Freescale MC312XDP512J1VFUR Hcs12x microcontroller Datasheet

MC9S12XDP512
Data Sheet
Covers
S12XD, S12XB & S12XA Families
HCS12X
Microcontrollers
MC9S12XDP512RMV2
Rev. 2.21
October 2009
freescale.com
MC9S12XDP512RMV2 Data Sheet
MC9S12XDP512RMV2
Rev. 2.21
October 2009
To provide the most up-to-date information, the revision of our documents on the World Wide Web will be
the most current. Your printed copy may be an earlier revision. To verify you have the latest information
available, refer to:
http://freescale.com/
A full list of family members and options is included in the appendices.
Read page 29 first to understand the maskset specific chapters of this document
This document contains information for all constituent modules, with the exception of the S12X CPU. For
S12X CPU information please refer to the CPU S12X Reference Manual.
Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc.
This product incorporates SuperFlash® technology licensed from SST.
© Freescale Semiconductor, Inc., 2008. All rights reserved.
MC9S12XDP512 Data Sheet, Rev. 2.21
4
Freescale Semiconductor
Revision History
Date
Revision
Level
April, 2005
02.07
New Book
May, 2005
02.08
Minor corrections
May, 2005
02.09
removed ESD Machine Model from electrical characteristics
added thermal characteristics
added more details to run current measurement configurations
VDDA supply voltage range 3.15V - 3.6V fot ATD Operating Characteristics
I/O Chararcteristics for alll pins except EXTAL, XTAL ....
corrected VREG electrical spec
IDD wait max 95mA
May 2005
02.10
Improvements to NVM reliabity spec, added part numbers
July 2005
02.11
Added ROM parts to App.
October 2005
02.12
Single Souce S12XD Fam. Document, New Memory Map Figures,
May 2006
2.13
SPI electricals updated
Voltage Regulator electricals updated
Added Partnumbers and 1L15Y maskset
Updated App. E 6SCI’s on 112 pin DT/P512 and 3 SPI’s on all D256 parts
June 2006
2.14
Data Sheet covers S12XD/B & A Family
Included differnt pull device specification for differnt masksets
July 2006
2.15
Minor Corrections and Improvments
June 2007
2.16
Added 2M42E and 1M84E masksets
July 2007
2.17
Modified Appendix
April 2008
2.18
Better explanation of ATD0/1 for S12XD-Family see page 1305
S12XB256 ATD specification changed see Appendix E.6
added M23S maskset
August 2008
2.19
Corrected XGRAMSIZE of S12XD256 on page 44
Corrected 17.4.2.4 XGATE Memory Map Scheme
Corrected 18.4.2.4 XGATE Memory Map Scheme
September
2009
2.20
Corrected Table E-6 , 30K flash memory available for XGATE on B256
October 2009
2.21
Corrected Footnote in Appendix E3 regarding Shared XGATE/CPU area
Description
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
5
MC9S12XDP512 Data Sheet, Rev. 2.21
6
Freescale Semiconductor
Section Number
Title
Page
Chapter 1
Device Overview MC9S12XD-Family . . . . . . . . . . . . . . . . . . . . 31
Chapter 2
Clocks and Reset Generator (S12CRGV6) . . . . . . . . . . . . . . . . 79
Chapter 3
Pierce Oscillator (S12XOSCLCPV1) . . . . . . . . . . . . . . . . . . . . 119
Chapter 4
Analog-to-Digital Converter (ATD10B16CV4)
Block Description125
Chapter 5
Analog-to-Digital Converter (S12ATD10B8CV3) . . . . . . . . . . 159
Chapter 6
XGATE (S12XGATEV2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Chapter 7
Enhanced Capture Timer (S12ECT16B8CV2) . . . . . . . . . . . . 309
Chapter 8
Pulse-Width Modulator (S12PWM8B8CV1) . . . . . . . . . . . . . . 363
Chapter 9
Inter-Integrated Circuit (IICV2) Block Description. . . . . . . . . 395
Chapter 10
419
Freescale’s Scalable Controller Area Network (S12MSCANV3).
Chapter 11
Serial Communication Interface (S12SCIV5) . . . . . . . . . . . . . 477
Chapter 12
Serial Peripheral Interface (S12SPIV4) . . . . . . . . . . . . . . . . . . 515
Chapter 13
Periodic Interrupt Timer (S12PIT24B4CV1) . . . . . . . . . . . . . . 541
Chapter 14
Voltage Regulator (S12VREG3V3V5) . . . . . . . . . . . . . . . . . . . 555
Chapter 15
Background Debug Module (S12XBDMV2) . . . . . . . . . . . . . . 569
Chapter 16
Interrupt (S12XINTV1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
Chapter 17
Memory Mapping Control (S12XMMCV2) . . . . . . . . . . . . . . . . 613
Chapter 18
Memory Mapping Control (S12XMMCV3) . . . . . . . . . . . . . . . 651
Chapter 19
S12X Debug (S12XDBGV2) Module . . . . . . . . . . . . . . . . . . . . 693
Chapter 20
S12X Debug (S12XDBGV3) Module . . . . . . . . . . . . . . . . . . . . 745
Chapter 21
External Bus Interface (S12XEBIV2) . . . . . . . . . . . . . . . . . . . 787
Chapter 22
DP512 Port Integration Module (S12XDP512PIMV2) . . . . . . . 807
Chapter 23
DQ256 Port Integration Module (S12XDQ256PIMV2) . . . . . . 901
Chapter 24
DG128 Port Integration Module (S12XDG128PIMV2) . . . . . . 975
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
5
Section Number
Title
Page
Chapter 25
2 Kbyte EEPROM Module (S12XEETX2KV1) . . . . . . . . . . . . 1039
Chapter 26
4 Kbyte EEPROM Module (S12XEETX4KV2) . . . . . . . . . . . . 1073
Chapter 27
512 Kbyte Flash Module (S12XFTX512K4V2). . . . . . . . . . . . 1107
Chapter 28
256 Kbyte Flash Module (S12XFTX256K2V1). . . . . . . . . . . . 1149
Chapter 29
128 Kbyte Flash Module (S12XFTX128K1V1). . . . . . . . . . . . 1191
Chapter 30
Security (S12X9SECV2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1231
Appendix A Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1239
Appendix B Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1290
Appendix C Recommended PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . . 1294
Appendix D Using L15Y Silicon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1299
Appendix E Derivative Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1300
Appendix F Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1308
Appendix G Detailed Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1309
MC9S12XDP512 Data Sheet, Rev. 2.21
6
Freescale Semiconductor
Section Number
Title
Page
Chapter 1Device Overview MC9S12XD-Family
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
1.1.1 MC9S12XD/B/A Family Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
1.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
1.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
1.1.4 Device Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
1.1.5 Part ID Assignments & Maskset Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
1.2.1 Device Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
1.2.2 Signal Properties Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
1.2.3 Detailed Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
1.2.4 Power Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
System Clock Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Chip Configuration Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
1.5.1 User Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
1.5.2 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
1.5.3 Freeze Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Resets and Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
1.6.1 Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
1.6.2 Effects of Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
COP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
ATD0 External Trigger Input Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
ATD1 External Trigger Input Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Chapter 2
Clocks and Reset Generator (S12CRGV6)
2.1
2.2
2.3
2.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
2.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
2.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
2.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
2.2.1 VDDPLL and VSSPLL — Operating and Ground Voltage Pins . . . . . . . . . . . . . . . . . . . . . 82
2.2.2 XFC — External Loop Filter Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
2.2.3 RESET — Reset Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
2.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
2.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
2.4.1 Functional Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
2.4.2 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
2.4.3 Low Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
9
Section Number
2.5
2.6
Title
Page
Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
2.5.1 Description of Reset Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
2.5.2 Clock Monitor Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.5.3 Computer Operating Properly Watchdog (COP) Reset . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.5.4 Power On Reset, Low Voltage Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
2.6.1 Real Time Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
2.6.2 PLL Lock Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
2.6.3 Self Clock Mode Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Chapter 3
Pierce Oscillator (S12XOSCLCPV1)
3.1
3.2
3.3
3.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
3.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
3.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
3.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
3.2.1 VDDPLL and VSSPLL — Operating and Ground Voltage Pins . . . . . . . . . . . . . . . . . . . . 120
3.2.2 EXTAL and XTAL — Input and Output Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
3.2.3 XCLKS — Input Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
3.4.1 Gain Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
3.4.2 Clock Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
3.4.3 Wait Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
3.4.4 Stop Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Chapter 4
Analog-to-Digital Converter (ATD10B16CV4)
Block Description
4.1
4.2
4.3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
4.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
4.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
4.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
4.2.1 ANx (x = 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) — Analog Input Channel x Pins
127
4.2.2 ETRIG3, ETRIG2, ETRIG1, ETRIG0 — External Trigger Pins . . . . . . . . . . . . . . . . . 127
4.2.3 VRH, VRL — High Reference Voltage Pin, Low Reference Voltage Pin . . . . . . . . . . . . 127
4.2.4 VDDA, VSSA — Analog Circuitry Power Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . 127
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
MC9S12XDP512 Data Sheet, Rev. 2.21
10
Freescale Semiconductor
Section Number
4.4
4.5
4.6
Title
Page
4.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
4.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
4.4.1 Analog Sub-block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
4.4.2 Digital Sub-Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
4.4.3 Operation in Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Chapter 5Analog-to-Digital Converter (S12ATD10B8CV3)
5.1
5.2
5.3
5.4
5.5
5.6
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
5.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
5.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
5.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
5.2.1 ANx (x = 7, 6, 5, 4, 3, 2, 1, 0) — Analog Input Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
5.2.2 ETRIG3, ETRIG2, ETRIG1, and ETRIG0 — External Trigger Pins . . . . . . . . . . . . . . 160
5.2.3 VRH and VRL — High and Low Reference Voltage Pins . . . . . . . . . . . . . . . . . . . . . . . . 160
5.2.4 VDDA and VSSA — Power Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
5.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
5.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
5.4.1 Analog Sub-Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
5.4.2 Digital Sub-Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Chapter 6
XGATE (S12XGATEV2)
6.1
6.2
6.3
6.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
6.1.1 Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
6.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
6.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
6.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
6.3.1 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
6.4.1 XGATE RISC Core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
6.4.2 Programmer’s Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
6.4.3 Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
11
Section Number
6.5
6.6
6.7
6.8
6.9
Title
Page
6.4.4 Semaphores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
6.4.5 Software Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
6.5.1 Incoming Interrupt Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
6.5.2 Outgoing Interrupt Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
6.6.1 Debug Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
6.6.2 Entering Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
6.6.3 Leaving Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Instruction Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
6.8.1 Addressing Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
6.8.2 Instruction Summary and Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
6.8.3 Cycle Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
6.8.4 Thread Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
6.8.5 Instruction Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
6.8.6 Instruction Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Initialization and Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
6.9.1 Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
6.9.2 Code Example (Transmit "Hello World!" on SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
Chapter 7
Enhanced Capture Timer (S12ECT16B8CV2)
7.1
7.2
7.3
7.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
7.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
7.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
7.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
7.2.1 IOC7 — Input Capture and Output Compare Channel 7 . . . . . . . . . . . . . . . . . . . . . . . . 311
7.2.2 IOC6 — Input Capture and Output Compare Channel 6 . . . . . . . . . . . . . . . . . . . . . . . . 311
7.2.3 IOC5 — Input Capture and Output Compare Channel 5 . . . . . . . . . . . . . . . . . . . . . . . . 311
7.2.4 IOC4 — Input Capture and Output Compare Channel 4 . . . . . . . . . . . . . . . . . . . . . . . . 311
7.2.5 IOC3 — Input Capture and Output Compare Channel 3 . . . . . . . . . . . . . . . . . . . . . . . . 311
7.2.6 IOC2 — Input Capture and Output Compare Channel 2 . . . . . . . . . . . . . . . . . . . . . . . . 311
7.2.7 IOC1 — Input Capture and Output Compare Channel 1 . . . . . . . . . . . . . . . . . . . . . . . . 311
7.2.8 IOC0 — Input Capture and Output Compare Channel 0 . . . . . . . . . . . . . . . . . . . . . . . . 311
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
7.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
7.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
7.4.1 Enhanced Capture Timer Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
7.4.2 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
MC9S12XDP512 Data Sheet, Rev. 2.21
12
Freescale Semiconductor
Section Number
Title
Page
7.4.3 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
Chapter 8
Pulse-Width Modulator (S12PWM8B8CV1)
8.1
8.2
8.3
8.4
8.5
8.6
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
8.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
8.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
8.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
8.2.1 PWM7 — PWM Channel 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
8.2.2 PWM6 — PWM Channel 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
8.2.3 PWM5 — PWM Channel 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
8.2.4 PWM4 — PWM Channel 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
8.2.5 PWM3 — PWM Channel 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
8.2.6 PWM3 — PWM Channel 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
8.2.7 PWM3 — PWM Channel 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
8.2.8 PWM3 — PWM Channel 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
8.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
8.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380
8.4.1 PWM Clock Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380
8.4.2 PWM Channel Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384
Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
Chapter 9
Inter-Integrated Circuit (IICV2) Block Description
9.1
9.2
9.3
9.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
9.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
9.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
9.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
9.2.1 IIC_SCL — Serial Clock Line Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
9.2.2 IIC_SDA — Serial Data Line Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
9.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
9.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
9.4.1 I-Bus Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
9.4.2 Operation in Run Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
9.4.3 Operation in Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
13
Section Number
9.5
9.6
9.7
Title
Page
9.4.4 Operation in Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
9.7.1 IIC Programming Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Chapter 10
Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
10.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
10.1.2 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
10.1.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
10.1.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
10.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
10.2.1 RXCAN — CAN Receiver Input Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
10.2.2 TXCAN — CAN Transmitter Output Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
10.2.3 CAN System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
10.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
10.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
10.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
10.3.3 Programmer’s Model of Message Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445
10.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
10.4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
10.4.2 Message Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
10.4.3 Identifier Acceptance Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460
10.4.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
10.4.5 Low-Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
10.4.6 Reset Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472
10.4.7 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472
10.5 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
10.5.1 MSCAN initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
10.5.2 Bus-Off Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
Chapter 11
Serial Communication Interface (S12SCIV5)
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
11.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
11.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
11.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
11.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
11.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
11.2.1 TXD — Transmit Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
MC9S12XDP512 Data Sheet, Rev. 2.21
14
Freescale Semiconductor
Section Number
Title
Page
11.2.2 RXD — Receive Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
11.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
11.3.1 Module Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
11.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
11.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
11.4.1 Infrared Interface Submodule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
11.4.2 LIN Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
11.4.3 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495
11.4.4 Baud Rate Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496
11.4.5 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497
11.4.6 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
11.4.7 Single-Wire Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
11.4.8 Loop Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
11.5 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
11.5.1 Reset Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
11.5.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
11.5.3 Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512
11.5.4 Recovery from Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
11.5.5 Recovery from Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
Chapter 12
Serial Peripheral Interface (S12SPIV4)
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
12.1.1 Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
12.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
12.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
12.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516
12.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
12.2.1 MOSI — Master Out/Slave In Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
12.2.2 MISO — Master In/Slave Out Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
12.2.3 SS — Slave Select Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518
12.2.4 SCK — Serial Clock Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518
12.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518
12.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518
12.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519
12.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
12.4.1 Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529
12.4.2 Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530
12.4.3 Transmission Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
12.4.4 SPI Baud Rate Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
12.4.5 Special Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
12.4.6 Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
15
Section Number
Title
Page
12.4.7 Low Power Mode Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537
Chapter 13
Periodic Interrupt Timer (S12PIT24B4CV1)
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
13.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
13.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
13.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
13.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
13.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
13.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
13.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551
13.4.1 Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551
13.4.2 Interrupt Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552
13.4.3 Hardware Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
13.5 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
13.5.1 Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
13.5.2 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
13.5.3 Flag Clearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
Chapter 14
Voltage Regulator (S12VREG3V3V5)
14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555
14.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555
14.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555
14.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556
14.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557
14.2.1 VDDR — Regulator Power Input Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557
14.2.2 VDDA, VSSA — Regulator Reference Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . 557
14.2.3 VDD, VSS — Regulator Output1 (Core Logic) Pins . . . . . . . . . . . . . . . . . . . . . . . . . . 557
14.2.4 VDDPLL, VSSPLL — Regulator Output2 (PLL) Pins . . . . . . . . . . . . . . . . . . . . . . . . . 558
14.2.5 VREGEN — Optional Regulator Enable Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558
14.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558
14.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558
14.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559
14.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564
14.4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564
14.4.2 Regulator Core (REG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564
14.4.3 Low-Voltage Detect (LVD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565
14.4.4 Power-On Reset (POR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565
14.4.5 Low-Voltage Reset (LVR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565
14.4.6 Regulator Control (CTRL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565
MC9S12XDP512 Data Sheet, Rev. 2.21
16
Freescale Semiconductor
Section Number
Title
Page
14.4.7 Autonomous Periodical Interrupt (API) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565
14.4.8 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
14.4.9 Description of Reset Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
14.4.10Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
Chapter 15
Background Debug Module (S12XBDMV2)
15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569
15.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569
15.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570
15.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 571
15.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572
15.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572
15.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572
15.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573
15.3.3 Family ID Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577
15.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
15.4.1 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
15.4.2 Enabling and Activating BDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
15.4.3 BDM Hardware Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
15.4.4 Standard BDM Firmware Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580
15.4.5 BDM Command Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 582
15.4.6 BDM Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584
15.4.7 Serial Interface Hardware Handshake Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586
15.4.8 Hardware Handshake Abort Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588
15.4.9 SYNC — Request Timed Reference Pulse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 591
15.4.10Instruction Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592
15.4.11Serial Communication Time Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 593
Chapter 16
Interrupt (S12XINTV1)
16.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
16.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596
16.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596
16.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596
16.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 598
16.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599
16.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599
16.3.1 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600
16.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
16.4.1 S12X Exception Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
16.4.2 Interrupt Prioritization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
17
Section Number
Title
Page
16.4.3 XGATE Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608
16.4.4 Priority Decoders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608
16.4.5 Reset Exception Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609
16.4.6 Exception Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609
16.5 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
16.5.1 Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
16.5.2 Interrupt Nesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
16.5.3 Wake Up from Stop or Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611
Chapter 17
Memory Mapping Control (S12XMMCV2)
17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
17.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
17.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
17.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 614
17.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 614
17.3 Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616
17.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616
17.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617
17.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630
17.4.1 MCU Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630
17.4.2 Memory Map Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
17.4.3 Chip Access Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 640
17.4.4 Chip Bus Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 642
17.4.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643
17.5 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643
17.5.1 CALL and RTC Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643
17.5.2 Port Replacement Registers (PRRs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644
17.5.3 On-Chip ROM Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
Chapter 18
Memory Mapping Control (S12XMMCV3)
18.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651
18.1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652
18.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652
18.1.3 S12X Memory Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653
18.1.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653
18.1.5 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654
18.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654
18.3 Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
18.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
18.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657
MC9S12XDP512 Data Sheet, Rev. 2.21
18
Freescale Semiconductor
Section Number
Title
Page
18.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 671
18.4.1 MCU Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 671
18.4.2 Memory Map Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 672
18.4.3 Chip Access Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 681
18.4.4 Chip Bus Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 683
18.4.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 684
18.5 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 684
18.5.1 CALL and RTC Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 684
18.5.2 Port Replacement Registers (PRRs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 685
18.5.3 On-Chip ROM Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 687
Chapter 19
S12X Debug (S12XDBGV2) Module
19.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693
19.1.1 Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693
19.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694
19.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694
19.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695
19.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695
19.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697
19.3.1 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697
19.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714
19.4.1 DBG Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714
19.4.2 Comparator Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 715
19.4.3 Trigger Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
19.4.4 State Sequence Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 720
19.4.5 Trace Buffer Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 721
19.4.6 Tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 728
19.4.7 Breakpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 729
Chapter 20
S12X Debug (S12XDBGV3) Module
20.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745
20.1.1 Glossary Of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745
20.1.2 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745
20.1.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 746
20.1.4 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 746
20.1.5 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 747
20.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 747
20.3 Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 748
20.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 748
20.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 749
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
19
Section Number
Title
Page
20.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 768
20.4.1 S12XDBG Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 768
20.4.2 Comparator Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 769
20.4.3 Trigger Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 772
20.4.4 State Sequence Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 774
20.4.5 Trace Buffer Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
20.4.6 Tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782
20.4.7 Breakpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
Chapter 21
External Bus Interface (S12XEBIV2)
21.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
21.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
21.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
21.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
21.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
21.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
21.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
21.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
21.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
21.4.1 Operating Modes and External Bus Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
21.4.2 Internal Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795
21.4.3 Accesses to Port Replacement Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
21.4.4 Stretched External Bus Accesses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
21.4.5 Data Select and Data Direction Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
21.4.6 Low-Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
21.5 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
21.5.1 Normal Expanded Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
21.5.2 Emulation Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
Chapter 22
DP512 Port Integration Module (S12XDP512PIMV2)
22.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807
22.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 808
22.1.2 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 808
22.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 810
22.2.1 Signal Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 810
22.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 817
22.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 817
22.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 820
22.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 881
22.4.1 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 881
MC9S12XDP512 Data Sheet, Rev. 2.21
20
Freescale Semiconductor
Section Number
Title
Page
22.4.2 Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 883
22.4.3 Pin Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 887
22.4.4 Expanded Bus Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 888
22.4.5 Low-Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 889
22.5 Initialization and Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 889
Chapter 23
DQ256 Port Integration Module (S12XDQ256PIMV2)
Chapter 23Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
23.0.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
23.0.2 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
Figure 23-1.External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
23.0.3 Signal Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
Table 23-1.Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 910
23.0.4 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 910
23.0.5 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 913
Table 23-66.Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 962
23.0.6 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 963
23.0.7 Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 965
23.0.8 Pin Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 968
23.0.9 Expanded Bus Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 969
23.0.10Low-Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971
23.0.10.3Initialization and Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971
Chapter 24
DG128 Port Integration Module (S12XDG128PIMV2)
Chapter 24Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 975
24.0.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 975
24.0.2 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 976
Figure 24-1.External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 978
24.0.3 Signal Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 978
Table 24-1.Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 983
24.0.4 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 983
24.0.5 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 985
Table 24-59.Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1028
24.0.6 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1029
24.0.7 Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1031
24.0.8 Pin Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1033
24.0.9 Low-Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1034
24.0.9.3Initialization and Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1035
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
21
Section Number
Title
Page
Chapter 25
2 Kbyte EEPROM Module (S12XEETX2KV1)
25.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1039
25.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1039
25.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1039
25.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1039
25.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1040
25.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1040
25.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1040
25.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1040
25.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1043
25.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1051
25.4.1 EEPROM Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1051
25.4.2 EEPROM Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1054
25.4.3 Illegal EEPROM Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1068
25.5 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1069
25.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1069
25.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1069
25.5.3 Background Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1069
25.6 EEPROM Module Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1069
25.6.1 Unsecuring the MCU in Special Single Chip Mode using BDM . . . . . . . . . . . . . . . . 1070
25.7 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1070
25.7.1 EEPROM Reset Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1070
25.7.2 Reset While EEPROM Command Active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1070
25.8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1070
25.8.1 Description of EEPROM Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1071
Chapter 26
4 Kbyte EEPROM Module (S12XEETX4KV2)
26.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1073
26.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1073
26.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1073
26.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1073
26.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1074
26.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1074
26.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1074
26.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1074
26.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1078
26.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1086
26.4.1 EEPROM Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1086
26.4.2 EEPROM Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1089
26.4.3 Illegal EEPROM Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1103
MC9S12XDP512 Data Sheet, Rev. 2.21
22
Freescale Semiconductor
Section Number
Title
Page
26.5 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1104
26.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1104
26.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1104
26.5.3 Background Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1104
26.6 EEPROM Module Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1104
26.6.1 Unsecuring the MCU in Special Single Chip Mode using BDM . . . . . . . . . . . . . . . . 1105
26.7 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1105
26.7.1 EEPROM Reset Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1105
26.7.2 Reset While EEPROM Command Active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1105
26.8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1105
26.8.1 Description of EEPROM Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1106
Chapter 27
512 Kbyte Flash Module (S12XFTX512K4V2)
27.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1107
27.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1107
27.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1107
27.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1108
27.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1108
27.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1109
27.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1110
27.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1110
27.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1113
27.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1126
27.4.1 Flash Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1126
27.4.2 Flash Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1129
27.4.3 Illegal Flash Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1144
27.5 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1145
27.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1145
27.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1145
27.5.3 Background Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1145
27.6 Flash Module Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1145
27.6.1 Unsecuring the MCU using Backdoor Key Access . . . . . . . . . . . . . . . . . . . . . . . . . . . 1146
27.6.2 Unsecuring the MCU in Special Single Chip Mode using BDM . . . . . . . . . . . . . . . . 1147
27.7 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1147
27.7.1 Flash Reset Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1147
27.7.2 Reset While Flash Command Active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1147
27.8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1147
27.8.1 Description of Flash Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1148
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
23
Section Number
Title
Page
Chapter 28
256 Kbyte Flash Module (S12XFTX256K2V1)
28.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1149
28.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1149
28.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1149
28.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1150
28.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1150
28.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1150
28.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1151
28.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1151
28.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1153
28.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1166
28.4.1 Flash Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1166
28.4.2 Flash Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1169
28.4.3 Illegal Flash Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1185
28.5 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1186
28.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1186
28.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1186
28.5.3 Background Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1186
28.6 Flash Module Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1186
28.6.1 Unsecuring the MCU using Backdoor Key Access . . . . . . . . . . . . . . . . . . . . . . . . . . . 1187
28.6.2 Unsecuring the MCU in Special Single Chip Mode using BDM . . . . . . . . . . . . . . . . 1188
28.7 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1188
28.7.1 Flash Reset Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1188
28.7.2 Reset While Flash Command Active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1188
28.8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1188
28.8.1 Description of Flash Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1189
Chapter 29
128 Kbyte Flash Module (S12XFTX128K1V1)
29.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1191
29.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1191
29.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1191
29.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1192
29.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1192
29.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1192
29.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1193
29.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1193
29.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1195
29.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1208
29.4.1 Flash Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1208
29.4.2 Flash Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1211
MC9S12XDP512 Data Sheet, Rev. 2.21
24
Freescale Semiconductor
Section Number
29.5
29.6
29.7
29.8
Title
Page
29.4.3 Illegal Flash Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1226
Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1227
29.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1227
29.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1227
29.5.3 Background Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1227
Flash Module Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1227
29.6.1 Unsecuring the MCU using Backdoor Key Access . . . . . . . . . . . . . . . . . . . . . . . . . . . 1227
29.6.2 Unsecuring the MCU in Special Single Chip Mode using BDM . . . . . . . . . . . . . . . . 1229
Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1229
29.7.1 Flash Reset Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1229
29.7.2 Reset While Flash Command Active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1229
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1229
29.8.1 Description of Flash Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1230
Chapter 30
Security (S12X9SECV2)
30.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1231
30.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1231
30.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1232
30.1.3 Securing the Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1232
30.1.4 Operation of the Secured Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1233
30.1.5 Unsecuring the Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1235
30.1.6 Reprogramming the Security Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1236
30.1.7 Complete Memory Erase (Special Modes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1236
Appendix A
Electrical Characteristics
A.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1239
A.1.1 Parameter Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1239
A.1.2 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1239
A.1.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1240
A.1.4 Current Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1240
A.1.5 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1241
A.1.6 ESD Protection and Latch-up Immunity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1241
A.1.7 Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1243
A.1.8 Power Dissipation and Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1244
A.1.9 I/O Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1246
A.1.10 Supply Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1249
A.2 ATD Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1253
A.2.1 ATD Operating Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1253
A.2.2 Factors Influencing Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1254
A.2.3 ATD Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1256
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
25
Section Number
Title
Page
A.3 NVM, Flash, and EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1259
A.3.1 NVM Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1259
A.3.2 NVM Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1262
A.4 Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1264
A.4.1 Chip Power-up and Voltage Drops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1265
A.4.2 Output Loads. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1265
A.5 Reset, Oscillator, and PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1267
A.5.1 Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1267
A.5.2 Oscillator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1268
A.5.3 Phase Locked Loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1270
A.6 MSCAN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1273
A.7 SPI Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1274
A.7.1 Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1274
A.7.2 Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1276
A.8 External Bus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1279
A.8.1 Normal Expanded Mode (External Wait Feature Disabled). . . . . . . . . . . . . . . . . . . . . 1279
A.8.2 Normal Expanded Mode (External Wait Feature Enabled) . . . . . . . . . . . . . . . . . . . . . 1281
A.8.3 Emulation Single-Chip Mode (Without Wait States) . . . . . . . . . . . . . . . . . . . . . . . . . . 1284
A.8.4 Emulation Expanded Mode (With Optional Access Stretching) . . . . . . . . . . . . . . . . . 1286
A.8.5 External Tag Trigger Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1289
Appendix B
Package Information
B.1 144-Pin LQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1291
B.2 112-Pin LQFP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1292
B.3 80-Pin QFP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1293
Appendix C
Recommended PCB Layout
Appendix D
Using L15Y Silicon
Appendix E
Derivative Differences
E.1
E.2
E.3
E.4
E.5
E.6
Memory Sizes and Package Options S12XD - Family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1300
Memory Sizes and Package Options S12XA & S12XB Family. . . . . . . . . . . . . . . . . . . . . . . . . 1302
MC9S12XD-Family Flash Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1303
MC9S12XD/A/B -Family SRAM & EEPROM Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 1304
Peripheral Sets S12XD - Family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1305
Peripheral Sets S12XA & S12XB - Family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1306
MC9S12XDP512 Data Sheet, Rev. 2.21
26
Freescale Semiconductor
Section Number
E.7
Title
Page
Pinout explanations: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1307
Appendix F
Ordering Information
Appendix G
Detailed Register Map
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
27
Section Number
Title
Page
MC9S12XDP512 Data Sheet, Rev. 2.21
28
Freescale Semiconductor
NOTE
This documentation covers all devices in the S12XD, S12XB and S12XA
families. A full list of these devices and their features can be found in the
following chapters:
• E.1 Memory Sizes and Package Options S12XD - Family
• E.2 Memory Sizes and Package Options S12XA & S12XB Family
• E.5 Peripheral Sets S12XD - Family
• E.6 Peripheral Sets S12XA & S12XB - Family
• Table 1-6 Partnames, Masksets and assigned PartID’s
This document includes different sections for S12XDPIM, S1XMMC,
S12XDBG, S12XEETX and S12XFTX because the different masksets of
the S12XD, S12XB and S12XA families include differnt configurations or
versions of the modules or have different memory sizes. Table 0-1 shows the
maskset specific chapters in this documentation.
Table 0-1. Maskset Specific Documentation
Chapters in this Documentation
L15Y
(512k
Flash)
M84E
(256K
Flash)
Chapter 21 External Bus Interface (S12XEBIV2) 787
✓
✓
Chapter 17 Memory Mapping Control (S12XMMCV2) 613
✓
Chapter 18 Memory Mapping Control (S12XMMCV3) 649
Chapter 19 Debug (S12XDBGV2) 691
✓
✓
✓
✓
✓
Chapter 20 S12X Debug (S12XDBGV3) Module 743
Chapter 22 DP512 Port Integration Module (S12XDP512PIMV2) 805
M42E
(128K
Flash)
✓
✓
Chapter 23 DQ256 Port Integration Module (S12XDQ256PIMV2) 899
Chapter 24 DG128 Port Integration Module (S12XDG128PIMV2) 973
✓
Chapter 25 2 Kbyte EEPROM Module (S12XEETX2KV1) 1037
✓
Chapter 26 4 Kbyte EEPROM Module (S12XEETX4KV2) 1071
✓
Chapter 27 512 Kbyte Flash Module (S12XFTX512K4V2) 1105
✓
✓
✓
Chapter 28 256 Kbyte Flash Module (S12XFTX256K2V1) 1147
✓
Chapter 29 128 Kbyte Flash Module (S12XFTX128K1V1) 1189
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV3) 157
✓
✓
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
29
Chapter 1 Device Overview MC9S12XD-Family describes pinouts, detailed pin description , interrupts
and register map of the cover part MC9S12XDP512 (maskset L15Y). For availability of the modules on
other members of the S12XA, S12XB and S12XD families please refer to Appendix E Derivative
Differences. For pinout explanations of the different parts refer to E.7 Pinout explanations:. For a list of
available partnames /masksets refer to Table 1-6.
MC9S12XDP512 Data Sheet, Rev. 2.21
30
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
Chapter 1 Device Overview MC9S12XD-Family
1.1
Introduction
The MC9S12XD family will retain the low cost, power consumption, EMC and code-size efficiency
advantages currently enjoyed by users of Freescale's existing 16-Bit MC9S12 MCU Family.
Based around an enhanced S12 core, the MC9S12XD family will deliver 2 to 5 times the performance of
a 25-MHz S12 whilst retaining a high degree of pin and code compatibility with the S12.
The MC9S12XD family introduces the performance boosting XGATE module. Using enhanced DMA
functionality, this parallel processing module offloads the CPU by providing high-speed data processing
and transfer between peripheral modules, RAM, Flash EEPROM and I/O ports. Providing up to 80 MIPS
of performance additional to the CPU, the XGATE can access all peripherals, Flash EEPROM and the
RAM block.
The MC9S12XD family is composed of standard on-chip peripherals including up to 512 Kbytes of Flash
EEPROM, 32 Kbytes of RAM, 4 Kbytes of EEPROM, six asynchronous serial communications interfaces
(SCI), three serial peripheral interfaces (SPI), an 8-channel IC/OC enhanced capture timer, an 8-channel,
10-bit analog-to-digital converter, a 16-channel, 10-bit analog-to-digital converter, an 8-channel
pulse-width modulator (PWM), five CAN 2.0 A, B software compatible modules (MSCAN12), two
inter-IC bus blocks, and a periodic interrupt timer. The MC9S12XD family has full 16-bit data paths
throughout.
The non-multiplexed expanded bus interface available on the 144-pin versions allows an easy interface to
external memories
The inclusion of a PLL circuit allows power consumption and performance to be adjusted to suit
operational requirements. System power consumption can be further improved with the new “fast exit from
stop mode” feature.
In addition to the I/O ports available in each module, up to 25 further I/O ports are available with interrupt
capability allowing wake-up from stop or wait mode.
Family members in 144-pin LQFP will be available with external bus interface and parts in 112-pin LQFP
or 80-pin QFP package without external bus interface. See Appendix E Derivative Differences for package
options.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
31
Chapter 1 Device Overview MC9S12XD-Family
1.1.1
MC9S12XD/B/A Family Features
This section lists the features which are available on
MC9S12XDP512RMV2. See Appendix E Derivative Differences for
availability of features and memory sizes on other family members.
•
•
•
•
•
•
•
HCS12X Core
— 16-bit HCS12X CPU
– Upward compatible with MC9S12 instruction set
– Interrupt stacking and programmer’s model identical to MC9S12
– Instruction queue
– Enhanced indexed addressing
– Enhanced instruction set
— EBI (external bus interface)
— MMC (module mapping control)
— INT (interrupt controller)
— DBG (debug module to monitor HCS12X CPU and XGATE bus activity)
— BDM (background debug mode)
XGATE (peripheral coprocessor)
— Parallel processing module off loads the CPU by providing high-speed data processing and
transfer
— Data transfer between Flash EEPROM, RAM, peripheral modules, and I/O ports
PIT (periodic interrupt timer)
— Four timers with independent time-out periods
— Time-out periods selectable between 1 and 224 bus clock cycles
CRG (clock and reset generator)
— Low noise/low power Pierce oscillator
— PLL
— COP watchdog
— Real time interrupt
— Clock monitor
— Fast wake-up from stop mode
Port H & Port J with interrupt functionality
— Digital filtering
— Programmable rising or falling edge trigger
Memory
— 512, 256 and 128-Kbyte Flash EEPROM
— 4 and 2-Kbyte EEPROM
— 32, 16 and 12-Kbyte RAM
One 16-channel and one 8-channel ADC (analog-to-digital converter)
MC9S12XDP512 Data Sheet, Rev. 2.21
32
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
•
•
•
•
•
•
— 10-bit resolution
— External and internal conversion trigger capabilityFiveFourTwo 1M bit per second,
CAN 2.0 A, B software compatible modules
— Five receive and three transmit buffers
— Flexible identifier filter programmable as 2 x 32 bit, 4 x 16 bit, or 8 x 8 bit
— Four separate interrupt channels for Rx, Tx, error, and wake-up
— Low-pass filter wake-up function
— Loop-back for self-test operation
ECT (enhanced capture timer)
— 16-bit main counter with 7-bit prescaler
— 8 programmable input capture or output compare channels
— Four 8-bit or two 16-bit pulse accumulators
8 PWM (pulse-width modulator) channels
— Programmable period and duty cycle
— 8-bit 8-channel or 16-bit 4-channel
— Separate control for each pulse width and duty cycle
— Center-aligned or left-aligned outputs
— Programmable clock select logic with a wide range of frequencies
— Fast emergency shutdown input
Serial interfaces
— SixFourTwo asynchronous serial communication interfaces (SCI) with additional LIN support
and selectable IrDA 1.4 return-to-zero-inverted (RZI) format with programmable pulse width
— ThreeTwo Synchronous Serial Peripheral Interfaces (SPI)
TwoOne IIC (Inter-IC bus) Modules
— Compatible with IIC bus standard
— Multi-master operation
— Software programmable for one of 256 different serial clock frequencies
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
— 3.3-V–5.5-V operation
— Low-voltage reset (LVR)
— Ultra low-power wake-up timer
144-pin LQFP, 112-pin LQFP, and 80-pin QFP packages
— I/O lines with 5-V input and drive capability
— Input threshold on external bus interface inputs switchable for 3.3-V or 5-V operation
— 5-V A/D converter inputs
— Operation at 80 MHz equivalent to 40-MHz bus speed
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
33
Chapter 1 Device Overview MC9S12XD-Family
•
1.1.2
Development support
— Single-wire background debug™ mode (BDM)
— Four on-chip hardware breakpoints
Modes of Operation
Normal expanded mode, Emulation of single-chip mode and Emulation of
expanded mode are ony available on family members with an external bus
interface in 144-pin LQFP. See Appendix E Derivative Differences for
package options.
User modes:
•
•
Normal and emulation operating modes
— Normal single-chip mode
— Normal expanded mode
— Emulation of single-chip mode
— Emulation of expanded mode
Special Operating Modes
— Special single-chip mode with active background debug mode
— Special test mode (Freescale use only)
Low-power modes:
• System stop modes
— Pseudo stop mode
— Full stop mode
• System wait mode
1.1.3
Block Diagram
Figure 1-1 shows a block diagram of theMC9S12X-Family. The block diagram shows all modules
available on cover part MC9S12XDP512RMV2. Availability of modules on other family members see
Appendix E Derivative Differences. Figure 1-2 shows blocks integrated on maskset M42E. The 16 channel
ATD Converter is routed to pins PAD00 - PAD15 on maskset M42E. See Chapter 4 Analog-to-Digital
Converter (ATD10B16CV4) Block Description 123.
MC9S12XDP512 Data Sheet, Rev. 2.21
34
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
SCI1
SPI0
DDRA
PTA
Timer
4-Channel
16-Bit with Prescaler
for Internal Timebases
Non-Multiplexed External Bus Interface (EBI)
DDRB
DDRC
DDRD
PTB
SCI3
RXD
TXD
Digital Supply 2.5 V
VDD1,2
VSS1,2
PLL Supply 2.5 V
VDDPLL
VSSPLL
Analog Supply 3-5 V
VDDA
VSSA
CAN1
CAN2
CAN3
CAN4
SCI2
IIC1
IIC0
PWM
I/O Supply 3-5 V
VDDX1,2
VSSX1,2
Voltage Regulator 3-5 V
VDDR1,2
VSSR1,2
SCI4
SCI5
RXD
TXD
RXD
TXD
SPI1
SPI2
MISO
MOSI
SCK
SS
RXCAN
TXCAN
RXCAN
TXCAN
RXCAN
TXCAN
RXCAN
TXCAN
RXCAN
TXCAN
RXD
TXD
SDA
SCL
SDA
SCL
PWM0
PWM1
PWM2
PWM3
PWM4
PWM5
PWM6
PWM7
MISO
MOSI
SCK
SS
MISO
MOSI
SCK
SS
KWJ0
KWJ1
KWJ2
KWJ4
KWJ5
KWJ6
KWJ7
KWP0
KWP1
KWP2
KWP3
KWP4
KWP5
KWP6
KWP7
KWH0
KWH1
KWH2
KWH3
KWH4
KWH5
KWH6
KWH7
DDRAD1 & AD1
PTT
VRH
VRL
VDDA
VSSA
PAD08
PAD09
PAD10
PAD11
PAD12
PAD13
PAD14
PAD15
PAD16
PAD17
PAD18
PAD19
PAD20
PAD21
PAD22
PAD23
PT0
PT1
PT2
PT3
PT4
PT5
PT6
PT7
PS0
PS1
PS2
PS3
PS4
PS5
PS6
PS7
PM0
PM1
PM2
PM3
PM4
PM5
PM6
PM7
PJ0 CS3
PJ1
PJ2 CS1
PJ4 CS0
PJ5 CS2
PJ6
PJ7
PP0
PP1
PP2
PP3
PP4
PP5
PP6
PP7
PH0
PH1
PH2
PH3
PH4
PH5
PH6
PH7
Signals shown in Bold-Italics are neither available on the 112-pin nor on the 80-pin oackage option
Signals shown in Bold are not available on the 80-pin package
SCI0
DDRT
Enhanced Capture
Timer
PTS
XIRQ
IRQ
R/W/WE
LSTRB/LDS/EROMCTL
ECLK
MODA/RE/TAGLO
MODB/TAGHI
ECLKX2/XCLKS
IQSTAT0
IQSTAT1
IQSTAT2
IQSTAT3
8-Bit PPAGE
ACC0
Allows 4-MByte
ACC1
Program space
ACC2
ROMCTL/EWAIT
XGATE
Peripheral Co-Processor
DDRS
Periodic Interrupt
COP Watchdog
Clock Monitor
Breakpoints
PTM
Enhanced Multilevel
Interrupt Module
DDRM
DDRE
DDRK
PTE
PTK
Clock
and Reset
Generation
Module
CAN0
PTC
UDS
ADDR16
ADDR17
ADDR18
ADDR19
ADDR20
ADDR21
ADDR22
EWAIT
ADDR15
ADDR14
ADDR13
ADDR12
ADDR11
ADDR10
ADDR9
ADDR8
ADDR7
ADDR6
ADDR5
ADDR4
ADDR3
ADDR2
ADDR1
ADDR0
DATA15
DATA14
DATA13
DATA12
DATA11
DATA10
DATA9
DATA8
DATA7
DATA6
DATA5
DATA4
DATA3
DATA2
DATA1
DATA0
PE0
PE1
PE2
PE3
PE4
PE5
PE6
PE7
PK0
PK1
PK2
PK3
PK4
PK5
PK6
PK7
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
PLL
PTD
VDDPLL
VSSPLL
EXTAL
XTAL
RESET
TEST
PTJ
CPU12X
XFC
DDRJ
Single-Wire
Background
Debug Module
BKGD
PTP
Voltage Regulator
AN8
AN9
AN10
AN11
AN12
AN13
AN14
AN15
AN16
AN17
AN18
AN19
AN20
AN21
AN22
AN23
IOC0
IOC1
IOC2
IOC3
IOC4
IOC5
IOC6
IOC7
RXD
TXD
RXD
TXD
DDRP
VREGEN
VDD1,2
VSS1,2
PAD00
PAD01
PAD02
PAD03
PAD04
PAD05
PAD06
PAD07
VRH
VRL
VDDA
VSSA
PTH
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7
4/2/1-Kbyte EEPROM
VDDR
VSSR
ATD1
DDRH
32/20/16/14/10/8/4-Kbyte RAM
VRH
VRL
VDDA
VSSA
Module to Port Routing
ATD0
DDRAD0 & AD0
512/384/256/128/64-Kbyte Flash
Figure 1-1. MC9S12XD-Family Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
35
Chapter 1 Device Overview MC9S12XD-Family
XGATE
Peripheral
Co-Processor
SCI1
CAN4
RXCAN
TXCAN
Digital Supply 2.5 V
VDD1,2
VSS1,2
Analog Supply 3-5 V
VDDA
VSSA
IIC0
PWM
I/O Supply 3-5 V
VDDX
VSSX
Voltage Regulator 3-5 V
VDDR
VSSR
PTAD1
PJ0
PJ1
DDRJ
PLL Supply 2.5 V
VDDPLL
VSSPLL
KWJ0
KWJ1
SPI1
SDA
SCL
PWM0
PWM1
PWM2
PWM3
PWM4
PWM5
PWM6
PWM7
MISO
MOSI
SCK
SS
KWJ6
KWJ7
KWP0
KWP1
KWP2
KWP3
KWP4
KWP5
KWP6
KWP7
KWH0
KWH1
KWH2
KWH3
KWH4
KWH5
KWH6
KWH7
PTJ
Timer
4-Channel
16-Bit with Prescaler
for Internal Timebases
MISO
MOSI
SCK
SS
RXCAN
CAN0
TXCAN
SPI0
PTP
8-Bit PPAGE
Allows 4-MByte
Program space
PTH
DDRK
DDRA
PTK
SCI0
DDRP
DDRE
PTE
Enhanced Capture
Timer
ECLK
PAD00
PAD01
PAD02
PAD03
PAD04
PAD05
PAD06
PAD07
PAD08
PAD09
PAD10
PAD11
PAD12
PAD13
PAD14
PAD15
PT0
PT1
PT2
PT3
PT4
PT5
PT6
PT7
PS0
PS1
PS2
PS3
PS4
PS5
PS6
PS7
PM0
PM1
PM2
PM3
PM4
PM5
PM6
PM7
PJ6
PJ7
PP0
PP1
PP2
PP3
PP4
PP5
PP6
PP7
PH0
PH1
PH2
PH3
PH4
PH5
PH6
PH7
Signals shown in Bold-Italics are neither available on the 112-pin nor on the 80-pin oackage option
Signals shown in Bold are not available on the 80-pin package
Periodic Interrupt
COP Watchdog
Clock Monitor
Breakpoints
PTT
Enhanced Multilevel
Interrupt Module
ECLKX2/XCLKS
DDRB
PK7
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
Clock
and Reset
Generation
Module
XIRQ
IRQ
PTA
PE0
PE1
PE2
PE3
PE4
PE5
PE6
PE7
PK0
PK1
PK2
PK3
PK4
PK5
PLL
PTB
VDDPLL
VSSPLL
EXTAL
XTAL
RESET
TEST
PTS
CPU12X
XFC
DDRH
Single-Wire
Background
Debug Module
BKGD
PTM
Voltage Regulator
Module to Port Routing
VREGEN
VDD1,2
VSS1,2
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7
AN8
AN9
AN10
AN11
AN12
AN13
AN14
AN15
IOC0
IOC1
IOC2
IOC3
IOC4
IOC5
IOC6
IOC7
RXD
TXD
RXD
TXD
DDRAD1
2-Kbyte EEPROM
VDDR
VSSR
VRH
VRL
VDDA
VSSA
VDDA
VSSA
DDRT
12 Kbyte RAM
VRH
VRL
DDRS
ATD1
DDRM
128-Kbyte Flash
Figure 1-2. Block Diagram Maskset M42E
MC9S12XDP512 Data Sheet, Rev. 2.21
36
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
1.1.4
Device Memory Map
Table 1-1shows the device register memory map of the MC9S12XDP512. Available modules on other
Family members please refer to Appendix E Derivative Differences
Unimplemented register space shown in Table 1-1 is not allocated to any module. Writing to these
locations have no effect. Read access to these locations returns zero. Figure 1-1 shows the global address
mapping for the parts listed in Table 1-2.
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
EBI (external bus interface)
2
0x0010–0x0017
MMC (memory map control)
8
0x0018–0x0019
Unimplemented
2
0x001A–0x001B
Device ID register
2
0x001C–0x001F
PIM (port integration module)
4
0x0020–0x002F
DBG (debug module)
16
0x0030–0x0031
MMC (memory map control)
2
0x0032–0x0033
PIM (port integration module)
2
0x0034–0x003F
CRG (clock and reset generator)
12
0x0040–0x007F
ECT (enhanced capture timer 16-bit 8-channel)s
64
0x0080–0x00AF
ATD1 (analog-to-digital converter 10-bit 16-channel)
48
0x00B0–0x00B7
IIC1 (inter IC bus)
8
0x00B8–0x00C7
Reserved
16
0x00B8–0x00BF
SCI2 (serial communications interface)
8
0x00C0–0x00C7
SCI3 (serial communications interface)
8
0x00C8–0x00CF
SCI0 (serial communications interface)
8
0x00D0–0x00D7
SCI1 (serial communications interface)
8
0x00D8–0x00DF
SPI0 (serial peripheral interface)
8
0x00E0–0x00E7
IIC0 (inter IC bus)
8
0x00E8–0x00EF
Unimplemented
8
0x00F0–0x00F7
SPI1 (serial peripheral interface)
8
0x00F8–0x013F
Reserved
8
0x00F8–0x00FF
SPI2 (serial peripheral interface)
8
0x0100–0x010F
Flash control register
16
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
37
Chapter 1 Device Overview MC9S12XD-Family
Table 1-1. Device Register Memory Map (continued)
Address
Module
Size
(Bytes)
0x0110–0x011B
EEPROM control register
12
0x011C–0x011F
MMC (memory map control)
4
0x0120–0x012F
INT (interrupt module)
16
0x0130–0x013F
Reserved
16
0x0130–0x0137
SCI4 (serial communications interface)
8
0x0138–0x013F
SCI5 (serial communications interface)
8
0x0140–0x017F
CAN0 (scalable CAN)
64
0x0180–0x01BF
CAN1 (scalable CAN)
64
0x0180–0x023F
Reserved
192
0x01C0–0x01FF
CAN2 (scalable CAN)
64
0x0200–0x023F
Reserved
64
0x0200–0x023F
CAN3 (scalable CAN)
64
0x0240–0x027F
PIM (port integration module)
64
0x0280–0x02BF
CAN4 (scalable CAN)
64
0x02C0–0x02DF
Reserved
32
0x02C0–0x02DF
ATD0 (analog-to-digital converter 10 bit 8-channel)
32
0x02E0–0x02EF
Unimplemented
16
0x02F0–0x02F7
Voltage regulator
8
0x02F8–0x02FF
Unimplemented
8
0x0300–0x0327
PWM (pulse-width modulator 8 channels)
40
0x0328–0x033F
Unimplemented
24
0x0340–0x0367
Periodic interrupt timer
40
0x0368–0x037F
Unimplemented
24
0x0380–0x03BF
XGATE
64
0x03C0–0x03FF
Unimplemented
64
0x0400–0x07FF
Unimplemented
1024
MC9S12XDP512 Data Sheet, Rev. 2.21
38
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
CPU and BDM
Local Memory Map
Global Memory Map
0x00_0000
0x00_07FF
2K REGISTERS
CS3
Unimplemented
RAM
0x0800
0x0C00
0x1000
RAM
2K REGISTERS
1K EEPROM window
EPAGE
0x0F_FFFF
1K EEPROM
4K RAM window
Unimplemented
EEPROM
RPAGE
CS2
0x0000
RAMSIZE
RAM_LOW
8K RAM
EEPROM_LOW
EEPROM
0x4000
0x13_FFFF
CS2
Unpaged
16K FLASH
EEPROMSIZE
0x2000
0x1F_FFFF
External
Space
CS1
0x8000
PPAGE
0x3F_FFFF
0xC000
CS0
16K FLASH window
Unimplemented
FLASH
Unpaged
16K FLASH
Reset Vectors
FLASH_LOW
FLASH
FLASHSIZE
0xFFFF
0x7F_FFFF
Figure 1-3. S12X CPU & BDM Global Address Mapping
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
39
Chapter 1 Device Overview MC9S12XD-Family
Table 1-2. Device Internal Resources (see Figure 1-3)
RAMSIZE/
RAM_LOW
EEPROMSIZE/
EEPROM_LOW
FLASHSIZE/
FLASH_LOW
9S12XDP512
32K
0x0F_8000
4K
0x13_F000
512K
0x78_0000
9S12XDT512
20K
0x0F_B000
4K
0x13_F000
512K
0x78_0000
9S12XA512
32K
0x0F_8000
4K
0x13_F000
512K
0x78_0000
9S12XDG128
12K
0x0F_D000
2K
0x13_F800
128K
7E_0000
3S12XDG128
12K
0x0F_D000
2K
0x13_F800
128K
7E_0000
9S12XD128
8K
0x0F_E000
2K
0x13_F800
128K
7E_0000
9S12XD64
4K
0x0F_F000
1K
0x13_FC00
64K
7F_0000
9S12XB128
6K
0x0F_E800
1K
0x13_FC00
128K
7E_0000
9S12XA128
12K
0x0F_D000
2K
0x13_F800
128K
7E_0000
Device
MC9S12XDP512 Data Sheet, Rev. 2.21
40
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
CPU and BDM
Local Memory Map
Global Memory Map
0x00_0000
0x00_07FF
2K REGISTERS
CS3
Unimplemented
RAM
0x0800
0x0C00
0x1000
RAM
2K REGISTERS
1K EEPROM window
EPAGE
0x0F_FFFF
1K EEPROM
4K RAM window
Unimplemented
EEPROM
RPAGE
CS2
0x0000
RAMSIZE
RAM_LOW
8K RAM
EEPROM_LOW
EEPROM
0x4000
0x13_FFFF
CS2
Unpaged
16K FLASH
EEPROMSIZE
0x2000
0x1F_FFFF
External
Space
CS1
0x8000
PPAGE
0x3F_FFFF
0xC000
CS0
16K FLASH window
Unimplemented
FLASH
Unpaged
16K FLASH
0xFFFF
Reset Vectors
0x78_0000
Unimplemented
FLASH
FLASH1_HIGH
CS0
FLASH0_LOW
FLASHSIZE
FLASH0
FLASH1
0x7F_FFFF
Figure 1-4. S12X CPU & BDM Global Address Mapping
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
41
Chapter 1 Device Overview MC9S12XD-Family
Table 1-3. Device Internal Resources (see Figure 1-4)
RAMSIZE/
RAM_LOW
EEPROMSIZE/
EEPROM_LOW
FLASHSIZE0/
FLASH_LOW
FLASHSIZE1/
FLASH_HIGH
9S12XDT384
20K
0x0F_B000
4K
0x13_F000
128K
0x79_FFFF
256K
0x7C_0000
9S12XDQ256
16K
0x0F_C000
4K
0x13_F000
9S12XDT256
16K
0x0F_C000
4K
0x13_F000
9S12XD256
14K
0x0F_C800
4K
0x13_F000
128K
0x79_FFFF
128K
0x7E_0000
9S12XA256
16K
0x0F_C000
4K
0x13_F000
9S12XB256
10K
0x0F_D800
2K
0x13_F800
Device
MC9S12XDP512 Data Sheet, Rev. 2.21
42
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
XGATE
Local Memory Map
Figure 1-5. GATE Global Address Mapping
Global Memory Map
0x00_0000
Registers
0x00_07FF
XGRAM_LOW
0x0800
RAM
0x0F_FFFF
RAMSIZE
Registers
XGRAMSIZE
0x0000
FLASH
RAM
0x78_0800
0xFFFF
FLASHSIZE
FLASH
XGFLASH_HIGH
0x7F_FFFF
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
43
Chapter 1 Device Overview MC9S12XD-Family
Table 1-4. XGATE Resources (see Figure 1-5)
Device
1
XGRANMSIZE
XGRAM_LOW
9S12XDP512
32K
0x0F_8000
9S12XDT512
20K
0x0F_B000
9S12XDT384
20K
0x0F_B000
9S12XA512
32K
0x0F_8000
9S12XDQ256
16K
0x0F_C000
9S12XD256
14K
0x0F_C800
9S12XB256
10K
0x0F_D800
9S12XA256
16K
0x0F_C000
XGFLASHSIZE1
XGFLASH_HIGH
30K
0x78_7FFF
Available Flah Memory 30K on all listed parts
MC9S12XDP512 Data Sheet, Rev. 2.21
44
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
XGATE
Local Memory Map
Figure 1-6. XGATE Global Address Mapping
Global Memory Map
0x00_0000
Registers
0x00_07FF
XGRAM_LOW
0x0800
RAM
0x0F_FFFF
RAMSIZE
Registers
XGRAMSIZE
0x0000
RAM
0xFFFF
0x7F_FFFF
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
45
Chapter 1 Device Overview MC9S12XD-Family
Table 1-5. XGATE Resources (see Figure 1-6)
Device
XGRAMSIZE
XGRAM_LOW
9S12XDG128
12K
0x0F_D000
3S12XDG128
12K
0x0F_D000
9S12XD128
8K
0x0F_E000
9S12XD64
4K
0x0F_F000
9S12XB128
6K
0x0F_E800
9S12XA128
12K
0x0F_D000
MC9S12XDP512 Data Sheet, Rev. 2.21
46
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
1.1.5
Part ID Assignments & Maskset Numbers
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 1-6 shows the assigned part ID
number and Mask Set number.
Table 1-6. Part Names, Masksets and Assigned Part ID Numbers
Part Names
Mask Set Number
Part ID1
MC9S12XDP512
0L15Y/1L15Y/0M23S
0xC410/0xC411/0xC412
MC9S12XDT512
0L15Y/1L15Y/0M23S
0xC410/0xC411/0xC412
MC9S12XA512
0L15Y/1L15Y/0M23S
0xC410/0xC411/0xC412
MC9S12XDT384
MC9S12XDQ256
MC9S12XDT256
0M84E/1M84E
0xC000/0xC001
0L15Y/1L15Y/0M23S
0xC410/0xC4110xC412
0M84E/1M84E
0xC000/0xC001
0xC410/0xC411/0xC412
0M84E/1M84E
0xC000/0xC001
MC9S12XB256
0L15Y/1L15Y/0M23S
0xC410/0xC411/0xC412
0M84E/1M84E
0xC000/0xC001
MC9S12XA256
0L15Y/1L15Y/0M23S
0xC410/0xC411/0xC412
0M84E/1M84E
0xC000/0xC001
0L15Y/1L15Y/0M23S
0xC410/0xC411/0xC412
0M42E/1M42E/2M42E
0xC100/0xC101/0xC102
0L15Y/1L15Y/0M23S
0xC410/0xC4110xC412
0M42E/1M42E/2M42E
0xC100/0xC101/0xC102
0L15Y/1L15Y/0M23S
0xC410/0xC411/0xC412
0M42E/1M42E/2M42E
0xC100/0xC101/0xC102
0L15Y/1L15Y/0M23S
0xC410/0xC411/0xC412
0M42E/1M42E/2M42E
0xC100/0xC101/0xC102
MC9S12XDG128
MC9S12XD128
MC9S12XA128
MC9S12XB128
1.2
0xC410/0xC411/0xC412
0xC410/0xC411/0xC412
0L15Y/1L15Y/0M23S
MC9S12XD256
1
0L15Y/1L15Y/0M23S
0L15Y/1L15Y/0M23S
The coding is as follows:
Bit 15-12: Major family identifier
Bit 11-8: Minor family identifier
Bit 7-4: Major mask set revision number including FAB transfers
Bit 3-0: Minor — non full — mask set revision
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.
1.2.1
Device Pinout
The MC9S12XD family of devices offers pin-compatible packaged devices to assist with system
development and accommodate expansion of the application.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
47
Chapter 1 Device Overview MC9S12XD-Family
The S12XD, S12XA and S12XB family devices are offered in the following packages:
• 144-pin LQFP package with an external bus interface (address/data bus)
• 112-pin LQFP without external bus interface
• 80-pin QFP without external bus interface
See Appendix E Derivative Differences for package options.
CAUTION
Most the I/O Pins have different functionality depending on the module
configuration. Not all functions are shown in the following pinouts. Please
refer to Table 1-7 for a complete description. For avalability of the modules
on different family members refer to Appendix E Derivative Differences.
For pinout explanations of the different parts refer to E.7 Pinout
explanations:
MC9S12XDP512 Data Sheet, Rev. 2.21
48
Freescale Semiconductor
144
143
142
141
140
139
138
137
136
135
134
133
132
131
130
129
128
127
126
125
124
123
122
121
120
119
118
117
116
115
114
113
112
111
110
109
PP4/KWP4/PWM4/MISO2
PP5/KPW5/PWM5/MOSI2
PP6/KWP6/PWM6/SS2
PP7/KWP7/PWM7/SCK2
PK7/ROMCTL/EWAIT
VDDX1
VSSX1
PM0/RXCAN0
PM1/TXCAN0
PM2/RXCAN1/RXCAN0/MISO0
PM3/TXCAN1/TXCAN0/SS0
PM4/RXCAN2/RXCAN0/RXCAN4/MOSI0
PM5/TXCAN2/TXCAN0/TXCAN4/SCK0
PJ4/KWJ4/SDA1/CS0
PJ5/KWJ5/SCL1/CS2
PJ6/KWJ6/RXCAN4/SDA0/RXCAN0
PJ7/KWJ7/TXCAN4/SCL0/TXCAN0
VREGEN
PS7/SS0
PS6/SCK0
PS5/MOSI0
PS4/MISO0
PS3/TXD1
PS2/RXD1
PS1/TXD0
PS0/RXD0
PM6/RXCAN3/RXCAN4/RXD3
PM7/TXCAN3/TXCAN4/TXD3
PAD23/AN23
PAD22/AN22
PAD21/AN21
PAD20/AN20
PAD19/AN19
PAD18/AN18
VSSA
VRL
Chapter 1 Device Overview MC9S12XD-Family
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
29
30
31
32
33
34
35
36
MC9S12XD-Family
144-Pin LQFP
Pins shown in BOLD-ITALICS are not available on the
112-Pin LQFP or the 80-Pin QFP package option
Pins shown in BOLD are not available on the
80-Pin QFP package option
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
VRH
VDDA
PAD17/AN17
PAD16/AN16
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
VDD2
PD7/DATA7
PD6/DATA6
PD5/DATA5
PD4/DATA4
VDDR2
VSSR2
PA7/ADDR15
PA6/ADDR14
PA5/ADDR13
PA4/ADDR12
PA3/ADDR11
PA2/ADDR10
PA1/ADDR9
PA0/ADDR8
ADDR5/PB5
ADDR6/PB6
ADDR7/PB7
DATA12/PC4
DATA13/PC5
DATA14/PC6
DATA15/PC7
TXD5/SS2/KWH7/PH7
RXD5/SCK2/KWH6/PH6
TXD4/MOSI2/KWH5/PH5
RXD4/MISO2/KWH4/PH4
XCLKS/ECLKX2/PE7
TAGHI/MODB/PE6
RE/TAGLO/MODA/PE5
ECLK/PE4
VSSR1
VDDR1
RESET
VDDPLL
XFC
VSSPLL
EXTAL
XTAL
TEST
SS1/KWH3/PH3
SCK1/KWH2/PH2
MOSI1/KWH1/PH1
MISO1/KWH0/PH0
PD0/DATA0
PD1/DATA1
PD2/DATA2
PD3/DATA3
LDS/LSTRB/PE3/EROMCTL
WE/R/W/PE2
IRQ/PE1
XIRQ/PE0
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
SS1/PWM3/KWP3/PP3
SCK1/PWM2/KWP2/PP2
MOSI1/PWM1/KWP1/PP1
MISO1/PWM0/KWP0/PP0
CS1/KWJ2/PJ2
ACC2/ADDR22/PK6
IQSTAT3/ADDR19/PK3
IQSTAT2/ADDR18/PK2
IQSTAT1/ADDR17/PK1
IQSTAT0/ADDR16/PK0
IOC0/PT0
IOC1/PT1
IOC2/PT2
IOC3/PT3
VDD1
VSS1
IOC4/PT4
IOC5/PT5
IOC6/PT6
IOC7/PT7
ACC1/ADDR21/PK5
ACC0/ADDR20/PK4
TXD2/KWJ1/PJ1
CS3/RXD2/KWJ0/PJ0
MODC/BKGD
VDDX2
VSSX2
DATA8/PC0
DATA9/PC1
DATA10/PC2
DATA11/PC3
UDS/ADDR0/PB0
ADDR1/PB1
ADDR2/PB2
ADDR3/PB3
ADDR4/PB4
Figure 1-7. MC9S12XD Family Pin Assignment 144-Pin LQFP Package
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
49
MC9S12XD-Family
112-Pin LQFP
Pins shown in BOLD are not available on the
80-Pin QFP package option
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
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
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
VDD2
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PB5
PB6
PB7
TXD5/SS2/KWH7/PH7
RXD5/SCK2/KWH6/PH6
TXD4/MOSI2/KWH5/PH5
RXD4/MISO2/KWH4/PH4
XCLKS/PE7
PE6
PE5
ECLK/PE4
VSSR1
VDDR1
RESET
VDDPLL
XFC
VSSPLL
EXTAL
XTAL
TEST
SS1/KWH3/PH3
SCK1/KWH2/PH2
MOSI1/KWH1/PH1
MISO1/KWH0/PH0
PE3
PE2
IRQ/PE1
XIRQ/PE0
SS1/PWM3/KWP3/PP3
SCK1/PWM2/KWP2/PP2
MOSI1/PWM1/KWP1/PP1
MISO1/PWM0/KWP0/PP0
PK3
PK2
PK1
PK0
IOC0/PT0
IOC1/PT1
IOC2/PT2
IOC3/PT3
VDD1
VSS1
IOC4/PT4
IOC5/PT5
IOC6/PT6
IOC7/PT7
PK5
PK4
TXD2/KWJ1/PJ1
RXD2/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/MISO2
PP5/KPW5/PWM5/MOSI2
PP6/KWP6/PWM6/SS2
PP7/KWP7/PWM7/SCK2
PK7
VDDX
VSSX
PM0/RXCAN0
PM1/TXCAN0
PM2/RXCAN1/RXCAN0/MISO0
PM3/TXCAN1/TXCAN0/SS0
PM4/RXCAN2/RXCAN0/RXCAN4/MOS
PM5/TXCAN2/TXCAN0/TXCAN4/SCK0
PJ6/KWJ6/RXCAN4/SDA0/RXCAN0
PJ7/KWJ7/TXCAN4/SCL0/TXCAN0
VREGEN
PS7/SS0
PS6/SCK0
PS5/MOSI0
PS4/MISO0
PS3/TXD1
PS2/RXD1
PS1/TXD0
PS0/RXD0
PM6/RXCAN3/RXCAN4/RXD3
PM7/TXCAN3/TXCAN4/TXD3
VSSA
VRL
Chapter 1 Device Overview MC9S12XD-Family
Figure 1-8. MC9S12XD Family Pin Assignments 112-Pin LQFP Package
MC9S12XDP512 Data Sheet, Rev. 2.21
50
Freescale Semiconductor
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
MC9S12XD-Family
80-Pin QFP
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
VRH
VDDA
PAD07/AN07
PAD06/AN06
PAD05/AN05
PAD04/AN04
PAD03/AN03
PAD02/AN02
PAD01/AN01
PAD00/AN00
VSS2
VDD2
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
PB5
PB6
PB7
XCLKS/PE7
PE6
PE5
ECLK/PE4
VSSR1
VDDR1
RESET
VDDPLL
XFC
VSSPLL
EXTAL
XTAL
TEST
PE3
PE2
IRQ/PE1
XIRQ/PE0
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
SS1/PWM3/KWP3/PP3
SCK1/PWM2/KWP2/PP2
MOSI1/PWM1/KWP1/PP1
MISO1/PWM0/KWP0/PP0
IOC0/PT0
IOC1/PT1
IOC2/PT2
IOC3/PT3
VDD1
VSS1
IOC4/PT4
IOC5/PT5
IOC6/PT6
IOC7/PT7
MODC/BKGD
PB0
PB1
PB2
PB3
PB4
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
PP4/KWP4/PWM4/MISO2
PP5/KWP5/PWM5/MOSI2
PP7/KWP7/PWM7/SCK2
VDDX
VSSX
PM0/RXCAN0
PM1/TXCAN0
PM2/RXCAN1/RXCAN0/MISO0
PM3/TXCAN1/TXCAN0/SS0
PM4/RXCAN2/RXCAN0/RXCAN4/MOSI0
PM5/TXCAN2/TXCAN0/TXCAN4/SCK0
PJ6/KWJ6/RXCAN4/SDA0/RXCAN0
PJ7/KWJ7/TXCAN4/SCL0/TXCAN0
VREGEN
PS3/TXD1
PS2/RXD1
PS1/TXD0
PS0/RXD0
VSSA
VRL
Chapter 1 Device Overview MC9S12XD-Family
Figure 1-9. MC9S12XD Family Pin Assignments 80-Pin QFP Package
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
51
Chapter 1 Device Overview MC9S12XD-Family
1.2.2
Signal Properties Summary
Table 1-7 summarizes the pin functionality of the MC9S12XDP512. For available modules on other parts
of the S12XD, S12XB and S12XA family please refer to Appendix E Derivative Differences.
