if it was set. No mode fault error occurs in
the bidirectional mode for SPI system configured in slave mode.
The mode fault flag is cleared automatically by a read of the SPI status register (with MODF set) followed
by a write to SPI control register 1. If the mode fault flag is cleared, the SPI becomes a normal master or
slave again.
NOTE
If a mode fault error occurs and a received data byte is pending in the receive
shift register, this data byte will be lost.
15.4.7
15.4.7.1
Low Power Mode Options
SPI in Run Mode
In run mode with the SPI system enable (SPE) bit in the SPI control register clear, the SPI system is in a
low-power, disabled state. SPI registers remain accessible, but clocks to the core of this module are
disabled.
15.4.7.2
SPI in Wait Mode
SPI operation in wait mode depends upon the state of the SPISWAI bit in SPI control register 2.
• If SPISWAI is clear, the SPI operates normally when the CPU is in wait mode
• If SPISWAI is set, SPI clock generation ceases and the SPI module enters a power conservation
state when the CPU is in wait mode.
–
If SPISWAI is set and the SPI is configured for master, any transmission and reception in
progress stops at wait mode entry. The transmission and reception resumes when the SPI exits
wait mode.
–
If SPISWAI is set and the SPI is configured as a slave, any transmission and reception in
progress continues if the SCK continues to be driven from the master. This keeps the slave
synchronized to the master and the SCK.
If the master transmits several bytes while the slave is in wait mode, the slave will continue to
send out bytes consistent with the operation mode at the start of wait mode (i.e., if the slave is
currently sending its SPIDR to the master, it will continue to send the same byte. Else if the
slave is currently sending the last received byte from the master, it will continue to send each
previous master byte).
S12XS Family Reference Manual, Rev. 1.10
458
Freescale Semiconductor
Serial Peripheral Interface (S12SPIV5)
NOTE
Care must be taken when expecting data from a master while the slave is in
wait or stop mode. Even though the shift register will continue to operate,
the rest of the SPI is shut down (i.e., a SPIF interrupt will not be generated
until exiting stop or wait mode). Also, the byte from the shift register will
not be copied into the SPIDR register until after the slave SPI has exited wait
or stop mode. In slave mode, a received byte pending in the receive shift
register will be lost when entering wait or stop mode. An SPIF flag and
SPIDR copy is generated only if wait mode is entered or exited during a
tranmission. If the slave enters wait mode in idle mode and exits wait mode
in idle mode, neither a SPIF nor a SPIDR copy will occur.
15.4.7.3
SPI in Stop Mode
Stop mode is dependent on the system. The SPI enters stop mode when the module clock is disabled (held
high or low). If the SPI is in master mode and exchanging data when the CPU enters stop mode, the
transmission is frozen until the CPU exits stop mode. After stop, data to and from the external SPI is
exchanged correctly. In slave mode, the SPI will stay synchronized with the master.
The stop mode is not dependent on the SPISWAI bit.
15.4.7.4
Reset
The reset values of registers and signals are described in Section 15.3, “Memory Map and Register
Definition”, which details the registers and their bit fields.
• If a data transmission occurs in slave mode after reset without a write to SPIDR, it will transmit
garbage, or the data last received from the master before the reset.
• Reading from the SPIDR after reset will always read zeros.
15.4.7.5
Interrupts
The SPI only originates interrupt requests when SPI is enabled (SPE bit in SPICR1 set). The following is
a description of how the SPI makes a request and how the MCU should acknowledge that request. The
interrupt vector offset and interrupt priority are chip dependent.
The interrupt flags MODF, SPIF, and SPTEF are logically ORed to generate an interrupt request.
15.4.7.5.1
MODF
MODF occurs when the master detects an error on the SS pin. The master SPI must be configured for the
MODF feature (see Table 15-3). After MODF is set, the current transfer is aborted and the following bit is
changed:
• MSTR = 0, The master bit in SPICR1 resets.
The MODF interrupt is reflected in the status register MODF flag. Clearing the flag will also clear the
interrupt. This interrupt will stay active while the MODF flag is set. MODF has an automatic clearing
process which is described in Section 15.3.2.4, “SPI Status Register (SPISR)”.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
459
Serial Peripheral Interface (S12SPIV5)
15.4.7.5.2
SPIF
SPIF occurs when new data has been received and copied to the SPI data register. After SPIF is set, it does
not clear until it is serviced. SPIF has an automatic clearing process, which is described in
Section 15.3.2.4, “SPI Status Register (SPISR)”.
15.4.7.5.3
SPTEF
SPTEF occurs when the SPI data register is ready to accept new data. After SPTEF is set, it does not clear
until it is serviced. SPTEF has an automatic clearing process, which is described in Section 15.3.2.4, “SPI
Status Register (SPISR)”.
S12XS Family Reference Manual, Rev. 1.10
460
Freescale Semiconductor
Chapter 16
Timer Module (TIM16B8CV2)
Table 16-1. Revision History
Revision
Number
Revision Date
Sections Affected
V02.05
9 Jul 2009
16.3.2.12/16-477
16.3.2.13/16-477
16.3.2.15/16-479
16.3.2.16/16-480
16.3.2.19/16-482
16.4.2/16-485
16.4.3/16-485
- Revised flag clearing procedure, whereby TEN or PAEN bit must be set
when clearing flags.
- Add fomula to describe prescaler
V02.06
26 Aug 2009
16.1.2/16-462
16.3.2.15/16-479
16.3.2.2/16-468
16.3.2.3/16-469
16.3.2.4/16-470
16.4.3/16-485
- Correct typo: TSCR ->TSCR1
- Correct reference: Figure 1-25 -> Figure 1-31
- Add description, “a counter overflow when TTOV[7] is set”, to be the
condition of channel 7 override event.
- Phrase the description of OC7M to make it more explicit
V02.07
04 May 2010
16.3.2.8/16-473
16.3.2.11/16-476
16.4.3/16-485
- Add Table 16-10
- in TCRE bit description part,add Note
- Add Figure 16-31
16.1
Description of Changes
Introduction
The basic timer consists of a 16-bit, software-programmable counter driven by a enhanced programmable
prescaler.
This timer can be used for many purposes, including input waveform measurements while simultaneously
generating an output waveform. Pulse widths can vary from microseconds to many seconds.
This timer contains 8 complete input capture/output compare channels and one pulse accumulator. The
input capture function is used to detect a selected transition edge and record the time. The output compare
function is used for generating output signals or for timer software delays. The 16-bit pulse accumulator
is used to operate as a simple event counter or a gated time accumulator. The pulse accumulator shares
timer channel 7 when in event mode.
A full access for the counter registers or the input capture/output compare registers should take place in
one clock cycle. Accessing high byte and low byte separately for all of these registers may not yield the
same result as accessing them in one word.
16.1.1
Features
The TIM16B8CV2 includes these distinctive features:
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
461
Timer Module (TIM16B8CV2)
•
•
•
•
Eight input capture/output compare channels.
Clock prescaling.
16-bit counter.
16-bit pulse accumulator.
16.1.2
Modes of Operation
Stop:
Timer is off because clocks are stopped.
Freeze:
Timer counter keep on running, unless TSFRZ in TSCR1 (0x0006) is set to 1.
Wait:
Counters keep on running, unless TSWAI in TSCR1 (0x0006) is set to 1.
Normal:
Timer counter keep on running, unless TEN in TSCR1 (0x0006) is cleared to 0.
S12XS Family Reference Manual, Rev. 1.10
462
Freescale Semiconductor
Timer Module (TIM16B8CV2)
16.1.3
Block Diagrams
Bus clock
Prescaler
16-bit Counter
Channel 0
Input capture
Output compare
Channel 1
Input capture
Output compare
Channel 2
Input capture
Output compare
Timer overflow
interrupt
Timer channel 0
interrupt
Channel 3
Input capture
Output compare
Registers
Channel 4
Input capture
Output compare
Channel 5
Input capture
Output compare
Timer channel 7
interrupt
PA overflow
interrupt
PA input
interrupt
Channel 6
Input capture
Output compare
16-bit
Pulse accumulator
Channel 7
Input capture
Output compare
IOC0
IOC1
IOC2
IOC3
IOC4
IOC5
IOC6
IOC7
Figure 16-1. TIM16B8CV2 Block Diagram
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
463
Timer Module (TIM16B8CV2)
TIMCLK (Timer clock)
CLK1
CLK0
Intermodule Bus
Clock select
(PAMOD)
Edge detector
PT7
PACLK
PACLK / 256
PACLK / 65536
Prescaled clock
(PCLK)
4:1 MUX
Interrupt
PACNT
MUX
Divide by 64
M clock
Figure 16-2. 16-Bit Pulse Accumulator Block Diagram
16-bit Main Timer
PTn
Edge detector
Set CnF Interrupt
TCn Input Capture Reg.
Figure 16-3. Interrupt Flag Setting
S12XS Family Reference Manual, Rev. 1.10
464
Freescale Semiconductor
Timer Module (TIM16B8CV2)
PULSE
ACCUMULATOR
PAD
CHANNEL 7 OUTPUT COMPARE
OCPD
TEN
TIOS7
Figure 16-4. Channel 7 Output Compare/Pulse Accumulator Logic
16.2
External Signal Description
The TIM16B8CV2 module has a total of eight external pins.
16.2.1
IOC7 — Input Capture and Output Compare Channel 7 Pin
This pin serves as input capture or output compare for channel 7. This can also be configured as pulse
accumulator input.
16.2.2
IOC6 — Input Capture and Output Compare Channel 6 Pin
This pin serves as input capture or output compare for channel 6.
16.2.3
IOC5 — Input Capture and Output Compare Channel 5 Pin
This pin serves as input capture or output compare for channel 5.
16.2.4
IOC4 — Input Capture and Output Compare Channel 4 Pin
This pin serves as input capture or output compare for channel 4. Pin
16.2.5
IOC3 — Input Capture and Output Compare Channel 3 Pin
This pin serves as input capture or output compare for channel 3.
16.2.6
IOC2 — Input Capture and Output Compare Channel 2 Pin
This pin serves as input capture or output compare for channel 2.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
465
Timer Module (TIM16B8CV2)
16.2.7
IOC1 — Input Capture and Output Compare Channel 1 Pin
This pin serves as input capture or output compare for channel 1.
16.2.8
IOC0 — Input Capture and Output Compare Channel 0 Pin
This pin serves as input capture or output compare for channel 0.
NOTE
For the description of interrupts see Section 16.6, “Interrupts”.
16.3
Memory Map and Register Definition
This section provides a detailed description of all memory and registers.
16.3.1
Module Memory Map
The memory map for the TIM16B8CV2 module is given below in Figure 16-5. The address listed for each
register is the address offset. The total address for each register is the sum of the base address for the
TIM16B8CV2 module and the address offset for each register.
16.3.2
Register Descriptions
This section consists of register descriptions in address order. Each description includes a standard
register diagram with an associated figure number. Details of register bit and field function follow the
register diagrams, in bit order.
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
0x0000
TIOS
R
W
IOS7
IOS6
IOS5
IOS4
IOS3
IOS2
IOS1
IOS0
0x0001
CFORC
R
W
0
FOC7
0
FOC6
0
FOC5
0
FOC4
0
FOC3
0
FOC2
0
FOC1
0
FOC0
0x0002
OC7M
R
W
OC7M7
OC7M6
OC7M5
OC7M4
OC7M3
OC7M2
OC7M1
OC7M0
0x0003
OC7D
R
W
OC7D7
OC7D6
OC7D5
OC7D4
OC7D3
OC7D2
OC7D1
OC7D0
0x0004
TCNTH
R
W
TCNT15
TCNT14
TCNT13
TCNT12
TCNT11
TCNT10
TCNT9
TCNT8
0x0005
TCNTL
R
W
TCNT7
TCNT6
TCNT5
TCNT4
TCNT3
TCNT2
TCNT1
TCNT0
= Unimplemented or Reserved
Figure 16-5. TIM16B8CV2 Register Summary (Sheet 1 of 3)
S12XS Family Reference Manual, Rev. 1.10
466
Freescale Semiconductor
Timer Module (TIM16B8CV2)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0x0006
TSCR1
R
W
TEN
TSWAI
TSFRZ
TFFCA
PRNT
0x0007
TTOV
R
W
TOV7
TOV6
TOV5
TOV4
TOV3
TOV2
TOV1
TOV0
0x0008
TCTL1
R
W
OM7
OL7
OM6
OL6
OM5
OL5
OM4
OL4
0x0009
TCTL2
R
W
OM3
OL3
OM2
OL2
OM1
OL1
OM0
OL0
0x000A
TCTL3
R
W
EDG7B
EDG7A
EDG6B
EDG6A
EDG5B
EDG5A
EDG4B
EDG4A
0x000B
TCTL4
R
W
EDG3B
EDG3A
EDG2B
EDG2A
EDG1B
EDG1A
EDG0B
EDG0A
0x000C
TIE
R
W
C7I
C6I
C5I
C4I
C3I
C2I
C1I
C0I
0x000D
TSCR2
R
W
TOI
0
0
0
TCRE
PR2
PR1
PR0
0x000E
TFLG1
R
W
C7F
C6F
C5F
C4F
C3F
C2F
C1F
C0F
0x000F
TFLG2
R
W
TOF
0
0
0
0
0
0
0
R
W
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
R
W
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PAEN
PAMOD
PEDGE
CLK1
CLK0
PAOVI
PAI
0
0
0
0
0
PAOVF
PAIF
0x0010–0x001F
TCxH–TCxL
0x0020
PACTL
R
W
0
0x0021
PAFLG
R
W
0
0x0022
PACNTH
R
PACNT15
W
PACNT14
PACNT13
PACNT12
PACNT11
PACNT10
PACNT9
PACNT8
0x0023
PACNTL
R
W
PACNT6
PACNT5
PACNT4
PACNT3
PACNT2
PACNT1
PACNT0
0x0024–0x002B
Reserved
R
W
PACNT7
= Unimplemented or Reserved
Figure 16-5. TIM16B8CV2 Register Summary (Sheet 2 of 3)
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
467
Timer Module (TIM16B8CV2)
Register
Name
0x002C
OCPD
R
W
0x002D
R
0x002E
PTPSR
R
W
0x002F
Reserved
R
W
Bit 7
6
5
4
3
2
1
Bit 0
OCPD7
OCPD6
OCPD5
OCPD4
OCPD3
OCPD2
OCPD1
OCPD0
PTPS7
PTPS6
PTPS5
PTPS4
PTPS3
PTPS2
PTPS1
PTPS0
= Unimplemented or Reserved
Figure 16-5. TIM16B8CV2 Register Summary (Sheet 3 of 3)
16.3.2.1
Timer Input Capture/Output Compare Select (TIOS)
Module Base + 0x0000
7
6
5
4
3
2
1
0
IOS7
IOS6
IOS5
IOS4
IOS3
IOS2
IOS1
IOS0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-6. Timer Input Capture/Output Compare Select (TIOS)
Read: Anytime
Write: Anytime
Table 16-2. TIOS Field Descriptions
Field
7:0
IOS[7:0]
16.3.2.2
Description
Input Capture or Output Compare Channel Configuration
0 The corresponding channel acts as an input capture.
1 The corresponding channel acts as an output compare.
Timer Compare Force Register (CFORC)
Module Base + 0x0001
7
6
5
4
3
2
1
0
R
0
0
0
0
0
0
0
0
W
FOC7
FOC6
FOC5
FOC4
FOC3
FOC2
FOC1
FOC0
0
0
0
0
0
0
0
0
Reset
Figure 16-7. Timer Compare Force Register (CFORC)
S12XS Family Reference Manual, Rev. 1.10
468
Freescale Semiconductor
Timer Module (TIM16B8CV2)
Read: Anytime but will always return 0x0000 (1 state is transient)
Write: Anytime
Table 16-3. CFORC Field Descriptions
Field
Description
7:0
FOC[7:0]
Force Output Compare Action for Channel 7:0 — A write to this register with the corresponding data bit(s) set
causes the action which is programmed for output compare “x” to occur immediately. The action taken is the
same as if a successful comparison had just taken place with the TCx register except the interrupt flag does not
get set.
Note: A channel 7 event, which can be a counter overflow when TTOV[7] is set or a successful output compare
on channel 7, overrides any channel 6:0 compares. If forced output compare on any channel occurs at the
same time as the successful output compare then forced output compare action will take precedence and
interrupt flag won’t get set.
16.3.2.3
Output Compare 7 Mask Register (OC7M)
Module Base + 0x0002
7
6
5
4
3
2
1
0
OC7M7
OC7M6
OC7M5
OC7M4
OC7M3
OC7M2
OC7M1
OC7M0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-8. Output Compare 7 Mask Register (OC7M)
Read: Anytime
Write: Anytime
Table 16-4. OC7M Field Descriptions
Field
Description
7:0
OC7M[7:0]
Output Compare 7 Mask — A channel 7 event, which can be a counter overflow when TTOV[7] is set or a
successful output compare on channel 7, overrides any channel 6:0 compares. For each OC7M bit that is set,
the output compare action reflects the corresponding OC7D bit.
0 The corresponding OC7Dx bit in the output compare 7 data register will not be transferred to the timer port on
a channel 7 event, even if the corresponding pin is setup for output compare.
1 The corresponding OC7Dx bit in the output compare 7 data register will be transferred to the timer port on a
channel 7 event.
Note: The corresponding channel must also be setup for output compare (IOSx = 1 and OCPDx = 0) for data to
be transferred from the output compare 7 data register to the timer port.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
469
Timer Module (TIM16B8CV2)
16.3.2.4
Output Compare 7 Data Register (OC7D)
Module Base + 0x0003
7
6
5
4
3
2
1
0
OC7D7
OC7D6
OC7D5
OC7D4
OC7D3
OC7D2
OC7D1
OC7D0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-9. Output Compare 7 Data Register (OC7D)
Read: Anytime
Write: Anytime
Table 16-5. OC7D Field Descriptions
Field
Description
7:0
OC7D[7:0]
Output Compare 7 Data — A channel 7 event, which can be a counter overflow when TTOV[7] is set or a
successful output compare on channel 7, can cause bits in the output compare 7 data register to transfer to the
timer port data register depending on the output compare 7 mask register.
16.3.2.5
Timer Count Register (TCNT)
Module Base + 0x0004
15
14
13
12
11
10
9
9
TCNT15
TCNT14
TCNT13
TCNT12
TCNT11
TCNT10
TCNT9
TCNT8
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-10. Timer Count Register High (TCNTH)
Module Base + 0x0005
7
6
5
4
3
2
1
0
TCNT7
TCNT6
TCNT5
TCNT4
TCNT3
TCNT2
TCNT1
TCNT0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-11. Timer Count Register Low (TCNTL)
The 16-bit main timer is an up counter.
A full access for the counter register should take place in one clock cycle. A separate read/write for high
byte and low byte will give a different result than accessing them as a word.
Read: Anytime
S12XS Family Reference Manual, Rev. 1.10
470
Freescale Semiconductor
Timer Module (TIM16B8CV2)
Write: Has no meaning or effect in the normal mode; only writable in special modes (test_mode = 1).
The period of the first count after a write to the TCNT registers may be a different size because the write
is not synchronized with the prescaler clock.
16.3.2.6
Timer System Control Register 1 (TSCR1)
Module Base + 0x0006
7
6
5
4
3
TEN
TSWAI
TSFRZ
TFFCA
PRNT
0
0
0
0
0
R
2
1
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 16-12. Timer System Control Register 1 (TSCR1)
Read: Anytime
Write: Anytime
Table 16-6. TSCR1 Field Descriptions
Field
7
TEN
Description
Timer Enable
0 Disables the main timer, including the counter. Can be used for reducing power consumption.
1 Allows the timer to function normally.
If for any reason the timer is not active, there is no ÷64 clock for the pulse accumulator because the ÷64 is
generated by the timer prescaler.
6
TSWAI
Timer Module Stops While in Wait
0 Allows the timer module to continue running during wait.
1 Disables the timer module when the MCU is in the wait mode. Timer interrupts cannot be used to get the MCU
out of wait.
TSWAI also affects pulse accumulator.
5
TSFRZ
Timer Stops While in Freeze Mode
0 Allows the timer counter to continue running while in freeze mode.
1 Disables the timer counter whenever the MCU is in freeze mode. This is useful for emulation.
TSFRZ does not stop the pulse accumulator.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
471
Timer Module (TIM16B8CV2)
Table 16-6. TSCR1 Field Descriptions (continued)
Field
Description
4
TFFCA
Timer Fast Flag Clear All
0 Allows the timer flag clearing to function normally.
1 For TFLG1(0x000E), a read from an input capture or a write to the output compare channel (0x0010–0x001F)
causes the corresponding channel flag, CnF, to be cleared. For TFLG2 (0x000F), any access to the TCNT
register (0x0004, 0x0005) clears the TOF flag. Any access to the PACNT registers (0x0022, 0x0023) clears
the PAOVF and PAIF flags in the PAFLG register (0x0021). This has the advantage of eliminating software
overhead in a separate clear sequence. Extra care is required to avoid accidental flag clearing due to
unintended accesses.
3
PRNT
Precision Timer
0 Enables legacy timer. PR0, PR1, and PR2 bits of the TSCR2 register are used for timer counter prescaler
selection.
1 Enables precision timer. All bits of the PTPSR register are used for Precision Timer Prescaler Selection, and
all bits.
This bit is writable only once out of reset.
16.3.2.7
Timer Toggle On Overflow Register 1 (TTOV)
Module Base + 0x0007
7
6
5
4
3
2
1
0
TOV7
TOV6
TOV5
TOV4
TOV3
TOV2
TOV1
TOV0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-13. Timer Toggle On Overflow Register 1 (TTOV)
Read: Anytime
Write: Anytime
Table 16-7. TTOV Field Descriptions
Field
Description
7:0
TOV[7:0]
Toggle On Overflow Bits — TOVx toggles output compare pin on overflow. This feature only takes effect when
in output compare mode. When set, it takes precedence over forced output compare but not channel 7 override
events.
0 Toggle output compare pin on overflow feature disabled.
1 Toggle output compare pin on overflow feature enabled.
S12XS Family Reference Manual, Rev. 1.10
472
Freescale Semiconductor
Timer Module (TIM16B8CV2)
16.3.2.8
Timer Control Register 1/Timer Control Register 2 (TCTL1/TCTL2)
Module Base + 0x0008
7
6
5
4
3
2
1
0
OM7
OL7
OM6
OL6
OM5
OL5
OM4
OL4
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-14. Timer Control Register 1 (TCTL1)
Module Base + 0x0009
7
6
5
4
3
2
1
0
OM3
OL3
OM2
OL2
OM1
OL1
OM0
OL0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-15. Timer Control Register 2 (TCTL2)
Read: Anytime
Write: Anytime
Table 16-8. TCTL1/TCTL2 Field Descriptions
Field
Description
7:0
OMx
Output Mode — These eight pairs of control bits are encoded to specify the output action to be taken as a result
of a successful OCx compare. When either OMx or OLx is 1, the pin associated with OCx becomes an output
tied to OCx.
Note: To enable output action by OMx bits on timer port, the corresponding bit in OC7M should be cleared. For
an output line to be driven by an OCx the OCPDx must be cleared.
7:0
OLx
Output Level — These eight pairs of control bits are encoded to specify the output action to be taken as a result
of a successful OCx compare. When either OMx or OLx is 1, the pin associated with OCx becomes an output
tied to OCx.
Note: To enable output action by OLx bits on timer port, the corresponding bit in OC7M should be cleared. For
an output line to be driven by an OCx the OCPDx must be cleared.
Table 16-9. Compare Result Output Action
OMx
OLx
Action
0
0
No output compare
action on the timer output signal
0
1
Toggle OCx output line
1
0
Clear OCx output line to zero
1
1
Set OCx output line to one
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
473
Timer Module (TIM16B8CV2)
To operate the 16-bit pulse accumulator independently of input capture or output compare 7 and 0
respectively the user must set the corresponding bits IOSx = 1, OMx = 0 and OLx = 0. OC7M7 in the
OC7M register must also be cleared.
To enable output action using the OM7 and OL7 bits on the timer port,the corresponding bit OC7M7 in
the OC7M register must also be cleared. The settings for these bits can be seen in Table 16-10
Table 16-10. The OC7 and OCx event priority
OC7M7=0
OC7M7=1
OC7Mx=1
TC7=TCx
OC7Mx=0
TC7>TCx
TC7=TCx
OC7Mx=1
TC7>TCx
TC7=TCx
IOCx=OMx/OLx
IOC7=OM7/OL7
IOCx=OC7Dx IOCx=OC7Dx
IOC7=OM7/O +OMx/OLx
L7
IOC7=OM7/O
L7
OC7Mx=0
TC7>TCx
IOCx=OC7Dx IOCx=OC7Dx
IOC7=OC7D7 +OMx/OLx
IOC7=OC7D7
TC7=TCx
TC7>TCx
IOCx=OMx/OLx
IOC7=OC7D7
Note: in Table 16-10, the IOS7 and IOSx should be set to 1
IOSx is the register TIOS bit x,
OC7Mx is the register OC7M bit x,
TCx is timer Input Capture/Output Compare register,
IOCx is channel x,
OMx/OLx is the register TCTL1/TCTL2,
OC7Dx is the register OC7D bit x.
IOCx = OC7Dx+ OMx/OLx, means that both OC7 event and OCx event will change channel x value.
16.3.2.9
Timer Control Register 3/Timer Control Register 4 (TCTL3 and TCTL4)
Module Base + 0x000A
7
6
5
4
3
2
1
0
EDG7B
EDG7A
EDG6B
EDG6A
EDG5B
EDG5A
EDG4B
EDG4A
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-16. Timer Control Register 3 (TCTL3)
Module Base + 0x000B
7
6
5
4
3
2
1
0
EDG3B
EDG3A
EDG2B
EDG2A
EDG1B
EDG1A
EDG0B
EDG0A
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-17. Timer Control Register 4 (TCTL4)
S12XS Family Reference Manual, Rev. 1.10
474
Freescale Semiconductor
Timer Module (TIM16B8CV2)
Read: Anytime
Write: Anytime.
Table 16-11. TCTL3/TCTL4 Field Descriptions
Field
7:0
EDGnB
EDGnA
Description
Input Capture Edge Control — These eight pairs of control bits configure the input capture edge detector
circuits.
Table 16-12. Edge Detector Circuit Configuration
EDGnB
EDGnA
Configuration
0
0
Capture disabled
0
1
Capture on rising edges only
1
0
Capture on falling edges only
1
1
Capture on any edge (rising or falling)
16.3.2.10 Timer Interrupt Enable Register (TIE)
Module Base + 0x000C
7
6
5
4
3
2
1
0
C7I
C6I
C5I
C4I
C3I
C2I
C1I
C0I
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-18. Timer Interrupt Enable Register (TIE)
Read: Anytime
Write: Anytime.
Table 16-13. TIE Field Descriptions
Field
Description
7:0
C7I:C0I
Input Capture/Output Compare “x” Interrupt Enable — The bits in TIE correspond bit-for-bit with the bits in
the TFLG1 status register. If cleared, the corresponding flag is disabled from causing a hardware interrupt. If set,
the corresponding flag is enabled to cause a interrupt.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
475
Timer Module (TIM16B8CV2)
16.3.2.11 Timer System Control Register 2 (TSCR2)
Module Base + 0x000D
7
R
6
5
4
0
0
0
TOI
3
2
1
0
TCRE
PR2
PR1
PR0
0
0
0
0
W
Reset
0
0
0
0
= Unimplemented or Reserved
Figure 16-19. Timer System Control Register 2 (TSCR2)
Read: Anytime
Write: Anytime.
Table 16-14. TSCR2 Field Descriptions
Field
7
TOI
Description
Timer Overflow Interrupt Enable
0 Interrupt inhibited.
1 Hardware interrupt requested when TOF flag set.
3
TCRE
Timer Counter Reset Enable — This bit allows the timer counter to be reset by a successful output compare 7
event. This mode of operation is similar to an up-counting modulus counter.
0 Counter reset inhibited and counter free runs.
1 Counter reset by a successful output compare 7.
Note: If TC7 = 0x0000 and TCRE = 1, TCNT will stay at 0x0000 continuously. If TC7 = 0xFFFF and TCRE = 1,
TOF will never be set when TCNT is reset from 0xFFFF to 0x0000.
Note: TCRE=1 and TC7!=0, the TCNT cycle period will be TC7 x "prescaler counter width" + "1 Bus Clock", for
a more detail explanation please refer to Section 16.4.3, “Output Compare
2
PR[2:0]
Timer Prescaler Select — These three bits select the frequency of the timer prescaler clock derived from the
Bus Clock as shown in Table 16-15.
Table 16-15. Timer Clock Selection
PR2
PR1
PR0
Timer Clock
0
0
0
Bus Clock / 1
0
0
1
Bus Clock / 2
0
1
0
Bus Clock / 4
0
1
1
Bus Clock / 8
1
0
0
Bus Clock / 16
1
0
1
Bus Clock / 32
1
1
0
Bus Clock / 64
1
1
1
Bus Clock / 128
S12XS Family Reference Manual, Rev. 1.10
476
Freescale Semiconductor
Timer Module (TIM16B8CV2)
NOTE
The newly selected prescale factor will not take effect until the next
synchronized edge where all prescale counter stages equal zero.
16.3.2.12 Main Timer Interrupt Flag 1 (TFLG1)
Module Base + 0x000E
7
6
5
4
3
2
1
0
C7F
C6F
C5F
C4F
C3F
C2F
C1F
C0F
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-20. Main Timer Interrupt Flag 1 (TFLG1)
Read: Anytime
Write: Used in the clearing mechanism (set bits cause corresponding bits to be cleared). Writing a zero
will not affect current status of the bit.
Table 16-16. TRLG1 Field Descriptions
Field
Description
7:0
C[7:0]F
Input Capture/Output Compare Channel “x” Flag — These flags are set when an input capture or output
compare event occurs. Clearing requires writing a one to the corresponding flag bit while TEN or PAEN is set to
one.
When TFFCA bit in TSCR register is set, a read from an input capture or a write into an output compare channel
(0x0010–0x001F) will cause the corresponding channel flag CxF to be cleared.
16.3.2.13 Main Timer Interrupt Flag 2 (TFLG2)
Module Base + 0x000F
7
R
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
TOF
W
Reset
0
Unimplemented or Reserved
Figure 16-21. Main Timer Interrupt Flag 2 (TFLG2)
TFLG2 indicates when interrupt conditions have occurred. To clear a bit in the flag register, write the bit
to one while TEN bit of TSCR1 or PAEN bit of PACTL is set to one.
Read: Anytime
Write: Used in clearing mechanism (set bits cause corresponding bits to be cleared).
Any access to TCNT will clear TFLG2 register if the TFFCA bit in TSCR register is set.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
477
Timer Module (TIM16B8CV2)
Table 16-17. TRLG2 Field Descriptions
Field
Description
7
TOF
Timer Overflow Flag — Set when 16-bit free-running timer overflows from 0xFFFF to 0x0000. Clearing this bit
requires writing a one to bit 7 of TFLG2 register while the TEN bit of TSCR1 or PAEN bit of PACTL is set to one
(See also TCRE control bit explanation.)
16.3.2.14 Timer Input Capture/Output Compare Registers High and Low 0–7
(TCxH and TCxL)
0x0018 = TC4H
0x001A = TC5H
0x001C = TC6H
0x001E = TC7H
Module Base + 0x0010 = TC0H
0x0012 = TC1H
0x0014 = TC2H
0x0016 = TC3H
15
14
13
12
11
10
9
0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-22. Timer Input Capture/Output Compare Register x High (TCxH)
0x0019 = TC4L
0x001B = TC5L
0x001D = TC6L
0x001F = TC7L
Module Base + 0x0011 = TC0L
0x0013 = TC1L
0x0015 = TC2L
0x0017 = TC3L
7
6
5
4
3
2
1
0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-23. Timer Input Capture/Output Compare Register x Low (TCxL)
Depending on the TIOS bit for the corresponding channel, these registers are used to latch the value of the
free-running counter when a defined transition is sensed by the corresponding input capture edge detector
or to trigger an output action for output compare.
Read: Anytime
Write: Anytime for output compare function.Writes to these registers have no meaning or effect during
input capture. All timer input capture/output compare registers are reset to 0x0000.
NOTE
Read/Write access in byte mode for high byte should takes place before low
byte otherwise it will give a different result.
S12XS Family Reference Manual, Rev. 1.10
478
Freescale Semiconductor
Timer Module (TIM16B8CV2)
16.3.2.15 16-Bit Pulse Accumulator Control Register (PACTL)
Module Base + 0x0020
7
R
6
5
4
3
2
1
0
PAEN
PAMOD
PEDGE
CLK1
CLK0
PAOVI
PAI
0
0
0
0
0
0
0
0
W
Reset
0
Unimplemented or Reserved
Figure 16-24. 16-Bit Pulse Accumulator Control Register (PACTL)
When PAEN is set, the PACT is enabled.The PACT shares the input pin with IOC7.
Read: Any time
Write: Any time
Table 16-18. PACTL Field Descriptions
Field
6
PAEN
Description
Pulse Accumulator System Enable — PAEN is independent from TEN. With timer disabled, the pulse
accumulator can function unless pulse accumulator is disabled.
0 16-Bit Pulse Accumulator system disabled.
1 Pulse Accumulator system enabled.
5
PAMOD
Pulse Accumulator Mode — This bit is active only when the Pulse Accumulator is enabled (PAEN = 1). See
Table 16-19.
0 Event counter mode.
1 Gated time accumulation mode.
4
PEDGE
Pulse Accumulator Edge Control — This bit is active only when the Pulse Accumulator is enabled (PAEN = 1).
For PAMOD bit = 0 (event counter mode). See Table 16-19.
0 Falling edges on IOC7 pin cause the count to be incremented.
1 Rising edges on IOC7 pin cause the count to be incremented.
For PAMOD bit = 1 (gated time accumulation mode).
0 IOC7 input pin high enables M (bus clock) divided by 64 clock to Pulse Accumulator and the trailing falling
edge on IOC7 sets the PAIF flag.
1 IOC7 input pin low enables M (bus clock) divided by 64 clock to Pulse Accumulator and the trailing rising edge
on IOC7 sets the PAIF flag.
3:2
CLK[1:0]
Clock Select Bits — Refer to Table 16-20.
1
PAOVI
0
PAI
Pulse Accumulator Overflow Interrupt Enable
0 Interrupt inhibited.
1 Interrupt requested if PAOVF is set.
Pulse Accumulator Input Interrupt Enable
0 Interrupt inhibited.
1 Interrupt requested if PAIF is set.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
479
Timer Module (TIM16B8CV2)
Table 16-19. Pin Action
PAMOD
PEDGE
Pin Action
0
0
Falling edge
0
1
Rising edge
1
0
Div. by 64 clock enabled with pin high level
1
1
Div. by 64 clock enabled with pin low level
NOTE
If the timer is not active (TEN = 0 in TSCR), there is no divide-by-64
because the ÷64 clock is generated by the timer prescaler.
Table 16-20. Timer Clock Selection
CLK1
CLK0
Timer Clock
0
0
Use timer prescaler clock as timer counter clock
0
1
Use PACLK as input to timer counter clock
1
0
Use PACLK/256 as timer counter clock frequency
1
1
Use PACLK/65536 as timer counter clock frequency
For the description of PACLK please refer Figure 16-30.
If the pulse accumulator is disabled (PAEN = 0), the prescaler clock from the timer is always used as an
input clock to the timer counter. The change from one selected clock to the other happens immediately
after these bits are written.
16.3.2.16 Pulse Accumulator Flag Register (PAFLG)
Module Base + 0x0021
R
7
6
5
4
3
2
0
0
0
0
0
0
1
0
PAOVF
PAIF
0
0
W
Reset
0
0
0
0
0
0
Unimplemented or Reserved
Figure 16-25. Pulse Accumulator Flag Register (PAFLG)
Read: Anytime
Write: Anytime
When the TFFCA bit in the TSCR register is set, any access to the PACNT register will clear all the flags
in the PAFLG register. Timer module or Pulse Accumulator must stay enabled (TEN=1 or PAEN=1) while
clearing these bits.
S12XS Family Reference Manual, Rev. 1.10
480
Freescale Semiconductor
Timer Module (TIM16B8CV2)
Table 16-21. PAFLG Field Descriptions
Field
Description
1
PAOVF
Pulse Accumulator Overflow Flag — Set when the 16-bit pulse accumulator overflows from 0xFFFF to 0x0000.
Clearing this bit requires writing a one to this bit in the PAFLG register while TEN bit of TSCR1 or PAEN bit of
PACTL register is set to one.
0
PAIF
Pulse Accumulator Input edge Flag — Set when the selected edge is detected at the IOC7 input pin.In event
mode the event edge triggers PAIF and in gated time accumulation mode the trailing edge of the gate signal at
the IOC7 input pin triggers PAIF.
Clearing this bit requires writing a one to this bit in the PAFLG register while TEN bit of TSCR1 or PAEN bit of
PACTL register is set to one. Any access to the PACNT register will clear all the flags in this register when TFFCA
bit in register TSCR(0x0006) is set.
16.3.2.17 Pulse Accumulators Count Registers (PACNT)
Module Base + 0x0022
15
14
13
12
11
10
9
0
PACNT15
PACNT14
PACNT13
PACNT12
PACNT11
PACNT10
PACNT9
PACNT8
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-26. Pulse Accumulator Count Register High (PACNTH)
Module Base + 0x0023
7
6
5
4
3
2
1
0
PACNT7
PACNT6
PACNT5
PACNT4
PACNT3
PACNT2
PACNT1
PACNT0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-27. Pulse Accumulator Count Register Low (PACNTL)
Read: Anytime
Write: Anytime
These registers contain the number of active input edges on its input pin since the last reset.
When PACNT overflows from 0xFFFF to 0x0000, the Interrupt flag PAOVF in PAFLG (0x0021) is set.
Full count register access should take place in one clock cycle. A separate read/write for high byte and low
byte will give a different result than accessing them as a word.
NOTE
Reading the pulse accumulator counter registers immediately after an
active edge on the pulse accumulator input pin may miss the last count
because the input has to be synchronized with the bus clock first.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
481
Timer Module (TIM16B8CV2)
16.3.2.18 Output Compare Pin Disconnect Register(OCPD)
Module Base + 0x002C
7
6
5
4
3
2
1
0
OCPD7
OCPD6
OCPD5
OCPD4
OCPD3
OCPD2
OCPD1
OCPD0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-28. Ouput Compare Pin Disconnect Register (OCPD)
Read: Anytime
Write: Anytime
All bits reset to zero.
Table 16-22. OCPD Field Description
Field
OCPD[7:0}
Description
Output Compare Pin Disconnect Bits
0 Enables the timer channel port. Ouptut Compare action will occur on the channel pin. These bits do not affect
the input capture or pulse accumulator functions
1 Disables the timer channel port. Output Compare action will not occur on the channel pin, but the output
compare flag still become set .
16.3.2.19 Precision Timer Prescaler Select Register (PTPSR)
Module Base + 0x002E
7
6
5
4
3
2
1
0
PTPS7
PTPS6
PTPS5
PTPS4
PTPS3
PTPS2
PTPS1
PTPS0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 16-29. Precision Timer Prescaler Select Register (PTPSR)
Read: Anytime
Write: Anytime
All bits reset to zero.
S12XS Family Reference Manual, Rev. 1.10
482
Freescale Semiconductor
Timer Module (TIM16B8CV2)
Table 16-23. PTPSR Field Descriptions
Field
Description
7:0
PTPS[7:0]
Precision Timer Prescaler Select Bits — These eight bits specify the division rate of the main Timer prescaler.
These are effective only when the PRNT bit of TSCR1 is set to 1. Table 16-24 shows some selection examples
in this case.
The newly selected prescale factor will not take effect until the next synchronized edge where all prescale counter
stages equal zero.
The Prescaler can be calculated as follows depending on logical value of the PTPS[7:0] and PRNT bit:
PRNT = 1 : Prescaler = PTPS[7:0] + 1
Table 16-24. Precision Timer Prescaler Selection Examples when PRNT = 1
PTPS7
PTPS6
PTPS5
PTPS4
PTPS3
PTPS2
PTPS1
PTPS0
Prescale
Factor
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
2
0
0
0
0
0
0
1
0
3
0
0
0
0
0
0
1
1
4
0
0
0
0
0
1
0
0
5
0
0
0
0
0
1
0
1
6
0
0
0
0
0
1
1
0
7
0
0
0
0
0
1
1
1
8
0
0
0
0
1
1
1
1
16
0
0
0
1
1
1
1
1
32
0
0
1
1
1
1
1
1
64
0
1
1
1
1
1
1
1
128
1
1
1
1
1
1
1
1
256
16.4
Functional Description
This section provides a complete functional description of the timer TIM16B8CV2 block. Please refer to
the detailed timer block diagram in Figure 16-30 as necessary.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
483
Timer Module (TIM16B8CV2)
Bus Clock
CLK[1:0]
PR[2:1:0]
channel 7 output
compare
PACLK
PACLK/256
PACLK/65536
MUX
TCRE
PRESCALER
CxI
TCNT(hi):TCNT(lo)
CxF
CLEAR COUNTER
16-BIT COUNTER
TOF
INTERRUPT
LOGIC
TOI
TE
TOF
CHANNEL 0
16-BIT COMPARATOR
OM:OL0
TC0
EDG0A
C0F
C0F
EDGE
DETECT
EDG0B
CH. 0 CAPTURE
IOC0 PIN
LOGIC CH. 0COMPARE
TOV0
IOC0 PIN
IOC0
CHANNEL 1
16-BIT COMPARATOR
OM:OL1
EDGE
DETECT
EDG1B
EDG1A
C1F
C1F
TC1
CH. 1 CAPTURE
IOC1 PIN
LOGIC CH. 1 COMPARE
TOV1
IOC1 PIN
IOC1
CHANNEL2
CHANNEL7
16-BIT COMPARATOR
TC7
OM:OL7
EDG7A
EDGE
DETECT
EDG7B
PAOVF
C7F
C7F
PACNT(hi):PACNT(lo)
TOV7
IOC7
PEDGE
PAE
PACLK/65536
CH.7 CAPTURE
IOC7 PIN PA INPUT
LOGIC CH. 7 COMPARE IOC7 PIN
EDGE
DETECT
16-BIT COUNTER
PACLK
PACLK/256
TEN
INTERRUPT
REQUEST
INTERRUPT
LOGIC
PAIF
DIVIDE-BY-64
PAOVI
PAI
PAOVF
PAIF
Bus Clock
PAOVF
PAOVI
Figure 16-30. Detailed Timer Block Diagram
16.4.1
Prescaler
The prescaler divides the bus clock by 1,2,4,8,16,32,64 or 128. The prescaler select bits, PR[2:0], select
the prescaler divisor. PR[2:0] are in timer system control register 2 (TSCR2).
S12XS Family Reference Manual, Rev. 1.10
484
Freescale Semiconductor
Timer Module (TIM16B8CV2)
The prescaler divides the bus clock by a prescalar value. Prescaler select bits PR[2:0] of in timer system
control register 2 (TSCR2) are set to define a prescalar value that generates a divide by 1, 2, 4, 8, 16, 32,
64 and 128 when the PRNT bit in TSCR1 is disabled.
By enabling the PRNT bit of the TSCR1 register, the performance of the timer can be enhanced. In this
case, it is possible to set additional prescaler settings for the main timer counter in the present timer by
using PTPSR[7:0] bits of PTPSR register.
16.4.2
Input Capture
Clearing the I/O (input/output) select bit, IOSx, configures channel x as an input capture channel. The
input capture function captures the time at which an external event occurs. When an active edge occurs on
the pin of an input capture channel, the timer transfers the value in the timer counter into the timer channel
registers, TCx.
The minimum pulse width for the input capture input is greater than two bus clocks.
An input capture on channel x sets the CxF flag. The CxI bit enables the CxF flag to generate interrupt
requests. Timer module or Pulse Accumulator must stay enabled (TEN bit of TSCR1 or PAEN bit of
PACTL regsiter must be set to one) while clearing CxF (writing one to CxF).
16.4.3
Output Compare
Setting the I/O select bit, IOSx, configures channel x as an output compare channel. The output compare
function can generate a periodic pulse with a programmable polarity, duration, and frequency. When the
timer counter reaches the value in the channel registers of an output compare channel, the timer can set,
clear, or toggle the channel pin if the corresponding OCPDx bit is set to zero. An output compare on
channel x sets the CxF flag. The CxI bit enables the CxF flag to generate interrupt requests. Timer module
or Pulse Accumulator must stay enabled (TEN bit of TSCR1 or PAEN bit of PACTL regsiter must be set
to one) while clearing CxF (writing one to CxF).
The output mode and level bits, OMx and OLx, select set, clear, toggle on output compare. Clearing both
OMx and OLx results in no output compare action on the output compare channel pin.
Setting a force output compare bit, FOCx, causes an output compare on channel x. A forced output
compare does not set the channel flag.
A channel 7 event, which can be a counter overflow when TTOV[7] is set or a successful output compare
on channel 7, overrides output compares on all other output compare channels. The output compare 7 mask
register masks the bits in the output compare 7 data register. The timer counter reset enable bit, TCRE,
enables channel 7 output compares to reset the timer counter. A channel 7 output compare can reset the
timer counter even if the IOC7 pin is being used as the pulse accumulator input.
Writing to the timer port bit of an output compare pin does not affect the pin state. The value written is
stored in an internal latch. When the pin becomes available for general-purpose output, the last value
written to the bit appears at the pin.
When TCRE is set and TC7 is not equal to 0, then TCNT will cycle from 0 to TC7. When TCNT reaches
TC7 value, it will last only one bus cycle then reset to 0.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
485
Timer Module (TIM16B8CV2)
Note: in Figure 16-31,if PR[2:0] is equal to 0, one prescaler counter equal to one bus clock
Figure 16-31. The TCNT cycle diagram under TCRE=1 condition
prescaler
counter
TC7
1 bus
clock
0
1
TC7-1
TC7
0
TC7 event
TC7 event
16.4.3.1
-----
OC Channel Initialization
Internal register whose output drives OCx can be programmed before timer drives OCx. The desired state
can be programmed to this Internal register by writing a one to CFORCx bit with TIOSx, OCPDx and TEN
bits set to one. Setting OCPDx to zero allows Interal register to drive the programmed state to OCx. This
allows a glitch free switch over of port from general purpose I/O to timer output once the OCPDx bit is set
to zero.