Table 1-7. Signal Properties Summary (Sheet 1 of 4)
Pin
Pin
Pin
Pin
Pin
Power
Name
Name
Name
Name
Name
Supply
Function 1 Function 2 Function 3 Function 4 Function 5
Internal Pull
Resistor
Description
CTRL
Reset
State
EXTAL
—
—
—
—
VDDPLL
NA
NA
XTAL
—
—
—
—
VDDPLL
NA
NA
RESET
—
—
—
—
VDDR
TEST
—
—
—
—
N.A.
RESET pin
VREGEN
—
—
—
—
VDDX
PUCR
Up
Voltage regulator enable
Input
PULLUP
Oscillator pins
External reset
DOWN Test input
XFC
—
—
—
—
VDDPLL
NA
NA
PLL loop filter
BKGD
MODC
—
—
—
VDDX
Always on
Up
Background debug
PAD[23:08]
AN[23:8]
—
—
—
VDDA
PER0/
PER1
Disabled Port AD I/O, Port AD inputs
of ATD1 and
analog inputs of ATD1
PAD[07:00]
AN[7:0]
—
—
—
VDDA
PER1
Disabled Port AD I/O, Port AD inputs
of ATD0 and
analog inputs of ATD0
PA[7:0]
—
—
—
—
VDDR
PUCR
Disabled Port A I/O
PB[7:0]
—
—
—
—
VDDR
PUCR
Disabled Port BI/O
PA[7:0]
ADDR[15:8] IVD[15:8]
—
—
VDDR
PUCR
Disabled Port A I/O, address bus,
internal visibility data
PB[7:1]
ADDR[7:1]
IVD[7:0]
—
—
VDDR
PUCR
Disabled Port B I/O, address bus,
internal visibility data
PB0
ADDR0
UDS
VDDR
PUCR
Disabled Port B I/O, address bus,
upper data strobe
PC[7:0]
DATA[15:8]
—
—
—
VDDR
PUCR
Disabled Port C I/O, data bus
PD[7:0]
DATA[7:0]
—
—
—
VDDR
PUCR
Disabled Port D I/O, data bus
PE7
ECLKX2
XCLKS
—
—
VDDR
PUCR
PE6
TAGHI
MODB
—
—
VDDR
While RESET
pin is low: down
Port E I/O, tag high, mode
input
PE5
RE
MODA
TAGLO
—
VDDR
While RESET
pin is low: down
Port E I/O, read enable,
mode input, tag low input
Up
Port E I/O, system clock
output, clock select
PE4
ECLK
—
—
—
VDDR
PUCR
Up
Port E I/O, bus clock output
PE3
LSTRB
LDS
EROMCTL
—
VDDR
PUCR
Up
Port E I/O, low byte data
strobe, EROMON control
PE2
R/W
WE
—
—
VDDR
PUCR
Up
Port E I/O, read/write
PE1
IRQ
—
—
—
VDDR
PUCR
Up
Port E Input, maskable
interrupt
MC9S12XDP512 Data Sheet, Rev. 2.21
52
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
Table 1-7. Signal Properties Summary (Sheet 2 of 4)
Pin
Pin
Pin
Pin
Pin
Power
Name
Name
Name
Name
Name
Supply
Function 1 Function 2 Function 3 Function 4 Function 5
Internal Pull
Resistor
Description
CTRL
Reset
State
PUCR
Up
PE0
XIRQ
—
—
—
VDDR
Port E input, non-maskable
interrupt
PH7
KWH7
SS2
TXD5
—
VDDR
PH6
KWH6
SCK2
RXD5
—
VDDR
PERH/
PPSH
Disabled Port H I/O, interrupt, SCK of
SPI2, RXD of SCI5
PH5
KWH5
MOSI2
TXD4
—
VDDR
PERH/
PPSH
Disabled Port H I/O, interrupt, MOSI
of SPI2, TXD of SCI4
PH4
KWH4
MISO2
RXD4
—
VDDR
PERH/PPSH Disabled Port H I/O, interrupt, MISO
of SPI2, RXD of SCI4
PH3
KWH3
SS1
—
—
VDDR
PERH/PPSH Disabled Port H I/O, interrupt, SS of
SPI1
PH2
KWH2
SCK1
—
—
VDDR
PERH/PPSH Disabled Port H I/O, interrupt, SCK of
SPI1
PH1
KWH1
MOSI1
—
—
VDDR
PERH/PPSH Disabled Port H I/O, interrupt, MOSI
of SPI1
PH0
KWH0
MISO1
—
—
VDDR
PERH/PPSH Disabled Port H I/O, interrupt, MISO
of SPI1
PJ7
KWJ7
TXCAN4
SCL0
TXCAN0
VDDX
PERJ/
PPSJ
Up
Port J I/O, interrupt, TX of
CAN4, SCL of IIC0, TX of
CAN0
PJ6
KWJ6
RXCAN4
SDA0
RXCAN0
VDDX
PERJ/
PPSJ
Up
Port J I/O, interrupt, RX of
CAN4, SDA of IIC0, RX of
CAN0
PJ5
KWJ5
SCL1
CS2
—
VDDX
PERJ/
PPSJ
Up
Port J I/O, interrupt, SCL of
IIC1, chip select 2
PJ4
KWJ4
SDA1
CS0
—
VDDX
PERJ/
PPSJ
Up
Port J I/O, interrupt, SDA of
IIC1, chip select 0
PJ2
KWJ2
CS1
—
—
VDDX
PERJ/
PPSJ
Up
Port J I/O, interrupt, chip
select 1
PJ1
KWJ1
TXD2
—
—
VDDX
PERJ/
PPSJ
Up
Port J I/O, interrupt, TXD of
SCI2
PJ0
KWJ0
RXD2
CS3
—
VDDX
PERJ/
PPSJ
Up
Port J I/O, interrupt, RXD of
SCI2
PK7
—
—
—
—
VDDX
PUCR
Up
Port K I/O
PK[5:4]
—
—
—
—
VDDX
PUCR
Up
Port K I/O
PK7
EWAIT
ROMCTL
—
—
VDDX
PUCR
Up
Port K I/O, EWAIT input,
ROM on control
PK[6:4]
ADDR
[22:20]
ACC[2:0]
—
—
VDDX
PUCR
Up
Port K I/O, extended
addresses, access source
for external access
PK3
ADDR19
IQSTAT3
—
—
VDDX
PUCR
Up
Extended address, PIPE
status
PERH/PPSH Disabled Port H I/O, interrupt, SS of
SPI2, TXD of SCI5
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
53
Chapter 1 Device Overview MC9S12XD-Family
Table 1-7. Signal Properties Summary (Sheet 3 of 4)
Pin
Pin
Pin
Pin
Pin
Power
Name
Name
Name
Name
Name
Supply
Function 1 Function 2 Function 3 Function 4 Function 5
Internal Pull
Resistor
Description
CTRL
Reset
State
PK2
ADDR18
IQSTAT2
—
—
VDDX
PUCR
Up
Extended address, PIPE
status
PK1
ADDR17
IQSTAT1
—
—
VDDX
PUCR
Up
Extended address, PIPE
status
PK0
ADDR16
IQSTAT0
—
—
VDDX
PUCR
Up
Extended address, PIPE
status
PM7
TXCAN3
TXD3
TXCAN4
—
VDDX
PERM/
PPSM
PM6
RXCAN3
RXD3
RXCAN4
—
VDDX PERM/PPSM Disabled Port M I/O RX of CAN3 and
CAN4, RXD of SCI3
PM5
TXCAN2
TXCAN0
TXCAN4
SCK0
VDDX PERM/PPSM Disabled Port M I/O CAN0, CAN2,
CAN4, SCK of SPI0
PM4
RXCAN2
RXCAN0
RXCAN4
MOSI0
VDDX PERM/PPSM Disabled Port M I/O, CAN0, CAN2,
CAN4, MOSI of SPI0
PM3
TXCAN1
TXCAN0
—
SS0
VDDX PERM/PPSM Disabled Port M I/O TX of CAN1,
CAN0, SS of SPI0
PM2
RXCAN1
RXCAN0
—
MISO0
VDDX PERM/PPSM Disabled Port M I/O, RX of CAN1,
CAN0, MISO of SPI0
PM1
TXCAN0
—
—
VDDX PERM/PPSM Disabled Port M I/O, TX of CAN0
PM0
RXCAN0
—
—
VDDX PERM/PPSM Disabled Port M I/O, RX of CAN0
PP7
KWP7
PWM7
SCK2
—
VDDX
PERP/
PPSP
Disabled Port P I/O, interrupt, channel
7
of PWM, SCK of SPI2
PP6
KWP6
PWM6
SS2
—
VDDX
PERP/
PPSP
Disabled Port P I/O, interrupt, channel
6 of PWM, SS of SPI2
PP5
KWP5
PWM5
MOSI2
—
VDDX
PERP/
PPSP
Disabled Port P I/O, interrupt, channel
5 of PWM, MOSI of SPI2
PP4
KWP4
PWM4
MISO2
—
VDDX
PERP/
PPSP
Disabled Port P I/O, interrupt, channel
4 of PWM, MISO2 of SPI2
PP3
KWP3
PWM3
SS1
—
VDDX
PERP/
PPSP
Disabled Port P I/O, interrupt, channel
3 of PWM, SS of SPI1
PP2
KWP2
PWM2
SCK1
—
VDDX
PERP/
PPSP
Disabled Port P I/O, interrupt, channel
2 of PWM, SCK of SPI1
PP1
KWP1
PWM1
MOSI1
—
VDDX
PERP/
PPSP
Disabled Port P I/O, interrupt, channel
1 of PWM, MOSI of SPI1
PP0
KWP0
PWM0
MISO1
—
VDDX
PERP/
PPSP
Disabled Port P I/O, interrupt, channel
0 of PWM, MISO2 of SPI1
PS7
SS0
—
—
—
VDDX
PERS/
PPSS
Up
Port S I/O, SS of SPI0
PS6
SCK0
—
—
—
VDDX
PERS/
PPSS
Up
Port S I/O, SCK of SPI0
Disabled Port M I/O, TX of CAN3 and
CAN4, TXD of SCI3
MC9S12XDP512 Data Sheet, Rev. 2.21
54
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
Table 1-7. Signal Properties Summary (Sheet 4 of 4)
Pin
Pin
Pin
Pin
Pin
Power
Name
Name
Name
Name
Name
Supply
Function 1 Function 2 Function 3 Function 4 Function 5
Internal Pull
Resistor
Description
CTRL
Reset
State
PS5
MOSI0
—
—
—
VDDX
PERS/
PPSS
Up
Port S I/O, MOSI of SPI0
PS4
MISO0
—
—
—
VDDX
PERS/
PPSS
Up
Port S I/O, MISO of SPI0
PS3
TXD1
—
—
—
VDDX
PERS/
PPSS
Up
Port S I/O, TXD of SCI1
PS2
RXD1
—
—
—
VDDX
PERS/
PPSS
Up
Port S I/O, RXD of SCI1
PS1
TXD0
—
—
—
VDDX
PERS/
PPSS
Up
Port S I/O, TXD of SCI0
PS0
RXD0
—
—
—
VDDX
PERS/
PPSS
Up
Port S I/O, RXD of SCI0
PT[7:0]
IOC[7:0]
—
—
—
VDDX
PERT/
PPST
Disabled Port T I/O, timer channels
NOTE
For devices assembled in 80-pin and 112-pin 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 1-7 for affected pins.
1.2.3
Detailed Signal Descriptions
NOTE
This section describes all pins which are availabe on the cover part
MC9S12XDP512 in 144-pin LQFP package. For modules and pinout
explanations of the different family members refer to E.7 Pinout
explanations: and E.5 Peripheral Sets S12XD - Family and E.6 Peripheral
Sets S12XA & S12XB - Family
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 crystal 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 ;ow to indicate when any internal MCU reset source triggers.
The RESET pin has an internal pullup device.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
55
Chapter 1 Device Overview MC9S12XD-Family
1.2.3.3
TEST — Test Pin
This input only pin is reserved for test. This pin has a pulldown device.
NOTE
The TEST pin must be tied to VSS in all applications.
1.2.3.4
VREGEN — Voltage Regulator Enable Pin
This input only pin enables or disables the on-chip voltage regulator. The input has a pullup device.
1.2.3.5
XFC — PLL Loop Filter Pin
Please ask your Freescale representative for the interactive application note to compute PLL loop filter
elements. Any current leakage on this pin must be avoided.
VDDPLL
VDDPLL
CS
MCU
R0
CP
XFC
Figure 1-10. PLL Loop Filter Connections
1.2.3.6
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 a pullup device.
1.2.3.7
PAD[23:8] / AN[23:8] — Port AD Input Pins of ATD1
PAD[23:8] are general-purpose input or output pins and analog inputs AN[23:8] of the analog-to-digital
converter ATD1.
1.2.3.8
PAD[7:0] / AN[7:0] — Port AD Input Pins of ATD0
PAD[7:0] are general-purpose input or output pins and analog inputs AN[7:0] of the analog-to-digital
converter ATD0.
1.2.3.9
PAD[15:0] / AN[15:0] — Port AD Input Pins of ATD1
PAD[15:0] are general-purpose input or output pins and analog inputs AN[15:0] of the analog-to-digital
converter ATD1.
MC9S12XDP512 Data Sheet, Rev. 2.21
56
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
1.2.3.10
PA[7:0] / ADDR[15:8] / IVD[15:8] — Port A I/O Pins
PA[7:0] are general-purpose input or output pins. In MCU expanded modes of operation, these pins are
used for the external address bus. In MCU emulation modes of operation, these pins are used for external
address bus and internal visibility read data.
1.2.3.11
PB[7:1] / ADDR[7:1] / IVD[7:1] — Port B I/O Pins
PB[7:1] are general-purpose input or output pins. In MCU expanded modes of operation, these pins are
used for the external address bus. In MCU emulation modes of operation, these pins are used for external
address bus and internal visibility read data.
1.2.3.12
PB0 / ADDR0 / UDS / IVD[0] — Port B I/O Pin 0
PB0 is a general-purpose input or output pin. In MCU expanded modes of operation, this pin is used for
the external address bus ADDR0 or as upper data strobe signal. In MCU emulation modes of operation,
this pin is used for external address bus ADDR0 and internal visibility read data IVD0.
1.2.3.13
PB[7:0] — Port B I/O Pins
PB[7:0] are general-purpose input or output pins.
1.2.3.14
PC[7:0] / DATA [15:8] — Port C I/O Pins
PC[7:0] are general-purpose input or output pins. In MCU expanded modes of operation, these pins are
used for the external data bus.
The input voltage thresholds for PC[7:0] can be configured to reduced levels, to allow data from an external
3.3-V peripheral to be read by the MCU operating at 5.0 V. The input voltage thresholds for PC[7:0] are
configured to reduced levels out of reset in expanded and emulation modes. The input voltage thresholds
for PC[7:0] are configured to 5-V levels out of reset in normal modes.
1.2.3.15
PD[7:0] / DATA [7:0] — Port D I/O Pins
PD[7:0] are general-purpose input or output pins. In MCU expanded modes of operation, these pins are
used for the external data bus.
The input voltage thresholds for PD[7:0] can be configured to reduced levels, to allow data from an
external 3.3-V peripheral to be read by the MCU operating at 5.0 V. The input voltage thresholds for
PD[7:0] are configured to reduced levels out of reset in expanded and emulation modes. The input voltage
thresholds for PC[7:0] are configured to 5-V levels out of reset in normal modes.
1.2.3.16
PE7 / ECLKX2 / XCLKS — Port E I/O Pin 7
PE7 is a general-purpose input or output pin. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
57
Chapter 1 Device Overview MC9S12XD-Family
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
The selected oscillator configuration is frozen with the rising edge of reset.
The pin can be configured to drive the internal system clock ECLKX2.
EXTAL
C1
MCU
Crystal or
Ceramic Resonator
XTAL
C2
VSSPLL
Figure 1-11. Loop Controlled Pierce Oscillator Connections (PE7 = 1)
EXTAL
C1
MCU
RB
RS
Crystal or
Ceramic Resonator
XTAL
C2
VSSPLL
Figure 1-12. Full Swing Pierce Oscillator Connections (PE7 = 0)
EXTAL
CMOS-Compatible
External Oscillator
MCU
XTAL
Not Connected
Figure 1-13. External Clock Connections (PE7 = 0)
1.2.3.17
PE6 / MODB / TAGHI — Port E I/O Pin 6
PE6 is a general-purpose input or output pin. It is used as a MCU operating mode select pin during reset.
The state of this pin is latched to the MODB bit at the rising edge of RESET. This pin is an input with a
MC9S12XDP512 Data Sheet, Rev. 2.21
58
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
pull-down device which is only active when RESET is low. TAGHI is used to tag the high half of the
instruction word being read into the instruction queue.
The input voltage threshold for PE6 can be configured to reduced levels, to allow data from an external
3.3-V peripheral to be read by the MCU operating at 5.0 V. The input voltage threshold for PE6 is
configured to reduced levels out of reset in expanded and emulation modes.
1.2.3.18
PE5 / MODA / TAGLO / RE — Port E I/O Pin 5
PE5 is a general-purpose input or output pin. It is used as a MCU operating mode select pin during reset.
The state of this pin is latched to the MODA bit at the rising edge of RESET. This pin is shared with the
read enable RE output. This pin is an input with a pull-down device which is only active when RESET is
low. TAGLO is used to tag the low half of the instruction word being read into the instruction queue.
The input voltage threshold for PE5 can be configured to reduced levels, to allow data from an external
3.3-V peripheral to be read by the MCU operating at 5.0 V. The input voltage threshold for PE5 is
configured to reduced levels out of reset in expanded and emulation modes.
1.2.3.19
PE4 / ECLK — Port E I/O Pin 4
PE4 is a general-purpose input or output pin. It can be configured to drive the internal bus clock ECLK.
ECLK can be used as a timing reference.
1.2.3.20
PE3 / LSTRB / LDS / EROMCTL— Port E I/O Pin 3
PE3 is a general-purpose input or output pin. In MCU expanded modes of operation, LSTRB or LDS can
be used for the low byte strobe function to indicate the type of bus access. At the rising edge of RESET
the state of this pin is latched to the EROMON bit.
1.2.3.21
PE2 / R/W / WE— Port E I/O Pin 2
PE2 is a general-purpose input or output pin. In MCU expanded modes of operations, this pin drives the
read/write output signal or write enable output signal for the external bus. It indicates the direction of data
on the external bus
1.2.3.22
PE[6:2] — Port E I/O Pins
PE[6:2] are general-purpose input or output pins.
1.2.3.23
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.
1.2.3.24
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
59
Chapter 1 Device Overview MC9S12XD-Family
1.2.3.25
PH7 / KWH7 / SS2 / TXD5 — Port H I/O Pin 7
PH7 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured as slave select pin SS of the serial peripheral
interface 2 (SPI2). It can be configured as the transmit pin TXD of serial communication interface 5
(SCI5).
1.2.3.26
PH6 / KWH6 / SCK2 / RXD5 — Port H I/O Pin 6
PH6 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured as serial clock pin SCK of the serial peripheral
interface 2 (SPI2). It can be configured as the receive pin (RXD) of serial communication interface 5
(SCI5).
1.2.3.27
PH5 / KWH5 / MOSI2 / TXD4 — Port H I/O Pin 5
PH5 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured as master output (during master mode) or slave input
pin (during slave mode) MOSI of the serial peripheral interface 2 (SPI2). It can be configured as the
transmit pin TXD of serial communication interface 4 (SCI4).
1.2.3.28
PH4 / KWH4 / MISO2 / RXD4 — Port H I/O Pin 4
PH4 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured as master input (during master mode) or slave output
(during slave mode) pin MISO of the serial peripheral interface 2 (SPI2). It can be configured as the receive
pin RXD of serial communication interface 4 (SCI4).
1.2.3.29
PH3 / KWH3 / SS1 — Port H I/O Pin 3
PH3 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured as slave select pin SS of the serial peripheral
interface 1 (SPI1).
1.2.3.30
PH2 / KWH2 / SCK1 — Port H I/O Pin 2
PH2 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured as serial clock pin SCK of the serial peripheral
interface 1 (SPI1).
1.2.3.31
PH1 / KWH1 / MOSI1 — Port H I/O Pin 1
PH1 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured as master output (during master mode) or slave input
pin (during slave mode) MOSI of the serial peripheral interface 1 (SPI1).
MC9S12XDP512 Data Sheet, Rev. 2.21
60
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
1.2.3.32
PH0 / KWH0 / MISO1 — Port H I/O Pin 0
PH0 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured as master input (during master mode) or slave output
(during slave mode) pin MISO of the serial peripheral interface 1 (SPI1).
1.2.3.33
PJ7 / KWJ7 / TXCAN4 / SCL0 / TXCAN0— PORT J I/O Pin 7
PJ7 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as the transmit pin TXCAN for the scalable controller area
network controller 0 or 4 (CAN0 or CAN4) or as the serial clock pin SCL of the IIC0 module.
1.2.3.34
PJ6 / KWJ6 / RXCAN4 / SDA0 / RXCAN0 — PORT J I/O Pin 6
PJ6 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as the receive pin RXCAN for the scalable controller area
network controller 0 or 4 (CAN0 or CAN4) or as the serial data pin SDA of the IIC0 module.
1.2.3.35
PJ5 / KWJ5 / SCL1 / CS2 — PORT J I/O Pin 5
PJ5 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as the serial clock pin SCL of the IIC1 module. It can be
configured to provide a chip-select output.
1.2.3.36
PJ4 / KWJ4 / SDA1 / CS0 — PORT J I/O Pin 4
PJ4 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as the serial data pin SDA of the IIC1 module. It can be
configured to provide a chip-select output.
1.2.3.37
PJ2 / KWJ2 / CS1 — PORT J I/O Pin 2
PJ2 is a general-purpose input or output pins. It can be configured to generate an interrupt causing the
MCU to exit stop or wait mode. It can be configured to provide a chip-select output.
1.2.3.38
PJ1 / KWJ1 / TXD2 — PORT J I/O Pin 1
PJ1 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as the transmit pin TXD of the serial communication
interface 2 (SCI2).
1.2.3.39
PJ0 / KWJ0 / RXD2 / CS3 — PORT J I/O Pin 0
PJ0 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as the receive pin RXD of the serial communication interface
2 (SCI2).It can be configured to provide a chip-select output.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
61
Chapter 1 Device Overview MC9S12XD-Family
1.2.3.40
PK7 / EWAIT / ROMCTL — Port K I/O Pin 7
PK7 is a general-purpose input or output pin. During MCU emulation modes and normal expanded modes
of operation, this pin is used to enable the Flash EEPROM memory in the memory map (ROMCTL). At
the rising edge of RESET, the state of this pin is latched to the ROMON bit. The EWAIT input signal
maintains the external bus access until the external device is ready to capture data (write) or provide data
(read).
The input voltage threshold for PK7 can be configured to reduced levels, to allow data from an external
3.3-V peripheral to be read by the MCU operating at 5.0 V. The input voltage threshold for PK7 is
configured to reduced levels out of reset in expanded and emulation modes.
1.2.3.41
PK[6:4] / ADDR[22:20] / ACC[2:0] — Port K I/O Pin [6:4]
PK[6:4] are general-purpose input or output pins. During MCU expanded modes of operation, the
ACC[2:0] signals are used to indicate the access source of the bus cycle. This pins also provide the
expanded addresses ADDR[22:20] for the external bus. In Emulation modes ACC[2:0] is available and is
time multiplexed with the high addresses
1.2.3.42
PK[3:0] / ADDR[19:16] / IQSTAT[3:0] — Port K I/O Pins [3:0]
PK3-PK0 are general-purpose input or output pins. In MCU expanded modes of operation, these pins
provide the expanded address ADDR[19:16] for the external bus and carry instruction pipe information.
1.2.3.43
PK7,PK[5:0] — Port K I/O Pins 7 & [5:0]
PK7 and PK[5:0] are general-purpose input or output pins.
1.2.3.44
PM7 / TXCAN3 / TXCAN4 / TXD3 — Port M I/O Pin 7
PM7 is a general-purpose input or output pin. It can be configured as the transmit pin TXCAN of the
scalable controller area network controller 3 or 4 (CAN3 or CAN4). PM7 can be configured as the transmit
pin TXD3 of the serial communication interface 3 (SCI3).
1.2.3.45
PM6 / RXCAN3 / RXCAN4 / RXD3 — Port M I/O Pin 6
PM6 is a general-purpose input or output pin. It can be configured as the receive pin RXCAN of the
scalable controller area network controller 3 or 4 (CAN3 or CAN4). PM6 can be configured as the receive
pin RXD3 of the serial communication interface 3 (SCI3).
1.2.3.46
PM5 / TXCAN0 / TXCAN2 / TXCAN4 / SCK0 — Port M I/O Pin 5
PM5 is a general-purpose input or output pin. It can be configured as the transmit pin TXCAN of the
scalable controller area network controllers 0, 2 or 4 (CAN0, CAN2, or CAN4). It can be configured as
the serial clock pin SCK of the serial peripheral interface 0 (SPI0).
MC9S12XDP512 Data Sheet, Rev. 2.21
62
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
1.2.3.47
PM4 / RXCAN0 / RXCAN2 / RXCAN4 / MOSI0 — Port M I/O Pin 4
PM4 is a general-purpose input or output pin. It can be configured as the receive pin RXCAN of the
scalable controller area network controllers 0, 2, or 4 (CAN0, CAN2, or CAN4). 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).
1.2.3.48
PM3 / TXCAN1 / TXCAN0 / SS0 — Port M I/O Pin 3
PM3 is a general-purpose input or output pin. It can be configured as the transmit pin TXCAN of the
scalable controller area network controllers 1 or 0 (CAN1 or CAN0). It can be configured as the slave
select pin SS of the serial peripheral interface 0 (SPI0).
1.2.3.49
PM2 / RXCAN1 / RXCAN0 / MISO0 — Port M I/O Pin 2
PM2 is a general-purpose input or output pin. It can be configured as the receive pin RXCAN of the
scalable controller area network controllers 1 or 0 (CAN1 or CAN0). 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).
1.2.3.50
PM1 / TXCAN0 — 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).
1.2.3.51
PM0 / RXCAN0 — 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).
1.2.3.52
PP7 / KWP7 / PWM7 / SCK2 — Port P I/O Pin 7
PP7 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as pulse width modulator (PWM) channel 7 output. It can
be configured as serial clock pin SCK of the serial peripheral interface 2 (SPI2).
1.2.3.53
PP6 / KWP6 / PWM6 / SS2 — Port P I/O Pin 6
PP6 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as pulse width modulator (PWM) channel 6 output. It can
be configured as slave select pin SS of the serial peripheral interface 2 (SPI2).
1.2.3.54
PP5 / KWP5 / PWM5 / MOSI2 — Port P I/O Pin 5
PP5 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as pulse width modulator (PWM) channel 5 output. It can
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
63
Chapter 1 Device Overview MC9S12XD-Family
be configured as master output (during master mode) or slave input pin (during slave mode) MOSI of the
serial peripheral interface 2 (SPI2).
1.2.3.55
PP4 / KWP4 / PWM4 / MISO2 — Port P I/O Pin 4
PP4 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as pulse width modulator (PWM) channel 4 output. It can
be configured as master input (during master mode) or slave output (during slave mode) pin MISO of the
serial peripheral interface 2 (SPI2).
1.2.3.56
PP3 / KWP3 / PWM3 / SS1 — Port P I/O Pin 3
PP3 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as pulse width modulator (PWM) channel 3 output. It can
be configured as slave select pin SS of the serial peripheral interface 1 (SPI1).
1.2.3.57
PP2 / KWP2 / PWM2 / SCK1 — Port P I/O Pin 2
PP2 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as pulse width modulator (PWM) channel 2 output. It can
be configured as serial clock pin SCK of the serial peripheral interface 1 (SPI1).
1.2.3.58
PP1 / KWP1 / PWM1 / MOSI1 — Port P I/O Pin 1
PP1 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as pulse width modulator (PWM) channel 1 output. It can
be configured as master output (during master mode) or slave input pin (during slave mode) MOSI of the
serial peripheral interface 1 (SPI1).
1.2.3.59
PP0 / KWP0 / PWM0 / MISO1 — Port P I/O Pin 0
PP0 is a general-purpose input or output pin. It can be configured to generate an interrupt causing the MCU
to exit stop or wait mode. It can be configured as pulse width modulator (PWM) channel 0 output. It can
be configured as master input (during master mode) or slave output (during slave mode) pin MISO of the
serial peripheral interface 1 (SPI1).
1.2.3.60
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).
1.2.3.61
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).
MC9S12XDP512 Data Sheet, Rev. 2.21
64
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
1.2.3.62
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).
1.2.3.63
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).
1.2.3.64
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).
1.2.3.65
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).
1.2.3.66
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).
1.2.3.67
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).
1.2.3.68
PT[7:0] / IOC[7:0] — Port T I/O Pins [7:0]
PT[7:0] are general-purpose input or output pins. They can be configured as input capture or output
compare pins IOC[7:0] of the enhanced capture timer (ECT).
1.2.4
Power Supply Pins
MC9S12XDP512RMV2 power and ground pins are described below.
NOTE
All VSS pins must be connected together in the application.
1.2.4.1
VDDX1, VDDX2, VSSX1,VSSX2 — Power and Ground Pins for I/O Drivers
External power and ground for I/O drivers. 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. Bypass requirements depend on how heavily the MCU pins are
loaded.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
65
Chapter 1 Device Overview MC9S12XD-Family
1.2.4.2
VDDR1, VDDR2, VSSR1, VSSR2 — Power and Ground Pins for I/O Drivers
and for Internal Voltage Regulator
External power and ground for I/O drivers and input to the internal voltage regulator. 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. Bypass requirements
depend on how heavily the MCU pins are loaded.
1.2.4.3
VDD1, VDD2, VSS1, VSS2 — Core Power Pins
Power is supplied to the MCU through VDD and VSS. 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. This 2.5-V supply is derived from the
internal voltage regulator. There is no static load on those pins allowed. The internal voltage regulator is
turned off, if VREGEN is tied to ground.
NOTE
No load allowed except for bypass capacitors.
1.2.4.4
VDDA, VSSA — Power Supply Pins for ATD and VREG
VDDA, VSSA are the power supply and ground input pins for the voltage regulator and the analog-to-digital
converters.
1.2.4.5
VRH, VRL — ATD Reference Voltage Input Pins
VRH and VRL are the reference voltage input pins for the analog-to-digital converter.
1.2.4.6
VDDPLL, VSSPLL — Power Supply Pins for PLL
Provides operating voltage and ground for the oscillator and the phased-locked loop. This allows the
supply voltage to the oscillator and PLL to be bypassed independently. This 2.5-V voltage is generated by
the internal voltage regulator.
NOTE
No load allowed except for bypass capacitors.
MC9S12XDP512 Data Sheet, Rev. 2.21
66
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
Table 1-8. MC9S12XD Family Power and Ground Connection Summary
Pin Number
Mnemonic
Nominal
Voltage
144-Pin
LQFP
112-Pin
LQFP
80-Pin
QFP
VDD1, 2
15, 87
13, 65
9, 49
2.5 V
VSS1, 2
16, 88
14, 66
10, 50
0V
VDDR1
53
41
29
5.0 V
VSSR1
52
40
28
0V
VDDX1
139
107
77
5.0 V
VSSX1
138
106
76
0V
VDDX2
26
N.A.
N.A.
5.0 V
VSSX2
27
N.A.
N.A.
0V
VDDR2
82
N.A.
N.A.
5.0 V
VSSR2
81
N.A.
N.A.
0V
VDDA
107
83
59
5.0 V
VSSA
110
86
62
0V
VRL
109
85
61
0V
VRH
108
84
60
5.0 V
VDDPLL
55
43
31
2.5 V
VSSPLL
57
45
33
0V
Description
Internal power and ground generated by
internal regulator
External power and ground, supply to pin
drivers and internal voltage regulator
External power and ground, supply to pin
drivers
External power and ground, supply to pin
drivers
External power and ground, supply to pin
drivers
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.
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
67
Chapter 1 Device Overview MC9S12XD-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 1-12 shows the clock connections from the CRG to all modules.
See 79Chapterf or details on clock generation.
SCI Modules
SPI Modules
CAN Modules
IIC Modules
ATD Modules
Bus Clock
PIT
EXTAL
Oscillator Clock
ECT
CRG
PIM
XTAL
Core Clock
RAM
S12X
XGATE
FLASH
EEPROM
Figure 1-14. MC9S12XD Family Clock Connections
The MCU’s 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
The clock generated by the PLL or oscillator provides the main system clock frequencies core clock and
bus clock. As shown in Figure 1-12, this system clocks are used throughout the MCU to drive the core, the
memories, and the peripherals.
The program Flash memory and the EEPROM are 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 NVM’s. See the Flash
and EEPROM section for more details on the operation of the NVM’s.
MC9S12XDP512 Data Sheet, Rev. 2.21
68
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
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. Consult MSCAN block description for more details on the operation and configuration of
the CAN blocks.
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
Chip Configuration Summary
CAUTION
Emulation single chip mode, Normal expanded mode, Emulation expanded
mode and ROMCTL/EROMCTL functionality is only available on parts
with external bus interface in 144 LQFP package. see Appendix E
Derivative Differences.
The MCU can operate in six different modes. The different modes, the state of ROMCTL and EROMCTL
signal on rising edge of RESET, and the security state of the MCU affects the following device
characteristics:
• External bus interface configuration
• Flash in memory map, or not
• Debug features enabled or disabled
The operating mode out of reset is determined by the states of the MODC, MODB, and MODA signals
during reset (see Table 1-9). The MODC, MODB, and MODA bits in the MODE register show the current
operating mode and provide limited mode switching during operation. The states of the MODC, MODB,
and MODA signals are latched into these bits on the rising edge of RESET.
In normal expanded mode and in emulation modes the ROMON bit and the EROMON bit in the
MMCCTL1 register defines if the on chip flash memory is the memory map, or not. (See Table 1-9.) For
a detailed description of the ROMON and EROMON bits refer to the S12X_MMC section.
The state of the ROMCTL signal is latched into the ROMON bit in the MMCCTL1 register on the rising
edge of RESET. The state of the EROMCTL signal is latched into the EROMON bit in the MISC register
on the rising edge of RESET.
The MCU can operate in two different modes. The operating mode out of reset is determined by the state
of the MODC signal during reset. The MODC bit in the MODE register shows the current operating mode
and provide limited mode switching during operation. The state of the MODC signal is latched into this
bit on the rising edge of RESET.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
69
Chapter 1 Device Overview MC9S12XD-Family
Table 1-9. Chip Modes and Data Sources
BKGD =
MODC
PE6 =
MODB
PE5 =
MODA
PK7 =
ROMCTL
PE3 =
EROMCTL
1
0
0
X
X
Internal
Special single chip
0
0
0
Emulation single chip
0
0
1
X
0
Emulation memory
X
1
Internal Flash
0
X
External application
1
X
Internal Flash
0
X
External application
1
0
Emulation memory
1
1
Internal Flash
Chip Modes
Normal single chip
Normal expanded
1
0
1
Emulation expanded
0
1
1
Special test
1
0
1
0
Data Source1
0
X
External application
1
X
Internal Flash
Internal means resources inside the MCU are read/written.
Internal Flash means Flash resources inside the MCU are read/written.
Emulation memory means resources inside the emulator are read/written (PRU registers, Flash replacement, RAM, EEPROM,
and register space are always considered internal).
External application means resources residing outside the MCU are read/written.
The configuration of the oscillator can be selected using the XCLKS signal (see Table 1-10). For a detailed
description please refer to the S12CRG section.
Table 1-10. Clock Selection Based on PE7
PE7 = XCLKS
Description
0
Full swing Pierce oscillator or external clock source selected
1
Loop controlled Pierce oscillator selected
The logic level on the voltage regulator enable pin VREGEN determines whether the on-chip voltage
regulator is enabled or disabled (see Table 1-11).
Table 1-11. Voltage Regulator VREGEN
VREGEN
Description
1
Internal voltage regulator enabled
0
Internal voltage regulator disabled, VDD1,2 and VDDPLL must be
supplied externally
MC9S12XDP512 Data Sheet, Rev. 2.21
70
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
1.5
1.5.1
1.5.1.1
Modes of Operation
User Modes
Normal Expanded Mode
Ports K, A, and B are configured as a 23-bit address bus, ports C and D are configured as a 16-bit data bus,
and port E provides bus control and status signals. This mode allows 16-bit external memory and
peripheral devices to be interfaced to the system. The fastest external bus rate is divide by 2 from the
internal bus rate.
1.5.1.2
Normal Single-Chip Mode
There is no external bus in this mode. The processor program is executed from internal memory. Ports A,
B,C,D, K, and most pins of port E are available as general-purpose I/O.
1.5.1.3
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 is waiting for additional serial commands through the BKGD pin. There
is no external bus after reset in this mode.
1.5.1.4
Emulation of Expanded Mode
Developers use this mode for emulation systems in which the users target application is normal expanded
mode. Code is executed from external memory or from internal memory depending on the state of
ROMON and EROMON bit. In this mode the internal operation is visible on external bus interface.
1.5.1.5
Emulation of Single-Chip Mode
Developers use this mode for emulation systems in which the user’s target application is normal
single-chip mode. Code is executed from external memory or from internal memory depending on the state
of ROMON and EROMON bit. In this mode the internal operation is visible on external bus interface.
1.5.1.6
Special Test Mode
Freescale internal use only.
1.5.2
Low-Power Modes
The microcontroller features two main low-power modes. Consult the respective sections for information
on the module 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 S12CRG section.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
71
Chapter 1 Device Overview MC9S12XD-Family
1.5.2.1
System Stop Modes
The system stop modes are entered if the CPU executes the STOP instruction and the XGATE doesn’t
execute a thread and the XGFACT bit in the XGMCTL register is cleared. 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 ends the system stop modes.
1.5.2.2
Pseudo Stop Mode
In this mode the clocks are stopped but the oscillator is still running and the real time interrupt (RTI) or
watchdog (COP) submodule can stay active. Other peripherals are turned off. This mode consumes more
current than the system stop mode, but the wake up time from this mode is significantly shorter.
1.5.2.3
Full Stop Mode
The oscillator is stopped in this mode. All clocks are switched off. All counters and dividers remain frozen.
1.5.2.4
System 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 and the XGATE 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 has not been masked ends system wait
mode.
1.5.3
Freeze Mode
The enhanced capture timer, pulse width modulator, analog-to-digital converters, the periodic interrupt
timer and the XGATE module provide a software programmable option to freeze the module status during
the background debug module is active. This is useful when debugging application software. For detailed
description of the behavior of the ATD0, ATD1, ECT, PWM, XGATE and PIT when the background debug
module is active consult the corresponding sections..
1.6
Resets and Interrupts
Consult the S12XCPU Block Guide for information on exception processing.
1.6.1
Vectors
Table 1-12 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
I-bit maskable service request is a configuration register. It selects if the service request is enabled, the
service request priority level and whether the service request is handled either by the S12X CPU or by the
XGATE module.
MC9S12XDP512 Data Sheet, Rev. 2.21
72
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
Table 1-12. Interrupt Vector Locations (Sheet 1 of 3)
Vector Address1
XGATE
Channel ID2
Interrupt Source
CCR
Mask
Local Enable
$FFFE
—
System reset or illegal access reset
None
None
$FFFC
—
Clock monitor reset
None
PLLCTL (CME, SCME)
$FFFA
—
COP watchdog reset
None
COP rate select
Vector base + $F8
—
Unimplemented instruction trap
None
None
Vector base+ $F6
—
SWI
None
None
Vector base+ $F4
—
XIRQ
X Bit
None
Vector base+ $F2
—
IRQ
I bit
IRQCR (IRQEN)
Vector base+ $F0
$78
Real time interrupt
I bit
CRGINT (RTIE)
Vector base+ $EE
$77
Enhanced capture timer channel 0
I bit
TIE (C0I)
Vector base + $EC
$76
Enhanced capture timer channel 1
I bit
TIE (C1I)
Vector base+ $EA
$75
Enhanced capture timer channel 2
I bit
TIE (C2I)
Vector base+ $E8
$74
Enhanced capture timer channel 3
I bit
TIE (C3I)
Vector base+ $E6
$73
Enhanced capture timer channel 4
I bit
TIE (C4I)
Vector base+ $E4
$72
Enhanced capture timer channel 5
I bit
TIE (C5I)
Vector base + $E2
$71
Enhanced capture timer channel 6
I bit
TIE (C6I)
Vector base+ $E0
$70
Enhanced capture timer channel 7
I bit
TIE (C7I)
Vector base+ $DE
$6F
Enhanced capture timer overflow
I bit
TSRC2 (TOF)
Vector base+ $DC
$6E
Pulse accumulator A overflow
I bit
PACTL (PAOVI)
Vector base + $DA
$6D
Pulse accumulator input edge
I bit
PACTL (PAI)
Vector base + $D8
$6C
SPI0
I bit
SPI0CR1 (SPIE, SPTIE)
Vector base+ $D6
$6B
SCI0
I bit
SCI0CR2
(TIE, TCIE, RIE, ILIE)
Vector base + $D4
$6A
SCI1
I bit
SCI1CR2
(TIE, TCIE, RIE, ILIE)
Vector base + $D2
$69
ATD0
I bit
ATD0CTL2 (ASCIE)
Vector base + $D2
Reserved
Vector base + $D0
$68
ATD1
I bit
ATD1CTL2 (ASCIE)
Vector base + $CE
$67
Port J
I bit
PIEJ (PIEJ7-PIEJ0)
Vector base + $CC
$66
Port H
I bit
PIEH (PIEH7-PIEH0)
Vector base + $CA
$65
Modulus down counter underflow
I bit
MCCTL(MCZI)
Vector base + $C8
$64
Pulse accumulator B overflow
I bit
PBCTL(PBOVI)
Vector base + $C6
$63
CRG PLL lock
I bit
CRGINT(LOCKIE)
Vector base + $C4
$62
CRG self-clock mode
I bit
CRGINT (SCMIE)
I bit
IBCR0 (IBIE)
Vector base + $C2
Vector base + $C0
Reserved
$60
IIC0 bus
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
73
Chapter 1 Device Overview MC9S12XD-Family
Table 1-12. Interrupt Vector Locations (Sheet 2 of 3)
Vector Address1
XGATE
Channel ID2
Interrupt Source
CCR
Mask
Local Enable
Vector base + $BE
$5F
SPI1
I bit
SPI1CR1 (SPIE, SPTIE)
Vector base + $BC
$5E
SPI2
I bit
SPI2CR1 (SPIE, SPTIE)
Vector base + $BC
RESERVED
Vector base + $BA
$5D
EEPROM
I bit
ECNFG (CCIE, CBEIE)
Vector base + $B8
$5C
FLASH
I bit
FCNFG (CCIE, CBEIE)
Vector base + $B6
$5B
CAN0 wake-up
I bit
CAN0RIER (WUPIE)
Vector base + $B4
$5A
CAN0 errors
I bit
CAN0RIER (CSCIE, OVRIE)
Vector base + $B2
$59
CAN0 receive
I bit
CAN0RIER (RXFIE)
Vector base + $B0
$58
CAN0 transmit
I bit
CAN0TIER (TXEIE[2:0])
Vector base + $AE
$57
CAN1 wake-up
I bit
CAN1RIER (WUPIE)
Vector base + $AC
$56
CAN1 errors
I bit
CAN1RIER (CSCIE, OVRIE)
Vector base + $AA
$55
CAN1 receive
I bit
CAN1RIER (RXFIE)
Vector base + $A8
$54
CAN1 transmit
I bit
CAN1TIER (TXEIE[2:0])
Vector base + $A6
$53
CAN2 wake-up
I bit
CAN2RIER (WUPIE)
Vector base + $A4
$52
CAN2 errors
I bit
CAN2RIER (CSCIE, OVRIE)
Vector base + $A2
$51
CAN2 receive
I bit
CAN2RIER (RXFIE)
Vector base + $A0
$50
CAN2 transmit
I bit
CAN2TIER (TXEIE[2:0])
Vector base + $9E
$4F
CAN3 wake-up
I bit
CAN3RIER (WUPIE)
Vector base+ $9C
$4E
CAN3 errors
I bit
CAN3RIER (CSCIE, OVRIE)
Vector base+ $9A
$4D
CAN3 receive
I bit
CAN3RIER (RXFIE)
Vector base + $98
$4C
CAN3 transmit
I bit
CAN3TIER (TXEIE[2:0])
Vector base + $AE
to
Vector base + 98
Reserved
Vector base + $9E
to
Vector base + 98
Reserved
Vector base + $96
$4B
CAN4 wake-up
I bit
CAN4RIER (WUPIE)
Vector base + $94
$4A
CAN4 errors
I bit
CAN4RIER (CSCIE, OVRIE)
Vector base + $92
$49
CAN4 receive
I bit
CAN4RIER (RXFIE)
Vector base + $90
$48
CAN4 transmit
I bit
CAN4TIER (TXEIE[2:0])
Vector base + $8E
$47
Port P Interrupt
I bit
PIEP (PIEP7-PIEP0)
Vector base+ $8C
$46
PWM emergency shutdown
I bit
PWMSDN (PWMIE)
Vector base + $8A
$45
SCI2
I bit
SCI2CR2
(TIE, TCIE, RIE, ILIE)
MC9S12XDP512 Data Sheet, Rev. 2.21
74
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
Table 1-12. Interrupt Vector Locations (Sheet 3 of 3)
Vector Address1
XGATE
Channel ID2
Interrupt Source
CCR
Mask
Vector base + $88
$44
SCI3
I bit
SCI3CR2
(TIE, TCIE, RIE, ILIE)
Vector base + $8A
to
Vector base + $88
Reserved
Vector base + $86
$43
SCI4
I bit
SCI4CR2
(TIE, TCIE, RIE, ILIE)
Vector base + $84
$42
SCI5
I bit
SCI5CR2
(TIE, TCIE, RIE, ILIE)
I bit
IBCR (IBIE)
Vector base + $86
to
Vector base + $84
Vector base + $82
Reserved
$41
Vector base + $82
Vector base + $80
$40
Low-voltage interrupt (LVI)
I bit
VREGCTRL (LVIE)
Vector base + $7E
$3F
Autonomous periodical interrupt (API)
I bit
VREGAPICTRL (APIE)
Reserved
Vector base + $7A
$3D
Periodic interrupt timer channel 0
I bit
PITINTE (PINTE0)
Vector base + $78
$3C
Periodic interrupt timer channel 1
I bit
PITINTE (PINTE1)
Vector base + $76
$3B
Periodic interrupt timer channel 2
I bit
PITINTE (PINTE2)
Vector base + $74
$3A
Periodic interrupt timer channel 3
I bit
PITINTE (PINTE3)
Vector base + $72
$39
XGATE software trigger 0
I bit
XGMCTL (XGIE)
Vector base + $70
$38
XGATE software trigger 1
I bit
XGMCTL (XGIE)
Vector base + $6E
$37
XGATE software trigger 2
I bit
XGMCTL (XGIE)
Vector base + $6C
$36
XGATE software trigger 3
I bit
XGMCTL (XGIE)
Vector base + $6A
$35
XGATE software trigger 4
I bit
XGMCTL (XGIE)
Vector base + $68
$34
XGATE software trigger 5
I bit
XGMCTL (XGIE)
Vector base + $66
$33
XGATE software trigger 6
I bit
XGMCTL (XGIE)
Vector base + $64
$32
XGATE software trigger 7
I bit
XGMCTL (XGIE)
Vector base + $62
—
XGATE software error interrupt
I bit
XGMCTL (XGIE)
Vector base + $60
—
S12XCPU RAM access violation
I bit
RAMWPC (AVIE)
—
None
Vector base+ $12
to
Vector base + $5E
Vector base + $10
2
IIC1 Bus
Reserved
Vector base + $7C
1
Local Enable
Reserved
—
Spurious interrupt
16 bits vector address based
For detailed description of XGATE channel ID refer to XGATE Block Guide
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
75
Chapter 1 Device Overview MC9S12XD-Family
1.6.2
Effects of Reset
When a reset occurs, MCU registers and control bits are changed to known start-up states. Refer to the
respective module Block Guides for register reset states.
1.6.2.1
I/O Pins
Refer to the PIM Block Guide for reset configurations of all peripheral module ports.
1.6.2.2
Memory
The RAM array is not initialized out of reset.
1.7
COP Configuration
The COP timeout rate bits CR[2:0] and the WCOP bit in the COPCTL register are loaded on rising edge
of RESET from the Flash control register FCTL ($0107) located in the Flash EEPROM block. See
Table 1-13 and Table 1-14 for coding. The FCTL register is loaded from the Flash configuration field byte
at global address $7FFF0E during the reset sequence
NOTE
If the MCU is secured the COP timeout rate is always set to the longest
period (CR[2:0] = 111) after COP reset.
Table 1-13. Initial COP Rate Configuration
NV[2:0] in
FCTL Register
CR[2:0] in
COPCTL Register
000
111
001
110
010
101
011
100
100
011
101
010
110
001
111
000
Table 1-14. Initial WCOP Configuration
NV[3] in
FCTL Register
WCOP in
COPCTL Register
1
0
0
1
MC9S12XDP512 Data Sheet, Rev. 2.21
76
Freescale Semiconductor
Chapter 1 Device Overview MC9S12XD-Family
1.8
ATD0 External Trigger Input Connection
The ATD_10B8C module includes four external trigger inputs ETRIG0, ETRIG1, ETRIG, and ETRIG3.
The external trigger allows the user to synchronize ATD conversion to external trigger events. Table 1-15
shows the connection of the external trigger inputs on MC9S12XDP512RMV2.
Table 1-15. ATD0 External Trigger Sources
External Trigger
Input
Connected to . .
ETRIG0
Pulse width modulator channel 1
ETRIG1
Pulse width modulator channel 3
ETRIG2
Periodic interrupt timer hardware trigger0
PITTRIG[0].
ETRIG3
Periodic interrupt timer hardware trigger1
PITTRIG[1].
See Section Chapter 5, “Analog-to-Digital Converter (S12ATD10B8CV2) for information about the
analog-to-digital converter module. When this section refers to freeze mode this is equivalent to active
BDM mode.
1.9
ATD1 External Trigger Input Connection
The ATD_10B16C module includes four external trigger inputs ETRIG0, ETRIG1, ETRIG, and ETRIG3.
The external trigger feature allows the user to synchronize ATD conversion to external trigger events.
Table 1-16 shows the connection of the external trigger inputs on MC9S12XDP512RMV2.
Table 1-16. ATD1 External Trigger Sources
External Trigger
Input
Connected to . .
ETRIG0
Pulse width modulator channel 1
ETRIG1
Pulse width modulator channel 3
ETRIG2
Periodic interrupt timer hardware trigger0
PITTRIG[0].
ETRIG3
Periodic interrupt timer hardware trigger1
PITTRIG[1].
See Section Chapter 4, “Analog-to-Digital Converter (ATD10B16CV4) Block Description for information
about the analog-to-digital converter module. When this section refers to freeze mode this is equivalent to
active BDM mode.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
77
Chapter 1 Device Overview MC9S12XD-Family
MC9S12XDP512 Data Sheet, Rev. 2.21
78
Freescale Semiconductor
Chapter 2
Clocks and Reset Generator (S12CRGV6)
2.1
Introduction
This specification describes the function of the clocks and reset generator (CRG).
2.1.1
Features
The main features of this block are:
• Phase locked loop (PLL) frequency multiplier
— Reference divider
— Automatic bandwidth control mode for low-jitter operation
— 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
— Low voltage reset
— Illegal address reset
— COP reset
— Loss of clock reset
— External pin reset
• Real-time interrupt (RTI)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
79
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.1.2
Modes of Operation
This subsection lists and briefly describes all operating modes supported by the CRG.
• Run mode
All functional parts of the CRG 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 nonzero value.
• Wait mode
In this mode, the PLL can be disabled automatically depending on the PLLSEL bit in the CLKSEL
register.
• 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, or 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 CRG 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
80
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.1.3
Block Diagram
Figure 2-1 shows a block diagram of the CRG.
S12X_MMC
Voltage
Regulator
Illegal Address Reset
Power on Reset
Low Voltage Reset
CRG
RESET
CM fail
Clock
Monitor
OSCCLK
EXTAL
Oscillator
XTAL
COP Timeout
XCLKS
Reset
Generator
Clock Quality
Checker
COP
RTI
System Reset
Bus Clock
Core Clock
Oscillator Clock
Registers
XFC
VDDPLL
VSSPLL
PLLCLK
PLL
Clock and Reset
Control
Real Time Interrupt
PLL Lock Interrupt
Self Clock Mode
Interrupt
Figure 2-1. CRG Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
81
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.2
External Signal Description
This section lists and describes the signals that connect off chip.
2.2.1
VDDPLL and VSSPLL — Operating and Ground Voltage Pins
These pins provide operating voltage (VDDPLL) and ground (VSSPLL) for the PLL circuitry. This allows
the supply voltage to the PLL to be independently bypassed. Even if PLL usage is not required, VDDPLL
and VSSPLL must be connected to properly.
2.2.2
XFC — External Loop Filter Pin
A passive external loop filter must be placed on the XFC pin. The filter is a second-order, low-pass filter
that eliminates the VCO input ripple. The value of the external filter network and the reference frequency
determines the speed of the corrections and the stability of the PLL. Refer to the device specification for
calculation of PLL Loop Filter (XFC) components. If PLL usage is not required, the XFC pin must be tied
to VDDPLL.
VDDPLL
CS
CP
MCU
RS
XFC
Figure 2-2. PLL Loop Filter Connections
2.2.3
RESET — Reset Pin
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 a system reset (internal to the MCU) has
been triggered.
2.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the CRG.
MC9S12XDP512 Data Sheet, Rev. 2.21
82
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.1
Module Memory Map
Table 2-1 gives an overview on all CRG registers.
Table 2-1. CRG Memory Map
Address
Offset
Use
Access
0x_00
CRG Synthesizer Register (SYNR)
R/W
0x_01
CRG Reference Divider Register (REFDV)
R/W
1
0x_02
CRG Test Flags Register (CTFLG)
R/W
0x_03
CRG Flags Register (CRGFLG)
R/W
0x_04
CRG Interrupt Enable Register (CRGINT)
R/W
0x_05
CRG Clock Select Register (CLKSEL)
R/W
0x_06
CRG PLL Control Register (PLLCTL)
R/W
0x_07
CRG RTI Control Register (RTICTL)
R/W
0x_08
CRG COP Control Register (COPCTL)
R/W
0x_09
0x_0A
0x_0B
CRG Force and Bypass Test Register
CRG Test Control Register
(FORBYP)2
(CTCTL)3
CRG COP Arm/Timer Reset (ARMCOP)
R/W
R/W
R/W
1
CTFLG is intended for factory test purposes only.
FORBYP is intended for factory test purposes only.
3 CTCTL is intended for factory test purposes only.
2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
83
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2
Register Descriptions
This section describes in address order all the CRG registers and their individual bits.
Register
Name
SYNR
R
Bit 7
6
5
4
3
2
1
Bit 0
0
0
SYN5
SYN4
SYN3
SYN2
SYN1
SYN0
0
0
REFDV5
REFDV4
REFDV3
REFDV2
REFDV1
REFDV0
0
0
0
0
0
0
0
0
RTIF
PORF
LVRF
LOCKIF
LOCK
TRACK
RTIE
ILAF
0
0
PLLSEL
PSTP
CME
W
REFDV
R
W
CTFLG
R
W
CRGFLG
R
W
CRGINT
R
W
CLKSEL
R
0
PLLON
AUTO
ACQ
FSTWKP
RTDEC
RTR6
RTR5
RTR4
RTR3
WCOP
RSBCK
0
0
0
0
0
0
0
1
0
0
R
0
0
W
Bit 7
Bit 6
R
W
RTICTL
R
W
COPCTL
R
W
FORBYP
LOCKIE
0
W
PLLCTL
0
R
PLLWAI
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
CTCTL
R
W
ARMCOP
= Unimplemented or Reserved
Figure 2-3. S12CRGV6 Register Summary
MC9S12XDP512 Data Sheet, Rev. 2.21
84
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.1
CRG Synthesizer Register (SYNR)
The SYNR register controls the multiplication factor of the PLL. If the PLL is on, the count in the loop
divider (SYNR) register effectively multiplies up the PLL clock (PLLCLK) from the reference frequency
by 2 x (SYNR + 1). PLLCLK will not be below the minimum VCO frequency (fSCM).
( SYNR + 1 )
PLLCLK = 2xOSCCLKx -----------------------------------( REFDV + 1 )
NOTE
If PLL is selected (PLLSEL=1), Bus Clock = PLLCLK / 2
Bus Clock must not exceed the maximum operating system frequency.
R
7
6
0
0
0
0
W
Reset
5
4
3
2
1
0
SYN5
SYN4
SYN3
SYN2
SYN1
SYN0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 2-4. CRG Synthesizer Register (SYNR)
Read: Anytime
Write: Anytime except if PLLSEL = 1
NOTE
Write to this register initializes the lock detector bit and the track detector
bit.
2.3.2.2
CRG Reference Divider Register (REFDV)
The REFDV register provides a finer granularity for the PLL multiplier steps. The count in the reference
divider divides OSCCLK frequency by REFDV + 1.
R
7
6
0
0
W
Reset
0
0
5
4
3
2
1
0
REFDV5
REFDV4
REFDV3
REFDV2
REFDV1
REFDV0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 2-5. CRG Reference Divider Register (REFDV)
Read: Anytime
Write: Anytime except when PLLSEL = 1
NOTE
Write to this register initializes the lock detector bit and the track detector
bit.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
85
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.3
Reserved Register (CTFLG)
This register is reserved for factory testing of the CRG module and is not available in normal modes.
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 2-6. Reserved Register (CTFLG)
Read: Always reads 0x_00 in normal modes
Write: Unimplemented in normal modes
NOTE
Writing to this register when in special mode can alter the CRG
fucntionality.
2.3.2.4
CRG Flags Register (CRGFLG)
This register provides CRG status bits and flags.
7
R
W
Reset
6
5
4
RTIF
PORF
LVRF
LOCKIF
0
1
2
0
3
2
LOCK
TRACK
0
0
1
SCMIF
0
0
SCM
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.
= Unimplemented or Reserved
Figure 2-7. CRG Flags Register (CRGFLG)
Read: Anytime
Write: Refer to each bit for individual write conditions
Table 2-2. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
86
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Table 2-2. CRGFLG Field Descriptions (continued)
Field
Description
5
LVRF
Low Voltage Reset Flag — If low voltage reset feature is not available (see device specification) LVRF always
reads 0. 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
PLL 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 PLL lock condition. This bit is cleared in self clock mode.
Writes have no effect.
0 PLL VCO is not within the desired tolerance of the target frequency.
1 PLL VCO is within the desired tolerance of the target frequency.
2
TRACK
Track Status Bit — TRACK reflects the current state of PLL track condition. This bit is cleared in self clock mode.
Writes have no effect.
0 Acquisition mode status.
1Tracking mode status.
1
SCMIF
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.
0
SCM
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
87
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.5
CRG Interrupt Enable Register (CRGINT)
This register enables CRG interrupt requests.
7
R
W
Reset
6
RTIE
ILAF
0
1
5
0
0
4
LOCKIE
0
3
2
0
0
0
0
1
SCMIE
0
0
0
0
1. 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 2-8. CRG Interrupt Enable Register (CRGINT)
Read: Anytime
Write: Anytime
Table 2-3. CRGINT Field Descriptions
Field
Description
7
RTIE
Real Time Interrupt Enable Bit
0 Interrupt requests from RTI are disabled.
1 Interrupt will be requested whenever RTIF is set.
6
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.
4
LOCKIE
Lock Interrupt Enable Bit
0 LOCK interrupt requests are disabled.
1 Interrupt will be requested whenever LOCKIF is set.
1
SCMIE
Self ClockMmode Interrupt Enable Bit
0 SCM interrupt requests are disabled.
1 Interrupt will be requested whenever SCMIF is set.
MC9S12XDP512 Data Sheet, Rev. 2.21
88
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.6
CRG Clock Select Register (CLKSEL)
This register controls CRG clock selection. Refer to Figure 2-17 for more details on the effect of each bit.
7
R
W
Reset
6
PLLSEL
PSTP
0
0
5
4
0
0
0
0
3
PLLWAI
0
2
0
1
0
RTIWAI
COPWAI
0
0
0
= Unimplemented or Reserved
Figure 2-9. CRG Clock Select Register (CLKSEL)
Read: Anytime
Write: Refer to each bit for individual write conditions
Table 2-4. CLKSEL Field Descriptions
Field
Description
7
PLLSEL
PLL Select Bit — Write anytime. Writing a1 when LOCK = 0 and AUTO = 1, or TRACK = 0 and AUTO = 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.
0 System clocks are derived from OSCCLK (Bus Clock = OSCCLK / 2).
1 System clocks are derived from PLLCLK (Bus Clock = PLLCLK / 2).
6
PSTP
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.
3
PLLWAI
PLL Stops in Wait Mode Bit
Write: Anytime
If PLLWAI is set, the CRG will clear the PLLSEL bit before entering wait mode. The PLLON bit remains set during
wait mode, but the PLL is powered down. Upon exiting wait mode, the PLLSEL bit has to be set manually if PLL
clock is required.
While the PLLWAI bit is set, the AUTO bit is set to 1 in order to allow the PLL to automatically lock on the selected
target frequency after exiting wait mode.
0 PLL keeps running in wait mode.
1 PLL 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
89
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.7
CRG PLL Control Register (PLLCTL)
This register controls the PLL functionality.
R
W
Reset
7
6
5
4
3
2
1
0
CME
PLLON
AUTO
ACQ
FSTWKP
PRE
PCE
SCME
1
1
1
1
0
0
0
1
Figure 2-10. CRG PLL Control Register (PLLCTL)
Read: Anytime
Write: Refer to each bit for individual write conditions
Table 2-5. 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!
Note: 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 PLL circuitry. In self clock mode, the PLL is turned on, but the
PLLON bit reads the last latched value. Write anytime except when PLLSEL = 1.
0 PLL is turned off.
1 PLL is turned on. If AUTO bit is set, the PLL will lock automatically.
5
AUTO
Automatic Bandwidth Control Bit — AUTO selects either the high bandwidth (acquisition) mode or the low
bandwidth (tracking) mode depending on how close to the desired frequency the VCO is running. Write anytime
except when PLLWAI = 1, because PLLWAI sets the AUTO bit to 1.
0 Automatic mode control is disabled and the PLL is under software control, using ACQ bit.
1 Automatic mode control is enabled and ACQ bit has no effect.
4
ACQ
Acquisition Bit
Write anytime. If AUTO=1 this bit has no effect.
0 Low bandwidth filter is selected.
1 High bandwidth filter is selected.
3
FSTWKP
Fast Wake-up from Full Stop Bit — FSTWKP enables fast wake-up from full stop mode. Write anytime. If
self-clock 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 i self-clock mode (see
Section 2.4.1.4, “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
CRG will switch all system clocks to OSCCLK. The SCMIF flag will be set. See application examples in
Figure 2-23 and Figure 2-24.
MC9S12XDP512 Data Sheet, Rev. 2.21
90
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Table 2-5. PLLCTL Field Descriptions (continued)
Field
Description
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
2.3.2.8
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 2.5.2, “Clock Monitor Reset”).
1 Detection of crystal clock failure forces the MCU in self clock mode (see Section 2.4.2.2, “Self Clock Mode”).
CRG RTI Control Register (RTICTL)
This register selects the timeout period for the real time interrupt.
R
W
Reset
7
6
5
4
3
2
1
0
RTDEC
RTR6
RTR5
RTR4
RTR3
RTR2
RTR1
RTR0
0
0
0
0
0
0
0
0
Figure 2-11. CRG RTI Control Register (RTICTL)
Read: Anytime
Write: Anytime
NOTE
A write to this register initializes the RTI counter.
Table 2-6. 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 2-7
1 Decimal based divider value. See Table 2-8
6–4
RTR[6:4]
Real Time Interrupt Prescale Rate Select Bits — These bits select the prescale rate for the RTI. See Table 2-7
and Table 2-8.
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 2-7 and Table 2-8 show all possible divide values selectable by the RTICTL
register. The source clock for the RTI is OSCCLK.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
91
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Table 2-7. RTI Frequency Divide Rates for RTDEC = 0
RTR[6:4] =
RTR[3:0]
000
(OFF)
001
(210)
010
(211)
011
(212)
100
(213)
101
(214)
110
(215)
111
(216)
0000 (÷1)
OFF*
210
211
212
213
214
215
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
92
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Table 2-8. 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
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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
93
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.9
CRG COP Control Register (COPCTL)
This register controls the COP (computer operating properly) watchdog.
7
R
W
WCOP
Reset1
6
RSBCK
0
5
4
3
0
0
0
0
0
WRTMASK
0
2
1
0
CR2
CR1
CR0
1. Refer to Device User Guide (Section: CRG) for reset values of WCOP, CR2, CR1, and CR0.
= Unimplemented or Reserved
Figure 2-12. CRG 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.
The COP time-out period is restarted if one these two conditions is true:
1. Writing a nonzero 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 2-9. 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, 0x_55 can be written as often as desired. Once 0x_AA is written after the 0x_55, the time-out logic
restarts and the user must wait until the next window before writing to ARMCOP. Table 2-10 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
94
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Table 2-9. COPCTL Field Descriptions (continued)
Field
Description
5
WRTMASK
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
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[1:0]
COP Watchdog Timer Rate Select — These bits select the COP time-out rate (see Table 2-10). The COP
time-out period is OSCCLK period divided by CR[2:0] value. 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) reinitializing 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 2-10. COP Watchdog Rates1
1
CR2
CR1
CR0
OSCCLK
Cycles to Time-out
0
0
0
COP disabled
0
0
1
214
0
1
0
216
0
1
1
218
1
0
0
220
1
0
1
222
1
1
0
223
1
1
1
224
OSCCLK cycles are referenced from the previous COP time-out reset
(writing 0x_55/0x_AA to the ARMCOP register)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
95
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.10
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 CRG’s functionality.
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. Reserved Register (FORBYP)
Read: Always read 0x_00 except in special modes
Write: Only in special modes
2.3.2.11
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 CRG’s functionality.
R
7
6
5
4
3
2
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 2-14. Reserved Register (CTCTL)
Read: always read 0x_80 except in special modes
Write: only in special modes
MC9S12XDP512 Data Sheet, Rev. 2.21
96
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.12
CRG COP Timer Arm/Reset Register (ARMCOP)
This register is used to restart the COP time-out period.
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 2-15. ARMCOP Register Diagram
Read: Always reads 0x_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 0x_55 or 0x_AA causes a COP reset. To restart the COP time-out
period you must write 0x_55 followed by a write of 0x_AA. Other instructions may be executed
between these writes but the sequence (0x_55, 0x_AA) must be completed prior to COP end of
time-out period to avoid a COP reset. Sequences of 0x_55 writes or sequences of 0x_AA writes
are allowed. When the WCOP bit is set, 0x_55 and 0x_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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
97
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.4
Functional Description
2.4.1
Functional Blocks
2.4.1.1
Phase Locked Loop (PLL)
The PLL is used to run the MCU from a different time base than the incoming OSCCLK. For increased
flexibility, OSCCLK can be divided in a range of 1 to 16 to generate the reference frequency. This offers
a finer multiplication granularity. The PLL can multiply this reference clock by a multiple of 2, 4, 6,...
126,128 based on the SYNR register.
[ SYNR + 1 ]
PLLCLK = 2 × OSCCLK × -----------------------------------[ REFDV + 1 ]
CAUTION
Although it is possible to set the two dividers to command a very high clock
frequency, do not exceed the specified bus frequency limit for the MCU.
If (PLLSEL = 1), Bus Clock = PLLCLK / 2
The PLL is a frequency generator that operates in either acquisition mode or tracking mode, depending on
the difference between the output frequency and the target frequency. The PLL can change between
acquisition and tracking modes either automatically or manually.
The VCO has a minimum operating frequency, which corresponds to the self clock mode frequency fSCM.