16.4.4
Pulse Accumulator
The pulse accumulator (PACNT) is a 16-bit counter that can operate in two modes:
Event counter mode — Counting edges of selected polarity on the pulse accumulator input pin, PAI.
Gated time accumulation mode — Counting pulses from a divide-by-64 clock. The PAMOD bit selects the
mode of operation.
The minimum pulse width for the PAI input is greater than two bus clocks.
16.4.5
Event Counter Mode
Clearing the PAMOD bit configures the PACNT for event counter operation. An active edge on the IOC7
pin increments the pulse accumulator counter. The PEDGE bit selects falling edges or rising edges to
increment the count.
NOTE
The PACNT input and timer channel 7 use the same pin IOC7. To use the
IOC7, disconnect it from the output logic by clearing the channel 7 output
mode and output level bits, OM7 and OL7. Also clear the channel 7 output
compare 7 mask bit, OC7M7.
The Pulse Accumulator counter register reflect the number of active input edges on the PACNT input pin
since the last reset.
The PAOVF bit is set when the accumulator rolls over from 0xFFFF to 0x0000. The pulse accumulator
overflow interrupt enable bit, PAOVI, enables the PAOVF flag to generate interrupt requests.
S12XS Family Reference Manual, Rev. 1.10
486
Freescale Semiconductor
Timer Module (TIM16B8CV2)
NOTE
The pulse accumulator counter can operate in event counter mode even
when the timer enable bit, TEN, is clear.
16.4.6
Gated Time Accumulation Mode
Setting the PAMOD bit configures the pulse accumulator for gated time accumulation operation. An active
level on the PACNT input pin enables a divided-by-64 clock to drive the pulse accumulator. The PEDGE
bit selects low levels or high levels to enable the divided-by-64 clock.
The trailing edge of the active level at the IOC7 pin sets the PAIF. The PAI bit enables the PAIF flag to
generate interrupt requests.
The pulse accumulator counter register reflect the number of pulses from the divided-by-64 clock since the
last reset.
NOTE
The timer prescaler generates the divided-by-64 clock. If the timer is not
active, there is no divided-by-64 clock.
16.5
Resets
The reset state of each individual bit is listed within Section 16.3, “Memory Map and Register Definition”
which details the registers and their bit fields.
16.6
Interrupts
This section describes interrupts originated by the TIM16B8CV2 block. Table 16-25 lists the interrupts
generated by the TIM16B8CV2 to communicate with the MCU.
Table 16-25. TIM16B8CV1 Interrupts
1
Interrupt
Offset1
Vector1
Priority1
Source
Description
C[7:0]F
—
—
—
Timer Channel 7–0
Active high timer channel interrupts 7–0
PAOVI
—
—
—
Pulse Accumulator
Input
Active high pulse accumulator input interrupt
PAOVF
—
—
—
Pulse Accumulator
Overflow
Pulse accumulator overflow interrupt
TOF
—
—
—
Timer Overflow
Timer Overflow interrupt
Chip Dependent.
The TIM16B8CV2 uses a total of 11 interrupt vectors. The interrupt vector offsets and interrupt numbers
are chip dependent.
S12XS Family Reference Manual Rev. 1.10
Freescale Semiconductor
487
Timer Module (TIM16B8CV2)
16.6.1
Channel [7:0] Interrupt (C[7:0]F)
This active high outputs will be asserted by the module to request a timer channel 7 – 0 interrupt to be
serviced by the system controller.
16.6.2
Pulse Accumulator Input Interrupt (PAOVI)
This active high output will be asserted by the module to request a timer pulse accumulator input interrupt
to be serviced by the system controller.
16.6.3
Pulse Accumulator Overflow Interrupt (PAOVF)
This active high output will be asserted by the module to request a timer pulse accumulator overflow
interrupt to be serviced by the system controller.
16.6.4
Timer Overflow Interrupt (TOF)
This active high output will be asserted by the module to request a timer overflow interrupt to be serviced
by the system controller.
S12XS Family Reference Manual, Rev. 1.10
488
Freescale Semiconductor
Chapter 17
Voltage Regulator (S12VREGL3V3V1)
Table 17-1. Revision History Table
Rev. No.
Date
(Item No.) (Submitted By)
Sections
Affected
Substantial Change(s)
V01.02
09 Sep 2005
Updates for API external access and LVR flags.
V01.03
23 Sep 2005
VAE reset value is 1.
V01.04
08 Jun 2007
Added temperature sensor to customer information
17.1
Introduction
Module VREG_3V3 is a tri output voltage regulator that provides two separate 1.84V (typical) supplies
differing in the amount of current that can be sourced and a 2.82V (typical) supply. The regulator input
voltage range is from 3.3V up to 5V (typical).
17.1.1
Features
Module VREG_3V3 includes these distinctive features:
• Three parallel, linear voltage regulators with bandgap reference
• Low-voltage detect (LVD) with low-voltage interrupt (LVI)
• Power-on reset (POR)
• Low-voltage reset (LVR)
• High Temperature Detect (HTD) with High Temperature Interrupt (HTI)
• Autonomous periodical interrupt (API)
17.1.2
Modes of Operation
There are three modes VREG_3V3 can operate in:
1. Full performance mode (FPM) (MCU is not in stop mode)
The regulator is active, providing the nominal supply voltages with full current sourcing capability.
Features LVD (low-voltage detect), LVR (low-voltage reset), and POR (power-on reset) and HTD
(High Temperature Detect) are available. The API is available.
2. Reduced power mode (RPM) (MCU is in stop mode)
The purpose is to reduce power consumption of the device. The output voltage may degrade to a
lower value than in full performance mode, additionally the current sourcing capability is
substantially reduced. Only the POR is available in this mode, LVD, LVR and HTD are disabled.
The API is available.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
489
Voltage Regulator (S12VREGL3V3V1)
3. Shutdown mode
Controlled by VREGEN (see device level specification for connectivity of VREGEN).
This mode is characterized by minimum power consumption. The regulator outputs are in a highimpedance state, only the POR feature is available, LVD, LVR and HTD are disabled. The API
internal RC oscillator clock is not available.
This mode must be used to disable the chip internal regulator VREG_3V3, i.e., to bypass the
VREG_3V3 to use external supplies.
17.1.3
Block Diagram
Figure 17-1 shows the function principle of VREG_3V3 by means of a block diagram. The regulator core
REG consists of three parallel subblocks, REG1, REG2 and REG3, providing three independent output
voltages.
S12XS Family Reference Manual, Rev. 1.10
490
Freescale Semiconductor
Voltage Regulator (S12VREGL3V3V1)
Figure 17-1. VREG_3V3 Block Diagram
VBG
VDDPLL
REG3
VSSPLL
REG
VDDR
VDDA
VDDF
REG2
VSSA
VDD
REG1
VSS
LVD
LVR
LVR
POR
POR
VDDX
C
HTD
VREGEN
CTRL
API
Rate
Select
HTI
LVI
API
API
Bus Clock
LVD: Low Voltage Detect
REG: Regulator Core
LVR: Low Voltage Reset
CTRL: Regulator Control
POR: Power-on Reset
API: Auto. Periodical Interrupt
HTD: High Temperature Detect
PIN
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
491
Voltage Regulator (S12VREGL3V3V1)
17.2
External Signal Description
Due to the nature of VREG_3V3 being a voltage regulator providing the chip internal power supply
voltages, most signals are power supply signals connected to pads.
Table 17-2 shows all signals of VREG_3V3 associated with pins.
Table 17-2. Signal Properties
Name
Function
Reset State
Pull Up
VDDR
Power input (positive supply)
—
—
VDDA
Quiet input (positive supply)
—
—
VSSA
Quiet input (ground)
—
—
VDDX
Power input (positive supply)
—
—
VDD
Primary output (positive supply)
—
—
VSS
Primary output (ground)
—
—
Secondary output (positive supply)
—
—
VDDPLL
Tertiary output (positive supply)
—
—
VSSPLL
Tertiary output (ground)
—
—
Optional Regulator Enable
—
—
VREG Autonomous Periodical
Interrupt output
—
—
VDDF
VREGEN (optional)
VREG_API
(optional)
NOTE
Check device level specification for connectivity of the signals.
17.2.1
VDDR — Regulator Power Input Pins
Signal VDDR is the power input of VREG_3V3. All currents sourced into the regulator loads flow through
this pin. A chip external decoupling capacitor (100 nF...220 nF, X7R ceramic) between VDDR and VSSR
(if VSSR is not available VSS) can smooth ripple on VDDR.
For entering Shutdown Mode, pin VDDR should also be tied to ground on devices without VREGEN pin.
17.2.2
VDDA, VSSA — Regulator Reference Supply Pins
Signals VDDA/VSSA, which are supposed to be relatively quiet, are used to supply the analog parts of the
regulator. Internal precision reference circuits are supplied from these signals. A chip external decoupling
capacitor (100 nF...220 nF, X7R ceramic) between VDDA and VSSA can further improve the quality of
this supply.
17.2.3
VDD, VSS — Regulator Output1 (Core Logic) Pins
Signals VDD/VSS are the primary outputs of VREG_3V3 that provide the power supply for the core logic.
These signals are connected to device pins to allow external decoupling capacitors (220 nF, X7R ceramic).
S12XS Family Reference Manual, Rev. 1.10
492
Freescale Semiconductor
Voltage Regulator (S12VREGL3V3V1)
In Shutdown Mode an external supply driving VDD/VSS can replace the voltage regulator.
17.2.4
VDDF — Regulator Output2 (NVM Logic) Pins
Signals VDDF/VSS are the secondary outputs of VREG_3V3 that provide the power supply for the NVM
logic. These signals are connected to device pins to allow external decoupling capacitors (220 nF, X7R
ceramic).
In Shutdown Mode an external supply driving VDDF/VSS can replace the voltage regulator.
17.2.5
VDDPLL, VSSPLL — Regulator Output3 (PLL) Pins
Signals VDDPLL/VSSPLL are the secondary outputs of VREG_3V3 that provide the power supply for
the PLL and oscillator. These signals are connected to device pins to allow external decoupling capacitors
(100 nF...220 nF, X7R ceramic).
In Shutdown Mode, an external supply driving VDDPLL/VSSPLL can replace the voltage regulator.
17.2.6
VDDX — Power Input Pin
Signals VDDX/VSS are monitored by VREG_3V3 with the LVR feature.
17.2.7
VREGEN — Optional Regulator Enable Pin
This optional signal is used to shutdown VREG_3V3. In that case, VDD/VSS and VDDPLL/VSSPLL
must be provided externally. Shutdown mode is entered with VREGEN being low. If VREGEN is high,
the VREG_3V3 is either in Full Performance Mode or in Reduced Power Mode.
For the connectivity of VREGEN, see device specification.
NOTE
Switching from FPM or RPM to shutdown of VREG_3V3 and vice versa
is not supported while MCU is powered.
17.2.8
VREG_API — Optional Autonomous Periodical Interrupt Output Pin
This pin provides the signal selected via APIEA if system is set accordingly. See 17.3.2.3, “Autonomous
Periodical Interrupt Control Register (VREGAPICL) and 17.4.8, “Autonomous Periodical Interrupt (API)
for details.
For the connectivity of VREG_API, see device specification.
17.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in VREG_3V3.
If enabled in the system, the VREG_3V3 will abort all read and write accesses to reserved registers within
it’s memory slice. See device level specification for details.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
493
Voltage Regulator (S12VREGL3V3V1)
17.3.1
Module Memory Map
A summary of the registers associated with the VREG_3V3 sub-block is shown in Table 17-3. Detailed
descriptions of the registers and bits are given in the subsections that follow
Address
Name
Bit 7
0
6
0
5
4
3
0
2
HTDS
VSEL
VAE
HTEN
0
0
0
0
LVDS
0
0
APIFES
APIEA
APIFE
1
Bit 0
HTIE
HTIF
LVIE
LVIF
APIE
APIF
0
0
0x02F0
R
VREGHTCL
W
0x02F1
VREGCTRL
0x02F2
VREGAPIC R
L
W
APICLK
0x02F3
VREGAPIT R
R
W
APITR5
APITR4
APITR3
APITR2
APITR1
APITR0
0x02F4
VREGAPIR R
H
W
APIR15
APIR14
APIR13
APIR12
APIR11
APIR10
APIR9
APIR8
0x02F5
VREGAPIR R
L
W
APIR7
APIR6
APIR5
APIR4
APIR3
APIR2
APIR1
APIR0
0
0
0
0
0
0
0
0
0
0
0
HTTR3
HTTR2
HTTR1
HTTR0
R
W
0x02F6
Reserved
06
R
W
0x02F7
VREGHTTR
R
W
HTOEN
Table 17-3. Register Summary
S12XS Family Reference Manual, Rev. 1.10
494
Freescale Semiconductor
Voltage Regulator (S12VREGL3V3V1)
17.3.2
Register Descriptions
This section describes all the VREG_3V3 registers and their individual bits.
17.3.2.1
High Temperature Control Register (VREGHTCL)
The VREGHTCL register allows to configure the VREG temperature sense features.
0x02F0
R
7
6
0
0
W
Reset
0
0
5
4
3
VSEL
VAE
HTEN
0
1
0
2
1
0
HTIE
HTIF
0
0
HTDS
0
= Unimplemented or Reserved
Table 17-4. VREGHTCL Field Descriptions
Field
7, 6
Reserved
Description
These reserved bits are used for test purposes and writable only in special modes.
They must remain clear for correct temperature sensor operation.
5
VSEL
Voltage Access Select Bit — If set, the bandgap reference voltage VBG can be accessed internally (i.e.
multiplexed to an internal Analog to Digital Converter channel). The internal access must be enabled by bit VAE.
See device level specification for connectivity.
0 An internal temperature proportional voltage VHT can be accessed internally if VAE is set.
1 Bandgap reference voltage VBG can be accessed internally if VAE is set.
4
VAE
Voltage Access Enable Bit — If set, the voltage selected by bit VSEL can be accessed internally (i.e.
multiplexed to an internal Analog to Digital Converter channel). See device level specification for connectivity.
0 Voltage selected by VSEL can not be accessed internally (i.e. External analog input is connected to Analog
to Digital Converter channel).
1 Voltage selected by VSEL can be accessed internally.
3
HTEN
High Temperature Enable Bit — If set the temperature sense is enabled.
0 The temperature sense is disabled.
1 The temperature sense is enabled.
2
HTDS
High Temperature Detect Status Bit —
This read-only status bit reflects the temperature status. Writes have no effect.
0 Temperature TDIE is below level THTID or RPM or Shutdown Mode.
1 Temperature TDIE is above level THTIA and FPM.
1
HTIE
High Temperature Interrupt Enable Bit
0 Interrupt request is disabled.
1 Interrupt will be requested whenever HTIF is set.
0
HTIF
High Temperature Interrupt Flag — HTIF — High Temperature Interrupt Flag
HTIF is set to 1 when HTDS status bit changes. This flag can only be cleared by writing a 1.}Writing a 0 has no
effect. If enabled (HTIE=1), HTIF causes an interrupt request.
0 No change in HTDS bit.
1 HTDS bit has changed.
Note: On entering the reduced power mode the HTIF is not cleared by the VREG.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
495
Voltage Regulator (S12VREGL3V3V1)
17.3.2.2
Control Register (VREGCTRL)
The VREGCTRL register allows the configuration of the VREG_3V3 low-voltage detect features.
0x02F1
R
7
6
5
4
3
2
0
0
0
0
0
LVDS
0
0
0
0
0
W
Reset
0
1
0
LVIE
LVIF
0
0
= Unimplemented or Reserved
Figure 17-2. Control Register (VREGCTRL)
Table 17-5. VREGCTRL Field Descriptions
Field
Description
2
LVDS
Low-Voltage Detect Status Bit — This read-only status bit reflects the input voltage. Writes have no effect.
0 Input voltage VDDA is above level VLVID or RPM or shutdown mode.
1 Input voltage VDDA is below level VLVIA and FPM.
1
LVIE
Low-Voltage Interrupt Enable Bit
0 Interrupt request is disabled.
1 Interrupt will be requested whenever LVIF is set.
0
LVIF
Low-Voltage Interrupt Flag — LVIF is set to 1 when LVDS status bit changes. This flag can only be cleared by
writing a 1. Writing a 0 has no effect. If enabled (LVIE = 1), LVIF causes an interrupt request.
0 No change in LVDS bit.
1 LVDS bit has changed.
Note: On entering the Reduced Power Mode the LVIF is not cleared by the VREG_3V3.
S12XS Family Reference Manual, Rev. 1.10
496
Freescale Semiconductor
Voltage Regulator (S12VREGL3V3V1)
17.3.2.3
Autonomous Periodical Interrupt Control Register (VREGAPICL)
The VREGAPICL register allows the configuration of the VREG_3V3 autonomous periodical interrupt
features.
0x02F2
7
R
W
Reset
APICLK
0
6
5
0
0
0
0
4
3
2
1
0
APIES
APIEA
APIFE
APIE
APIF
0
0
0
0
0
= Unimplemented or Reserved
Figure 17-3. Autonomous Periodical Interrupt Control Register (VREGAPICL)
Table 17-6. VREGAPICL Field Descriptions
Field
7
APICLK
Description
Autonomous Periodical Interrupt Clock Select Bit — Selects the clock source for the API. Writable only if
APIFE = 0; APICLK cannot be changed if APIFE is set by the same write operation.
0 Autonomous periodical interrupt clock used as source.
1 Bus clock used as source.
4
APIES
Autonomous Periodical Interrupt External Select Bit — Selects the waveform at the external pin.If set, at the
external pin a clock is visible with 2 times the selected API Period (Table 17-10). If not set, at the external pin will
be a high pulse at the end of every selected period with the size of half of the min period (Table 17-10). See
device level specification for connectivity.
0 At the external periodic high pulses are visible, if APIEA and APIFE is set.
1 At the external pin a clock is visible, if APIEA and APIFE is set.
3
APIEA
Autonomous Periodical Interrupt External Access Enable Bit — If set, the waveform selected by bit APIES
can be accessed externally. See device level specification for connectivity.
0 Waveform selected by APIES can not be accessed externally.
1 Waveform selected by APIES can be accessed externally, if APIFE is set.
2
APIFE
Autonomous Periodical Interrupt Feature Enable Bit — Enables the API feature and starts the API timer
when set.
0 Autonomous periodical interrupt is disabled.
1 Autonomous periodical interrupt is enabled and timer starts running.
1
APIE
Autonomous Periodical Interrupt Enable Bit
0 API interrupt request is disabled.
1 API interrupt will be requested whenever APIF is set.
0
APIF
Autonomous Periodical Interrupt Flag — APIF is set to 1 when the in the API configured time has elapsed.
This flag can only be cleared by writing a 1 to it. Clearing of the flag has precedence over setting.
Writing a 0 has no effect. If enabled (APIE = 1), APIF causes an interrupt request.
0 API timeout has not yet occurred.
1 API timeout has occurred.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
497
Voltage Regulator (S12VREGL3V3V1)
17.3.2.4
Autonomous Periodical Interrupt Trimming Register (VREGAPITR)
The VREGAPITR register allows to trim the API timeout period.
0x02F3
7
R
W
Reset
6
5
4
3
2
APITR5
APITR4
APITR3
APITR2
APITR1
APITR0
01
01
01
01
01
01
1
0
0
0
0
0
1. Reset value is either 0 or preset by factory. See Section 1 (Device Overview) for details.
= Unimplemented or Reserved
Figure 17-4. Autonomous Periodical Interrupt Trimming Register (VREGAPITR)
Table 17-7. VREGAPITR Field Descriptions
Field
7–2
APITR[5:0]
Description
Autonomous Periodical Interrupt Period Trimming Bits — See Table 17-8 for trimming effects.
Table 17-8. Trimming Effect of APIT
Bit
Trimming Effect
APITR[5]
Increases period
APITR[4]
Decreases period less than APITR[5] increased it
APITR[3]
Decreases period less than APITR[4]
APITR[2]
Decreases period less than APITR[3]
APITR[1]
Decreases period less than APITR[2]
APITR[0]
Decreases period less than APITR[1]
S12XS Family Reference Manual, Rev. 1.10
498
Freescale Semiconductor
Voltage Regulator (S12VREGL3V3V1)
17.3.2.5
Autonomous Periodical Interrupt Rate High and Low Register
(VREGAPIRH / VREGAPIRL)
The VREGAPIRH and VREGAPIRL register allows the configuration of the VREG_3V3 autonomous
periodical interrupt rate.
0x02F4
R
W
Reset
7
6
5
4
3
2
1
0
APIR15
APIR14
APIR13
APIR12
APIR11
APIR10
APIR9
APIR8
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 17-5. Autonomous Periodical Interrupt Rate High Register (VREGAPIRH)
0x02F5
R
W
Reset
7
6
5
4
3
2
1
0
APIR7
APIR6
APIR5
APIR4
APIR3
APIR2
APIR1
APIR0
0
0
0
0
0
0
0
0
Figure 17-6. Autonomous Periodical Interrupt Rate Low Register (VREGAPIRL)
Table 17-9. VREGAPIRH / VREGAPIRL Field Descriptions
Field
Description
15-0
APIR[15:0]
Autonomous Periodical Interrupt Rate Bits — These bits define the timeout period of the API. See Table 1710 for details of the effect of the autonomous periodical interrupt rate bits. Writable only if APIFE = 0 of
VREGAPICL register.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
499
Voltage Regulator (S12VREGL3V3V1)
Table 17-10. Selectable Autonomous Periodical Interrupt Periods
APICLK
APIR[15:0]
Selected Period
0
0000
0.2 ms1
0
0001
0.4 ms1
0
0002
0.6 ms1
0
0003
0.8 ms1
0
0004
1.0 ms1
0
0005
1.2 ms1
0
.....
0
FFFD
13106.8 ms1
0
FFFE
13107.0 ms1
0
FFFF
13107.2 ms1
1
0000
2 * bus clock period
1
0001
4 * bus clock period
1
0002
6 * bus clock period
1
0003
8 * bus clock period
1
0004
10 * bus clock period
1
0005
12 * bus clock period
1
.....
.....
1
FFFD
131068 * bus clock period
1
FFFE
131070 * bus clock period
.....
1
FFFF
131072 * bus clock period
When
trimmed
within
specified
accuracy.
See
electrical
specifications for details.
1
The period can be calculated as follows depending of APICLK:
Period = 2*(APIR[15:0] + 1) * 0.1 ms or period = 2*(APIR[15:0] + 1) * bus clock period
S12XS Family Reference Manual, Rev. 1.10
500
Freescale Semiconductor
Voltage Regulator (S12VREGL3V3V1)
17.3.2.6
Reserved 06
The Reserved 06 is reserved for test purposes.
0x02F6
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 17-7. Reserved 06
17.3.2.7
High Temperature Trimming Register (VREGHTTR)
The VREGHTTR register allows to trim the VREG temperature sense.
Fiption
0x02F7
7
R
W
Reset
HTOEN
0
6
5
4
0
0
0
0
0
0
3
2
1
0
HTTR3
HTTR2
HTTR1
HTTR0
01
01
01
01
1. Reset value is either 0 or preset by factory. See Section 1 (Device Overview) for details.
= Unimplemented or Reserved
Figure 17-8. VREGHTTR
Table 17-11. VREGHTTR field descriptions
Field
7
HTOEN
3–0
HTTR[3:0]
Description
High Temperature Offset Enable Bit — If set the temperature sense offset is enabled
0 The temperature sense offset is disabled
1 The temperature sense offset is enabled
High Temperature Trimming Bits — See Table 23-16 for trimming effects.