REFERENCE
REFDV <5:0>
EXTAL
REDUCED
CONSUMPTION
OSCILLATOR
OSCCLK
FEEDBACK
REFERENCE
PROGRAMMABLE
DIVIDER
XTAL
CRYSTAL
MONITOR
supplied by:
LOOP
PROGRAMMABLE
DIVIDER
LOCK
LOCK
DETECTOR
VDDPLL/VSSPLL
PDET
PHASE
DETECTOR
UP
DOWN
CPUMP
VCO
VDDPLL
LOOP
FILTER
SYN <5:0>
VDDPLL/VSSPLL
XFC
PIN
PLLCLK
VDD/VSS
Figure 2-16. PLL Functional Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
98
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.4.1.1.1
PLL Operation
The oscillator output clock signal (OSCCLK) is fed through the reference programmable divider and is
divided in a range of 1 to 64 (REFDV + 1) to output the REFERENCE clock. The VCO output clock,
(PLLCLK) is fed back through the programmable loop divider and is divided in a range of 2 to 128 in
increments of [2 x (SYNR + 1)] to output the FEEDBACK clock. Figure 2-16.
The phase detector then compares the FEEDBACK clock, with the REFERENCE clock. Correction pulses
are generated based on the phase difference between the two signals. The loop filter then slightly alters the
DC voltage on the external filter capacitor connected to XFC pin, based on the width and direction of the
correction pulse. The filter can make fast or slow corrections depending on its mode, as described in the
next subsection. The values of the external filter network and the reference frequency determine the speed
of the corrections and the stability of the PLL.
The minimum VCO frequency is reached with the XFC pin forced to VDDPLL. This is the self clock mode
frequency.
2.4.1.1.2
Acquisition and Tracking Modes
The lock detector compares the frequencies of the FEEDBACK clock, and the REFERENCE clock.
Therefore, the speed of the lock detector is directly proportional to the final reference frequency. The
circuit determines the mode of the PLL and the lock condition based on this comparison.
The PLL filter can be manually or automatically configured into one of two possible operating modes:
• Acquisition mode
In acquisition mode, the filter can make large frequency corrections to the VCO. This mode is used
at PLL start-up or when the PLL has suffered a severe noise hit and the VCO frequency is far off
the desired frequency. When in acquisition mode, the TRACK status bit is cleared in the CRGFLG
register.
• Tracking mode
In tracking mode, the filter makes only small corrections to the frequency of the VCO. PLL jitter
is much lower in tracking mode, but the response to noise is also slower. The PLL enters tracking
mode when the VCO frequency is nearly correct and the TRACK bit is set in the CRGFLG register.
The PLL can change the bandwidth or operational mode of the loop filter manually or automatically.
In automatic bandwidth control mode (AUTO = 1), the lock detector automatically switches between
acquisition and tracking modes. Automatic bandwidth control mode also is used to determine when the
PLL clock (PLLCLK) is safe to use as the source for the system and core clocks. If PLL 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 PLL start-up, usually)
or at periodic intervals. In either case, only when the LOCK bit is set, is the PLLCLK clock safe to use as
the source for the system and core clocks. If the PLL is selected as the source for the system and core clocks
and the LOCK bit is clear, the PLL has suffered a severe noise hit and the software must take appropriate
action, depending on the application.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
99
Chapter 2 Clocks and Reset Generator (S12CRGV6)
The following conditions apply when the PLL is in automatic bandwidth control mode (AUTO = 1):
• The TRACK bit is a read-only indicator of the mode of the filter.
• The TRACK bit is set when the VCO frequency is within a certain tolerance, ∆trk, and is clear when
the VCO frequency is out of a certain tolerance, ∆unt.
• The LOCK bit is a read-only indicator of the locked state of the PLL.
• 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.
The PLL can also operate in manual mode (AUTO = 0). Manual mode is used by systems that do not
require an indicator of the lock condition for proper operation. Such systems typically operate well below
the maximum system frequency (fsys) and require fast start-up. The following conditions apply when in
manual mode:
• ACQ is a writable control bit that controls the mode of the filter. Before turning on the PLL in
manual mode, the ACQ bit should be asserted to configure the filter in acquisition mode.
• After turning on the PLL by setting the PLLON bit software must wait a given time (tacq) before
entering tracking mode (ACQ = 0).
• After entering tracking mode software must wait a given time (tal) before selecting the PLLCLK
as the source for system and core clocks (PLLSEL = 1).
2.4.1.2
System Clocks Generator
PLLSEL or SCM
PHASE
LOCK
LOOP
PLLCLK
STOP
1
SYSCLK
÷2
SCM
EXTAL
1
OSCILLATOR
CORE CLOCK
0
WAIT(RTIWAI),
STOP(PSTP,PRE),
RTI ENABLE
BUS CLOCK
RTI
OSCCLK
0
XTAL
CLOCK PHASE
GENERATOR
WAIT(COPWAI),
STOP(PSTP,PCE),
COP ENABLE
COP
CLOCK
MONITOR
GATING
CONDITION
STOP
OSCILLATOR
CLOCK
= CLOCK GATE
Figure 2-17. System Clocks Generator
MC9S12XDP512 Data Sheet, Rev. 2.21
100
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
The clock generator creates the clocks used in the MCU (see Figure 2-17). 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. The
memory blocks use the bus clock. If the MCU enters self clock mode (see Section 2.4.2.2, “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 as shown in Figure 2-18. But note that a CPU cycle corresponds to
one bus clock.
PLL clock mode is selected with PLLSEL bit in the CLKSEL registerr. When selected, the PLL output
clock drives SYSCLK for the main system including the CPU and peripherals. The PLL cannot be turned
off by clearing the PLLON bit, if the PLL 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.
CORE CLOCK
BUS CLOCK / ECLK
Figure 2-18. Core Clock and Bus Clock Relationship
2.4.1.3
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 CRG 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.
2.4.1.4
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 50,000 VCO clock cycles1 is called check window.
1. VCO clock cycles are generated by the PLL when running at minimum frequency fSCM.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
101
Chapter 2 Clocks and Reset Generator (S12CRGV6)
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 2-19 as an example.
check window
1
3
2
50000
49999
VCO
Clock
1
2
3
4
5
4096
OSCCLK
4095
osc ok
Figure 2-19. Check Window Example
The sequence for clock quality check is shown in Figure 2-20.
CM fail
Clock OK
no
exit full stop
POR
SCME = 1 &
FSTWKP = 1
?
LVR
yes
num = 0
FSTWKP = 0
?
Enter SCM
yes
no
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 2-20. Sequence for Clock Quality Check
MC9S12XDP512 Data Sheet, Rev. 2.21
102
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
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.
The clock quality checker enables the PLL and the voltage regulator
(VREG) anytime a clock check has to be performed. An ongoing clock
quality check could also cause a running PLL (fSCM) and an active VREG
during pseudo stop mode or wait mode.
2.4.1.5
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 2.4.1.5, “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 0x_55 and 0x_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 0x_55 or 0x_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.
2.4.1.6
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 1 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.
2.4.2
2.4.2.1
Operating Modes
Normal Mode
The CRG block behaves as described within this specification in all normal modes.
1. A Clock Monitor Reset will always set the SCME bit to logical 1.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
103
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.4.2.2
Self Clock Mode
The VCO has a minimum operating frequency, fSCM. 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 VCO
running at minimum operating frequency; this mode of operation is called self clock mode. This requires
CME = 1 and SCME = 1. If the MCU was clocked by the PLL clock prior to entering self clock mode, the
PLLSEL bit will be cleared. If the external clock signal has stabilized again, the CRG will automatically
select OSCCLK to be the system clock and return to normal mode. Section 2.4.1.4, “Clock Quality
Checker” for more information on entering and leaving self clock mode.
NOTE
In order to detect a potential clock loss the CME bit should be always
enabled (CME = 1)!
If CME bit is disabled and the MCU is configured to run on PLL clock
(PLLCLK), a loss of external clock (OSCCLK) will not be detected and will
cause the system clock to drift towards the VCO’s minimum frequency
fSCM. As soon as the external clock is available again the system clock
ramps up to its PLL target frequency. If the MCU is running on external
clock any loss of clock will cause the system to go static.
2.4.3
Low Power Options
This section summarizes the low power options available in the CRG.
2.4.3.1
Run Mode
The RTI can be stopped by setting the associated rate select bits to 0.
The COP can be stopped by setting the associated rate select bits to 0.
2.4.3.2
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 2-11 lists the individual configuration bits and the parts of the MCU that are affected in wait mode
.
Table 2-11. MCU Configuration During Wait Mode
PLLWAI
RTIWAI
COPWAI
PLL
Stopped
—
—
RTI
—
Stopped
—
COP
—
—
Stopped
After executing the WAI instruction the core requests the CRG to switch MCU into wait mode. The CRG
then checks whether the PLLWAI bit is asserted (Figure 2-21). Depending on the configuration, the CRG
switches the system and core clocks to OSCCLK by clearing the PLLSEL bit and disables the PLL. As
soon as all clocks are switched off wait mode is active.
MC9S12XDP512 Data Sheet, Rev. 2.21
104
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
CPU Req’s
Wait Mode.
PLLWAI=1
?
No
Yes
Clear PLLSEL,
Disable PLL
No
Enter
Wait Mode
CME=1
?
Wait Mode left
due to external reset
No
Yes
Exit Wait w.
ext.RESET
CM Fail
?
INT
?
Yes
No
Yes
Exit Wait w.
CMRESET
No
SCME=1
?
Yes
SCMIE=1
?
Generate
SCM Interrupt
(Wakeup from Wait)
No
Exit
Wait Mode
Yes
Exit
Wait Mode
SCM=1
?
No
Yes
Enter
SCM
Enter
SCM
Continue w.
Normal OP
Figure 2-21. Wait Mode Entry/Exit Sequence
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
105
Chapter 2 Clocks and Reset Generator (S12CRGV6)
There are four different scenarios for the CRG to restart the MCU from wait mode:
• External reset
• Clock monitor reset
• COP reset
• Any interrupt
If the MCU gets an external reset or COP reset during wait mode active, the CRG asynchronously restores
all configuration bits in the register space to its default settings and starts the reset generator. After
completing the reset sequence processing begins by fetching the normal or COP reset vector. Wait mode
is left and the MCU is in run mode again.
If the clock monitor is enabled (CME = 1) the MCU is able to leave wait mode when loss of
oscillator/external clock is detected by a clock monitor fail. If the SCME bit is not asserted the CRG
generates a clock monitor fail reset (CMRESET). The CRG’s behavior for CMRESET is the same
compared to external reset, but another reset vector is fetched after completion of the reset sequence. If the
SCME bit is asserted the CRG generates a SCM interrupt if enabled (SCMIE = 1). After generating the
interrupt the CRG enters self-clock mode and starts the clock quality checker (Section 2.4.1.4, “Clock
Quality Checker”). Then the MCU continues with normal operation.If the SCM interrupt is blocked by
SCMIE = 0, the SCMIF flag will be asserted and clock quality checks will be performed but the MCU will
not wake-up from wait-mode.
If any other interrupt source (e.g., RTI) triggers exit from wait mode, the MCU immediately continues with
normal operation. If the PLL has been powered-down during wait mode, the PLLSEL bit is cleared and
the MCU runs on OSCCLK after leaving wait mode. The software must manually set the PLLSEL bit
again, in order to switch system and core clocks to the PLLCLK.
If wait mode is entered from self-clock mode the CRG will continue to check the clock quality until clock
check is successful. The PLL and voltage regulator (VREG) will remain enabled.
Table 2-12 summarizes the outcome of a clock loss while in wait mode.
2.4.3.3
System 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. All counters and dividers remain frozen but
do not initialize. 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 CRG requests other functional units of the MCU (e.g.,
voltage-regulator) to enter their individual power saving modes (if available). This is the main difference
between pseudo stop mode and wait mode.
If the PLLSEL bit is still set when entering stop mode, the CRG will switch the system and core clocks to
OSCCLK by clearing the PLLSEL bit. Then the CRG disables the PLL, disables the core clock and finally
disables the remaining system clocks. As soon as all clocks are switched off, stop mode is active.
If pseudo stop mode (PSTP = 1) is entered from self-clock mode, the CRG will continue to check the clock
quality until clock check is successful. The PLL and the voltage regulator (VREG) will remain enabled. If
full stop mode (PSTP = 0) is entered from self-clock mode, an ongoing clock quality check will be
stopped. A complete timeout window check will be started when stop mode is left again.
Wake-up from stop mode also depends on the setting of the PSTP bit.
MC9S12XDP512 Data Sheet, Rev. 2.21
106
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Table 2-12. Outcome of Clock Loss in Wait Mode
CME
SCME
SCMIE
0
X
X
Clock failure -->
No action, clock loss not detected.
1
0
X
Clock failure -->
CRG performs Clock Monitor Reset immediately
0
Clock failure -->
Scenario 1: OSCCLK recovers prior to exiting wait mode.
– MCU remains in wait mode,
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start clock quality check,
– Set SCMIF interrupt flag.
Some time later OSCCLK recovers.
– CM no longer indicates a failure,
– 4096 OSCCLK cycles later clock quality check indicates clock o.k.,
– SCM deactivated,
– PLL disabled depending on PLLWAI,
– VREG remains enabled (never gets disabled in wait mode).
– MCU remains in wait mode.
Some time later either a wakeup interrupt occurs (no SCM interrupt)
– Exit wait mode using OSCCLK as system clock (SYSCLK),
– Continue normal operation.
or an External Reset is applied.
– Exit wait mode using OSCCLK as system clock,
– Start reset sequence.
Scenario 2: OSCCLK does not recover prior to exiting wait mode.
– MCU remains in wait mode,
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start clock quality check,
– Set SCMIF interrupt flag,
– Keep performing clock quality checks (could continue infinitely) while in wait mode.
Some time later either a wakeup interrupt occurs (no SCM interrupt)
– Exit wait mode in SCM using PLL clock (fSCM) as system clock,
– Continue to perform additional clock quality checks until OSCCLK is o.k. again.
or an External RESET is applied.
– Exit wait mode in SCM using PLL clock (fSCM) as system clock,
– Start reset sequence,
– Continue to perform additional clock quality checks until OSCCLKis o.k.again.
1
Clock failure -->
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start clock quality check,
– SCMIF set.
SCMIF generates self clock mode wakeup interrupt.
– Exit wait mode in SCM using PLL clock (fSCM) as system clock,
– Continue to perform a additional clock quality checks until OSCCLK is o.k. again.
1
1
1
1
CRG Actions
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
107
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Core req’s
Stop Mode.
Clear PLLSEL,
Disable PLL
Exit Stop w.
ext.RESET
Stop Mode left
due to external reset
No
INT
?
Yes
No
Enter
Stop Mode
PSTP=1
?
Yes
CME=1
?
No
Yes
SCME=1 &
FSTWKP=1
?
No
INT
?
Yes
Yes
CM fail
?
No
No
Yes
No
Exit Stop w.
CMRESET
No
SCME=1
?
Yes
Clock
OK
?
Exit Stop w.
CMRESET
SCME=1
?
Yes
Yes
Exit
Stop Mode
Exit
Stop Mode
no
Exit
Stop Mode
SCMIE=1
?
Generate
SCM Interrupt
(Wakeup from Stop)
No
Exit
Stop Mode
Yes
Exit
Stop Mode
No
SCM=1
?
Yes
Enter
SCM
Enter SCM
SCMIF not
set!
Enter
SCM
Enter
SCM
Continue w.
normal OP
Figure 2-22. Stop Mode Entry/Exit Sequence
MC9S12XDP512 Data Sheet, Rev. 2.21
108
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.4.3.3.1
Wake-up from Pseudo Stop Mode (PSTP=1)
Wake-up from pseudo stop mode is the same as wake-up from wait mode. There are also four different
scenarios for the CRG to restart the MCU from pseudo stop mode:
• External reset
• Clock monitor fail
• COP reset
• Wake-up interrupt
If the MCU gets an external reset or COP reset during pseudo stop mode active, the CRG asynchronously
restores all configuration bits in the register space to its default settings and starts the reset generator. After
completing the reset sequence processing begins by fetching the normal or COP reset vector. pseudo stop
mode is left and the MCU is in run mode again.
If the clock monitor is enabled (CME = 1), the MCU is able to leave pseudo stop mode when loss of
oscillator/external clock is detected by a clock monitor fail. If the SCME bit is not asserted the CRG
generates a clock monitor fail reset (CMRESET). The CRG’s behavior for CMRESET is the same
compared to external reset, but another reset vector is fetched after completion of the reset sequence. If the
SCME bit is asserted the CRG generates a SCM interrupt if enabled (SCMIE = 1). After generating the
interrupt the CRG enters self-clock mode and starts the clock quality checker (Section 2.4.1.4, “Clock
Quality Checker”). Then the MCU continues with normal operation. If the SCM interrupt is blocked by
SCMIE=0, the SCMIF flag will be asserted but the CRG will not wake-up from pseudo stop mode.
If any other interrupt source (e.g., RTI) triggers exit from pseudo stop mode, the MCU immediately
continues with normal operation. Because the PLL 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 set the
PLLSEL bit again, in order to switch system and core clocks to the PLLCLK.
Table 2-13 summarizes the outcome of a clock loss while in pseudo stop mode.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
109
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Table 2-13. Outcome of Clock Loss in Pseudo Stop Mode
CME
SCME
SCMIE
0
X
X
Clock failure -->
No action, clock loss not detected.
1
0
X
Clock failure -->
CRG performs Clock Monitor Reset immediately
0
Clock Monitor failure -->
Scenario 1: OSCCLK recovers prior to exiting pseudo stop mode.
– MCU remains in pseudo stop mode,
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start clock quality check,
– Set SCMIF interrupt flag.
Some time later OSCCLK recovers.
– CM no longer indicates a failure,
– 4096 OSCCLK cycles later clock quality check indicates clock o.k.,
– SCM deactivated,
– PLL disabled,
– VREG disabled.
– MCU remains in pseudo stop mode.
Some time later either a wakeup interrupt occurs (no SCM interrupt)
– Exit pseudo stop mode using OSCCLK as system clock (SYSCLK),
– Continue normal operation.
or an External Reset is applied.
– Exit pseudo stop mode using OSCCLK as system clock,
– Start reset sequence.
Scenario 2: OSCCLK does not recover prior to exiting pseudo stop mode.
– MCU remains in pseudo stop mode,
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start clock quality check,
– Set SCMIF interrupt flag,
– Keep performing clock quality checks (could continue infinitely) while
in pseudo stop mode.
Some time later either a wakeup interrupt occurs (no SCM interrupt)
– Exit pseudo stop mode in SCM using PLL clock (fSCM) as system clock
– Continue to perform additional clock quality checks until OSCCLK is o.k. again.
or an External RESET is applied.
– Exit pseudo stop mode in SCM using PLL clock (fSCM) as system clock
– Start reset sequence,
– Continue to perform additional clock quality checks until OSCCLK is o.k.again.
1
Clock failure -->
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start clock quality check,
– SCMIF set.
SCMIF generates self clock mode wakeup interrupt.
– Exit pseudo stop mode in SCM using PLL clock (fSCM) as system clock,
– Continue to perform a additional clock quality checks until OSCCLK is o.k. again.
1
1
1
1
CRG Actions
MC9S12XDP512 Data Sheet, Rev. 2.21
110
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.4.3.3.2
Wake-up from Full Stop (PSTP = 0)
The MCU requires an external interrupt or an external reset in order to wake-up from stop-mode.
If the MCU gets an external reset during full stop mode active, the CRG asynchronously restores all
configuration bits in the register space to its default settings and will perform a maximum of 50 clock
check_windows (see Section 2.4.1.4, “Clock Quality Checker”). After completing the clock quality check
the CRG starts the reset generator. After completing the reset sequence processing begins by fetching the
normal reset vector. Full stop-mode is left and the MCU is in run mode again.
If the MCU is woken-up by an interrupt and the fast wake-up feature is disabled (FSTWKP = 0 or
SCME = 0), the CRG will also perform a maximum of 50 clock check_windows (see Section 2.4.1.4,
“Clock Quality Checker”). If the clock quality check is successful, the CRG will release all system and
core clocks and will continue with normal operation. If all clock checks within the Timeout-Window are
failing, the CRG will switch to self-clock mode or generate a clock monitor reset (CMRESET) depending
on the setting of the SCME bit.
If the MCU is woken-up by an interrupt and the fast wake-up feature is enabled (FSTWKP = 1 and
SCME = 1), the system will immediately resume operation in self-clock mode (see Section 2.4.1.4, “Clock
Quality Checker”). The SCMIF flag will not be set. 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 CRG will switch all system clocks to
oscillator clock. The SCMIF flag will be set. See application examples in Figure 2-23 and Figure 2-24.
Because the PLL 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
111
Chapter 2 Clocks and Reset Generator (S12CRGV6)
CPU resumes program execution immediately
Instruction
FSTWKP=1
SCME=1 STOP
IRQ Service STOP
IRQ Service
IRQ Service STOP
Interrupt
Interrupt
Interrupt
Power Saving
Oscillator Clock
Oscillator Disabled
PLL Clock
Core Clock
Self-Clock Mode
Figure 2-23. Fast Wake-up from Full Stop Mode: Example 1
.
CPU resumes program execution immediately
Instruction
FSTWKP=1 SCME=1 STOP
IRQ Service FSTWKP=0
SCMIE=1
Freq. Uncritical
Instructions
IRQ Interrupt
Freq. Critical
Instr. Possible
SCM Interrupt
Clock Quality Check
Oscillator Clock
Oscillator Disabled
OSC Startup
PLL Clock
Core Clock
Self-Clock Mode
Figure 2-24. Fast Wake-up from Full Stop Mode: Example 2
MC9S12XDP512 Data Sheet, Rev. 2.21
112
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.5
Resets
This section describes how to reset the CRG, and how the CRG itself controls the reset of the MCU. It
explains all special reset requirements. Since the reset generator for the MCU is part of the CRG, this
section also describes all automatic actions that occur during or as a result of individual reset conditions.
The reset values of registers and signals are provided in Section 2.3, “Memory Map and Register
Definition”. All reset sources are listed in Table 2-14. Refer to MCU specification for related vector
addresses and priorities.
Table 2-14. Reset Summary
2.5.1
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)
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 2-25). Since entry into reset is asynchronous, it does not require a running SYSCLK. However,
the internal reset circuit of the CRG 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 CRG waits for additional 64 SYSCLK cycles and then samples the
RESET pin to determine the originating source. Table 2-15 shows which vector will be fetched.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
113
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Table 2-15. Reset Vector Selection
Sampled RESET Pin
(64 cycles
after release)
Clock Monitor
Reset Pending
COP
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 not include a large
capacitance that would interfere with the ability of this signal to rise to a
valid logic 1 within 64 SYSCLK cycles after the low drive is released.
The internal reset of the MCU remains asserted while the reset generator completes the 192 SYSCLK long
reset sequence. The reset generator circuitry always makes sure the internal reset is deasserted
synchronously after completion of the 192 SYSCLK cycles. In case the RESET pin is externally driven
low for more than these 192 SYSCLK cycles (external reset), the internal reset remains asserted too.
RESET
)(
)(
CRG drives RESET pin low
RESET pin
released
)
)
SYSCLK
(
(
128 + n cycles
Possibly
SYSCLK
not
running
)
(
64 cycles
With n being
min 3 / max 6
cycles depending
on internal
synchronization
delay
Possibly
RESET
driven low
externally
Figure 2-25. RESET Timing
MC9S12XDP512 Data Sheet, Rev. 2.21
114
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.5.2
Clock Monitor Reset
The CRG 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 (see Section 2.3,
“Memory Map and Register Definition”). In detail the CME and the SCME are reset to logical ‘1’ (which
doesn’t change the state of the CME bit, because it has already been set). As a consequence the CRG
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 CRG switches to OSCCLK and
leaves self clock mode. Since the clock quality checker is running in parallel to the reset generator, the
CRG may leave self clock mode while still completing the internal reset sequence. When the reset
sequence is finished, the CRG checks the internally latched state of the clock monitor fail circuit. If a clock
monitor fail is indicated, processing begins by fetching the clock monitor reset vector.
2.5.3
Computer Operating Properly Watchdog (COP) Reset
When COP is enabled, the CRG expects sequential write of 0x_55 and 0x_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 CRG will generate a reset. Also, if any value other than 0x_55 or 0x_AA
is written, the CRG immediately generates a reset. In case windowed COP operation is enabled writes
(0x_55 or 0x_AA) to the ARMCOP register must occur in the last 25% of the selected time-out period. A
premature write the CRG will immediately generate a reset.
As soon as the reset sequence is completed the reset generator checks the reset condition. If no clock
monitor failure is indicated and the latched state of the COP timeout is true, processing begins by fetching
the COP vector.
2.5.4
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 CRG
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 2-26 and Figure 2-27 show the power-up sequence for cases when the RESET pin is tied to VDD
and when the RESET pin is held low.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
115
Chapter 2 Clocks and Reset Generator (S12CRGV6)
Clock Quality Check
(no Self-Clock Mode)
RESET
)(
Internal POR
)(
128 SYSCLK
Internal RESET
)(
64 SYSCLK
Figure 2-26. 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 2-27. RESET Pin Held Low Externally
2.6
Interrupts
The interrupts/reset vectors requested by the CRG are listed in Table 2-16. Refer to MCU specification for
related vector addresses and priorities.
Table 2-16. CRG Interrupt Vectors
2.6.1
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)
Real Time Interrupt
The CRG generates a real time interrupt when the selected interrupt time period elapses. RTI interrupts are
locally disabled by setting the RTIE bit to 0. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
116
Freescale Semiconductor
Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.6.2
PLL Lock Interrupt
The CRG generates a PLL Lock interrupt when the LOCK condition of the PLL 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 0. The PLL 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.
2.6.3
Self Clock Mode Interrupt
The CRG generates a self clock mode interrupt when the SCM condition of the system has changed, either
entered or exited self clock mode. SCM conditions can only change if the self clock mode enable bit
(SCME) is set to 1. 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 2.4.1.4, “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 0. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
117
Chapter 2 Clocks and Reset Generator (S12CRGV6)
MC9S12XDP512 Data Sheet, Rev. 2.21
118
Freescale Semiconductor
Chapter 3
Pierce Oscillator (S12XOSCLCPV1)
3.1
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 (2.5 V nominal) and require the minimum number
of external components. It is designed for optimal start-up margin with typical crystal oscillators.
3.1.1
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
• Low power consumption:
— Operates from 2.5 V (nominal) supply
— Amplitude control limits power
• Clock monitor
3.1.2
Modes of Operation
Two modes of operation exist:
1. Loop controlled Pierce oscillator
2. External square wave mode featuring also full swing Pierce without internal feedback resistor
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
119
Chapter 3 Pierce Oscillator (S12XOSCLCPV1)
3.1.3
Block Diagram
Figure 3-1 shows a block diagram of the XOSC.
Monitor_Failure
Clock
Monitor
OSCCLK
Peak
Detector
Gain Control
VDDPLL = 2.5 V
Rf
XTAL
EXTAL
Figure 3-1. XOSC Block Diagram
3.2
External Signal Description
This section lists and describes the signals that connect off chip
3.2.1
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 be independently bypassed.
3.2.2
EXTAL and XTAL — Input and Output Pins
These pins provide the interface for either a crystal or a 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 from the
MC9S12XDP512 Data Sheet, Rev. 2.21
120
Freescale Semiconductor
Chapter 3 Pierce Oscillator (S12XOSCLCPV1)
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 3-2. Loop Controlled Pierce Oscillator Connections (XCLKS = 1)
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 3-3. Full Swing Pierce Oscillator Connections (XCLKS = 0)
EXTAL
CMOS Compatible
External Oscillator
(VDDPLL Level)
MCU
XTAL
Not Connected
Figure 3-4. External Clock Connections (XCLKS = 0)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
121
Chapter 3 Pierce Oscillator (S12XOSCLCPV1)
3.2.3
XCLKS — Input Signal
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. Refer to the Device Overview chapter for polarity and sampling conditions of the XCLKS
pin. Table 3-1 lists the state coding of the sampled XCLKS signal.
.
Table 3-1. Clock Selection Based on XCLKS
XCLKS
3.3
Description
1
Loop controlled Pierce oscillator selected
0
Full swing Pierce oscillator/external clock selected
Memory Map and Register Definition
The CRG contains the registers and associated bits for controlling and monitoring the oscillator module.
3.4
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 selection of loop controlled
Pierce oscillator or full swing Pierce oscillator/external clock depends on the XCLKS signal which is
sampled during reset. 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.
3.4.1
Gain Control
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.
3.4.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
122
Freescale Semiconductor
Chapter 3 Pierce Oscillator (S12XOSCLCPV1)
3.4.3
Wait Mode Operation
During wait mode, XOSC is not impacted.
3.4.4
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
123
Chapter 3 Pierce Oscillator (S12XOSCLCPV1)
MC9S12XDP512 Data Sheet, Rev. 2.21
124
Freescale Semiconductor
Chapter 4
Analog-to-Digital Converter (ATD10B16CV4)
Block Description
4.1
Introduction
The ATD10B16C is a 16-channel, 10-bit, multiplexed input successive approximation analog-to-digital
converter. Refer to the Electrical Specifications chapter for ATD accuracy.
4.1.1
•
•
•
•
•
•
•
•
•
•
•
•
•
•
4.1.2
Features
8-/10-bit resolution
7 µs, 10-bit single conversion time
Sample buffer amplifier
Programmable sample time
Left/right justified, signed/unsigned result data
External trigger control
Conversion completion interrupt generation
Analog input multiplexer for 16 analog input channels
Analog/digital input pin multiplexing
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
Configurable location for channel wrap around (when converting multiple channels in a sequence)
Modes of Operation
There is software programmable selection between performing single or continuous conversion on a
single channel or multiple channels.
4.1.3
Block Diagram
Refer to Figure 4-1 for a block diagram of the ATD0B16C block.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
125
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Bus Clock
ATD clock
Clock
Prescaler
Trigger
Mux
ETRIG0
ETRIG1
ETRIG2
ATD10B16C
Sequence Complete
Mode and
Timing Control
Interrupt
ETRIG3
(see Device Overview
chapter for availability
and connectivity)
ATDCTL1
ATDDIEN
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
PORTAD
VDDA
VSSA
Successive
Approximation
Register (SAR)
and DAC
VRH
VRL
AN15
AN14
AN13
AN12
AN11
+
AN10
Sample & Hold
AN9
1
1
AN8
AN7
Analog
MUX
Comparator
AN6
AN5
AN4
AN3
AN2
AN1
AN0
Figure 4-1. ATD10B16C Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
126
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.2
External Signal Description
This section lists all inputs to the ATD10B16C block.
4.2.1
ANx (x = 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) — Analog Input
Channel x Pins
This pin serves as the analog input channel x. It can also be configured as general-purpose digital input
and/or external trigger for the ATD conversion.
4.2.2
ETRIG3, ETRIG2, ETRIG1, ETRIG0 — External Trigger Pins
These inputs can be configured to serve as an external trigger for the ATD conversion.
Refer to the Device Overview chapter for availability and connectivity of these inputs.
4.2.3
VRH, VRL — High Reference Voltage Pin, Low Reference Voltage Pin
VRH is the high reference voltage, VRL is the low reference voltage for ATD conversion.
4.2.4
VDDA, VSSA — Analog Circuitry Power Supply Pins
These pins are the power supplies for the analog circuitry of the ATD10B16CV4 block.
4.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the ATD10B16C.
4.3.1
Module Memory Map
Table 4-1 gives an overview of all ATD10B16C registers
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
127
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
.
Table 4-1. ATD10B16CV4 Memory Map
1
Address Offset
Use
Access
0x0000
ATD Control Register 0 (ATDCTL0)
R/W
0x0001
ATD Control Register 1 (ATDCTL1)
R/W
0x0002
ATD Control Register 2 (ATDCTL2)
R/W
0x0003
ATD Control Register 3 (ATDCTL3)
R/W
0x0004
ATD Control Register 4 (ATDCTL4)
R/W
0x0005
ATD Control Register 5 (ATDCTL5)
R/W
R/W
0x0006
ATD Status Register 0 (ATDSTAT0)
0x0007
Unimplemented
0x0008
ATD Test Register 0 (ATDTEST0)1
R
0x0009
ATD Test Register 1 (ATDTEST1)
R/W
0x000A
ATD Status Register 2 (ATDSTAT2)
R
0x000B
ATD Status Register 1 (ATDSTAT1)
R
0x000C
ATD Input Enable Register 0 (ATDDIEN0)
R/W
0x000D
ATD Input Enable Register 1 (ATDDIEN1)
R/W
0x000E
Port Data Register 0 (PORTAD0)
R
0x000F
Port Data Register 1 (PORTAD1)
R
0x0010, 0x0011
ATD Result Register 0 (ATDDR0H, ATDDR0L)
R/W
0x0012, 0x0013
ATD Result Register 1 (ATDDR1H, ATDDR1L)
R/W
0x0014, 0x0015
ATD Result Register 2 (ATDDR2H, ATDDR2L)
R/W
0x0016, 0x0017
ATD Result Register 3 (ATDDR3H, ATDDR3L)
R/W
0x0018, 0x0019
ATD Result Register 4 (ATDDR4H, ATDDR4L)
R/W
0x001A, 0x001B
ATD Result Register 5 (ATDDR5H, ATDDR5L)
R/W
0x001C, 0x001D
ATD Result Register 6 (ATDDR6H, ATDDR6L)
R/W
0x001E, 0x001F
ATD Result Register 7 (ATDDR7H, ATDDR7L)
R/W
0x0020, 0x0021
ATD Result Register 8 (ATDDR8H, ATDDR8L)
R/W
0x0022, 0x0023
ATD Result Register 9 (ATDDR9H, ATDDR9L)
R/W
0x0024, 0x0025
ATD Result Register 10 (ATDDR10H, ATDDR10L)
R/W
0x0026, 0x0027
ATD Result Register 11 (ATDDR11H, ATDDR11L)
R/W
0x0028, 0x0029
ATD Result Register 12 (ATDDR12H, ATDDR12L)
R/W
0x002A, 0x002B
ATD Result Register 13 (ATDDR13H, ATDDR13L)
R/W
0x002C, 0x002D
ATD Result Register 14 (ATDDR14H, ATDDR14L)
R/W
0x002E, 0x002F
ATD Result Register 15 (ATDDR15H, ATDDR15L)
R/W
ATDTEST0 is intended for factory test purposes only.
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
128
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2
Register Descriptions
This section describes in address order all the ATD10B16C registers and their individual bits.
Register
Name
0x0000
ATDCTL0
0x0001
ATDCTL1
R
R
W
W
0x0003
ATDCTL3
W
R
R
W
W
0x0006
ATDSTAT0
W
0x0008
ATDTEST0
R
R
0
0
0
0
0
0
0
AFFC
AWAI
ETRIGLE
ETRIGP
ETRIGE
ASCIE
S8C
S4C
S2C
S1C
FIFO
FRZ1
FRZ0
SRES8
SMP1
SMP0
PRS4
PRS3
PRS2
PRS1
PRS0
DJM
DSGN
SCAN
MULT
CD
CC
CB
CA
ETORF
FIFOR
CC3
CC2
CC1
CC0
ADPU
0
SCF
0
3
2
1
Bit 0
WRAP3
WRAP2
WRAP1
WRAP0
ETRIGCH3 ETRIGCH2 ETRIGCH1 ETRIGCH0
ASCIF
W
R
Unimplemented
W
W
0x000A
ATDSTAT2
W
0x000C
ATDDIEN0
4
R
0x0009
ATDTEST1
0x000B
ATDSTAT1
5
ETRIGSEL
R
0x0005
ATDCTL5
0x0007
Unimplemented
6
W
0x0002
ATDCTL2
0x0004
ATDCTL4
Bit 7
R
R
R
Unimplemented
SC
CCF15
CCF14
CCF13
CCF12
CCF11
CCF10
CCF9
CCF8
CCF7
CCF6
CCF5
CCF4
CCF3
CCF2
CCF1
CCF0
IEN15
IEN14
IEN13
IEN12
IEN11
IEN10
IEN9
IEN8
W
R
W
= Unimplemented or Reserved
u = Unaffected
Figure 4-2. ATD Register Summary
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
129
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Register
Name
0x000D
ATDDIEN1
R
W
0x000E
PORTAD0
W
R
0x000F
PORTAD1
R
Bit 7
6
5
4
3
2
1
Bit 0
IEN7
IEN6
IEN5
IEN4
IEN3
IEN2
IEN1
IEN0
PTAD15
PTAD14
PTAD13
PTAD12
PTAD11
PTAD10
PTAD9
PTAD8
PTAD7
PTAD6
PTAD5
PTAD4
PTAD3
PTAD2
PTAD1
PTAD0
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
BIT 0
u
0
0
0
0
0
0
0
0
0
0
0
0
W
R BIT 9 MSB
BIT 7 MSB
0x0010–0x002F W
ATDDRxH–
ATDDRxL R
BIT 1
u
W
= Unimplemented or Reserved
u = Unaffected
Figure 4-2. ATD Register Summary (continued)
4.3.2.1
ATD Control Register 0 (ATDCTL0)
Writes to this register will abort current conversion sequence but will not start a new sequence.
R
7
6
5
4
0
0
0
0
3
2
1
0
WRAP3
WRAP2
WRAP1
WRAP0
1
1
1
1
W
Reset
0
0
0
0
= Unimplemented or Reserved
Figure 4-3. ATD Control Register 0 (ATDCTL0)
Read: Anytime
Write: Anytime
Table 4-2. 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
multi-channel conversions. The coding is summarized in Table 4-3.
MC9S12XDP512 Data Sheet, Rev. 2.21
130
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-3. Multi-Channel Wrap Around Coding
4.3.2.2
WRAP3
WRAP2
WRAP1
WRAP0
Multiple Channel Conversions
(MULT = 1) Wrap Around to AN0
after Converting
0
0
0
0
Reserved
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
ATD Control Register 1 (ATDCTL1)
Writes to this register will abort current conversion sequence but will not start a new sequence.
7
R
6
5
4
0
0
0
ETRIGSEL
3
2
1
0
ETRIGCH3
ETRIGCH2
ETRIGCH1
ETRIGCH0
1
1
1
1
W
Reset
0
0
0
0
= Unimplemented or Reserved
Figure 4-4. ATD Control Register 1 (ATDCTL1)
Read: Anytime
Write: Anytime
Table 4-4. 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 ETRIG[3:0] inputs. See device specification for availability and connectivity of
ETRIG[3:0] inputs. If ETRIG[3:0] input option is not available, writing a 1 to ETRISEL only sets the bit but has
no effect, that means one of the AD channels (selected by ETRIGCH[3:0]) remains the source for external
trigger. The coding is summarized in Table 4-5.
3:0
External Trigger Channel Select — These bits select one of the AD channels or one of the ETRIG[3:0] inputs
ETRIGCH[3:0] as source for the external trigger. The coding is summarized in Table 4-5.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
131
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-5. External Trigger Channel Select Coding
1
4.3.2.3
ETRIGSEL
ETRIGCH3
ETRIGCH2
ETRIGCH1
ETRIGCH0
External Trigger Source
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 ETRIG[3:0] input option is available (see device specification), else ETRISEL is ignored, that means
external trigger source remains on one of the AD channels selected by ETRIGCH[3:0]
ATD Control Register 2 (ATDCTL2)
This register controls power down, interrupt and external trigger. Writes to this register will abort current
conversion sequence but will not start a new sequence.
MC9S12XDP512 Data Sheet, Rev. 2.21
132
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
7
6
5
4
3
2
1
ADPU
AFFC
AWAI
ETRIGLE
ETRIGP
ETRIGE
ASCIE
0
0
0
0
0
0
0
R
0
ASCIF
W
Reset
0
= Unimplemented or Reserved
Figure 4-5. ATD Control Register 2 (ATDCTL2)
Read: Anytime
Write: Anytime
Table 4-6. ATDCTL2 Field Descriptions
Field
Description
7
ADPU
ATD Power Down — This bit provides on/off control over the ATD10B16C block allowing reduced MCU power
consumption. Because analog electronic is turned off when powered down, the ATD requires a recovery time
period after ADPU bit is enabled.
0 Power down ATD
1 Normal ATD functionality
6
AFFC
ATD Fast Flag Clear All
0 ATD flag clearing operates normally (read the status register ATDSTAT1 before reading the result register
to clear the associate CCF flag).
1 Changes all ATD conversion complete flags to a fast clear sequence. Any access to a result register will
cause the associate CCF flag to clear automatically.
5
AWAI
ATD Power Down in Wait Mode — When entering Wait Mode this bit provides on/off control over the
ATD10B16C block allowing reduced MCU power. Because analog electronic is turned off when powered down,
the ATD requires a recovery time period after exit from Wait mode.
0 ATD continues to run in Wait mode
1 Halt conversion and power down ATD during Wait mode
After exiting Wait mode with an interrupt conversion will resume. But due to the recovery time the result of
this conversion should be ignored.
4
ETRIGLE
External Trigger Level/Edge Control — This bit controls the sensitivity of the external trigger signal. See
Table 4-7 for details.
3
ETRIGP
External Trigger Polarity — This bit controls the polarity of the external trigger signal. See Table 4-7 for
details.
2
ETRIGE
External Trigger Mode Enable — This bit enables the external trigger on one of the AD channels or one of
the ETRIG[3:0] inputs as described in Table 4-5. 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.
0 Disable external trigger
1 Enable external trigger
1
ASCIE
ATD Sequence Complete Interrupt Enable
0 ATD Sequence Complete interrupt requests are disabled.
1 ATD Interrupt will be requested whenever ASCIF = 1 is set.
0
ASCIF
ATD Sequence Complete Interrupt Flag — If ASCIE = 1 the ASCIF flag equals the SCF flag (see
Section 4.3.2.7, “ATD Status Register 0 (ATDSTAT0)”), else ASCIF reads zero. Writes have no effect.
0 No ATD interrupt occurred
1 ATD sequence complete interrupt pending
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
133
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-7. External Trigger Configurations
ETRIGLE
ETRIGP
External Trigger Sensitivity
0
0
Falling Edge
0
1
Ring Edge
1
0
Low Level
1
1
High Level
MC9S12XDP512 Data Sheet, Rev. 2.21
134
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.4
ATD Control Register 3 (ATDCTL3)
This register controls the conversion sequence length, FIFO for results registers and behavior in Freeze
Mode. Writes to this register will abort current conversion sequence but will not start a new sequence.
7
R
6
5
4
3
2
1
0
S8C
S4C
S2C
S1C
FIFO
FRZ1
FRZ0
0
1
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 4-6. ATD Control Register 3 (ATDCTL3)
Read: Anytime
Write: Anytime
Table 4-8. ATDCTL3 Field Descriptions
Field
Description
6
S8C
Conversion Sequence Length — This bit controls the number of conversions per sequence. Table 4-9 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
5
S4C
Conversion Sequence Length — This bit controls the number of conversions per sequence. Table 4-9 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
4
S2C
Conversion Sequence Length — This bit controls the number of conversions per sequence. Table 4-9 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
3
S1C
Conversion Sequence Length — This bit controls the number of conversions per sequence. Table 4-9 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
135
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-8. ATDCTL3 Field Descriptions (continued)
Field
Description
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, the second result in the second result register, 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 by write to an ATDCTL register (ATDCTL5-0) 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).
Finally, 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.
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 4-10. 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.
Table 4-9. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
136
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-10. ATD Behavior in Freeze Mode (Breakpoint)
FRZ1
FRZ0
Behavior in Freeze Mode
0
0
Continue conversion
0
1
Reserved
1
0
Finish current conversion, then freeze
1
1
Freeze Immediately
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
137
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.5
ATD Control Register 4 (ATDCTL4)
This register selects the conversion clock frequency, the length of the second phase of the sample time and
the resolution of the A/D conversion (i.e., 8-bits or 10-bits). Writes to this register will abort current
conversion sequence but will not start a new sequence.
7
6
5
4
3
2
1
0
SRES8
SMP1
SMP0
PRS4
PRS3
PRS2
PRS1
PRS0
0
0
0
0
0
1
0
1
R
W
Reset
Figure 4-7. ATD Control Register 4 (ATDCTL4)
Read: Anytime
Write: Anytime
Table 4-11. ATDCTL4 Field Descriptions
Field
Description
7
SRES8
A/D Resolution Select — This bit selects the resolution of A/D conversion results as either 8 or 10 bits. The
A/D converter has an accuracy of 10 bits. However, if low resolution is required, the conversion can be speeded
up by selecting 8-bit resolution.
0 10 bit resolution
1 8 bit resolution
6:5
SMP[1:0]
Sample Time Select —These two bits select the length of the second phase 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). The sample time consists of two phases. The first phase is two ATD conversion clock cycles
long and transfers the sample quickly (via the buffer amplifier) onto the A/D machine’s storage node. The
second phase attaches the external analog signal directly to the storage node for final charging and high
accuracy. Table 4-12 lists the lengths available for the second sample phase.
4:0
PRS[4:0]
ATD Clock Prescaler — These 5 bits are the binary value prescaler value PRS. The ATD conversion clock
frequency is calculated as follows:
[ BusClock ]
ATDclock = -------------------------------- × 0.5
[ PRS + 1 ]
Note: The maximum ATD conversion clock frequency is half the bus clock. The default (after reset) prescaler
value is 5 which results in a default ATD conversion clock frequency that is bus clock divided by 12.
Table 4-13 illustrates the divide-by operation and the appropriate range of the bus clock.
Table 4-12. Sample Time Select
SMP1
SMP0
Length of 2nd Phase of Sample Time
0
0
2 A/D conversion clock periods
0
1
4 A/D conversion clock periods
1
0
8 A/D conversion clock periods
1
1
16 A/D conversion clock periods
MC9S12XDP512 Data Sheet, Rev. 2.21
138
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-13. Clock Prescaler Values
Prescale Value
Total Divisor
Value
Max. Bus Clock1
Min. Bus Clock2
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111
Divide by 2
Divide by 4
Divide by 6
Divide by 8
Divide by 10
Divide by 12
Divide by 14
Divide by 16
Divide by 18
Divide by 20
Divide by 22
Divide by 24
Divide by 26
Divide by 28
Divide by 30
Divide by 32
Divide by 34
Divide by 36
Divide by 38
Divide by 40
Divide by 42
Divide by 44
Divide by 46
Divide by 48
Divide by 50
Divide by 52
Divide by 54
Divide by 56
Divide by 58
Divide by 60
Divide by 62
Divide by 64
4 MHz
8 MHz
12 MHz
16 MHz
20 MHz
24 MHz
28 MHz
32 MHz
36 MHz
40 MHz
44 MHz
48 MHz
52 MHz
56 MHz
60 MHz
64 MHz
68 MHz
72 MHz
76 MHz
80 MHz
84 MHz
88 MHz
92 MHz
96 MHz
100 MHz
104 MHz
108 MHz
112 MHz
116 MHz
120 MHz
124 MHz
128 MHz
1 MHz
2 MHz
3 MHz
4 MHz
5 MHz
6 MHz
7 MHz
8 MHz
9 MHz
10 MHz
11 MHz
12 MHz
13 MHz
14 MHz
15 MHz
16 MHz
17 MHz
18 MHz
19 MHz
20 MHz
21 MHz
22 MHz
23 MHz
24 MHz
25 MHz
26 MHz
27 MHz
28 MHz
29 MHz
30 MHz
31 MHz
32 MHz
1
Maximum ATD conversion clock frequency is 2 MHz. The maximum allowed bus clock frequency is
shown in this column.
2
Minimum ATD conversion clock frequency is 500 kHz. The minimum allowed bus clock frequency is
shown in this column.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
139
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.6
ATD Control Register 5 (ATDCTL5)
This register selects the type of conversion sequence and the analog input channels sampled. 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.
7
6
5
4
3
2
1
0
DJM
DSGN
SCAN
MULT
CD
CC
CB
CA
0
0
0
0
0
0
0
0
R
W
Reset
Figure 4-8. ATD Control Register 5 (ATDCTL5)
Read: Anytime
Write: Anytime
Table 4-14. ATDCTL5 Field Descriptions
Field
Description
7
DJM
Result Register Data Justification — This bit controls justification of conversion data in the result registers.
See Section 4.3.2.16, “ATD Conversion Result Registers (ATDDRx)” for details.
0 Left justified data in the result registers.
1 Right justified data in the result registers.
6
DSGN
Result Register Data Signed or Unsigned Representation — This bit selects between signed and unsigned
conversion data representation in the result registers. Signed data is represented as 2’s complement. Signed
data is not available in right justification. See <st-bold>4.3.2.16 ATD Conversion Result Registers (ATDDRx)
for details.
0 Unsigned data representation in the result registers.
1 Signed data representation in the result registers.
Table 4-15 summarizes the result data formats available and how they are set up using the control bits.
Table 4-16 illustrates the difference between the signed and unsigned, left justified output codes for an input
signal range between 0 and 5.12 Volts.
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
each trigger event starts a single conversion sequence.
0 Single conversion sequence
1 Continuous conversion sequences (scan mode)
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 (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
MC9S12XDP512 Data Sheet, Rev. 2.21
140
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-14. ATDCTL5 Field Descriptions (continued)
Field
Description
3:0
C[D:A}
Analog Input Channel Select Code — These bits select the analog input channel(s) whose signals are
sampled and converted to digital codes. Table 4-17 lists the coding used to select the various analog input
channels.
In the case of single channel conversions (MULT = 0), this selection code specified the channel to be examined.
In the case of multiple channel conversions (MULT = 1), this selection code represents 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 WRAP[3:0] in ATDCTL0). In case starting with a channel number higher than the one defined by
WRAP[3:0] the first wrap around will be AN15 to AN0.
Table 4-15. Available Result Data Formats.
SRES8
DJM
DSGN
Result Data Formats
Description and Bus Bit Mapping
1
0
0
8-bit / left justified / unsigned — bits 15:8
1
0
1
8-bit / left justified / signed — bits 15:8
1
1
X
8-bit / right justified / unsigned — bits 7:0
0
0
0
10-bit / left justified / unsigned — bits 15:6
0
0
1
10-bit / left justified / signed -— bits 15:6
0
1
X
10-bit / right justified / unsigned — bits 9:0
Table 4-16. Left Justified, Signed and Unsigned ATD Output Codes.
Input Signal
VRL = 0 Volts
VRH = 5.12 Volts
Signed
8-Bit Codes
Unsigned
8-Bit Codes
Signed
10-Bit Codes
Unsigned
10-Bit Codes
5.120 Volts
7F
FF
7FC0
FFC0
5.100
7F
FF
7F00
FF00
5.080
7E
FE
7E00
FE00
2.580
01
81
0100
8100
2.560
00
80
0000
8000
2.540
FF
7F
FF00
7F00
0.020
81
01
8100
0100
0.000
80
00
8000
0000
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
141
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-17. Analog Input Channel Select Coding
CD
CC
CB
CA
Analog Input
Channel
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
MC9S12XDP512 Data Sheet, Rev. 2.21
142
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.7
ATD Status Register 0 (ATDSTAT0)
This read-only register contains the Sequence Complete Flag, overrun flags for external trigger and FIFO
mode, and the conversion counter.
7
6
R
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 4-9. ATD Status Register 0 (ATDSTAT0)
Read: Anytime
Write: Anytime (No effect on CC[3:0])
Table 4-18. ATDSTAT0 Field Descriptions
Field
7
SCF
5
ETORF
Description
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:
• Write “1” to SCF
• Write to ATDCTL5 (a new conversion sequence is started)
• If AFFC = 1 and read of a result register
0 Conversion sequence not completed
1 Conversion sequence has completed
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:
• Write “1” to ETORF
• Write to ATDCTL0,1,2,3,4 (a conversion sequence is aborted)
• 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
143
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-18. ATDSTAT0 Field Descriptions (continued)
Field
Description
4
FIFOR
FIFO 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:
• Write “1” to FIFOR
• Start a new conversion sequence (write to ATDCTL5 or external trigger)
0 No over run has occurred
1 Overrun condition exists (result register has been written while associated CCFx flag remained set)
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. For example, 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 by write to an ATDCTL register (ATDCTL5-0) clears the
conversion counter even if FIFO=1.
MC9S12XDP512 Data Sheet, Rev. 2.21
144
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.8
R
Reserved Register 0 (ATDTEST0)
7
6
5
4
3
2
1
0
u
u
u
u
u
u
u
u
1
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
u = Unaffected
Figure 4-10. Reserved Register 0 (ATDTEST0)
Read: Anytime, returns unpredictable values
Write: Anytime in special modes, unimplemented in normal modes
NOTE
Writing to this register when in special modes can alter functionality.
4.3.2.9
ATD Test Register 1 (ATDTEST1)
This register contains the SC bit used to enable special channel conversions.
R
7
6
5
4
3
2
1
u
u
u
u
u
u
u
0
SC
W
Reset
0
0
0
0
0
= Unimplemented or Reserved
0
0
0
u = Unaffected
Figure 4-11. Reserved Register 1 (ATDTEST1)
Read: Anytime, returns unpredictable values for bit 7 and bit 6
Write: Anytime
NOTE
Writing to this register when in special modes can alter functionality.
Table 4-19. ATDTEST1 Field Descriptions
Field
Description
0
SC
Special Channel Conversion Bit — If this bit is set, then special channel conversion can be selected using
CC, CB, and CA of ATDCTL5. Table 4-20 lists the coding.
0 Special channel conversions disabled
1 Special channel conversions enabled
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
145
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
Table 4-20. Special Channel Select Coding
SC
CD
CC
CB
CA
Analog Input Channel
1
0
0
X
X
Reserved
1
0
1
0
0
VRH
1
0
1
0
1
VRL
1
0
1
1
0
(VRH+VRL) / 2
1
0
1
1
1
Reserved
1
1
X
X
X
Reserved
4.3.2.10
ATD Status Register 2 (ATDSTAT2)
This read-only register contains the Conversion Complete Flags CCF15 to CCF8.
R
7
6
5
4
3
2
1
0
CCF15
CCF14
CCF13
CCF12
CCF11
CCF10
CCF9
CCF8
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 4-12. ATD Status Register 2 (ATDSTAT2)
Read: Anytime
Write: Anytime, no effect
Table 4-21. ATDSTAT2 Field Descriptions
Field
Description
7:0
CCF[15:8]
Conversion Complete Flag Bits — A conversion complete flag is set at the end of each conversion in a
conversion sequence. The flags are associated with the conversion position in a sequence (and also the result
register number). Therefore, CCF8 is set when the ninth conversion in a sequence is complete and the result
is available in result register ATDDR8; CCF9 is set when the tenth conversion in a sequence is complete and
the result is available in ATDDR9, and so forth. A flag CCFx (x = 15, 14, 13, 12, 11, 10, 9, 8) is cleared when
one of the following occurs:
• Write to ATDCTL5 (a new conversion sequence is started)
• If AFFC = 0 and read of ATDSTAT2 followed by read of result register ATDDRx
• If AFFC = 1 and read of result register ATDDRx
In case of a concurrent set and clear on CCFx: The clearing by method A) will overwrite the set. The clearing
by methods B) or C) will be overwritten by the set.
0 Conversion number x not completed
1 Conversion number x has completed, result ready in ATDDRx
MC9S12XDP512 Data Sheet, Rev. 2.21
146
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.11
ATD Status Register 1 (ATDSTAT1)
This read-only register contains the Conversion Complete Flags CCF7 to CCF0
R
7
6
5
4
3
2
1
0
CCF7
CCF6
CCF5
CCF4
CCF3
CCF2
CCF1
CCF0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 4-13. ATD Status Register 1 (ATDSTAT1)
Read: Anytime
Write: Anytime, no effect
Table 4-22. ATDSTAT1 Field Descriptions
Field
Description
7:0
CCF[7:0]
Conversion Complete Flag Bits — A conversion complete flag is set at the end of each conversion in a
conversion sequence. The flags are associated with the conversion position in a sequence (and also the result
register number). Therefore, CCF0 is set when the first conversion in a sequence is complete and the result is
available in result register ATDDR0; CCF1 is set when the second conversion in a sequence is complete and
the result is available in ATDDR1, and so forth. A CCF flag is cleared when one of the following occurs:
• Write to ATDCTL5 (a new conversion sequence is started)
• If AFFC = 0 and read of ATDSTAT1 followed by read of result register ATDDRx
• If AFFC = 1 and read of result register ATDDRx
In case of a concurrent set and clear on CCFx: The clearing by method A) will overwrite the set. The clearing
by methods B) or C) will be overwritten by the set.
Conversion number x not completed
Conversion number x has completed, result ready in ATDDRx
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
147
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.12
ATD Input Enable Register 0 (ATDDIEN0)
7
6
5
4
3
2
1
0
IEN15
IEN14
IEN13
IEN12
IEN11
IEN10
IEN9
IEN8
0
0
0
0
0
0
0
0
R
W
Reset
Figure 4-14. ATD Input Enable Register 0 (ATDDIEN0)
Read: Anytime
Write: anytime
Table 4-23. ATDDIEN0 Field Descriptions
Field
Description
7:0
IEN[15:8]
ATD Digital Input Enable on Channel Bits — This bit controls the digital input buffer from the analog input
pin (ANx) to PTADx data register.
0 Disable digital input buffer to PTADx
1 Enable digital input buffer to PTADx.
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.
4.3.2.13
ATD Input Enable Register 1 (ATDDIEN1)
7
6
5
4
3
2
1
0
IEN7
IEN6
IEN5
IEN4
IEN3
IEN2
IEN1
IEN0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 4-15. ATD Input Enable Register 1 (ATDDIEN1)
Read: Anytime
Write: Anytime
Table 4-24. ATDDIEN1 Field Descriptions
Field
Description
7:0
IEN[7:0]
ATD Digital Input Enable on Channel Bits — This bit controls the digital input buffer from the analog input
pin (ANx) to PTADx data register.
0 Disable digital input buffer to PTADx
1 Enable digital input buffer to PTADx.
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
148
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.14
Port Data Register 0 (PORTAD0)
The data port associated with the ATD is input-only. The port pins are shared with the analog A/D inputs
AN[15:8].
R
7
6
5
4
3
2
1
0
PTAD15
PTAD14
PTAD13
PTAD12
PTAD11
PTAD10
PTAD9
PTAD8
1
1
1
1
1
1
1
1
AN15
AN14
AN13
AN12
AN11
AN10
AN9
AN8
W
Reset
Pin
Function
= Unimplemented or Reserved
Figure 4-16. Port Data Register 0 (PORTAD0)
Read: Anytime
Write: Anytime, no effect
The A/D input channels may be used for general-purpose digital input.
Table 4-25. PORTAD0 Field Descriptions
Field
Description
7:0
PTAD[15:8]
A/D Channel x (ANx) Digital Input Bits— If the digital input buffer on the ANx pin is enabled (IENx = 1) or
channel x is enabled as external trigger (ETRIGE = 1, ETRIGCH[3-0] = x, ETRIGSEL = 0) read returns the
logic level on ANx pin (signal potentials not meeting VIL or VIH specifications will have an indeterminate value)).
If the digital input buffers are disabled (IENx = 0) and channel x is not enabled as external trigger, read returns
a “1”.
Reset sets all PORTAD0 bits to “1”.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
149
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.15
Port Data Register 1 (PORTAD1)
The data port associated with the ATD is input-only. The port pins are shared with the analog A/D inputs
AN7-0.
R
7
6
5
4
3
2
1
0
PTAD7
PTAD6
PTAD5
PTAD4
PTAD3
PTAD2
PTAD1
PTAD0
1
1
1
1
1
1
1
1
AN 7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
W
Reset
Pin
Function
= Unimplemented or Reserved
Figure 4-17. Port Data Register 1 (PORTAD1)
Read: Anytime
Write: Anytime, no effect
The A/D input channels may be used for general-purpose digital input.
Table 4-26. PORTAD1 Field Descriptions
Field
Description
7:0
PTAD[7:8]
A/D Channel x (ANx) Digital Input Bits — If the digital input buffer on the ANx pin is enabled (IENx=1) or
channel x is enabled as external trigger (ETRIGE = 1, ETRIGCH[3-0] = x, ETRIGSEL = 0) read returns the
logic level on ANx pin (signal potentials not meeting VIL or VIH specifications will have an indeterminate value)).
If the digital input buffers are disabled (IENx = 0) and channel x is not enabled as external trigger, read returns
a “1”.
Reset sets all PORTAD1 bits to “1”.
MC9S12XDP512 Data Sheet, Rev. 2.21
150
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.16
ATD Conversion Result Registers (ATDDRx)
The A/D conversion results are stored in 16 read-only result registers. The result data is formatted in the
result registers bases on two criteria. First there is left and right justification; this selection is made using
the DJM control bit in ATDCTL5. Second there is signed and unsigned data; this selection is made using
the DSGN control bit in ATDCTL5. Signed data is stored in 2’s complement format and only exists in left
justified format. Signed data selected for right justified format is ignored.
Read: Anytime
Write: Anytime in special mode, unimplemented in normal modes
4.3.2.16.1
Left Justified Result Data
7
R (10-BIT) BIT 9 MSB
R (8-BIT) BIT 7 MSB
6
5
4
3
2
1
0
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 4-18. Left Justified, ATD Conversion Result Register x, High Byte (ATDDRxH)
R (10-BIT)
R (8-BIT)
7
6
5
4
3
2
1
0
BIT 1
u
BIT 0
u
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
u = Unaffected
Figure 4-19. Left Justified, ATD Conversion Result Register x, Low Byte (ATDDRxL)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
151
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.3.2.16.2
R (10-BIT)
R (8-BIT)
Right Justified Result Data
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 4-20. Right Justified, ATD Conversion Result Register x, High Byte (ATDDRxH)
7
R (10-BIT)
BIT 7
R (8-BIT) BIT 7 MSB
6
5
4
3
2
1
0
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 4-21. Right Justified, ATD Conversion Result Register x, Low Byte (ATDDRxL)
4.4
Functional Description
The ATD10B16C is structured in an analog and a digital sub-block.
4.4.1
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.
4.4.1.1
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.
The sample process uses a two stage approach. During the first stage, the sample amplifier is used to
quickly charge the storage node.The second stage connects the input directly to the storage node to
complete the sample for high accuracy.
When not sampling, the sample and hold machine disables its own clocks. The analog electronics continue
drawing their quiescent current. The power down (ADPU) bit must be set to disable both the digital clocks
and the analog power consumption.
The input analog signals are unipolar and must fall within the potential range of VSSA to VDDA.
MC9S12XDP512 Data Sheet, Rev. 2.21
152
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.4.1.2
Analog Input Multiplexer
The analog input multiplexer connects one of the 16 external analog input channels to the sample and hold
machine.
4.4.1.3
Sample Buffer Amplifier
The sample amplifier is used to buffer the input analog signal so that the storage node can be quickly
charged to the sample potential.
4.4.1.4
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 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 disables its own clocks. The analog electronics continue drawing
quiescent current. The power down (ADPU) bit must be set to disable both the digital clocks and the analog
power consumption.
Only analog input signals within the potential range of VRL to VRH (A/D reference potentials) will result
in a non-railed digital output codes.
4.4.2
Digital Sub-Block
This subsection explains some of the digital features in more detail. See register descriptions for all details.
4.4.2.1
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
be edge or level sensitive with polarity control. Table 4-27 gives a brief description of the different
combinations of control bits and their effect on the external trigger function.
Table 4-27. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
153
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
In either level or edge triggered modes, the first conversion begins when the trigger is received. In both
cases, the maximum latency time is one bus clock cycle plus any skew or delay introduced by the trigger
circuitry.
After 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 remains asserted
in level mode while a sequence is completing, another sequence will be triggered immediately.
4.4.2.2
General-Purpose Digital Input Port Operation
The input channel pins can be multiplexed between analog and digital data. As analog inputs, they are
multiplexed and sampled to supply signals to the A/D converter. As digital inputs, they supply external
input data that can be accessed through the digital port registers (PORTAD0 & PORTAD1) (input-only).
The analog/digital multiplex operation is performed in the input pads. The input pad is always connected
to the analog inputs of the ATD10B16C. The input pad signal is buffered to the digital port registers. This
buffer can be turned on or off with the ATDDIEN0 & ATDDIEN1 register. This is important so that the
buffer does not draw excess current when analog potentials are presented at its input.
4.4.3
Operation in Low Power Modes
The ATD10B16C can be configured for lower MCU power consumption in three different ways:
• Stop Mode
Stop Mode: This halts A/D conversion. Exit from Stop mode will resume A/D conversion, But due
to the recovery time the result of this conversion should be ignored.
Entering stop mode causes all clocks to halt and thus the system is placed in a minimum power
standby mode. This halts any conversion sequence in progress. During recovery from stop mode,
there must be a minimum delay for the stop recovery time tSR before initiating a new ATD
conversion sequence.
• Wait Mode
Wait Mode with AWAI = 1: This halts A/D conversion. Exit from Wait mode will resume A/D
conversion, but due to the recovery time the result of this conversion should be ignored.
Entering wait mode, the ATD conversion either continues or halts for low power depending on the
logical value of the AWAIT bit.
• Freeze Mode
Writing ADPU = 0 (Note that all ATD registers remain accessible.): This aborts any A/D
conversion in progress.
In freeze mode, the ATD10B16C will behave according to the logical values of the FRZ1 and FRZ0
bits. This is useful for debugging and emulation.
NOTE
The reset value for the ADPU bit is zero. Therefore, when this module is
reset, it is reset into the power down state.
MC9S12XDP512 Data Sheet, Rev. 2.21
154
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
4.5
Resets
At reset the ATD10B16C is in a power down state. The reset state of each individual bit is listed within
Section 4.3, “Memory Map and Register Definition,” which details the registers and their bit fields.
4.6
Interrupts
The interrupt requested by the ATD10B16C is listed in Table 4-28. Refer to MCU specification for related
vector address and priority.
Table 4-28. ATD Interrupt Vectors
Interrupt Source
Sequence Complete Interrupt
CCR Mask
Local Enable
I bit
ASCIE in ATDCTL2
See Section 4.3.2, “Register Descriptions,” for further details.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
155
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
MC9S12XDP512 Data Sheet, Rev. 2.21
156
Freescale Semiconductor
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
157
Chapter 4 Analog-to-Digital Converter (ATD10B16CV4) Block Description
MC9S12XDP512 Data Sheet, Rev. 2.21
158
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.1
Introduction
The ATD10B8C is an 8-channel, 10-bit, multiplexed input successive approximation analog-to-digital
converter. Refer to device electrical specifications for ATD accuracy.
5.1.1
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Features
8/10-bit resolution
7 µsec, 10-bit single conversion time
Sample buffer amplifier
Programmable sample time
Left/right justified, signed/unsigned result data
External trigger control
Conversion completion interrupt generation
Analog input multiplexer for 8 analog input channels
Analog/digital input pin multiplexing
1-to-8 conversion sequence lengths
Continuous conversion mode
Multiple channel scans
Configurable external trigger functionality on any AD channel or any of four additional external
trigger inputs. The four additional trigger inputs can be chip external or internal. Refer to the device
overview chapter for availability and connectivity.
Configurable location for channel wrap around (when converting multiple channels in a sequence).
5.1.2
5.1.2.1
Modes of Operation
Conversion Modes
There is software programmable selection between performing single or continuous conversion on a single
channel or multiple channels.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
159
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.1.2.2
•
•
•
5.1.3
MCU Operating Modes
Stop mode
Entering stop mode causes all clocks to halt and thus the system is placed in a minimum power
standby mode. This aborts any conversion sequence in progress. During recovery from stop mode,
there must be a minimum delay for the stop recovery time tSR before initiating a new ATD
conversion sequence.
Wait mode
Entering wait mode the ATD conversion either continues or aborts for low power depending on the
logical value of the AWAIT bit.
Freeze mode
In freeze mode the ATD will behave according to the logical values of the FRZ1 and FRZ0 bits.
This is useful for debugging and emulation.
Block Diagram
Figure 5-1 shows a block diagram of the ATD.
5.2
External Signal Description
This section lists all inputs to the ATD block.
5.2.1
ANx (x = 7, 6, 5, 4, 3, 2, 1, 0) — Analog Input Pin
This pin serves as the analog input channel x. It can also be configured as general purpose digital port pin
and/or external trigger for the ATD conversion.
5.2.2
ETRIG3, ETRIG2, ETRIG1, and ETRIG0 — External Trigger Pins
These inputs can be configured to serve as an external trigger for the ATD conversion.
Refer to the device overview chapter for availability and connectivity of these inputs.
5.2.3
VRH and VRL — High and Low Reference Voltage Pins
VRH is the high reference voltage and VRL is the low reference voltage for ATD conversion.
5.2.4
VDDA and VSSA — Power Supply Pins
These pins are the power supplies for the analog circuitry of the ATD block.
MC9S12XDP512 Data Sheet, Rev. 2.21
160
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Bus Clock
ETRIG0
ETRIG1
ETRIG2
Clock
Prescaler
ATD clock
Trigger
Mux
ATD10B8C
Sequence Complete
Mode and
Timing Control
Interrupt
ETRIG3
(See Device Overview
chapter for availability
and connectivity)
ATDDIEN
ATDCTL1
PORTAD
Results
ATD 0
ATD 1
ATD 2
ATD 3
ATD 4
ATD 5
ATD 6
ATD 7
VDDA
VSSA
Successive
Approximation
Register (SAR)
and DAC
VRH
VRL
AN7
AN6
+
AN5
Sample & Hold
AN4
1
1
AN3
Analog
AN2
–
Comparator
MUX
AN1
AN0
Figure 5-1. ATD Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
161
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the ATD.
5.3.1
Module Memory Map
Figure 5-2 gives an overview of all ATD 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.
5.3.2
Register Descriptions
This section describes in address order all the ATD registers and their individual bits.
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
WRAP2
WRAP1
WRAP0
0
0
0
0
AFFC
AWAI
ETRIGLE
ETRIGP
ETRIGE
ASCIE
S8C
S4C
S2C
S1C
FIFO
FRZ1
FRZ0
PRS3
PRS2
PRS1
PRS0
CC
CB
CA
0
CC2
CC1
CC0
U
ATDCTL0
R
W
ATDCTL1
R
ETRIGSEL
W
ATDCTL2
R
W
ATDCTL3
R
W
ATDCTL4
R
W
SRES8
SMP1
SMP0
PRS4
ATDCTL5
R
W
DJM
DSGN
SCAN
MULT
ATDSTAT0
R
W
SCF
ETORF
FIFOR
Unimplemente
d
R
W
ATDTEST0
R
W
U
U
U
U
U
U
U
ATDTEST1
R
W
U
U
0
0
0
0
0
ADPU
0
0
ETRIGCH2 ETRIGCH1 ETRIGCH0
0
ASCIF
SC
= Unimplemented or Reserved
Figure 5-2. ATD Register Summary (Sheet 1 of 5)
MC9S12XDP512 Data Sheet, Rev. 2.21
162
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Register
Name
Unimplemente
d
R
W
ATDSTAT1
R
W
Unimplemente
d
R
W
ATDDIEN
R
W
Unimplemente
d
R
W
PORTAD
R
W
Bit 7
6
5
4
3
2
1
Bit 0
CCF7
CCF6
CCF5
CCF4
CCF3
CCF2
CCF1
CCF0
IEN7
IEN6
IEN5
IEN4
IEN3
IEN2
IEN1
IEN0
PTAD7
PTAD6
PTAD5
PTAD4
PTAD3
PTAD2
PTAD1
PTAD0
Left Justified Result Data
Note: The read portion of the left justified result data registers has been divided to show the bit position when reading 10-bit and
8-bit conversion data. For more detailed information refer to Section 5.3.2.13, “ATD Conversion Result Registers
(ATDDRx)”.
ATDDR0H
10-BIT BIT 9 MSB
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
8-BIT BIT 7 MSB
W
ATDDR0L
10-BIT
8-BIT
W
ATDDR1H
BIT 1
U
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
10-BIT BIT 9 MSB
8-BIT BIT 7 MSB
W
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
ATDDR1L
10-BIT
8-BIT
W
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
ATDDR2H
10-BIT BIT 9 MSB
8-BIT BIT 7 MSB
W
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
ATDDR2L
10-BIT
8-BIT
W
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
ATDDR3H
10-BIT BIT 9 MSB
8-BIT BIT 7 MSB
W
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
BIT 1
U
BIT 1
U
= Unimplemented or Reserved
Figure 5-2. ATD Register Summary (Sheet 2 of 5)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
163
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
BIT 1
U
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
ATDDR3L
10-BIT
8-BIT
W
ATDDR4H
10-BIT BIT 9 MSB
8-BIT BIT 7 MSB
W
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
ATDDR4L
10-BIT
8-BIT
W
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
ATDD45H
10-BIT BIT 9 MSB
8-BIT BIT 7 MSB
W
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
ATDD45L
10-BIT
8-BIT
W
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
ATDD46H
10-BIT BIT 9 MSB
8-BIT BIT 7 MSB
W
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
ATDDR6L
10-BIT
8-BIT
W
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
ATDD47H
10-BIT BIT 9 MSB
8-BIT BIT 7 MSB
W
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
ATDD47L
10-BIT
8-BIT
W
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
BIT 1
U
BIT 1
U
BIT 1
U
BIT 1
U
Right Justified Result Data
Note: The read portion of the right justified result data registers has been divided to show the bit position when reading 10-bit
and 8-bit conversion data. For more detailed information refer to Section 5.3.2.13, “ATD Conversion Result Registers
(ATDDRx)”.
ATDDR0H
10-BIT
0
0
0
0
0
0
BIT 9 MSB
BIT 8
0
0
0
0
0
0
0
0
8-BIT
W
ATDDR0L
10-BIT
BIT 7
8-BIT BIT 7 MSB
W
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
= Unimplemented or Reserved
Figure 5-2. ATD Register Summary (Sheet 3 of 5)
MC9S12XDP512 Data Sheet, Rev. 2.21
164
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
ATDDR1H
10-BIT
8-BIT
W
ATDDR1L
10-BIT
BIT 7
8-BIT BIT 7 MSB
W
ATDDR2H
10-BIT
8-BIT
W
ATDDR2L
10-BIT
BIT 7
8-BIT BIT 7 MSB
W
ATDDR3H
10-BIT
8-BIT
W
ATDDR3L
10-BIT
BIT 7
8-BIT BIT 7 MSB
W
ATDDR4H
10-BIT
8-BIT
W
ATDDR4L
10-BIT
BIT 7
8-BIT BIT 7 MSB
W
ATDD45H
10-BIT
8-BIT
W
ATDD45L
10-BIT
BIT 7
8-BIT BIT 7 MSB
W
ATDD46H
10-BIT
8-BIT
W
ATDDR6L
10-BIT
BIT 7
8-BIT BIT 7 MSB
W
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 5-2. ATD Register Summary (Sheet 4 of 5)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
165
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Register
Name
Bit 7
6
5
4
3
2
1
Bit 0
ATDD47H
10-BIT
8-BIT
W
0
0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
ATDD47L
10-BIT
BIT 7
BIT 7 MSB
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
8-BIT
= Unimplemented or Reserved
Figure 5-2. ATD Register Summary (Sheet 5 of 5)
5.3.2.1
ATD Control Register 0 (ATDCTL0)
Writes to this register will abort current conversion sequence but will not start a new sequence.
R
7
6
5
4
3
0
0
0
0
0
0
0
0
0
0
W
Reset
2
1
0
WRAP2
WRAP1
WRAP0
1
1
1
= Unimplemented or Reserved
Figure 5-3. ATD Control Register 0 (ATDCTL0)
Read: Anytime
Write: Anytime
Table 5-1. ATDCTL0 Field Descriptions
Field
2–0
WRAP[2:0]
Description
Wrap Around Channel Select Bits — These bits determine the channel for wrap around when doing
multi-channel conversions. The coding is summarized in Table 5-2.
Table 5-2. Multi-Channel Wrap Around Coding
WRAP2
WRAP1
WRAP0
Multiple Channel Conversions (MULT = 1)
Wrap Around to AN0 after Converting
0
0
0
Reserved
0
0
1
AN1
0
1
0
AN2
0
1
1
AN3
1
0
0
AN4
1
0
1
AN5
1
1
0
AN6
1
1
1
AN7
MC9S12XDP512 Data Sheet, Rev. 2.21
166
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.2
ATD Control Register 1 (ATDCTL1)
Writes to this register will abort current conversion sequence but will not start a new sequence.
7
R
W
ETRIGSEL
Reset
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
ETRIGCH2
ETRIGCH1
ETRIGCH0
1
1
1
= Unimplemented or Reserved
Figure 5-4. ATD Control Register 1 (ATDCTL1)
Read: Anytime
Write: Anytime
Table 5-3. 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 the device overview chapter for availability and connectivity of
ETRIG3–0 inputs. If ETRIG3–0 input option is not available, writing a 1 to ETRISEL only sets the bit but has
not effect, that means still one of the AD channels (selected by ETRIGCH2–0) is the source for external trigger.
The coding is summarized in Table 5-4.
2–0
External Trigger Channel Select — These bits select one of the AD channels or one of the ETRIG3–0 inputs
ETRIGCH[2:0] as source for the external trigger. The coding is summarized in Table 5-4.
Table 5-4. External Trigger Channel Select Coding
1
ETRIGSEL
ETRIGCH2
ETRIGCH1
ETRIGCH0
External trigger source is
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
ETRIG01
1
0
0
1
ETRIG11
1
0
1
0
ETRIG21
1
0
1
1
ETRIG31
1
1
X
X
Reserved
Only if ETRIG3–0 input option is available (see device overview chapter), else ETRISEL is
ignored, that means external trigger source is still on one of the AD channels selected by
ETRIGCH2–0
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
167
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.3
ATD Control Register 2 (ATDCTL2)
This register controls power down, interrupt and external trigger. Writes to this register will abort current
conversion sequence but will not start a new sequence.
7
R
W
Reset
ADPU
0
6
5
4
3
2
1
AFFC
AWAI
ETRIGLE
ETRIGP
ETRIGE
ASCIE
0
0
0
0
0
0
0
ASCIF
0
= Unimplemented or Reserved
Figure 5-5. ATD Control Register 2 (ATDCTL2)
Read: Anytime
Write: Anytime
Table 5-5. ATDCTL2 Field Descriptions
Field
Description
7
ADPU
ATD Power Up — This bit provides on/off control over the ATD block allowing reduced MCU power
consumption. Because analog electronic is turned off when powered down, the ATD requires a recovery time
period after ADPU bit is enabled.
0 Power down ATD
1 Normal ATD functionality
6
AFFC
ATD Fast Flag Clear All
0 ATD flag clearing operates normally (read the status register ATDSTAT1 before reading the result register to
clear the associate CCF flag).
1 Changes all ATD conversion complete flags to a fast clear sequence. Any access to a result register will
cause the associate CCF flag to clear automatically.
5
AWAI
ATD Power Down in Wait Mode — When entering wait mode this bit provides on/off control over the ATD block
allowing reduced MCU power. Because analog electronic is turned off when powered down, the ATD requires
a recovery time period after exit from Wait mode.
0 ATD continues to run in Wait mode
1 Halt conversion and power down ATD during wait mode
After exiting wait mode with an interrupt conversion will resume. But due to the recovery time the result of
this conversion should be ignored.
4
ETRIGLE
External Trigger Level/Edge Control — This bit controls the sensitivity of the external trigger signal. See
Table 5-6 for details.
3
ETRIGP
External Trigger Polarity — This bit controls the polarity of the external trigger signal. See Table 5-6 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 5-4. 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 sample and ATD conversions
processes with external events.
0 Disable external trigger
1 Enable external trigger
Note: If using one of the AD channel as external trigger (ETRIGSEL = 0) the conversion results for this channel
have no meaning while external trigger mode is enabled.
MC9S12XDP512 Data Sheet, Rev. 2.21
168
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Table 5-5. ATDCTL2 Field Descriptions (continued)
Field
Description
1
ASCIE
ATD Sequence Complete Interrupt Enable
0 ATD Sequence Complete interrupt requests are disabled.
1 ATD Interrupt will be requested whenever ASCIF = 1 is set.
0
ASCIF
ATD Sequence Complete Interrupt Flag — If ASCIE = 1 the ASCIF flag equals the SCF flag (see
Section 5.3.2.7, “ATD Status Register 0 (ATDSTAT0)”), else ASCIF reads zero. Writes have no effect.
0 No ATD interrupt occurred
1 ATD sequence complete interrupt pending
Table 5-6. External Trigger Configurations
5.3.2.4
ETRIGLE
ETRIGP
External Trigger Sensitivity
0
0
Falling edge
0
1
Rising edge
1
0
Low level
1
1
High level
ATD Control Register 3 (ATDCTL3)
This register controls the conversion sequence length, FIFO for results registers and behavior in freeze
mode. Writes to this register will abort current conversion sequence but will not start a new sequence.
7
R
0
W
Reset
0
6
5
4
3
2
1
0
S8C
S4C
S2C
S1C
FIFO
FRZ1
FRZ0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 5-6. ATD Control Register 3 (ATDCTL3)
Read: Anytime
Write: Anytime
Table 5-7. ATDCTL3 Field Descriptions
Field
Description
6–3
S8C, S4C,
S2C, S1C
Conversion Sequence Length — These bits control the number of conversions per sequence. Table 5-8 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
169
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Table 5-7. ATDCTL3 Field Descriptions (continued)
Field
Description
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,
the second result in the second result register, 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 (CC2-0 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 by write to an ATDCTL register (ATDCTL5-0) 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).
Finally, 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.
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 5-9. 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.
Table 5-8. Conversion Sequence Length Coding
S8C
S4C
S2C
S1C
Number of Conversions
per Sequence
0
0
0
0
8
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
X
X
X
8
Table 5-9. ATD Behavior in Freeze Mode (Breakpoint)
FRZ1
FRZ0
Behavior in Freeze Mode
0
0
Continue conversion
0
1
Reserved
1
0
Finish current conversion, then freeze
1
1
Freeze Immediately
MC9S12XDP512 Data Sheet, Rev. 2.21
170
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.5
ATD Control Register 4 (ATDCTL4)
This register selects the conversion clock frequency, the length of the second phase of the sample time and
the resolution of the A/D conversion (i.e.: 8-bits or 10-bits). Writes to this register will abort current
conversion sequence but will not start a new sequence.
R
W
Reset
7
6
5
4
3
2
1
0
SRES8
SMP1
SMP0
PRS4
PRS3
PRS2
PRS1
PRS0
0
0
0
0
0
1
0
1
Figure 5-7. ATD Control Register 4 (ATDCTL4)
Read: Anytime
Write: Anytime
Table 5-10. ATDCTL4 Field Descriptions
Field
Description
7
SRES8
A/D Resolution Select — This bit selects the resolution of A/D conversion results as either 8 or 10 bits. The
A/D converter has an accuracy of 10 bits; however, if low resolution is required, the conversion can be speeded
up by selecting 8-bit resolution.
0 10-bit resolution
8-bit resolution
6–5
SMP[1:0]
Sample Time Select — These two bits select the length of the second phase 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). The sample time consists of two phases. The first phase is two ATD conversion clock
cycles long and transfers the sample quickly (via the buffer amplifier) onto the A/D machine’s storage node.
The second phase attaches the external analog signal directly to the storage node for final charging and high
accuracy. Table 5-11 lists the lengths available for the second sample phase.
4–0
PRS[4:0]
ATD Clock Prescaler — These 5 bits are the binary value prescaler value PRS. The ATD conversion clock
frequency is calculated as follows:
[ BusClock ]
ATDclock = --------------------------------- × 0.5
[ PRS + 1 ]
Note: The maximum ATD conversion clock frequency is half the bus clock. The default (after reset) prescaler
value is 5 which results in a default ATD conversion clock frequency that is bus clock divided by 12.
Table 5-12 illustrates the divide-by operation and the appropriate range of the bus clock.
Table 5-11. Sample Time Select
SMP1
SMP0
Length of 2nd Phase of Sample Time
0
0
2 A/D conversion clock periods
0
1
4 A/D conversion clock periods
1
0
8 A/D conversion clock periods
1
1
16 A/D conversion clock periods
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
171
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Table 5-12. Clock Prescaler Values
Prescale Value
Total Divisor
Value
Max. Bus Clock1
Min. Bus Clock2
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111
Divide by 2
Divide by 4
Divide by 6
Divide by 8
Divide by 10
Divide by 12
Divide by 14
Divide by 16
Divide by 18
Divide by 20
Divide by 22
Divide by 24
Divide by 26
Divide by 28
Divide by 30
Divide by 32
Divide by 34
Divide by 36
Divide by 38
Divide by 40
Divide by 42
Divide by 44
Divide by 46
Divide by 48
Divide by 50
Divide by 52
Divide by 54
Divide by 56
Divide by 58
Divide by 60
Divide by 62
Divide by 64
4 MHz
8 MHz
12 MHz
16 MHz
20 MHz
24 MHz
28 MHz
32 MHz
36 MHz
40 MHz
44 MHz
48 MHz
52 MHz
56 MHz
60 MHz
64 MHz
68 MHz
72 MHz
76 MHz
80 MHz
84 MHz
88 MHz
92 MHz
96 MHz
100 MHz
104 MHz
108 MHz
112 MHz
116 MHz
120 MHz
124 MHz
128 MHz
1 MHz
2 MHz
3 MHz
4 MHz
5 MHz
6 MHz
7 MHz
8 MHz
9 MHz
10 MHz
11 MHz
12 MHz
13 MHz
14 MHz
15 MHz
16 MHz
17 MHz
18 MHz
19 MHz
20 MHz
21 MHz
22 MHz
23 MHz
24 MHz
25 MHz
26 MHz
27 MHz
28 MHz
29 MHz
30 MHz
31 MHz
32 MHz
1
Maximum ATD conversion clock frequency is 2 MHz. The maximum allowed bus clock frequency is
shown in this column.
2 Minimum ATD conversion clock frequency is 500 kHz. The minimum allowed bus clock frequency is
shown in this column.
MC9S12XDP512 Data Sheet, Rev. 2.21
172
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.6
ATD Control Register 5 (ATDCTL5)
This register selects the type of conversion sequence and the analog input channels sampled. Writes to this
register will abort current conversion sequence and start a new conversion sequence.
7
R
W
Reset
6
DJM
0
5
4
DSGN
SCAN
MULT
0
0
0
3
0
0
2
1
0
CC
CB
CA
0
0
0
= Unimplemented or Reserved
Figure 5-8. ATD Control Register 5 (ATDCTL5)
Read: Anytime
Write: Anytime
Table 5-13. ATDCTL5 Field Descriptions
Field
Description
7
DJM
Result Register Data Justification — This bit controls justification of conversion data in the result registers.
See Section 5.3.2.13, “ATD Conversion Result Registers (ATDDRx),” for details.
0 Left justified data in the result registers
1 Right justified data in the result registers
6
DSGN
Result Register Data Signed or Unsigned Representation — This bit selects between signed and unsigned
conversion data representation in the result registers. Signed data is represented as 2’s complement. Signed
data is not available in right justification. See Section 5.3.2.13, “ATD Conversion Result Registers (ATDDRx),”
for details.
0 Unsigned data representation in the result registers
1 Signed data representation in the result registers
Table 5-14 summarizes the result data formats available and how they are set up using the control bits.
Table 5-15 illustrates the difference between the signed and unsigned, left justified output codes for an input
signal range between 0 and 5.12 Volts.
5
SCAN
Continuous Conversion Sequence Mode — This bit selects whether conversion sequences are performed
continuously or only once.
0 Single conversion sequence
1 Continuous conversion sequences (scan mode)
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 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 (CC, CB, CA control
bits); subsequent channels sampled in the sequence are determined by incrementing the channel selection
code.
0 Sample only one channel
1 Sample across several channels
2–0
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 5-16 lists the coding used to select the various analog input
channels. In the case of single channel scans (MULT = 0), this selection code specified the channel examined.
In the case of multi-channel scans (MULT = 1), this selection code represents the first channel to be examined
in the conversion sequence. Subsequent channels are determined by incrementing channel selection code;
selection codes that reach the maximum value wrap around to the minimum value.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
173
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
Table 5-14. Available Result Data Formats
SRES8
DJM
DSGN
Result Data Formats
Description and Bus Bit Mapping
1
1
1
0
0
0
0
0
1
0
0
1
0
1
X
0
1
X
8-bit / left justified / unsigned — bits 8–15
8-bit / left justified / signed — bits 8–15
8-bit / right justified / unsigned — bits 0–7
10-bit / left justified / unsigned — bits 6–15
10-bit / left justified / signed — bits 6–15
10-bit / right justified / unsigned — bits 0–9
Table 5-15. Left Justified, Signed, and Unsigned ATD Output Codes
Input Signal
VRL = 0 Volts
VRH = 5.12 Volts
Signed
8-Bit
Codes
Unsigned
8-Bit
Codes
Signed
10-Bit
Codes
Unsigned
10-Bit
Codes
5.120 Volts
5.100
5.080
7F
7F
7E
FF
FF
FE
7FC0
7F00
7E00
FFC0
FF00
FE00
2.580
2.560
2.540
01
00
FF
81
80
7F
0100
0000
FF00
8100
8000
7F00
0.020
0.000
81
80
01
00
8100
8000
0100
0000
Table 5-16. Analog Input Channel Select Coding
CC
CB
CA
Analog Input
Channel
0
0
0
AN0
0
0
1
AN1
0
1
0
AN2
0
1
1
AN3
1
0
0
AN4
1
0
1
AN5
1
1
0
AN6
1
1
1
AN7
MC9S12XDP512 Data Sheet, Rev. 2.21
174
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.7
ATD Status Register 0 (ATDSTAT0)
This read-only register contains the sequence complete flag, overrun flags for external trigger and FIFO
mode, and the conversion counter.
7
R
W
Reset
6
0
SCF
0
0
5
4
ETORF
FIFOR
0
0
3
2
1
0
0
CC2
CC1
CC0
0
0
0
0
= Unimplemented or Reserved
Figure 5-9. ATD Status Register 0 (ATDSTAT0)
Read: Anytime
Write: Anytime (No effect on (CC2, CC1, CC0))
Table 5-17. ATDSTAT0 Field Descriptions
Field
7
SCF
Description
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 ATDCTL2, ATDCTL3 or ATDCTL4 (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
FIFO 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) Start a new conversion sequence (write to ATDCTL5 or external trigger)
0 No over run has occurred
1 An over run condition exists
2–0
CC[2:0]
Conversion Counter — These 3 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. 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 by write to an ATDCTL register (ATDCTL5-0) clears the
conversion counter even if FIFO=1.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
175
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.8
R
Reserved Register (ATDTEST0)
7
6
5
4
3
2
1
0
U
U
U
U
U
U
U
U
1
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 5-10. Reserved Register (ATDTEST0)
Read: Anytime, returns unpredictable values
Write: Anytime in special modes, unimplemented in normal modes
NOTE
Writing to this register when in special modes can alter functionality.
5.3.2.9
ATD Test Register 1 (ATDTEST1)
This register contains the SC bit used to enable special channel conversions.
R
7
6
5
4
3
2
1
U
U
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
SC
0
= Unimplemented or Reserved
Figure 5-11. ATD Test Register 1 (ATDTEST1)
Read: Anytime, returns unpredictable values for Bit7 and Bit6
Write: Anytime
Table 5-18. ATDTEST1 Field Descriptions
Field
Description
0
SC
Special Channel Conversion Bit — If this bit is set, then special channel conversion can be selected using CC,
CB and CA of ATDCTL5. Table 5-19 lists the coding.
0 Special channel conversions disabled
1 Special channel conversions enabled
Note: Always write remaining bits of ATDTEST1 (Bit7 to Bit1) zero when writing SC bit. Not doing so might result
in unpredictable ATD behavior.
Table 5-19. Special Channel Select Coding
SC
CC
CB
CA
Analog Input Channel
1
0
X
X
Reserved
1
1
0
0
VRH
1
1
0
1
VRL
1
1
1
0
(VRH+VRL) / 2
1
1
1
1
Reserved
MC9S12XDP512 Data Sheet, Rev. 2.21
176
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.10
ATD Status Register 1 (ATDSTAT1)
This read-only register contains the conversion complete flags.
R
7
6
5
4
3
2
1
0
CCF7
CCF6
CCF5
CCF4
CCF3
CCF2
CCF1
CCF0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 5-12. ATD Status Register 1 (ATDSTAT1)
Read: Anytime
Write: Anytime, no effect
Table 5-20. ATDSTAT1 Field Descriptions
Field
Description
7–0
CCF[7:0]
Conversion Complete Flag x (x = 7, 6, 5, 4, 3, 2, 1, 0) — A conversion complete flag is set at the end of each
conversion in a conversion sequence. The flags are associated with the conversion position in a sequence (and
also the result register number). Therefore, CCF0 is set when the first conversion in a sequence is complete and
the result is available in result register ATDDR0; CCF1 is set when the second conversion in a sequence is
complete and the result is available in ATDDR1, and so forth. A flag CCFx (x = 7, 6, 5, 4, 3, 2,1, 70) is cleared
when one of the following occurs:
A) Write to ATDCTL5 (a new conversion sequence is started)
B) If AFFC=0 and read of ATDSTAT1 followed by read of result register ATDDRx
C) If AFFC=1 and read of result register ATDDRx
In case of a concurrent set and clear on CCFx: The clearing by method A) will overwrite the set. The clearing by
methods B) or C) will be overwritten by the set.
0 Conversion number x not completed
1 Conversion number x has completed, result ready in ATDDRx
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
177
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.11
R
W
Reset
ATD Input Enable Register (ATDDIEN)
7
6
5
4
3
2
1
0
IEN7
IEN6
IEN5
IEN4
IEN3
IEN2
IEN1
IEN0
0
0
0
0
0
0
0
0
Figure 5-13. ATD Input Enable Register (ATDDIEN)
Read: Anytime
Write: Anytime
Table 5-21. ATDDIEN Field Descriptions
Field
Description
7–0
IEN[7:0]
ATD Digital Input Enable on channel x (x = 7, 6, 5, 4, 3, 2, 1, 0) — This bit controls the digital input buffer from
the analog input pin (ANx) to PTADx data register.
0 Disable digital input buffer to PTADx
1 Enable digital input buffer to PTADx.
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.
5.3.2.12
Port Data Register (PORTAD)
The data port associated with the ATD can be configured as general-purpose I/O or input only, as specified
in the device overview. The port pins are shared with the analog A/D inputs AN7–0.
R
7
6
5
4
3
2
1
0
PTAD7
PTAD6
PTAD5
PTAD4
PTAD3
PTAD2
PTAD1
PTAD0
1
1
1
1
1
1
1
1
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
W
Reset
Pin
Function
= Unimplemented or Reserved
Figure 5-14. Port Data Register (PORTAD)
Read: Anytime
Write: Anytime, no effect
The A/D input channels may be used for general purpose digital input.
Table 5-22. PORTAD Field Descriptions
Field
Description
7–0
PTAD[7:0]
A/D Channel x (ANx) Digital Input (x = 7, 6, 5, 4, 3, 2, 1, 0) — If the digital input buffer on the ANx pin is enabled
(IENx = 1) or channel x is enabled as external trigger (ETRIGE = 1,ETRIGCH[2–0] = x,ETRIGSEL = 0) read
returns the logic level on ANx pin (signal potentials not meeting VIL or VIH specifications will have an
indeterminate value).
If the digital input buffers are disabled (IENx = 0) and channel x is not enabled as external trigger, read returns
a “1”.
Reset sets all PORTAD0 bits to “1”.
MC9S12XDP512 Data Sheet, Rev. 2.21
178
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.3.2.13
ATD Conversion Result Registers (ATDDRx)
The A/D conversion results are stored in 8 read-only result registers. The result data is formatted in the
result registers based on two criteria. First there is left and right justification; this selection is made using
the DJM control bit in ATDCTL5. Second there is signed and unsigned data; this selection is made using
the DSGN control bit in ATDCTL5. Signed data is stored in 2’s complement format and only exists in left
justified format. Signed data selected for right justified format is ignored.
Read: Anytime
Write: Anytime in special mode, unimplemented in normal modes
5.3.2.13.1
Left Justified Result Data
7
R BIT 9 MSB
R BIT 7 MSB
6
5
4
3
2
1
0
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
0
0
0
0
0
0
0
10-bit data
8-bit data
W
Reset
0
= Unimplemented or Reserved
Figure 5-15. Left Justified, ATD Conversion Result Register, High Byte (ATDDRxH)
R
R
7
6
5
4
3
2
1
0
BIT 1
U
BIT 0
U
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 5-16. Left Justified, ATD Conversion Result Register, Low Byte (ATDDRxL)
5.3.2.13.2
R
R
Right Justified Result Data
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
0
0
0
0
0
0
0
0
10-bit data
8-bit data
W
Reset
= Unimplemented or Reserved
Figure 5-17. Right Justified, ATD Conversion Result Register, High Byte (ATDDRxH)
7
R
BIT 7
R BIT 7 MSB
6
5
4
3
2
1
0
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
0
0
0
0
0
0
0
10-bit data
8-bit data
W
Reset
0
= Unimplemented or Reserved
Figure 5-18. Right Justified, ATD Conversion Result Register, Low Byte (ATDDRxL)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
179
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.4
Functional Description
The ATD is structured in an analog and a digital sub-block.
5.4.1
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.
5.4.1.1
Sample and Hold Machine
The sample and hold (S/H) machine accepts analog signals from the external surroundings and stores them
as capacitor charge on a storage node.
The sample process uses a two stage approach. During the first stage, the sample amplifier is used to
quickly charge the storage node.The second stage connects the input directly to the storage node to
complete the sample for high accuracy.
When not sampling, the sample and hold machine disables its own clocks. The analog electronics still draw
their quiescent current. The power down (ADPU) bit must be set to disable both the digital clocks and the
analog power consumption.
The input analog signals are unipolar and must fall within the potential range of VSSA to VDDA.
5.4.1.2
Analog Input Multiplexer
The analog input multiplexer connects one of the 8 external analog input channels to the sample and hold
machine.
5.4.1.3
Sample Buffer Amplifier
The sample amplifier is used to buffer the input analog signal so that the storage node can be quickly
charged to the sample potential.
5.4.1.4
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 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 disables its own clocks. The analog electronics still draws quiescent
current. The power down (ADPU) bit must be set to disable both the digital clocks and the analog power
consumption.
Only analog input signals within the potential range of VRL to VRH (A/D reference potentials) will result
in a non-railed digital output codes.
MC9S12XDP512 Data Sheet, Rev. 2.21
180
Freescale Semiconductor
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.4.2
Digital Sub-Block
This subsection explains some of the digital features in more detail. See register descriptions for all details.
5.4.2.1
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 7, configurable in ATDCTL1) is programmable to
be edge or level sensitive with polarity control. Table 5-23 gives a brief description of the different
combinations of control bits and their effect on the external trigger function.
Table 5-23. 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. In both
cases, the maximum latency time is one bus clock cycle plus any skew or delay introduced by the trigger
circuitry.
NOTE
The conversion results for the external trigger ATD channel 7 have no
meaning while external trigger mode is enabled.
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
181
Chapter 5 Analog-to-Digital Converter (S12ATD10B8CV2)
5.4.2.2
General Purpose Digital Input Port Operation
The input channel pins can be multiplexed between analog and digital data. As analog inputs, they are
multiplexed and sampled to supply signals to the A/D converter. As digital inputs, they supply external
input data that can be accessed through the digital port register PORTAD (input-only).
The analog/digital multiplex operation is performed in the input pads. The input pad is always connected
to the analog inputs of the ATD. 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.
5.4.2.3
Low Power Modes
The ATD can be configured for lower MCU power consumption in 3 different ways:
1. Stop mode: This halts A/D conversion. Exit from stop mode will resume A/D conversion, but due
to the recovery time the result of this conversion should be ignored.
2. Wait mode with AWAI = 1: This halts A/D conversion. Exit from wait mode will resume A/D
conversion, but due to the recovery time the result of this conversion should be ignored.
3. Writing ADPU = 0 (Note that all ATD registers remain accessible.): This aborts any A/D
conversion in progress.
Note that the reset value for the ADPU bit is zero. Therefore, when this module is reset, it is reset into the
power down state.
5.5
Resets
At reset the ATD is in a power down state. The reset state of each individual bit is listed within the Register
Description section (see Section 5.3, “Memory Map and Register Definition”), which details the registers
and their bit-field.
5.6
Interrupts
The interrupt requested by the ATD is listed in Table 5-24. Refer to the device overview chapter for related
vector address and priority.
Table 5-24. ATD Interrupt Vectors
Interrupt Source
Sequence complete
interrupt
CCR
Mask
Local Enable
I bit
ASCIE in ATDCTL2
See register descriptions for further details.
MC9S12XDP512 Data Sheet, Rev. 2.21
182
Freescale Semiconductor
Chapter 6
XGATE (S12XGATEV2)
6.1
Introduction
The XGATE module is a peripheral co-processor that allows autonomous data transfers between the
MCU’s peripherals and the internal memories. It has a built in RISC core that is able to pre-process the
transferred data and perform complex communication protocols.
The XGATE module is intended to increase the MCU’s data throughput by lowering the S12X_CPU’s
interrupt load.
Figure 6-1 gives an overview on the XGATE architecture.
This document describes the functionality of the XGATE module, including:
• XGATE registers (Section 6.3, “Memory Map and Register Definition”)
• XGATE RISC core (Section 6.4.1, “XGATE RISC Core”)
• Hardware semaphores (Section 6.4.4, “Semaphores”)
• Interrupt handling (Section 6.5, “Interrupts”)
• Debug features (Section 6.6, “Debug Mode”)
• Security (Section 6.7, “Security”)
• Instruction set (Section 6.8, “Instruction Set”)
6.1.1
Glossary of Terms
XGATE Request
A service request from a peripheral module which is directed to the XGATE by the S12X_INT
module (see Figure 6-1).
XGATE Channel
The resources in the XGATE module (i.e. Channel ID number, Priority level, Service Request
Vector, Interrupt Flag) which are associated with a particular XGATE Request.
XGATE Channel ID
A 7-bit identifier associated with an XGATE channel. In S12X designs valid Channel IDs range
from $78 to $09.
XGATE Channel Interrupt
An S12X_CPU interrupt that is triggered by a code sequence running on the XGATE module.
XGATE Software Channel
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
183
Chapter 6 XGATE (S12XGATEV2)
Special XGATE channel that is not associated with any peripheral service request. A Software
Channel is triggered by its Software Trigger Bit which is implemented in the XGATE module.
XGATE Semaphore
A set of hardware flip-flops that can be exclusively set by either the S12X_CPU or the XGATE.
(see 6.4.4/6-204)
XGATE Thread
A code sequence which is executed by the XGATE’s RISC core after receiving an XGATE request.
XGATE Debug Mode
A special mode in which the XGATE’s RISC core is halted for debug purposes. This mode enables
the XGATE’s debug features (see 6.6/6-206).
XGATE Software Error
The XGATE is able to detect a number of error conditions caused by erratic software (see
6.4.5/6-205). These error conditions will cause the XGATE to seize program execution and flag an
Interrupt to the S12X_CPU.
Word
A 16 bit entity.
Byte
An 8 bit entity.
6.1.2
Features
The XGATE module includes these features:
• Data movement between various targets (i.e Flash, RAM, and peripheral modules)
• Data manipulation through built in RISC core
• Provides up to 112 XGATE channels
— 104 hardware triggered channels
— 8 software triggered channels
• Hardware semaphores which are shared between the S12X_CPU and the XGATE module
• Able to trigger S12X_CPU interrupts upon completion of an XGATE transfer
• Software error detection to catch erratic application code
6.1.3
Modes of Operation
There are four run modes on S12X devices.
• Run mode, wait mode, stop mode
The XGATE is able to operate in all of these three system modes. Clock activity will be
automatically stopped when the XGATE module is idle.
• Freeze mode (BDM active)
MC9S12XDP512 Data Sheet, Rev. 2.21
184
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
In freeze mode all clocks of the XGATE module may be stopped, depending on the module
configuration (see Section 6.3.1.1, “XGATE Control Register (XGMCTL)”).
6.1.4
Block Diagram
Figure Figure 6-1 shows a block diagram of the XGATE.
Peripheral Interrupts
XGATE
REQUESTS
XGATE
XGATE
INTERRUPTS
S12X_INT
Interrupt Flags
Semaphores
RISC Core
Software
Triggers
Data/Code
Software Triggers
S12X_DBG
S12X_MMC
Peripherals
Figure 6-1. XGATE Block Diagram
6.2
External Signal Description
The XGATE module has no external pins.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
185
Chapter 6 XGATE (S12XGATEV2)
6.3
Memory Map and Register Definition
This section provides a detailed description of address space and registers used by the XGATE module.
The memory map for the XGATE module is given below in Figure 6-2.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. Reserved registers read zero. Write accesses to the reserved
registers have no effect.
6.3.1
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
XGMCTL
R
W
15
14
13
12
11
10
9
8
0
0
0
0
0
0
0
0
XGEM
XG
XG
XG
XGSSM
FRZM DBGM
FACTM
XGMCHID R
XG
SWEIFM
XGIEM
7
6
5
4
XGE XGFRZ XGDBG XGSS
0
3
XG
FACT
2
0
1
0
XG
XGIE
SWEIF
XGCHID[6:0]
W
Reserved
R
W
Reserved
R
W
Reserved
R
W
XGVBR
R
XGVBR[15:1]
W
0
= Unimplemented or Reserved
Figure 6-2. XGATE Register Summary (Sheet 1 of 3)
MC9S12XDP512 Data Sheet, Rev. 2.21
186
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
XGIF
R
127
126
125
124
123
122
121
0
0
0
0
0
0
0
111
Register
Name
113
112
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
XGIF_4F XGIF_4E XGIF_4D XGIF_4C XGIF_4B XGIF_4A XGIF_49 XGIF_48 XGF _47 XGIF_46 XGIF_45 XGIF_44 XGIF_43 XGIF_42 XGIF_41 XGIF_40
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
R
W
XGIF_3F XGIF_3E XGIF_3D XGIF_3C XGIF_3B XGIF_3A XGIF_39 XGIF_38 XGF _37 XGIF_36 XGIF_35 XGIF_34 XGIF_33 XGIF_32 XGIF_31 XGIF_30
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
R
W
XGIF_2F XGIF_2E XGIF_2D XGIF_2C XGIF_2B XGIF_2A XGIF_29 XGIF_28 XGF _27 XGIF_26 XGIF_25 XGIF_24 XGIF_23 XGIF_22 XGIF_21 XGIF_20
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R
W
XGIF_1F XGIF_1E XGIF_1D XGIF_1C XGIF_1B XGIF_1A XGIF_19 XGIF_18 XGF _17 XGIF_16 XGIF_15 XGIF_14 XGIF_13 XGIF_12 XGIF_11 XGIF_10
15
XGIF
114
R
W
XGIF
115
XGIF_5F XGIF_5E XGIF_5D XGIF_5C XGIF_5B XGIF_5A XGIF_59 XGIF_58 XGF_57 XGIF_56 XGIF_55 XGIF_54 XGIF_53 XGIF_52 XGIF_51 XGIF_50
79
XGIF
116
R
W
XGIF
117
XGIF_6F XGIF_6E XGIF_6D XGIF_6C XGIF_6B XGIF_6A XGIF_69 XGIF_68 XGF_67 XGIF_66 XGIF_65 XGIF_64 XGIF_63 XGIF_62 XGIF_61 XGIF_60
95
XGIF
118
R
W
XGIF
119
XGIF_78 XGF_77 XGIF_76 XGIF_75 XGIF_74 XGIF_73 XGIF_72 XGIF_71 XGIF_70
W
XGIF
120
14
13
12
11
10
9
R
W
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
XGIF_0F XGIF_0E XGIF_0D XGIF_0C XGIF_0B XGIF_0A XGIF_09
= Unimplemented or Reserved
Figure 6-2. XGATE Register Summary (Sheet 2 of 3)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
187
Chapter 6 XGATE (S12XGATEV2)
XGSWTM R
15
14
13
0
0
0
W
XGSEMM
R
W
Reserved
12
11
10
9
8
0
0
0
0
0
0
0
0
7
6
5
0
0
0
0
3
2
1
0
XGSWT[7:0]
XGSWTM[7:0]
0
4
XGSEM[7:0]
XGSEMM[7:0]
R
W
XGCCR
R
0
0
0
W
XGPC
R
XGN XGZ
XGV XGC
XGPC
W
Reserved
0
R
W
Reserved
R
W
XGR1
R
XGR1
W
XGR2
R
XGR2
W
XGR3
R
XGR3
W
XGR4
R
XGR4
W
XGR5
R
XGR5
W
XGR6
R
XGR6
W
XGR7
R
XGR7
W
= Unimplemented or Reserved
Figure 6-2. XGATE Register Summary (Sheet 3 of 3)
MC9S12XDP512 Data Sheet, Rev. 2.21
188
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.3.1.1
XGATE Control Register (XGMCTL)
All module level switches and flags are located in the module control register Figure 6-3.
15
14
13
12
11
10
9
8
0
0
0
0
0
0
0
0
XG
SSM
XG
FACTM
0
0
R
W
XGEM
Reset
0
XG
XG
FRZM DBGM
0
0
7
0
0
5
4
3
2
0
XG
XGIEM
SWEIFM
0
6
XGE
XGFRZ XGDBG XGSS XGFACT
0
0
0
0
0
0
1
0
XG
SWEIF
XGIE
0
0
= Unimplemented or Reserved
Figure 6-3. XGATE Control Register (XGMCTL)
Read: Anytime
Write: Anytime
Table 6-1. XGMCTL Field Descriptions (Sheet 1 of 3)
Field
Description
15
XGEM
XGE Mask — This bit controls the write access to the XGE bit. The XGE bit can only be set or cleared if a "1" is
written to the XGEM bit in the same register access.
Read:
This bit will always read "0".
Write:
0 Disable write access to the XGE in the same bus cycle
1 Enable write access to the XGE in the same bus cycle
14
XGFRZM
XGFRZ Mask — This bit controls the write access to the XGFRZ bit. The XGFRZ bit can only be set or cleared
if a "1" is written to the XGFRZM bit in the same register access.
Read:
This bit will always read "0".
Write:
0 Disable write access to the XGFRZ in the same bus cycle
1 Enable write access to the XGFRZ in the same bus cycle
13
XGDBGM
XGDBG Mask — This bit controls the write access to the XGDBG bit. The XGDBG bit can only be set or cleared
if a "1" is written to the XGDBGM bit in the same register access.
Read:
This bit will always read "0".
Write:
0 Disable write access to the XGDBG in the same bus cycle
1 Enable write access to the XGDBG in the same bus cycle
12
XGSSM
XGSS Mask — This bit controls the write access to the XGSS bit. The XGSS bit can only be set or cleared if a
"1" is written to the XGSSM bit in the same register access.
Read:
This bit will always read "0".
Write:
0 Disable write access to the XGSS in the same bus cycle
1 Enable write access to the XGSS in the same bus cycle
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
189
Chapter 6 XGATE (S12XGATEV2)
Table 6-1. XGMCTL Field Descriptions (Sheet 2 of 3)
Field
11
XGFACTM
Description
XGFACT Mask — This bit controls the write access to the XGFACT bit. The XGFACT bit can only be set or
cleared if a "1" is written to the XGFACTM bit in the same register access.
Read:
This bit will always read "0".
Write:
0 Disable write access to the XGFACT in the same bus cycle
1 Enable write access to the XGFACT in the same bus cycle
XGSWEIF Mask — This bit controls the write access to the XGSWEIF bit. The XGSWEIF bit can only be cleared
9
XGSWEIFM if a "1" is written to the XGSWEIFM bit in the same register access.
Read:
This bit will always read "0".
Write:
0 Disable write access to the XGSWEIF in the same bus cycle
1 Enable write access to the XGSWEIF in the same bus cycle
8
XGIEM
XGIE Mask — This bit controls the write access to the XGIE bit. The XGIE bit can only be set or cleared if a "1"
is written to the XGIEM bit in the same register access.
Read:
This bit will always read "0".
Write:
0 Disable write access to the XGIE in the same bus cycle
1 Enable write access to the XGIE in the same bus cycle
7
XGE
XGATE Module Enable — This bit enables the XGATE module. If the XGATE module is disabled, pending
XGATE requests will be ignored. The thread that is executed by the RISC core while the XGE bit is cleared will
continue to run.
Read:
0 XGATE module is disabled
1 XGATE module is enabled
Write:
0 Disable XGATE module
1 Enable XGATE module
6
XGFRZ
Halt XGATE in Freeze Mode — The XGFRZ bit controls the XGATE operation in Freeze Mode (BDM active).
Read:
0 RISC core operates normally in Freeze (BDM active)
1 RISC core stops in Freeze Mode (BDM active)
Write:
0 Don’t stop RISC core in Freeze Mode (BDM active)
1 Stop RISC core in Freeze Mode (BDM active)
5
XGDBG
XGATE Debug Mode — This bit indicates that the XGATE is in Debug Mode (see Section 6.6, “Debug Mode”).
Debug Mode can be entered by Software Breakpoints (BRK instruction), Tagged or Forced Breakpoints (see
S12X_DBG Section), or by writing a "1" to this bit.
Read:
0 RISC core is not in Debug Mode
1 RISC core is in Debug Mode
Write:
0 Leave Debug Mode
1 Enter Debug Mode
Note: Freeze Mode and Software Error Interrupts have no effect on the XGDBG bit.
MC9S12XDP512 Data Sheet, Rev. 2.21
190
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
Table 6-1. XGMCTL Field Descriptions (Sheet 3 of 3)
Field
Description
4
XGSS
XGATE Single Step — This bit forces the execution of a single instruction if the XGATE is in DEBUG Mode and
no software error has occurred (XGSWEIF cleared).
Read:
0 No single step in progress
1 Single step in progress
Write
0 No effect
1 Execute a single RISC instruction
Note: Invoking a Single Step will cause the XGATE to temporarily leave Debug Mode until the instruction has
been executed.
3
XGFACT
Fake XGATE Activity — This bit forces the XGATE to flag activity to the MCU even when it is idle. When it is set
the MCU will never enter system stop mode which assures that peripheral modules will be clocked during XGATE
idle periods
Read:
0 XGATE will only flag activity if it is not idle or in debug mode.
1 XGATE will always signal activity to the MCU.
Write:
0 Only flag activity if not idle or in debug mode.
1 Always signal XGATE activity.
1
XGSWEIF
XGATE Software Error Interrupt Flag — This bit signals a pending Software Error Interrupt. It is set if the RISC
core detects an error condition (see Section 6.4.5, “Software Error Detection”). The RISC core is stopped while
this bit is set. Clearing this bit will terminate the current thread and cause the XGATE to become idle.
Read:
0 Software Error Interrupt is not pending
1 Software Error Interrupt is pending if XGIE is set
Write:
0 No effect
1 Clears the XGSWEIF bit
0
XGIE
XGATE Interrupt Enable — This bit acts as a global interrupt enable for the XGATE module
Read:
0 All XGATE interrupts disabled
1 All XGATE interrupts enabled
Write:
0 Disable all XGATE interrupts
1 Enable all XGATE interrupts
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
191
Chapter 6 XGATE (S12XGATEV2)
6.3.1.2
XGATE Channel ID Register (XGCHID)
The XGATE channel ID register (Figure 6-4) shows the identifier of the XGATE channel that is currently
active. This register will read “$00” if the XGATE module is idle. In debug mode this register can be used
to start and terminate threads (see Section 6.6.1, “Debug Features”).
7
R
6
5
4
3
0
2
1
0
0
0
0
XGCHID[6:0]
W
Reset
0
0
0
0
0
= Unimplemented or Reserved
Figure 6-4. XGATE Channel ID Register (XGCHID)
Read: Anytime
Write: In Debug Mode
Table 6-2. XGCHID Field Descriptions
Field
Description
6–0
Request Identifier — ID of the currently active channel
XGCHID[6:0]
6.3.1.3
XGATE Vector Base Address Register (XGVBR)
The vector base address register (Figure 6-5 and Figure 6-6) determines the location of the XGATE vector
block.
15
14
13
12
11
10
9
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
XGVBR[15:1]
W
Reset
8
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 6-5. XGATE Vector Base Address Register (XGVBR)
Read: Anytime
Write: Only if the module is disabled (XGE = 0) and idle (XGCHID = $00))
Table 6-3. XGVBR Field Descriptions
Field
Description
15–1
Vector Base Address — The XGVBR register holds the start address of the vector block in the XGATE
XBVBR[15:1] memory map.
MC9S12XDP512 Data Sheet, Rev. 2.21
192
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.3.1.4
XGATE Channel Interrupt Flag Vector (XGIF)
The interrupt flag vector (Figure 6-6) provides access to the interrupt flags bits of each channel. Each flag
may be cleared by writing a "1" to its bit location.
R
127
126
125
124
123
122
121
0
0
0
0
0
0
0
120
119
XGIF_78
XGF_77
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
W
Reset
R
W
Reset
R
W
Reset
R
W
Reset
R
W
Reset
R
W
Reset
R
W
Reset
R
W
Reset
XGIF_6F XGIF_6E XGIF_6D XGIF_6C XGIF_6B XGIF_6A XGIF_69 XGIF_68
XGF_67
118
117
116
115
114
113
112
XGIF_76 XGIF_75 XGIF_74 XGIF_73 XGIF_72 XGIF_71 XGIF_70
XGIF_66 XGIF_65 XGIF_64 XGIF_63 XGIF_62 XGIF_61 XGIF_60
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
XGIF_5F XGIF_5E XGIF_5D XGIF_5C XGIF_5B XGIF_5A XGIF_59 XGIF_58
XGF_57
XGIF_56 XGIF_55 XGIF_54 XGIF_53 XGIF_52 XGIF_51 XGIF_50
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
XGIF_4F XGIF_4E XGIF_4D XGIF_4C XGIF_4B XGIF_4A XGIF_49 XGIF_48 XGF _47 XGIF_46 XGIF_45 XGIF_44 XGIF_43 XGIF_42 XGIF_41 XGIF_40
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
XGIF_3F XGIF_3E XGIF_3D XGIF_3C XGIF_3B XGIF_3A XGIF_39 XGIF_38 XGF _37 XGIF_36 XGIF_35 XGIF_34 XGIF_33 XGIF_32 XGIF_31 XGIF_30
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
XGIF_2F XGIF_2E XGIF_2D XGIF_2C XGIF_2B XGIF_2A XGIF_29 XGIF_28 XGF _27 XGIF_26 XGIF_25 XGIF_24 XGIF_23 XGIF_22 XGIF_21 XGIF_20
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
XGIF_1F XGIF_1E XGIF_1D XGIF_1C XGIF_1B XGIF_1A XGIF_19 XGIF_18 XGF _17 XGIF_16 XGIF_15 XGIF_14 XGIF_13 XGIF_12 XGIF_11 XGIF_10
0
0
0
0
0
0
0
15
14
13
12
11
10
9
XGIF_0F XGIF_0E XGIF_0D XGIF_0C XGIF_0B XGIF_0A XGIF_09
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 6-6. XGATE Channel Interrupt Flag Vector (XGIF)
Read: Anytime
Write: Anytime
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
193
Chapter 6 XGATE (S12XGATEV2)
Table 6-4. XGIV Field Descriptions
Field
Description
127–9
XGIF[78:9]
Channel Interrupt Flags — These bits signal pending channel interrupts. They can only be set by the RISC
core. Each flag can be cleared by writing a "1" to its bit location. Unimplemented interrupt flags will always read
"0". Refer to Section “Interrupts” of the SoC Guide for a list of implemented Interrupts.
Read:
0 Channel interrupt is not pending
1 Channel interrupt is pending if XGIE is set
Write:
0 No effect
1 Clears the interrupt flag
NOTE
Suggested Mnemonics for accessing the interrupt flag vector on a word
basis are:
XGIF_7F_70 (XGIF[127:112]),
XGIF_6F_60 (XGIF[111:96]),
XGIF_5F_50 (XGIF[95:80]),
XGIF_4F_40 (XGIF[79:64]),
XGIF_3F_30 (XGIF[63:48]),
XGIF_2F_20 (XGIF[47:32]),
XGIF_1F_10 (XGIF[31:16]),
XGIF_0F_00 (XGIF[15:0])
MC9S12XDP512 Data Sheet, Rev. 2.21
194
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.3.1.5
XGATE Software Trigger Register (XGSWT)
The eight software triggers of the XGATE module can be set and cleared through the XGATE software
trigger register (Figure 6-7). The upper byte of this register, the software trigger mask, controls the write
access to the lower byte, the software trigger bits. These bits can be set or cleared if a "1" is written to the
associated mask in the same bus cycle.
R
15
14
13
12
11
10
9
8
0
0
0
0
0
0
0
0
0
0
0
6
5
0
0
0
0
0
4
3
2
1
0
0
0
0
XGSWT[7:0]
XGSWTM[7:0]
W
Reset
7
0
0
0
0
0
Figure 6-7. XGATE Software Trigger Register (XGSWT)
Read: Anytime
Write: Anytime
Table 6-5. XGSWT Field Descriptions
Field
Description
15–8
Software Trigger Mask — These bits control the write access to the XGSWT bits. Each XGSWT bit can only
XGSWTM[7:0] be written if a "1" is written to the corresponding XGSWTM bit in the same access.
Read:
These bits will always read "0".
Write:
0 Disable write access to the XGSWT in the same bus cycle
1 Enable write access to the corresponding XGSWT bit in the same bus cycle
7–0
XGSWT[7:0]
Software Trigger Bits — These bits act as interrupt flags that are able to trigger XGATE software channels.
They can only be set and cleared by software.
Read:
0 No software trigger pending
1 Software trigger pending if the XGIE bit is set
Write:
0 Clear Software Trigger
1 Set Software Trigger
NOTE
The XGATE channel IDs that are associated with the eight software triggers
are determined on chip integration level. (see Section “Interrupts” of the Soc
Guide)
XGATE software triggers work like any peripheral interrupt. They can be
used as XGATE requests as well as S12X_CPU interrupts. The target of the
software trigger must be selected in the S12X_INT module.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
195
Chapter 6 XGATE (S12XGATEV2)
6.3.1.6
XGATE Semaphore Register (XGSEM)
The XGATE provides a set of eight hardware semaphores that can be shared between the S12X_CPU and
the XGATE RISC core. Each semaphore can either be unlocked, locked by the S12X_CPU or locked by
the RISC core. The RISC core is able to lock and unlock a semaphore through its SSEM and CSEM
instructions. The S12X_CPU has access to the semaphores through the XGATE semaphore register
(Figure 6-8). Refer to section Section 6.4.4, “Semaphores” for details.
R
15
14
13
12
11
10
9
8
0
0
0
0
0
0
0
0
0
0
0
W
Reset
7
6
5
0
0
0
0
3
2
1
0
0
0
0
XGSEM[7:0]
XGSEMM[7:0]
0
4
0
0
0
0
0
Figure 6-8. XGATE Semaphore Register (XGSEM)
Read: Anytime
Write: Anytime (see Section 6.4.4, “Semaphores”)
Table 6-6. XGSEM Field Descriptions
Field
Description
15–8
Semaphore Mask — These bits control the write access to the XGSEM bits.
XGSEMM[7:0] Read:
These bits will always read "0".
Write:
0 Disable write access to the XGSEM in the same bus cycle
1 Enable write access to the XGSEM in the same bus cycle
7–0
XGSEM[7:0]
Semaphore Bits — These bits indicate whether a semaphore is locked by the S12X_CPU. A semaphore can
be attempted to be set by writing a "1" to the XGSEM bit and to the corresponding XGSEMM bit in the same
write access. Only unlocked semaphores can be set. A semaphore can be cleared by writing a "0" to the
XGSEM bit and a "1" to the corresponding XGSEMM bit in the same write access.
Read:
0 Semaphore is unlocked or locked by the RISC core
1 Semaphore is locked by the S12X_CPU
Write:
0 Clear semaphore if it was locked by the S12X_CPU
1 Attempt to lock semaphore by the S12X_CPU
MC9S12XDP512 Data Sheet, Rev. 2.21
196
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.3.1.7
XGATE Condition Code Register (XGCCR)
The XGCCR register (Figure 6-9) provides access to the RISC core’s condition code register.
R
7
6
5
4
0
0
0
0
0
0
0
0
W
Reset
3
2
1
0
XGN
XGZ
XGV
XGC
0
0
0
0
= Unimplemented or Reserved
Figure 6-9. XGATE Condition Code Register (XGCCR)
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-7. XGCCR Field Descriptions
Field
Description
3
XGN
Sign Flag — The RISC core’s Sign flag
2
XGZ
Zero Flag — The RISC core’s Zero flag
1
XGV
Overflow Flag — The RISC core’s Overflow flag
0
XGC
Carry Flag — The RISC core’s Carry flag
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
197
Chapter 6 XGATE (S12XGATEV2)
6.3.1.8
XGATE Program Counter Register (XGPC)
The XGPC register (Figure 6-10) provides access to the RISC core’s program counter.
15
14
13
12
11
10
9
8
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
XGPC
W
Reset
0
0
0
0
0
0
0
0
Figure 6-10. XGATE Program Counter Register (XGPC)
Figure 6-11.
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-8. XGPC Field Descriptions
Field
15–0
XGPC[15:0]
6.3.1.9
Description
Program Counter — The RISC core’s program counter
XGATE Register 1 (XGR1)
The XGR1 register (Figure 6-12) provides access to the RISC core’s register 1.
15
14
13
12
11
10
9
8
R
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
XGR1
W
Reset
7
0
0
0
0
0
0
0
0
Figure 6-12. XGATE Register 1 (XGR1)
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-9. XGR1 Field Descriptions
Field
15–0
XGR1[15:0]
Description
XGATE Register 1 — The RISC core’s register 1
MC9S12XDP512 Data Sheet, Rev. 2.21
198
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.3.1.10
XGATE Register 2 (XGR2)
The XGR2 register (Figure 6-13) provides access to the RISC core’s register 2.
15
14
13
12
11
10
9
8
R
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
XGR2
W
Reset
7
0
0
0
0
0
0
0
0
Figure 6-13. XGATE Register 2 (XGR2)
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-10. XGR2 Field Descriptions
Field
15–0
XGR2[15:0]
6.3.1.11
Description
XGATE Register 2 — The RISC core’s register 2
XGATE Register 3 (XGR3)
The XGR3 register (Figure 6-14) provides access to the RISC core’s register 3.
15
14
13
12
11
10
9
8
R
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
XGR3
W
Reset
7
0
0
0
0
0
0
0
0
Figure 6-14. XGATE Register 3 (XGR3)
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-11. XGR3 Field Descriptions
Field
15–0
XGR3[15:0]
Description
XGATE Register 3 — The RISC core’s register 3
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
199
Chapter 6 XGATE (S12XGATEV2)
6.3.1.12
XGATE Register 4 (XGR4)
The XGR4 register (Figure 6-15) provides access to the RISC core’s register 4.
15
14
13
12
11
10
9
8
R
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
XGR4
W
Reset
7
0
0
0
0
0
0
0
0
Figure 6-15. XGATE Register 4 (XGR4)
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-12. XGR4 Field Descriptions
Field
15–0
XGR4[15:0]
6.3.1.13
Description
XGATE Register 4 — The RISC core’s register 4
XGATE Register 5 (XGR5)
The XGR5 register (Figure 6-16) provides access to the RISC core’s register 5.
15
14
13
12
11
10
9
8
R
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
XGR5
W
Reset
7
0
0
0
0
0
0
0
0
Figure 6-16. XGATE Register 5 (XGR5)
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-13. XGR5 Field Descriptions
Field
15–0
XGR5[15:0]
Description
XGATE Register 5 — The RISC core’s register 5
MC9S12XDP512 Data Sheet, Rev. 2.21
200
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.3.1.14
XGATE Register 6 (XGR6)
The XGR6 register (Figure 6-17) provides access to the RISC core’s register 6.
15
14
13
12
11
10
9
8
R
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
XGR6
W
Reset
7
0
0
0
0
0
0
0
0
Figure 6-17. XGATE Register 6 (XGR6)
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-14. XGR6 Field Descriptions
Field
15–0
XGR6[15:0]
6.3.1.15
Description
XGATE Register 6 — The RISC core’s register 6
XGATE Register 7 (XGR7)
The XGR7 register (Figure 6-18) provides access to the RISC core’s register 7.
15
14
13
12
11
10
9
8
R
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
XGR7
W
Reset
7
0
0
0
0
0
0
0
0
Figure 6-18. XGATE Register 7 (XGR7)
Read: In debug mode if unsecured
Write: In debug mode if unsecured
Table 6-15. XGR7 Field Descriptions
Field
15–0
XGR7[15:0]
Description
XGATE Register 7 — The RISC core’s register 7
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
201
Chapter 6 XGATE (S12XGATEV2)
6.4
Functional Description
The core of the XGATE module is a RISC processor which is able to access the MCU’s internal memories
and peripherals (see Figure 6-1). The RISC processor always remains in an idle state until it is triggered
by an XGATE request. Then it executes a code sequence that is associated with the request and optionally
triggers an interrupt to the S12X_CPU upon completion. Code sequences are not interruptible. A new
XGATE request can only be serviced when the previous sequence is finished and the RISC core becomes
idle.
The XGATE module also provides a set of hardware semaphores which are necessary to ensure data
consistency whenever RAM locations or peripherals are shared with the S12X_CPU.
The following sections describe the components of the XGATE module in further detail.
6.4.1
XGATE RISC Core
The RISC core is a 16 bit processor with an instruction set that is well suited for data transfers, bit
manipulations, and simple arithmetic operations (see Section 6.8, “Instruction Set”).
It is able to access the MCU’s internal memories and peripherals without blocking these resources from
the S12X_CPU1. Whenever the S12X_CPU and the RISC core access the same resource, the RISC core
will be stalled until the resource becomes available again1.
The XGATE offers a high access rate to the MCU’s internal RAM. Depending on the bus load, the RISC
core can perform up to two RAM accesses per S12X_CPU bus cycle.
Bus accesses to peripheral registers or flash are slower. A transfer rate of one bus access per S12X_CPU
cycle can not be exceeded.
The XGATE module is intended to execute short interrupt service routines that are triggered by peripheral
modules or by software.
6.4.2
Programmer’s Model
Register Block
15
15
R7
R6
15
R5
15
R4
Program Counter
0
PC
0
0
0
0
15
R3
15
R2
15
R1(Variable Pointer)
15
15
0
Condition
Code
Register
NZVC
3 2 1 0
0
0
R0 = 0
0
Figure 6-19. Programmer’s Model
1. With the exception of PRR registers (see Section “S12X_MMC”).
MC9S12XDP512 Data Sheet, Rev. 2.21
202
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
The programmer’s model of the XGATE RISC core is shown in Figure 6-19. The processor offers a set of
seven general purpose registers (R1 - R7), which serve as accumulators and index registers. An additional
eighth register (R0) is tied to the value “$0000”. Register R1 has an additional functionality. It is preloaded
with the initial variable pointer of the channel’s service request vector (see Figure 6-20). The initial content
of the remaining general purpose registers is undefined.
The 16 bit program counter allows the addressing of a 64 kbyte address space.
The condition code register contains four bits: the sign bit (S), the zero flag (Z), the overflow flag (V), and
the carry bit (C). The initial content of the condition code register is undefined.
6.4.3
Memory Map
The XGATE’s RISC core is able to access an address space of 64K bytes. The allocation of memory blocks
within this address space is determined on chip level. Refer to the S12X_MMC Section for a detailed
information.
The XGATE vector block assigns a start address and a variable pointer to each XGATE channel. Its
position in the XGATE memory map can be adjusted through the XGVBR register (see Section 6.3.1.3,
“XGATE Vector Base Address Register (XGVBR)”). Figure 6-20 shows the layout of the vector block.
Each vector consists of two 16 bit words. The first contains the start address of the service routine. This
value will be loaded into the program counter before a service routine is executed. The second word is a
pointer to the service routine’s variable space. This value will be loaded into register R1 before a service
routine is executed.
XGVBR
+$0000
unused
Code
+$0024
Channel $09 Initial Program Counter
Channel $09 Initial Variable Pointer
+$0028
Channel $0A Initial Program Counter
Variables
Channel $0A Initial Variable Pointer
+$002C
Channel $0B Initial Program Counter
Channel $0B Initial Variable Pointer
+$0030
Channel $0C Initial Program Counter
Code
Channel $0C Initial Variable Pointer
+$01E0
Channel $78 Initial Program Counter
Variables
Channel $78 Initial Variable Pointer
Figure 6-20. XGATE Vector Block
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
203
Chapter 6 XGATE (S12XGATEV2)
6.4.4
Semaphores
The XGATE module offers a set of eight hardware semaphores. These semaphores provide a mechanism
to protect system resources that are shared between two concurrent threads of program execution; one
thread running on the S12X_CPU and one running on the XGATE RISC core.
Each semaphore can only be in one of the three states: “Unlocked”, “Locked by S12X_CPU”, and “Locked
by XGATE”. The S12X_CPU can check and change a semaphore’s state through the XGATE semaphore
register (XGSEM, see Section 6.3.1.6, “XGATE Semaphore Register (XGSEM)”). The RISC core does
this through its SSEM and CSEM instructions.
Figure 6-21 illustrates the valid state transitions.
%1 ⇒ XGSEM
%0 ⇒ XGSEM
SSEM Instruction
LOCKED BY
S12X_CPU
LOCKED BY
XGATE
M
SE
XG
EM
⇒
0
.
GS
%
EM str
X
r
⇒ o GS In
X M
1
%
⇒ E
1 SS
% nd
a
In CS
st E
ru M
ct
In SS
io
st E
n
ru M
ct
io
n
%1 ⇒ XGSEM
SSEM Instruction
CSEM Instruction
UNLOCKED
%0 ⇒ XGSEM
CSEM Instruction
Figure 6-21. Semaphore State Transitions
MC9S12XDP512 Data Sheet, Rev. 2.21
204
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
Figure 6-22 gives an example of the typical usage of the XGATE hardware semaphores.
Two concurrent threads are running on the system. One is running on the S12X_CPU and the other is
running on the RISC core. They both have a critical section of code that accesses the same system resource.
To guarantee that the system resource is only accessed by one thread at a time, the critical code sequence
must be embedded in a semaphore lock/release sequence as shown.
S12X_CPU
.........
XGATE
.........
%1 ⇒ XGSEMx
SSEM
XGSEM ≡ %1?
BCC?
critical
code
sequence
critical
code
sequence
XGSEM ⇒ %0
CSEM
.........
.........
Figure 6-22. Algorithm for Locking and Releasing Semaphores
6.4.5
Software Error Detection
The XGATE module will immediately terminate program execution after detecting an error condition
caused by erratic application code. There are three error conditions:
• Execution of an illegal opcode
• Illegal vector or opcode fetches
• Illegal load or store accesses
All opcodes which are not listed in section Section 6.8, “Instruction Set” are illegal opcodes. Illegal vector
and opcode fetches as well as illegal load and store accesses are defined on chip level. Refer to the
S12X_MMC Section for a detailed information.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
205
Chapter 6 XGATE (S12XGATEV2)
6.5
6.5.1
Interrupts
Incoming Interrupt Requests
XGATE threads are triggered by interrupt requests which are routed to the XGATE module (see
S12X_INT Section). Only a subset of the MCU’s interrupt requests can be routed to the XGATE. Which
specific interrupt requests these are and which channel ID they are assigned to is documented in Section
“Interrupts” of the SoC Guide.
6.5.2
Outgoing Interrupt Requests
There are three types of interrupt requests which can be triggered by the XGATE module:
4. Channel interrupts
For each XGATE channel there is an associated interrupt flag in the XGATE interrupt flag vector
(XGIF, see Section 6.3.1.4, “XGATE Channel Interrupt Flag Vector (XGIF)”). These flags can be
set through the "SIF" instruction by the RISC core. They are typically used to flag an interrupt to
the S12X_CPU when the XGATE has completed one of its tasks.
5. Software triggers
Software triggers are interrupt flags, which can be set and cleared by software (see Section 6.3.1.5,
“XGATE Software Trigger Register (XGSWT)”). They are typically used to trigger XGATE tasks
by the S12X_CPU software. However these interrupts can also be routed to the S12X_CPU (see
S12X_INT Section) and triggered by the XGATE software.
6. Software error interrupt
The software error interrupt signals to the S12X_CPU the detection of an error condition in the
XGATE application code (see Section 6.4.5, “Software Error Detection”).
All XGATE interrupts can be disabled by the XGIE bit in the XGATE module control register (XGMCTL,
see Section 6.3.1.1, “XGATE Control Register (XGMCTL)”).
6.6
Debug Mode
The XGATE debug mode is a feature to allow debugging of application code.