Table 17-12. Trimming Effect
Bit
Trimming Effect
HTTR[3]
Increases VHT twice of HTTR[2]
HTTR[2]
Increases VHT twice of HTTR[1]
HTTR[1]
Increases VHT twice of HTTR[0]
HTTR[0]
Increases VHT (to compensate Temperature Offset)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
501
Voltage Regulator (S12VREGL3V3V1)
17.4
Functional Description
17.4.1
General
Module VREG_3V3 is a voltage regulator, as depicted in Figure 17-1. The regulator functional elements
are the regulator core (REG), a low-voltage detect module (LVD), a control block (CTRL), a power-on
reset module (POR), and a low-voltage reset module (LVR)and a high temperature sensor (HTD).
17.4.2
Regulator Core (REG)
Respectively its regulator core has three parallel, independent regulation loops (REG1,REG2 and REG3).
REG1 and REG3 differ only in the amount of current that can be delivered.
The regulators are linear regulator with a bandgap reference when operated in Full Performance Mode.
They act as a voltage clamp in Reduced Power Mode. All load currents flow from input VDDR to VSS or
VSSPLL. The reference circuits are supplied by VDDA and VSSA.
17.4.2.1
Full Performance Mode
In Full Performance Mode, the output voltage is compared with a reference voltage by an operational
amplifier. The amplified input voltage difference drives the gate of an output transistor.
17.4.2.2
Reduced Power Mode
In Reduced Power Mode, the gate of the output transistor is connected directly to a reference voltage to
reduce power consumption. Mode switching from reduced power to full performance requires a transition
time of tvup, if the voltage regulator is enabled.
17.4.3
Low-Voltage Detect (LVD)
Subblock LVD is responsible for generating the low-voltage interrupt (LVI). LVD monitors the input
voltage (VDDA–VSSA) and continuously updates the status flag LVDS. Interrupt flag LVIF is set whenever
status flag LVDS changes its value. The LVD is available in FPM and is inactive in Reduced Power Mode
or Shutdown Mode.
17.4.4
Power-On Reset (POR)
This functional block monitors VDD. If VDD is below VPORD, POR is asserted; if VDD exceeds VPORD,
the POR is deasserted. POR asserted forces the MCU into Reset. POR Deasserted will trigger the poweron sequence.
17.4.5
Low-Voltage Reset (LVR)
Block LVR monitors the supplies VDD, VDDX and VDDF. If one (or more) drops below it’s
corresponding assertion level, signal LVR asserts; if all VDD,VDDX and VDDF supplies are above their
S12XS Family Reference Manual, Rev. 1.10
502
Freescale Semiconductor
Voltage Regulator (S12VREGL3V3V1)
corresponding deassertion levels, signal LVR deasserts. The LVR function is available only in Full
Performance Mode.
17.4.6
HTD - High Temperature Detect
Subblock HTD is responsible for generating the high temperature interrupt (HTI). HTD monitors the die
temperature TDIE and continuously updates the status flag HTDS.
Interrupt flag HTIF is set whenever status flag HTDS changes its value.
The HTD is available in FPM and is inactive in Reduced Power Mode and Shutdown Mode.
The HT Trimming bits HTTR[3:0] can be set so that the temperature offset is zero, if accurate temperature
measurement is desired.
See Table 23-16 for the trimming effect of APITR.
17.4.7
Regulator Control (CTRL)
This part contains the register block of VREG_3V3 and further digital functionality needed to control the
operating modes. CTRL also represents the interface to the digital core logic.
17.4.8
Autonomous Periodical Interrupt (API)
Subblock API can generate periodical interrupts independent of the clock source of the MCU. To enable
the timer, the bit APIFE needs to be set.
The API timer is either clocked by a trimmable internal RC oscillator or the bus clock. Timer operation
will freeze when MCU clock source is selected and bus clock is turned off. See CRG specification for
details. The clock source can be selected with bit APICLK. APICLK can only be written when APIFE is
not set.
The APIR[15:0] bits determine the interrupt period. APIR[15:0] can only be written when APIFE is
cleared. As soon as APIFE is set, the timer starts running for the period selected by APIR[15:0] bits. When
the configured time has elapsed, the flag APIF is set. An interrupt, indicated by flag APIF = 1, is triggered
if interrupt enable bit APIE = 1. The timer is started automatically again after it has set APIF.
The procedure to change APICLK or APIR[15:0] is first to clear APIFE, then write to APICLK or
APIR[15:0], and afterwards set APIFE.
The API Trimming bits APITR[5:0] must be set so the minimum period equals 0.2 ms if stable frequency
is desired.
See Table 17-8 for the trimming effect of APITR.
NOTE
The first period after enabling the counter by APIFE might be reduced by
API start up delay tsdel. The API internal RC oscillator clock is not available
if VREG_3V3 is in Shutdown Mode.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
503
Voltage Regulator (S12VREGL3V3V1)
It is possible to generate with the API a waveform at an external pin by enabling the API by setting APIFE
and enabling the external access with setting APIEA. By setting APIES the waveform can be selected. If
APIES is set, then at the external pin a clock is visible with 2 times the selected API Period (Table 17-10).
If APIES is not set, then at the external pin will be a high pulse at the end of every selected period with the
size of half of the min period (Table 17-10). See device level specification for connectivity.
17.4.9
Resets
This section describes how VREG_3V3 controls the reset of the MCU.The reset values of registers and
signals are provided in Section 17.3, “Memory Map and Register Definition”. Possible reset sources are
listed in Table 17-13.
Table 17-13. Reset Sources
Reset Source
Local Enable
Power-on reset
Always active
Low-voltage reset
Available only in Full Performance Mode
17.4.10 Description of Reset Operation
17.4.10.1 Power-On Reset (POR)
During chip power-up the digital core may not work if its supply voltage VDD is below the POR
deassertion level (VPORD). Therefore, signal POR, which forces the other blocks of the device into reset,
is kept high until VDD exceeds VPORD. The MCU will run the start-up sequence after POR deassertion.
The power-on reset is active in all operation modes of VREG_3V3.
17.4.10.2 Low-Voltage Reset (LVR)
For details on low-voltage reset, see Section 17.4.5, “Low-Voltage Reset (LVR)”.
17.4.11 Interrupts
This section describes all interrupts originated by VREG_3V3.
The interrupt vectors requested by VREG_3V3 are listed in Table 17-14. Vector addresses and interrupt
priorities are defined at MCU level.
Table 17-14. Interrupt Vectors
Interrupt Source
Local Enable
Low-voltage interrupt (LVI)
LVIE = 1; available only in Full Performance
Mode
High Temperature Interrupt (HTI)
HTIE=1;
available only in Full Performance Mode
Autonomous periodical interrupt (API)
APIE = 1
S12XS Family Reference Manual, Rev. 1.10
504
Freescale Semiconductor
Voltage Regulator (S12VREGL3V3V1)
17.4.11.1 Low-Voltage Interrupt (LVI)
In FPM, VREG_3V3 monitors the input voltage VDDA. Whenever VDDA drops below level VLVIA, the
status bit LVDS is set to 1. On the other hand, LVDS is reset to 0 when VDDA rises above level VLVID. An
interrupt, indicated by flag LVIF = 1, is triggered by any change of the status bit LVDS if interrupt enable
bit LVIE = 1.
NOTE
On entering the Reduced Power Mode, the LVIF is not cleared by the
VREG_3V3.
17.4.11.2 HTI - High Temperature Interrupt
In FPM VREG monitors the die temperature TDIE. Whenever TDIE exceeds level THTIA the status bit
HTDS is set to 1. Vice versa, HTDS is reset to 0 when TDIE get below level THTID. An interrupt, indicated
by flag HTIF=1, is triggered by any change of the status bit HTDS if interrupt enable bit HTIE=1.
NOTE
On entering the Reduced Power Mode the HTIF is not cleared by the VREG.
17.4.11.3 Autonomous Periodical Interrupt (API)
As soon as the configured timeout period of the API has elapsed, the APIF bit is set. An interrupt, indicated
by flag APIF = 1, is triggered if interrupt enable bit APIE = 1.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
505
Voltage Regulator (S12VREGL3V3V1)
S12XS Family Reference Manual, Rev. 1.10
506
Freescale Semiconductor
Chapter 18
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-1. Revision History
Revision
Number
Revision
Date
V01.04
03 Jan 2008
V01.05
19 Dec 2008
18.1/18-507
18.4.2.4/18-542
18.4.2.6/18-544
18.4.2.11/18-54
7
18.4.2.11/18-54
7
18.4.2.11/18-54
7
V01.06
25 Sep 2009
The following changes were made to clarify module behavior related to Flash
register access during reset sequence and while Flash commands are active:
18.3.2/18-514 - Add caution concerning register writes while command is active
18.3.2.1/18-516 - Writes to FCLKDIV are allowed during reset sequence while CCIF is clear
18.4.1.2/18-536 - Add caution concerning register writes while command is active
- Writes to FCCOBIX, FCCOBHI, FCCOBLO registers are ignored during
18.6/18-556
reset sequence
18.1
Sections
Affected
Description of Changes
- Cosmetic changes
- Clarify single bit fault correction for P-Flash phrase
- Add statement concerning code runaway when executing Read Once,
Program Once, and Verify Backdoor Access Key commands from Flash block
containing associated fields
- Relate Key 0 to associated Backdoor Comparison Key address
- Change “power down reset” to “reset” in Section 18.4.2.11
Introduction
The FTMR256K1 module implements the following:
• 256 Kbytes of P-Flash (Program Flash) memory
• 8 Kbytes of D-Flash (Data Flash) memory
The Flash memory is ideal for single-supply applications allowing for field reprogramming without
requiring external high voltage sources for program or erase operations. The Flash module includes a
memory controller that executes commands to modify Flash memory contents. The user interface to the
memory controller consists of the indexed Flash Common Command Object (FCCOB) register which is
written to with the command, global address, data, and any required command parameters. The memory
controller must complete the execution of a command before the FCCOB register can be written to with a
new command.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
507
CAUTION
A Flash word or phrase must be in the erased state before being
programmed. Cumulative programming of bits within a Flash word or
phrase is not allowed.
The Flash memory may be read as bytes, aligned words, or misaligned words. Read access time is one bus
cycle for bytes and aligned words, and two bus cycles for misaligned words. For Flash memory, an erased
bit reads 1 and a programmed bit reads 0.
It is not possible to read from a Flash block while any command is executing on that specific Flash block.
It is possible to read from a Flash block while a command is executing on a different Flash block.
Both P-Flash and D-Flash memories are implemented with Error Correction Codes (ECC) that can resolve
single bit faults and detect double bit faults. For P-Flash memory, the ECC implementation requires that
programming be done on an aligned 8 byte basis (a Flash phrase). Since P-Flash memory is always read
by phrase, only one single bit fault in the phrase containing the byte or word accessed will be corrected.
18.1.1
Glossary
Command Write Sequence — An MCU instruction sequence to execute built-in algorithms (including
program and erase) on the Flash memory.
D-Flash Memory — The D-Flash memory constitutes the nonvolatile memory store for data.
D-Flash Sector — The D-Flash sector is the smallest portion of the D-Flash memory that can be erased.
The D-Flash sector consists of four 64 byte rows for a total of 256 bytes.
NVM Command Mode — An NVM mode using the CPU to setup the FCCOB register to pass parameters
required for Flash command execution.
Phrase — An aligned group of four 16-bit words within the P-Flash memory. Each phrase includes eight
ECC bits for single bit fault correction and double bit fault detection within the phrase.
P-Flash Memory — The P-Flash memory constitutes the main nonvolatile memory store for applications.
P-Flash Sector — The P-Flash sector is the smallest portion of the P-Flash memory that can be erased.
Each P-Flash sector contains 1024 bytes.
Program IFR — Nonvolatile information register located in the P-Flash block that contains the Device
ID, Version ID, and the Program Once field. The Program IFR is visible in the global memory map by
setting the PGMIFRON bit in the MMCCTL1 register.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
508
256 KByte Flash Module (S12XFTMR256K1V1)
18.1.2
18.1.2.1
•
•
•
•
•
•
•
•
•
•
D-Flash Features
8 Kbytes of D-Flash memory composed of one 8 Kbyte Flash block divided into 32 sectors of 256
bytes
Single bit fault correction and double bit fault detection within a word during read operations
Automated program and erase algorithm with verify and generation of ECC parity bits
Fast sector erase and word program operation
Protection scheme to prevent accidental program or erase of D-Flash memory
Ability to program up to four words in a burst sequence
18.1.2.3
•
•
•
P-Flash Features
256 Kbytes of P-Flash memory composed of one 256 Kbyte Flash block divided into 256 sectors
of 1024 bytes
Single bit fault correction and double bit fault detection within a 64-bit phrase during read
operations
Automated program and erase algorithm with verify and generation of ECC parity bits
Fast sector erase and phrase program operation
Flexible protection scheme to prevent accidental program or erase of P-Flash memory
18.1.2.2
•
Features
Other Flash Module Features
No external high-voltage power supply required for Flash memory program and erase operations
Interrupt generation on Flash command completion and Flash error detection
Security mechanism to prevent unauthorized access to the Flash memory
18.1.3
Block Diagram
The block diagram of the Flash module is shown in Figure 18-1.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
509
256 KByte Flash Module (S12XFTMR256K1V1)
Flash
Interface
Command
Interrupt
Request
Registers
Error
Interrupt
Request
Protection
16bit
internal
bus
P-Flash
32Kx72
16Kx72
16Kx72
sector 0
sector 1
sector 0
sector 1
sector 127
sector 127
Security
Oscillator
Clock (XTAL)
CPU
Clock
Divider FCLK
Memory
Controller
D-Flash
4Kx22
Scratch RAM
384x16
sector 0
sector 1
sector 31
Figure 18-1. FTMR256K1 Block Diagram
18.2
External Signal Description
The Flash module contains no signals that connect off-chip.
18.3
Memory Map and Registers
This section describes the memory map and registers for the Flash module. Read data from unimplemented
memory space in the Flash module is undefined. Write access to unimplemented or reserved memory space
in the Flash module will be ignored by the Flash module.
S12XS Family Reference Manual, Rev. 1.10
510
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
18.3.1
Module Memory Map
The S12X architecture places the P-Flash memory between global addresses 0x7C_0000 and 0x7F_FFFF
as shown in Table 18-2. The P-Flash memory map is shown in Figure 18-2.
Table 18-2. P-Flash Memory Addressing
Global Address
Size
(Bytes)
0x7C_0000 – 0x7F_FFFF
256 K
Description
P-Flash Block 0
Contains Flash Configuration Field
(see Table 18-3)
The FPROT register, described in Section 18.3.2.9, can be set to protect regions in the Flash memory from
accidental program or erase. Three separate memory regions, one growing upward from global address
0x7F_8000 in the Flash memory (called the lower region), one growing downward from global address
0x7F_FFFF in the Flash memory (called the higher region), and the remaining addresses in the Flash
memory, can be activated for protection. The Flash memory addresses covered by these protectable regions
are shown in the P-Flash memory map. The higher address region is mainly targeted to hold the boot loader
code since it covers the vector space. Default protection settings as well as security information that allows
the MCU to restrict access to the Flash module are stored in the Flash configuration field as described in
Table 18-3.
Table 18-3. Flash Configuration Field1
Global Address
Size
(Bytes)
0x7F_FF00 – 0x7F_FF07
8
Backdoor Comparison Key
Refer to Section 18.4.2.11, “Verify Backdoor Access Key Command,” and
Section 18.5.1, “Unsecuring the MCU using Backdoor Key Access”
0x7F_FF08 – 0x7F_FF0B2
4
Reserved
0x7F_FF0C2
1
P-Flash Protection byte.
Refer to Section 18.3.2.9, “P-Flash Protection Register (FPROT)”
0x7F_FF0D2
1
D-Flash Protection byte.
Refer to Section 18.3.2.10, “D-Flash Protection Register (DFPROT)”
0x7F_FF0E2
1
Flash Nonvolatile byte
Refer to Section 18.3.2.15, “Flash Option Register (FOPT)”
0x7F_FF0F2
1
Flash Security byte
Refer to Section 18.3.2.2, “Flash Security Register (FSEC)”
1
2
Description
Older versions may have swapped protection byte addresses
0x7FF08 - 0x7F_FF0F form a Flash phrase and must be programmed in a single command write sequence. Each byte in
the 0x7F_FF08 - 0x7F_FF0B reserved field should be programmed to 0xFF.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
511
256 KByte Flash Module (S12XFTMR256K1V1)
P-Flash START = 0x7C_0000
Flash Protected/Unprotected Region
224 Kbytes
0x7F_8000
0x7F_8400
0x7F_8800
0x7F_9000
Flash Protected/Unprotected Lower Region
1, 2, 4, 8 Kbytes
0x7F_A000
Flash Protected/Unprotected Region
8 Kbytes (up to 29 Kbytes)
0x7F_C000
0x7F_E000
Flash Protected/Unprotected Higher Region
2, 4, 8, 16 Kbytes
0x7F_F000
0x7F_F800
P-Flash END = 0x7F_FFFF
Flash Configuration Field
16 bytes (0x7F_FF00 - 0x7F_FF0F)
Figure 18-2. P-Flash Memory Map
S12XS Family Reference Manual, Rev. 1.10
512
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-4. Program IFR Fields
Global Address
(PGMIFRON)
Size
(Bytes)
0x40_0000 – 0x40_0007
8
Device ID
0x40_0008 – 0x40_00E7
224
Reserved
0x40_00E8 – 0x40_00E9
2
Version ID
0x40_00EA – 0x40_00FF
22
Reserved
0x40_0100 – 0x40_013F
64
Program Once Field
Refer to Section 18.4.2.6, “Program Once Command”
0x40_0140 – 0x40_01FF
192
Reserved
Field Description
Table 18-5. D-Flash and Memory Controller Resource Fields
Global Address
Size
(Bytes)
0x10_0000 – 0x10_1FFF
8,192
0x10_2000 – 0x11_FFFF
122,880
0x12_0000 – 0x12_007F
128
0x12_0080 – 0x12_0FFF
3,968
Reserved
0x12_1000 – 0x12_1FFF
4,096
Reserved
0x12_2000 – 0x12_3CFF
7,242
Reserved
0x12_3D00 – 0x12_3FFF
768
0x12_4000 – 0x12_E7FF
43,008
Reserved
0x12_E800 – 0x12_FFFF
6,144
Reserved
0x13_0000 – 0x13_FFFF
65,536
Reserved
1
Description
D-Flash Memory
Reserved
D-Flash Nonvolatile Information Register (DFIFRON1 = 1)
Memory Controller Scratch RAM (MGRAMON1 = 1)
MMCCTL1 register bit
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
513
256 KByte Flash Module (S12XFTMR256K1V1)
D-Flash START = 0x10_0000
D-Flash Memory
8 Kbytes
D-Flash END = 0x10_1FFF
0x12_0000
D-Flash Nonvolatile Information Register (DFIFRON)
128 bytes
0x12_1000
0x12_2000
Memory Controller Scratch RAM (MGRAMON)
768 bytes
0x12_4000
0x12_E800
0x12_FFFF
Figure 18-3. D-Flash and Memory Controller Resource Memory Map
18.3.2
Register Descriptions
The Flash module contains a set of 20 control and status registers located between Flash module base +
0x0000 and 0x0013. A summary of the Flash module registers is given in Figure 18-4 with detailed
descriptions in the following subsections.
CAUTION
Writes to any Flash register must be avoided while a Flash command is
active (CCIF=0) to prevent corruption of Flash register contents and
Memory Controller behavior.
Address
& Name
0x0000
FCLKDIV
0x0001
FSEC
7
R
6
5
4
3
2
1
0
FDIV6
FDIV5
FDIV4
FDIV3
FDIV2
FDIV1
FDIV0
KEYEN0
RNV5
RNV4
RNV3
RNV2
SEC1
SEC0
FDIVLD
W
R
KEYEN1
W
Figure 18-4. FTMR256K1 Register Summary
S12XS Family Reference Manual, Rev. 1.10
514
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Address
& Name
0x0002
FCCOBIX
0x0003
FECCRIX
0x0004
FCNFG
0x0005
FERCNFG
0x0006
FSTAT
0x0007
FERSTAT
0x0008
FPROT
0x0009
DFPROT
0x000A
FCCOBHI
0x000B
FCCOBLO
0x000C
FRSV0
0x000D
FRSV1
0x000E
FECCRHI
0x000F
FECCRLO
R
7
6
5
4
3
0
0
0
0
0
2
1
0
CCOBIX2
CCOBIX1
CCOBIX0
ECCRIX2
ECCRIX1
ECCRIX0
FDFD
FSFD
DFDIE
SFDIE
MGSTAT1
MGSTAT0
DFDIF
SFDIF
W
R
0
0
0
0
0
W
R
0
0
CCIE
0
0
IGNSF
W
R
0
W
R
0
CCIF
ACCERR
FPVIOL
0
0
MGBUSY
RSVD
0
0
W
R
0
0
W
R
RNV6
FPOPEN
FPHDIS
FPHS1
FPHS0
FPLDIS
FPLS1
FPLS0
DPS4
DPS3
DPS2
DPS1
DPS0
W
R
0
0
DPOPEN
W
R
CCOB15
CCOB14
CCOB13
CCOB12
CCOB11
CCOB10
CCOB9
CCOB8
CCOB7
CCOB6
CCOB5
CCOB4
CCOB3
CCOB2
CCOB1
CCOB0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ECCR15
ECCR14
ECCR13
ECCR12
ECCR11
ECCR10
ECCR9
ECCR8
ECCR7
ECCR6
ECCR5
ECCR4
ECCR3
ECCR2
ECCR1
ECCR0
W
R
W
R
W
R
W
R
W
R
W
Figure 18-4. FTMR256K1 Register Summary (continued)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
515
256 KByte Flash Module (S12XFTMR256K1V1)
Address
& Name
0x0010
FOPT
0x0011
FRSV2
0x0012
FRSV3
0x0013
FRSV4
R
7
6
5
4
3
2
1
0
NV7
NV6
NV5
NV4
NV3
NV2
NV1
NV0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
R
W
R
W
R
W
= Unimplemented or Reserved
Figure 18-4. FTMR256K1 Register Summary (continued)
18.3.2.1
Flash Clock Divider Register (FCLKDIV)
The FCLKDIV register is used to control timed events in program and erase algorithms.
Offset Module Base + 0x0000
7
R
6
5
4
3
2
1
0
0
0
0
FDIVLD
FDIV[6:0]
W
Reset
0
0
0
0
0
= Unimplemented or Reserved
Figure 18-5. Flash Clock Divider Register (FCLKDIV)
All bits in the FCLKDIV register are readable, bits 6–0 are write once and bit 7 is not writable.
Table 18-6. FCLKDIV Field Descriptions
Field
7
FDIVLD
6–0
FDIV[6:0]
Description
Clock Divider Loaded
0 FCLKDIV register has not been written
1 FCLKDIV register has been written since the last reset
Clock Divider Bits — FDIV[6:0] must be set to effectively divide OSCCLK down to generate an internal Flash
clock, FCLK, with a target frequency of 1 MHz for use by the Flash module to control timed events during program
and erase algorithms. Table 18-7 shows recommended values for FDIV[6:0] based on OSCCLK frequency.
Please refer to Section 18.4.1, “Flash Command Operations,” for more information.