6.6.1
Debug Features
In debug mode the RISC core will be halted and the following debug features will be enabled:
• Read and Write accesses to RISC core registers (XGCCR, XGPC, XGR1–XGR7)1
All RISC core registers can be modified. Leaving debug mode will cause the RISC core to continue
program execution with the modified register values.
1. Only possible if MCU is unsecured
MC9S12XDP512 Data Sheet, Rev. 2.21
206
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
•
•
6.6.2
Single Stepping
Writing a "1" to the XGSS bit will call the RISC core to execute a single instruction. All RISC core
registers will be updated accordingly.
Write accesses to the XGCHID register
Three operations can be performed by writing to the XGCHID register:
– Change of channel ID
If a non-zero value is written to the XGCHID while a thread is active (XGCHID ≠ $00), then
the current channel ID will be changed without any influence on the program counter or the
other RISC core registers.
– Start of a thread
If a non-zero value is written to the XGCHID while the XGATE is idle (XGCHID = $00),
then the thread that is associated with the new channel ID will be executed upon leaving
debug mode.
– Termination of a thread
If zero is written to the XGCHID while a thread is active (XGCHID ≠ $00), then the current
thread will be terminated and the XGATE will become idle.
Entering Debug Mode
Debug mode can be entered in four ways:
1. Setting XGDBG to "1"
Writing a "1" to XGDBG and XGDBGM in the same write access causes the XGATE to enter
debug mode upon completion of the current instruction.
NOTE
After writing to the XGDBG bit the XGATE will not immediately enter
debug mode. Depending on the instruction that is executed at this time there
may be a delay of several clock cycles. The XGDBG will read "0" until
debug mode is entered.
2. Software breakpoints
XGATE programs which are stored in the internal RAM allow the use of software breakpoints. A
software breakpoint is set by replacing an instruction of the program code with the "BRK"
instruction.
As soon as the program execution reaches the "BRK" instruction, the XGATE enters debug mode.
Additionally a software breakpoint request is sent to the S12X_DBG module (see section 4.9 of
the S12X_DBG Section).
Upon entering debug mode, the program counter will point to the "BRK" instruction. The other
RISC core registers will hold the result of the previous instruction.
To resume program execution, the "BRK" instruction must be replaced by the original instruction
before leaving debug mode.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
207
Chapter 6 XGATE (S12XGATEV2)
3. Tagged Breakpoints
The S12X_DBG module is able to place tags on fetched opcodes. The XGATE is able to enter
debug mode right before a tagged opcode is executed (see section 4.9 of the S12X_DBG Section).
Upon entering debug mode, the program counter will point to the tagged instruction. The other
RISC core registers will hold the result of the previous instruction.
4. Forced Breakpoints
Forced breakpoints are triggered by the S12X_DBG module (see section 4.9 of the S12X_DBG
Section). When a forced breakpoint occurs, the XGATE will enter debug mode upon completion
of the current instruction.
6.6.3
Leaving Debug Mode
Debug mode can only be left by setting the XGDBG bit to "0". If a thread is active (XGCHID has not been
cleared in debug mode), program execution will resume at the value of XGPC.
6.7
Security
In order to protect XGATE application code on secured S12X devices, a few restrictions in the debug
features have been made. These are:
• Registers XGCCR, XGPC, and XGR1–XGR7 will read zero on a secured device
• Registers XGCCR, XGPC, and XGR1–XGR7 can not be written on a secured device
• Single stepping is not possible on a secured device
6.8
6.8.1
Instruction Set
Addressing Modes
For the ease of implementation the architecture is a strict Load/Store RISC machine, which means all
operations must have one of the eight general purpose registers R0 … R7 as their source as well their
destination.
All word accesses must work with a word aligned address, that is A[0] = 0!
MC9S12XDP512 Data Sheet, Rev. 2.21
208
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.8.1.1
Naming Conventions
RD
RD.L
RD.H
RS, RS1, RS2
RS.L, RS1.L, RS2.L
RS.H, RS1.H, RS2.H
RB
RI
RI+
–RI
Destination register, allowed range is R0–R7
Low byte of the destination register, bits [7:0]
High byte of the destination register, bits [15:8]
Source register, allowed range is R0–R7
Low byte of the source register, bits [7:0]
High byte of the source register, bits[15:8]
Base register for indexed addressing modes, allowed
range is R0–R7
Offset register for indexed addressing modes with
register offset, allowed range is R0–R7
Offset register for indexed addressing modes with
register offset and post-increment,
Allowed range is R0–R7 (R0+ is equivalent to R0)
Offset register for indexed addressing modes with
register offset and pre-decrement,
Allowed range is R0–R7 (–R0 is equivalent to R0)
NOTE
Even though register R1 is intended to be used as a pointer to the variable
segment, it may be used as a general purpose data register as well.
Selecting R0 as destination register will discard the result of the instruction.
Only the condition code register will be updated
6.8.1.2
Inherent Addressing Mode (INH)
Instructions that use this addressing mode either have no operands or all operands are in internal XGATE
registers:.
Examples
BRK
RTS
6.8.1.3
Immediate 3-Bit Wide (IMM3)
Operands for immediate mode instructions are included in the instruction stream and are fetched into the
instruction queue along with the rest of the 16 bit instruction. The ’#’ symbol is used to indicate an
immediate addressing mode operand. This address mode is used for semaphore instructions.
Examples:
CSEM
SSEM
#1
#3
; Unlock semaphore 1
; Lock Semaphore 3
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
209
Chapter 6 XGATE (S12XGATEV2)
6.8.1.4
Immediate 4 Bit Wide (IMM4)
The 4 bit wide immediate addressing mode is supported by all shift instructions.
RD = RD ∗ imm4
Examples:
LSL
LSR
6.8.1.5
R4,#1
R4,#3
; R4 = R4 << 1; shift register R4 by 1 bit to the left
; R4 = R4 >> 3; shift register R4 by 3 bits to the right
Immediate 8 Bit Wide (IMM8)
The 8 bit wide immediate addressing mode is supported by four major commands (ADD, SUB, LD, CMP).
RD = RD ∗ imm8
Examples:
ADDL
SUBL
LDH
CMPL
6.8.1.6
R1,#1
R2,#2
R3,#3
R4,#4
;
;
;
;
adds an 8 bit value to register R1
subtracts an 8 bit value from register R2
loads an 8 bit immediate into the high byte of Register R3
compares the low byte of register R4 with an immediate value
Immediate 16 Bit Wide (IMM16)
The 16 bit wide immediate addressing mode is a construct to simplify assembler code. Instructions which
offer this mode are translated into two opcodes using the eight bit wide immediate addressing mode.
RD = RD ∗ imm16
Examples:
LDW
ADD
6.8.1.7
R4,#$1234
R4,#$5678
; translated to LDL R4,#$34; LDH R4,#$12
; translated to ADDL R4,#$78; ADDH R4,#$56
Monadic Addressing (MON)
In this addressing mode only one operand is explicitly given. This operand can either be the source (f(RD)),
the target (RD = f()), or both source and target of the operation (RD = f(RD)).
Examples:
JAL
SIF
R1
R2
; PC = R1, R1 = PC+2
; Trigger IRQ associated with the channel number in R2.L
MC9S12XDP512 Data Sheet, Rev. 2.21
210
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.8.1.8
Dyadic Addressing (DYA)
In this mode the result of an operation between two registers is stored in one of the registers used as
operands.
RD = RD ∗ RS is the general register to register format, with register RD being the first operand and RS
the second. RD and RS can be any of the 8 general purpose registers R0 … R7. If R0 is used as the
destination register, only the condition code flags are updated. This addressing mode is used only for shift
operations with a variable shift value
Examples:
LSL
LSR
6.8.1.9
R4,R5
R4,R5
; R4 = R4 << R5
; R4 = R4 >> R5
Triadic Addressing (TRI)
In this mode the result of an operation between two or three registers is stored into a third one.
RD = RS1 ∗ RS2 is the general format used in the order RD, RS1, RS1. RD, RS1, RS2 can be any of the
8 general purpose registers R0 … R7. If R0 is used as the destination register RD, only the condition code
flags are updated. This addressing mode is used for all arithmetic and logical operations.
Examples:
ADC
SUB
6.8.1.10
R5,R6,R7
R5,R6,R7
; R5 = R6 + R7 + Carry
; R5 = R6 - R7
Relative Addressing 9-Bit Wide (REL9)
A 9-bit signed word address offset is included in the instruction word. This addressing mode is used for
conditional branch instructions.
Examples:
BCC
BEQ
6.8.1.11
REL9
REL9
; PC = PC + 2 + (REL9 << 1)
; PC = PC + 2 + (REL9 << 1)
Relative Addressing 10-Bit Wide (REL10)
An 11-bit signed word address offset is included in the instruction word. This addressing mode is used for
the unconditional branch instruction.
Examples:
BRA
6.8.1.12
REL10
; PC = PC + 2 + (REL10 << 1)
Index Register plus Immediate Offset (IDO5)
(RS, #offset5) provides an unsigned offset from the base register.
Examples:
LDB
STW
R4,(R1,#offset)
R4,(R1,#offset)
; loads a byte from R1+offset into R4
; stores R4 as a word to R1+offset
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
211
Chapter 6 XGATE (S12XGATEV2)
6.8.1.13
Index Register plus Register Offset (IDR)
For load and store instructions (RS, RI) provides a variable offset in a register.
Examples:
LDB
STW
6.8.1.14
R4,(R1,R2)
R4,(R1,R2)
; loads a byte from R1+R2 into R4
; stores R4 as a word to R1+R2
Index Register plus Register Offset with Post-increment (IDR+)
[RS, RI+] provides a variable offset in a register, which is incremented after accessing the memory. In case
of a byte access the index register will be incremented by one. In case of a word access it will be
incremented by two.
Examples:
LDB
STW
6.8.1.15
R4,(R1,R2+)
R4,(R1,R2+)
; loads a byte from R1+R2 into R4, R2+=1
; stores R4 as a word to R1+R2, R2+=2
Index Register plus Register Offset with Pre-decrement (–IDR)
[RS, -RI] provides a variable offset in a register, which is decremented before accessing the memory. In
case of a byte access the index register will be decremented by one. In case of a word access it will be
decremented by two.
Examples:
LDB
STW
6.8.2
R4,(R1,-R2)
R4,(R1,-R2)
; R2 -=1, loads a byte from R1+R2 into R4
; R2 -=2, stores R4 as a word to R1+R2
Instruction Summary and Usage
6.8.2.1
Load & Store Instructions
Any register can be loaded either with an immediate or from the address space using indexed addressing
modes.
LDL
LDW
RD,#IMM8
RD,(RB,RI)
; loads an immediate 8 bit value to the lower byte of RD
; loads data using RB+RI as effective address
LDB
RD,(RB, RI+)
; loads data using RB+RI as effective address
; followed by an increment of RI depending on
; the size of the operation
The same set of modes is available for the store instructions
STB
RS,(RB, RI)
; stores data using RB+RI as effective address
STW
RS,(RB, RI+)
; stores data using RB+RI as effective address
; followed by an increment of RI depending on
; the size of the operation.
MC9S12XDP512 Data Sheet, Rev. 2.21
212
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.8.2.2
Logic and Arithmetic Instructions
All logic and arithmetic instructions support the 8 bit immediate addressing mode (IMM8: RD = RD ∗
#IMM8) and the triadic addressing mode (TRI: RD = RS1 ∗ RS2).
All arithmetic is considered as signed, sign, overflow, zero and carry flag will be updated. The carry will
not be affected for logical operations.
ADDL
ANDH
R2,#1
R4,#$FE
; increment R2
; R4.H = R4.H & $FE, clear lower bit of higher byte
ADD
SUB
R3,R4,R5
R3,R4,R5
; R3 = R4 + R5
; R3 = R4 - R5
AND
OR
R3,R4,R5
R3,R4,R5
; R3 = R4 & R5 logical AND on the whole word
; R3 = R4 | R5
6.8.2.3
Register – Register Transfers
This group comprises transfers from and to some special registers
TFR
R3,CCR
; transfers the condition code register to the low byte of
; register R3
Branch Instructions
The branch offset is +255 words or -256 words counted from the beginning of the next instruction. Since
instructions have a fixed 16 bit width, the branch offsets are word aligned by shifting the offset value by 2.
BEQ
label
; if Z flag = 1 branch to label
An unconditional branch allows a +511 words or -512 words branch distance.
BRA
6.8.2.4
label
Shift Instructions
Shift operations allow the use of a 4 bit wide immediate value to identify a shift width within a 16 bit word.
For shift operations a value of 0 does not shift at all, while a value of 15 shifts the register RD by 15 bits.
In a second form the shift value is contained in the bits 3:0 of the register RS.
Examples:
LSL
LSR
ASR
R4,#1
R4,#3
R4,R2
; R4 = R4 << 1; shift register R4 by 1 bit to the left
; R4 = R4 >> 3; shift register R4 by 3 bits to the right
; R4 = R4 >> R2;arithmetic shift register R4 right by the amount
;
of bits contained in R2[3:0].
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
213
Chapter 6 XGATE (S12XGATEV2)
6.8.2.5
Bit Field Operations
This addressing mode is used to identify the position and size of a bit field for insertion or extraction. The
width and offset are coded in the lower byte of the source register 2, RS2. The content of the upper byte is
ignored. An offset of 0 denotes the right most position and a width of 0 denotes 1 bit. These instructions
are very useful to extract, insert, clear, set or toggle portions of a 16 bit word.
W4
O4
5
2
W4=3, O4=2
15
RS2
0
RS1
Bit Field Extract
Bit Field Insert
15
3
0
RD
Figure 6-23. Bit Field Addressing
BFEXT
6.8.2.6
R3,R4,R5 ; R5: W4 bits offset O4, will be extracted from R4 into R3
Special Instructions for DMA Usage
The XGATE offers a number of additional instructions for flag manipulation, program flow control and
debugging:
1. SIF: Set a channel interrupt flag
2. SSEM: Test and set a hardware semaphore
3. CSEM: Clear a hardware semaphore
4. BRK: Software breakpoint
5. NOP: No Operation
6. RTS: Terminate the current thread
MC9S12XDP512 Data Sheet, Rev. 2.21
214
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.8.3
Cycle Notation
Table 6-16 show the XGATE access detail notation. Each code letter equals one XGATE cycle. Each letter
implies additional wait cycles if memories or peripherals are not accessible. Memories or peripherals are
not accessible if they are blocked by the S12X_CPU. In addition to this Peripherals are only accessible
every other XGATE cycle. Uppercase letters denote 16 bit operations. Lowercase letters denote 8 bit
operations. The XGATE is able to perform two bus or wait cycles per S12X_CPU cycle.
Table 6-16. Access Detail Notation
V — Vector fetch: always an aligned word read, lasts for at least one RISC core cycle
P — Program word fetch: always an aligned word read, lasts for at least one RISC core cycle
r — 8 bit data read: lasts for at least one RISC core cycle
R — 16 bit data read: lasts for at least one RISC core cycle
w — 8 bit data write: lasts for at least one RISC core cycle
W — 16 bit data write: lasts for at least one RISC core cycle
A — Alignment cycle: no read or write, lasts for zero or one RISC core cycles
f — Free cycle: no read or write, lasts for one RISC core cycles
Special Cases
PP/P — Branch: PP if branch taken, P if not
6.8.4
Thread Execution
When the RISC core is triggered by an interrupt request (see Figure 6-1) it first executes a vector fetch
sequence which performs three bus accesses:
1. A V-cycle to fetch the initial content of the program counter.
2. A V-cycle to fetch the initial content of the data segment pointer (R1).
3. A P-cycle to load the initial opcode.
Afterwards a sequence of instructions (thread) is executed which is terminated by an "RTS" instruction. If
further interrupt requests are pending after a thread has been terminated, a new vector fetch will be
performed. Otherwise the RISC core will idle until a new interrupt request is received. A thread can not be
interrupted by an interrupt request.
6.8.5
Instruction Glossary
This section describes the XGATE instruction set in alphabetical order.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
215
Chapter 6 XGATE (S12XGATEV2)
ADC
ADC
Add with Carry
Operation
RS1 + RS2 + C ⇒ RD
Adds the content of register RS1, the content of register RS2 and the value of the Carry bit using binary
addition and stores the result in the destination register RD. The Zero Flag is also carried forward from the
previous operation allowing 32 and more bit additions.
Example:
ADC
ADC
BCC
R6,R2,R2
R7,R3,R3 ; R7:R6 = R5:R4 + R3:R2
; conditional branch on 32 bit addition
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Set if bit 15 of the result is set; cleared otherwise.
Z:
Set if the result is $0000 and Z was set before this operation; cleared otherwise.
V:
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS1[15] & RS2[15] & RD[15]new | RS1[15] & RS2[15] & RD[15]new
C:
Set if there is a carry from bit 15 of the result; cleared otherwise.
RS1[15] & RS2[15] | RS1[15] & RD[15]new | RS2[15] & RD[15]new
Code and CPU Cycles
Source Form
ADC RD, RS1, RS2
Address
Mode
TRI
Machine Code
0
0
0
1
1
RD
RS1
Cycles
RS2
1
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
216
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
ADD
ADD
Add without Carry
Operation
RS1 + RS2 ⇒ RD
RD + IMM16 ⇒ RD (translates to ADDL RD, #IMM16[7:0]; ADDH RD, #[15:8])
Performs a 16 bit addition and stores the result in the destination register RD.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS1[15] & RS2[15] & RD[15]new | RS1[15] & RS2[15] & RD[15]new
Refer to ADDH instruction for #IMM16 operations.
Set if there is a carry from bit 15 of the result; cleared otherwise.
RS1[15] & RS2[15] | RS1[15] & RD[15]new | RS2[15] & RD[15]new
Refer to ADDH instruction for #IMM16 operations.
Code and CPU Cycles
Source Form
Address
Mode
Machine Code
RS1
Cycles
ADD RD, RS1, RS2
TRI
0
0
0
1
1
RD
RS2
1
0
P
ADD RD, #IMM16
IMM8
1
1
1
0
0
RD
IMM16[7:0]
P
IMM8
1
1
1
0
1
RD
IMM16[15:8]
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
217
Chapter 6 XGATE (S12XGATEV2)
ADDH
ADDH
Add Immediate 8 bit Constant
(High Byte)
Operation
RD + IMM8:$00 ⇒ RD
Adds the content of high byte of register RD and a signed immediate 8 bit constant using binary addition
and stores the result in the high byte of the destination register RD. This instruction can be used after an
ADDL for a 16 bit immediate addition.
Example:
ADDL
ADDH
R2,#LOWBYTE
R2,#HIGHBYTE
; R2 = R2 + 16 bit immediate
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RD[15]old & IMM8[7] & RD[15]new | RD[15]old & IMM8[7] & RD[15]new
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RD[15]old & IMM8[7] | RD[15]old & RD[15]new | IMM8[7] & RD[15]new
Code and CPU Cycles
Source Form
ADDH RD, #IMM8
Address
Mode
IMM8
Machine Code
1
1
1
0
1
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
218
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
ADDL
Add Immediate 8 bit Constant
(Low Byte)
ADDL
Operation
RD + $00:IMM8 ⇒ RD
Adds the content of register RD and an unsigned immediate 8 bit constant using binary addition and stores
the result in the destination register RD. This instruction must be used first for a 16 bit immediate addition
in conjunction with the ADDH instruction.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the 8 bit operation; cleared otherwise.
RD[15]old & RD[15]new
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RD[15]old & RD[15]new
Code and CPU Cycles
Source Form
ADDL RD, #IMM8
Address
Mode
IMM8
Machine Code
1
1
1
0
0
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
219
Chapter 6 XGATE (S12XGATEV2)
AND
AND
Logical AND
Operation
RS1 & RS2 ⇒ RD
RD & IMM16 ⇒ RD (translates to ANDL RD, #IMM16[7:0]; ANDH RD, #IMM16[15:8])
Performs a bit wise logical AND of two 16 bit values and stores the result in the destination register RD.
Remark: There is no complement to the BITH and BITL functions. This can be imitated by using R0 as a
destination register. AND R0, RS1, RS2 performs a bit wise test without storing a result.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Refer to ANDH instruction for #IMM16 operations.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
AND RD, RS1, RS2
AND RD, #IMM16
Address
Mode
Machine Code
RS1
Cycles
TRI
0
0
0
1
0
RD
RS2
0
0
P
IMM8
1
0
0
0
0
RD
IMM16[7:0]
P
IMM8
1
0
0
0
1
RD
IMM16[15:8]
P
MC9S12XDP512 Data Sheet, Rev. 2.21
220
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
ANDH
Logical AND Immediate 8 bit Constant
(High Byte)
ANDH
Operation
RD.H & IMM8 ⇒ RD.H
Performs a bit wise logical AND between the high byte of register RD and an immediate 8 bit constant and
stores the result in the destination register RD.H. The low byte of RD is not affected.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
ANDH RD, #IMM8
Address
Mode
IMM8
Machine Code
1
0
0
0
1
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
221
Chapter 6 XGATE (S12XGATEV2)
ANDL
Logical AND Immediate 8 bit Constant
(Low Byte)
ANDL
Operation
RD.L & IMM8 ⇒ RD.L
Performs a bit wise logical AND between the low byte of register RD and an immediate 8 bit constant and
stores the result in the destination register RD.L. The high byte of RD is not affected.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 7 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
ANDL RD, #IMM8
Address
Mode
IMM8
Machine Code
1
0
0
0
0
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
222
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
ASR
ASR
Arithmetic Shift Right
Operation
n
b15
RD
C
n = RS or IMM4
Shifts the bits in register RD n positions to the right. The higher n bits of the register RD become filled
with the sign bit (RD[15]). The carry flag will be updated to the bit contained in RD[n-1] before the shift
for n > 0.
n can range from 0 to 16.
In immediate address mode, n is determined by the operand IMM4. n is considered to be 16 in IMM4 is
equal to 0.
In dyadic address mode, n is determined by the content of RS. n is considered to be 16 if the content of RS
is greater than 15.
CCR Effects
N
Z
V
C
∆
∆
0
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RD[15]old ^ RD[15]new
Set if n > 0 and RD[n-1] = 1; if n = 0 unaffected.
Code and CPU Cycles
Source Form
ASR RD, #IMM4
ASR RD, RS
Address
Mode
Machine Code
IMM4
0
0
0
0
1
RD
IMM4
DYA
0
0
0
0
1
RD
RS
Cycles
1
1
0
0
1
P
0
0
0
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
223
Chapter 6 XGATE (S12XGATEV2)
BCC
BCC
Branch if Carry Cleared
(Same as BHS)
Operation
If C = 0, then PC + $0002 + (REL9 << 1) ⇒ PC
Tests the Carry flag and branches if C = 0.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BCC REL9
Address
Mode
REL9
Machine Code
0
0
1
0
0
0
0
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
224
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BCS
BCS
Branch if Carry Set
(Same as BLO)
Operation
If C = 1, then PC + $0002 + (REL9 << 1) ⇒ PC
Tests the Carry flag and branches if C = 1.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BCS REL9
Address
Mode
REL9
Machine Code
0
0
1
0
0
0
1
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
225
Chapter 6 XGATE (S12XGATEV2)
BEQ
BEQ
Branch if Equal
Operation
If Z = 1, then PC + $0002 + (REL9 << 1) ⇒ PC
Tests the Zero flag and branches if Z = 1.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BEQ REL9
Address
Mode
REL9
Machine Code
0
0
1
0
0
1
1
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
226
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BFEXT
BFEXT
Bit Field Extract
Operation
RS1[(o+w):o] ⇒ RD[w:0]; 0 ⇒ RD[15:(w+1)]
w = (RS2[7:4])
o = (RS2[3:0])
Extracts w+1 bits from register RS1 starting at position o and writes them right aligned into register RD.
The remaining bits in RD will be cleared. If (o+w) > 15 only bits [15:o] get extracted.
15
7
4
3
0
W4
15
O4
5
2
RS2
0
W4=3, O4=2
RS1
Bit Field Extract
15
3
0
0
RD
CCR Effects
N
Z
V
C
0
∆
0
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
BFEXT RD, RS1, RS2
Address
Mode
TRI
Machine Code
0
1
1
0
0
RD
RS1
Cycles
RS2
1
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
227
Chapter 6 XGATE (S12XGATEV2)
BFFO
BFFO
Bit Field Find First One
Operation
FirstOne (RS) ⇒ RD;
Searches the first “1” in register RS (from MSB to LSB) and writes the bit position into the destination
register RD. The upper bits of RD are cleared. In case the content of RS is equal to $0000, RD will be
cleared and the carry flag will be set. This is used to distinguish a “1” in position 0 versus no “1” in the
whole RS register at all.
CCR Effects
N
Z
V
C
0
∆
0
∆
N:
Z:
V:
C:
1
0; cleared.
Set if the result is $0000; cleared otherwise.
0; cleared.
Set if RS = $00001; cleared otherwise.
Before executing the instruction
Code and CPU Cycles
Source Form
BFFO RD, RS
Address
Mode
DYA
Machine Code
0
0
0
0
1
RD
RS
Cycles
1
0
0
0
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
228
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BFINS
BFINS
Bit Field Insert
Operation
RS1[w:0] ⇒ RD[(w+o):o];
w = (RS2[7:4])
o = (RS2[3:0])
Extracts w+1 bits from register RS1 starting at position 0 and writes them into register RD starting at
position o. The remaining bits in RD are not affected. If (o+w) > 15 the upper bits are ignored. Using R0
as a RS1, this command can be used to clear bits.
15
7
4
3
0
W4
O4
15
3
RS2
0
RS1
Bit Field Insert
15
5
2
0
W4=3, O4=2
RD
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
BFINS RD, RS1, RS2
Address
Mode
TRI
Machine Code
0
1
1
0
1
RD
RS1
Cycles
RS2
1
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
229
Chapter 6 XGATE (S12XGATEV2)
BFINSI
BFINSI
Bit Field Insert and Invert
Operation
!RS1[w:0] ⇒ RD[w+o:o];
w = (RS2[7:4])
o = (RS2[3:0])
Extracts w+1 bits from register RS1 starting at position 0, inverts them and writes into register RD starting
at position o. The remaining bits in RD are not affected. If (o+w) > 15 the upper bits are ignored. Using
R0 as a RS1, this command can be used to set bits.
15
7
4
3
0
W4
O4
15
RS2
3
0
RS1
Inverted Bit Field Insert
15
5
2
W4=3, O4=2
0
RD
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
BFINSI RD, RS1, RS2
Address
Mode
TRI
Machine Code
0
1
1
1
0
RD
RS1
Cycles
RS2
1
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
230
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BFINSX
BFINSX
Bit Field Insert and XNOR
Operation
!(RS1[w:0] ^ RD[w+o:o]) ⇒ RD[w+o:o];
w = (RS2[7:4])
o = (RS2[3:0])
Extracts w+1 bits from register RS1 starting at position 0, performs an XNOR with RD[w+o:o] and writes
the bits back io RD. The remaining bits in RD are not affected. If (o+w) > 15 the upper bits are ignored.
Using R0 as a RS1, this command can be used to toggle bits.
15
7
4
3
0
W4
O4
15
RS2
3
0
RS1
Bit Field Insert XNOR
15
5
2
W4=3, O4=2
0
RD
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
BFINSX RD, RS1, RS2
Address
Mode
TRI
Machine Code
0
1
1
1
1
RD
RS1
Cycles
RS2
1
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
231
Chapter 6 XGATE (S12XGATEV2)
BGE
BGE
Branch if Greater than or Equal to Zero
Operation
If N ^ V = 0, then PC + $0002 + (REL9 << 1) ⇒ PC
Branch instruction to compare signed numbers.
Branch if RS1 ≥ RS2:
SUB
BGE
R0,RS1,RS2
REL9
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BGE REL9
Address
Mode
REL9
Machine Code
0
0
1
1
0
1
0
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
232
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BGT
BGT
Branch if Greater than Zero
Operation
If Z | (N ^ V) = 0, then PC + $0002 + (REL9 << 1) ⇒ PC
Branch instruction to compare signed numbers.
Branch if RS1 > RS2:
SUB
BGE
R0,RS1,RS2
REL9
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BGT REL9
Address
Mode
REL9
Machine Code
0
0
1
1
1
0
0
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
233
Chapter 6 XGATE (S12XGATEV2)
BHI
BHI
Branch if Higher
Operation
If C | Z = 0, then PC + $0002 + (REL9 << 1) ⇒ PC
Branch instruction to compare unsigned numbers.
Branch if RS1 > RS2:
SUB
BHI
R0,RS1,RS2
REL9
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BHI REL9
Address
Mode
REL9
Machine Code
0
0
1
1
0
0
0
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
234
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BHS
BHS
Branch if Higher or Same
(Same as BCC)
Operation
If C = 0, then PC + $0002 + (REL9 << 1) ⇒ PC
Branch instruction to compare unsigned numbers.
Branch if RS1 ≥ RS2:
SUB
BHS
R0,RS1,RS2
REL9
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BHS REL9
Address
Mode
REL9
Machine Code
0
0
1
0
0
0
0
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
235
Chapter 6 XGATE (S12XGATEV2)
BITH
BITH
Bit Test Immediate 8 bit Constant
(High Byte)
Operation
RD.H & IMM8 ⇒ NONE
Performs a bit wise logical AND between the high byte of register RD and an immediate 8 bit constant.
Only the condition code flags get updated, but no result is written back
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
BITH RD, #IMM8
Address
Mode
IMM8
Machine Code
1
0
0
1
1
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
236
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BITL
BITL
Bit Test Immediate 8 bit Constant
(Low Byte)
Operation
RD.L & IMM8 ⇒ NONE
Performs a bit wise logical AND between the low byte of register RD and an immediate 8 bit constant.
Only the condition code flags get updated, but no result is written back.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 7 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
BITL RD, #IMM8
Address
Mode
IMM8
Machine Code
1
0
0
1
0
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
237
Chapter 6 XGATE (S12XGATEV2)
BLE
BLE
Branch if Less or Equal to Zero
Operation
If Z | (N ^ V) = 1, then PC + $0002 + (REL9 << 1) ⇒ PC
Branch instruction to compare signed numbers.
Branch if RS1 ≤ RS2:
SUB
BLE
R0,RS1,RS2
REL9
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BLE REL9
Address
Mode
REL9
Machine Code
0
0
1
1
1
0
1
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
238
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BLO
BLO
Branch if Carry Set
(Same as BCS)
Operation
If C = 1, then PC + $0002 + (REL9 << 1) ⇒ PC
Branch instruction to compare unsigned numbers.
Branch if RS1 < RS2:
SUB
BLO
R0,RS1,RS2
REL9
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BLO REL9
Address
Mode
REL9
Machine Code
0
0
1
0
0
0
1
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
239
Chapter 6 XGATE (S12XGATEV2)
BLS
BLS
Branch if Lower or Same
Operation
If C | Z = 1, then PC + $0002 + (REL9 << 1) ⇒ PC
Branch instruction to compare unsigned numbers.
Branch if RS1 ≤ RS2:
SUB
BLS
R0,RS1,RS2
REL9
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BLS REL9
Address
Mode
REL9
Machine Code
0
0
1
1
0
0
1
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
240
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BLT
BLT
Branch if Lower than Zero
Operation
If N ^ V = 1, then PC + $0002 + (REL9 << 1) ⇒ PC
Branch instruction to compare signed numbers.
Branch if RS1 < RS2:
SUB
BLT
R0,RS1,RS2
REL9
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BLT REL9
Address
Mode
REL9
Machine Code
0
0
1
1
0
1
1
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
241
Chapter 6 XGATE (S12XGATEV2)
BMI
BMI
Branch if Minus
Operation
If N = 1, then PC + $0002 + (REL9 << 1) ⇒ PC
Tests the Sign flag and branches if N = 1.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BMI REL9
Address
Mode
REL9
Machine Code
0
0
1
0
1
0
1
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
242
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BNE
BNE
Branch if Not Equal
Operation
If Z = 0, then PC + $0002 + (REL9 << 1) ⇒ PC
Tests the Zero flag and branches if Z = 0.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BNE REL9
Address
Mode
REL9
Machine Code
0
0
1
0
0
1
0
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
243
Chapter 6 XGATE (S12XGATEV2)
BPL
BPL
Branch if Plus
Operation
If N = 0, then PC + $0002 + (REL9 << 1) ⇒ PC
Tests the Sign flag and branches if N = 0.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BPL REL9
Address
Mode
REL9
Machine Code
0
0
1
0
1
0
0
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
244
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BRA
BRA
Branch Always
Operation
PC + $0002 + (REL10 << 1) ⇒ PC
Branches always
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BRA REL10
Address
Mode
REL10
Machine Code
0
0
1
1
1
1
Cycles
REL10
PP
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
245
Chapter 6 XGATE (S12XGATEV2)
BRK
BRK
Break
Operation
Put XGATE into Debug Mode (see Section 6.6.2, “Entering Debug Mode”)and signals a Software
breakpoint to the S12X_DBG module (see section 4.9 of the S12X_DBG Section).
NOTE
It is not possible to single step over a BRK instruction. This instruction does
not advance the program counter.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BRK
Address
Mode
INH
Machine Code
0
0
0
0
0
0
0
0
0
0
Cycles
0
0
0
0
0
0
PAff
MC9S12XDP512 Data Sheet, Rev. 2.21
246
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
BVC
BVC
Branch if Overflow Cleared
Operation
If V = 0, then PC + $0002 + (REL9 << 1) ⇒ PC
Tests the Overflow flag and branches if V = 0.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BVC REL9
Address
Mode
REL9
Machine Code
0
0
1
0
1
1
0
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
247
Chapter 6 XGATE (S12XGATEV2)
BVS
BVS
Branch if Overflow Set
Operation
If V = 1, then PC + $0002 + (REL9 << 1) ⇒ PC
Tests the Overflow flag and branches if V = 1.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
BVS REL9
Address
Mode
REL9
Machine Code
0
0
1
0
1
1
1
Cycles
REL9
PP/P
MC9S12XDP512 Data Sheet, Rev. 2.21
248
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
CMP
CMP
Compare
Operation
RS2 – RS1
⇒ NONE (translates to SUB R0, RS1, RS2)
RD – IMM16 ⇒ NONE (translates to CMPL RD, #IMM16[7:0]; CPCH RD, #IMM16[15:8])
Subtracts two 16 bit values and discards the result.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS1[15] & RS2[15] & result[15] | RS1[15] & RS2[15] & result[15]
RD[15] & IMM16[15] & result[15] | RD[15] & IMM16[15] & result[15]
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RS1[15] & RS2[15] | RS1[15] & result[15] | RS2[15] & result[15]
RD[15] & IMM16[15] | RD[15] & result[15] | IMM16[15] & result[15]
Code and CPU Cycles
Source Form
CMP RS1, RS2
CMP RS, #IMM16
Address
Mode
Machine Code
0
0
0
RS1
Cycles
TRI
0
0
0
1
1
RS2
0
0
P
IMM8
1
1
0
1
0
RS
IMM16[7:0]
P
IMM8
1
1
0
1
1
RS
IMM16[15:8]
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
249
Chapter 6 XGATE (S12XGATEV2)
CMPL
Compare Immediate 8 bit Constant
(Low Byte)
CMPL
Operation
RS.L – IMM8 ⇒ NONE, only condition code flags get updated
Subtracts the 8 bit constant IMM8 contained in the instruction code from the low byte of the source register
RS.L using binary subtraction and updates the condition code register accordingly.
Remark: There is no equivalent operation using triadic addressing. Comparing the values of two registers
can be performed by using the subtract instruction with R0 as destination register.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 7 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
Set if a two´s complement overflow resulted from the 8 bit operation; cleared otherwise.
RS[7] & IMM8[7] & result[7] | RS[7] & IMM8[7] & result[7]
Set if there is a carry from the Bit 7 to Bit 8 of the result; cleared otherwise.
RS[7] & IMM8[7] | RS[7] & result[7] | IMM8[7] & result[7]
Code and CPU Cycles
Source Form
CMPL RS, #IMM8
Address
Mode
IMM8
Machine Code
1
1
0
1
0
RS
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
250
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
COM
COM
One’s Complement
Operation
~RS ⇒ RD (translates to XNOR RD, R0, RS)
~RD ⇒ RD (translates to XNOR RD, R0, RD)
Performs a one’s complement on a general purpose register.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
Address
Mode
Machine Code
Cycles
COM RD, RS
TRI
0
0
0
1
0
RD
0
0
0
RS
1
1
P
COM RD
TRI
0
0
0
1
0
RD
0
0
0
RD
1
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
251
Chapter 6 XGATE (S12XGATEV2)
CPC
CPC
Compare with Carry
Operation
RS2 – RS1 - C ⇒ NONE (translates to SBC R0, RS1, RS2)
Subtracts the carry bit and the content of register RS2 from the content of register RS1 using binary
subtraction and discards the result.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS1[15] & RS2[15] & result[15] | RS1[15] & RS2[15] & result[15]
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RS1[15] & RS2[15] | RS1[15] & result[15] | RS2[15] & result[15]
Code and CPU Cycles
Source Form
CPC RS1, RS2
Address
Mode
TRI
Machine Code
0
0
0
1
1
0
0
0
RS1
Cycles
RS2
0
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
252
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
CPCH
CPCH
Compare Immediate 8 bit Constant with
Carry (High Byte)
Operation
RS.H - IMM8 - C ⇒ NONE, only condition code flags get updated
Subtracts the carry bit and the 8 bit constant IMM8 contained in the instruction code from the high byte of
the source register RD using binary subtraction and updates the condition code register accordingly. The
carry bit and Zero bits are taken into account to allow a 16 bit compare in the form of
CMPL
CPCH
BCC
R2,#LOWBYTE
R2,#HIGHBYTE
; branch condition
Remark: There is no equivalent operation using triadic addressing. Comparing the values of two registers
can be performed by using the subtract instruction with R0 as destination register.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $00 and Z was set before this operation; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS[15] & IMM8[7] & result[15] | RS[15] & IMM8[7] & result[15]
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RS[15] & IMM8[7] | RS[15] & result[15] | IMM8[7] & result[15]
Code and CPU Cycles
Source Form
CPCH RD, #IMM8
Address
Mode
IMM8
Machine Code
1
1
0
1
1
RS
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
253
Chapter 6 XGATE (S12XGATEV2)
CSEM
CSEM
Clear Semaphore
Operation
Unlocks a semaphore that was locked by the RISC core.
In monadic address mode, bits RS[2:0] select the semaphore to be cleared.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
Address
Mode
Machine Code
Cycles
CSEM #IMM3
IMM3
0
0
0
0
0
IMM3
1
1
1
1
0
0
0
0
PA
CSEM RS
MON
0
0
0
0
0
RS
1
1
1
1
0
0
0
1
PA
MC9S12XDP512 Data Sheet, Rev. 2.21
254
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
CSL
CSL
Logical Shift Left with Carry
Operation
n
C
RD
C
C
C
C
n bits
n = RS or IMM4
Shifts the bits in register RD n positions to the left. The lower n bits of the register RD become filled with
the carry flag. The carry flag will be updated to the bit contained in RD[16-n] before the shift for n > 0.
n can range from 0 to 16.
In immediate address mode, n is determined by the operand IMM4. n is considered to be 16 in IMM4 is
equal to 0.
In dyadic address mode, n is determined by the content of RS. n is considered to be 16 if the content of RS
is greater than 15.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RD[15]old ^ RD[15]new
Set if n > 0 and RD[16-n] = 1; if n = 0 unaffected.
Code and CPU Cycles
Source Form
CSL RD, #IMM4
CSL RD, RS
Address
Mode
Machine Code
IMM4
0
0
0
0
1
RD
IMM4
DYA
0
0
0
0
1
RD
RS
Cycles
1
1
0
1
0
P
0
0
1
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
255
Chapter 6 XGATE (S12XGATEV2)
CSR
CSR
Logical Shift Right with Carry
Operation
n
C
C
C
C
RD
C
n bits
n = RS or IMM4
Shifts the bits in register RD n positions to the right. The higher n bits of the register RD become filled
with the carry flag. The carry flag will be updated to the bit contained in RD[n-1] before the shift for n > 0.
n can range from 0 to 16.
In immediate address mode, n is determined by the operand IMM4. n is considered to be 16 in IMM4 is
equal to 0.
In dyadic address mode, n is determined by the content of RS. n is considered to be 16 if the content of RS
is greater than 15.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RD[15]old ^ RD[15]new
Set if n > 0 and RD[n-1] = 1; if n = 0 unaffected.
Code and CPU Cycles
Source Form
CSR RD, #IMM4
CSR RD, RS
Address
Mode
Machine Code
IMM4
0
0
0
0
1
RD
IMM4
DYA
0
0
0
0
1
RD
RS
Cycles
1
1
0
1
1
P
0
0
1
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
256
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
JAL
JAL
Jump and Link
Operation
PC + $0002 ⇒ RD; RD ⇒ PC
Jumps to the address stored in RD and saves the return address in RD.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
JAL RD
Address
Mode
MON
Machine Code
0
0
0
0
0
RD
1
1
Cycles
1
1
0
1
1
0
PP
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
257
Chapter 6 XGATE (S12XGATEV2)
LDB
LDB
Load Byte from Memory
(Low Byte)
Operation
M[RB, #OFFS5 ⇒ RD.L; $00 ⇒ RD.H
M[RB, RI] ⇒ RD.L; $00 ⇒ RD.H
M[RB, RI] ⇒ RD.L; $00 ⇒ RD.H; RI+1 ⇒ RI;1
RI-1 ⇒ RI; M[RS, RI] ⇒ RD.L; $00 ⇒ RD.H
Loads a byte from memory into the low byte of register RD. The high byte is cleared.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
LDB RD, (RB, #OFFS5)
Address
Mode
Machine Code
Cycles
IDO5
0
1
0
0
0
RD
RB
OFFS5
Pr
LDB RD, (RS, RI)
IDR
0
1
1
0
0
RD
RB
RI
0
0
Pr
LDB RD, (RS, RI+)
IDR+
0
1
1
0
0
RD
RB
RI
0
1
Pr
LDB RD, (RS, -RI)
-IDR
0
1
1
0
0
RD
RB
RI
1
0
Pr
1.If the same general purpose register is used as index (RI) and destination register (RD), the content of the register will not
be incremented after the data move: M[RB, RI] ⇒ RD.L; $00 ⇒ RD.H
MC9S12XDP512 Data Sheet, Rev. 2.21
258
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
LDH
LDH
Load Immediate 8 bit Constant
(High Byte)
Operation
IMM8 ⇒ RD.H;
Loads an eight bit immediate constant into the high byte of register RD. The low byte is not affected.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
LDH RD, #IMM8
Address
Mode
IMM8
Machine Code
1
1
1
1
1
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
259
Chapter 6 XGATE (S12XGATEV2)
LDL
LDL
Load Immediate 8 bit Constant
(Low Byte)
Operation
IMM8 ⇒ RD.L; $00 ⇒ RD.H
Loads an eight bit immediate constant into the low byte of register RD. The high byte is cleared.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
LDL RD, #IMM8
Address
Mode
IMM8
Machine Code
1
1
1
1
0
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
260
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
LDW
LDW
Load Word from Memory
Operation
M[RB, #OFFS5] ⇒ RD
M[RB, RI] ⇒ RD
M[RB, RI] ⇒ RD; RI+2 ⇒ RI1
RI-2 ⇒ RI; M[RS, RI] ⇒ RD
IMM16 ⇒ RD (translates to LDL RD, #IMM16[7:0]; LDH RD, #IMM16[15:8])
Loads a 16 bit value into the register RD.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
LDW RD, (RB, #OFFS5)
Address
Mode
Machine Code
Cycles
IDO5
0
1
0
0
1
RD
RB
OFFS5
PR
LDW RD, (RB, RI)
IDR
0
1
1
0
1
RD
RB
RI
0
0
PR
LDW RD, (RB, RI+)
IDR+
0
1
1
0
1
RD
RB
RI
0
1
PR
LDW RD, (RB, -RI)
-IDR
0
1
1
0
1
RD
RB
RI
1
0
PR
LDW RD, #IMM16
IMM8
1
1
1
1
0
RD
IMM16[7:0]
P
IMM8
1
1
1
1
1
RD
IMM16[15:8]
P
1. If the same general purpose register is used as index (RI) and destination register (RD), the content of the register will not be
incremented after the data move: M[RB, RI] ⇒ RD
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
261
Chapter 6 XGATE (S12XGATEV2)
LSL
LSL
Logical Shift Left
Operation
n
C
RD
0
0
0
0
n bits
n = RS or IMM4
Shifts the bits in register RD n positions to the left. The lower n bits of the register RD become filled with
zeros. The carry flag will be updated to the bit contained in RD[16-n] before the shift for n > 0.
n can range from 0 to 16.
In immediate address mode, n is determined by the operand IMM4. n is considered to be 16 in IMM4 is
equal to 0.
In dyadic address mode, n is determined by the content of RS. n is considered to be 16 if the content of RS
is greater than 15.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RD[15]old ^ RD[15]new
Set if n > 0 and RD[16-n] = 1; if n = 0 unaffected.
Code and CPU Cycles
Source Form
LSL RD, #IMM4
LSL RD, RS
Address
Mode
Machine Code
IMM4
0
0
0
0
1
RD
IMM4
DYA
0
0
0
0
1
RD
RS
Cycles
1
1
1
0
0
P
0
1
0
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
262
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
LSR
LSR
Logical Shift Right
Operation
n
0
0
0
0
RD
C
n bits
n = RS or IMM4
Shifts the bits in register RD n positions to the right. The higher n bits of the register RD become filled
with zeros. The carry flag will be updated to the bit contained in RD[n-1] before the shift for n > 0.
n can range from 0 to 16.
In immediate address mode, n is determined by the operand IMM4. n is considered to be 16 in IMM4 is
equal to 0.
In dyadic address mode, n is determined by the content of RS. n is considered to be 16 if the content of RS
is greater than 15.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RD[15]old ^ RD[15]new
Set if n > 0 and RD[n-1] = 1; if n = 0 unaffected.
Code and CPU Cycles
Source Form
LSR RD, #IMM4
LSR RD, RS
Address
Mode
Machine Code
IMM4
0
0
0
0
1
RD
IMM4
DYA
0
0
0
0
1
RD
RS
Cycles
1
1
1
0
1
P
0
1
0
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
263
Chapter 6 XGATE (S12XGATEV2)
MOV
MOV
Move Register Content
Operation
RS ⇒ RD (translates to OR RD, R0, RS)
Copies the content of RS to RD.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
MOV RD, RS
Address
Mode
TRI
Machine Code
0
0
0
1
0
RD
0
0
Cycles
0
RS
1
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
264
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
NEG
NEG
Two’s Complement
Operation
–RS ⇒ RD (translates to SUB RD, R0, RS)
–RD ⇒ RD (translates to SUB RD, R0, RD)
Performs a two’s complement on a general purpose register.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS[15] & RD[15]new
Set if there is a carry from the bit 15 of the result; cleared otherwise
RS[15] | RD[15]new
Code and CPU Cycles
Source Form
Address
Mode
Machine Code
Cycles
NEG RD, RS
TRI
0 0 0 1 1
RD
0 0 0
RS
0 0
P
NEG RD
TRI
0 0 0 1 1
RD
0 0 0
RD
0 0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
265
Chapter 6 XGATE (S12XGATEV2)
NOP
NOP
No Operation
Operation
No Operation for one cycle.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
NOP
Address
Mode
INH
Machine Code
0
0
0
0
0
0
0
1
0
0
Cycles
0
0
0
0
0
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
266
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
OR
OR
Logical OR
Operation
RS1 | RS2 ⇒ RD
RD | IMM16⇒ RD (translates to ORL RD, #IMM16[7:0]; ORH RD, #IMM16[15:8]
Performs a bit wise logical OR between two 16 bit values and stores the result in the destination
register RD.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Refer to ORH instruction for #IMM16 operations.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
OR RD, RS1, RS2
OR RD, #IMM16
Address
Mode
Machine Code
RS1
Cycles
TRI
0
0
0
1
0
RD
RS2
1
0
P
IMM8
1
0
1
0
0
RD
IMM16[7:0]
P
IMM8
1
0
1
0
1
RD
IMM16[15:8]
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
267
Chapter 6 XGATE (S12XGATEV2)
ORH
ORH
Logical OR Immediate 8 bit Constant
(High Byte)
Operation
RD.H | IMM8 ⇒ RD.H
Performs a bit wise logical OR between the high byte of register RD and an immediate 8 bit constant and
stores the result in the destination register RD.H. The low byte of RD is not affected.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
ORH RD, #IMM8
Address
Mode
IMM8
Machine Code
1
0
1
0
1
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
268
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
ORL
ORL
Logical OR Immediate 8 bit Constant
(Low Byte)
Operation
RD.L | IMM8 ⇒ RD.L
Performs a bit wise logical OR between the low byte of register RD and an immediate 8 bit constant and
stores the result in the destination register RD.L. The high byte of RD is not affected.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 7 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
ORL RD, #IMM8
Address
Mode
IMM8
Machine Code
1
0
1
0
0
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
269
Chapter 6 XGATE (S12XGATEV2)
PAR
PAR
Calculate Parity
Operation
Calculates the number of ones in the register RD. The Carry flag will be set if the number is odd, otherwise
it will be cleared.
CCR Effects
N
Z
V
C
0
∆
0
∆
N:
Z:
V:
C:
0; cleared.
Set if RD is $0000; cleared otherwise.
0; cleared.
Set if there the number of ones in the register RD is odd; cleared otherwise.
Code and CPU Cycles
Source Form
PAR, RD
Address
Mode
MON
Machine Code
0
0
0
0
0
RD
1
1
Cycles
1
1
0
1
0
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
270
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
ROL
ROL
Rotate Left
Operation
RD
n bits
n = RS or IMM4
Rotates the bits in register RD n positions to the left. The lower n bits of the register RD are filled with the
upper n bits. Two source forms are available. In the first form, the parameter n is contained in the
instruction code as an immediate operand. In the second form, the parameter is contained in the lower bits
of the source register RS[3:0]. All other bits in RS are ignored. If n is zero, no shift will take place and the
register RD will be unaffected; however, the condition code flags will be updated.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
ROL RD, #IMM4
ROL RD, RS
Address
Mode
Machine Code
IMM4
0
0
0
0
1
RD
IMM4
DYA
0
0
0
0
1
RD
RS
Cycles
1
1
1
1
0
P
0
1
1
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
271
Chapter 6 XGATE (S12XGATEV2)
ROR
ROR
Rotate Right
Operation
RD
n bits
n = RS or IMM4
Rotates the bits in register RD n positions to the right. The upper n bits of the register RD are filled with
the lower n bits. Two source forms are available. In the first form, the parameter n is contained in the
instruction code as an immediate operand. In the second form, the parameter is contained in the lower bits
of the source register RS[3:0]. All other bits in RS are ignored. If n is zero no shift will take place and the
register RD will be unaffected; however, the condition code flags will be updated.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
ROR RD, #IMM4
ROR RD, RS
Address
Mode
Machine Code
IMM4
0
0
0
0
1
RD
IMM4
DYA
0
0
0
0
1
RD
RS
Cycles
1
1
1
1
1
P
0
1
1
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
272
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
RTS
RTS
Return to Scheduler
Operation
Terminates the current thread of program execution and remains idle until a new thread is started by the
hardware scheduler.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
RTS
Address
Mode
INH
Machine Code
0
0
0
0
0
0
1
0
0
0
Cycles
0
0
0
0
0
0
PA
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
273
Chapter 6 XGATE (S12XGATEV2)
SBC
SBC
Subtract with Carry
Operation
RS1 - RS2 - C ⇒ RD
Subtracts the content of register RS2 and the value of the Carry bit from the content of register RS1 using
binary subtraction and stores the result in the destination register RD. Also the zero flag is carried forward
from the previous operation allowing 32 and more bit subtractions.
Example:
SUB
SBC
BCC
R6,R4,R2
R7,R5,R3
; R7:R6 = R5:R4 - R3:R2
; conditional branch on 32 bit subtraction
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000 and Z was set before this operation; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS1[15] & RS2[15] & RD[15]new | RS1[15] & RS2[15] & RD[15]new
Set if there is a carry from bit 15 of the result; cleared otherwise.
RS1[15] & RS2[15] | RS1[15] & RD[15]new | RS2[15] & RD[15]new
Code and CPU Cycles
Source Form
SBC RD, RS1, RS2
Address
Mode
TRI
Machine Code
0
0
0
1
1
RD
RS1
Cycles
RS2
0
1
P
MC9S12XDP512 Data Sheet, Rev. 2.21
274
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
SEX
SEX
Sign Extend Byte to Word
Operation
The result in RD is the 16 bit sign extended representation of the original two’s complement number in the
low byte of RD.L.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
SEX RD
Address
Mode
MON
Machine Code
0
0
0
0
0
RD
1
1
Cycles
1
1
0
1
0
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
275
Chapter 6 XGATE (S12XGATEV2)
SIF
SIF
Set Interrupt Flag
Operation
Sets the Interrupt Flag of an XGATE Channel. This instruction supports two source forms. If inherent
address mode is used, then the interrupt flag of the current channel (XGCHID) will be set. If the monadic
address form is used, the interrupt flag associated with the channel id number contained in RS[6:0] is set.
The content of RS[15:7] is ignored.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
SIF
SIF RS
Address
Mode
Machine Code
INH
0
0
0
0
0
MON
0
0
0
0
0
0
1
1
RS
Cycles
0
0
0
0
0
0
0
0
PA
1
1
1
1
0
1
1
1
PA
MC9S12XDP512 Data Sheet, Rev. 2.21
276
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
SSEM
SSEM
Set Semaphore
Operation
Attempts to set a semaphore. The state of the semaphore will be stored in the Carry-Flag:
1 = Semaphore is locked by the RISC core
0 = Semaphore is locked by the S12X_CPU
In monadic address mode, bits RS[2:0] select the semaphore to be set.
CCR Effects
N
Z
V
C
—
—
—
∆
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Set if semaphore is locked by the RISC core; cleared otherwise.
Code and CPU Cycles
Source Form
Address
Mode
Machine Code
Cycles
SSEM #IMM3
IMM3
0
0
0
0
0
IMM3
1
1
1
1
0
0
1
0
PA
SSEM RS
MON
0
0
0
0
0
RS
1
1
1
1
0
0
1
1
PA
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
277
Chapter 6 XGATE (S12XGATEV2)
STB
STB
Store Byte to Memory
(Low Byte)
Operation
RS.L ⇒ M[RB, #OFFS5]
RS.L ⇒ M[RB, RI]
RS.L ⇒ M[RB, RI]; RI+1 ⇒ RI;
RI–1 ⇒ RI; RS.L ⇒ M[RB, RI]1
Stores the low byte of register RD to memory.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
STB RS, (RB, #OFFS5),
Address
Mode
Machine Code
Cycles
IDO5
0
1
0
1
0
RS
RB
OFFS5
Pw
STB RS, (RB, RI)
IDR
0
1
1
1
0
RS
RB
RI
0
0
Pw
STB RS, (RB, RI+)
IDR+
0
1
1
1
0
RS
RB
RI
0
1
Pw
STB RS, (RB, -RI)
-IDR
0
1
1
1
0
RS
RB
RI
1
0
Pw
1. If the same general purpose register is used as index (RI) and source register (RS), the unmodified content of the source
register is written to the memory: RS.L ⇒ M[RB, RS-1]; RS-1 ⇒ RS
MC9S12XDP512 Data Sheet, Rev. 2.21
278
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
STW
STW
Store Word to Memory
Operation
RS ⇒ M[RB, #OFFS5]
RS ⇒ M[RB, RI]
RS ⇒ M[RB, RI]; RI+2 ⇒ RI;
RI–2 ⇒ RI; RS ⇒ M[RB, RI]1
Stores the content of register RS to memory.
CCR Effects
N
Z
V
C
—
—
—
—
N:
Z:
V:
C:
Not affected.
Not affected.
Not affected.
Not affected.
Code and CPU Cycles
Source Form
STW RS, (RB, #OFFS5)
Address
Mode
Machine Code
Cycles
IDO5
0
1
0
1
1
RS
RB
OFFS5
PW
STW RS, (RB, RI)
IDR
0
1
1
1
1
RS
RB
RI
0
0
PW
STW RS, (RB, RI+)
IDR+
0
1
1
1
1
RS
RB
RI
0
1
PW
STW RS, (RB, -RI)
-IDR
0
1
1
1
1
RS
RB
RI
1
0
PW
1. If the same general purpose register is used as index (RI) and source register (RS), the unmodified content of the source
register is written to the memory: RS ⇒ M[RB, RS–2]; RS–2 ⇒ RS
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
279
Chapter 6 XGATE (S12XGATEV2)
SUB
SUB
Subtract without Carry
Operation
RS1 – RS2
⇒ RD
RD − IMM16 ⇒ RD (translates to SUBL RD, #IMM16[7:0]; SUBH RD, #IMM16{15:8])
Subtracts two 16 bit values and stores the result in the destination register RD.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS1[15] & RS2[15] & RD[15]new | RS1[15] & RS2[15] & RD[15]new
Refer to SUBH instruction for #IMM16 operations.
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RS1[15] & RS2[15] | RS1[15] & RD[15]new | RS2[15] & RD[15]new
Refer to SUBH instruction for #IMM16 operations.
Code and CPU Cycles
Source Form
SUB RD, RS1, RS2
SUB RD, #IMM16
Address
Mode
Machine Code
RS1
Cycles
TRI
0
0
0
1
1
RD
RS2
0
0
P
IMM8
1
1
0
0
0
RD
IMM16[7:0]
P
IMM8
1
1
0
0
1
RD
IMM16[15:8]
P
MC9S12XDP512 Data Sheet, Rev. 2.21
280
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
SUBH
SUBH
Subtract Immediate 8 bit Constant
(High Byte)
Operation
RD – IMM8:$00 ⇒ RD
Subtracts a signed immediate 8 bit constant from the content of high byte of register RD and using binary
subtraction and stores the result in the high byte of destination register RD. This instruction can be used
after an SUBL for a 16 bit immediate subtraction.
Example:
SUBL
SUBH
R2,#LOWBYTE
R2,#HIGHBYTE
; R2 = R2 - 16 bit immediate
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RD[15]old & IMM8[7] & RD[15]new | RD[15]old & IMM8[7] & RD[15]new
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RD[15]old & IMM8[7] | RD[15]old & RD[15]new | IMM8[7] & RD[15]new
Code and CPU Cycles
Source Form
SUBH RD, #IMM8
Address
Mode
IMM8
Machine Code
1
1
0
0
1
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
281
Chapter 6 XGATE (S12XGATEV2)
SUBL
Subtract Immediate 8 bit Constant
(Low Byte)
SUBL
Operation
RD – $00:IMM8 ⇒ RD
Subtracts an immediate 8 bit constant from the content of register RD using binary subtraction and stores
the result in the destination register RD.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the 8 bit operation; cleared otherwise.
RD[15]old & RD[15]new
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RD[15]old & RD[15]new
Code and CPU Cycles
Source Form
SUBL RD, #IMM8
Address
Mode
IMM8
Machine Code
1
1
0
0
0
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
282
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
TFR
TFR
Transfer from and to Special Registers
Operation
TFR RD,CCR: CCR ⇒ RD[3:0]; 0 ⇒ RD[15:4]
TFR CCR,RD: RD[3:0] ⇒ CCR
TFR RD,PC:
PC+4 ⇒ RD
Transfers the content of one RISC core register to another.
The TFR RD,PC instruction can be used to implement relative subroutine calls.
Example:
RETADDR
SUBR
TFR
BRA
...
...
JAL
R7,PC
SUBR
;Return address (RETADDR) is stored in R7
;Relative branch to subroutine (SUBR)
R7
;Jump to return address (RETADDR)
CCR Effects
TFR RD,CCR, TFR RD,PC:
TFR CCR,RS:
N
Z
V
C
N
Z
V
C
—
—
—
—
∆
∆
∆
∆
Not affected.
Not affected.
Not affected.
Not affected.
N:
Z:
V:
C:
N:
Z:
V:
C:
RS[3].
RS[2].
RS[1].
RS[0].
Code and CPU Cycles
Source Form
Address
Mode
Machine Code
Cycles
TFR RD,CCR CCR ⇒ RD
MON
0
0
0
0
0
RD
1
1
1
1
1
0
0
0
P
TFR CCR,RS RS ⇒ CCR
MON
0
0
0
0
0
RS
1
1
1
1
1
0
0
1
P
TFR RD,PCPC+4 ⇒ RD
MON
0
0
0
0
0
RD
1
1
1
1
1
0
1
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
283
Chapter 6 XGATE (S12XGATEV2)
TST
TST
Test Register
Operation
RS – 0 ⇒ NONE (translates to SUB R0, RS, R0)
Subtracts zero from the content of register RS using binary subtraction and discards the result.
CCR Effects
N
Z
V
C
∆
∆
∆
∆
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Set if a two´s complement overflow resulted from the operation; cleared otherwise.
RS[15] & result[15]
Set if there is a carry from the bit 15 of the result; cleared otherwise.
RS1[15] & result[15]
Code and CPU Cycles
Source Form
TST RS
Address
Mode
TRI
Machine Code
0
0
0
1
1
0
0
0
RS1
Cycles
0
0
0
0
0
P
MC9S12XDP512 Data Sheet, Rev. 2.21
284
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
XNOR
XNOR
Logical Exclusive NOR
Operation
~(RS1 ^ RS2) ⇒ RD
~(RD ^ IMM16)⇒ RD
(translates to XNOR RD, #IMM16{15:8]; XNOR RD, #IMM16[7:0])
Performs a bit wise logical exclusive NOR between two 16 bit values and stores the result in the destination
register RD.
Remark: Using R0 as a source registers will calculate the one’s complement of the other source register.
Using R0 as both source operands will fill RD with $FFFF.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the result is $0000; cleared otherwise.
Refer to XNORH instruction for #IMM16 operations.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
XNOR RD, RS1, RS2
XNOR RD, #IMM16
Address
Mode
Machine Code
RS1
Cycles
TRI
0
0
0
1
0
RD
RS2
1
1
P
IMM8
1
0
1
1
0
RD
IMM16[7:0]
P
IMM8
1
0
1
1
1
RD
IMM16[15:8]
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
285
Chapter 6 XGATE (S12XGATEV2)
XNORH
Logical Exclusive NOR Immediate
8 bit Constant (High Byte)
XNORH
Operation
~(RD.H ^ IMM8) ⇒ RD.H
Performs a bit wise logical exclusive NOR between the high byte of register RD and an immediate 8 bit
constant and stores the result in the destination register RD.H. The low byte of RD is not affected.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 15 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
XNORH RD, #IMM8
Address
Mode
IMM8
Machine Code
1
0
1
1
1
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
286
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
XNORL
Logical Exclusive NOR Immediate
8 bit Constant (Low Byte)
XNORL
Operation
~(RD.L ^ IMM8) ⇒ RD.L
Performs a bit wise logical exclusive NOR between the low byte of register RD and an immediate 8 bit
constant and stores the result in the destination register RD.L. The high byte of RD is not affected.
CCR Effects
N
Z
V
C
∆
∆
0
—
N:
Z:
V:
C:
Set if bit 7 of the result is set; cleared otherwise.
Set if the 8 bit result is $00; cleared otherwise.
0; cleared.
Not affected.
Code and CPU Cycles
Source Form
XNORL RD, #IMM8
Address
Mode
IMM8
Machine Code
1
0
1
1
0
RD
Cycles
IMM8
P
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
287
Chapter 6 XGATE (S12XGATEV2)
6.8.6
Instruction Coding
Table 6-17 summarizes all XGATE instructions in the order of their machine coding.
Table 6-17. Instruction Set Summary (Sheet 1 of 3)
Functionality
Return to Scheduler and Others
BRK
NOP
RTS
SIF
Semaphore Instructions
CSEM IMM3
CSEM RS
SSEM IMM3
SSEM RS
Single Register Instructions
SEX RD
PAR RD
JAL RD
SIF RS
Special Move instructions
TFR RD,CCR
TFR CCR,RS
TFR RD,PC
Shift instructions Dyadic
BFFO RD, RS
ASR RD, RS
CSL RD, RS
CSR RD, RS
LSL RD, RS
LSR RD, RS
ROL RD, RS
ROR RD, RS
Shift instructions immediate
ASR RD, #IMM4
CSL RD, #IMM4
CSR RD, #IMM4
LSL RD, #IMM4
LSR RD, #IMM4
ROL RD, #IMM4
ROR RD, #IMM4
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
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
1
1
0
1
0
1
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
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
IMM3
RS
IMM3
RS
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RD
RD
RD
RS
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RD
RS
RD
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
1
0
1
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
1
1
1
1
1
1
1
1
RD
RD
RD
RD
RD
RD
RD
RD
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
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
1
1
1
1
1
1
1
RD
RD
RD
RD
RD
RD
RD
1
1
1
1
1
1
1
0
0
0
1
1
1
1
0
1
1
0
0
1
1
1
0
1
0
1
0
1
RS
RS
RS
RS
RS
RS
RS
RS
IMM4
IMM4
IMM4
IMM4
IMM4
IMM4
IMM4
MC9S12XDP512 Data Sheet, Rev. 2.21
288
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
Table 6-17. Instruction Set Summary (Sheet 2 of 3)
Functionality
Logical Triadic
AND RD, RS1, RS2
OR RD, RS1, RS2
XNOR RD, RS1, RS2
Arithmetic Triadic
SUB RD, RS1, RS2
SBC RD, RS1, RS2
ADD RD, RS1, RS2
ADC RD, RS1, RS2
Branches
BCC REL9
BCS REL9
BNE REL9
BEQ REL9
BPL REL9
BMI REL9
BVC REL9
BVS REL9
BHI REL9
BLS REL9
BGE REL9
BLT REL9
BGT REL9
BLE REL9
BRA REL10
Load and Store Instructions
LDB RD, (RB, #OFFS5)
LDW RD, (RB, #OFFS5)
STB RS, (RB, #OFFS5)
STW RS, (RB, #OFFS5)
LDB RD, (RB, RI)
LDW RD, (RB, RI)
STB RS, (RB, RI)
STW RS, (RB, RI)
LDB RD, (RB, RI+)
LDW RD, (RB, RI+)
STB RS, (RB, RI+)
STW RS, (RB, RI+)
LDB RD, (RB, –RI)
LDW RD, (RB, –RI)
STB RS, (RB, –RI)
STW RS, (RB, –RI)
Bit Field Instructions
BFEXT RD, RS1, RS2
BFINS RD, RS1, RS2
BFINSI RD, RS1, RS2
BFINSX RD, RS1, RS2
Logic Immediate Instructions
ANDL RD, #IMM8
15
14
13
12
11
10
9
8
7
6
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
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
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
RD
RD
RS
RS
RD
RD
RS
RS
RD
RD
RS
RS
RD
RD
RS
RS
RB
RB
RB
RB
RB
RB
RB
RB
RB
RB
RB
RB
RB
RB
RB
RB
0
0
0
0
1
1
1
1
1
1
1
1
0
0
1
1
0
1
0
1
RD
RD
RD
RD
RS1
RS1
RS1
RS1
1
0
0
0
0
RD
5
4
3
2
1
0
0
1
1
0
0
1
0
0
1
1
0
1
0
1
RI
RI
RI
RI
RI
RI
RI
RI
RI
RI
RI
RI
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
RS2
RS2
RS2
RS2
1
1
1
1
1
1
1
1
RD
RS1
RS2
RD
RS1
RS2
RD
RS1
RS2
For compare use SUB R0,Rs1,Rs2
RD
RS1
RS2
RD
RS1
RS2
RD
RS1
RS2
RD
RS1
RS2
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
REL9
REL9
REL9
REL9
REL9
REL9
REL9
REL9
REL9
REL9
REL9
REL9
REL9
REL9
REL10
OFFS5
OFFS5
OFFS5
OFFS5
IMM8
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
289
Chapter 6 XGATE (S12XGATEV2)
Table 6-17. Instruction Set Summary (Sheet 3 of 3)
Functionality
ANDH RD, #IMM8
BITL RD, #IMM8
BITH RD, #IMM8
ORL RD, #IMM8
ORH RD, #IMM8
XNORL RD, #IMM8
XNORH RD, #IMM8
Arithmetic Immediate Instructions
SUBL RD, #IMM8
SUBH RD, #IMM8
CMPL RS, #IMM8
CPCH RS, #IMM8
ADDL RD, #IMM8
ADDH RD, #IMM8
LDL RD, #IMM8
LDH RD, #IMM8
15
14
13
12
11
10
9
8
7
6
5
4
3
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
1
1
0
0
1
1
1
0
1
0
1
0
1
RD
RD
RD
RD
RD
RD
RD
IMM8
IMM8
IMM8
IMM8
IMM8
IMM8
IMM8
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
RD
RD
RS
RS
RD
RD
RD
RD
IMM8
IMM8
IMM8
IMM8
IMM8
IMM8
IMM8
IMM8
2
1
0
MC9S12XDP512 Data Sheet, Rev. 2.21
290
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
6.9
Initialization and Application Information
6.9.1
Initialization
The recommended initialization of the XGATE is as follows:
1. Clear the XGE bit to suppress any incoming service requests.
2. Make sure that no thread is running on the XGATE. This can be done in several ways:
a) Poll the XGCHID register until it reads $00. Also poll XGDBG and XGSWEIF to make sure
that the XGATE has not been stopped.
b) Enter Debug Mode by setting the XGDBG bit. Clear the XGCHID register. Clear the XGDBG
bit.
The recommended method is a).
3. Set the XGVBR register to the lowest address of the XGATE vector space.
4. Clear all Channel ID flags.
5. Copy XGATE vectors and code into the RAM.
6. Initialize the S12X_INT module.
7. Enable the XGATE by setting the XGE bit.
The following code example implements the XGATE initialization sequence.
6.9.2
Code Example (Transmit "Hello World!" on SCI)
SCI_REGS
SCIBDH
SCIBDL
SCICR2
SCISR1
SCIDRL
TIE
TE
RE
SCI_VEC
CPU S12X
;###########################################
;#
SYMBOLS
#
;###########################################
EQU $00C8
;SCI register space
EQU SCI_REGS+$00
;SCI Baud Rate Register
EQU SCI_REGS+$00
;SCI Baud Rate Register
EQU SCI_REGS+$03
;SCI Control Register 2
EQU SCI_REGS+$04
;SCI Status Register 1
EQU SCI_REGS+$07
;SCI Control Register 2
EQU $80
;TIE bit mask
EQU $08
;TE bit mask
EQU $04
;RE bit mask
EQU $D6
;SCI vector number
INT_REGS
INT_CFADDR
INT_CFDATA
RQST
EQU
EQU
EQU
EQU
INT_REGS+$07
INT_REGS+$08
$80
$0120
;S12X_INT register space
;Interrupt Configuration Address Register
;Interrupt Configuration Data Registers
;RQST bit mask
XGATE_REGS
XGMCTL
XGMCTL_CLEAR
XGMCTL_ENABLE
XGCHID
XGVBR
XGIF
EQU
EQU
EQU
EQU
EQU
EQU
EQU
$0380
XGATE_REGS+$00
$FA02
$8282
XGATE_REGS+$02
XGATE_REGS+$06
XGATE_REGS+$08
;XGATE register space
;XGATE Module Control Register
;Clear all XGMCTL bits
;Enable XGATE
;XGATE Channel ID Register
;XGATE ISP Select Register
;XGATE Interrupt Flag Vector
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
291
Chapter 6 XGATE (S12XGATEV2)
XGSWT
XGSEM
EQU
EQU
XGATE_REGS+$18
XGATE_REGS+$1A
;XGATE Software Trigger Register
;XGATE Semaphore Register
RPAGE
EQU
$0016
RAM_SIZE
EQU
32*$400
RAM_START
RAM_START_XG
RAM_START_GLOB
EQU
EQU
EQU
$1000
$10000-RAM_SIZE
$100000-RAM_SIZE
XGATE_VECTORS
XGATE_VECTORS_XG
EQU
EQU
RAM_START
RAM_START_XG
XGATE_DATA
XGATE_DATA_XG
EQU
EQU
RAM_START+(4*128)
RAM_START_XG+(4*128)
XGATE_CODE
XGATE_CODE_XG
EQU
EQU
XGATE_DATA+(XGATE_CODE_FLASH-XGATE_DATA_FLASH)
XGATE_DATA_XG+(XGATE_CODE_FLASH-XGATE_DATA_FLASH)
BUS_FREQ_HZ
EQU
40000000
;32k RAM
;###########################################
;#
S12XE VECTOR TABLE
#
;###########################################
ORG $FF10 ;non-maskable interrupts
DW
DUMMY_ISR DUMMY_ISR DUMMY_ISR DUMMY_ISR
ORG
DW
$FFF4 ;non-maskable interrupts
DUMMY_ISR DUMMY_ISR DUMMY_ISR
;###########################################
;#
DISABLE COP
#
;###########################################
ORG $FF0E
DW
$FFFE
ORG
$C000
START_OF_CODE
;###########################################
;#
INITIALIZE S12XE CORE
#
;###########################################
SEI
MOVB #(RAM_START_GLOB>>12), RPAGE;set RAM page
INIT_SCI
INIT_INT
;###########################################
;#
INITIALIZE SCI
#
;###########################################
MOVW #(BUS_FREQ_HZ/(16*9600)), SCIBDH;set baud rate
MOVB #(TIE|TE), SCICR2;enable tx buffer empty interrupt
;###########################################
;#
INITIALIZE S12X_INT
#
;###########################################
MOVB #(SCI_VEC&$F0), INT_CFADDR ;switch SCI interrupts to XGATE
MOVB #RQST|$01, INT_CFDATA+((SCI_VEC&$0F)>>1)
MC9S12XDP512 Data Sheet, Rev. 2.21
292
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
INIT_XGATE
INIT_XGATE_BUSY_LOOP
;###########################################
;#
INITIALIZE XGATE
#
;###########################################
MOVW #XGMCTL_CLEAR , XGMCTL;clear all XGMCTL bits
TST
BNE
XGCHID
;wait until current thread is finished
INIT_XGATE_BUSY_LOOP
LDX
LDD
STD
STD
STD
STD
STD
STD
STD
STD
#XGIF
#$FFFF
2,X+
2,X+
2,X+
2,X+
2,X+
2,X+
2,X+
2,X+
;clear all channel interrupt flags
MOVW #XGATE_VECTORS_XG, XGVBR;set vector base register
MOVW #$FF00, XGSWT
INIT_XGATE_VECTAB_LOOP
;clear all software triggers
;###########################################
;#
INITIALIZE XGATE VECTOR TABLE
#
;###########################################
LDAA #128
;build XGATE vector table
LDY #XGATE_VECTORS
MOVW #XGATE_DUMMY_ISR_XG, 4,Y+
DBNE A, INIT_XGATE_VECTAB_LOOP
MOVW #XGATE_CODE_XG, RAM_START+(2*SCI_VEC)
MOVW #XGATE_DATA_XG, RAM_START+(2*SCI_VEC)+2
COPY_XGATE_CODE
COPY_XGATE_CODE_LOOP
START_XGATE
DUMMY_ISR
;###########################################
;#
COPY XGATE CODE
#
;###########################################
LDX #XGATE_DATA_FLASH
MOVW 2,X+, 2,Y+
MOVW 2,X+, 2,Y+
MOVW 2,X+, 2,Y+
MOVW 2,X+, 2,Y+
CPX #XGATE_CODE_FLASH_END
BLS COPY_XGATE_CODE_LOOP
;###########################################
;#
START XGATE
#
;###########################################
MOVW #XGMCTL_ENABLE, XGMCTL;enable XGATE
BRA *
;###########################################
;#
DUMMY INTERRUPT SERVICE ROUTINE
#
;###########################################
RTI
CPU
XGATE
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
293
Chapter 6 XGATE (S12XGATEV2)
XGATE_DATA_FLASH
XGATE_DATA_SCI
XGATE_DATA_IDX
XGATE_DATA_MSG
XGATE_CODE_FLASH
XGATE_CODE_DONE
XGATE_CODE_FLASH_END
XGATE_DUMMY_ISR_XG
;###########################################
;#
XGATE DATA
#
;###########################################
ALIGN 1
EQU *
EQU *-XGATE_DATA_FLASH
DW
SCI_REGS
;pointer to SCI register space
EQU *-XGATE_DATA_FLASH
DB
XGATE_DATA_MSG ;string pointer
EQU *-XGATE_DATA_FLASH
FCC "Hello World!
;ASCII string
DB
$0D
;CR
;###########################################
;#
XGATE CODE
#
;###########################################
ALIGN 1
LDW R2,(R1,#XGATE_DATA_SCI);SCI -> R2
LDB R3,(R1,#XGATE_DATA_IDX);msg -> R3
LDB R4,(R1,R3+)
;curr. char -> R4
STB R3,(R1,#XGATE_DATA_IDX);R3 -> idx
LDB R0,(R2,#(SCISR1-SCI_REGS));initiate SCI transmit
STB R4,(R2,#(SCIDRL-SCI_REGS));initiate SCI transmit
CMPL R4,#$0D
BEQ XGATE_CODE_DONE
RTS
LDL R4,#$00
;disable SCI interrupts
STB R4,(R2,#(SCICR2-SCI_REGS))
LDL R3,#XGATE_DATA_MSG;reset R3
STB R3,(R1,#XGATE_DATA_IDX)
RTS
EQU (XGATE_CODE_FLASH_END-XGATE_CODE_FLASH)+XGATE_CODE_XG
MC9S12XDP512 Data Sheet, Rev. 2.21
294
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
295
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
296
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
297
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
298
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
299
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
300
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
301
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
302
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
303
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
304
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
305
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
306
Freescale Semiconductor
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
307
Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
308
Freescale Semiconductor
Chapter 7
Enhanced Capture Timer (S12ECT16B8CV2)
7.1
Introduction
The HCS12 enhanced capture timer module has the features of the HCS12 standard timer module
enhanced by additional features in order to enlarge the field of applications, in particular for automotive
ABS applications.
This design specification describes the standard timer as well as the additional features.
The basic timer consists of a 16-bit, software-programmable counter driven by a 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.
A full access for the counter registers or the input capture/output compare registers will take place in one
clock cycle. Accessing high byte and low byte separately for all of these registers will not yield the same
result as accessing them in one word.
7.1.1
•
•
•
•
7.1.2
•
•
•
•
Features
16-bit buffer register for four input capture (IC) channels.
Four 8-bit pulse accumulators with 8-bit buffer registers associated with the four buffered IC
channels. Configurable also as two 16-bit pulse accumulators.
16-bit modulus down-counter with 8-bit prescaler.
Four user-selectable delay counters for input noise immunity increase.
Modes of Operation
Stop — Timer and modulus counter are off since clocks are stopped.
Freeze — Timer and modulus counter keep on running, unless the TSFRZ bit in the TSCR1 register
is set to one.
Wait — Counters keep on running, unless the TSWAI bit in the TSCR1 register is set to one.
Normal — Timer and modulus counter keep on running, unless the TEN bit in the TSCR1 register
or the MCEN bit in the MCCTL register are cleared.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
309
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.1.3
Block Diagram
Bus Clock
Prescaler
Channel 0
Input Capture
16-bit Counter
Output Compare
Channel 1
Input Capture
Modulus Counter
Interrupt
16-Bit Modulus Counter
Output Compare
IOC0
IOC1
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
PB Overflow
Interrupt
16-Bit
Pulse Accumulator A
16-Bit
Pulse Accumulator B
Channel 6
Input Capture
Output Compare
Channel 7
Input Capture
IOC2
IOC3
IOC4
IOC5
IOC6
IOC7
Output Compare
Figure 7-1. ECT Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
310
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.2
External Signal Description
The ECT module has a total of eight external pins.
7.2.1
IOC7 — Input Capture and Output Compare Channel 7
This pin serves as input capture or output compare for channel 7.
7.2.2
IOC6 — Input Capture and Output Compare Channel 6
This pin serves as input capture or output compare for channel 6.
7.2.3
IOC5 — Input Capture and Output Compare Channel 5
This pin serves as input capture or output compare for channel 5.
7.2.4
IOC4 — Input Capture and Output Compare Channel 4
This pin serves as input capture or output compare for channel 4.
7.2.5
IOC3 — Input Capture and Output Compare Channel 3
This pin serves as input capture or output compare for channel 3.
7.2.6
IOC2 — Input Capture and Output Compare Channel 2
This pin serves as input capture or output compare for channel 2.
7.2.7
IOC1 — Input Capture and Output Compare Channel 1
This pin serves as input capture or output compare for channel 1.
7.2.8
IOC0 — Input Capture and Output Compare Channel 0
This pin serves as input capture or output compare for channel 0.
NOTE
For the description of interrupts see Section 7.4.3, “Interrupts”.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
311
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3
Memory Map and Register Definition
This section provides a detailed description of all memory and registers.
7.3.1
Module Memory Map
The memory map for the ECT module is given below in Table 7-1. 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 ECT module
and the address offset for each register.
Table 7-1. ECT Memory Map
Address
Offset
Register
Access
0x0000
Timer Input Capture/Output Compare Select (TIOS)
R/W
0x0001
Timer Compare Force Register (CFORC)
R/W1
0x0002
Output Compare 7 Mask Register (OC7M)
R/W
0x0003
Output Compare 7 Data Register (OC7D)
R/W
0x0004
Timer Count Register High (TCNT)
R/W2
0x0005
Timer Count Register Low (TCNT)
R/W2
0x0006
Timer System Control Register 1 (TSCR1)
R/W
0x0007
Timer Toggle Overflow Register (TTOV)
R/W
0x0008
Timer Control Register 1 (TCTL1)
R/W
0x0009
Timer Control Register 2 (TCTL2)
R/W
0x000A
Timer Control Register 3 (TCTL3)
R/W
0x000B
Timer Control Register 4 (TCTL4)
R/W
0x000C
Timer Interrupt Enable Register (TIE)
R/W
0x000D
Timer System Control Register 2 (TSCR2)
R/W
0x000E
Main Timer Interrupt Flag 1 (TFLG1)
R/W
0x000F
Main Timer Interrupt Flag 2 (TFLG2)
R/W
0x0010
Timer Input Capture/Output Compare Register 0 High (TC0)
R/W3
0x0011
Timer Input Capture/Output Compare Register 0 Low (TC0)
R/W3
0x0012
Timer Input Capture/Output Compare Register 1 High (TC1)
R/W3
0x0013
Timer Input Capture/Output Compare Register 1 Low (TC1)
R/W3
0x0014
Timer Input Capture/Output Compare Register 2 High (TC2)
R/W3
0x0015
Timer Input Capture/Output Compare Register 2 Low (TC2)
R/W3
0x0016
Timer Input Capture/Output Compare Register 3 High (TC3)
R/W3
0x0017
Timer Input Capture/Output Compare Register 3 Low (TC3)
R/W3
0x0018
Timer Input Capture/Output Compare Register 4 High (TC4)
R/W3
0x0019
Timer Input Capture/Output Compare Register 4 Low (TC4)
R/W3
0x001A
Timer Input Capture/Output Compare Register 5 High (TC5)
R/W3
0x001B
Timer Input Capture/Output Compare Register 5 Low (TC5)
R/W3
0x001C
Timer Input Capture/Output Compare Register 6 High (TC6)
R/W3
0x001D
Timer Input Capture/Output Compare Register 6 Low (TC6)
R/W3
MC9S12XDP512 Data Sheet, Rev. 2.21
312
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Table 7-1. ECT Memory Map (continued)
Address
Offset
Register
Access
0x001E
Timer Input Capture/Output Compare Register 7 High (TC7)
R/W3
0x001F
Timer Input Capture/Output Compare Register 7 Low (TC7)
R/W3
0x0020
16-Bit Pulse Accumulator A Control Register (PACTL)
R/W
0x0021
Pulse Accumulator A Flag Register (PAFLG)
R/W
0x0022
Pulse Accumulator Count Register 3 (PACN3)
R/W
0x0023
Pulse Accumulator Count Register 2 (PACN2)
R/W
0x0024
Pulse Accumulator Count Register 1 (PACN1)
R/W
0x0025
Pulse Accumulator Count Register 0 (PACN0)
R/W
0x0026
16-Bit Modulus Down Counter Register (MCCTL)
R/W
0x0027
16-Bit Modulus Down Counter Flag Register (MCFLG)
R/W
0x0028
Input Control Pulse Accumulator Register (ICPAR)
R/W
0x0029
Delay Counter Control Register (DLYCT)
R/W
0x002A
Input Control Overwrite Register (ICOVW)
R/W
0x002B
Input Control System Control Register (ICSYS)
R/W4
0x002C
Reserved
0x002D
Timer Test Register (TIMTST)
R/W2
0x002E
Precision Timer Prescaler Select Register (PTPSR)
R/W
0x002F
Precision Timer Modulus Counter Prescaler Select Register (PTMCPSR)
R/W
0x0030
16-Bit Pulse Accumulator B Control Register (PBCTL)
R/W
0x0031
16-Bit Pulse Accumulator B Flag Register (PBFLG)
R/W
0x0032
8-Bit Pulse Accumulator Holding Register 3 (PA3H)
R/W5
0x0033
8-Bit Pulse Accumulator Holding Register 2 (PA2H)
R/W5
0x0034
8-Bit Pulse Accumulator Holding Register 1 (PA1H)
R/W5
0x0035
8-Bit Pulse Accumulator Holding Register 0 (PA0H)
R/W5
0x0036
Modulus Down-Counter Count Register High (MCCNT)
R/W
0x0037
Modulus Down-Counter Count Register Low (MCCNT)
R/W
0x0038
Timer Input Capture Holding Register 0 High (TC0H)
R/W5
0x0039
Timer Input Capture Holding Register 0 Low (TC0H)
R/W5
0x003A
Timer Input Capture Holding Register 1 High(TC1H)
R/W5
0x003B
Timer Input Capture Holding Register 1 Low (TC1H)
R/W5
0x003C
Timer Input Capture Holding Register 2 High (TC2H)
R/W5
0x003D
Timer Input Capture Holding Register 2 Low (TC2H)
R/W5
0x003E
Timer Input Capture Holding Register 3 High (TC3H)
R/W5
0x003F
Timer Input Capture Holding Register 3 Low (TC3H)
R/W5
--
1
Always read 0x0000.
Only writable in special modes (test_mode = 1).
3 Writes to these registers have no meaning or effect during input capture.
4 May be written once when not in test00mode but writes are always permitted when test00mode is enabled.
5 Writes have no effect.
2
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
313
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2
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
TIOS
Bit 7
6
5
4
3
2
1
Bit 0
IOS7
IOS6
IOS5
IOS4
IOS3
IOS2
IOS1
IOS0
R
0
0
0
0
0
0
0
0
W
FOC7
FOC6
FOC5
FOC4
FOC3
FOC2
FOC1
FOC0
OC7M7
OC7M6
OC7M5
OC7M4
OC7M3
OC7M2
OC7M1
OC7M0
OC7D7
OC7D6
OC7D5
OC7D4
OC7D3
OC7D2
OC7D1
OC7D0
TCNT15
TCNT14
TCNT13
TCNT12
TCNT11
TCNT10
TCNT9
TCNT8
TCNT7
TCNT6
TCNT5
TCNT4
TCNT3
TCNT2
TCNT1
TCNT0
TEN
TSWAI
TSFRZ
TFFCA
PRNT
0
0
0
TOV7
TOV6
TOV5
TOV4
TOV3
TOV2
TOV1
TOV0
OM7
OL7
OM6
OL6
OM5
OL5
OM4
OL4
OM3
OL3
OM2
OL2
OM1
OL1
OM0
OL0
EDG7B
EDG7A
EDG6B
EDG6A
EDG5B
EDG5A
EDG4B
EDG4A
EDG3B
EDG3A
EDG2B
EDG2A
EDG1B
EDG1A
EDG0B
EDG0A
C7I
C6I
C5I
C4I
C3I
C2I
C1I
C0I
R
W
CFORC
OC7M
R
W
OC7D
R
W
TCNT (High) R
W
TCNT (Low) R
W
TSCR1
R
W
TTOF
R
W
TCTL1
R
W
TCTL2
R
W
TCTL3
R
W
TCTL4
R
W
TIE
R
W
= Unimplemented or Reserved
Figure 7-2. ECT Register Summary (Sheet 1 of 5)
MC9S12XDP512 Data Sheet, Rev. 2.21
314
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Register
Name
TSCR2
Bit 7
R
W
TFLG1
R
W
TFLG2
R
W
TC0 (High)
R
W
TC0 (Low)
R
W
TC1 (High)
R
W
TC1 (Low)
R
W
TC2 (High)
R
W
TC2 (Low)
R
W
TC3 (High)
R
W
TC3 (Low)
R
W
TC4 (High)
R
W
TC4 (Low)
R
W
TC5 (High)
R
W
TC5 (Low)
R
W
6
5
4
3
2
1
Bit 0
0
0
0
TCRE
PR2
PR1
PR0
C6F
C5F
C4F
C3F
C2F
C1F
C0F
0
0
0
0
0
0
0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
TOI
C7F
TOF
= Unimplemented or Reserved
Figure 7-2. ECT Register Summary (Sheet 2 of 5)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
315
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Register
Name
TC6 (High)
R
W
TC6 (Low)
R
W
TC7 (High)
R
W
TC7 (Low)
R
W
PACTL
R
Bit 7
6
5
4
3
2
1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PAEN
PAMOD
PEDGE
CLK1
CLK0
PA0VI
PAI
0
0
0
0
0
PA0VF
PAIF
0
W
PAFLG
R
0
W
PACN3
R
W
PACN2
R
W
PACN1
R
W
PACN0
R
W
MCCTL
R
W
MCFLG
R
W
ICPAR
R
PACNT7(15) PACNT6(14) PACNT5(13) PACNT4(12) PACNT3(11) PACNT2(10) PACNT1(9) PACNT0(8)
PACNT7
PACNT6
PACNT5
PACNT4
R
W
ICOVW
R
W
PACNT2
PACNT1
PACNT0
PACNT7(15) PACNT6(14) PACNT5(13) PACNT4(12) PACNT3(11) PACNT2(10) PACNT1(9) PACNT0(8)
PACNT7
PACNT6
PACNT5
PACNT4
PACNT3
MCZI
MODMC
RDMCL
0
0
ICLAT
FLMC
0
0
0
0
0
0
0
DLY7
DLY6
DLY5
NOVW7
NOVW6
NOVW5
MCZF
PACNT2
PACNT1
PACNT0
MCEN
MCPR1
MCPR0
POLF3
POLF2
POLF1
POLF0
PA3EN
PA2EN
PA1EN
PA0EN
DLY4
DLY3
DLY2
DLY1
DLY0
NOVW4
NOVW3
NOVW2
NOVW1
NOVW0
W
DLYCT
PACNT3
= Unimplemented or Reserved
Figure 7-2. ECT Register Summary (Sheet 3 of 5)
MC9S12XDP512 Data Sheet, Rev. 2.21
316
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Register
Name
ICSYS
R
W
Reserved
Bit 7
6
5
4
3
2
1
Bit 0
SH37
SH26
SH15
SH04
TFMOD
PACMX
BUFEN
LATQ
R
Reserved
W
TIMTST
R
Timer Test Register
W
PTPSR
R
W
PTMCPSR
R
W
PBCTL
R
PTPS7
PTPS6
PTPS5
PTPS4
PTPS3
PTPS2
PTPS1
PTPS0
PTMPS7
PTMPS6
PTMPS5
PTMPS4
PTMPS3
PTMPS2
PTMPS1
PTMPS0
0
0
0
0
0
W
PBFLG
R
PBEN
R
0
0
0
0
0
0
0
PA3H7
PA3H6
PA3H5
PA3H4
PA3H3
PA3H2
PA3H1
PA3H0
PA2H7
PA2H6
PA2H5
PA2H4
PA2H3
PA2H2
PA2H1
PA2H0
PA1H7
PA1H6
PA1H5
PA1H4
PA1H3
PA1H2
PA1H1
PA1H0
PA0H7
PA0H6
PA0H5
PA0H4
PA0H3
PA0H2
PA0H1
PA0H0
MCCNT15
MCCNT14
MCCNT13
MCCNT12
MCCNT11
MCCNT10
MCCNT9
MCCNT8
MCCNT7
MCCNT6
MCCNT5
MCCNT4
MCCNT3
MCCNT2
MCCNT1
MCCNT9
TC15
TC14
TC13
TC12
TC11
TC10
TC9
TC8
TC7
TC6
TC5
TC4
TC3
TC2
TC1
TC0
W
PA3H
PBOVI
PBOVF
0
W
PA2H
R
W
PA1H
R
W
PA0H
R
W
MCCNT
(High)
MCCNT
(Low)
R
W
R
W
TC0H (High) R
W
TC0H (Low) R
= Unimplemented or Reserved
Figure 7-2. ECT Register Summary (Sheet 4 of 5)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
317
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Register
Name
TC1H (High) R
Bit 7
6
5
4
3
2
1
Bit 0
TC15
TC14
TC13
TC12
TC11
TC10
TC9
TC8
TC7
TC6
TC5
TC4
TC3
TC2
TC1
TC0
TC15
TC14
TC13
TC12
TC11
TC10
TC9
TC8
TC7
TC6
TC5
TC4
TC3
TC2
TC1
TC0
TC15
TC14
TC13
TC12
TC11
TC10
TC9
TC8
TC7
TC6
TC5
TC4
TC3
TC2
TC1
TC0
W
TC1H (Low) R
W
TC2H (High) R
W
TC2H (Low) R
W
TC3H (High) R
W
TC3H (Low) R
W
= Unimplemented or Reserved
Figure 7-2. ECT Register Summary (Sheet 5 of 5)
7.3.2.1
R
W
Reset
Timer Input Capture/Output Compare Select Register (TIOS)
7
6
5
4
3
2
1
0
IOS7
IOS6
IOS5
IOS4
IOS3
IOS2
IOS1
IOS0
0
0
0
0
0
0
0
0
Figure 7-3. Timer Input Capture/Output Compare Register (TIOS)
Read or write: Anytime
All bits reset to zero.
Table 7-2. TIOS Field Descriptions
Field
7:0
IOS[7:0]
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
318
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.2
Timer Compare Force Register (CFORC)
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 7-4. Timer Compare Force Register (CFORC)
Read or write: Anytime but reads will always return 0x0000 (1 state is transient).
All bits reset to zero.
Table 7-3. 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 successful channel 7 output compare overrides any channel 6:0 compares. If a forced output compare
on any channel occurs at the same time as the successful output compare, then the forced output compare
action will take precedence and the interrupt flag will not get set.
7.3.2.3
R
W
Reset
Output Compare 7 Mask Register (OC7M)
7
6
5
4
3
2
1
0
OC7M7
OC7M6
OC7M5
OC7M4
OC7M3
OC7M2
OC7M1
OC7M0
0
0
0
0
0
0
0
0
Figure 7-5. Output Compare 7 Mask Register (OC7M)
Read or write: Anytime
All bits reset to zero.
Table 7-4. OC7M Field Descriptions
Field
Description
7:0
OC7M[7:0]
Output Compare Mask Action for Channel 7:0
0 The corresponding OC7Dx bit in the output compare 7 data register will not be transferred to the timer port on
a successful channel 7 output compare, 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
successful channel 7 output compare.
Note: The corresponding channel must also be setup for output compare (IOSx = 1) for data to be transferred
from the output compare 7 data register to the timer port.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
319
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.4
R
W
Reset
Output Compare 7 Data Register (OC7D)
7
6
5
4
3
2
1
0
OC7D7
OC7D6
OC7D5
OC7D4
OC7D3
OC7D2
OC7D1
OC7D0
0
0
0
0
0
0
0
0
Figure 7-6. Output Compare 7 Data Register (OC7D)
Read or write: Anytime
All bits reset to zero.
Table 7-5. OC7D Field Descriptions
Field
7:0
OC7D[7:0]
Description
Output Compare 7 Data Bits — A channel 7 output compare 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
320
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.5
R
W
Reset
Timer Count Register (TCNT)
15
14
13
12
11
10
9
8
TCNT15
TCNT14
TCNT13
TCNT12
TCNT11
TCNT10
TCNT9
TCNT8
0
0
0
0
0
0
0
0
Figure 7-7. Timer Count Register High (TCNT)
R
W
Reset
7
6
5
4
3
2
1
0
TCNT7
TCNT6
TCNT5
TCNT4
TCNT3
TCNT2
TCNT1
TCNT0
0
0
0
0
0
0
0
0
Figure 7-8. Timer Count Register Low (TCNT)
Read: Anytime
Write: Has no meaning or effect
All bits reset to zero.
Table 7-6. TCNT Field Descriptions
Field
Description
15:0
Timer Counter Bits — The 16-bit main timer is an up counter. A read to this register will return the current value
TCNT[15:0] of the counter. Access to the counter register will take place in one clock cycle.
Note: A separate read/write for high byte and low byte in test mode will give a different result than accessing them
as a word. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
321
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.6
Timer System Control Register 1 (TSCR1)
7
R
W
Reset
6
5
4
3
TEN
TSWAI
TSFRZ
TFFCA
PRNT
0
0
0
0
0
2
1
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 7-9. Timer System Control Register 1 (TSCR1)
Read or write: Anytime except PRNT bit is write once
All bits reset to zero.
Table 7-7. TSCR1 Field Descriptions
Field
Description
7
TEN
Timer Enable
0 Disables the main timer, including the counter. Can be used for reducing power consumption.
1 Allows the timer to function normally.
Note: If for any reason the timer is not active, there is no ÷64 clock for the pulse accumulator since 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 counter, pulse accumulators and modulus down counter when the MCU is in wait mode.
Timer interrupts cannot be used to get the MCU out of wait.
5
TSFRZ
Timer and Modulus Counter Stop While in Freeze Mode
0 Allows the timer and modulus counter to continue running while in freeze mode.
1 Disables the timer and modulus counter whenever the MCU is in freeze mode. This is useful for emulation.
The pulse accumulators do not stop in freeze mode.
4
TFFCA
Timer Fast Flag Clear All
0 Allows the timer flag clearing to function normally.
1 A read from an input capture or a write to the output compare channel registers causes the corresponding
channel flag, CxF, to be cleared in the TFLG1 register. Any access to the TCNT register clears the TOF flag
in the TFLG2 register. Any access to the PACN3 and PACN2 registers clears the PAOVF and PAIF flags in the
PAFLG register. Any access to the PACN1 and PACN0 registers clears the PBOVF flag in the PBFLG register.
Any access to the MCCNT register clears the MCZF flag in the MCFLG register. 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.
Note: The flags cannot be cleared via the normal flag clearing mechanism (writing a one to the flag) when
TFFCA = 1.
3
PRNT
Precision Timer
0 Enables legacy timer. Only bits DLY0 and DLY1 of the DLYCT register are used for the delay selection of the
delay counter. PR0, PR1, and PR2 bits of the TSCR2 register are used for timer counter prescaler selection.
MCPR0 and MCPR1 bits of the MCCTL register are used for modulus down counter prescaler selection.
1 Enables precision timer. All bits in the DLYCT register are used for the delay selection, all bits of the PTPSR
register are used for Precision Timer Prescaler Selection, and all bits of PTMCPSR register are used for the
prescaler Precision Timer Modulus Counter Prescaler selection.
MC9S12XDP512 Data Sheet, Rev. 2.21
322
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.7
R
W
Reset
Timer Toggle On Overflow Register 1 (TTOV)
7
6
5
4
3
2
1
0
TOV7
TOV6
TOV5
TOV4
TOV3
TOV2
TOV1
TOV0
0
0
0
0
0
0
0
0
Figure 7-10. Timer Toggle On Overflow Register 1 (TTOV)
Read or write: Anytime
All bits reset to zero.
Table 7-8. TTOV Field Descriptions
Field
Description
7:0
TOV[7:0]
Toggle On Overflow Bits — TOV97:0] toggles output compare pin on timer counter 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
323
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.8
R
W
Reset
Timer Control Register 1/Timer Control Register 2 (TCTL1/TCTL2)
7
6
5
4
3
2
1
0
OM7
OL7
OM6
OL6
OM5
OL5
OM4
OL4
0
0
0
0
0
0
0
0
Figure 7-11. Timer Control Register 1 (TCTL1)
R
W
Reset
7
6
5
4
3
2
1
0
OM3
OL3
OM2
OL2
OM1
OL1
OM0
OL0
0
0
0
0
0
0
0
0
Figure 7-12. Timer Control Register 2 (TCTL2)
Read or write: Anytime
All bits reset to zero.
Table 7-9. TCTL1/TCTL2 Field Descriptions
Field
Description
OM[7:0]
7, 5, 3, 1
OMx — Output Mode
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 one, the pin associated with OCx becomes an output tied to OCx.
See Table 7-10.
OL[7:0]
6, 4, 2, 0
Table 7-10. Compare Result Output Action
OMx
OLx
Action
0
0
Timer disconnected from output pin logic
0
1
Toggle OCx output line
1
0
Clear OCx output line to zero
1
1
Set OCx output line to one
NOTE
To enable output action by OMx and OLx bits on timer port, the
corresponding bit in OC7M should be cleared.
MC9S12XDP512 Data Sheet, Rev. 2.21
324
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.9
R
W
Reset
Timer Control Register 3/Timer Control Register 4 (TCTL3/TCTL4)
7
6
5
4
3
2
1
0
EDG7B
EDG7A
EDG6B
EDG6A
EDG5B
EDG5A
EDG4B
EDG4A
0
0
0
0
0
0
0
0
Figure 7-13. Timer Control Register 3 (TCTL3)
R
W
Reset
7
6
5
4
3
2
1
0
EDG3B
EDG3A
EDG2B
EDG2A
EDG1B
EDG1A
EDG0B
EDG0A
0
0
0
0
0
0
0
0
Figure 7-14. Timer Control Register 4 (TCTL4)
Read or write: Anytime
All bits reset to zero.
Table 7-11. TCTL3/TCTL4 Field Descriptions
Field
Description
EDG[7:0]B
7, 5, 3, 1
Input Capture Edge Control — These eight pairs of control bits configure the input capture edge detector
circuits for each input capture channel. The four pairs of control bits in TCTL4 also configure the input capture
edge control for the four 8-bit pulse accumulators PAC0–PAC3.EDG0B and EDG0A in TCTL4 also determine the
active edge for the 16-bit pulse accumulator PACB. See Table 7-12.
EDG[7:0]A
6, 4, 2, 0
Table 7-12. Edge Detector Circuit Configuration
EDGxB
EDGxA
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)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
325
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.10
R
W
Reset
Timer Interrupt Enable Register (TIE)
7
6
5
4
3
2
1
0
C7I
C6I
C5I
C4I
C3I
C2I
C1I
C0I
0
0
0
0
0
0
0
0
Figure 7-15. Timer Interrupt Enable Register (TIE)
Read or write: Anytime
All bits reset to zero.
The bits C7I–C0I correspond bit-for-bit with the flags in the TFLG1 status register.
Table 7-13. TIE Field Descriptions
Field
7:0
C[7:0]I
Description
Input Capture/Output Compare “x” Interrupt Enable
0 The corresponding flag is disabled from causing a hardware interrupt.
1 The corresponding flag is enabled to cause an interrupt.
MC9S12XDP512 Data Sheet, Rev. 2.21
326
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.11
Timer System Control Register 2 (TSCR2)
7
R
W
Reset
TOI
0
6
5
4
0
0
0
0
0
0
3
2
1
0
TCRE
PR2
PR1
PR0
0
0
0
0
= Unimplemented or Reserved
Figure 7-16. Timer System Control Register 2 (TSCR2)
Read or write: Anytime
All bits reset to zero.
Table 7-14. TSCR2 Field Descriptions
Field
7
TOI
Description
Timer Overflow Interrupt Enable
0 Timer overflow interrupt disabled.
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 channel 7 output
compare. This mode of operation is similar to an up-counting modulus counter.
0 Counter reset disabled and counter free runs.
1 Counter reset by a successful output compare on channel 7.
Note: If register TC7 = 0x0000 and TCRE = 1, then the TCNT register will stay at 0x0000 continuously. If register
TC7 = 0xFFFF and TCRE = 1, the TOF flag will never be set when TCNT is reset from 0xFFFF to 0x0000.
2:0
PR[2:0]
Timer Prescaler Select — These three bits specify the division rate of the main Timer prescaler when the PRNT
bit of register TSCR1 is set to 0. The newly selected prescale factor will not take effect until the next synchronized
edge where all prescale counter stages equal zero. See Table 7-15.
Table 7-15. Prescaler Selection
PR2
PR1
PR0
Prescale Factor
0
0
0
1
0
0
1
2
0
1
0
4
0
1
1
8
1
0
0
16
1
0
1
32
1
1
0
64
1
1
1
128
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
327
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.12
R
W
Reset
Main Timer Interrupt Flag 1 (TFLG1)
7
6
5
4
3
2
1
0
C7F
C6F
C5F
C4F
C3F
C2F
C1F
C0F
0
0
0
0
0
0
0
0
Figure 7-17. Main Timer Interrupt Flag 1 (TFLG1)
Read: Anytime
Write used in the flag clearing mechanism. Writing a one to the flag clears the flag. Writing a zero will not
affect the current status of the bit.
NOTE
When TFFCA = 1, the flags cannot be cleared via the normal flag clearing
mechanism (writing a one to the flag). Reference Section 7.3.2.6, “Timer
System Control Register 1 (TSCR1)”.
All bits reset to zero.
TFLG1 indicates when interrupt conditions have occurred. The flags can be cleared via the normal flag
clearing mechanism (writing a one to the flag) or via the fast flag clearing mechanism (reference TFFCA
bit in Section 7.3.2.6, “Timer System Control Register 1 (TSCR1)”).
Use of the TFMOD bit in the ICSYS register in conjunction with the use of the ICOVW register allows a
timer interrupt to be generated after capturing two values in the capture and holding registers, instead of
generating an interrupt for every capture.
Table 7-16. TFLG1 Field Descriptions
Field
Description
7:0
C[7:0]F
Input Capture/Output Compare Channel “x” Flag — A CxF flag is set when a corresponding input capture or
output compare is detected. C0F can also be set by 16-bit Pulse Accumulator B (PACB). C3F–C0F can also be
set by 8-bit pulse accumulators PAC3–PAC0.
If the delay counter is enabled, the CxF flag will not be set until after the delay.
MC9S12XDP512 Data Sheet, Rev. 2.21
328
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.13
Main Timer Interrupt Flag 2 (TFLG2)
7
R
W
Reset
TOF
0
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 7-18. Main Timer Interrupt Flag 2 (TFLG2)
Read: Anytime
Write used in the flag clearing mechanism. Writing a one to the flag clears the flag. Writing a zero will not
affect the current status of the bit.
NOTE
When TFFCA = 1, the flag cannot be cleared via the normal flag clearing
mechanism (writing a one to the flag). Reference Section 7.3.2.6, “Timer
System Control Register 1 (TSCR1)”.
All bits reset to zero.
TFLG2 indicates when interrupt conditions have occurred. The flag can be cleared via the normal flag
clearing mechanism (writing a one to the flag) or via the fast flag clearing mechanism (Reference TFFCA
bit in Section 7.3.2.6, “Timer System Control Register 1 (TSCR1)”).
Table 7-17. TFLG2 Field Descriptions
Field
7
TOF
Description
Timer Overflow Flag — Set when 16-bit free-running timer overflows from 0xFFFF to 0x0000.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
329
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.14
R
W
Reset
Timer Input Capture/Output Compare Registers 0–7
15
14
13
12
11
10
9
8
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 7-19. Timer Input Capture/Output Compare Register 0 High (TC0)
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 7-20. Timer Input Capture/Output Compare Register 0 Low (TC0)
R
W
Reset
15
14
13
12
11
10
9
8
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 7-21. Timer Input Capture/Output Compare Register 1 High (TC1)
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 7-22. Timer Input Capture/Output Compare Register 1 Low (TC1)
R
W
Reset
15
14
13
12
11
10
9
8
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 7-23. Timer Input Capture/Output Compare Register 2 High (TC2)
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 7-24. Timer Input Capture/Output Compare Register 2 Low (TC2)
R
W
Reset
15
14
13
12
11
10
9
8
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 7-25. Timer Input Capture/Output Compare Register 3 High (TC3)
MC9S12XDP512 Data Sheet, Rev. 2.21
330
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
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 7-26. Timer Input Capture/Output Compare Register 3 Low (TC3)
R
W
Reset
15
14
13
12
11
10
9
8
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 7-27. Timer Input Capture/Output Compare Register 4 High (TC4)
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 7-28. Timer Input Capture/Output Compare Register 4 Low (TC4)
R
W
Reset
15
14
13
12
11
10
9
8
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 7-29. Timer Input Capture/Output Compare Register 5 High (TC5)
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 7-30. Timer Input Capture/Output Compare Register 5 Low (TC5)
R
W
Reset
15
14
13
12
11
10
9
8
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 7-31. Timer Input Capture/Output Compare Register 6 High (TC6)
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 7-32. Timer Input Capture/Output Compare Register 6 Low (TC6)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
331
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
R
W
Reset
15
14
13
12
11
10
9
8
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 7-33. Timer Input Capture/Output Compare Register 7 High (TC7)
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 7-34. Timer Input Capture/Output Compare Register 7 Low (TC7)
Read: Anytime
Write anytime for output compare function. Writes to these registers have no meaning or effect during
input capture.
All bits reset to zero.
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.
7.3.2.15
16-Bit Pulse Accumulator A Control Register (PACTL)
7
R
0
W
Reset
0
6
5
4
3
2
1
0
PAEN
PAMOD
PEDGE
CLK1
CLK0
PAOVI
PAI
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 7-35. 16-Bit Pulse Accumulator Control Register (PACTL)
Read: Anytime
Write: Anytime
All bits reset to zero.
Table 7-18. PACTL Field Descriptions
Field
Description
6
PAEN
Pulse Accumulator A System Enable — PAEN is independent from TEN. With timer disabled, the pulse
accumulator can still function unless pulse accumulator is disabled.
0 16-Bit Pulse Accumulator A system disabled. 8-bit PAC3 and PAC2 can be enabled when their related enable
bits in ICPAR are set. Pulse Accumulator Input Edge Flag (PAIF) function is disabled.
1 16-Bit Pulse Accumulator A system enabled. The two 8-bit pulse accumulators PAC3 and PAC2 are cascaded
to form the PACA 16-bit pulse accumulator. When PACA in enabled, the PACN3 and PACN2 registers contents
are respectively the high and low byte of the PACA. PA3EN and PA2EN control bits in ICPAR have no effect.
Pulse Accumulator Input Edge Flag (PAIF) function is enabled. The PACA shares the input pin with IC7.
MC9S12XDP512 Data Sheet, Rev. 2.21
332
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Table 7-18. PACTL Field Descriptions (continued)
Field
Description
5
PAMOD
Pulse Accumulator Mode — This bit is active only when the Pulse Accumulator A is enabled (PAEN = 1).
0 Event counter mode
1 Gated time accumulation mode
4
PEDGE
Pulse Accumulator Edge Control — This bit is active only when the Pulse Accumulator A is enabled
(PAEN = 1). Refer to Table 7-19.
For PAMOD bit = 0 (event counter mode).
0 Falling edges on PT7 pin cause the count to be incremented
1 Rising edges on PT7 pin cause the count to be incremented
For PAMOD bit = 1 (gated time accumulation mode).
0 PT7 input pin high enables bus clock divided by 64 to Pulse Accumulator and the trailing falling edge on PT7
sets the PAIF flag.
1 PT7 input pin low enables bus clock divided by 64 to Pulse Accumulator and the trailing rising edge on PT7
sets the PAIF flag.
If the timer is not active (TEN = 0 in TSCR1), there is no divide-by-64 since the ÷64 clock is generated by the
timer prescaler.
3:2
CLK[1:0]
2
PAOVI
0
PAI
Clock Select Bits — For the description of PACLK please refer to Figure 7-70.
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. Refer to Table 7-20.
Pulse Accumulator A 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
.
Table 7-19. Pin Action
PAMOD
PEDGE
Pin Action
0
0
Falling edge
0
1
Rising edge
1
0
Divide by 64 clock enabled with pin high level
1
1
Divide by 64 clock enabled with pin low level
Table 7-20. Clock Selection
CLK1
CLK0
Clock Source
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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
333
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.16
R
Pulse Accumulator A Flag Register (PAFLG)
7
6
5
4
3
2
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
1
0
PAOVF
PAIF
0
0
= Unimplemented or Reserved
Figure 7-36. Pulse Accumulator A Flag Register (PAFLG)
Read: Anytime
Write used in the flag clearing mechanism. Writing a one to the flag clears the flag. Writing a zero will not
affect the current status of the bit.
NOTE
When TFFCA = 1, the flags cannot be cleared via the normal flag clearing
mechanism (writing a one to the flag). Reference Section 7.3.2.6, “Timer
System Control Register 1 (TSCR1)”.
All bits reset to zero.
PAFLG indicates when interrupt conditions have occurred. The flags can be cleared via the normal flag
clearing mechanism (writing a one to the flag) or via the fast flag clearing mechanism (Reference TFFCA
bit in Section 7.3.2.6, “Timer System Control Register 1 (TSCR1)”).
Table 7-21. PAFLG Field Descriptions
Field
Description
1
PAOVF
Pulse Accumulator A Overflow Flag — Set when the 16-bit pulse accumulator A overflows from 0xFFFF to
0x0000, or when 8-bit pulse accumulator 3 (PAC3) overflows from 0x00FF to 0x0000.
When PACMX = 1, PAOVF bit can also be set if 8-bit pulse accumulator 3 (PAC3) reaches 0x00FF followed by
an active edge on PT3.
0
PAIF
Pulse Accumulator Input edge Flag — Set when the selected edge is detected at the PT7 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 PT7 input pin triggers PAIF.
7.3.2.17
Pulse Accumulators Count Registers (PACN3 and PACN2)
7
R
W
Reset
6
5
4
3
2
PACNT7(15) PACNT6(14) PACNT5(13) PACNT4(12) PACNT3(11) PACNT2(10)
0
0
0
0
0
0
1
0
PACNT1(9)
PACNT0(8)
0
0
Figure 7-37. Pulse Accumulators Count Register 3 (PACN3)
MC9S12XDP512 Data Sheet, Rev. 2.21
334
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
R
W
Reset
7
6
5
4
3
2
1
0
PACNT7
PACNT6
PACNT5
PACNT4
PACNT3
PACNT2
PACNT1
PACNT0
0
0
0
0
0
0
0
0
Figure 7-38. Pulse Accumulators Count Register 2 (PACN2)
Read: Anytime
Write: Anytime
All bits reset to zero.
The two 8-bit pulse accumulators PAC3 and PAC2 are cascaded to form the PACA 16-bit pulse
accumulator. When PACA in enabled (PAEN = 1 in PACTL), the PACN3 and PACN2 registers contents
are respectively the high and low byte of the PACA.
When PACN3 overflows from 0x00FF to 0x0000, the interrupt flag PAOVF in PAFLG is set.
Full count register access will take place in one clock cycle.
NOTE
A separate read/write for high byte and low byte will give a different result
than accessing them as a word.
When clocking pulse and write to the registers occurs simultaneously, write
takes priority and the register is not incremented.
7.3.2.18
Pulse Accumulators Count Registers (PACN1 and PACN0)
7
R
W
Reset
6
5
4
3
2
PACNT7(15) PACNT6(14) PACNT5(13) PACNT4(12) PACNT3(11) PACNT2(10)
0
0
0
0
0
0
1
0
PACNT1(9)
PACNT0(8)
0
0
Figure 7-39. Pulse Accumulators Count Register 1 (PACN1)
R
W
Reset
7
6
5
4
3
2
1
0
PACNT7
PACNT6
PACNT5
PACNT4
PACNT3
PACNT2
PACNT1
PACNT0
0
0
0
0
0
0
0
0
Figure 7-40. Pulse Accumulators Count Register 0 (PACN0)
Read: Anytime
Write: Anytime
All bits reset to zero.
The two 8-bit pulse accumulators PAC1 and PAC0 are cascaded to form the PACB 16-bit pulse
accumulator. When PACB in enabled, (PBEN = 1 in PBCTL) the PACN1 and PACN0 registers contents
are respectively the high and low byte of the PACB.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
335
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
When PACN1 overflows from 0x00FF to 0x0000, the interrupt flag PBOVF in PBFLG is set.
Full count register access will take place in one clock cycle.
NOTE
A separate read/write for high byte and low byte will give a different result
than accessing them as a word.
When clocking pulse and write to the registers occurs simultaneously, write
takes priority and the register is not incremented.
MC9S12XDP512 Data Sheet, Rev. 2.21
336
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.19
16-Bit Modulus Down-Counter Control Register (MCCTL)
7
R
W
Reset
6
5
MCZI
MODMC
RDMCL
0
0
0
4
3
0
0
ICLAT
FLMC
0
0
2
1
0
MCEN
MCPR1
MCPR0
0
0
0
Figure 7-41. 16-Bit Modulus Down-Counter Control Register (MCCTL)
Read: Anytime
Write: Anytime
All bits reset to zero.
Table 7-22. MCCTL Field Descriptions
Field
7
MCZI
Description
Modulus Counter Underflow Interrupt Enable
0 Modulus counter interrupt is disabled.
1 Modulus counter interrupt is enabled.
6
MODMC
Modulus Mode Enable
0 The modulus counter counts down from the value written to it and will stop at 0x0000.
1 Modulus mode is enabled. When the modulus counter reaches 0x0000, the counter is loaded with the latest
value written to the modulus count register.
Note: For proper operation, the MCEN bit should be cleared before modifying the MODMC bit in order to reset
the modulus counter to 0xFFFF.
5
RDMCL
Read Modulus Down-Counter Load
0 Reads of the modulus count register (MCCNT) will return the present value of the count register.
1 Reads of the modulus count register (MCCNT) will return the contents of the load register.
4
ICLAT
Input Capture Force Latch Action — When input capture latch mode is enabled (LATQ and BUFEN bit in
ICSYS are set), a write one to this bit immediately forces the contents of the input capture registers TC0 to TC3
and their corresponding 8-bit pulse accumulators to be latched into the associated holding registers. The pulse
accumulators will be automatically cleared when the latch action occurs.
Writing zero to this bit has no effect. Read of this bit will always return zero.
3
FLMC
Force Load Register into the Modulus Counter Count Register — This bit is active only when the modulus
down-counter is enabled (MCEN = 1).
A write one into this bit loads the load register into the modulus counter count register (MCCNT). This also resets
the modulus counter prescaler.
Write zero to this bit has no effect. Read of this bit will return always zero.
2
MCEN
1:0
MCPR[1:0]
Modulus Down-Counter Enable
0 Modulus counter disabled. The modulus counter (MCCNT) is preset to 0xFFFF. This will prevent an early
interrupt flag when the modulus down-counter is enabled.
1 Modulus counter is enabled.
Modulus Counter Prescaler Select — These two bits specify the division rate of the modulus counter prescaler
when PRNT of TSCR1 is set to 0. The newly selected prescaler division rate will not be effective until a load of
the load register into the modulus counter count register occurs.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
337
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Table 7-23. Modulus Counter Prescaler Select
7.3.2.20
W
Reset
MCPR0
Prescaler Division
0
0
1
0
1
4
1
0
8
1
1
16
16-Bit Modulus Down-Counter FLAG Register (MCFLG)
7
R
MCPR1
MCZF
0
6
5
4
3
2
1
0
0
0
0
POLF3
POLF2
POLF1
POLF0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 7-42. 16-Bit Modulus Down-Counter FLAG Register (MCFLG)
Read: Anytime
Write only used in the flag clearing mechanism for bit 7. Writing a one to bit 7 clears the flag. Writing a
zero will not affect the current status of the bit.
NOTE
When TFFCA = 1, the flag cannot be cleared via the normal flag clearing
mechanism (writing a one to the flag). Reference Section 7.3.2.6, “Timer
System Control Register 1 (TSCR1)”.
All bits reset to zero.
Table 7-24. MCFLG Field Descriptions
Field
7
MCZF
3:0
POLF[3:0]
Description
Modulus Counter Underflow Flag — The flag is set when the modulus down-counter reaches 0x0000.
The flag indicates when interrupt conditions have occurred. The flag can be cleared via the normal flag clearing
mechanism (writing a one to the flag) or via the fast flag clearing mechanism (Reference TFFCA bit in
Section 7.3.2.6, “Timer System Control Register 1 (TSCR1)”).
First Input Capture Polarity Status — These are read only bits. Writes to these bits have no effect.
Each status bit gives the polarity of the first edge which has caused an input capture to occur after capture latch
has been read.
Each POLFx corresponds to a timer PORTx input.
0 The first input capture has been caused by a falling edge.
1 The first input capture has been caused by a rising edge.
MC9S12XDP512 Data Sheet, Rev. 2.21
338
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.21
R
ICPAR — Input Control Pulse Accumulators Register (ICPAR)
7
6
5
4
0
0
0
0
0
0
0
0
W
Reset
3
2
1
0
PA3EN
PA2EN
PA1EN
PA0EN
0
0
0
0
= Unimplemented or Reserved
Figure 7-43. Input Control Pulse Accumulators Register (ICPAR)
Read: Anytime
Write: Anytime.
All bits reset to zero.
The 8-bit pulse accumulators PAC3 and PAC2 can be enabled only if PAEN in PACTL is cleared. If PAEN
is set, PA3EN and PA2EN have no effect.
The 8-bit pulse accumulators PAC1 and PAC0 can be enabled only if PBEN in PBCTL is cleared. If PBEN
is set, PA1EN and PA0EN have no effect.
Table 7-25. ICPAR Field Descriptions
Field
3:0
PA[3:0]EN
Description
8-Bit Pulse Accumulator ‘x’ Enable
0 8-Bit Pulse Accumulator is disabled.
1 8-Bit Pulse Accumulator is enabled.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
339
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.22
R
W
Reset
Delay Counter Control Register (DLYCT)
7
6
5
4
3
2
1
0
DLY7
DLY6
DLY5
DLY4
DLY3
DLY2
DLY1
DLY0
0
0
0
0
0
0
0
0
Figure 7-44. Delay Counter Control Register (DLYCT)
Read: Anytime
Write: Anytime
All bits reset to zero.
Table 7-26. DLYCT Field Descriptions
Field
7:0
DLY[7:0]
Description
Delay Counter Select — When the PRNT bit of TSCR1 register is set to 0, only bits DLY0, DLY1 are used to
calculate the delay.Table 7-27 shows the delay settings in this case.
When the PRNT bit of TSCR1 register is set to 1, all bits are used to set a more precise delay. Table 7-28 shows
the delay settings in this case. After detection of a valid edge on an input capture pin, the delay counter counts
the pre-selected number of [(dly_cnt + 1)*4]bus clock cycles, then it will generate a pulse on its output if the level
of input signal, after the preset delay, is the opposite of the level before the transition.This will avoid reaction to
narrow input pulses.
Delay between two active edges of the input signal period should be longer than the selected counter delay.
Note: It is recommended to not write to this register while the timer is enabled, that is when TEN is set in register
TSCR1.
Table 7-27. Delay Counter Select when PRNT = 0
DLY1
DLY0
Delay
0
0
1
1
0
1
0
1
Disabled
256 bus clock cycles
512 bus clock cycles
1024 bus clock cycles
Table 7-28. Delay Counter Select Examples when PRNT = 1
DLY7
DLY6
DLY5
DLY4
DLY3
DLY2
DLY1
DLY0
Delay
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
0
0
0
0
1
1
1
1
1
1
1
1
1
0
0
1
1
0
0
1
1
1
1
1
1
1
0
1
0
1
0
1
0
1
1
1
1
1
1
Disabled (bypassed)
8 bus clock cycles
12 bus clock cycles
16 bus clock cycles
20 bus clock cycles
24 bus clock cycles
28 bus clock cycles
32 bus clock cycles
64 bus clock cycles
128 bus clock cycles
256 bus clock cycles
512 bus clock cycles
1024 bus clock cycles
MC9S12XDP512 Data Sheet, Rev. 2.21
340
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.23
R
W
Reset
Input Control Overwrite Register (ICOVW)
7
6
5
4
3
2
1
0
NOVW7
NOVW6
NOVW5
NOVW4
NOVW3
NOVW2
NOVW1
NOVW0
0
0
0
0
0
0
0
0
Figure 7-45. Input Control Overwrite Register (ICOVW)
Read: Anytime
Write: Anytime
All bits reset to zero.
Table 7-29. ICOVW Field Descriptions
Field
Description
7:0
NOVW[7:0]
No Input Capture Overwrite
0 The contents of the related capture register or holding register can be overwritten when a new input capture
or latch occurs.
1 The related capture register or holding register cannot be written by an event unless they are empty (see
Section 7.4.1.1, “IC Channels”). This will prevent the captured value being overwritten until it is read or latched
in the holding register.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
341
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.24
R
W
Reset
Input Control System Control Register (ICSYS)
7
6
5
4
3
2
1
0
SH37
SH26
SH15
SH04
TFMOD
PACMX
BUFEN
LATQ
0
0
0
0
0
0
0
0
Figure 7-46. Input Control System Register (ICSYS)
Read: Anytime
Write: Once in normal modes
All bits reset to zero.
Table 7-30. ICSYS Field Descriptions
Field
Description
7:4
SHxy
Share Input action of Input Capture Channels x and y
0 Normal operation
1 The channel input ‘x’ causes the same action on the channel ‘y’. The port pin ‘x’ and the corresponding edge
detector is used to be active on the channel ‘y’.
3
TFMOD
Timer Flag Setting Mode — Use of the TFMOD bit in conjunction with the use of the ICOVW register allows a
timer interrupt to be generated after capturing two values in the capture and holding registers instead of
generating an interrupt for every capture.
By setting TFMOD in queue mode, when NOVWx bit is set and the corresponding capture and holding registers
are emptied, an input capture event will first update the related input capture register with the main timer
contents. At the next event, the TCx data is transferred to the TCxH register, the TCx is updated and the CxF
interrupt flag is set. In all other input capture cases the interrupt flag is set by a valid external event on PTx.
0 The timer flags C3F–C0F in TFLG1 are set when a valid input capture transition on the corresponding port pin
occurs.
1 If in queue mode (BUFEN = 1 and LATQ = 0), the timer flags C3F–C0F in TFLG1 are set only when a latch
on the corresponding holding register occurs. If the queue mode is not engaged, the timer flags C3F–C0F are
set the same way as for TFMOD = 0.
2
PACMX
8-Bit Pulse Accumulators Maximum Count
0 Normal operation. When the 8-bit pulse accumulator has reached the value 0x00FF, with the next active edge,
it will be incremented to 0x0000.
1 When the 8-bit pulse accumulator has reached the value 0x00FF, it will not be incremented further. The value
0x00FF indicates a count of 255 or more.
1
BUFFEN
IC Buffer Enable
0 Input capture and pulse accumulator holding registers are disabled.
1 Input capture and pulse accumulator holding registers are enabled. The latching mode is defined by LATQ
control bit.
MC9S12XDP512 Data Sheet, Rev. 2.21
342
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Table 7-30. ICSYS Field Descriptions (continued)
Field
Description
0
LATQ
Input Control Latch or Queue Mode Enable — The BUFEN control bit should be set in order to enable the IC
and pulse accumulators holding registers. Otherwise LATQ latching modes are disabled.
Write one into ICLAT bit in MCCTL, when LATQ and BUFEN are set will produce latching of input capture and
pulse accumulators registers into their holding registers.
0 Queue mode of Input Capture is enabled. The main timer value is memorized in the IC register by a valid input
pin transition. With a new occurrence of a capture, the value of the IC register will be transferred to its holding
register and the IC register memorizes the new timer value.
1 Latch mode is enabled. Latching function occurs when modulus down-counter reaches zero or a zero is
written into the count register MCCNT (see Section 7.4.1.1.2, “Buffered IC Channels”). With a latching event
the contents of IC registers and 8-bit pulse accumulators are transferred to their holding registers. 8-bit pulse
accumulators are cleared.
7.3.2.25
R
W
Reset
Precision Timer Prescaler Select Register (PTPSR)
7
6
5
4
3
2
1
0
PTPS7
PTPS6
PTPS5
PTPS4
PTPS3
PTPS2
PTPS1
PTPS0
0
0
0
0
0
0
0
0
Figure 7-47. Precision Timer Prescaler Select Register (PTPSR)
Read: Anytime
Write: Anytime
All bits reset to zero.
Table 7-31. 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 7-32 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.
Table 7-32. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
343
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Table 7-32. Precision Timer Prescaler Selection Examples when PRNT = 1
PTPS7
PTPS6
PTPS5
PTPS4
PTPS3
PTPS2
PTPS1
PTPS0
Prescale
Factor
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
7.3.2.26
R
W
Reset
Precision Timer Modulus Counter Prescaler Select Register (PTMCPSR)
7
6
5
4
3
2
1
0
PTMPS7
PTMPS6
PTMPS5
PTMPS4
PTMPS3
PTMPS2
PTMPS1
PTMPS0
0
0
0
0
0
0
0
0
Figure 7-48. Precision Timer Modulus Counter Prescaler Select Register (PTMCPSR)
Read: Anytime
Write: Anytime
All bits reset to zero.
Table 7-33. PTMCPSR Field Descriptions
Field
Description
7:0
Precision Timer Modulus Counter Prescaler Select Bits — These eight bits specify the division rate of the
PTMPS[7:0] modulus counter prescaler. These are effective only when the PRNT bit of TSCR1 is set to 1. Table 7-34 shows
some possible division rates.
The newly selected prescaler division rate will not be effective until a load of the load register into the modulus
counter count register occurs.
Table 7-34. Precision Timer Modulus Counter Prescaler Select Examples when PRNT = 1
PTMPS7
PTMPS6
PTMPS5
PTMPS4
PTMPS3
PTMPS2
PTMPS1
PTMPS0
Prescaler
Division
Rate
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
MC9S12XDP512 Data Sheet, Rev. 2.21
344
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Table 7-34. Precision Timer Modulus Counter Prescaler Select Examples when PRNT = 1 (continued)
PTMPS7
PTMPS6
PTMPS5
PTMPS4
PTMPS3
PTMPS2
PTMPS1
PTMPS0
Prescaler
Division
Rate
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
7.3.2.27
16-Bit Pulse Accumulator B Control Register (PBCTL)
7
R
6
0
PBEN
W
Reset
0
0
5
4
3
2
0
0
0
0
0
0
0
0
1
PBOVI
0
0
0
0
= Unimplemented or Reserved
Figure 7-49. 16-Bit Pulse Accumulator B Control Register (PBCTL)
Read: Anytime
Write: Anytime
All bits reset to zero.
Table 7-35. PBCTL Field Descriptions
Field
Description
6
PBEN
Pulse Accumulator B System Enable — PBEN is independent from TEN. With timer disabled, the pulse
accumulator can still function unless pulse accumulator is disabled.
0 16-bit pulse accumulator system disabled. 8-bit PAC1 and PAC0 can be enabled when their related enable bits
in ICPAR are set.
1 Pulse accumulator B system enabled. The two 8-bit pulse accumulators PAC1 and PAC0 are cascaded to form
the PACB 16-bit pulse accumulator B. When PACB is enabled, the PACN1 and PACN0 registers contents are
respectively the high and low byte of the PACB.
PA1EN and PA0EN control bits in ICPAR have no effect.
The PACB shares the input pin with IC0.
1
PBOVI
Pulse Accumulator B Overflow Interrupt Enable
0 Interrupt inhibited
1 Interrupt requested if PBOVF is set
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
345
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.28
R
Pulse Accumulator B Flag Register (PBFLG)
7
6
5
4
3
2
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
1
PBOVF
0
0
0
0
= Unimplemented or Reserved
Figure 7-50. Pulse Accumulator B Flag Register (PBFLG)
Read: Anytime
Write used in the flag clearing mechanism. Writing a one to the flag clears the flag. Writing a zero will not
affect the current status of the bit.
NOTE
When TFFCA = 1, the flag cannot be cleared via the normal flag clearing
mechanism (writing a one to the flag). Reference Section 7.3.2.6, “Timer
System Control Register 1 (TSCR1)”.
All bits reset to zero.
PBFLG indicates when interrupt conditions have occurred. The flag can be cleared via the normal flag
clearing mechanism (writing a one to the flag) or via the fast flag clearing mechanism (Reference TFFCA
bit in Section 7.3.2.6, “Timer System Control Register 1 (TSCR1)”).
Table 7-36. PBFLG Field Descriptions
Field
1
PBOVF
Description
Pulse Accumulator B Overflow Flag — This bit is set when the 16-bit pulse accumulator B overflows from
0xFFFF to 0x0000, or when 8-bit pulse accumulator 1 (PAC1) overflows from 0x00FF to 0x0000.
When PACMX = 1, PBOVF bit can also be set if 8-bit pulse accumulator 1 (PAC1) reaches 0x00FF and an active
edge follows on PT1.
MC9S12XDP512 Data Sheet, Rev. 2.21
346
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.29
R
8-Bit Pulse Accumulators Holding Registers (PA3H–PA0H)
7
6
5
4
3
2
1
0
PA3H7
PA3H6
PA3H5
PA3H4
PA3H3
PA3H2
PA3H1
PA3H0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 7-51. 8-Bit Pulse Accumulators Holding Register 3 (PA3H)
R
7
6
5
4
3
2
1
0
PA2H7
PA2H6
PA2H5
PA2H4
PA2H3
PA2H2
PA2H1
PA2H0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 7-52. 8-Bit Pulse Accumulators Holding Register 2 (PA2H)
R
7
6
5
4
3
2
1
0
PA1H7
PA1H6
PA1H5
PA1H4
PA1H3
PA1H2
PA1H1
PA1H0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 7-53. 8-Bit Pulse Accumulators Holding Register 1 (PA1H)
R
7
6
5
4
3
2
1
0
PA0H7
PA0H6
PA0H5
PA0H4
PA0H3
PA0H2
PA0H1
PA0H0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 7-54. 8-Bit Pulse Accumulators Holding Register 0 (PA0H)
Read: Anytime.
Write: Has no effect.
All bits reset to zero.
These registers are used to latch the value of the corresponding pulse accumulator when the related bits in
register ICPAR are enabled (see Section 7.4.1.3, “Pulse Accumulators”).
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
347
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.30
R
W
Reset
Modulus Down-Counter Count Register (MCCNT)
15
14
13
12
11
10
9
8
MCCNT15
MCCNT14
MCCNT13
MCCNT12
MCCNT11
MCCNT10
MCCNT9
MCCNT8
1
1
1
1
1
1
1
1
Figure 7-55. Modulus Down-Counter Count Register High (MCCNT)
R
W
Reset
7
6
5
4
3
2
1
0
MCCNT7
MCCNT6
MCCNT5
MCCNT4
MCCNT3
MCCNT2
MCCNT1
MCCNT9
1
1
1
1
1
1
1
1
Figure 7-56. Modulus Down-Counter Count Register Low (MCCNT)
Read: Anytime
Write: Anytime.
All bits reset to one.
A full access for the counter register will take place in one clock cycle.
NOTE
A separate read/write for high byte and low byte will give different results
than accessing them as a word.
If the RDMCL bit in MCCTL register is cleared, reads of the MCCNT register will return the present value
of the count register. If the RDMCL bit is set, reads of the MCCNT will return the contents of the load
register.
If a 0x0000 is written into MCCNT when LATQ and BUFEN in ICSYS register are set, the input capture
and pulse accumulator registers will be latched.
With a 0x0000 write to the MCCNT, the modulus counter will stay at zero and does not set the MCZF flag
in MCFLG register.
If the modulus down counter is enabled (MCEN = 1) and modulus mode is enabled (MODMC = 1), a write
to MCCNT will update the load register with the value written to it. The count register will not be updated
with the new value until the next counter underflow.
If modulus mode is not enabled (MODMC = 0), a write to MCCNT will clear the modulus prescaler and
will immediately update the counter register with the value written to it and down-counts to 0x0000 and
stops.
The FLMC bit in MCCTL can be used to immediately update the count register with the new value if an
immediate load is desired.