S12XS Family Reference Manual, Rev. 1.10
516
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
CAUTION
The FCLKDIV register should never be written while a Flash command is
executing (CCIF=0). The FCLKDIV register is writable during the Flash
reset sequence even though CCIF is clear.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
517
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-7. FDIV vs OSCCLK Frequency
OSCCLK Frequency
(MHz)
1
2
MIN1
MAX
1.60
2.10
2.40
FDIV[6:0]
2
OSCCLK Frequency
(MHz)
FDIV[6:0]
MIN1
2
MAX
0x01
33.60
34.65
0x20
3.15
0x02
34.65
35.70
0x21
3.20
4.20
0x03
35.70
36.75
0x22
4.20
5.25
0x04
36.75
37.80
0x23
5.25
6.30
0x05
37.80
38.85
0x24
6.30
7.35
0x06
38.85
39.90
0x25
7.35
8.40
0x07
39.90
40.95
0x26
8.40
9.45
0x08
40.95
42.00
0x27
9.45
10.50
0x09
42.00
43.05
0x28
10.50
11.55
0x0A
43.05
44.10
0x29
11.55
12.60
0x0B
44.10
45.15
0x2A
12.60
13.65
0x0C
45.15
46.20
0x2B
13.65
14.70
0x0D
46.20
47.25
0x2C
14.70
15.75
0x0E
47.25
48.30
0x2D
15.75
16.80
0x0F
48.30
49.35
0x2E
16.80
17.85
0x10
49.35
50.40
0x2F
17.85
18.90
0x11
18.90
19.95
0x12
19.95
21.00
0x13
21.00
22.05
0x14
22.05
23.10
0x15
23.10
24.15
0x16
24.15
25.20
0x17
25.20
26.25
0x18
26.25
27.30
0x19
27.30
28.35
0x1A
28.35
29.40
0x1B
29.40
30.45
0x1C
30.45
31.50
0x1D
31.50
32.55
0x1E
32.55
33.60
0x1F
FDIV shown generates an FCLK frequency of >0.8 MHz
FDIV shown generates an FCLK frequency of 1.05 MHz
S12XS Family Reference Manual, Rev. 1.10
518
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
18.3.2.2
Flash Security Register (FSEC)
The FSEC register holds all bits associated with the security of the MCU and Flash module.
Offset Module Base + 0x0001
7
R
6
5
4
KEYEN[1:0]
3
2
1
RNV[5:2]
0
SEC[1:0]
W
Reset
F
F
F
F
F
F
F
F
= Unimplemented or Reserved
Figure 18-6. Flash Security Register (FSEC)
All bits in the FSEC register are readable but not writable.
During the reset sequence, the FSEC register is loaded with the contents of the Flash security byte in the
Flash configuration field at global address 0x7F_FF0F located in P-Flash memory (see Table 18-3) as
indicated by reset condition F in Figure 18-6. If a double bit fault is detected while reading the P-Flash
phrase containing the Flash security byte during the reset sequence, all bits in the FSEC register will be
set to leave the Flash module in a secured state with backdoor key access disabled.
Table 18-8. FSEC Field Descriptions
Field
Description
7–6
Backdoor Key Security Enable Bits — The KEYEN[1:0] bits define the enabling of backdoor key access to the
KEYEN[1:0] Flash module as shown in Table 18-9.
5–2
RNV[5:2}
Reserved Nonvolatile Bits — The RNV bits should remain in the erased state for future enhancements.
1–0
SEC[1:0]
Flash Security Bits — The SEC[1:0] bits define the security state of the MCU as shown in Table 18-10. If the
Flash module is unsecured using backdoor key access, the SEC bits are forced to 10.
Table 18-9. Flash KEYEN States
1
KEYEN[1:0]
Status of Backdoor Key Access
00
DISABLED
01
DISABLED1
10
ENABLED
11
DISABLED
Preferred KEYEN state to disable backdoor key access.
Table 18-10. Flash Security States
SEC[1:0]
Status of Security
00
SECURED
01
SECURED1
10
UNSECURED
11
SECURED
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
519
256 KByte Flash Module (S12XFTMR256K1V1)
1
Preferred SEC state to set MCU to secured state.
The security function in the Flash module is described in Section 18.5.
18.3.2.3
Flash CCOB Index Register (FCCOBIX)
The FCCOBIX register is used to index the FCCOB register for Flash memory operations.
Offset Module Base + 0x0002
R
7
6
5
4
3
0
0
0
0
0
2
1
0
CCOBIX[2:0]
W
Reset
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 18-7. FCCOB Index Register (FCCOBIX)
CCOBIX bits are readable and writable while remaining bits read 0 and are not writable.
Table 18-11. FCCOBIX Field Descriptions
Field
Description
2–0
CCOBIX[1:0]
Common Command Register Index— The CCOBIX bits are used to select which word of the FCCOB register
array is being read or written to. See Section 18.3.2.11, “Flash Common Command Object Register (FCCOB),”
for more details.
18.3.2.4
Flash ECCR Index Register (FECCRIX)
The FECCRIX register is used to index the FECCR register for ECC fault reporting.
Offset Module Base + 0x0003
R
7
6
5
4
3
0
0
0
0
0
2
1
0
ECCRIX[2:0]
W
Reset
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 18-8. FECCR Index Register (FECCRIX)
ECCRIX bits are readable and writable while remaining bits read 0 and are not writable.
Table 18-12. FECCRIX Field Descriptions
Field
Description
2-0
ECC Error Register Index— The ECCRIX bits are used to select which word of the FECCR register array is
ECCRIX[2:0] being read. See Section 18.3.2.14, “Flash ECC Error Results Register (FECCR),” for more details.
S12XS Family Reference Manual, Rev. 1.10
520
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
18.3.2.5
Flash Configuration Register (FCNFG)
The FCNFG register enables the Flash command complete interrupt and forces ECC faults on Flash array
read access from the CPU or XGATE.
Offset Module Base + 0x0004
7
R
6
5
0
0
CCIE
4
3
2
0
0
IGNSF
1
0
FDFD
FSFD
0
0
W
Reset
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 18-9. Flash Configuration Register (FCNFG)
CCIE, IGNSF, FDFD, and FSFD bits are readable and writable while remaining bits read 0 and are not
writable.
Table 18-13. FCNFG Field Descriptions
Field
Description
7
CCIE
Command Complete Interrupt Enable — The CCIE bit controls interrupt generation when a Flash command
has completed.
0 Command complete interrupt disabled
1 An interrupt will be requested whenever the CCIF flag in the FSTAT register is set (see Section 18.3.2.7)
4
IGNSF
Ignore Single Bit Fault — The IGNSF controls single bit fault reporting in the FERSTAT register (see
Section 18.3.2.8).
0 All single bit faults detected during array reads are reported
1 Single bit faults detected during array reads are not reported and the single bit fault interrupt will not be
generated
1
FDFD
Force Double Bit Fault Detect — The FDFD bit allows the user to simulate a double bit fault during Flash array
read operations and check the associated interrupt routine. The FDFD bit is cleared by writing a 0 to FDFD. The
FECCR registers will not be updated during the Flash array read operation with FDFD set unless an actual
double bit fault is detected.
0 Flash array read operations will set the DFDIF flag in the FERSTAT register only if a double bit fault is detected
1 Any Flash array read operation will force the DFDIF flag in the FERSTAT register to be set (see
Section 18.3.2.7) and an interrupt will be generated as long as the DFDIE interrupt enable in the FERCNFG
register is set (see Section 18.3.2.6)
0
FSFD
Force Single Bit Fault Detect — The FSFD bit allows the user to simulate a single bit fault during Flash array
read operations and check the associated interrupt routine. The FSFD bit is cleared by writing a 0 to FSFD. The
FECCR registers will not be updated during the Flash array read operation with FSFD set unless an actual single
bit fault is detected.
0 Flash array read operations will set the SFDIF flag in the FERSTAT register only if a single bit fault is detected
1 Flash array read operation will force the SFDIF flag in the FERSTAT register to be set (see Section 18.3.2.7)
and an interrupt will be generated as long as the SFDIE interrupt enable in the FERCNFG register is set (see
Section 18.3.2.6)
18.3.2.6
Flash Error Configuration Register (FERCNFG)
The FERCNFG register enables the Flash error interrupts for the FERSTAT flags.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
521
256 KByte Flash Module (S12XFTMR256K1V1)
Offset Module Base + 0x0005
7
6
R
5
4
3
2
1
0
DFDIE
SFDIE
0
0
0
W
Reset
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 18-10. Flash Error Configuration Register (FERCNFG)
All assigned bits in the FERCNFG register are readable and writable.
Table 18-14. FERCNFG Field Descriptions
Field
Description
1
DFDIE
Double Bit Fault Detect Interrupt Enable — The DFDIE bit controls interrupt generation when a double bit fault
is detected during a Flash block read operation.
0 DFDIF interrupt disabled
1 An interrupt will be requested whenever the DFDIF flag is set (see Section 18.3.2.8)
0
SFDIE
Single Bit Fault Detect Interrupt Enable — The SFDIE bit controls interrupt generation when a single bit fault
is detected during a Flash block read operation.
0 SFDIF interrupt disabled whenever the SFDIF flag is set (see Section 18.3.2.8)
1 An interrupt will be requested whenever the SFDIF flag is set (see Section 18.3.2.8)
18.3.2.7
Flash Status Register (FSTAT)
The FSTAT register reports the operational status of the Flash module.
Offset Module Base + 0x0006
7
R
6
5
4
ACCERR
FPVIOL
0
0
0
CCIF
3
2
MGBUSY
RSVD
0
0
1
0
MGSTAT[1:0]
W
Reset
1
0
01
01
= Unimplemented or Reserved
Figure 18-11. Flash Status Register (FSTAT)
1
Reset value can deviate from the value shown if a double bit fault is detected during the reset sequence (see Section 18.6).
CCIF, ACCERR, and FPVIOL bits are readable and writable, MGBUSY and MGSTAT bits are readable
but not writable, while remaining bits read 0 and are not writable.
S12XS Family Reference Manual, Rev. 1.10
522
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-15. FSTAT Field Descriptions
Field
Description
7
CCIF
Command Complete Interrupt Flag — The CCIF flag indicates that a Flash command has completed. The
CCIF flag is cleared by writing a 1 to CCIF to launch a command and CCIF will stay low until command
completion or command violation.
0 Flash command in progress
1 Flash command has completed
5
ACCERR
Flash Access Error Flag — The ACCERR bit indicates an illegal access has occurred to the Flash memory
caused by either a violation of the command write sequence (see Section 18.4.1.2) or issuing an illegal Flash
command. While ACCERR is set, the CCIF flag cannot be cleared to launch a command. The ACCERR bit is
cleared by writing a 1 to ACCERR. Writing a 0 to the ACCERR bit has no effect on ACCERR.
0 No access error detected
1 Access error detected
4
FPVIOL
Flash Protection Violation Flag —The FPVIOL bit indicates an attempt was made to program or erase an
address in a protected area of P-Flash or D-Flash memory during a command write sequence. The FPVIOL
bit is cleared by writing a 1 to FPVIOL. Writing a 0 to the FPVIOL bit has no effect on FPVIOL. While FPVIOL
is set, it is not possible to launch a command or start a command write sequence.
0 No protection violation detected
1 Protection violation detected
3
MGBUSY
2
RSVD
Memory Controller Busy Flag — The MGBUSY flag reflects the active state of the Memory Controller.
0 Memory Controller is idle
1 Memory Controller is busy executing a Flash command (CCIF = 0)
Reserved Bit — This bit is reserved and always reads 0.
1–0
Memory Controller Command Completion Status Flag — One or more MGSTAT flag bits are set if an error
MGSTAT[1:0] is detected during execution of a Flash command or during the Flash reset sequence. See Section 18.4.2,
“Flash Command Description,” and Section 18.6, “Initialization” for details.
18.3.2.8
Flash Error Status Register (FERSTAT)
The FERSTAT register reflects the error status of internal Flash operations.
Offset Module Base + 0x0007
R
7
6
5
4
3
2
0
0
0
0
0
0
1
0
DFDIF
SFDIF
0
0
W
Reset
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 18-12. Flash Error Status Register (FERSTAT)
All flags in the FERSTAT register are readable and only writable to clear the flag.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
523
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-16. FERSTAT Field Descriptions
Field
Description
1
DFDIF
Double Bit Fault Detect Interrupt Flag — The setting of the DFDIF flag indicates that a double bit fault was
detected in the stored parity and data bits during a Flash array read operation or that a Flash array read operation
was attempted on a Flash block that was under a Flash command operation. The DFDIF flag is cleared by writing
a 1 to DFDIF. Writing a 0 to DFDIF has no effect on DFDIF.
0 No double bit fault detected
1 Double bit fault detected or an invalid Flash array read operation attempted
0
SFDIF
Single Bit Fault Detect Interrupt Flag — With the IGNSF bit in the FCNFG register clear, the SFDIF flag
indicates that a single bit fault was detected in the stored parity and data bits during a Flash array read operation
or that a Flash array read operation was attempted on a Flash block that was under a Flash command operation.
The SFDIF flag is cleared by writing a 1 to SFDIF. Writing a 0 to SFDIF has no effect on SFDIF.
0 No single bit fault detected
1 Single bit fault detected and corrected or an invalid Flash array read operation attempted
18.3.2.9
P-Flash Protection Register (FPROT)
The FPROT register defines which P-Flash sectors are protected against program and erase operations.
Offset Module Base + 0x0008
7
R
6
5
4
3
2
1
0
RNV6
FPOPEN
FPHDIS
FPHS[1:0]
FPLDIS
FPLS[1:0]
W
Reset
F
F
F
F
F
F
F
F
= Unimplemented or Reserved
Figure 18-13. Flash Protection Register (FPROT)
The (unreserved) bits of the FPROT register are writable with the restriction that the size of the protected
region can only be increased (see Section 18.3.2.9.1, “P-Flash Protection Restrictions,” and Table 18-21).
During the reset sequence, the FPROT register is loaded with the contents of the P-Flash protection byte
in the Flash configuration field at global address 0x7F_FF0C located in P-Flash memory (see Table 18-3)
as indicated by reset condition ‘F’ in Figure 18-13. To change the P-Flash protection that will be loaded
during the reset sequence, the upper sector of the P-Flash memory must be unprotected, then the P-Flash
protection byte must be reprogrammed. If a double bit fault is detected while reading the P-Flash phrase
containing the P-Flash protection byte during the reset sequence, the FPOPEN bit will be cleared and
remaining bits in the FPROT register will be set to leave the P-Flash memory fully protected.
Trying to alter data in any protected area in the P-Flash memory will result in a protection violation error
and the FPVIOL bit will be set in the FSTAT register. The block erase of a P-Flash block is not possible
if any of the P-Flash sectors contained in the same P-Flash block are protected.
S12XS Family Reference Manual, Rev. 1.10
524
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-17. FPROT Field Descriptions
Field
Description
7
FPOPEN
Flash Protection Operation Enable — The FPOPEN bit determines the protection function for program or
erase operations as shown in Table 18-18 for the P-Flash block.
0 When FPOPEN is clear, the FPHDIS and FPLDIS bits define unprotected address ranges as specified by the
corresponding FPHS and FPLS bits
1 When FPOPEN is set, the FPHDIS and FPLDIS bits enable protection for the address range specified by the
corresponding FPHS and FPLS bits
6
RNV[6]
Reserved Nonvolatile Bit — The RNV bit should remain in the erased state for future enhancements.
5
FPHDIS
Flash Protection Higher Address Range Disable — The FPHDIS bit determines whether there is a
protected/unprotected area in a specific region of the P-Flash memory ending with global address 0x7F_FFFF.
0 Protection/Unprotection enabled
1 Protection/Unprotection disabled
4–3
FPHS[1:0]
Flash Protection Higher Address Size — The FPHS bits determine the size of the protected/unprotected area
in P-Flash memory as shown inTable 18-19. The FPHS bits can only be written to while the FPHDIS bit is set.
2
FPLDIS
1–0
FPLS[1:0]
Flash Protection Lower Address Range Disable — The FPLDIS bit determines whether there is a
protected/unprotected area in a specific region of the P-Flash memory beginning with global address
0x7F_8000.
0 Protection/Unprotection enabled
1 Protection/Unprotection disabled
Flash Protection Lower Address Size — The FPLS bits determine the size of the protected/unprotected area
in P-Flash memory as shown in Table 18-20. The FPLS bits can only be written to while the FPLDIS bit is set.
Table 18-18. P-Flash Protection Function
1
Function1
FPOPEN
FPHDIS
FPLDIS
1
1
1
No P-Flash Protection
1
1
0
Protected Low Range
1
0
1
Protected High Range
1
0
0
Protected High and Low Ranges
0
1
1
Full P-Flash Memory Protected
0
1
0
Unprotected Low Range
0
0
1
Unprotected High Range
0
0
0
Unprotected High and Low Ranges
For range sizes, refer to Table 18-19 and Table 18-20.
Table 18-19. P-Flash Protection Higher Address Range
FPHS[1:0]
Global Address Range
Protected Size
00
0x7F_F800–0x7F_FFFF
2 Kbytes
01
0x7F_F000–0x7F_FFFF
4 Kbytes
10
0x7F_E000–0x7F_FFFF
8 Kbytes
11
0x7F_C000–0x7F_FFFF
16 Kbytes
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
525
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-20. P-Flash Protection Lower Address Range
FPLS[1:0]
Global Address Range
Protected Size
00
0x7F_8000–0x7F_83FF
1 Kbyte
01
0x7F_8000–0x7F_87FF
2 Kbytes
10
0x7F_8000–0x7F_8FFF
4 Kbytes
11
0x7F_8000–0x7F_9FFF
8 Kbytes
All possible P-Flash protection scenarios are shown in Figure 18-14. Although the protection scheme is
loaded from the Flash memory at global address 0x7F_FF0C during the reset sequence, it can be changed
by the user. The P-Flash protection scheme can be used by applications requiring reprogramming in single
chip mode while providing as much protection as possible if reprogramming is not required.
S12XS Family Reference Manual, Rev. 1.10
526
Freescale Semiconductor
FPHDIS = 1
FPLDIS = 1
FPHDIS = 1
FPLDIS = 0
FPHDIS = 0
FPLDIS = 1
FPHDIS = 0
FPLDIS = 0
7
6
5
4
3
2
1
0
Scenario
0x7F_8000
0x7F_FFFF
Scenario
FPHS[1:0]
FPLS[1:0]
FLASH START
FPOPEN = 1
256 KByte Flash Module (S12XFTMR256K1V1)
FPHS[1:0]
0x7F_8000
FPOPEN = 0
FPLS[1:0]
FLASH START
0x7F_FFFF
Unprotected region
Protected region with size
defined by FPLS
Protected region
not defined by FPLS, FPHS
Protected region with size
defined by FPHS
Figure 18-14. P-Flash Protection Scenarios
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
527
256 KByte Flash Module (S12XFTMR256K1V1)
18.3.2.9.1
P-Flash Protection Restrictions
The general guideline is that P-Flash protection can only be added and not removed. Table 18-21 specifies
all valid transitions between P-Flash protection scenarios. Any attempt to write an invalid scenario to the
FPROT register will be ignored. The contents of the FPROT register reflect the active protection scenario.
See the FPHS and FPLS bit descriptions for additional restrictions.
Table 18-21. P-Flash Protection Scenario Transitions
To Protection Scenario1
From
Protection
Scenario
0
1
2
3
0
X
X
X
X
X
1
X
4
X
X
X
X
X
X
X
X
X
X
6
X
7
1
X
6
7
X
3
5
5
X
X
2
4
X
X
X
X
X
X
Allowed transitions marked with X, see Figure 18-14 for a definition of the scenarios.
18.3.2.10 D-Flash Protection Register (DFPROT)
The DFPROT register defines which D-Flash sectors are protected against program and erase operations.
Offset Module Base + 0x0009
7
R
6
5
0
0
4
3
DPOPEN
2
1
0
F
F
DPS[4:0]
W
Reset
F
0
0
F
F
F
= Unimplemented or Reserved
Figure 18-15. D-Flash Protection Register (DFPROT)
The (unreserved) bits of the DFPROT register are writable with the restriction that protection can be added
but not removed. Writes must increase the DPS value and the DPOEN bit can only be written from 1
(protection disabled) to 0 (protection enabled). If the DPOPEN bit is set, the state of the DPS bits is
irrelevant.
During the reset sequence, the DFPROT register is loaded with the contents of the D-Flash protection byte
in the Flash configuration field at global address 0x7F_FF0D located in P-Flash memory (see Table 18-3)
as indicated by reset condition F in Figure 18-15. To change the D-Flash protection that will be loaded
during the reset sequence, the P-Flash sector containing the D-Flash protection byte must be unprotected,
then the D-Flash protection byte must be programmed. If a double bit fault is detected while reading the
S12XS Family Reference Manual, Rev. 1.10
528
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
P-Flash phrase containing the D-Flash protection byte during the reset sequence, the DPOPEN bit will be
cleared and DPS bits will be set to leave the D-Flash memory fully protected.
Trying to alter data in any protected area in the D-Flash memory will result in a protection violation error
and the FPVIOL bit will be set in the FSTAT register. Block erase of the D-Flash memory is not possible
if any of the D-Flash sectors are protected.
Table 18-22. DFPROT Field Descriptions
Field
Description
7
DPOPEN
D-Flash Protection Control
0 Enables D-Flash memory protection from program and erase with protected address range defined by DPS
bits
1 Disables D-Flash memory protection from program and erase
4–0
DPS[4:0]
D-Flash Protection Size — The DPS[4:0] bits determine the size of the protected area in the D-Flash memory
as shown in Table 18-23.
Table 18-23. D-Flash Protection Address Range
DPS[4:0]
Global Address Range
Protected Size
0_0000
0x10_0000 – 0x10_00FF
256 bytes
0_0001
0x10_0000 – 0x10_01FF
512 bytes
0_0010
0x10_0000 – 0x10_02FF
768 bytes
0_0011
0x10_0000 – 0x10_03FF
1024 bytes
0_0100
0x10_0000 – 0x10_04FF
1280 bytes
0_0101
0x10_0000 – 0x10_05FF
1536 bytes
0_0110
0x10_0000 – 0x10_06FF
1792 bytes
0_0111
0x10_0000 – 0x10_07FF
2048 bytes
0_1000
0x10_0000 – 0x10_08FF
2304 bytes
0_1001
0x10_0000 – 0x10_09FF
2560 bytes
0_1010
0x10_0000 – 0x10_0AFF
2816 bytes
0_1011
0x10_0000 – 0x10_0BFF
3072 bytes
0_1100
0x10_0000 – 0x10_0CFF
3328 bytes
0_1101
0x10_0000 – 0x10_0DFF
3584 bytes
0_1110
0x10_0000 – 0x10_0EFF
3840 bytes
0_1111
0x10_0000 – 0x10_0FFF
4096 bytes
1_0000
0x10_0000 – 0x10_10FF
4352 bytes
1_0001
0x10_0000 – 0x10_11FF
4608 bytes
1_0010
0x10_0000 – 0x10_12FF
4864 bytes
1_0011
0x10_0000 – 0x10_13FF
5120 bytes
1_0100
0x10_0000 – 0x10_14FF
5376 bytes
1_0101
0x10_0000 – 0x10_15FF
5632 bytes
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
529
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-23. D-Flash Protection Address Range
DPS[4:0]
Global Address Range
Protected Size
1_0110
0x10_0000 – 0x10_16FF
5888 bytes
1_0111
0x10_0000 – 0x10_17FF
6144 bytes
1_1000
0x10_0000 – 0x10_18FF
6400 bytes
1_1001
0x10_0000 – 0x10_19FF
6656 bytes
1_1010
0x10_0000 – 0x10_1AFF
6912 bytes
1_1011
0x10_0000 – 0x10_1BFF
7168 bytes
1_1100
0x10_0000 – 0x10_1CFF
7424 bytes
1_1101
0x10_0000 – 0x10_1DFF
7680 bytes
1_1110
0x10_0000 – 0x10_1EFF
7936 bytes
1_1111
0x10_0000 – 0x10_1FFF
8192 bytes
18.3.2.11 Flash Common Command Object Register (FCCOB)
The FCCOB is an array of six words addressed via the CCOBIX index found in the FCCOBIX register.