MC9S12XDP512 Data Sheet, Rev. 2.21
348
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.3.2.31
R
Timer Input Capture Holding Registers 0–3 (TCxH)
15
14
13
12
11
10
9
8
TC15
TC14
TC13
TC12
TC11
TC10
TC9
TC8
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 7-57. Timer Input Capture Holding Register 0 High (TC0H)
R
7
6
5
4
3
2
1
0
TC7
TC6
TC5
TC4
TC3
TC2
TC1
TC0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 7-58. Timer Input Capture Holding Register 0 Low (TC0H)
R
15
14
13
12
11
10
9
8
TC15
TC14
TC13
TC12
TC11
TC10
TC9
TC8
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 7-59. Timer Input Capture Holding Register 1 High (TC1H)
R
7
6
5
4
3
2
1
0
TC7
TC6
TC5
TC4
TC3
TC2
TC1
TC0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 7-60. Timer Input Capture Holding Register 1 Low (TC1H)
R
15
14
13
12
11
10
9
8
TC15
TC14
TC13
TC12
TC11
TC10
TC9
TC8
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 7-61. Timer Input Capture Holding Register 2 High (TC2H)
R
7
6
5
4
3
2
1
0
TC7
TC6
TC5
TC4
TC3
TC2
TC1
TC0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 7-62. Timer Input Capture Holding Register 2 Low (TC2H)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
349
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
R
15
14
13
12
11
10
9
8
TC15
TC14
TC13
TC12
TC11
TC10
TC9
TC8
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 7-63. Timer Input Capture Holding Register 3 High (TC3H)
R
7
6
5
4
3
2
1
0
TC7
TC6
TC5
TC4
TC3
TC2
TC1
TC0
0
0
0
0
0
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 7-64. Timer Input Capture Holding Register 3 Low (TC3H)
Read: Anytime
Write: Has no effect.
All bits reset to zero.
These registers are used to latch the value of the input capture registers TC0–TC3. The corresponding
IOSx bits in TIOS should be cleared (see Section 7.4.1.1, “IC Channels”).
7.4
Functional Description
This section provides a complete functional description of the ECT block, detailing the operation of the
design from the end user perspective in a number of subsections.
MC9S12XDP512 Data Sheet, Rev. 2.21
350
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Bus Clock
÷ 1, 4, 8, 16
Bus Clock
Timer Prescaler
16-Bit Load Register
16-Bit Modulus
Down Counter
Modulus Prescaler
0
P0
Comparator
Pin Logic
Delay
Counter
EDG0
TC0 Capture/Compare Reg.
PAC0
TC0H Hold Reg.
PA0H Hold Reg.
0
P1
Pin Logic
Delay
Counter
EDG1
TC1 Capture/Compare Reg.
PAC1
TC1H Hold Reg.
PA1H Hold Reg.
Pin Logic
Delay
Counter
EDG2
TC2 Capture/Compare Reg.
PAC2
TC2H Hold Reg.
PA2H Hold Reg.
Pin Logic
Pin Logic
RESET
Comparator
Delay
Counter
EDG3
TC3 Capture/Compare Reg.
PAC3
TC3H Hold Reg.
PA3H Hold Reg.
LATCH
P4
RESET
Comparator
0
P3
RESET
Comparator
0
P2
RESET
Underflow
16-Bit Free-Running
16 BITMain
MAIN
TIMER
Timer
÷ 1, 2, ..., 128
Comparator
EDG4
EDG0
TC4 Capture/Compare Reg.
MUX
ICLAT, LATQ, BUFEN
(Force Latch)
SH04
P5
Pin Logic
Comparator
EDG5
EDG1
TC5 Capture/Compare Reg.
MUX
Write 0x0000
to Modulus Counter
SH15
P6
Pin Logic
Comparator
EDG6
EDG2
LATQ
(MDC Latch Enable)
TC6 Capture/Compare Reg.
MUX
SH26
P7
Pin Logic
Comparator
EDG7
EDG3
TC7 Capture/Compare Reg.
MUX
SH37
Figure 7-65. Detailed Timer Block Diagram in Latch Mode when PRNT = 0
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
351
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Bus Clock
÷ 1, 2,3, ..., 256
Bus Clock
Timer Prescaler
16-Bit Load Register
16-Bit Modulus
Down Counter
Modulus Prescaler
0
P0
RESET
Underflow
16-Bit Free-Running
16 BITMain
MAINTimer
TIMER
÷ 1, 2,3, ..., 256
Comparator
Pin Logic
Delay
Counter
EDG0
TC0 Capture/Compare Reg.
PAC0
TC0H Hold Reg.
PA0H Hold Reg.
8, 12, 16, ..., 1024
0
P1
RESET
Comparator
Pin Logic
Delay
Counter
EDG1
TC1 Capture/Compare Reg.
PAC1
TC1H Hold Reg.
PA1H Hold Reg.
8, 12, 16, ..., 1024
0
P2
RESET
Comparator
Pin Logic
Delay
Counter
EDG2
TC2 Capture/Compare Reg.
PAC2
TC2H Hold Reg.
PA2H Hold Reg.
8, 12, 16, ..., 1024
0
P3
RESET
Comparator
Pin Logic
Delay
Counter
EDG3
TC3 Capture/Compare Reg.
PAC3
TC3H Hold Reg.
PA3H Hold Reg.
P4
Pin Logic
LATCH
8, 12, 16, ..., 1024
Comparator
EDG4
EDG0
TC4 Capture/Compare Reg.
MUX
ICLAT, LATQ, BUFEN
(Force Latch)
SH04
P5
Pin Logic
Comparator
EDG5
EDG1
TC5 Capture/Compare Reg.
MUX
Write 0x0000
to Modulus Counter
SH15
P6
Pin Logic
Comparator
EDG6
EDG2
LATQ
(MDC Latch Enable)
TC6 Capture/Compare Reg.
MUX
SH26
P7
Pin Logic
Comparator
EDG7
EDG3
TC7 Capture/Compare Reg.
MUX
SH37
Figure 7-66. Detailed Timer Block Diagram in Latch Mode when PRNT = 1
MC9S12XDP512 Data Sheet, Rev. 2.21
352
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
16-Bit Free-Running
16 BITMain
MAIN
TIMER
Timer
÷ 1, 4, 8, 16
Bus Clock
16-Bit Load Register
16-Bit Modulus
Down Counter
Modulus
Prescaler
0
Delay
Counter
EDG0
TC0 Capture/Compare Reg.
PAC0
TC0H Hold Reg.
PA0H Hold Reg.
0
Pin Logic
Delay
Counter
EDG1
TC1 Capture/Compare Reg.
PAC1
TC1H Hold Reg.
PA1H Hold Reg.
0
P2
P4
Pin Logic
Delay
Counter
EDG2
TC2 Capture/Compare Reg.
PAC2
TC2H Hold Reg.
PA2H Hold Reg.
Delay
Counter
EDG3
TC3 Capture/Compare Reg.
PAC3
TC3H Hold Reg.
PA3H Hold Reg.
Comparator
EDG4
TC4 Capture/Compare Reg.
LATQ, BUFEN
(Queue Mode)
Comparator
Read TC3H
Hold Reg.
MUX
EDG0
SH04
P5
Pin Logic
EDG5
TC5 Capture/Compare Reg.
MUX
EDG1
Read TC2H
Hold Reg.
SH15
P6
Pin Logic
RESET
Comparator
Pin Logic
Pin Logic
RESET
Comparator
0
P3
RESET
Comparator
LATCH1
P1
LATCH0
Pin Logic
LATCH2
P0
RESET
Comparator
LATCH3
Bus Clock
÷1, 2, ..., 128
Timer
Prescaler
Comparator
EDG6
TC6 Capture/Compare Reg.
MUX
EDG2
Read TC1H
Hold Reg.
SH26
P7
Pin Logic
Comparator
EDG7
EDG3
SH37
TC7 Capture/Compare Reg.
Read TC0H
Hold Reg.
MUX
Figure 7-67. Detailed Timer Block Diagram in Queue Mode when PRNT = 0
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
353
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
÷1, 2, 3, ... 256
Bus Clock
16-Bit Free-Running
16 BITMain
MAIN
TIMER
Timer
Timer
Prescaler
÷ 1, 2, 3, ... 256
16-Bit Load Register
Modulus
Prescaler
16-Bit Modulus
Down Counter
Bus Clock
0
P0
RESET
Comparator
Pin Logic
Delay
Counter
EDG0
TC0 Capture/Compare Reg.
PAC0
TC0H Hold Reg.
PA0H Hold Reg.
0
P1
LATCH0
8, 12, 16, ... 1024
RESET
Comparator
Pin Logic
Delay
Counter
EDG1
TC1 Capture/Compare Reg.
PAC1
TC1H Hold Reg.
PA1H Hold Reg.
0
P2
LATCH1
8, 12, 16, ... 1024
RESET
Comparator
Pin Logic
Delay
Counter
EDG2
TC2 Capture/Compare Reg.
PAC2
TC2H Hold Reg.
PA2H Hold Reg.
0
RESET
Comparator
Pin Logic
Delay
Counter
EDG3
TC3 Capture/Compare Reg.
PAC3
TC3H Hold Reg.
PA3H Hold Reg.
8, 12, 16, ... 1024
P4
Pin Logic
Comparator
EDG4
TC4 Capture/Compare Reg.
LATQ, BUFEN
(Queue Mode)
Comparator
Read TC3H
Hold Reg.
MUX
EDG0
SH04
P5
Pin Logic
EDG5
TC5 Capture/Compare Reg.
MUX
EDG1
Read TC2H
Hold Reg.
SH15
P6
Pin Logic
LATCH3
P3
LATCH2
8, 12, 16, ... 1024
Comparator
EDG6
TC6 Capture/Compare Reg.
MUX
EDG2
Read TC1H
Hold Reg.
SH26
P7
Pin Logic
Comparator
EDG7
EDG3
SH37
TC7 Capture/Compare Reg.
Read TC0H
Hold Reg.
MUX
Figure 7-68. Detailed Timer Block Diagram in Queue Mode when PRNT = 1
MC9S12XDP512 Data Sheet, Rev. 2.21
354
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Load Holding Register and Reset Pulse Accumulator
0
8, 12,16, ..., 1024
8-Bit PAC0 (PACN0)
EDG0
P0
Edge Detector
Delay Counter
PA0H Holding
Register
Interrupt
0
8, 12,16, ..., 1024
EDG1
P1
Edge Detector
8-Bit PAC1 (PACN1)
Delay Counter
PA1H Holding
Register
0
8, 12,16, ..., 1024
EDG2
P2
Edge Detector
8-Bit PAC2 (PACN2)
Delay Counter
PA2H Holding
Register
Interrupt
8, 12,16, ..., 1024
P3
Edge Detector
0
EDG3
8-Bit PAC3 (PACN3)
Delay Counter
PA3H Holding
Register
Figure 7-69. 8-Bit Pulse Accumulators Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
355
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
TIMCLK (Timer Clock)
CLK1
CLK0
PACLK / 256
Clock Select
(PAMOD)
PACLK
PACLK / 65536
Prescaled Clock
(PCLK)
4:1 MUX
Edge Detector
P7
Interrupt
8-Bit PAC3
(PACN3)
8-Bit PAC2
(PACN2)
MUX
PACA
Bus Clock
Divide by 64
Interrupt
8-Bit PAC1
(PACN1)
8-Bit PAC0
(PACN0)
Delay Counter
PACB
Edge Detector
P0
Figure 7-70. 16-Bit Pulse Accumulators Block Diagram
16-Bit Main Timer
Px
Edge
Detector
Delay
Counter
Set CxF
Interrupt
TCx Input
Capture Register
TCxH I.C.
Holding Register
BUFEN • LATQ • TFMOD
Figure 7-71. Block Diagram for Port 7 with Output Compare/Pulse Accumulator A
MC9S12XDP512 Data Sheet, Rev. 2.21
356
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.4.1
Enhanced Capture Timer Modes of Operation
The enhanced capture timer has 8 input capture, output compare (IC/OC) channels, same as on the HC12
standard timer (timer channels TC0 to TC7). When channels are selected as input capture by selecting the
IOSx bit in TIOS register, they are called input capture (IC) channels.
Four IC channels (channels 7–4) are the same as on the standard timer with one capture register each that
memorizes the timer value captured by an action on the associated input pin.
Four other IC channels (channels 3–0), in addition to the capture register, also have one buffer each called
a holding register. This allows two different timer values to be saved without generating any interrupts.
Four 8-bit pulse accumulators are associated with the four buffered IC channels (channels 3–0). Each pulse
accumulator has a holding register to memorize their value by an action on its external input. Each pair of
pulse accumulators can be used as a 16-bit pulse accumulator.
The 16-bit modulus down-counter can control the transfer of the IC registers and the pulse accumulators
contents to the respective holding registers for a given period, every time the count reaches zero.
The modulus down-counter can also be used as a stand-alone time base with periodic interrupt capability.
7.4.1.1
IC Channels
The IC channels are composed of four standard IC registers and four buffered IC channels.
• An IC register is empty when it has been read or latched into the holding register.
• A holding register is empty when it has been read.
7.4.1.1.1
Non-Buffered IC Channels
The main timer value is memorized in the IC register by a valid input pin transition. If the corresponding
NOVWx bit of the ICOVW register is cleared, with a new occurrence of a capture, the contents of IC
register are overwritten by the new value. If the corresponding NOVWx bit of the ICOVW register is set,
the capture register cannot be written unless it is empty. This will prevent the captured value from being
overwritten until it is read.
7.4.1.1.2
Buffered IC Channels
There are two modes of operations for the buffered IC channels:
1. IC latch mode (LATQ = 1)
The main timer value is memorized in the IC register by a valid input pin transition (see Figure 7-65
and Figure 7-66).
The value of the buffered IC register is latched to its holding register by the modulus counter for a
given period when the count reaches zero, by a write 0x0000 to the modulus counter or by a write
to ICLAT in the MCCTL register.
If the corresponding NOVWx bit of the ICOVW register is cleared, with a new occurrence of a
capture, the contents of IC register are overwritten by the new value. In case of latching, the
contents of its holding register are overwritten.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
357
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
If the corresponding NOVWx bit of the ICOVW register is set, the capture register or its holding
register cannot be written by an event unless they are empty (see Section 7.4.1.1, “IC Channels”).
This will prevent the captured value from being overwritten until it is read or latched in the holding
register.
2. IC Queue Mode (LATQ = 0)
The main timer value is memorized in the IC register by a valid input pin transition (see Figure 7-67
and Figure 7-68).
If the corresponding NOVWx bit of the ICOVW register is cleared, with a new occurrence of a
capture, the value of the IC register will be transferred to its holding register and the IC register
memorizes the new timer value.
If the corresponding NOVWx bit of the ICOVW register is set, the capture register or its holding
register cannot be written by an event unless they are empty (see Section 7.4.1.1, “IC Channels”).
In queue mode, reads of the holding register will latch the corresponding pulse accumulator value
to its holding register.
7.4.1.1.3
Delayed IC Channels
There are four delay counters in this module associated with IC channels 0–3. The use of this feature is
explained in the diagram and notes below.
BUS CLOCK
DLY_CNT
0
1
2
3
INPUT ON
CH0–3
255 Cycles
INPUT ON
CH0–3
255.5 Cycles
INPUT ON
CH0–3
255.5 Cycles
INPUT ON
CH0–3
256 Cycles
253
254
255
256
Rejected
Rejected
Accepted
Accepted
Figure 7-72. Channel Input Validity with Delay Counter Feature
In Figure 7-72 a delay counter value of 256 bus cycles is considered.
1. Input pulses with a duration of (DLY_CNT – 1) cycles or shorter are rejected.
2. Input pulses with a duration between (DLY_CNT – 1) and DLY_CNT cycles may be rejected or
accepted, depending on their relative alignment with the sample points.
3. Input pulses with a duration between (DLY_CNT – 1) and DLY_CNT cycles may be rejected or
accepted, depending on their relative alignment with the sample points.
4. Input pulses with a duration of DLY_CNT or longer are accepted.
MC9S12XDP512 Data Sheet, Rev. 2.21
358
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.4.1.2
OC Channel Initialization
Internal register whose output drives OCx when TIOS is set, can be force loaded with a desired data by
writing to CFORC register before OCx is configured for output compare action. This allows a glitch free
switch over of port from general purpose I/O to timer output once the output compare is enabled.
7.4.1.3
Pulse Accumulators
There are four 8-bit pulse accumulators with four 8-bit holding registers associated with the four IC
buffered channels 3–0. A pulse accumulator counts the number of active edges at the input of its channel.
The minimum pulse width for the PAI input is greater than two bus clocks.The maximum input frequency
on the pulse accumulator channel is one half the bus frequency or Eclk.
The user can prevent the 8-bit pulse accumulators from counting further than 0x00FF by utilizing the
PACMX control bit in the ICSYS register. In this case, a value of 0x00FF means that 255 counts or more
have occurred.
Each pair of pulse accumulators can be used as a 16-bit pulse accumulator (see Figure 7-70).
Pulse accumulator B operates only as an event counter, it does not feature gated time accumulation
mode.The edge control for pulse accumulator B as a 16-bit pulse accumulator is defined by TCTL4[1:0].
To operate the 16-bit pulse accumulators A and B (PACA and PACB) 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 or OC7M0 in the OC7M register must also be cleared.
There are two modes of operation for the pulse accumulators:
• Pulse accumulator latch mode
The value of the pulse accumulator is transferred to its holding register when the modulus
down-counter reaches zero, a write 0x0000 to the modulus counter or when the force latch control
bit ICLAT is written.
At the same time the pulse accumulator is cleared.
• Pulse accumulator queue mode
When queue mode is enabled, reads of an input capture holding register will transfer the contents
of the associated pulse accumulator to its holding register.
At the same time the pulse accumulator is cleared.
7.4.1.4
Modulus Down-Counter
The modulus down-counter can be used as a time base to generate a periodic interrupt. It can also be used
to latch the values of the IC registers and the pulse accumulators to their holding registers.
The action of latching can be programmed to be periodic or only once.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
359
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.4.1.5
Precision Timer
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 and modulus down counter
and enhance delay counter settings compared to the settings in the present ECT timer.
7.4.1.6
Flag Clearing Mechanisms
The flags in the ECT can be cleared one of two ways:
1. Normal flag clearing mechanism (TFFCA = 0)
Any of the ECT flags can be cleared by writing a one to the flag.
2. Fast flag clearing mechanism (TFFCA = 1)
With the timer fast flag clear all (TFFCA) enabled, the ECT flags can only be cleared by accessing
the various registers associated with the ECT modes of operation as described below. The flags
cannot be cleared via the normal flag clearing mechanism. This fast flag clearing mechanism has
the advantage of eliminating the software overhead required by a separate clear sequence. Extra
care must be taken to avoid accidental flag clearing due to unintended accesses.
— Input capture
A read from an input capture channel register causes the corresponding channel flag, CxF, to
be cleared in the TFLG1 register.
— Output compare
A write to the output compare channel register causes the corresponding channel flag, CxF, to
be cleared in the TFLG1 register.
— Timer counter
Any access to the TCNT register clears the TOF flag in the TFLG2 register.
— Pulse accumulator A
Any access to the PACN3 and PACN2 registers clears the PAOVF and PAIF flags in the
PAFLG register.
— Pulse accumulator B
Any access to the PACN1 and PACN0 registers clears the PBOVF flag in the PBFLG register.
— Modulus down counter
Any access to the MCCNT register clears the MCZF flag in the MCFLG register.
7.4.2
Reset
The reset state of each individual bit is listed within the register description section (Section 7.3, “Memory
Map and Register Definition”) which details the registers and their bit-fields.
MC9S12XDP512 Data Sheet, Rev. 2.21
360
Freescale Semiconductor
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
7.4.3
Interrupts
This section describes interrupts originated by the ECT block. The MCU must service the interrupt
requests. Table 7-37 lists the interrupts generated by the ECT to communicate with the MCU.
Table 7-37. ECT Interrupts
Interrupt Source
Description
Timer channel 7–0
Active high timer channel interrupts 7–0
Modulus counter underflow
Active high modulus counter interrupt
Pulse accumulator B overflow
Active high pulse accumulator B interrupt
Pulse accumulator A input
Active high pulse accumulator A input interrupt
Pulse accumulator A overflow
Pulse accumulator overflow interrupt
Timer overflow
Timer 0verflow interrupt
The ECT only originates interrupt requests. The following is a description of how the module makes a
request and how the MCU should acknowledge that request. The interrupt vector offset and interrupt
number are chip dependent.
7.4.3.1
Channel [7:0] Interrupt
This active high output will be asserted by the module to request a timer channel 7–0 interrupt to be
serviced by the system controller.
7.4.3.2
Modulus Counter Interrupt
This active high output will be asserted by the module to request a modulus counter underflow interrupt
to be serviced by the system controller.
7.4.3.3
Pulse Accumulator B Overflow Interrupt
This active high output will be asserted by the module to request a timer pulse accumulator B overflow
interrupt to be serviced by the system controller.
7.4.3.4
Pulse Accumulator A Input Interrupt
This active high output will be asserted by the module to request a timer pulse accumulator A input
interrupt to be serviced by the system controller.
7.4.3.5
Pulse Accumulator A Overflow Interrupt
This active high output will be asserted by the module to request a timer pulse accumulator A overflow
interrupt to be serviced by the system controller.
7.4.3.6
Timer Overflow Interrupt
This active high output will be asserted by the module to request a timer overflow interrupt to be serviced
by the system controller.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
361
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
362
Freescale Semiconductor
Chapter 8
Pulse-Width Modulator (S12PWM8B8CV1)
8.1
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.
8.1.1
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
8.1.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
363
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
8.1.3
Block Diagram
Figure 8-1 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
Period and Duty
PWM3
Counter
Channel 2
Polarity
Period and Duty
Alignment
PWM2
Counter
Channel 1
Period and Duty
PWM1
Counter
Channel 0
Period and Duty
Counter
PWM0
Figure 8-1. PWM Block Diagram
8.2
External Signal Description
The PWM module has a total of 8 external pins.
8.2.1
PWM7 — PWM Channel 7
This pin serves as waveform output of PWM channel 7 and as an input for the emergency shutdown
feature.
8.2.2
PWM6 — PWM Channel 6
This pin serves as waveform output of PWM channel 6.
MC9S12XDP512 Data Sheet, Rev. 2.21
364
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
8.2.3
PWM5 — PWM Channel 5
This pin serves as waveform output of PWM channel 5.
8.2.4
PWM4 — PWM Channel 4
This pin serves as waveform output of PWM channel 4.
8.2.5
PWM3 — PWM Channel 3
This pin serves as waveform output of PWM channel 3.
8.2.6
PWM3 — PWM Channel 2
This pin serves as waveform output of PWM channel 2.
8.2.7
PWM3 — PWM Channel 1
This pin serves as waveform output of PWM channel 1.
8.2.8
PWM3 — PWM Channel 0
This pin serves as waveform output of PWM channel 0.
8.3
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.
8.3.1
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
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. .
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
365
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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.
8.3.2
Register Descriptions
This section describes in detail all the registers and register bits in the PWM module.
Register
Name
PWME
R
W
PWMPOL
R
W
PWMCLK
R
W
PWMPRCLK R
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
Bit 7
6
5
4
3
2
1
Bit 0
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
0
0
W
PWMCAE
R
W
PWMCTL
R
W
PWMTST1
R
0
W
PWMPRSC1 R
W
PWMSCLA
R
W
PWMSCLB
R
W
PWMSCNTA R
1
W
PWMSCNTB R
1
W
= Unimplemented or Reserved
Figure 8-2. PWM Register Summary (Sheet 1 of 3)
MC9S12XDP512 Data Sheet, Rev. 2.21
366
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
Register
Name
PWMCNT0
PWMCNT1
PWMCNT2
PWMCNT3
PWMCNT4
PWMCNT5
PWMCNT6
PWMCNT7
PWMPER0
Bit 7
6
5
4
3
2
1
Bit 0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
0
0
0
0
0
0
0
0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
R
W
PWMPER1
R
W
PWMPER2
R
W
PWMPER3
R
W
PWMPER4
R
W
PWMPER5
R
W
PWMPER6
R
W
= Unimplemented or Reserved
Figure 8-2. PWM Register Summary (Sheet 2 of 3)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
367
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
Register
Name
PWMPER7
R
W
PWMDTY0
R
W
PWMDTY1
R
W
PWMDTY2
R
W
PWMDTY3
R
W
PWMDTY4
R
W
PWMDTY5
R
W
PWMDTY6
R
W
PWMDTY7
R
W
PWMSDN
R
W
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
PWMIF
PWMIE
0
PWM7IN
PWM7INL
PWM7ENA
0
PWMRSTRT
PWMLVL
= Unimplemented or Reserved
Figure 8-2. PWM Register Summary (Sheet 3 of 3)
1
Intended for factory test purposes only.
8.3.2.1
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.
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
MC9S12XDP512 Data Sheet, Rev. 2.21
368
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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.
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 8-3. PWM Enable Register (PWME)
Read: Anytime
Write: Anytime
Table 8-1. 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.
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
369
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
8.3.2.2
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.
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 8-4. 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 8-2. PWMPOL Field Descriptions
Field
7–0
PPOL[7:0]
8.3.2.3
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.
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 8-5. PWM Clock Select Register (PWMCLK)
Read: Anytime
Write: Anytime
MC9S12XDP512 Data Sheet, Rev. 2.21
370
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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 8-3. 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.
8.3.2.4
PWM Prescale Clock Select Register (PWMPRCLK)
This register selects the prescale clock source for clocks A and B independently.
7
R
6
0
W
Reset
0
5
4
PCKB2
PCKB1
PCKB0
0
0
0
3
0
0
2
1
0
PCKA2
PCKA1
PCKA0
0
0
0
= Unimplemented or Reserved
Figure 8-6. PWM Prescale Clock Select Register (PWMPRCLK)
Read: Anytime
Write: Anytime
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
371
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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 8-4. 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 8-5.
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 8-6.
s
Table 8-5. 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 8-6. Clock A Prescaler Selects
8.3.2.5
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
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 8.4.2.5, “Left Aligned Outputs” and Section 8.4.2.6, “Center Aligned Outputs” for a more detailed
description of the PWM output modes.
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 8-7. PWM Center Align Enable Register (PWMCAE)
MC9S12XDP512 Data Sheet, Rev. 2.21
372
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
Read: Anytime
Write: Anytime
NOTE
Write these bits only when the corresponding channel is disabled.
Table 8-7. PWMCAE Field Descriptions
Field
7–0
CAE[7:0]
8.3.2.6
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.
7
R
W
Reset
6
CON67
0
5
4
3
2
CON45
CON23
CON01
PSWAI
PFRZ
0
0
0
0
0
1
0
0
0
0
0
= Unimplemented or Reserved
Figure 8-8. 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
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 8.4.2.7, “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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
373
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
Table 8-8. 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.
8.3.2.7
Reserved Register (PWMTST)
This register is reserved for factory testing of the PWM module and is not available in normal modes.
MC9S12XDP512 Data Sheet, Rev. 2.21
374
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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 8-9. 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.
8.3.2.8
Reserved Register (PWMPRSC)
This register is reserved for factory testing of the PWM module and is not available in normal modes.
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 8-10. 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.
8.3.2.9
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)
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).
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
375
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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 8-11. PWM Scale A Register (PWMSCLA)
Read: Anytime
Write: Anytime (causes the scale counter to load the PWMSCLA value)
8.3.2.10
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).
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 8-12. PWM Scale B Register (PWMSCLB)
Read: Anytime
Write: Anytime (causes the scale counter to load the PWMSCLB value).
8.3.2.11
Reserved Registers (PWMSCNTx)
The registers PWMSCNTA and PWMSCNTB are reserved for factory testing of the PWM module and are
not available in normal modes.
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 Registers (PWMSCNTx)
Read: Always read $00 in normal modes
Write: Unimplemented in normal modes
MC9S12XDP512 Data Sheet, Rev. 2.21
376
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
NOTE
Writing to these registers when in special modes can alter the PWM
functionality.
8.3.2.12
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 8.4.2.5, “Left Aligned Outputs” and Section 8.4.2.6, “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 8.4.2.4, “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.
R
7
6
5
4
3
2
1
0
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 8-14. PWM Channel Counter Registers (PWMCNTx)
Read: Anytime
Write: Anytime (any value written causes PWM counter to be reset to $00).
8.3.2.13
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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
377
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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 8.4.2.3, “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 8.4.2.8, “PWM Boundary Cases”.
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 8-15. PWM Channel Period Registers (PWMPERx)
Read: Anytime
Write: Anytime
8.3.2.14
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
378
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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 8.4.2.3, “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 8.4.2.8, “PWM Boundary Cases”.
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 8-16. PWM Channel Duty Registers (PWMDTYx)
Read: Anytime
Write: Anytime
8.3.2.15
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.
7
R
W
Reset
6
5
PWMIF
PWMIE
0
0
0
PWMRSTRT
0
4
PWMLVL
0
3
2
0
PWM7IN
0
0
1
0
PWM7INL
PWM7ENA
0
0
= Unimplemented or Reserved
Figure 8-17. PWM Shutdown Register (PWMSDN)
Read: Anytime
Write: Anytime
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
379
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
Table 8-9. 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.
8.4
8.4.1
Functional Description
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 8-18 shows the four different clocks and how the scaled clocks are created.
MC9S12XDP512 Data Sheet, Rev. 2.21
380
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
8.4.1.1
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.
8.4.1.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
381
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
Clock A
PCKA2
PCKA1
PCKA0
Clock A/2, A/4, A/6,....A/512
8-Bit Down
Counter
Clock to
PWM Ch 0
PCLK0
Count = 1
M
U
X
Load
PWMSCLA
M
U
X
Clock SA
DIV 2
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
U
M
U
X
Clock to
PWM Ch 4
PCLK4
M
Count = 1
8-Bit Down
Counter
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 8-18. PWM Clock Select Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
382
Freescale Semiconductor
Chapter 8 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.
8.4.1.3
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
383
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
8.4.2
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 8-19 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 8-19. PWM Timer Channel Block Diagram
8.4.2.1
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 8.4.2.7, “PWM 16-Bit Functions” for more detail.
NOTE
The first PWM cycle after enabling the channel can be irregular.
MC9S12XDP512 Data Sheet, Rev. 2.21
384
Freescale Semiconductor
Chapter 8 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.
8.4.2.2
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.
8.4.2.3
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.
8.4.2.4
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 8.4.1, “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 8-19. 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 8-19 and described in Section 8.4.2.5, “Left Aligned Outputs”
and Section 8.4.2.6, “Center Aligned Outputs”.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
385
Chapter 8 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
re-enabled. 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 8.4.2.5, “Left Aligned Outputs” and
Section 8.4.2.6, “Center Aligned Outputs” for more details).
Table 8-10. 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
8.4.2.5
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 8-19. 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 8-19, as well as performing a load from the double buffer period and
duty register to the associated registers, as described in Section 8.4.2.3, “PWM Period and Duty”. The
counter counts from 0 to the value in the period register – 1.
MC9S12XDP512 Data Sheet, Rev. 2.21
386
Freescale Semiconductor
Chapter 8 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 8-20. 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 8-21.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
387
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
E = 100 ns
Duty Cycle = 75%
Period = 400 ns
Figure 8-21. PWM Left Aligned Output Example Waveform
8.4.2.6
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 8-19. 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 8.4.2.3, “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 8-22. PWM Center Aligned Output Waveform
MC9S12XDP512 Data Sheet, Rev. 2.21
388
Freescale Semiconductor
Chapter 8 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%
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
389
Chapter 8 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 8-23 is the output waveform generated.
E = 100 ns
E = 100 ns
DUTY CYCLE = 75%
PERIOD = 800 ns
Figure 8-23. PWM Center Aligned Output Example Waveform
8.4.2.7
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 8-24. 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 8-24. The polarity of the resulting PWM output is controlled by the
PPOLx bit of the corresponding low order 8-bit channel as well.
MC9S12XDP512 Data Sheet, Rev. 2.21
390
Freescale Semiconductor
Chapter 8 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 8-24. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
391
Chapter 8 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 8-11 is used to summarize which channels are used to set the various control bits when in 16-bit
mode.
Table 8-11. 16-bit Concatenation Mode Summary
8.4.2.8
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 8-12 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 8-12. PWM Boundary Cases
1
8.5
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
0
Always low
Counter = $00 and does not count.
Resets
The reset state of each individual bit is listed within the Section 8.3.2, “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.
MC9S12XDP512 Data Sheet, Rev. 2.21
392
Freescale Semiconductor
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
8.6
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 8.3.2.15,
“PWM Shutdown Register (PWMSDN)”.
The PWM block only generates the interrupt and does not service it. The interrupt signal name is PWM
interrupt signal.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
393
Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
MC9S12XDP512 Data Sheet, Rev. 2.21
394
Freescale Semiconductor
Chapter 9
Inter-Integrated Circuit (IICV2) Block Description
9.1
Introduction
The inter-IC bus (IIC) is a two-wire, bidirectional serial bus that provides a simple, efficient method of data
exchange between devices. Being a two-wire device, the IIC bus minimizes the need for large numbers of
connections between devices, and eliminates the need for an address decoder.
This bus is suitable for applications requiring occasional communications over a short distance between a
number of devices. It also provides flexibility, allowing additional devices to be connected to the bus for
further expansion and system development.
The interface is designed to operate up to 100 kbps with maximum bus loading and timing. The device is
capable of operating at higher baud rates, up to a maximum of clock/20, with reduced bus loading. The
maximum communication length and the number of devices that can be connected are limited by a
maximum bus capacitance of 400 pF.
9.1.1
Features
The IIC module has the following key features:
• Compatible with I2C bus standard
• Multi-master operation
• Software programmable for one of 256 different serial clock frequencies
• Software selectable acknowledge bit
• Interrupt driven byte-by-byte data transfer
• Arbitration lost interrupt with automatic mode switching from master to slave
• Calling address identification interrupt
• Start and stop signal generation/detection
• Repeated start signal generation
• Acknowledge bit generation/detection
• Bus busy detection
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
395
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
9.1.2
Modes of Operation
The IIC functions the same in normal, special, and emulation modes. It has two low power modes: wait
and stop modes.
9.1.3
Block Diagram
The block diagram of the IIC module is shown in Figure 9-1.
IIC
Registers
Start
Stop
Arbitration
Control
Clock
Control
In/Out
Data
Shift
Register
Interrupt
bus_clock
SCL
SDA
Address
Compare
Figure 9-1. IIC Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
396
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
9.2
External Signal Description
The IICV2 module has two external pins.
9.2.1
IIC_SCL — Serial Clock Line Pin
This is the bidirectional serial clock line (SCL) of the module, compatible to the IIC bus specification.
9.2.2
IIC_SDA — Serial Data Line Pin
This is the bidirectional serial data line (SDA) of the module, compatible to the IIC bus specification.
9.3
Memory Map and Register Definition
This section provides a detailed description of all memory and registers for the IIC module.
9.3.1
Module Memory Map
The memory map for the IIC module is given below in Table 1-1. 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 IIC module and
the address offset for each register.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
397
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
9.3.2
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
IBAD
R
W
IBFD
R
W
IBCR
R
W
IBSR
R
Bit 7
6
5
4
3
2
1
ADR7
ADR6
ADR5
ADR4
ADR3
ADR2
ADR1
IBC7
IBC6
IBC5
IBC4
IBC3
IBC2
IBC1
IBEN
IBIE
MS/SL
Tx/Rx
TXAK
0
0
TCF
IAAS
IBB
D7
D6
D5
IBAL
W
IBDR
R
W
D4
RSTA
0
SRW
D3
D2
IBIF
D1
Bit 0
0
IBC0
IBSWAI
RXAK
D0
= Unimplemented or Reserved
Figure 9-2. IIC Register Summary
9.3.2.1
IIC Address Register (IBAD)
7
6
5
4
3
2
1
ADR7
ADR6
ADR5
ADR4
ADR3
ADR2
ADR1
0
0
0
0
0
0
0
R
0
0
W
Reset
0
= Unimplemented or Reserved
Figure 9-3. IIC Bus Address Register (IBAD)
Read and write anytime
This register contains the address the IIC bus will respond to when addressed as a slave; note that it is not
the address sent on the bus during the address transfer.
Table 9-1. IBAD Field Descriptions
Field
Description
7:1
ADR[7:1]
Slave Address — Bit 1 to bit 7 contain the specific slave address to be used by the IIC bus module.The default
mode of IIC bus is slave mode for an address match on the bus.
0
Reserved
Reserved — Bit 0 of the IBAD is reserved for future compatibility. This bit will always read 0.
MC9S12XDP512 Data Sheet, Rev. 2.21
398
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
9.3.2.2
IIC Frequency Divider Register (IBFD)
7
6
5
4
3
2
1
0
IBC7
IBC6
IBC5
IBC4
IBC3
IBC2
IBC1
IBC0
0
0
0
0
0
0
0
0
R
W
Reset
= Unimplemented or Reserved
Figure 9-4. IIC Bus Frequency Divider Register (IBFD)
Read and write anytime
Table 9-2. IBFD Field Descriptions
Field
Description
7:0
IBC[7:0]
I Bus Clock Rate 7:0 — This field is used to prescale the clock for bit rate selection. The bit clock generator is
implemented as a prescale divider — IBC7:6, prescaled shift register — IBC5:3 select the prescaler divider and
IBC2-0 select the shift register tap point. The IBC bits are decoded to give the tap and prescale values as shown
in Table 9-3.
Table 9-3. I-Bus Tap and Prescale Values
IBC2-0
(bin)
SCL Tap
(clocks)
SDA Tap
(clocks)
000
5
1
001
6
1
010
7
2
011
8
2
100
9
3
101
10
3
110
12
4
111
15
4
IBC5-3
(bin)
scl2start
(clocks)
scl2stop
(clocks)
scl2tap
(clocks)
tap2tap
(clocks)
000
2
7
4
1
001
2
7
4
2
010
2
9
6
4
011
6
9
6
8
100
14
17
14
16
101
30
33
30
32
110
62
65
62
64
111
126
129
126
128
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
399
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
Table 9-4. Multiplier Factor
IBC7-6
MUL
00
01
01
02
10
04
11
RESERVED
The number of clocks from the falling edge of SCL to the first tap (Tap[1]) is defined by the values shown
in the scl2tap column of Table 9-3, all subsequent tap points are separated by 2IBC5-3 as shown in the
tap2tap column in Table 9-3. The SCL Tap is used to generated the SCL period and the SDA Tap is used
to determine the delay from the falling edge of SCL to SDA changing, the SDA hold time.
IBC7–6 defines the multiplier factor MUL. The values of MUL are shown in the Table 9-4.
SCL Divider
SCL
SDA Hold
SDA
SDA
SCL Hold(stop)
SCL Hold(start)
SCL
START condition
STOP condition
Figure 9-5. SCL Divider and SDA Hold
The equation used to generate the divider values from the IBFD bits is:
SCL Divider = MUL x {2 x (scl2tap + [(SCL_Tap -1) x tap2tap] + 2)}
MC9S12XDP512 Data Sheet, Rev. 2.21
400
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
The SDA hold delay is equal to the CPU clock period multiplied by the SDA Hold value shown in
Table 9-5. The equation used to generate the SDA Hold value from the IBFD bits is:
SDA Hold = MUL x {scl2tap + [(SDA_Tap - 1) x tap2tap] + 3}
The equation for SCL Hold values to generate the start and stop conditions from the IBFD bits is:
SCL Hold(start) = MUL x [scl2start + (SCL_Tap - 1) x tap2tap]
SCL Hold(stop) = MUL x [scl2stop + (SCL_Tap - 1) x tap2tap]
Table 9-5. IIC Divider and Hold Values (Sheet 1 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
20
22
24
26
28
30
34
40
28
32
36
40
44
48
56
68
48
56
64
72
80
88
104
128
80
96
112
128
144
160
192
240
160
192
224
7
7
8
8
9
9
10
10
7
7
9
9
11
11
13
13
9
9
13
13
17
17
21
21
9
9
17
17
25
25
33
33
17
17
33
6
7
8
9
10
11
13
16
10
12
14
16
18
20
24
30
18
22
26
30
34
38
46
58
38
46
54
62
70
78
94
118
78
94
110
11
12
13
14
15
16
18
21
15
17
19
21
23
25
29
35
25
29
33
37
41
45
53
65
41
49
57
65
73
81
97
121
81
97
113
MUL=1
00
01
02
03
04
05
06
07
08
09
0A
0B
0C
0D
0E
0F
10
11
12
13
14
15
16
17
18
19
1A
1B
1C
1D
1E
1F
20
21
22
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
401
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
Table 9-5. IIC Divider and Hold Values (Sheet 2 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
23
24
25
26
27
28
29
2A
2B
2C
2D
2E
2F
30
31
32
33
34
35
36
37
38
39
3A
3B
3C
3D
3E
3F
256
288
320
384
480
320
384
448
512
576
640
768
960
640
768
896
1024
1152
1280
1536
1920
1280
1536
1792
2048
2304
2560
3072
3840
33
49
49
65
65
33
33
65
65
97
97
129
129
65
65
129
129
193
193
257
257
129
129
257
257
385
385
513
513
126
142
158
190
238
158
190
222
254
286
318
382
478
318
382
446
510
574
638
766
958
638
766
894
1022
1150
1278
1534
1918
129
145
161
193
241
161
193
225
257
289
321
385
481
321
385
449
513
577
641
769
961
641
769
897
1025
1153
1281
1537
1921
40
41
42
43
44
45
46
47
48
49
4A
4B
4C
4D
4E
40
44
48
52
56
60
68
80
56
64
72
80
88
96
112
14
14
16
16
18
18
20
20
14
14
18
18
22
22
26
12
14
16
18
20
22
26
32
20
24
28
32
36
40
48
22
24
26
28
30
32
36
42
30
34
38
42
46
50
58
MUL=2
MC9S12XDP512 Data Sheet, Rev. 2.21
402
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
Table 9-5. IIC Divider and Hold Values (Sheet 3 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
4F
50
51
52
53
54
55
56
57
58
59
5A
5B
5C
5D
5E
5F
60
61
62
63
64
65
66
67
68
69
6A
6B
6C
6D
6E
6F
70
71
72
73
74
75
76
77
78
79
7A
7B
136
96
112
128
144
160
176
208
256
160
192
224
256
288
320
384
480
320
384
448
512
576
640
768
960
640
768
896
1024
1152
1280
1536
1920
1280
1536
1792
2048
2304
2560
3072
3840
2560
3072
3584
4096
26
18
18
26
26
34
34
42
42
18
18
34
34
50
50
66
66
34
34
66
66
98
98
130
130
66
66
130
130
194
194
258
258
130
130
258
258
386
386
514
514
258
258
514
514
60
36
44
52
60
68
76
92
116
76
92
108
124
140
156
188
236
156
188
220
252
284
316
380
476
316
380
444
508
572
636
764
956
636
764
892
1020
1148
1276
1532
1916
1276
1532
1788
2044
70
50
58
66
74
82
90
106
130
82
98
114
130
146
162
194
242
162
194
226
258
290
322
386
482
322
386
450
514
578
642
770
962
642
770
898
1026
1154
1282
1538
1922
1282
1538
1794
2050
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
403
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
Table 9-5. IIC Divider and Hold Values (Sheet 4 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
7C
7D
7E
7F
4608
5120
6144
7680
770
770
1026
1026
2300
2556
3068
3836
2306
2562
3074
3842
80
81
82
83
84
85
86
87
88
89
8A
8B
8C
8D
8E
8F
90
91
92
93
94
95
96
97
98
99
9A
9B
9C
9D
9E
9F
A0
A1
A2
A3
A4
A5
A6
A7
80
88
96
104
112
120
136
160
112
128
144
160
176
192
224
272
192
224
256
288
320
352
416
512
320
384
448
512
576
640
768
960
640
768
896
1024
1152
1280
1536
1920
28
28
32
32
36
36
40
40
28
28
36
36
44
44
52
52
36
36
52
52
68
68
84
84
36
36
68
68
100
100
132
132
68
68
132
132
196
196
260
260
24
28
32
36
40
44
52
64
40
48
56
64
72
80
96
120
72
88
104
120
136
152
184
232
152
184
216
248
280
312
376
472
312
376
440
504
568
632
760
952
44
48
52
56
60
64
72
84
60
68
76
84
92
100
116
140
100
116
132
148
164
180
212
260
164
196
228
260
292
324
388
484
324
388
452
516
580
644
772
964
MUL=4
MC9S12XDP512 Data Sheet, Rev. 2.21
404
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
Table 9-5. IIC Divider and Hold Values (Sheet 5 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
A8
A9
AA
AB
AC
AD
AE
AF
B0
B1
B2
B3
B4
B5
B6
B7
B8
B9
BA
BB
BC
BD
BE
BF
1280
1536
1792
2048
2304
2560
3072
3840
2560
3072
3584
4096
4608
5120
6144
7680
5120
6144
7168
8192
9216
10240
12288
15360
132
132
260
260
388
388
516
516
260
260
516
516
772
772
1028
1028
516
516
1028
1028
1540
1540
2052
2052
632
760
888
1016
1144
1272
1528
1912
1272
1528
1784
2040
2296
2552
3064
3832
2552
3064
3576
4088
4600
5112
6136
7672
644
772
900
1028
1156
1284
1540
1924
1284
1540
1796
2052
2308
2564
3076
3844
2564
3076
3588
4100
4612
5124
6148
7684
9.3.2.3
IIC Control Register (IBCR)
7
6
5
4
3
IBEN
IBIE
MS/SL
Tx/Rx
TXAK
R
1
0
0
0
IBSWAI
RSTA
W
Reset
2
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 9-6. IIC Bus Control Register (IBCR)
Read and write anytime
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
405
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
Table 9-6. IBCR Field Descriptions
Field
Description
7
IBEN
I-Bus Enable — This bit controls the software reset of the entire IIC bus module.
0 The module is reset and disabled. This is the power-on reset situation. When low the interface is held in reset
but registers can be accessed
1 The IIC bus module is enabled.This bit must be set before any other IBCR bits have any effect
If the IIC bus module is enabled in the middle of a byte transfer the interface behaves as follows: slave mode
ignores the current transfer on the bus and starts operating whenever a subsequent start condition is detected.
Master mode will not be aware that the bus is busy, hence if a start cycle is initiated then the current bus cycle
may become corrupt. This would ultimately result in either the current bus master or the IIC bus module losing
arbitration, after which bus operation would return to normal.
6
IBIE
I-Bus Interrupt Enable
0 Interrupts from the IIC bus module are disabled. Note that this does not clear any currently pending interrupt
condition
1 Interrupts from the IIC bus module are enabled. An IIC bus interrupt occurs provided the IBIF bit in the status
register is also set.
5
MS/SL
Master/Slave Mode Select Bit — Upon reset, this bit is cleared. When this bit is changed from 0 to 1, a START
signal is generated on the bus, and the master mode is selected. When this bit is changed from 1 to 0, a STOP
signal is generated and the operation mode changes from master to slave.A STOP signal should only be
generated if the IBIF flag is set. MS/SL is cleared without generating a STOP signal when the master loses
arbitration.
0 Slave Mode
1 Master Mode
4
Tx/Rx
Transmit/Receive Mode Select Bit — This bit selects the direction of master and slave transfers. When
addressed as a slave this bit should be set by software according to the SRW bit in the status register. In master
mode this bit should be set according to the type of transfer required. Therefore, for address cycles, this bit will
always be high.
0 Receive
1 Transmit
3
TXAK
Transmit Acknowledge Enable — This bit specifies the value driven onto SDA during data acknowledge cycles
for both master and slave receivers. The IIC module will always acknowledge address matches, provided it is
enabled, regardless of the value of TXAK. Note that values written to this bit are only used when the IIC bus is a
receiver, not a transmitter.
0 An acknowledge signal will be sent out to the bus at the 9th clock bit after receiving one byte data
1 No acknowledge signal response is sent (i.e., acknowledge bit = 1)
2
RSTA
Repeat Start — Writing a 1 to this bit will generate a repeated START condition on the bus, provided it is the
current bus master. This bit will always be read as a low. Attempting a repeated start at the wrong time, if the bus
is owned by another master, will result in loss of arbitration.
1 Generate repeat start cycle
1
Reserved — Bit 1 of the IBCR is reserved for future compatibility. This bit will always read 0.
RESERVED
0
IBSWAI
I Bus Interface Stop in Wait Mode
0 IIC bus module clock operates normally
1 Halt IIC bus module clock generation in wait mode
Wait mode is entered via execution of a CPU WAI instruction. In the event that the IBSWAI bit is set, all
clocks internal to the IIC will be stopped and any transmission currently in progress will halt.If the CPU
were woken up by a source other than the IIC module, then clocks would restart and the IIC would resume
MC9S12XDP512 Data Sheet, Rev. 2.21
406
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
from where was during the previous transmission. It is not possible for the IIC to wake up the CPU when
its internal clocks are stopped.
If it were the case that the IBSWAI bit was cleared when the WAI instruction was executed, the IIC internal
clocks and interface would remain alive, continuing the operation which was currently underway. It is also
possible to configure the IIC such that it will wake up the CPU via an interrupt at the conclusion of the
current operation. See the discussion on the IBIF and IBIE bits in the IBSR and IBCR, respectively.
9.3.2.4
R
IIC Status Register (IBSR)
7
6
5
TCF
IAAS
IBB
4
3
2
0
SRW
IBAL
1
0
RXAK
IBIF
W
Reset
1
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 9-7. IIC Bus Status Register (IBSR)
This status register is read-only with exception of bit 1 (IBIF) and bit 4 (IBAL), which are software
clearable.
Table 9-7. IBSR Field Descriptions
Field
Description
7
TCF
Data Transferring Bit — While one byte of data is being transferred, this bit is cleared. It is set by the falling
edge of the 9th clock of a byte transfer. Note that this bit is only valid during or immediately following a transfer
to the IIC module or from the IIC module.
0 Transfer in progress
1 Transfer complete
6
IAAS
Addressed as a Slave Bit — When its own specific address (I-bus address register) is matched with the calling
address, this bit is set.The CPU is interrupted provided the IBIE is set.Then the CPU needs to check the SRW
bit and set its Tx/Rx mode accordingly.Writing to the I-bus control register clears this bit.
0 Not addressed
1 Addressed as a slave
5
IBB
Bus Busy Bit
0 This bit indicates the status of the bus. When a START signal is detected, the IBB is set. If a STOP signal is
detected, IBB is cleared and the bus enters idle state.
1 Bus is busy
4
IBAL
Arbitration Lost — The arbitration lost bit (IBAL) is set by hardware when the arbitration procedure is lost.
Arbitration is lost in the following circumstances:
1. SDA sampled low when the master drives a high during an address or data transmit cycle.
2. SDA sampled low when the master drives a high during the acknowledge bit of a data receive cycle.
3. A start cycle is attempted when the bus is busy.
4. A repeated start cycle is requested in slave mode.
5. A stop condition is detected when the master did not request it.
This bit must be cleared by software, by writing a one to it. A write of 0 has no effect on this bit.
3
Reserved — Bit 3 of IBSR is reserved for future use. A read operation on this bit will return 0.
RESERVED
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
407
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
Table 9-7. IBSR Field Descriptions (continued)
Field
Description
2
SRW
Slave Read/Write — When IAAS is set this bit indicates the value of the R/W command bit of the calling address
sent from the master
This bit is only valid when the I-bus is in slave mode, a complete address transfer has occurred with an address
match and no other transfers have been initiated.
Checking this bit, the CPU can select slave transmit/receive mode according to the command of the master.
0 Slave receive, master writing to slave
1 Slave transmit, master reading from slave
1
IBIF
I-Bus Interrupt — The IBIF bit is set when one of the following conditions occurs:
— Arbitration lost (IBAL bit set)
— Byte transfer complete (TCF bit set)
— Addressed as slave (IAAS bit set)
It will cause a processor interrupt request if the IBIE bit is set. This bit must be cleared by software, writing a one
to it. A write of 0 has no effect on this bit.
0
RXAK
Received Acknowledge — The value of SDA during the acknowledge bit of a bus cycle. If the received
acknowledge bit (RXAK) is low, it indicates an acknowledge signal has been received after the completion of 8
bits data transmission on the bus. If RXAK is high, it means no acknowledge signal is detected at the 9th clock.
0 Acknowledge received
1 No acknowledge received
9.3.2.5
IIC Data I/O Register (IBDR)
7
6
5
4
3
2
1
0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
0
R
W
Reset
Figure 9-8. IIC Bus Data I/O Register (IBDR)
In master transmit mode, when data is written to the IBDR a data transfer is initiated. The most significant
bit is sent first. In master receive mode, reading this register initiates next byte data receiving. In slave
mode, the same functions are available after an address match has occurred.Note that the Tx/Rx bit in the
IBCR must correctly reflect the desired direction of transfer in master and slave modes for the transmission
to begin. For instance, if the IIC is configured for master transmit but a master receive is desired, then
reading the IBDR will not initiate the receive.
Reading the IBDR will return the last byte received while the IIC is configured in either master receive or
slave receive modes. The IBDR does not reflect every byte that is transmitted on the IIC bus, nor can
software verify that a byte has been written to the IBDR correctly by reading it back.
In master transmit mode, the first byte of data written to IBDR following assertion of MS/SL is used for
the address transfer and should com.prise of the calling address (in position D7:D1) concatenated with the
required R/W bit (in position D0).
MC9S12XDP512 Data Sheet, Rev. 2.21
408
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
9.4
Functional Description
This section provides a complete functional description of the IICV2.
9.4.1
I-Bus Protocol
The IIC bus system uses a serial data line (SDA) and a serial clock line (SCL) for data transfer. All devices
connected to it must have open drain or open collector outputs. Logic AND function is exercised on both
lines with external pull-up resistors. The value of these resistors is system dependent.
Normally, a standard communication is composed of four parts: START signal, slave address transmission,
data transfer and STOP signal. They are described briefly in the following sections and illustrated in
Figure 9-9.
MSB
SCL
SDA
1
LSB
2
3
4
5
6
7
Calling Address
Read/
Write
MSB
SDA
MSB
9
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
Start
Signal
SCL
8
1
XXX
3
4
5
6
7
8
Calling Address
Read/
Write
3
4
5
6
7
8
D7
D6
D5
D4
D3
D2
D1
D0
Data Byte
1
XX
Ack
Bit
9
No Stop
Ack Signal
Bit
MSB
9
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
Start
Signal
2
Ack
Bit
LSB
2
LSB
1
LSB
2
3
4
5
6
7
8
9
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
Repeated
Start
Signal
New Calling Address
Read/
Write
No Stop
Ack Signal
Bit
Figure 9-9. IIC-Bus Transmission Signals
9.4.1.1
START Signal
When the bus is free, i.e. no master device is engaging the bus (both SCL and SDA lines are at logical
high), a master may initiate communication by sending a START signal.As shown in Figure 9-9, a START
signal is defined as a high-to-low transition of SDA while SCL is high. This signal denotes the beginning
of a new data transfer (each data transfer may contain several bytes of data) and brings all slaves out of
their idle states.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
409
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
SDA
SCL
START Condition
STOP Condition
Figure 9-10. Start and Stop Conditions
9.4.1.2
Slave Address Transmission
The first byte of data transfer immediately after the START signal is the slave address transmitted by the
master. This is a seven-bit calling address followed by a R/W bit. The R/W bit tells the slave the desired
direction of data transfer.
1 = Read transfer, the slave transmits data to the master.
0 = Write transfer, the master transmits data to the slave.
Only the slave with a calling address that matches the one transmitted by the master will respond by
sending back an acknowledge bit. This is done by pulling the SDA low at the 9th clock (see Figure 9-9).
No two slaves in the system may have the same address. If the IIC bus is master, it must not transmit an
address that is equal to its own slave address. The IIC bus cannot be master and slave at the same
time.However, if arbitration is lost during an address cycle the IIC bus will revert to slave mode and operate
correctly even if it is being addressed by another master.
9.4.1.3
Data Transfer
As soon as successful slave addressing is achieved, the data transfer can proceed byte-by-byte in a
direction specified by the R/W bit sent by the calling master
All transfers that come after an address cycle are referred to as data transfers, even if they carry sub-address
information for the slave device.
Each data byte is 8 bits long. Data may be changed only while SCL is low and must be held stable while
SCL is high as shown in Figure 9-9. There is one clock pulse on SCL for each data bit, the MSB being
transferred first. Each data byte has to be followed by an acknowledge bit, which is signalled from the
receiving device by pulling the SDA low at the ninth clock. So one complete data byte transfer needs nine
clock pulses.
If the slave receiver does not acknowledge the master, the SDA line must be left high by the slave. The
master can then generate a stop signal to abort the data transfer or a start signal (repeated start) to
commence a new calling.
MC9S12XDP512 Data Sheet, Rev. 2.21
410
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
If the master receiver does not acknowledge the slave transmitter after a byte transmission, it means 'end
of data' to the slave, so the slave releases the SDA line for the master to generate STOP or START signal.
9.4.1.4
STOP Signal
The master can terminate the communication by generating a STOP signal to free the bus. However, the
master may generate a START signal followed by a calling command without generating a STOP signal
first. This is called repeated START. A STOP signal is defined as a low-to-high transition of SDA while
SCL at logical 1 (see Figure 9-9).
The master can generate a STOP even if the slave has generated an acknowledge at which point the slave
must release the bus.
9.4.1.5
Repeated START Signal
As shown in Figure 9-9, a repeated START signal is a START signal generated without first generating a
STOP signal to terminate the communication. This is used by the master to communicate with another
slave or with the same slave in different mode (transmit/receive mode) without releasing the bus.
9.4.1.6
Arbitration Procedure
The Inter-IC bus is a true multi-master bus that allows more than one master to be connected on it. If two
or more masters try to control the bus at the same time, a clock synchronization procedure determines the
bus clock, for which the low period is equal to the longest clock low period and the high is equal to the
shortest one among the masters. The relative priority of the contending masters is determined by a data
arbitration procedure, a bus master loses arbitration if it transmits logic 1 while another master transmits
logic 0. The losing masters immediately switch over to slave receive mode and stop driving SDA output.
In this case the transition from master to slave mode does not generate a STOP condition. Meanwhile, a
status bit is set by hardware to indicate loss of arbitration.
9.4.1.7
Clock Synchronization
Because wire-AND logic is performed on SCL line, a high-to-low transition on SCL line affects all the
devices connected on the bus. The devices start counting their low period and as soon as a device's clock
has gone low, it holds the SCL line low until the clock high state is reached.However, the change of low to
high in this device clock may not change the state of the SCL line if another device clock is within its low
period. Therefore, synchronized clock SCL is held low by the device with the longest low period. Devices
with shorter low periods enter a high wait state during this time (see Figure 9-10). When all devices
concerned have counted off their low period, the synchronized clock SCL line is released and pulled high.
There is then no difference between the device clocks and the state of the SCL line and all the devices start
counting their high periods.The first device to complete its high period pulls the SCL line low again.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
411
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
WAIT
Start Counting High Period
SCL1
SCL2
SCL
Internal Counter Reset
Figure 9-11. IIC-Bus Clock Synchronization
9.4.1.8
Handshaking
The clock synchronization mechanism can be used as a handshake in data transfer. Slave devices may hold
the SCL low after completion of one byte transfer (9 bits). In such case, it halts the bus clock and forces
the master clock into wait states until the slave releases the SCL line.
9.4.1.9
Clock Stretching
The clock synchronization mechanism can be used by slaves to slow down the bit rate of a transfer. After
the master has driven SCL low the slave can drive SCL low for the required period and then release it.If
the slave SCL low period is greater than the master SCL low period then the resulting SCL bus signal low
period is stretched.
9.4.2
Operation in Run Mode
This is the basic mode of operation.
9.4.3
Operation in Wait Mode
IIC operation in wait mode can be configured. Depending on the state of internal bits, the IIC can operate
normally when the CPU is in wait mode or the IIC clock generation can be turned off and the IIC module
enters a power conservation state during wait mode. In the later case, any transmission or reception in
progress stops at wait mode entry.
9.4.4
Operation in Stop Mode
The IIC is inactive in stop mode for reduced power consumption. The STOP instruction does not affect IIC
register states.
MC9S12XDP512 Data Sheet, Rev. 2.21
412
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
9.5
Resets
The reset state of each individual bit is listed in Section 9.3, “Memory Map and Register Definition,” which
details the registers and their bit-fields.
9.6
Interrupts
IICV2 uses only one interrupt vector.
Table 9-8. Interrupt Summary
Interrupt
Offset
Vector
Priority
IIC
Interrupt
—
—
—
Source
Description
IBAL, TCF, IAAS When either of IBAL, TCF or IAAS bits is set
bits in IBSR
may cause an interrupt based on arbitration
register
lost, transfer complete or address detect
conditions
Internally there are three types of interrupts in IIC. The interrupt service routine can determine the interrupt
type by reading the status register.
IIC Interrupt can be generated on
1. Arbitration lost condition (IBAL bit set)
2. Byte transfer condition (TCF bit set)
3. Address detect condition (IAAS bit set)
The IIC interrupt is enabled by the IBIE bit in the IIC control register. It must be cleared by writing 0 to
the IBF bit in the interrupt service routine.
9.7
9.7.1
9.7.1.1
Initialization/Application Information
IIC Programming Examples
Initialization Sequence
Reset will put the IIC bus control register to its default status. Before the interface can be used to transfer
serial data, an initialization procedure must be carried out, as follows:
1. Update the frequency divider register (IBFD) and select the required division ratio to obtain SCL
frequency from system clock.
2. Update the IIC bus address register (IBAD) to define its slave address.
3. Set the IBEN bit of the IIC bus control register (IBCR) to enable the IIC interface system.
4. Modify the bits of the IIC bus control register (IBCR) to select master/slave mode, transmit/receive
mode and interrupt enable or not.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
413
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
9.7.1.2
Generation of START
After completion of the initialization procedure, serial data can be transmitted by selecting the 'master
transmitter' mode. If the device is connected to a multi-master bus system, the state of the IIC bus busy bit
(IBB) must be tested to check whether the serial bus is free.
If the bus is free (IBB=0), the start condition and the first byte (the slave address) can be sent. The data
written to the data register comprises the slave calling address and the LSB set to indicate the direction of
transfer required from the slave.
The bus free time (i.e., the time between a STOP condition and the following START condition) is built
into the hardware that generates the START cycle. Depending on the relative frequencies of the system
clock and the SCL period it may be necessary to wait until the IIC is busy after writing the calling address
to the IBDR before proceeding with the following instructions. This is illustrated in the following example.
An example of a program which generates the START signal and transmits the first byte of data (slave
address) is shown below:
CHFLAG
BRSET
IBSR,#$20,*
;WAIT FOR IBB FLAG TO CLEAR
TXSTART
BSET
IBCR,#$30
;SET TRANSMIT AND MASTER MODE;i.e. GENERATE START CONDITION
MOVB
CALLING,IBDR
;TRANSMIT THE CALLING ADDRESS, D0=R/W
BRCLR
IBSR,#$20,*
;WAIT FOR IBB FLAG TO SET
IBFREE
9.7.1.3
Post-Transfer Software Response
Transmission or reception of a byte will set the data transferring bit (TCF) to 1, which indicates one byte
communication is finished. The IIC bus interrupt bit (IBIF) is set also; an interrupt will be generated if the
interrupt function is enabled during initialization by setting the IBIE bit. Software must clear the IBIF bit
in the interrupt routine first. The TCF bit will be cleared by reading from the IIC bus data I/O register
(IBDR) in receive mode or writing to IBDR in transmit mode.
Software may service the IIC I/O in the main program by monitoring the IBIF bit if the interrupt function
is disabled. Note that polling should monitor the IBIF bit rather than the TCF bit because their operation
is different when arbitration is lost.
Note that when an interrupt occurs at the end of the address cycle the master will always be in transmit
mode, i.e. the address is transmitted. If master receive mode is required, indicated by R/W bit in IBDR,
then the Tx/Rx bit should be toggled at this stage.
During slave mode address cycles (IAAS=1), the SRW bit in the status register is read to determine the
direction of the subsequent transfer and the Tx/Rx bit is programmed accordingly. For slave mode data
cycles (IAAS=0) the SRW bit is not valid, the Tx/Rx bit in the control register should be read to determine
the direction of the current transfer.
The following is an example of a software response by a 'master transmitter' in the interrupt routine.
ISR
TRANSMIT
BCLR
BRCLR
BRCLR
BRSET
MOVB
IBSR,#$02
IBCR,#$20,SLAVE
IBCR,#$10,RECEIVE
IBSR,#$01,END
DATABUF,IBDR
;CLEAR THE IBIF FLAG
;BRANCH IF IN SLAVE MODE
;BRANCH IF IN RECEIVE MODE
;IF NO ACK, END OF TRANSMISSION
;TRANSMIT NEXT BYTE OF DATA
MC9S12XDP512 Data Sheet, Rev. 2.21
414
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
9.7.1.4
Generation of STOP
A data transfer ends with a STOP signal generated by the 'master' device. A master transmitter can simply
generate a STOP signal after all the data has been transmitted. The following is an example showing how
a stop condition is generated by a master transmitter.
MASTX
END
EMASTX
TST
BEQ
BRSET
MOVB
DEC
BRA
BCLR
RTI
TXCNT
END
IBSR,#$01,END
DATABUF,IBDR
TXCNT
EMASTX
IBCR,#$20
;GET VALUE FROM THE TRANSMITING COUNTER
;END IF NO MORE DATA
;END IF NO ACK
;TRANSMIT NEXT BYTE OF DATA
;DECREASE THE TXCNT
;EXIT
;GENERATE A STOP CONDITION
;RETURN FROM INTERRUPT
If a master receiver wants to terminate a data transfer, it must inform the slave transmitter by not
acknowledging the last byte of data which can be done by setting the transmit acknowledge bit (TXAK)
before reading the 2nd last byte of data. Before reading the last byte of data, a STOP signal must be
generated first. The following is an example showing how a STOP signal is generated by a master receiver.
MASR
DEC
BEQ
MOVB
DEC
BNE
BSET
RXCNT
ENMASR
RXCNT,D1
D1
NXMAR
IBCR,#$08
ENMASR
NXMAR
BRA
BCLR
MOVB
RTI
NXMAR
IBCR,#$20
IBDR,RXBUF
9.7.1.5
Generation of Repeated START
LAMAR
;DECREASE THE RXCNT
;LAST BYTE TO BE READ
;CHECK SECOND LAST BYTE
;TO BE READ
;NOT LAST OR SECOND LAST
;SECOND LAST, DISABLE ACK
;TRANSMITTING
;LAST ONE, GENERATE ‘STOP’ SIGNAL
;READ DATA AND STORE
At the end of data transfer, if the master continues to want to communicate on the bus, it can generate
another START signal followed by another slave address without first generating a STOP signal. A
program example is as shown.
RESTART
BSET
MOVB
IBCR,#$04
CALLING,IBDR
9.7.1.6
Slave Mode
;ANOTHER START (RESTART)
;TRANSMIT THE CALLING ADDRESS;D0=R/W
In the slave interrupt service routine, the module addressed as slave bit (IAAS) should be tested to check
if a calling of its own address has just been received. If IAAS is set, software should set the transmit/receive
mode select bit (Tx/Rx bit of IBCR) according to the R/W command bit (SRW). Writing to the IBCR
clears the IAAS automatically. Note that the only time IAAS is read as set is from the interrupt at the end
of the address cycle where an address match occurred, interrupts resulting from subsequent data transfers
will have IAAS cleared. A data transfer may now be initiated by writing information to IBDR, for slave
transmits, or dummy reading from IBDR, in slave receive mode. The slave will drive SCL low in-between
byte transfers, SCL is released when the IBDR is accessed in the required mode.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
415
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
In slave transmitter routine, the received acknowledge bit (RXAK) must be tested before transmitting the
next byte of data. Setting RXAK means an 'end of data' signal from the master receiver, after which it must
be switched from transmitter mode to receiver mode by software. A dummy read then releases the SCL
line so that the master can generate a STOP signal.
9.7.1.7
Arbitration Lost
If several masters try to engage the bus simultaneously, only one master wins and the others lose
arbitration. The devices which lost arbitration are immediately switched to slave receive mode by the
hardware. Their data output to the SDA line is stopped, but SCL continues to be generated until the end of
the byte during which arbitration was lost. An interrupt occurs at the falling edge of the ninth clock of this
transfer with IBAL=1 and MS/SL=0. If one master attempts to start transmission while the bus is being
engaged by another master, the hardware will inhibit the transmission; switch the MS/SL bit from 1 to 0
without generating STOP condition; generate an interrupt to CPU and set the IBAL to indicate that the
attempt to engage the bus is failed. When considering these cases, the slave service routine should test the
IBAL first and the software should clear the IBAL bit if it is set.
MC9S12XDP512 Data Sheet, Rev. 2.21
416
Freescale Semiconductor
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
Clear
IBIF
Master
Mode
?
Y
TX
N
Arbitration
Lost
?