Byte wide reads and writes are allowed to the FCCOB register.
Offset Module Base + 0x000A
7
6
5
4
3
2
1
0
0
0
0
0
R
CCOB[15:8]
W
Reset
0
0
0
0
Figure 18-16. Flash Common Command Object High Register (FCCOBHI)
Offset Module Base + 0x000B
7
6
5
4
3
2
1
0
0
0
0
0
R
CCOB[7:0]
W
Reset
0
0
0
0
Figure 18-17. Flash Common Command Object Low Register (FCCOBLO)
18.3.2.11.1 FCCOB - NVM Command Mode
NVM command mode uses the indexed FCCOB register to provide a command code and its relevant
parameters to the Memory Controller. The user first sets up all required FCCOB fields and then initiates
the command’s execution by writing a 1 to the CCIF bit in the FSTAT register (a 1 written by the user
clears the CCIF command completion flag to 0). When the user clears the CCIF bit in the FSTAT register
all FCCOB parameter fields are locked and cannot be changed by the user until the command completes
S12XS Family Reference Manual, Rev. 1.10
530
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
(as evidenced by the Memory Controller returning CCIF to 1). Some commands return information to the
FCCOB register array.
The generic format for the FCCOB parameter fields in NVM command mode is shown in Table 18-24.
The return values are available for reading after the CCIF flag in the FSTAT register has been returned to
1 by the Memory Controller. Writes to the unimplemented parameter fields (CCOBIX = 110 and CCOBIX
= 111) are ignored with reads from these fields returning 0x0000.
Table 18-24 shows the generic Flash command format. The high byte of the first word in the CCOB array
contains the command code, followed by the parameters for this specific Flash command. For details on
the FCCOB settings required by each command, see the Flash command descriptions in Section 18.4.2.
Table 18-24. FCCOB - NVM Command Mode (Typical Usage)
CCOBIX[2:0]
Byte
FCCOB Parameter Fields (NVM Command Mode)
HI
FCMD[7:0] defining Flash command
LO
0, Global address [22:16]
HI
Global address [15:8]
LO
Global address [7:0]
HI
Data 0 [15:8]
LO
Data 0 [7:0]
HI
Data 1 [15:8]
LO
Data 1 [7:0]
HI
Data 2 [15:8]
LO
Data 2 [7:0]
HI
Data 3 [15:8]
LO
Data 3 [7:0]
000
001
010
011
100
101
18.3.2.12 Flash Reserved0 Register (FRSV0)
This Flash register is reserved for factory testing.
Offset Module Base + 0x000C
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 18-18. Flash Reserved0 Register (FRSV0)
All bits in the FRSV0 register read 0 and are not writable.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
531
256 KByte Flash Module (S12XFTMR256K1V1)
18.3.2.13 Flash Reserved1 Register (FRSV1)
This Flash register is reserved for factory testing.
Offset Module Base + 0x000D
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 18-19. Flash Reserved1 Register (FRSV1)
All bits in the FRSV1 register read 0 and are not writable.
18.3.2.14 Flash ECC Error Results Register (FECCR)
The FECCR registers contain the result of a detected ECC fault for both single bit and double bit faults.
The FECCR register provides access to several ECC related fields as defined by the ECCRIX index bits
in the FECCRIX register (see Section 18.3.2.4). Once ECC fault information has been stored, no other
fault information will be recorded until the specific ECC fault flag has been cleared. In the event of
simultaneous ECC faults the priority for fault recording is double bit fault over single bit fault.
Offset Module Base + 0x000E
7
6
5
4
R
3
2
1
0
0
0
0
0
ECCR[15:8]
W
Reset
0
0
0
0
= Unimplemented or Reserved
Figure 18-20. Flash ECC Error Results High Register (FECCRHI)
Offset Module Base + 0x000F
7
6
5
4
R
3
2
1
0
0
0
0
0
ECCR[7:0]
W
Reset
0
0
0
0
= Unimplemented or Reserved
Figure 18-21. Flash ECC Error Results Low Register (FECCRLO)
All FECCR bits are readable but not writable.
S12XS Family Reference Manual, Rev. 1.10
532
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-25. FECCR Index Settings
ECCRIX[2:0]
000
FECCR Register Content
Bits [15:8]
Bit[7]
Bits[6:0]
Parity bits read from
Flash block
0
Global address
[22:16]
001
Global address [15:0]
010
Data 0 [15:0]
011
Data 1 [15:0] (P-Flash only)
100
Data 2 [15:0] (P-Flash only)
101
Data 3 [15:0] (P-Flash only)
110
Not used, returns 0x0000 when read
111
Not used, returns 0x0000 when read
Table 18-26. FECCR Index=000 Bit Descriptions
Field
15:8
PAR[7:0]
Description
ECC Parity Bits — Contains the 8 parity bits from the 72 bit wide P-Flash data word or the 6 parity bits,
allocated to PAR[5:0], from the 22 bit wide D-Flash word with PAR[7:6]=00.
6–0
Global Address — The GADDR[22:16] field contains the upper seven bits of the global address having
GADDR[22:16] caused the error.
The P-Flash word addressed by ECCRIX = 001 contains the lower 16 bits of the global address. The
following four words addressed by ECCRIX = 010 to 101 contain the 64-bit wide data phrase. The four
data words and the parity byte are the uncorrected data read from the P-Flash block.
The D-Flash word addressed by ECCRIX = 001 contains the lower 16 bits of the global address. The
uncorrected 16-bit data word is addressed by ECCRIX = 010.
18.3.2.15 Flash Option Register (FOPT)
The FOPT register is the Flash option register.
Offset Module Base + 0x0010
7
6
5
4
R
3
2
1
0
F
F
F
F
NV[7:0]
W
Reset
F
F
F
F
= Unimplemented or Reserved
Figure 18-22. Flash Option Register (FOPT)
All bits in the FOPT register are readable but are not writable.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
533
256 KByte Flash Module (S12XFTMR256K1V1)
During the reset sequence, the FOPT register is loaded from the Flash nonvolatile byte in the Flash
configuration field at global address 0x7F_FF0E located in P-Flash memory (see Table 18-3) as indicated
by reset condition F in Figure 18-22. If a double bit fault is detected while reading the P-Flash phrase
containing the Flash nonvolatile byte during the reset sequence, all bits in the FOPT register will be set.
Table 18-27. FOPT Field Descriptions
Field
Description
7–0
NV[7:0]
Nonvolatile Bits — The NV[7:0] bits are available as nonvolatile bits. Refer to the device user guide for proper
use of the NV bits.
18.3.2.16 Flash Reserved2 Register (FRSV2)
This Flash register is reserved for factory testing.
Offset Module Base + 0x0011
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 18-23. Flash Reserved2 Register (FRSV2)
All bits in the FRSV2 register read 0 and are not writable.
18.3.2.17 Flash Reserved3 Register (FRSV3)
This Flash register is reserved for factory testing.
Offset Module Base + 0x0012
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 18-24. Flash Reserved3 Register (FRSV3)
All bits in the FRSV3 register read 0 and are not writable.
18.3.2.18 Flash Reserved4 Register (FRSV4)
This Flash register is reserved for factory testing.
S12XS Family Reference Manual, Rev. 1.10
534
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Offset Module Base + 0x0013
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 18-25. Flash Reserved4 Register (FRSV4)
All bits in the FRSV4 register read 0 and are not writable.
18.4
Functional Description
18.4.1
Flash Command Operations
Flash command operations are used to modify Flash memory contents.
The next sections describe:
• How to write the FCLKDIV register that is used to generate a time base (FCLK) derived from
OSCCLK for Flash program and erase command operations
• The command write sequence used to set Flash command parameters and launch execution
• Valid Flash commands available for execution
18.4.1.1
Writing the FCLKDIV Register
Prior to issuing any Flash program or erase command after a reset, the user is required to write the
FCLKDIV register to divide OSCCLK down to a target FCLK of 1 MHz. Table 18-7 shows recommended
values for the FDIV field based on OSCCLK frequency.
NOTE
Programming or erasing the Flash memory cannot be performed if the bus
clock runs at less than 1 MHz. Setting FDIV too high can destroy the Flash
memory due to overstress. Setting FDIV too low can result in incomplete
programming or erasure of the Flash memory cells.
When the FCLKDIV register is written, the FDIVLD bit is set automatically. If the FDIVLD bit is 0, the
FCLKDIV register has not been written since the last reset. If the FCLKDIV register has not been written,
any Flash program or erase command loaded during a command write sequence will not execute and the
ACCERR bit in the FSTAT register will set.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
535
256 KByte Flash Module (S12XFTMR256K1V1)
18.4.1.2
Command Write Sequence
The Memory Controller will launch all valid Flash commands entered using a command write sequence.
Before launching a command, the ACCERR and FPVIOL bits in the FSTAT register must be clear (see
Section 18.3.2.7) and the CCIF flag should be tested to determine the status of the current command write
sequence. If CCIF is 0, the previous command write sequence is still active, a new command write
sequence cannot be started, and all writes to the FCCOB register are ignored.
CAUTION
Writes to any Flash register must be avoided while a Flash command is
active (CCIF=0) to prevent corruption of Flash register contents and
Memory Controller behavior.
18.4.1.2.1
Define FCCOB Contents
The FCCOB parameter fields must be loaded with all required parameters for the Flash command being
executed. Access to the FCCOB parameter fields is controlled via the CCOBIX bits in the FCCOBIX
register (see Section 18.3.2.3).
The contents of the FCCOB parameter fields are transferred to the Memory Controller when the user clears
the CCIF command completion flag in the FSTAT register (writing 1 clears the CCIF to 0). The CCIF flag
will remain clear until the Flash command has completed. Upon completion, the Memory Controller will
return CCIF to 1 and the FCCOB register will be used to communicate any results. The flow for a generic
command write sequence is shown in Figure 18-26.
S12XS Family Reference Manual, Rev. 1.10
536
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
START
Read: FCLKDIV register
Clock Register
Written
Check
no
FDIVLD
Set?
yes
Write: FCLKDIV register
Note: FCLKDIV must be set after
each reset
Read: FSTAT register
FCCOB
Availability Check
CCIF
Set?
no
Results from previous Command
yes
Access Error and
Protection Violation
Check
ACCERR/
FPVIOL
Set?
no
yes
Write: FSTAT register
Clear ACCERR/FPVIOL 0x30
Write to FCCOBIX register
to identify specific command
parameter to load.
Write to FCCOB register
to load required command parameter.
More
Parameters?
yes
no
Write: FSTAT register (to launch command)
Clear CCIF 0x80
Read: FSTAT register
Bit Polling for
Command Completion
Check
CCIF Set?
no
yes
EXIT
Figure 18-26. Generic Flash Command Write Sequence Flowchart
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
537
256 KByte Flash Module (S12XFTMR256K1V1)
18.4.1.3
Valid Flash Module Commands
Table 18-28. Flash Commands by Mode
Unsecured
FCMD
1
2
3
4
5
6
7
8
18.4.1.4
Command
Secured
NS1
NX2
SS3
ST4
NS5
NX6
SS7
ST8
0x01
Erase Verify All Blocks
∗
∗
∗
∗
∗
∗
∗
∗
0x02
Erase Verify Block
∗
∗
∗
∗
∗
∗
∗
∗
0x03
Erase Verify P-Flash Section
∗
∗
∗
∗
∗
0x04
Read Once
∗
∗
∗
∗
∗
0x06
Program P-Flash
∗
∗
∗
∗
∗
0x07
Program Once
∗
∗
∗
∗
∗
0x08
Erase All Blocks
∗
∗
∗
∗
0x09
Erase Flash Block
∗
∗
∗
∗
∗
0x0A
Erase P-Flash Sector
∗
∗
∗
∗
∗
0x0B
Unsecure Flash
∗
∗
∗
∗
0x0C
Verify Backdoor Access Key
∗
0x0D
Set User Margin Level
∗
0x0E
Set Field Margin Level
0x10
Erase Verify D-Flash Section
∗
0x11
Program D-Flash
0x12
Erase D-Flash Sector
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
∗
Unsecured Normal Single Chip mode.
Unsecured Normal Expanded mode.
Unsecured Special Single Chip mode.
Unsecured Special Mode.
Secured Normal Single Chip mode.
Secured Normal Expanded mode.
Secured Special Single Chip mode.
Secured Special Mode.
P-Flash Commands
Table 18-29 summarizes the valid P-Flash commands along with the effects of the commands on the
P-Flash block and other resources within the Flash module.
S12XS Family Reference Manual, Rev. 1.10
538
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-29. P-Flash Commands
FCMD
Command
0x01
Erase Verify All
Blocks
0x02
Erase Verify Block
0x03
Erase Verify
P-Flash Section
0x04
Read Once
0x06
Program P-Flash
0x07
Program Once
Program a dedicated 64 byte field in the nonvolatile information register in P-Flash block
0 that is allowed to be programmed only once.
0x08
Erase All Blocks
Erase all P-Flash (and D-Flash) blocks.
An erase of all Flash blocks is only possible when the FPLDIS, FPHDIS, and FPOPEN
bits in the FPROT register and the DPOPEN bit in the DFPROT register are set prior to
launching the command.
0x09
Erase Flash Block
Erase a P-Flash (or D-Flash) block.
An erase of the full P-Flash block is only possible when FPLDIS, FPHDIS and FPOPEN
bits in the FPROT register are set prior to launching the command.
0x0A
Erase P-Flash
Sector
0x0B
Unsecure Flash
0x0C
Verify Backdoor
Access Key
Supports a method of releasing MCU security by verifying a set of security keys.
0x0D
Set User Margin
Level
Specifies a user margin read level for all P-Flash blocks.
0x0E
Set Field Margin
Level
Specifies a field margin read level for all P-Flash blocks (special modes only).
18.4.1.5
Function on P-Flash Memory
Verify that all P-Flash (and D-Flash) blocks are erased.
Verify that a P-Flash block is erased.
Verify that a given number of words starting at the address provided are erased.
Read a dedicated 64 byte field in the nonvolatile information register in P-Flash block 0
that was previously programmed using the Program Once command.
Program a phrase in a P-Flash block.
Erase all bytes in a P-Flash sector.
Supports a method of releasing MCU security by erasing all P-Flash (and D-Flash) blocks
and verifying that all P-Flash (and D-Flash) blocks are erased.
D-Flash Commands
Table 18-30 summarizes the valid D-Flash commands along with the effects of the commands on the
D-Flash block.
Table 18-30. D-Flash Commands
FCMD
Command
0x01
Erase Verify All
Blocks
0x02
Erase Verify Block
0x08
Erase All Blocks
0x09
Erase Flash Block
Function on D-Flash Memory
Verify that all D-Flash (and P-Flash) blocks are erased.
Verify that the D-Flash block is erased.
Erase all D-Flash (and P-Flash) blocks.
An erase of all Flash blocks is only possible when the FPLDIS, FPHDIS, and FPOPEN
bits in the FPROT register and the DPOPEN bit in the DFPROT register are set prior to
launching the command.
Erase a D-Flash (or P-Flash) block.
An erase of the full D-Flash block is only possible when DPOPEN bit in the DFPROT
register is set prior to launching the command.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
539
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-30. D-Flash Commands
FCMD
Command
Function on D-Flash Memory
0x0B
Unsecure Flash
Supports a method of releasing MCU security by erasing all D-Flash (and P-Flash) blocks
and verifying that all D-Flash (and P-Flash) blocks are erased.
0x0D
Set User Margin
Level
Specifies a user margin read level for the D-Flash block.
0x0E
Set Field Margin
Level
Specifies a field margin read level for the D-Flash block (special modes only).
0x10
Erase Verify
D-Flash Section
Verify that a given number of words starting at the address provided are erased.
0x11
Program D-Flash
Program up to four words in the D-Flash block.
0x12
Erase D-Flash
Sector
Erase all bytes in a sector of the D-Flash block.
18.4.2
Flash Command Description
This section provides details of all available Flash commands launched by a command write sequence. The
ACCERR bit in the FSTAT register will be set during the command write sequence if any of the following
illegal steps are performed, causing the command not to be processed by the Memory Controller:
• Starting any command write sequence that programs or erases Flash memory before initializing the
FCLKDIV register
• Writing an invalid command as part of the command write sequence
• For additional possible errors, refer to the error handling table provided for each command
If a Flash block is read during execution of an algorithm (CCIF = 0) on that same block, the read operation
will return invalid data. If the SFDIF or DFDIF flags were not previously set when the invalid read
operation occurred, both the SFDIF and DFDIF flags will be set and the FECCR registers will be loaded
with the global address used in the invalid read operation with the data and parity fields set to all 0.
If the ACCERR or FPVIOL bits are set in the FSTAT register, the user must clear these bits before starting
any command write sequence (see Section 18.3.2.7).
CAUTION
A Flash word or phrase must be in the erased state before being
programmed. Cumulative programming of bits within a Flash word or
phrase is not allowed.
18.4.2.1
Erase Verify All Blocks Command
The Erase Verify All Blocks command will verify that all P-Flash and D-Flash blocks have been erased.
Table 18-31. Erase Verify All Blocks Command FCCOB Requirements
CCOBIX[2:0]
000
FCCOB Parameters
0x01
Not required
S12XS Family Reference Manual, Rev. 1.10
540
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Upon clearing CCIF to launch the Erase Verify All Blocks command, the Memory Controller will verify
that the entire Flash memory space is erased. The CCIF flag will set after the Erase Verify All Blocks
operation has completed.
Table 18-32. Erase Verify All Blocks Command Error Handling
Register
Error Bit
ACCERR
FPVIOL
FSTAT
18.4.2.2
Error Condition
Set if CCOBIX[2:0] != 000 at command launch
None
MGSTAT1
Set if any errors have been encountered during the read
MGSTAT0
Set if any non-correctable errors have been encountered during the read
Erase Verify Block Command
The Erase Verify Block command allows the user to verify that an entire P-Flash or D-Flash block has been
erased. The FCCOB upper global address bits determine which block must be verified.
Table 18-33. Erase Verify Block Command FCCOB Requirements
CCOBIX[2:0]
FCCOB Parameters
000
0x02
Global address [22:16] of the
Flash block to be verified.
Upon clearing CCIF to launch the Erase Verify Block command, the Memory Controller will verify that
the selected P-Flash or D-Flash block is erased. The CCIF flag will set after the Erase Verify Block
operation has completed.
Table 18-34. Erase Verify Block Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 000 at command launch
ACCERR
Set if an invalid global address [22:16] is supplied
FSTAT
18.4.2.3
FPVIOL
None
MGSTAT1
Set if any errors have been encountered during the read
MGSTAT0
Set if any non-correctable errors have been encountered during the read
Erase Verify P-Flash Section Command
The Erase Verify P-Flash Section command will verify that a section of code in the P-Flash memory is
erased. The Erase Verify P-Flash Section command defines the starting point of the code to be verified and
the number of phrases. The section to be verified cannot cross a 256 Kbyte boundary in the P-Flash
memory space.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
541
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-35. Erase Verify P-Flash Section Command FCCOB Requirements
CCOBIX[2:0]
FCCOB Parameters
000
0x03
Global address [22:16] of
a P-Flash block
001
Global address [15:0] of the first phrase to be verified
010
Number of phrases to be verified
Upon clearing CCIF to launch the Erase Verify P-Flash Section command, the Memory Controller will
verify the selected section of Flash memory is erased. The CCIF flag will set after the Erase Verify P-Flash
Section operation has completed.
Table 18-36. Erase Verify P-Flash Section Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 010 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid global address [22:0] is supplied
Set if a misaligned phrase address is supplied (global address [2:0] != 000)
FSTAT
Set if the requested section crosses a 256 Kbyte boundary
FPVIOL
18.4.2.4
None
MGSTAT1
Set if any errors have been encountered during the read
MGSTAT0
Set if any non-correctable errors have been encountered during the read
Read Once Command
The Read Once command provides read access to a reserved 64 byte field (8 phrases) located in the
nonvolatile information register of P-Flash block 0. The Read Once field is programmed using the
Program Once command described in Section 18.4.2.6. The Read Once command must not be executed
from the Flash block containing the Program Once reserved field to avoid code runaway.
Table 18-37. Read Once Command FCCOB Requirements
CCOBIX[2:0]
000
FCCOB Parameters
0x04
Not Required
001
Read Once phrase index (0x0000 - 0x0007)
010
Read Once word 0 value
011
Read Once word 1 value
100
Read Once word 2 value
101
Read Once word 3 value
Upon clearing CCIF to launch the Read Once command, a Read Once phrase is fetched and stored in the
FCCOB indexed register. The CCIF flag will set after the Read Once operation has completed. Valid
S12XS Family Reference Manual, Rev. 1.10
542
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
phrase index values for the Read Once command range from 0x0000 to 0x0007. During execution of the
Read Once command, any attempt to read addresses within P-Flash block will return invalid data.
Table 18-38. Read Once Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 001 at command launch
ACCERR
Set if command not available in current mode (see Table 18-28)
Set if an invalid phrase index is supplied
FSTAT
FPVIOL
18.4.2.5
None
MGSTAT1
Set if any errors have been encountered during the read
MGSTAT0
Set if any non-correctable errors have been encountered during the read
Program P-Flash Command
The Program P-Flash operation will program a previously erased phrase in the P-Flash memory using an
embedded algorithm.
CAUTION
A P-Flash phrase must be in the erased state before being programmed.
Cumulative programming of bits within a Flash phrase is not allowed.
Table 18-39. Program P-Flash Command FCCOB Requirements
CCOBIX[2:0]
000
1
FCCOB Parameters
0x06
Global address [22:16] to
identify P-Flash block
001
Global address [15:0] of phrase location to be programmed1
010
Word 0 program value
011
Word 1 program value
100
Word 2 program value
101
Word 3 program value
Global address [2:0] must be 000
Upon clearing CCIF to launch the Program P-Flash command, the Memory Controller will program the
data words to the supplied global address and will then proceed to verify the data words read back as
expected. The CCIF flag will set after the Program P-Flash operation has completed.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
543
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-40. Program P-Flash Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 101 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid global address [22:0] is supplied
Set if a misaligned phrase address is supplied (global address [2:0] != 000)
FSTAT
FPVIOL
18.4.2.6
Set if the global address [22:0] points to a protected area
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
Program Once Command
The Program Once command restricts programming to a reserved 64 byte field (8 phrases) in the
nonvolatile information register located in P-Flash block 0. The Program Once reserved field can be read
using the Read Once command as described in Section 18.4.2.4. The Program Once command must only
be issued once since the nonvolatile information register in P-Flash block 0 cannot be erased. The Program
Once command must not be executed from the Flash block containing the Program Once reserved field to
avoid code runaway.
Table 18-41. Program Once Command FCCOB Requirements
CCOBIX[2:0]
000
FCCOB Parameters
0x07
Not Required
001
Program Once phrase index (0x0000 - 0x0007)
010
Program Once word 0 value
011
Program Once word 1 value
100
Program Once word 2 value
101
Program Once word 3 value
Upon clearing CCIF to launch the Program Once command, the Memory Controller first verifies that the
selected phrase is erased. If erased, then the selected phrase will be programmed and then verified with
read back. The CCIF flag will remain clear, setting only after the Program Once operation has completed.
The reserved nonvolatile information register accessed by the Program Once command cannot be erased
and any attempt to program one of these phrases a second time will not be allowed. Valid phrase index
values for the Program Once command range from 0x0000 to 0x0007. During execution of the Program
Once command, any attempt to read addresses within P-Flash block 0 will return invalid data.
S12XS Family Reference Manual, Rev. 1.10
544
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
R,
Table 18-42. Program Once Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 101 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid phrase index is supplied
Set if the requested phrase has already been programmed1
FSTAT
FPVIOL
1
None
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
If a Program Once phrase is initially programmed to 0xFFFF_FFFF_FFFF_FFFF, the Program Once command will
be allowed to execute again on that same phrase.
18.4.2.7
Erase All Blocks Command
The Erase All Blocks operation will erase the entire P-Flash and D-Flash memory space.
Table 18-43. Erase All Blocks Command FCCOB Requirements
CCOBIX[2:0]
000
FCCOB Parameters
0x08
Not required
Upon clearing CCIF to launch the Erase All Blocks command, the Memory Controller will erase the entire
Flash memory space and verify that it is erased. If the Memory Controller verifies that the entire Flash
memory space was properly erased, security will be released. During the execution of this command
(CCIF=0) the user must not write to any Flash module register. The CCIF flag will set after the Erase All
Blocks operation has completed.
Table 18-44. Erase All Blocks Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 000 at command launch
ACCERR
Set if command not available in current mode (see Table 18-28)
FSTAT
18.4.2.8
FPVIOL
Set if any area of the P-Flash or D-Flash memory is protected
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
Erase Flash Block Command
The Erase Flash Block operation will erase all addresses in a P-Flash or D-Flash block.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
545
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-45. Erase Flash Block Command FCCOB Requirements
CCOBIX[2:0]
000
001
FCCOB Parameters
Global address [22:16] to
identify Flash block
0x09
Global address [15:0] in Flash block to be erased
Upon clearing CCIF to launch the Erase Flash Block command, the Memory Controller will erase the
selected Flash block and verify that it is erased. The CCIF flag will set after the Erase Flash Block
operation has completed.
Table 18-46. Erase Flash Block Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 001 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if the supplied P-Flash address is not phrase-aligned or if the D-Flash
address is not word-aligned
FSTAT
FPVIOL
18.4.2.9
Set if an invalid global address [22:16] is supplied
Set if an area of the selected Flash block is protected
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
Erase P-Flash Sector Command
The Erase P-Flash Sector operation will erase all addresses in a P-Flash sector.
Table 18-47. Erase P-Flash Sector Command FCCOB Requirements
CCOBIX[2:0]
000
001
FCCOB Parameters
0x0A
Global address [22:16] to identify
P-Flash block to be erased
Global address [15:0] anywhere within the sector to be erased.
Refer to Section 18.1.2.1 for the P-Flash sector size.
Upon clearing CCIF to launch the Erase P-Flash Sector command, the Memory Controller will erase the
selected Flash sector and then verify that it is erased. The CCIF flag will be set after the Erase P-Flash
Sector operation has completed.
S12XS Family Reference Manual, Rev. 1.10
546
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-48. Erase P-Flash Sector Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 001 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid global address [22:16] is supplied
Set if a misaligned phrase address is supplied (global address [2:0] != 000)
FSTAT
FPVIOL
Set if the selected P-Flash sector is protected
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
18.4.2.10 Unsecure Flash Command
The Unsecure Flash command will erase the entire P-Flash and D-Flash memory space and, if the erase is
successful, will release security.
Table 18-49. Unsecure Flash Command FCCOB Requirements
CCOBIX[2:0]
000
FCCOB Parameters
0x0B
Not required
Upon clearing CCIF to launch the Unsecure Flash command, the Memory Controller will erase the entire
P-Flash and D-Flash memory space and verify that it is erased. If the Memory Controller verifies that the
entire Flash memory space was properly erased, security will be released. If the erase verify is not
successful, the Unsecure Flash operation sets MGSTAT1 and terminates without changing the security
state. During the execution of this command (CCIF=0) the user must not write to any Flash module
register. The CCIF flag is set after the Unsecure Flash operation has completed.
Table 18-50. Unsecure Flash Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 000 at command launch
ACCERR
Set if command not available in current mode (see Table 18-28)
FSTAT
FPVIOL
Set if any area of the P-Flash or D-Flash memory is protected
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
18.4.2.11 Verify Backdoor Access Key Command
The Verify Backdoor Access Key command will only execute if it is enabled by the KEYEN bits in the
FSEC register (see Table 18-9). The Verify Backdoor Access Key command releases security if
user-supplied keys match those stored in the Flash security bytes of the Flash configuration field (see
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
547
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-3). The Verify Backdoor Access Key command must not be executed from the Flash block
containing the backdoor comparison key to avoid code runaway.
Table 18-51. Verify Backdoor Access Key Command FCCOB Requirements
CCOBIX[2:0]
FCCOB Parameters
000
0x0C
Not required
001
Key 0
010
Key 1
011
Key 2
100
Key 3
Upon clearing CCIF to launch the Verify Backdoor Access Key command, the Memory Controller will
check the FSEC KEYEN bits to verify that this command is enabled. If not enabled, the Memory
Controller sets the ACCERR bit in the FSTAT register and terminates. If the command is enabled, the
Memory Controller compares the key provided in FCCOB to the backdoor comparison key in the Flash
configuration field with Key 0 compared to 0x7F_FF00, etc. If the backdoor keys match, security will be
released. If the backdoor keys do not match, security is not released and all future attempts to execute the
Verify Backdoor Access Key command are aborted (set ACCERR) until a reset occurs. The CCIF flag is
set after the Verify Backdoor Access Key operation has completed.
Table 18-52. Verify Backdoor Access Key Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 100 at command launch
Set if an incorrect backdoor key is supplied
ACCERR
FSTAT
Set if backdoor key access has not been enabled (KEYEN[1:0] != 10, see
Section 18.3.2.2)
Set if the backdoor key has mismatched since the last reset
FPVIOL
None
MGSTAT1
None
MGSTAT0
None
18.4.2.12 Set User Margin Level Command
The Set User Margin Level command causes the Memory Controller to set the margin level for future read
operations of a specific P-Flash or D-Flash block.
Table 18-53. Set User Margin Level Command FCCOB Requirements
CCOBIX[2:0]
000
001
FCCOB Parameters
0x0D
Global address [22:16] to identify the
Flash block
Margin level setting
S12XS Family Reference Manual, Rev. 1.10
548
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Upon clearing CCIF to launch the Set User Margin Level command, the Memory Controller will set the
user margin level for the targeted block and then set the CCIF flag.
Valid margin level settings for the Set User Margin Level command are defined in Table 18-54.
Table 18-54. Valid Set User Margin Level Settings
CCOB
(CCOBIX=001)
Level Description
0x0000
Return to Normal Level
0x0001
User Margin-1 Level1
0x0002
User Margin-0 Level2
1
2
Read margin to the erased state
Read margin to the programmed state
Table 18-55. Set User Margin Level Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 001 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid global address [22:16] is supplied
FSTAT
Set if an invalid margin level setting is supplied
FPVIOL
None
MGSTAT1
None
MGSTAT0
None
NOTE
User margin levels can be used to check that Flash memory contents have
adequate margin for normal level read operations. If unexpected results are
encountered when checking Flash memory contents at user margin levels, a
potential loss of information has been detected.
18.4.2.13 Set Field Margin Level Command
The Set Field Margin Level command, valid in special modes only, causes the Memory Controller to set
the margin level specified for future read operations of a specific P-Flash or D-Flash block.
Table 18-56. Set Field Margin Level Command FCCOB Requirements
CCOBIX[2:0]
000
001
FCCOB Parameters
0x0E
Global address [22:16] to identify the Flash
block
Margin level setting
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
549
256 KByte Flash Module (S12XFTMR256K1V1)
Upon clearing CCIF to launch the Set Field Margin Level command, the Memory Controller will set the
field margin level for the targeted block and then set the CCIF flag. Valid margin level settings for the Set
Field Margin Level command are defined in Table 18-57.
Table 18-57. Valid Set Field Margin Level Settings
CCOB
(CCOBIX=001)
Level Description
0x0000
Return to Normal Level
0x0001
User Margin-1 Level1
0x0002
User Margin-0 Level2
0x0003
Field Margin-1 Level1
0x0004
Field Margin-0 Level2
1
2
Read margin to the erased state
Read margin to the programmed state
Table 18-58. Set Field Margin Level Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 001 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid global address [22:16] is supplied
FSTAT
Set if an invalid margin level setting is supplied
FPVIOL
None
MGSTAT1
None
MGSTAT0
None
CAUTION
Field margin levels must only be used during verify of the initial factory
programming.
NOTE
Field margin levels can be used to check that Flash memory contents have
adequate margin for data retention at the normal level setting. If unexpected
results are encountered when checking Flash memory contents at field
margin levels, the Flash memory contents should be erased and
reprogrammed.
18.4.2.14 Erase Verify D-Flash Section Command
The Erase Verify D-Flash Section command will verify that a section of code in the D-Flash is erased. The
Erase Verify D-Flash Section command defines the starting point of the data to be verified and the number
of words.
S12XS Family Reference Manual, Rev. 1.10
550
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-59. Erase Verify D-Flash Section Command FCCOB Requirements
CCOBIX[2:0]
FCCOB Parameters
000
0x10
Global address [22:16] to
identify the D-Flash block
001
Global address [15:0] of the first word to be verified
010
Number of words to be verified
Upon clearing CCIF to launch the Erase Verify D-Flash Section command, the Memory Controller will
verify the selected section of D-Flash memory is erased. The CCIF flag will set after the Erase Verify
D-Flash Section operation has completed.
Table 18-60. Erase Verify D-Flash Section Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 010 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid global address [22:0] is supplied
Set if a misaligned word address is supplied (global address [0] != 0)
FSTAT
Set if the requested section breaches the end of the D-Flash block
FPVIOL
None
MGSTAT1
Set if any errors have been encountered during the read
MGSTAT0
Set if any non-correctable errors have been encountered during the read
18.4.2.15 Program D-Flash Command
The Program D-Flash operation programs one to four previously erased words in the D-Flash block. The
Program D-Flash operation will confirm that the targeted location(s) were successfully programmed upon
completion.
CAUTION
A Flash word must be in the erased state before being programmed.
Cumulative programming of bits within a Flash word is not allowed.
Table 18-61. Program D-Flash Command FCCOB Requirements
CCOBIX[2:0]
000
FCCOB Parameters
0x11
Global address [22:16] to
identify the D-Flash block
001
Global address [15:0] of word to be programmed
010
Word 0 program value
011
Word 1 program value, if desired
100
Word 2 program value, if desired
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
551
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-61. Program D-Flash Command FCCOB Requirements
CCOBIX[2:0]
FCCOB Parameters
101
Word 3 program value, if desired
Upon clearing CCIF to launch the Program D-Flash command, the user-supplied words will be transferred
to the Memory Controller and be programmed if the area is unprotected. The CCOBIX index value at
Program D-Flash command launch determines how many words will be programmed in the D-Flash block.
The CCIF flag is set when the operation has completed.
Table 18-62. Program D-Flash Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] < 010 at command launch
Set if CCOBIX[2:0] > 101 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid global address [22:0] is supplied
Set if a misaligned word address is supplied (global address [0] != 0)
FSTAT
Set if the requested group of words breaches the end of the D-Flash block
FPVIOL
Set if the selected area of the D-Flash memory is protected
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
18.4.2.16 Erase D-Flash Sector Command
The Erase D-Flash Sector operation will erase all addresses in a sector of the D-Flash block.
Table 18-63. Erase D-Flash Sector Command FCCOB Requirements
CCOBIX[2:0]
000
001
FCCOB Parameters
0x12
Global address [22:16] to identify
D-Flash block
Global address [15:0] anywhere within the sector to be erased.
See Section 18.1.2.2 for D-Flash sector size.
Upon clearing CCIF to launch the Erase D-Flash Sector command, the Memory Controller will erase the
selected Flash sector and verify that it is erased. The CCIF flag will set after the Erase D-Flash Sector
operation has completed.
S12XS Family Reference Manual, Rev. 1.10
552
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
Table 18-64. Erase D-Flash Sector Command Error Handling
Register
Error Bit
Error Condition
Set if CCOBIX[2:0] != 001 at command launch
Set if command not available in current mode (see Table 18-28)
ACCERR
Set if an invalid global address [22:0] is supplied
Set if a misaligned word address is supplied (global address [0] != 0)
FSTAT
FPVIOL
18.4.3
Set if the selected area of the D-Flash memory is protected
MGSTAT1
Set if any errors have been encountered during the verify operation
MGSTAT0
Set if any non-correctable errors have been encountered during the verify
operation
Interrupts
The Flash module can generate an interrupt when a Flash command operation has completed or when a
Flash command operation has detected an ECC fault.
Table 18-65. Flash Interrupt Sources
Interrupt Source
Global (CCR)
Mask
Interrupt Flag
Local Enable
CCIF
(FSTAT register)
CCIE
(FCNFG register)
I Bit
ECC Double Bit Fault on Flash Read
DFDIF
(FERSTAT register)
DFDIE
(FERCNFG register)
I Bit
ECC Single Bit Fault on Flash Read
SFDIF
(FERSTAT register)
SFDIE
(FERCNFG register)
I Bit
Flash Command Complete
NOTE
Vector addresses and their relative interrupt priority are determined at the
MCU level.
18.4.3.1
Description of Flash Interrupt Operation
The Flash module uses the CCIF flag in combination with the CCIE interrupt enable bit to generate the
Flash command interrupt request. The Flash module uses the DFDIF and SFDIF flags in combination with
the DFDIE and SFDIE interrupt enable bits to generate the Flash error interrupt request. For a detailed
description of the register bits involved, refer to Section 18.3.2.5, “Flash Configuration Register
(FCNFG)”, Section 18.3.2.6, “Flash Error Configuration Register (FERCNFG)”, Section 18.3.2.7, “Flash
Status Register (FSTAT)”, and Section 18.3.2.8, “Flash Error Status Register (FERSTAT)”.
The logic used for generating the Flash module interrupts is shown in Figure 18-27.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
553
256 KByte Flash Module (S12XFTMR256K1V1)
Flash Command Interrupt Request
CCIE
CCIF
DFDIE
DFDIF
Flash Error Interrupt Request
SFDIE
SFDIF
Figure 18-27. Flash Module Interrupts Implementation
18.4.4
Wait Mode
The Flash module is not affected if the MCU enters wait mode. The Flash module can recover the MCU
from wait via the CCIF interrupt (see Section 18.4.3, “Interrupts”).
18.4.5
Stop Mode
If a Flash command is active (CCIF = 0) when the MCU requests stop mode, the current Flash operation
will be completed before the CPU is allowed to enter stop mode.
18.5
Security
The Flash module provides security information to the MCU. The Flash security state is defined by the
SEC bits of the FSEC register (see Table 18-10). During reset, the Flash module initializes the FSEC
register using data read from the security byte of the Flash configuration field at global address
0x7F_FF0F.
The security state out of reset can be permanently changed by programming the security byte of the Flash
configuration field. This assumes that you are starting from a mode where the necessary P-Flash erase and
program commands are available and that the upper region of the P-Flash is unprotected. If the Flash
security byte is successfully programmed, its new value will take affect after the next MCU reset.
The following subsections describe these security-related subjects:
• Unsecuring the MCU using Backdoor Key Access
• Unsecuring the MCU in Special Single Chip Mode using BDM
• Mode and Security Effects on Flash Command Availability
18.5.1
Unsecuring the MCU using Backdoor Key Access
The MCU may be unsecured by using the backdoor key access feature which requires knowledge of the
contents of the backdoor keys (four 16-bit words programmed at addresses 0x7F_FF00–0x7F_FF07). If
the KEYEN[1:0] bits are in the enabled state (see Section 18.3.2.2), the Verify Backdoor Access Key
command (see Section 18.4.2.11) allows the user to present four prospective keys for comparison to the
S12XS Family Reference Manual, Rev. 1.10
554
Freescale Semiconductor
256 KByte Flash Module (S12XFTMR256K1V1)
keys stored in the Flash memory via the Memory Controller. If the keys presented in the Verify Backdoor
Access Key command match the backdoor keys stored in the Flash memory, the SEC bits in the FSEC
register (see Table 18-10) will be changed to unsecure the MCU. Key values of 0x0000 and 0xFFFF are
not permitted as backdoor keys. While the Verify Backdoor Access Key command is active, P-Flash block
0 will not be available for read access and will return invalid data.
The user code stored in the P-Flash memory must have a method of receiving the backdoor keys from an
external stimulus. This external stimulus would typically be through one of the on-chip serial ports.
If the KEYEN[1:0] bits are in the enabled state (see Section 18.3.2.2), the MCU can be unsecured by the
backdoor key access sequence described below:
1. Follow the command sequence for the Verify Backdoor Access Key command as explained in
Section 18.4.2.11
2. If the Verify Backdoor Access Key command is successful, the MCU is unsecured and the
SEC[1:0] bits in the FSEC register are forced to the unsecure state of 10
The Verify Backdoor Access Key command is monitored by the Memory Controller and an illegal key will
prohibit future use of the Verify Backdoor Access Key command. A reset of the MCU is the only method
to re-enable the Verify Backdoor Access Key command.
After the backdoor keys have been correctly matched, the MCU will be unsecured. After the MCU is
unsecured, the sector containing the Flash security byte can be erased and the Flash security byte can be
reprogrammed to the unsecure state, if desired.
In the unsecure state, the user has full control of the contents of the backdoor keys by programming
addresses 0x7F_FF00–0x7F_FF07 in the Flash configuration field.
The security as defined in the Flash security byte (0x7F_FF0F) is not changed by using the Verify
Backdoor Access Key command sequence. The backdoor keys stored in addresses
0x7F_FF00–0x7F_FF07 are unaffected by the Verify Backdoor Access Key command sequence. After the
next reset of the MCU, the security state of the Flash module is determined by the Flash security byte
(0x7F_FF0F). The Verify Backdoor Access Key command sequence has no effect on the program and
erase protections defined in the Flash protection register, FPROT.
18.5.2
Unsecuring the MCU in Special Single Chip Mode using BDM
The MCU can be unsecured in special single chip mode by erasing the P-Flash and D-Flash memory by
one of the following methods:
• Reset the MCU into special single chip mode, delay while the erase test is performed by the BDM,
send BDM commands to disable protection in the P-Flash and D-Flash memory, and execute the
Erase All Blocks command write sequence to erase the P-Flash and D-Flash memory.
• Reset the MCU into special expanded wide mode, disable protection in the P-Flash and D-Flash
memory and run code from external memory to execute the Erase All Blocks command write
sequence to erase the P-Flash and D-Flash memory.
After the CCIF flag sets to indicate that the Erase All Blocks operation has completed, reset the MCU into
special single chip mode. The BDM will execute the Erase Verify All Blocks command write sequence to
verify that the P-Flash and D-Flash memory is erased. If the P-Flash and D-Flash memory are verified as
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
555
256 KByte Flash Module (S12XFTMR256K1V1)
erased the MCU will be unsecured. All BDM commands will be enabled and the Flash security byte may
be programmed to the unsecure state by the following method:
• Send BDM commands to execute a ‘Program P-Flash’ command sequence to program the Flash
security byte to the unsecured state and reset the MCU.
18.5.3
Mode and Security Effects on Flash Command Availability
The availability of Flash module commands depends on the MCU operating mode and security state as
shown in Table 18-28.
18.6
Initialization
On each system reset the Flash module executes a reset sequence which establishes initial values for the
Flash Block Configuration Parameters, the FPROT and DFPROT protection registers, and the FOPT and
FSEC registers. The Flash module reverts to built-in default values that leave the module in a fully
protected and secured state if errors are encountered during execution of the reset sequence. If a double bit
fault is detected during the reset sequence, both MGSTAT bits in the FSTAT register will be set.
CCIF remains clear throughout the reset sequence. The Flash module holds off all CPU access for the
initial portion of the reset sequence. While Flash reads are possible when the hold is removed, writes to
the FCCOBIX, FCCOBHI, and FCCOBLO registers are ignored to prevent command activity while the
Memory Controller remains busy. Completion of the reset sequence is marked by setting CCIF high which
enables writes to the FCCOBIX, FCCOBHI, and FCCOBLO registers to launch any available Flash
command.
If a reset occurs while any Flash command is in progress, that command will be immediately aborted. The
state of the word being programmed or the sector/block being erased is not guaranteed.
S12XS Family Reference Manual, Rev. 1.10
556
Freescale Semiconductor
Chapter 19
128 KByte Flash Module (S12XFTMR128K1V1)
Table 19-1. Revision History
Revision
Number
Revision
Date
V01.04
03 Jan 2008
V01.05
19 Dec 2008
19.1/19-557
19.4.2.4/19-592
19.4.2.6/19-594
19.4.2.11/19-59
7
19.4.2.11/19-59
7
19.4.2.11/19-59
7
V01.06
25 Sep 2009
The following changes were made to clarify module behavior related to Flash
register access during reset sequence and while Flash commands are active:
19.3.2/19-564 - Add caution concerning register writes while command is active
19.3.2.1/19-566 - Writes to FCLKDIV are allowed during reset sequence while CCIF is clear
19.4.1.2/19-586 - Add caution concerning register writes while command is active
- Writes to FCCOBIX, FCCOBHI, FCCOBLO registers are ignored during
19.6/19-606
reset sequence
19.1
Sections
Affected
Description of Changes
- Cosmetic changes
- Clarify single bit fault correction for P-Flash phrase
- Add statement concerning code runaway when executing Read Once,
Program Once, and Verify Backdoor Access Key commands from Flash block
containing associated fields
- Relate Key 0 to associated Backdoor Comparison Key address
- Change “power down reset” to “reset” in Section 19.4.2.11
Introduction
The FTMR128K1 module implements the following:
• 128 Kbytes of P-Flash (Program Flash) memory
• 8 Kbytes of D-Flash (Data Flash) memory
The Flash memory is ideal for single-supply applications allowing for field reprogramming without
requiring external high voltage sources for program or erase operations. The Flash module includes a
memory controller that executes commands to modify Flash memory contents. The user interface to the
memory controller consists of the indexed Flash Common Command Object (FCCOB) register which is
written to with the command, global address, data, and any required command parameters. The memory
controller must complete the execution of a command before the FCCOB register can be written to with a
new command.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
557
Preliminary
CAUTION
A Flash word or phrase must be in the erased state before being
programmed. Cumulative programming of bits within a Flash word or
phrase is not allowed.
The Flash memory may be read as bytes, aligned words, or misaligned words. Read access time is one bus
cycle for bytes and aligned words, and two bus cycles for misaligned words. For Flash memory, an erased
bit reads 1 and a programmed bit reads 0.
It is not possible to read from a Flash block while any command is executing on that specific Flash block.
It is possible to read from a Flash block while a command is executing on a different Flash block.
Both P-Flash and D-Flash memories are implemented with Error Correction Codes (ECC) that can resolve
single bit faults and detect double bit faults. For P-Flash memory, the ECC implementation requires that
programming be done on an aligned 8 byte basis (a Flash phrase). Since P-Flash memory is always read
by phrase, only one single bit fault in the phrase containing the byte or word accessed will be corrected.
19.1.1
Glossary
Command Write Sequence — An MCU instruction sequence to execute built-in algorithms (including
program and erase) on the Flash memory.
D-Flash Memory — The D-Flash memory constitutes the nonvolatile memory store for data.
D-Flash Sector — The D-Flash sector is the smallest portion of the D-Flash memory that can be erased.
The D-Flash sector consists of four 64 byte rows for a total of 256 bytes.
NVM Command Mode — An NVM mode using the CPU to setup the FCCOB register to pass parameters
required for Flash command execution.
Phrase — An aligned group of four 16-bit words within the P-Flash memory. Each phrase includes eight
ECC bits for single bit fault correction and double bit fault detection within the phrase.
P-Flash Memory — The P-Flash memory constitutes the main nonvolatile memory store for applications.
P-Flash Sector — The P-Flash sector is the smallest portion of the P-Flash memory that can be erased.
Each P-Flash sector contains 1024 bytes.
Program IFR — Nonvolatile information register located in the P-Flash block that contains the Device
ID, Version ID, and the Program Once field. The Program IFR is visible in the global memory map by
setting the PGMIFRON bit in the MMCCTL1 register.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
558
Preliminary
128 KByte Flash Module (S12XFTMR128K1V1)
19.1.2
19.1.2.1
•
•
•
•
•
•
•
•
•
•
D-Flash Features
8 Kbytes of D-Flash memory composed of one 8 Kbyte Flash block divided into 32 sectors of 256
bytes
Single bit fault correction and double bit fault detection within a word during read operations
Automated program and erase algorithm with verify and generation of ECC parity bits
Fast sector erase and word program operation
Protection scheme to prevent accidental program or erase of D-Flash memory
Ability to program up to four words in a burst sequence
19.1.2.3
•
•
•
P-Flash Features
128 Kbytes of P-Flash memory composed of one 128 Kbyte Flash block divided into 128 sectors
of 1024 bytes
Single bit fault correction and double bit fault detection within a 64-bit phrase during read
operations
Automated program and erase algorithm with verify and generation of ECC parity bits
Fast sector erase and phrase program operation
Flexible protection scheme to prevent accidental program or erase of P-Flash memory
19.1.2.2
•
Features
Other Flash Module Features
No external high-voltage power supply required for Flash memory program and erase operations
Interrupt generation on Flash command completion and Flash error detection
Security mechanism to prevent unauthorized access to the Flash memory
19.1.3
Block Diagram
The block diagram of the Flash module is shown in Figure 19-1.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
559
128 KByte Flash Module (S12XFTMR128K1V1)
Flash
Interface
Command
Interrupt
Request
16bit
internal
bus
Registers
Error
Interrupt
Request
P-Flash
16Kx72
sector 0
sector 1
Protection
sector 127
Security
Oscillator
Clock (XTAL)
CPU
Clock
Divider FCLK
Memory
Controller
Scratch RAM
384x16bits
D-Flash
4Kx22
sector 0
sector 1
sector 31
Figure 19-1. FTMR128K1 Block Diagram
19.2
External Signal Description
The Flash module contains no signals that connect off-chip.
19.3
Memory Map and Registers
This section describes the memory map and registers for the Flash module. Read data from unimplemented
memory space in the Flash module is undefined. Write access to unimplemented or reserved memory space
in the Flash module will be ignored by the Flash module.
S12XS Family Reference Manual, Rev. 1.10
560
Freescale Semiconductor
128 KByte Flash Module (S12XFTMR128K1V1)
19.3.1
Module Memory Map
The S12X architecture places the P-Flash memory between global addresses 0x7E_0000 and 0x7F_FFFF
as shown in Table 19-2. The P-Flash memory map is shown in Figure 19-2.
Table 19-2. P-Flash Memory Addressing
Global Address
Size
(Bytes)
0x7E_0000 – 0x7F_FFFF
128 K
Description
P-Flash Block 0
Contains Flash Configuration Field
(see Table 19-3)
The FPROT register, described in Section 19.3.2.9, can be set to protect regions in the Flash memory from
accidental program or erase. Three separate memory regions, one growing upward from global address
0x7F_8000 in the Flash memory (called the lower region), one growing downward from global address
0x7F_FFFF in the Flash memory (called the higher region), and the remaining addresses in the Flash
memory, can be activated for protection. The Flash memory addresses covered by these protectable regions
are shown in the P-Flash memory map. The higher address region is mainly targeted to hold the boot loader
code since it covers the vector space. Default protection settings as well as security information that allows
the MCU to restrict access to the Flash module are stored in the Flash configuration field as described in
Table 19-3.
Table 19-3. Flash Configuration Field1
Global Address
Size
(Bytes)
0x7F_FF00 – 0x7F_FF07
8
Backdoor Comparison Key
Refer to Section 19.4.2.11, “Verify Backdoor Access Key Command,” and
Section 19.5.1, “Unsecuring the MCU using Backdoor Key Access”
0x7F_FF08 – 0x7F_FF0B2
4
Reserved
0x7F_FF0C2
1
P-Flash Protection byte.
Refer to Section 19.3.2.9, “P-Flash Protection Register (FPROT)”
0x7F_FF0D2
1
D-Flash Protection byte.
Refer to Section 19.3.2.10, “D-Flash Protection Register (DFPROT)”
0x7F_FF0E2
1
Flash Nonvolatile byte
Refer to Section 19.3.2.15, “Flash Option Register (FOPT)”
0x7F_FF0F2
1
Flash Security byte
Refer to Section 19.3.2.2, “Flash Security Register (FSEC)”
1
2
Description
Older versions may have swapped protection byte addresses
0x7FF08 - 0x7F_FF0F form a Flash phrase and must be programmed in a single command write sequence. Each byte in
the 0x7F_FF08 - 0x7F_FF0B reserved field should be programmed to 0xFF.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
561
128 KByte Flash Module (S12XFTMR128K1V1)
P-Flash START = 0x7E_0000
Flash Protected/Unprotected Region
96 Kbytes
0x7F_8000
0x7F_8400
0x7F_8800
0x7F_9000
Flash Protected/Unprotected Lower Region
1, 2, 4, 8 Kbytes
0x7F_A000
Flash Protected/Unprotected Region
8 Kbytes (up to 29 Kbytes)
0x7F_C000
0x7F_E000
Flash Protected/Unprotected Higher Region
2, 4, 8, 16 Kbytes
0x7F_F000
0x7F_F800
P-Flash END = 0x7F_FFFF
Flash Configuration Field
16 bytes (0x7F_FF00 - 0x7F_FF0F)
Figure 19-2. P-Flash Memory Map
S12XS Family Reference Manual, Rev. 1.10
562
Freescale Semiconductor
128 KByte Flash Module (S12XFTMR128K1V1)
Table 19-4. Program IFR Fields
Global Address
(PGMIFRON)
Size
(Bytes)
0x40_0000 – 0x40_0007
8
Device ID
0x40_0008 – 0x40_00E7
224
Reserved
0x40_00E8 – 0x40_00E9
2
Version ID
0x40_00EA – 0x40_00FF
22
Reserved
0x40_0100 – 0x40_013F
64
Program Once Field
Refer to Section 19.4.2.6, “Program Once Command”
0x40_0140 – 0x40_01FF
192
Reserved
Field Description
Table 19-5. D-Flash and Memory Controller Resource Fields
Global Address
Size
(Bytes)
0x10_0000 – 0x10_1FFF
8,192
0x10_2000 – 0x11_FFFF
122,880
0x12_0000 – 0x12_007F
128
0x12_0080 – 0x12_0FFF
3,968
Reserved
0x12_1000 – 0x12_1FFF
4,096
Reserved
0x12_2000 – 0x12_3CFF
7,242
Reserved
0x12_3D00 – 0x12_3FFF
768
0x12_4000 – 0x12_E7FF
43,008
Reserved
0x12_E800 – 0x12_FFFF
6,144
Reserved
0x13_0000 – 0x13_FFFF
65,536
Reserved
1
Description
D-Flash Memory
Reserved
D-Flash Nonvolatile Information Register (DFIFRON1 = 1)
Memory Controller Scratch RAM (MGRAMON1 = 1)
MMCCTL1 register bit
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
563
128 KByte Flash Module (S12XFTMR128K1V1)
D-Flash START = 0x10_0000
D-Flash Memory
8 Kbytes
D-Flash END = 0x10_1FFF
0x12_0000
D-Flash Nonvolatile Information Register (DFIFRON)
128 bytes
0x12_1000
0x12_2000
Memory Controller Scratch RAM (MGRAMON)
768 bytes
0x12_4000
0x12_E800
0x12_FFFF
Figure 19-3. D-Flash and Memory Controller Resource Memory Map
19.3.2
Register Descriptions
The Flash module contains a set of 20 control and status registers located between Flash module base +
0x0000 and 0x0013. A summary of the Flash module registers is given in Figure 19-4 with detailed
descriptions in the following subsections.
CAUTION
Writes to any Flash register must be avoided while a Flash command is
active (CCIF=0) to prevent corruption of Flash register contents and
Memory Controller behavior.
Address
& Name
0x0000
FCLKDIV
0x0001
FSEC
7
R
6
5
4
3
2
1
0
FDIV6
FDIV5
FDIV4
FDIV3
FDIV2
FDIV1
FDIV0
KEYEN0
RNV5
RNV4
RNV3
RNV2
SEC1
SEC0
FDIVLD
W
R
KEYEN1
W
Figure 19-4. FTMR128K1 Register Summary
S12XS Family Reference Manual, Rev. 1.10
564
Freescale Semiconductor
128 KByte Flash Module (S12XFTMR128K1V1)
Address
& Name
0x0002
FCCOBIX
0x0003
FECCRIX
0x0004
FCNFG
0x0005
FERCNFG
0x0006
FSTAT
0x0007
FERSTAT
0x0008
FPROT
0x0009
DFPROT
0x000A
FCCOBHI
0x000B
FCCOBLO
0x000C
FRSV0
0x000D
FRSV1
0x000E
FECCRHI
0x000F
FECCRLO
R
7
6
5
4
3
0
0
0
0
0
2
1
0
CCOBIX2
CCOBIX1
CCOBIX0
ECCRIX2
ECCRIX1
ECCRIX0
FDFD
FSFD
DFDIE
SFDIE
MGSTAT1
MGSTAT0
DFDIF
SFDIF
W
R
0
0
0
0
0
W
R
0
0
CCIE
0
0
IGNSF
W
R
0
W
R
0
CCIF
ACCERR
FPVIOL
0
0
MGBUSY
RSVD
0
0
W
R
0
0
W
R
RNV6
FPOPEN
FPHDIS
FPHS1
FPHS0
FPLDIS
FPLS1
FPLS0
DPS4
DPS3
DPS2
DPS1
DPS0
W
R
0
0
DPOPEN
W
R
CCOB15
CCOB14
CCOB13
CCOB12
CCOB11
CCOB10
CCOB9
CCOB8
CCOB7
CCOB6
CCOB5
CCOB4
CCOB3
CCOB2
CCOB1
CCOB0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ECCR15
ECCR14
ECCR13
ECCR12
ECCR11
ECCR10
ECCR9
ECCR8
ECCR7
ECCR6
ECCR5
ECCR4
ECCR3
ECCR2
ECCR1
ECCR0
W
R
W
R
W
R
W
R
W
R
W
Figure 19-4. FTMR128K1 Register Summary (continued)
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
565
128 KByte Flash Module (S12XFTMR128K1V1)
Address
& Name
0x0010
FOPT
0x0011
FRSV2
0x0012
FRSV3
0x0013
FRSV4
R
7
6
5
4
3
2
1
0
NV7
NV6
NV5
NV4
NV3
NV2
NV1
NV0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
R
W
R
W
R
W
= Unimplemented or Reserved
Figure 19-4. FTMR128K1 Register Summary (continued)
19.3.2.1
Flash Clock Divider Register (FCLKDIV)
The FCLKDIV register is used to control timed events in program and erase algorithms.
Offset Module Base + 0x0000
7
R
6
5
4
3
2
1
0
0
0
0
FDIVLD
FDIV[6:0]
W
Reset
0
0
0
0
0
= Unimplemented or Reserved
Figure 19-5. Flash Clock Divider Register (FCLKDIV)
All bits in the FCLKDIV register are readable, bits 6–0 are write once and bit 7 is not writable.
Table 19-6. FCLKDIV Field Descriptions
Field
7
FDIVLD
6–0
FDIV[6:0]
Description
Clock Divider Loaded
0 FCLKDIV register has not been written
1 FCLKDIV register has been written since the last reset
Clock Divider Bits — FDIV[6:0] must be set to effectively divide OSCCLK down to generate an internal Flash
clock, FCLK, with a target frequency of 1 MHz for use by the Flash module to control timed events during program
and erase algorithms. Table 19-7 shows recommended values for FDIV[6:0] based on OSCCLK frequency.
Please refer to Section 19.4.1, “Flash Command Operations,” for more information.
S12XS Family Reference Manual, Rev. 1.10
566
Freescale Semiconductor
128 KByte Flash Module (S12XFTMR128K1V1)
CAUTION
The FCLKDIV register should never be written while a Flash command is
executing (CCIF=0). The FCLKDIV register is writable during the Flash
reset sequence even though CCIF is clear.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
567
128 KByte Flash Module (S12XFTMR128K1V1)
Table 19-7. FDIV vs OSCCLK Frequency
OSCCLK Frequency
(MHz)
1
2
MIN1
MAX
1.60
2.10
2.40
FDIV[6:0]
2
OSCCLK Frequency
(MHz)
FDIV[6:0]
MIN1
2
MAX
0x01
33.60
34.65
0x20
3.15
0x02
34.65
35.70
0x21
3.20
4.20
0x03
35.70
36.75
0x22
4.20
5.25
0x04
36.75
37.80
0x23
5.25
6.30
0x05
37.80
38.85
0x24
6.30
7.35
0x06
38.85
39.90
0x25
7.35
8.40
0x07
39.90
40.95
0x26
8.40
9.45
0x08
40.95
42.00
0x27
9.45
10.50
0x09
42.00
43.05
0x28
10.50
11.55
0x0A
43.05
44.10
0x29
11.55
12.60
0x0B
44.10
45.15
0x2A
12.60
13.65
0x0C
45.15
46.20
0x2B
13.65
14.70
0x0D
46.20
47.25
0x2C
14.70
15.75
0x0E
47.25
48.30
0x2D
15.75
16.80
0x0F
48.30
49.35
0x2E
16.80
17.85
0x10
49.35
50.40
0x2F
17.85
18.90
0x11
18.90
19.95
0x12
19.95
21.00
0x13
21.00
22.05
0x14
22.05
23.10
0x15
23.10
24.15
0x16
24.15
25.20
0x17
25.20
26.25
0x18
26.25
27.30
0x19
27.30
28.35
0x1A
28.35
29.40
0x1B
29.40
30.45
0x1C
30.45
31.50
0x1D
31.50
32.55
0x1E
32.55
33.60
0x1F
FDIV shown generates an FCLK frequency of >0.8 MHz
FDIV shown generates an FCLK frequency of 1.05 MHz
S12XS Family Reference Manual, Rev. 1.10
568
Freescale Semiconductor
128 KByte Flash Module (S12XFTMR128K1V1)
19.3.2.2
Flash Security Register (FSEC)
The FSEC register holds all bits associated with the security of the MCU and Flash module.
Offset Module Base + 0x0001
7
R
6
5
4
KEYEN[1:0]
3
2
1
RNV[5:2]
0
SEC[1:0]
W
Reset
F
F
F
F
F
F
F
F
= Unimplemented or Reserved
Figure 19-6. Flash Security Register (FSEC)
All bits in the FSEC register are readable but not writable.
During the reset sequence, the FSEC register is loaded with the contents of the Flash security byte in the
Flash configuration field at global address 0x7F_FF0F located in P-Flash memory (see Table 19-3) as
indicated by reset condition F in Figure 19-6. If a double bit fault is detected while reading the P-Flash
phrase containing the Flash security byte during the reset sequence, all bits in the FSEC register will be
set to leave the Flash module in a secured state with backdoor key access disabled.
Table 19-8. FSEC Field Descriptions
Field
Description
7–6
Backdoor Key Security Enable Bits — The KEYEN[1:0] bits define the enabling of backdoor key access to the
KEYEN[1:0] Flash module as shown in Table 19-9.
5–2
RNV[5:2}
Reserved Nonvolatile Bits — The RNV bits should remain in the erased state for future enhancements.
1–0
SEC[1:0]
Flash Security Bits — The SEC[1:0] bits define the security state of the MCU as shown in Table 19-10. If the
Flash module is unsecured using backdoor key access, the SEC bits are forced to 10.
Table 19-9. Flash KEYEN States
1
KEYEN[1:0]
Status of Backdoor Key Access
00
DISABLED
01
DISABLED1
10
ENABLED
11
DISABLED
Preferred KEYEN state to disable backdoor key access.
Table 19-10. Flash Security States
SEC[1:0]
Status of Security
00
SECURED
01
SECURED1
10
UNSECURED
11
SECURED
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
569
128 KByte Flash Module (S12XFTMR128K1V1)
1
Preferred SEC state to set MCU to secured state.
The security function in the Flash module is described in Section 19.5.
19.3.2.3
Flash CCOB Index Register (FCCOBIX)
The FCCOBIX register is used to index the FCCOB register for Flash memory operations.
Offset Module Base + 0x0002
R
7
6
5
4
3
0
0
0
0
0
2
1
0
CCOBIX[2:0]
W
Reset
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 19-7. FCCOB Index Register (FCCOBIX)
CCOBIX bits are readable and writable while remaining bits read 0 and are not writable.
Table 19-11. FCCOBIX Field Descriptions
Field
Description
2–0
CCOBIX[1:0]
Common Command Register Index— The CCOBIX bits are used to select which word of the FCCOB register
array is being read or written to. See Section 19.3.2.11, “Flash Common Command Object Register (FCCOB),”
for more details.
19.3.2.4
Flash ECCR Index Register (FECCRIX)
The FECCRIX register is used to index the FECCR register for ECC fault reporting.
Offset Module Base + 0x0003
R
7
6
5
4
3
0
0
0
0
0
2
1
0
ECCRIX[2:0]
W
Reset
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 19-8. FECCR Index Register (FECCRIX)
ECCRIX bits are readable and writable while remaining bits read 0 and are not writable.
Table 19-12. FECCRIX Field Descriptions
Field
Description
2-0
ECC Error Register Index— The ECCRIX bits are used to select which word of the FECCR register array is
ECCRIX[2:0] being read. See Section 19.3.2.14, “Flash ECC Error Results Register (FECCR),” for more details.
S12XS Family Reference Manual, Rev. 1.10
570
Freescale Semiconductor
128 KByte Flash Module (S12XFTMR128K1V1)
19.3.2.5
Flash Configuration Register (FCNFG)
The FCNFG register enables the Flash command complete interrupt and forces ECC faults on Flash array
read access from the CPU or XGATE.
Offset Module Base + 0x0004
7
R
6
5
0
0
CCIE
4
3
2
0
0
IGNSF
1
0
FDFD
FSFD
0
0
W
Reset
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 19-9. Flash Configuration Register (FCNFG)
CCIE, IGNSF, FDFD, and FSFD bits are readable and writable while remaining bits read 0 and are not
writable.
Table 19-13. FCNFG Field Descriptions
Field
Description
7
CCIE
Command Complete Interrupt Enable — The CCIE bit controls interrupt generation when a Flash command
has completed.
0 Command complete interrupt disabled
1 An interrupt will be requested whenever the CCIF flag in the FSTAT register is set (see Section 19.3.2.7)
4
IGNSF
Ignore Single Bit Fault — The IGNSF controls single bit fault reporting in the FERSTAT register (see
Section 19.3.2.8).
0 All single bit faults detected during array reads are reported
1 Single bit faults detected during array reads are not reported and the single bit fault interrupt will not be
generated
1
FDFD
Force Double Bit Fault Detect — The FDFD bit allows the user to simulate a double bit fault during Flash array
read operations and check the associated interrupt routine. The FDFD bit is cleared by writing a 0 to FDFD. The
FECCR registers will not be updated during the Flash array read operation with FDFD set unless an actual
double bit fault is detected.
0 Flash array read operations will set the DFDIF flag in the FERSTAT register only if a double bit fault is detected
1 Any Flash array read operation will force the DFDIF flag in the FERSTAT register to be set (see
Section 19.3.2.7) and an interrupt will be generated as long as the DFDIE interrupt enable in the FERCNFG
register is set (see Section 19.3.2.6)
0
FSFD
Force Single Bit Fault Detect — The FSFD bit allows the user to simulate a single bit fault during Flash array
read operations and check the associated interrupt routine. The FSFD bit is cleared by writing a 0 to FSFD. The
FECCR registers will not be updated during the Flash array read operation with FSFD set unless an actual single
bit fault is detected.
0 Flash array read operations will set the SFDIF flag in the FERSTAT register only if a single bit fault is detected
1 Flash array read operation will force the SFDIF flag in the FERSTAT register to be set (see Section 19.3.2.7)
and an interrupt will be generated as long as the SFDIE interrupt enable in the FERCNFG register is set (see
Section 19.3.2.6)
19.3.2.6
Flash Error Configuration Register (FERCNFG)
The FERCNFG register enables the Flash error interrupts for the FERSTAT flags.
S12XS Family Reference Manual, Rev. 1.10
Freescale Semiconductor
571
128 KByte Flash Module (S12XFTMR128K1V1)
Offset Module Base + 0x0005
7
6
R
5
4
3
2
1
0
DFDIE
SFDIE
0
0
0
W
Reset
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 19-10. Flash Error Configuration Register (FERCNFG)
All assigned bits in the FERCNFG register are readable and writable.
Table 19-14. FERCNFG Field Descriptions
Field
Description
1
DFDIE
Double Bit Fault Detect Interrupt Enable — The DFDIE bit controls interrupt generation when a double bit fault
is detected during a Flash block read operation.
0 DFDIF interrupt disabled
1 An interrupt will be requested whenever the DFDIF flag is set (see Section 19.3.2.8)
0
SFDIE
Single Bit Fault Detect Interrupt Enable — The SFDIE bit controls interrupt generation when a single bit fault
is detected during a Flash block read operation.
0 SFDIF interrupt disabled whenever the SFDIF flag is set (see Section 19.3.2.8)
1 An interrupt will be requested whenever the SFDIF flag is set (see Section 19.3.2.8)
19.3.2.7
Flash Status Register (FSTAT)
The FSTAT register reports the operational status of the Flash module.
Offset Module Base + 0x0006
7
R
6
5
4
ACCERR
FPVIOL
0
0
0
CCIF
3
2
MGBUSY
RSVD
0
0
1
0
MGSTAT[1:0]
W
Reset
1
0
01
01
= Unimplemented or Reserved
Figure 19-11. Flash Status Register (FSTAT)
1
Reset value can deviate from the value shown if a double bit fault is detected during the reset