Y
RX
Tx/Rx
?
N
Last Byte
Transmitted
?
N
Clear IBAL
Y
RXAK=0
?
N
Last
Byte To Be Read
?
N
Y
N
Y
Y
IAAS=1
?
IAAS=1
?
Y
N
Address Transfer
End Of
Addr Cycle
(Master Rx)
?
N
Y
Y
(Read)
2nd Last
Y
Byte To Be Read
?
SRW=1
?
Write Next
Byte To IBDR
Generate
Stop Signal
Set TXAK =1
Generate
Stop Signal
Read Data
From IBDR
And Store
ACK From
Receiver
?
N
Read Data
From IBDR
And Store
Tx Next
Byte
Set RX
Mode
Switch To
Rx Mode
Dummy Read
From IBDR
Dummy Read
From IBDR
Switch To
Rx Mode
RX
TX
Y
Set TX
Mode
Write Data
To IBDR
Dummy Read
From IBDR
TX/RX
?
N (Write)
N
Data Transfer
RTI
Figure 9-12. Flow-Chart of Typical IIC Interrupt Routine
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
417
Chapter 9 Inter-Integrated Circuit (IICV2) Block Description
MC9S12XDP512 Data Sheet, Rev. 2.21
418
Freescale Semiconductor
Chapter 10
Freescale’s Scalable Controller Area Network
(S12MSCANV3)
10.1
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.
10.1.1
Glossary
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: Direct clock from external oscillator
bus clock: CPU bus realated clock
CAN clock: CAN protocol related clock
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
419
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.1.2
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 10-1. MSCAN Block Diagram
10.1.3
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 wakeup 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
1. Depending on the actual bit timing and the clock jitter of the PLL.
MC9S12XDP512 Data Sheet, Rev. 2.21
420
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
•
•
•
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
10.1.4
Modes of Operation
The following modes of operation are specific to the MSCAN. See Section 10.4, “Functional Description,”
for details.
• Listen-Only Mode
• MSCAN Sleep Mode
• MSCAN Initialization Mode
• MSCAN Power Down Mode
10.2
External Signal Description
The MSCAN uses two external pins:
10.2.1
RXCAN — CAN Receiver Input Pin
RXCAN is the MSCAN receiver input pin.
10.2.2
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
10.2.3
CAN System
A typical CAN system with MSCAN is shown in Figure 10-2. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
421
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
CAN node 2
CAN node 1
CAN node n
MCU
CAN Controller
(MSCAN)
TXCAN
RXCAN
Transceiver
CAN_H
CAN_L
CAN Bus
Figure 10-2. CAN System
10.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the MSCAN.
10.3.1
Module Memory Map
Figure 10-3 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.
Register
Name
Bit 7
0x0000
CANCTL0
R
0x0001
CANCTL1
R
W
W
RXFRM
CANE
6
RXACT
CLKSRC
5
CSWAI
LOOPB
4
SYNCH
LISTEN
3
2
1
Bit 0
TIME
WUPE
SLPRQ
INITRQ
BORM
WUPM
SLPAK
INITAK
= Unimplemented or Reserved
u = Unaffected
Figure 10-3. MSCAN Register Summary
MC9S12XDP512 Data Sheet, Rev. 2.21
422
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Register
Name
0x0002
CANBTR0
R
0x0003
CANBTR1
R
0x0004
CANRFLG
R
0x0005
CANRIER
0x0006
CANTFLG
0x000D
CANMISC
3
2
1
Bit 0
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
RXERR0
TXERR7
TXERR6
TXERR5
TXERR4
TXERR3
TXERR2
TXERR1
TXERR0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
R
W
R
W
R
0x000C
Reserved
4
W
0x0008
CANTARQ
0x000B
CANIDAC
5
W
R
0x000A
CANTBSEL
6
W
0x0007
CANTIER
0x0009
CANTAAK
Bit 7
W
W
R
W
R
W
R
W
R
W
R
W
0x000E
CANRXERR
R
0x000F
CANTXERR
R
0x0010–0x0013
CANIDAR0–3
R
BOHOLD
W
W
W
= Unimplemented or Reserved
u = Unaffected
Figure 10-3. MSCAN Register Summary (continued)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
423
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Register
Name
0x0014–0x0017
CANIDMRx
R
0x0018–0x001B
CANIDAR4–7
R
0x001C–0x001F
CANIDMR4–7
R
0x0020–0x002F
CANRXFG
R
0x0030–0x003F
CANTXFG
R
W
W
W
Bit 7
6
5
4
3
2
1
Bit 0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
See Section 10.3.3, “Programmer’s Model of Message Storage”
W
See Section 10.3.3, “Programmer’s Model of Message Storage”
W
= Unimplemented or Reserved
u = Unaffected
Figure 10-3. MSCAN Register Summary (continued)
10.3.2
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.
10.3.2.1
MSCAN Control Register 0 (CANCTL0)
The CANCTL0 register provides various control bits of the MSCAN module as described below.
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 10-4. MSCAN Control Register 0 (CANCTL0)
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).
Read: Anytime
MC9S12XDP512 Data Sheet, Rev. 2.21
424
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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).
Table 10-1. CANCTL0 Register Field Descriptions
Field
Description
7
RXFRM1
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
CSWAI3
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 10.3.3, “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
WUPE4
Wake-Up Enable — This configuration bit allows the MSCAN to restart from sleep mode when traffic on CAN is
detected (see Section 10.4.5.4, “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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
425
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-1. CANCTL0 Register Field Descriptions (continued)
Field
Description
1
SLPRQ5
Sleep Mode Request — This bit requests the MSCAN to enter sleep mode, which is an internal power saving
mode (see Section 10.4.5.4, “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 10.3.2.2, “MSCAN Control Register 1 (CANCTL1)”). SLPRQ
cannot be set while the WUPIF flag is set (see Section 10.3.2.5, “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
INITRQ6,7
Initialization Mode Request — When this bit is set by the CPU, the MSCAN skips to initialization mode (see
Section 10.4.5.5, “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 10.3.2.2, “MSCAN Control Register 1 (CANCTL1)”).
The following registers enter their hard reset state and restore their default values: CANCTL08, CANRFLG9,
CANRIER10, 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.
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, the TXCAN pin is immediately forced to a recessive state when
the CPU enters wait (CSWAI = 1) or stop mode (see Section 10.4.5.2, “Operation in Wait Mode” and Section 10.4.5.3,
“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 10.3.2.6,
“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, the TXCAN pin 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.
2
10.3.2.2
MSCAN Control Register 1 (CANCTL1)
The CANCTL1 register provides various control bits and handshake status information of the MSCAN
module as described below.
MC9S12XDP512 Data Sheet, Rev. 2.21
426
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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 10-5. MSCAN Control Register 1 (CANCTL1)
Read: Anytime
Write: Anytime when INITRQ = 1 and INITAK = 1, except CANE which is write once in normal and
anytime in special system operation modes when the MSCAN is in initialization mode (INITRQ = 1 and
INITAK = 1).
Table 10-2. 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 10.4.3.2, “Clock System,” and Section Figure 10-43., “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 pin 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 10.4.4.4, “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 bits configures the bus-off state recovery mode of the MSCAN. Refer to
Section 10.5.2, “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 10.4.5.4, “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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
427
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-2. 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 10.4.5.4, “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 10.4.5.5, “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
10.3.2.3
MSCAN Bus Timing Register 0 (CANBTR0)
The CANBTR0 register configures various CAN bus timing parameters of the MSCAN module.
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 10-6. MSCAN Bus Timing Register 0 (CANBTR0)
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
Table 10-3. 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 10-4).
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 10-5).
Table 10-4. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
428
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-5. Baud Rate Prescaler
10.3.2.4
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.
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 10-7. MSCAN Bus Timing Register 1 (CANBTR1)
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
Table 10-6. 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 bit1.
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 10-44). Time segment 2 (TSEG2) values are programmable as shown in
Table 10-7.
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 10-44). Time segment 1 (TSEG1) values are programmable as shown in
Table 10-8.
1
In this case, PHASE_SEG1 must be at least 2 time quanta (Tq).
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
429
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-7. Time Segment 2 Values
1
TSEG22
TSEG21
TSEG20
Time Segment 2
0
0
0
1 Tq clock cycle1
0
0
1
2 Tq clock cycles
:
:
:
:
1
1
0
7 Tq clock cycles
1
1
1
8 Tq clock cycles
This setting is not valid. Please refer to Table 10-35 for valid settings.
Table 10-8. Time Segment 1 Values
1
TSEG13
TSEG12
TSEG11
TSEG10
Time segment 1
0
0
0
0
1 Tq clock cycle1
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
This setting is not valid. Please refer to Table 10-35 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 10-7 and Table 10-8).
Eqn. 10-1
( Prescaler value )
Bit Time = ------------------------------------------------------ • ( 1 + TimeSegment1 + TimeSegment2 )
f CANCLK
10.3.2.5
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.
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 10-8. MSCAN Receiver Flag Register (CANRFLG)
MC9S12XDP512 Data Sheet, Rev. 2.21
430
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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).
Read: Anytime
Write: Anytime when out of 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.
Table 10-9. 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 10.4.5.4,
“MSCAN Sleep Mode,”) and WUPE = 1 in CANTCTL0 (see Section 10.3.2.1, “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
4-bit (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 10.3.2.6, “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-off1: 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
431
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-9. 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
RXF2
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.
10.3.2.6
MSCAN Receiver Interrupt Enable Register (CANRIER)
This register contains the interrupt enable bits for the interrupt flags described in the CANRFLG register.
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 10-9. MSCAN Receiver Interrupt Enable Register (CANRIER)
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.
Read: Anytime
Write: Anytime when not in initialization mode
MC9S12XDP512 Data Sheet, Rev. 2.21
432
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-10. CANRIER Register Field Descriptions
Field
7
WUPIE1
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 10.3.2.1, “MSCAN Control Register 0 (CANCTL0)”) must both be enabled if the recovery
mechanism from stop or wait is required.
2
Bus-off state is defined by the CAN standard (see Bosch CAN 2.0A/B protocol specification: for only transmitters. 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 10.3.2.5, “MSCAN Receiver
Flag Register (CANRFLG)”).
10.3.2.7
MSCAN Transmitter Flag Register (CANTFLG)
The transmit buffer empty flags each have an associated interrupt enable bit in the CANTIER register.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
433
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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 10-10. MSCAN Transmitter Flag Register (CANTFLG)
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).
Read: Anytime
Write: Anytime for TXEx flags when not in initialization mode; write of 1 clears flag, write of 0 is ignored
Table 10-11. 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 10.3.2.9, “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 10.3.2.10, “MSCAN Transmitter
Message Abort Acknowledge Register (CANTAAK)”). When a TXEx flag is set, the corresponding ABTRQx bit
is cleared (see Section 10.3.2.9, “MSCAN Transmitter Message Abort Request Register (CANTARQ)”).
When listen-mode is active (see Section 10.3.2.2, “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)
10.3.2.8
MSCAN Transmitter Interrupt Enable Register (CANTIER)
This register contains the interrupt enable bits for the transmit buffer empty interrupt flags.
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 10-11. MSCAN Transmitter Interrupt Enable Register (CANTIER)
MC9S12XDP512 Data Sheet, Rev. 2.21
434
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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).
Read: Anytime
Write: Anytime when not in initialization mode
Table 10-12. CANTIER Register Field Descriptions
Field
Description
2:0
TXEIE[2:0]
10.3.2.9
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.
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 10-12. MSCAN Transmitter Message Abort Request Register (CANTARQ)
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).
Read: Anytime
Write: Anytime when not in initialization mode
Table 10-13. 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 10.3.2.7, “MSCAN Transmitter Flag Register (CANTFLG)”) and abort acknowledge flags (ABTAK, see
Section 10.3.2.10, “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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
435
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.3.2.10 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.
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 10-13. MSCAN Transmitter Message Abort Acknowledge Register (CANTAAK)
NOTE
The CANTAAK register is held in the reset state when the initialization
mode is active (INITRQ = 1 and INITAK = 1).
Read: Anytime
Write: Unimplemented for ABTAKx flags
Table 10-14. 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.
10.3.2.11 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.
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 10-14. MSCAN Transmit Buffer Selection Register (CANTBSEL)
MC9S12XDP512 Data Sheet, Rev. 2.21
436
Freescale Semiconductor
Chapter 10 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).
Read: Find the lowest ordered bit set to 1, all other bits will be read as 0
Write: Anytime when not in initialization mode
Table 10-15. 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 10.3.2.7, “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 the selection of the next
available Tx buffer.
• LDD CANTFLG; value read is 0b0000_0110
• STD CANTBSEL; value written is 0b0000_0110
• LDD CANTBSEL; value read is 0b0000_0010
If all transmit message buffers are deselected, no accesses are allowed to the CANTXFG registers.
10.3.2.12 MSCAN Identifier Acceptance Control Register (CANIDAC)
The CANIDAC register is used for identifier acceptance control as described below.
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 10-15. MSCAN Identifier Acceptance Control Register (CANIDAC)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
437
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1), except bits IDHITx, which are
read-only
Table 10-16. 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 10.4.3, “Identifier Acceptance Filter”). Table 10-17 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 10.4.3, “Identifier Acceptance Filter”). Table 10-18 summarizes the different settings.
Table 10-17. 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 10-18. 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.
10.3.2.13 MSCAN Reserved Register
This register is reserved for factory testing of the MSCAN module and is not available in normal system
operation modes.
MC9S12XDP512 Data Sheet, Rev. 2.21
438
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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
0
W
Reset:
= Unimplemented
Figure 10-16. MSCAN Reserved Register
Read: Always read 0x0000 in normal system operation modes
Write: Unimplemented in normal system operation modes
NOTE
Writing to this register when in special modes can alter the MSCAN
functionality.
10.3.2.14 MSCAN Miscellaneous Register (CANMISC)
This register provides additional features.
R
7
6
5
4
3
2
1
0
0
0
0
0
0
0
BOHOLD
W
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 10-17. MSCAN Miscellaneous Register (CANMISC)
Read: Anytime
Write: Anytime; write of ‘1’ clears flag; write of ‘0’ ignored
Table 10-19. CANMISC Register Field Descriptions
Field
0
BOHOLD
Description
Bus-off State Hold Until User Request — If BORM is set in Section 10.3.2.2, “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 10.5.2, “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
10.3.2.15 MSCAN Receive Error Counter (CANRXERR)
This register reflects the status of the MSCAN receive error counter.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
439
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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 10-18. MSCAN Receive Error Counter (CANRXERR)
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.
10.3.2.16 MSCAN Transmit Error Counter (CANTXERR)
This register reflects the status of the MSCAN transmit error counter.
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 10-19. MSCAN Transmit Error Counter (CANTXERR)
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
440
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.3.2.17 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 10.3.3.1,
“Identifier Registers (IDR0–IDR3)”) of incoming messages in a bit by bit manner (see Section 10.4.3,
“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.
Module Base + 0x0010 (CANIDAR0)
0x0011 (CANIDAR1)
0x0012 (CANIDAR2)
0x0013 (CANIDAR3)
7
6
5
4
3
2
1
0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
0
0
0
0
0
0
0
0
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
R
W
Reset
R
W
Reset
R
W
Reset
Figure 10-20. MSCAN Identifier Acceptance Registers (First Bank) — CANIDAR0–CANIDAR3
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
441
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-20. 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.
Module Base + 0x0018 (CANIDAR4)
0x0019 (CANIDAR5)
0x001A (CANIDAR6)
0x001B (CANIDAR7)
7
6
5
4
3
2
1
0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
0
0
0
0
0
0
0
0
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
R
W
Reset
R
W
Reset
R
W
Reset
Figure 10-21. MSCAN Identifier Acceptance Registers (Second Bank) — CANIDAR4–CANIDAR7
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
MC9S12XDP512 Data Sheet, Rev. 2.21
442
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-21. 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.
10.3.2.18 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.”
Module Base + 0x0014 (CANIDMR0)
0x0015 (CANIDMR1)
0x0016 (CANIDMR2)
0x0017 (CANIDMR3)
7
6
5
4
3
2
1
0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
0
0
0
0
0
0
0
0
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
R
W
Reset
R
W
Reset
R
W
Reset
Figure 10-22. MSCAN Identifier Mask Registers (First Bank) — CANIDMR0–CANIDMR3
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
443
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
Table 10-22. 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
Module Base + 0x001C (CANIDMR4)
0x001D (CANIDMR5)
0x001E (CANIDMR6)
0x001F (CANIDMR7)
7
6
5
4
3
2
1
0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
AM7
AM6
AM5
AM4
AM3
AM2
AM1
AM0
0
0
0
0
0
0
0
0
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
R
W
Reset
R
W
Reset
R
W
Reset
Figure 10-23. MSCAN Identifier Mask Registers (Second Bank) — CANIDMR4–CANIDMR7
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
MC9S12XDP512 Data Sheet, Rev. 2.21
444
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-23. 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
10.3.3
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 10.3.2.1, “MSCAN Control Register 0
(CANCTL0)”).
The time stamp register is written by the MSCAN. The CPU can only read these registers.
Table 10-24. Message Buffer Organization
Offset
Address
Register
0x00X0
Identifier Register 0
0x00X1
Identifier Register 1
0x00X2
Identifier Register 2
0x00X3
Identifier Register 3
0x00X4
Data Segment Register 0
0x00X5
Data Segment Register 1
0x00X6
Data Segment Register 2
0x00X7
Data Segment Register 3
0x00X8
Data Segment Register 4
0x00X9
Data Segment Register 5
0x00XA
Data Segment Register 6
0x00XB
Data Segment Register 7
0x00XC
Data Length Register
0x00XD
Transmit Buffer Priority Register1
0x00XE
Time Stamp Register (High Byte)2
0x00XF
Time Stamp Register (Low Byte)3
Access
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
445
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
1
Not applicable for receive buffers
Read-only for CPU
3 Read-only for CPU
2
Figure 10-24 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 10-25.
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 priority registers are 0 out of reset.
MC9S12XDP512 Data Sheet, Rev. 2.21
446
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
447
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Figure 10-24. Receive/Transmit Message Buffer — Extended Identifier Mapping
Register
Name
Bit 7
6
5
4
3
2
1
Bit0
ID28
ID27
ID26
ID25
ID24
ID23
ID22
ID21
R
IDR0
W
MC9S12XDP512 Data Sheet, Rev. 2.21
448
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Figure 10-24. Receive/Transmit Message Buffer — Extended Identifier Mapping
Register
Name
Bit 7
6
5
4
3
2
1
Bit0
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
IDR1
W
R
IDR2
W
R
IDR3
W
R
DSR0
W
R
DSR1
W
R
DSR2
W
R
DSR3
W
R
DSR4
W
R
DSR5
W
R
DSR6
W
R
DSR7
W
R
DLR
W
= Unused, always read ‘x’
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
449
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Read: For transmit buffers, anytime when TXEx flag is set (see Section 10.3.2.7, “MSCAN Transmitter
Flag Register (CANTFLG)”) and the corresponding transmit buffer is selected in CANTBSEL (see
Section 10.3.2.11, “MSCAN Transmit Buffer Selection Register (CANTBSEL)”). For receive buffers,
only when RXF flag is set (see Section 10.3.2.5, “MSCAN Receiver Flag Register (CANRFLG)”).
Write: For transmit buffers, anytime when TXEx flag is set (see Section 10.3.2.7, “MSCAN Transmitter
Flag Register (CANTFLG)”) and the corresponding transmit buffer is selected in CANTBSEL (see
Section 10.3.2.11, “MSCAN Transmit Buffer Selection Register (CANTBSEL)”). Unimplemented for
receive buffers.
Reset: Undefined (0x00XX) because of RAM-based implementation
Figure 10-25. Receive/Transmit Message Buffer — Standard Identifier Mapping
Register
Name
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
IDR0
W
R
IDR1
W
R
IDR2
W
R
IDR3
W
= Unused, always read ‘x’
10.3.3.1
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 bits. The identifier registers for a standard format identifier consist of a total of 13 bits; ID[10:0],
RTR, and IDE bits.
10.3.3.1.1
IDR0–IDR3 for Extended Identifier Mapping
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 10-26. Identifier Register 0 (IDR0) — Extended Identifier Mapping
MC9S12XDP512 Data Sheet, Rev. 2.21
450
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-25. 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.
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 10-27. Identifier Register 1 (IDR1) — Extended Identifier Mapping
Table 10-26. 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.
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 10-28. Identifier Register 2 (IDR2) — Extended Identifier Mapping
Table 10-27. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
451
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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 10-29. Identifier Register 3 (IDR3) — Extended Identifier Mapping
Table 10-28. 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
10.3.3.1.2
IDR0–IDR3 for Standard Identifier Mapping
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 10-30. Identifier Register 0 — Standard Mapping
Table 10-29. 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 10-30.
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 10-31. Identifier Register 1 — Standard Mapping
MC9S12XDP512 Data Sheet, Rev. 2.21
452
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-30. 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 10-29.
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)
7
6
5
4
3
2
1
0
x
x
x
x
x
x
x
x
R
W
Reset:
= Unused; always read ‘x’
Figure 10-32. Identifier Register 2 — Standard Mapping
7
6
5
4
3
2
1
0
x
x
x
x
x
x
x
x
R
W
Reset:
= Unused; always read ‘x’
Figure 10-33. Identifier Register 3 — Standard Mapping
10.3.3.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
453
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Module Base + 0x0004 (DSR0)
0x0005 (DSR1)
0x0006 (DSR2)
0x0007 (DSR3)
0x0008 (DSR4)
0x0009 (DSR5)
0x000A (DSR6)
0x000B (DSR7)
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 10-34. Data Segment Registers (DSR0–DSR7) — Extended Identifier Mapping
Table 10-31. DSR0–DSR7 Register Field Descriptions
Field
Description
7:0
DB[7:0]
Data bits 7:0
10.3.3.3
Data Length Register (DLR)
This register keeps the data length field of the CAN frame.
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 10-35. Data Length Register (DLR) — Extended Identifier Mapping
Table 10-32. 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 10-33 shows the effect of setting the DLC bits.
MC9S12XDP512 Data Sheet, Rev. 2.21
454
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-33. Data Length Codes
Data Length Code
10.3.3.4
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.
• 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.
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 10-36. Transmit Buffer Priority Register (TBPR)
Read: Anytime when TXEx flag is set (see Section 10.3.2.7, “MSCAN Transmitter Flag Register
(CANTFLG)”) and the corresponding transmit buffer is selected in CANTBSEL (see Section 10.3.2.11,
“MSCAN Transmit Buffer Selection Register (CANTBSEL)”).
Write: Anytime when TXEx flag is set (see Section 10.3.2.7, “MSCAN Transmitter Flag Register
(CANTFLG)”) and the corresponding transmit buffer is selected in CANTBSEL (see Section 10.3.2.11,
“MSCAN Transmit Buffer Selection Register (CANTBSEL)”).
10.3.3.5
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 10.3.2.1,
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
455
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
“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.
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 10-37. Time Stamp Register — High Byte (TSRH)
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 10-38. Time Stamp Register — Low Byte (TSRL)
Read: Anytime when TXEx flag is set (see Section 10.3.2.7, “MSCAN Transmitter Flag Register
(CANTFLG)”) and the corresponding transmit buffer is selected in CANTBSEL (see Section 10.3.2.11,
“MSCAN Transmit Buffer Selection Register (CANTBSEL)”).
Write: Unimplemented
10.4
10.4.1
Functional Description
General
This section provides a complete functional description of the MSCAN. It describes each of the features
and modes listed in the introduction.
MC9S12XDP512 Data Sheet, Rev. 2.21
456
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.4.2
Message Storage
CAN
Receive / Transmit
Engine
CPU12
Memory Mapped
I/O
Rx0
RXF
Receiver
TxBG
Tx0
MSCAN
TxFG
Tx1
TxBG
Tx2
Transmitter
CPU bus
RxFG
RxBG
MSCAN
Rx1
Rx2
Rx3
Rx4
TXE0
PRIO
TXE1
CPU bus
PRIO
TXE2
PRIO
Figure 10-39. User Model for Message Buffer Organization
MSCAN facilitates a sophisticated message storage system which addresses the requirements of a broad
range of network applications.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
457
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.4.2.1
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 10.4.2.2, “Transmit Structures.”
10.4.2.2
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 10-39.
All three buffers have a 13-byte data structure similar to the outline of the receive buffers (see
Section 10.3.3, “Programmer’s Model of Message Storage”). An additional Section 10.3.3.4, “Transmit
Buffer Priority Register (TBPR) contains an 8-bit local priority field (PRIO) (see Section 10.3.3.4,
“Transmit Buffer Priority Register (TBPR)”). The remaining two bytes are used for time stamping of a
message, if required (see Section 10.3.3.5, “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 10.3.2.7, “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 10.3.2.11, “MSCAN Transmit Buffer Selection Register
(CANTBSEL)”). This makes the respective buffer accessible within the CANTXFG address space (see
Section 10.3.3, “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
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
458
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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 10.4.7.2, “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 10.3.2.9, “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).
10.4.2.3
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 10-39). The background receive buffer (RxBG) is
exclusively associated with the MSCAN, but the foreground receive buffer (RxFG) is addressable by the
CPU (see Figure 10-39). 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 10.3.3, “Programmer’s Model of
Message Storage”).
The receiver full flag (RXF) (see Section 10.3.2.5, “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 10.4.3, “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 FIFO2, sets the RXF flag, and
generates a receive interrupt (see Section 10.4.7.3, “Receive Interrupt”) to the CPU3. 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
1. The transmit interrupt occurs only if not masked. A polling scheme can be applied on TXEx also.
2. Only if the RXF flag is not set.
3. The receive interrupt occurs only if not masked. A polling scheme can be applied on RXF also.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
459
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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 10.3.2.2, “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 10.4.7.5, “Error Interrupt”). The MSCAN remains able to transmit
messages while the receiver FIFO 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.
10.4.3
Identifier Acceptance Filter
The MSCAN identifier acceptance registers (see Section 10.3.2.12, “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 10.3.2.18, “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 10.3.2.12, “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 (see Bosch CAN 2.0A/B
protocol specification):
• 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 messages1.
This mode implements two filters for a full length CAN 2.0B compliant extended identifier.
Figure 10-40 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.
1.Although this mode can be used for standard identifiers, it is recommended to use the four or eight identifier acceptance
filters for standard identifiers
MC9S12XDP512 Data Sheet, Rev. 2.21
460
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
•
•
•
Four identifier acceptance filters, each to be applied to
— a) the 14 most significant bits of the extended identifier plus the SRR and IDE bits of CAN 2.0B
messages or
— b) the 11 bits of the standard identifier, the RTR and IDE bits of CAN 2.0A/B messages.
Figure 10-41 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 10-42 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 10-40. 32-bit Maskable Identifier Acceptance Filter
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
461
Chapter 10 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 10-41. 16-bit Maskable Identifier Acceptance Filters
MC9S12XDP512 Data Sheet, Rev. 2.21
462
Freescale Semiconductor
Chapter 10 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 10-42. 8-bit Maskable Identifier Acceptance Filters
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
463
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.4.3.1
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 10.3.2.1, “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 pin is immediately forced to a recessive state when the MSCAN goes into the power
down mode or initialization mode (see Section 10.4.5.6, “MSCAN Power Down Mode,” and
Section 10.4.5.5, “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.
10.4.3.2
Clock System
Figure 10-43 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 10-43. MSCAN Clocking Scheme
The clock source bit (CLKSRC) in the CANCTL1 register (10.3.2.2/10-426) 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
464
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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.
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. 10-2
f CANCLK
=
----------------------------------------------------Tq ( Prescaler value )A bit time is subdivided into three segments as described in the Bosch CAN specification. (see
Figure 10-44):
• 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. 10-3
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 10-44. Segments within the Bit Time
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
465
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-34. 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 10.3.2.3, “MSCAN Bus Timing Register 0 (CANBTR0)”
and Section 10.3.2.4, “MSCAN Bus Timing Register 1 (CANBTR1)”).
Table 10-35 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 10-35. 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
10.4.4
10.4.4.1
SJW
Modes of Operation
Normal Modes
The MSCAN module behaves as described within this specification in all normal system operation modes.
10.4.4.2
Special Modes
The MSCAN module behaves as described within this specification in all special system operation modes.
MC9S12XDP512 Data Sheet, Rev. 2.21
466
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.4.4.3
Emulation Modes
In all emulation modes, the MSCAN module behaves just like normal system operation modes as
described within this specification.
10.4.4.4
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
transmision. 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.
10.4.4.5
Security Modes
The MSCAN module has no security features.
10.4.5
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 10-36 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.
For all modes, an MSCAN wake-up interrupt can occur only if the MSCAN is in sleep mode (SLPRQ = 1
and SLPAK = 1), wake-up functionality is enabled (WUPE = 1), and the wake-up interrupt is enabled
(WUPIE = 1).
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
467
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
Table 10-36. CPU vs. MSCAN Operating Modes
MSCAN Mode
Reduced Power Consumption
CPU Mode
Normal
Sleep
RUN
CSWAI = X1
SLPRQ = 0
SLPAK = 0
CSWAI = X
SLPRQ = 1
SLPAK = 1
WAIT
CSWAI = 0
SLPRQ = 0
SLPAK = 0
CSWAI = 0
SLPRQ = 1
SLPAK = 1
STOP
1
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
‘X’ means don’t care.
10.4.5.1
Operation in Run Mode
As shown in Table 10-36, only MSCAN sleep mode is available as low power option when the CPU is in
run mode.
10.4.5.2
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 its internal controllers 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). The MSCAN can also operate in any of the
low-power modes depending on the values of the SLPRQ/SLPAK and CSWAI bits as seen in Table 10-36.
10.4.5.3
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 10-36).
10.4.5.4
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:
MC9S12XDP512 Data Sheet, Rev. 2.21
468
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
•
•
•
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 10-45. 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 10-45). 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. The TXCAN pin 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.
If the WUPE bit in CANCTL0 is not asserted, the MSCAN will mask any activity it detects on CAN. The
RXCAN pin is therefore held internally in a recessive state. This locks the MSCAN in sleep mode
(Figure 10-46). 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
469
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
•
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.
CAN Activity
(CAN Activity & WUPE) | SLPRQ
Wait
for Idle
StartUp
CAN Activity
SLPRQ
CAN Activity &
SLPRQ
Sleep
Idle
(CAN Activity & WUPE) |
CAN Activity
CAN Activity &
SLPRQ
CAN Activity
Tx/Rx
Message
Active
CAN Activity
Figure 10-46. Simplified State Transitions for Entering/Leaving Sleep Mode
10.4.5.5
MSCAN Initialization Mode
In initialization mode, 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 the TXCAN pin into a recessive state.
MC9S12XDP512 Data Sheet, Rev. 2.21
470
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
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 10.3.2.1, “MSCAN Control Register 0 (CANCTL0),” for a
detailed description of the initialization mode.
Bus Clock Domain
CAN Clock Domain
INITRQ
SYNC
sync.
INITRQ
sync.
SYNC
INITAK
CPU
Init Request
INITAK
Flag
INITAK
INIT
Flag
Figure 10-47. 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
Section Figure 10-47., “Initialization Request/Acknowledge Cycle”).
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.
10.4.5.6
MSCAN Power Down Mode
The MSCAN is in power down mode (Table 10-36) when
• CPU is in stop mode
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
471
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
•
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 the TXCAN pin 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.
10.4.5.7
Programmable Wake-Up Function
The MSCAN can be programmed to wake up the MSCAN as soon as CAN bus activity is detected (see
control bit WUPE in Section 10.3.2.1, “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
while in sleep mode (see control bit WUPM in Section 10.3.2.2, “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.
10.4.6
Reset Initialization
The reset state of each individual bit is listed in Section 10.3.2, “Register Descriptions,” which details all
the registers and their bit-fields.
10.4.7
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.
10.4.7.1
Description of Interrupt Operation
The MSCAN supports four interrupt vectors (see Table 10-37), any of which can be individually masked
(for details see sections from Section 10.3.2.6, “MSCAN Receiver Interrupt Enable Register
(CANRIER),” to Section 10.3.2.8, “MSCAN Transmitter Interrupt Enable Register (CANTIER)”).
MC9S12XDP512 Data Sheet, Rev. 2.21
472
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
NOTE
The dedicated interrupt vector addresses are defined in the Resets and
Interrupts chapter.
Table 10-37. Interrupt Vectors
Interrupt Source
10.4.7.2
CCR Mask
Local Enable
Wake-Up Interrupt (WUPIF)
I bit
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.
10.4.7.3
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.
10.4.7.4
Wake-Up Interrupt
A wake-up interrupt is generated if activity on the CAN bus occurs during MSCAN internal sleep mode.
WUPE (see Section 10.3.2.1, “MSCAN Control Register 0 (CANCTL0)”) must be enabled.
10.4.7.5
Error Interrupt
An error interrupt is generated if an overrun of the receiver FIFO, error, warning, or bus-off condition
occurrs. Section 10.3.2.5, “MSCAN Receiver Flag Register (CANRFLG) indicates one of the following
conditions:
• Overrun — An overrun condition of the receiver FIFO as described in Section 10.4.2.3, “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/Rx-warning, 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 10.3.2.5, “MSCAN Receiver Flag Register (CANRFLG)” and Section 10.3.2.6, “MSCAN
Receiver Interrupt Enable Register (CANRIER)”).
10.4.7.6
Interrupt Acknowledge
Interrupts are directly associated with one or more status flags in either the Section 10.3.2.5, “MSCAN
Receiver Flag Register (CANRFLG)” or the Section 10.3.2.7, “MSCAN Transmitter Flag Register
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
473
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
(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.
10.4.7.7
Recovery from Stop or Wait
The MSCAN can recover from stop or wait via the wake-up interrupt. 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).
10.5
10.5.1
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 and enter normal mode
If the configuration of registers which are writable in initialization mode needs to be changed only when
the MSCAN module is in normal mode:
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 in normal mode
10.5.2
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).
MC9S12XDP512 Data Sheet, Rev. 2.21
474
Freescale Semiconductor
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
If the MSCAN is configured for user request (BORM set in Section 10.3.2.2, “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 Section 10.3.2.14, “MSCAN Miscellaneous Register (CANMISC) has been cleared
by the user
These two events may occur in any order.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
475
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XDP512 Data Sheet, Rev. 2.21
476
Freescale Semiconductor
Chapter 11
Serial Communication Interface (S12SCIV5)
11.1
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.
11.1.1
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
11.1.2
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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
477
Chapter 11 Serial Communication Interface (S12SCIV5)
•
•
•
•
•
•
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
11.1.3
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
11.1.4
Block Diagram
Figure 11-1 is a high level block diagram of the SCI module, showing the interaction of various function
blocks.
MC9S12XDP512 Data Sheet, Rev. 2.21
478
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
SCI Data Register
RXD Data In
Infrared
Decoder
Receive Shift Register
IDLE
Receive & Wakeup
Control
Bus Clock
Baud Rate
Generator
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 11-1. SCI Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
479
Chapter 11 Serial Communication Interface (S12SCIV5)
11.2
External Signal Description
The SCI module has a total of two external pins.
11.2.1
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.
11.2.2
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.
11.3
Memory Map and Register Definition
This section provides a detailed description of all the SCI registers.
11.3.1
Module Memory Map and Register Definition
The memory map for the SCI module is given below in Figure 11-2. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
480
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2
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
SCIBDH1
R
W
SCIBDL1
R
W
SCICR11
R
W
SCIASR12
R
W
SCIACR12
R
W
SCIACR22
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
SCICR2
R
W
SCISR1
R
0
W
SCISR2
R
W
SCIDRH
R
AMAP
R8
W
SCIDRL
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 11-2. SCI Register Summary
1
2
Those registers are accessible if the AMAP bit in the SCISR2 register is set to zero
Those registers are accessible if the AMAP bit in the SCISR2 register is set to one
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
481
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2.1
R
W
Reset
SCI Baud Rate Registers (SCIBDH, SCIBDL)
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 11-3. SCI Baud Rate Register (SCIBDH)
R
W
Reset
7
6
5
4
3
2
1
0
SBR7
SBR6
SBR5
SBR4
SBR3
SBR2
SBR1
SBR0
0
0
0
0
0
0
0
0
Figure 11-4. 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 11-1. 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 11-2.
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
482
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
Table 11-2. IRSCI Transmit Pulse Width
11.3.2.2
R
W
Reset
TNP[1:0]
Narrow Pulse Width
11
1/4
10
1/32
01
1/16
00
3/16
SCI Control Register 1 (SCICR1)
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 11-5. 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 11-3. 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 11-4.
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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
483
Chapter 11 Serial Communication Interface (S12SCIV5)
Table 11-3. 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 11-4. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
484
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2.3
SCI Alternative Status Register 1 (SCIASR1)
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 11-6. SCI Alternative Status Register 1 (SCIASR1)
Read: Anytime, if AMAP = 1
Write: Anytime, if AMAP = 1
Table 11-5. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
485
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2.4
SCI Alternative Control Register 1 (SCIACR1)
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 11-7. SCI Alternative Control Register 1 (SCIACR1)
Read: Anytime, if AMAP = 1
Write: Anytime, if AMAP = 1
Table 11-6. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
486
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2.5
R
SCI Alternative Control Register 2 (SCIACR2)
7
6
5
4
3
0
0
0
0
0
0
0
0
0
0
W
Reset
2
1
0
BERRM1
BERRM0
BKDFE
0
0
0
= Unimplemented or Reserved
Figure 11-8. SCI Alternative Control Register 2 (SCIACR2)
Read: Anytime, if AMAP = 1
Write: Anytime, if AMAP = 1
Table 11-7. SCIACR2 Field Descriptions
Field
Description
2:1
Bit Error Mode — Those two bits determines the functionality of the bit error detect feature. See Table 11-8.
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 11-8. 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 11-19)
1
0
Receive input sampling occurs during the 13th time tick of a transmitted bit
(refer to Figure 11-19)
1
1
Reserved
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
487
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2.6
R
W
Reset
SCI Control Register 2 (SCICR2)
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 11-9. SCI Control Register 2 (SCICR2)
Read: Anytime
Write: Anytime
Table 11-9. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
488
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2.7
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.
R
7
6
5
4
3
2
1
0
TDRE
TC
RDRF
IDLE
OR
NF
FE
PF
1
1
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 11-10. SCI Status Register 1 (SCISR1)
Read: Anytime
Write: Has no meaning or effect
Table 11-10. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
489
Chapter 11 Serial Communication Interface (S12SCIV5)
Table 11-10. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
490
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2.8
SCI Status Register 2 (SCISR2)
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 11-11. SCI Status Register 2 (SCISR2)
Read: Anytime
Write: Anytime
Table 11-11. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
491
Chapter 11 Serial Communication Interface (S12SCIV5)
11.3.2.9
SCI Data Registers (SCIDRH, SCIDRL)
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 11-12. SCI Data Registers (SCIDRH)
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 11-13. 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 11-12. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
492
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4
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 11-14 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 11-14. Detailed SCI Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
493
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4.1
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.
11.4.1.1
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.
11.4.1.2
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.
11.4.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
494
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4.3
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 11-15 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 11-15. 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 11-13. 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
7
1
0
1
1
1
1
The address bit identifies the frame as an address
character. See Section 11.4.6.6, “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 11-14. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
495
Chapter 11 Serial Communication Interface (S12SCIV5)
1
11.4.4
The address bit identifies the frame as an address
character. See Section 11.4.6.6, “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 11-15 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 11-15. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
496
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4.5
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 11-16. Transmitter Block Diagram
11.4.5.1
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).
11.4.5.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
497
Chapter 11 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
498
Freescale Semiconductor
Chapter 11 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.
11.4.5.3
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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
499
Chapter 11 Serial Communication Interface (S12SCIV5)
Figure 11-17 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 11-17. Break Detection if BRKDFE = 1 (M = 0)
11.4.5.4
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
MC9S12XDP512 Data Sheet, Rev. 2.21
500
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4.5.5
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 11-18. 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 11-19. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
501
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4.6
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
RWU
NF
WAKE
ILT
PE
PT
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 11-20. SCI Receiver Block Diagram
11.4.6.1
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).
11.4.6.2
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,
MC9S12XDP512 Data Sheet, Rev. 2.21
502
Freescale Semiconductor
Chapter 11 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.
11.4.6.3
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 11-21) 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 11-21. Receiver Data Sampling
To verify the start bit and to detect noise, data recovery logic takes samples at RT3, RT5, and RT7.
Figure 11-16 summarizes the results of the start bit verification samples.
Table 11-16. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
503
Chapter 11 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 11-17 summarizes the results of the data bit samples.
Table 11-17. 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 11-18
summarizes the results of the stop bit samples.
Table 11-18. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
504
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
In Figure 11-22 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
RT9
1
RT10
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 11-22. Start Bit Search Example 1
In Figure 11-23, 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
LSB
Actual Start Bit
1
0
RT1
RT1
RT1
RT1
RT1
1
0
0
0
0
0
RT10
1
RT9
1
RT8
1
RT7
1
RT1
RXD
Samples
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 11-23. Start Bit Search Example 2
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
505
Chapter 11 Serial Communication Interface (S12SCIV5)
In Figure 11-24, 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 11-24. Start Bit Search Example 3
Figure 11-25 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.
LSB
Perceived and Actual Start Bit
RT1
RT1
RT1
1
1
1
1
0
RT1
1
RT1
1
RT1
1
RT1
1
RT1
1
RT1
Samples
RT1
RXD
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 11-25. Start Bit Search Example 4
MC9S12XDP512 Data Sheet, Rev. 2.21
506
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
Figure 11-26 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 11-26. Start Bit Search Example 5
In Figure 11-27, 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
1
1
1
1
1
0
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
0
0
0
1
0
1
RT10
1
RT9
1
RT8
1
RT7
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 11-27. Start Bit Search Example 6
11.4.6.4
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
507
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4.6.5
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.
11.4.6.5.1
Slow Data Tolerance
Figure 11-28 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 11-28. 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 11-28, 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 11-28, 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%
MC9S12XDP512 Data Sheet, Rev. 2.21
508
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4.6.5.2
Fast Data Tolerance
Figure 11-29 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 11-29. 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 11-29, 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 11-29, 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%
11.4.6.6
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
509
Chapter 11 Serial Communication Interface (S12SCIV5)
11.4.6.6.1
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).
11.4.6.6.2
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.
11.4.7
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 11-30. Single-Wire Operation (LOOPS = 1, RSRC = 1)
MC9S12XDP512 Data Sheet, Rev. 2.21
510
Freescale Semiconductor
Chapter 11 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.
11.4.8
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 11-31. 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.
11.5
Initialization/Application Information
11.5.1
Reset Initialization
See Section 11.3.2, “Register Descriptions”.
11.5.2
11.5.2.1
Modes of Operation
Run Mode
Normal mode of operation.
To initialize a SCI transmission, see Section 11.4.5.2, “Character Transmission”.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
511
Chapter 11 Serial Communication Interface (S12SCIV5)
11.5.2.2
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.
11.5.2.3
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.
11.5.3
Interrupt Operation
This section describes the interrupt originated by the SCI block.The MCU must service the interrupt
requests. Table 11-19 lists the eight interrupt sources of the SCI.
Table 11-19. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
512
Freescale Semiconductor
Chapter 11 Serial Communication Interface (S12SCIV5)
11.5.3.1
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.
11.5.3.1.1
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).
11.5.3.1.2
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.
11.5.3.1.3
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).
11.5.3.1.4
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).
11.5.3.1.5
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).
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
513
Chapter 11 Serial Communication Interface (S12SCIV5)
11.5.3.1.6
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.
11.5.3.1.7
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.
11.5.3.1.8
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.
11.5.4
Recovery from Wait Mode
The SCI interrupt request can be used to bring the CPU out of wait mode.
11.5.5
Recovery from Stop Mode
An active edge on the receive input can be used to bring the CPU out of stop mode.
MC9S12XDP512 Data Sheet, Rev. 2.21
514
Freescale Semiconductor
Chapter 12
Serial Peripheral Interface (S12SPIV4)
12.1
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.
12.1.1
Glossary of Terms
SPI
SS
SCK
MOSI
MISO
MOMI
SISO
12.1.2
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
• 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
12.1.3
Modes of Operation
The SPI functions in three modes: run, wait, and stop.
• Run mode
This is the basic mode of operation.
• Wait mode
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
515
Chapter 12 Serial Peripheral Interface (S12SPIV4)
•
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 a byte 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 a byte continues, so that the slave stays
synchronized to the master.
This is a high level description only, detailed descriptions of operating modes are contained in
Section 12.4.7, “Low Power Mode Options”.
12.1.4
Block Diagram
Figure 12-1 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
516
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
SPI
2
SPI Control Register 1
BIDIROE
2
SPI Control Register 2
SPC0
SPI Status Register
Slave
Control
SPIF MODF SPTEF
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
3
SPR
Port
Control
Logic
SCK
SS
Prescaler Clock Select
SPPR
MOSI
Baud Rate
Shift
Clock
Sample
Clock
3
Shifter
SPI Baud Rate Register
Data In
LSBFE=1
LSBFE=0
8
SPI Data Register
8
LSBFE=1
MSB
LSBFE=0
LSBFE=0 LSB
LSBFE=1
Data Out
Figure 12-1. SPI Block Diagram
12.2
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.
12.2.1
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.
12.2.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
517
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.2.3
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.
12.2.4
SCK — Serial Clock Pin
In master mode, this is the synchronous output clock. In slave mode, this is the synchronous input clock.
12.3
Memory Map and Register Definition
This section provides a detailed description of address space and registers used by the SPI.
12.3.1
Module Memory Map
The memory map for the SPI is given in Figure 12-2. 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
0
0
MODFEN
BIDIROE
SPISWAI
SPC0
SPPR2
SPPR1
SPPR0
SPR2
SPR1
SPR0
SPICR1
R
W
SPICR2
R
W
0
SPIBR
R
W
0
SPISR
R
W
SPIF
0
SPTEF
MODF
0
0
0
0
Reserved
R
W
SPIDR
R
W
Bit 7
6
5
4
3
2
1
Bit 0
Reserved
R
W
Reserved
R
W
0
0
= Unimplemented or Reserved
Figure 12-2. SPI Register Summary
MC9S12XDP512 Data Sheet, Rev. 2.21
518
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.3.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
519
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.3.2.1
R
W
Reset
SPI Control Register 1 (SPICR1)
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 12-3. SPI Control Register 1 (SPICR1)
Read: Anytime
Write: Anytime
Table 12-1. 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,...,15) of the SCK clock.
1 Sampling of data occurs at even edges (2,4,6,...,16) of the SCK clock.
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 12-2. 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 bit 7. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
520
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
Table 12-2. SS Input / Output Selection
12.3.2.2
R
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)
7
6
5
0
0
0
0
0
0
W
Reset
4
3
MODFEN
BIDIROE
0
0
2
0
0
1
0
SPISWAI
SPC0
0
0
= Unimplemented or Reserved
Figure 12-4. SPI Control Register 2 (SPICR2)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 12-3. SPICR2 Field Descriptions
Field
Description
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 12-4. 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
SPC0
Serial Pin Control Bit 0 — This bit enables bidirectional pin configurations as shown in Table 12-4. In master
mode, a change of this bit will abort a transmission in progress and force the SPI system into idle state.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
521
Chapter 12 Serial Peripheral Interface (S12SPIV4)
Table 12-4. Bidirectional Pin Configurations
Pin Mode
SPC0
BIDIROE
MISO
MOSI
Master Mode of Operation
Normal
0
Bidirectional
1
X
Master In
Master Out
0
MISO not used by SPI
Master In
1
Master I/O
Slave Mode of Operation
12.3.2.3
Normal
0
Bidirectional
1
6
0
W
Reset
Slave Out
Slave In
0
Slave In
MOSI not used by SPI
1
Slave I/O
SPI Baud Rate Register (SPIBR)
7
R
X
0
5
4
3
SPPR2
SPPR1
SPPR0
0
0
0
0
0
2
1
0
SPR2
SPR1
SPR0
0
0
0
= Unimplemented or Reserved
Figure 12-5. SPI Baud Rate Register (SPIBR)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 12-5. 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 12-6. 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 12-6. 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. 12-1
The baud rate can be calculated with the following equation:
Baud Rate = BusClock / BaudRateDivisor
Eqn. 12-2
NOTE
For maximum allowed baud rates, please refer to the SPI Electrical
Specification in the Electricals chapter of this data sheet.
MC9S12XDP512 Data Sheet, Rev. 2.21
522
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
Table 12-6. Example SPI Baud Rate Selection (25 MHz Bus Clock)
SPPR2
SPPR1
SPPR0
SPR2
SPR1
SPR0
Baud Rate
Divisor
Baud Rate
0
0
0
0
0
0
2
12.5 MHz
0
0
0
0
0
1
4
6.25 MHz
0
0
0
0
1
0
8
3.125 MHz
0
0
0
0
1
1
16
1.5625 MHz
0
0
0
1
0
0
32
781.25 kHz
0
0
0
1
0
1
64
390.63 kHz
0
0
0
1
1
0
128
195.31 kHz
0
0
0
1
1
1
256
97.66 kHz
0
0
1
0
0
0
4
6.25 MHz
0
0
1
0
0
1
8
3.125 MHz
0
0
1
0
1
0
16
1.5625 MHz
0
0
1
0
1
1
32
781.25 kHz
0
0
1
1
0
0
64
390.63 kHz
0
0
1
1
0
1
128
195.31 kHz
0
0
1
1
1
0
256
97.66 kHz
0
0
1
1
1
1
512
48.83 kHz
0
1
0
0
0
0
6
4.16667 MHz
0
1
0
0
0
1
12
2.08333 MHz
0
1
0
0
1
0
24
1.04167 MHz
0
1
0
0
1
1
48
520.83 kHz
0
1
0
1
0
0
96
260.42 kHz
0
1
0
1
0
1
192
130.21 kHz
0
1
0
1
1
0
384
65.10 kHz
0
1
0
1
1
1
768
32.55 kHz
0
1
1
0
0
0
8
3.125 MHz
0
1
1
0
0
1
16
1.5625 MHz
0
1
1
0
1
0
32
781.25 kHz
0
1
1
0
1
1
64
390.63 kHz
0
1
1
1
0
0
128
195.31 kHz
0
1
1
1
0
1
256
97.66 kHz
0
1
1
1
1
0
512
48.83 kHz
0
1
1
1
1
1
1024
24.41 kHz
1
0
0
0
0
0
10
2.5 MHz
1
0
0
0
0
1
20
1.25 MHz
1
0
0
0
1
0
40
625 kHz
1
0
0
0
1
1
80
312.5 kHz
1
0
0
1
0
0
160
156.25 kHz
1
0
0
1
0
1
320
78.13 kHz
1
0
0
1
1
0
640
39.06 kHz
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
523
Chapter 12 Serial Peripheral Interface (S12SPIV4)
Table 12-6. Example SPI Baud Rate Selection (25 MHz Bus Clock) (continued)
SPPR2
SPPR1
SPPR0
SPR2
SPR1
SPR0
Baud Rate
Divisor
Baud Rate
1
0
0
1
1
1
1280
19.53 kHz
1
0
1
0
0
0
12
2.08333 MHz
1
0
1
0
0
1
24
1.04167 MHz
1
0
1
0
1
0
48
520.83 kHz
1
0
1
0
1
1
96
260.42 kHz
1
0
1
1
0
0
192
130.21 kHz
1
0
1
1
0
1
384
65.10 kHz
1
0
1
1
1
0
768
32.55 kHz
1
0
1
1
1
1
1536
16.28 kHz
1
1
0
0
0
0
14
1.78571 MHz
1
1
0
0
0
1
28
892.86 kHz
1
1
0
0
1
0
56
446.43 kHz
1
1
0
0
1
1
112
223.21 kHz
1
1
0
1
0
0
224
111.61 kHz
1
1
0
1
0
1
448
55.80 kHz
1
1
0
1
1
0
896
27.90 kHz
1
1
0
1
1
1
1792
13.95 kHz
1
1
1
0
0
0
16
1.5625 MHz
1
1
1
0
0
1
32
781.25 kHz
1
1
1
0
1
0
64
390.63 kHz
1
1
1
0
1
1
128
195.31 kHz
1
1
1
1
0
0
256
97.66 kHz
1
1
1
1
0
1
512
48.83 kHz
1
1
1
1
1
0
1024
24.41 kHz
1
1
1
1
1
1
2048
12.21 kHz
MC9S12XDP512 Data Sheet, Rev. 2.21
524
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.3.2.4
R
SPI Status Register (SPISR)
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 12-6. SPI Status Register (SPISR)
Read: Anytime
Write: Has no effect
Table 12-7. SPISR Field Descriptions
Field
Description
7
SPIF
SPIF Interrupt Flag — This bit is set after a received data byte has been transferred into the SPI data register.
This bit is cleared by reading the SPISR register (with SPIF set) followed by a read access to the SPI data
register.
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. To clear
this bit and place data into the transmit data register, SPISR must be read with SPTEF = 1, followed by a write
to SPIDR. Any write to the SPI data register without reading SPTEF = 1, is effectively ignored.
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 12.3.2.2, “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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
525
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.3.2.5
R
W
Reset
SPI Data Register (SPIDR)
7
6
5
4
3
2
1
0
Bit 7
6
5
4
3
2
2
Bit 0
0
0
0
0
0
0
0
0
Figure 12-7. SPI Data Register (SPIDR)
Read: Anytime; normally read only 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 a data byte to be queued and transmitted. For an SPI configured as a master, a queued data
byte 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 a byte has been received, the received byte is transferred from the receive
shift register to the SPIDR and SPIF is set.
If SPIF is set and not serviced, and a second byte has been received, the second received byte is
kept as valid byte in the receive shift register until the start of another transmission. The byte in the
SPIDR does not change.
If SPIF is set and a valid byte is in the receive shift register, and SPIF is serviced before the start of
a third transmission, the byte in the receive shift register is transferred into the SPIDR and SPIF
remains set (see Figure 12-8).
If SPIF is set and a valid byte is in the receive shift register, and SPIF is serviced after the start of
a third transmission, the byte in the receive shift register has become invalid and is not transferred
into the SPIDR (see Figure 12-9).
MC9S12XDP512 Data Sheet, Rev. 2.21
526
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
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 12-8. 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 12-9. Reception with SPIF Serviced too Late
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
527
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4
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)
The main element of the SPI system is the SPI data register. The 8-bit data register in the master and the
8-bit data register in the slave are linked by the MOSI and MISO pins to form a distributed 16-bit register.
When a data transfer operation is performed, this 16-bit register is serially shifted eight 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
8-bit data register acts as the SPI receive data register for reads and as the SPI transmit data register for
writes. A single SPI register address is used 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 12.4.3, “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.
MC9S12XDP512 Data Sheet, Rev. 2.21
528
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4.1
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, the byte immediately transfers to the shift register. The byte 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
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 12.4.3, “Transmission Formats”).
NOTE
A change of the bits CPOL, CPHA, SSOE, LSBFE, 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
529
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4.2
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.
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 eighth 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
530
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4.3
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 12-10. Master/Slave Transfer Block Diagram
12.4.3.1
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.
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.
12.4.3.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
531
Chapter 12 Serial Peripheral Interface (S12SPIV4)
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 the 16th (last) SCK edge:
• 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 12-11 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.
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 12-11. SPI Clock Format 0 (CPHA = 0)
MC9S12XDP512 Data Sheet, Rev. 2.21
532
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
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 byte 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.
12.4.3.3
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 8-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.
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 16 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 the 16th SCK edge:
• 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 12-12 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
533
Chapter 12 Serial Peripheral Interface (S12SPIV4)
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 12-12. SPI Clock Format 1 (CPHA = 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 a new data byte is available in the SPI data
register, this byte 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
534
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4.4
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 12-3.
BaudRateDivisor = (SPPR + 1) • 2(SPR + 1)
Eqn. 12-3
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 12-6 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.
12.4.5
12.4.5.1
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 12-2.
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
535
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4.5.2
Bidirectional Mode (MOMI or SISO)
The bidirectional mode is selected when the SPC0 bit is set in SPI control register 2 (see Table 12-8). 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.
Table 12-8. Normal Mode and Bidirectional Mode
When SPE = 1
Master Mode MSTR = 1
Serial Out
Normal Mode
SPC0 = 0
MOSI
Serial In
MOSI
SPI
SPI
Serial In
MISO
Serial Out
Bidirectional Mode
SPC0 = 1
Slave Mode MSTR = 0
MOMI
Serial Out
MISO
Serial In
BIDIROE
SPI
Serial In
BIDIROE
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
536
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4.6
Error Conditions
The SPI has one error condition:
• Mode fault error
12.4.6.1
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
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.
12.4.7
12.4.7.1
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
537
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4.7.2
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).
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.
12.4.7.3
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
538
Freescale Semiconductor
Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.4.7.4
Reset
The reset values of registers and signals are described in Section 12.3, “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 byte last received from the master before the reset.
• Reading from the SPIDR after reset will always read a byte of zeros.
12.4.7.5
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.
12.4.7.5.1
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 12-2). 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 12.3.2.4, “SPI Status Register (SPISR)”.
12.4.7.5.2
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 12.3.2.4, “SPI Status Register (SPISR)”.
12.4.7.5.3
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 12.3.2.4, “SPI
Status Register (SPISR)”.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
539
Chapter 12 Serial Peripheral Interface (S12SPIV4)
MC9S12XDP512 Data Sheet, Rev. 2.21
540
Freescale Semiconductor
Chapter 13
Periodic Interrupt Timer (S12PIT24B4CV1)
13.1
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 13-1 for a simplified block diagram.
13.1.1
Glossary
Acronyms and Abbreviations
PIT
ISR
CCR
SoC
micro time bases
13.1.2
Periodic Interrupt Timer
Interrupt Service Routine
Condition Code Register
System on Chip
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.
13.1.3
Modes of Operation
Refer to the SoC guide for a detailed explanation of the chip modes.
• Run mode
This is the basic mode of operation.
• Wait mode
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
541
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
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.
•
•
13.1.4
Block Diagram
Figure 13-1 shows a block diagram of the PIT.
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 13-1. PIT Block Diagram
13.2
External Signal Description
The PIT module has no external pins.
MC9S12XDP512 Data Sheet, Rev. 2.21
542
Freescale Semiconductor
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
13.3
Memory Map and Register Definition
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
PITCFLMT
R
W
PITFLT
Bit 7
6
5
PITE
PITSWAI
PITFRZ
0
0
0
R
4
3
2
1
Bit 0
0
0
0
0
0
PFLMT1
PFLMT0
0
W
PITCE
R
PITMTLD1
W
PITLD0 (High)
R
W
PITLD0 (Low)
R
W
PITCNT0 (High) R
W
PITCNT0 (Low)
R
W
PITLD1 (High)
R
W
PCE0
PMUX3
PMUX2
PMUX1
PMUX0
PINTE3
PINTE2
PINTE1
PINTE0
PTF3
PTF2
PTF1
PTF0
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
PCNT15
PCNT14
PCNT13
PCNT12
PCNT11
PCNT10
PCNT9
PCNT8
PCNT7
PCNT6
PCNT5
PCNT4
PCNT3
PCNT2
PCNT1
PCNT0
PLD15
PLD14
PLD13
PLD12
PLD11
PLD10
PLD9
PLD8
R
R
PCE1
0
R
W
PCE2
0
R
R
PCE3
0
W
PITMTLD0
0
PFLT0
0
W
PITTF
0
PFLT1
0
W
PITINTE
0
PFLT2
0
W
PITMUX
0
PFLT3
= Unimplemented or Reserved
Figure 13-2. PIT Register Summary (Sheet 1 of 2)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
543
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
Register
Name
PITLD1 (Low)
R
W
PITCNT1 (High) R
W
PITCNT1 (Low)
R
W
PITLD2 (High)
R
W
PITLD2 (Low)
R
W
PITCNT2 (High) R
W
PITCNT2 (Low)
R
W
PITLD3 (High)
R
W
PITLD3 (Low)
R
W
PITCNT3 (High) R
W
PITCNT3 (Low)
R
W
Bit 7
6
5
4
3
2
1
Bit 0
PLD7
PLD6
PLD5
PLD4
PLD3
PLD2
PLD1
PLD0
PCNT15
PCNT14
PCNT13
PCNT12
PCNT11
PCNT10
PCNT9
PCNT8
PCNT7
PCNT6
PCNT5
PCNT4
PCNT3
PCNT2
PCNT1
PCNT0
PLD15
PLD14
PLD13
PLD12
PLD11
PLD10
PLD9
PLD8
PLD7
PLD6
PLD5
PLD4
PLD3
PLD2
PLD1
PLD0
PCNT15
PCNT14
PCNT13
PCNT12
PCNT11
PCNT10
PCNT9
PCNT8
PCNT7
PCNT6
PCNT5
PCNT4
PCNT3
PCNT2
PCNT1
PCNT0
PLD15
PLD14
PLD13
PLD12
PLD11
PLD10
PLD9
PLD8
PLD7
PLD6
PLD5
PLD4
PLD3
PLD2
PLD1
PLD0
PCNT15
PCNT14
PCNT13
PCNT12
PCNT11
PCNT10
PCNT9
PCNT8
PCNT7
PCNT6
PCNT5
PCNT4
PCNT3
PCNT2
PCNT1
PCNT0
= Unimplemented or Reserved
Figure 13-2. PIT Register Summary (Sheet 2 of 2)
MC9S12XDP512 Data Sheet, Rev. 2.21
544
Freescale Semiconductor
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
13.3.0.1
PIT Control and Force Load Micro Timer Register (PITCFLMT)
7
R
W
Reset
6
5
PITE
PITSWAI
PITFRZ
0
0
0
4
3
2
1
0
0
0
0
0
0
PFLMT1
PFLMT0
0
0
0
0
0
= Unimplemented or Reserved
Figure 13-3. PIT Control and Force Load Micro Timer Register (PITCFLMT)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 13-1. 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
down-counting 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
545
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
13.3.0.2
R
PIT Force Load Timer Register (PITFLT)
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
PFLT3
PFLT2
PFLT1
PFLT0
0
0
0
0
0
0
0
0
W
Reset
= Unimplemented or Reserved
Figure 13-4. PIT Force Load Timer Register (PITFLT)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 13-2. 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.
13.3.0.3
R
PIT Channel Enable Register (PITCE)
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
= Unimplemented or Reserved
Figure 13-5. PIT Channel Enable Register (PITCE)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 13-3. 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
down-counting.
0 The corresponding PIT channel is disabled.
1 The corresponding PIT channel is enabled.
MC9S12XDP512 Data Sheet, Rev. 2.21
546
Freescale Semiconductor
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
13.3.0.4
R
PIT Multiplex Register (PITMUX)
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
= Unimplemented or Reserved
Figure 13-6. PIT Multiplex Register (PITMUX)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 13-4. 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 immediately switched to the other
micro time base.
0 The corresponding 16-bit timer counts with micro time base 0.
1 The corresponding 16-bit timer counts with micro time base 1.
13.3.0.5
R
PIT Interrupt Enable Register (PITINTE)
7
6
5
4
0
0
0
0
0
0
0
W
Reset
0
3
2
1
0
PINTE3
PINTE2
PINTE1
PINTE0
0
0
0
0
= Unimplemented or Reserved
Figure 13-7. PIT Interrupt Enable Register (PITINTE)
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
Table 13-5. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
547
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
13.3.0.6
R
PIT Time-Out Flag Register (PITTF)
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
= Unimplemented or Reserved
Figure 13-8. PIT Time-Out Flag Register (PITTF)
Read: Anytime
Write: Anytime (write to clear); writes to the reserved bits have no effect
Table 13-6. 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.
13.3.0.7
R
W
Reset
PIT Micro Timer Load Register 0 to 1 (PITMTLD0–1)
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 13-9. PIT Micro Timer Load Register 0 (PITMTLD0)
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 13-10. PIT Micro Timer Load Register 1 (PITMTLD1)
Read: Anytime
Write: Anytime
Table 13-7. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
548
Freescale Semiconductor
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
13.3.0.8
PIT Load Register 0 to 3 (PITLD0–3)
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 13-11. PIT Load Register 0 (PITLD0)
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 13-12. PIT Load Register 1 (PITLD1)
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 13-13. PIT Load Register 2 (PITLD2)
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 13-14. PIT Load Register 3 (PITLD3)
Read: Anytime
Write: Anytime
Table 13-8. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
549
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
13.3.0.9
PIT Count Register 0 to 3 (PITCNT0–3)
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
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 13-15. PIT Count Register 0 (PITCNT0)
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 13-16. PIT Count Register 1 (PITCNT1)
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 13-17. PIT Count Register 2 (PITCNT2)
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 13-18. PIT Count Register 3 (PITCNT3)
Read: Anytime
Write: Has no meaning or effect
Table 13-9. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
550
Freescale Semiconductor
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
13.4
Functional Description
Figure 13-19 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
PMUX0
4
PITMUX Register
time-out 0
PFLT1
[1]
8-Bit Micro Timer 0
[0]
Timer 1
PITLD1 Register
PITCNT1 Register
PMUX
Clock
Timer 0
PITLD0 Register
PITCNT0 Register
PITMLD0 Register
Bus
PIT_24B4C
PFLT0
PITFLT Register
timeout 1
[2]
8-Bit Micro Timer 1
[1]
Timer 2
PITLD2 Register
PITCNT2 Register
PITCFLMT Register
4
Hardware
Trigger
PFLT2
PITMLD1 Register
Interrupt /
Trigger Interface
PITTF Register
4
timeout 2
PITINTE Register
Interrupt
Request
PFLT3
PFLMT
PMUX3
Timer 3
PITLD3 Register
PITCNT3 Register
Time-Out 3
Figure 13-19. PIT Detailed Block Diagram
13.4.1
Timer
As shown in Figure 13-1and Figure 13-19, 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
551
Chapter 13 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 13-20. 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 13-20.
Bus Clock
8-Bit Micro
Timer Counter
PITCNT Register
0
00
2
1
0
2
0001
1
0
2
0000
1
0001
0
2
1
1
2
0000
0
0001
2
1
0
0000
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 13-20. PIT Trigger and Flag Signal Timing
13.4.2
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
MC9S12XDP512 Data Sheet, Rev. 2.21
552
Freescale Semiconductor
Chapter 13 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.
13.4.3
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 13-20.
13.5
13.5.1
Initialization/Application Information
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.
13.5.2
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.
13.5.3
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
read-modify-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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
553
Chapter 13 Periodic Interrupt Timer (S12PIT24B4CV1)
MC9S12XDP512 Data Sheet, Rev. 2.21
554
Freescale Semiconductor
Chapter 14
Voltage Regulator (S12VREG3V3V5)
14.1
Introduction
Module VREG_3V3 is a dual output voltage regulator that provides two separate 2.5V (typical) supplies
differing in the amount of current that can be sourced. The regulator input voltage range is from 3.3V up
to 5V (typical).
14.1.1
Features
Module VREG_3V3 includes these distinctive features:
• Two parallel, linear voltage regulators
— Bandgap reference
• Low-voltage detect (LVD) with low-voltage interrupt (LVI)
• Power-on reset (POR)
• Low-voltage reset (LVR)
• Autonomous periodical interrupt (API)
14.1.2
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 voltage of 2.5 V with full current sourcing
capability at both outputs. Features LVD (low-voltage detect), LVR (low-voltage reset), and POR
(power-on reset) 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 and LVR are disabled. The API
is available.
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
high-impedance state, only the POR feature is available, LVD and LVR 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
555
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.1.3
Block Diagram
Figure 14-1 shows the function principle of VREG_3V3 by means of a block diagram. The regulator core
REG consists of two parallel subblocks, REG1 and REG2, providing two independent output voltages.
VDDPLL
REG2
VDDR
REG
VSSPLL
VDDA
VBG
VDD
REG1
LVD
LVR
LVR
POR
POR
VSS
VSSA
VREGEN
CTRL
LVI
API
Rate
Select
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
PIN
Figure 14-1. VREG_3V3 Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
556
Freescale Semiconductor
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.2
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 14-1 shows all signals of VREG_3V3 associated with pins.
Table 14-1. Signal Properties
Name
Function
Reset State
Pull Up
—
—
VDDR
Power input (positive supply)
VDDA
Quiet input (positive supply)
—
—
VSSA
Quiet input (ground)
—
—
VDD
Primary output (positive supply)
—
—
VSS
Primary output (ground)
—
—
VDDPLL
Secondary output (positive supply)
—
—
VSSPLL
Secondary output (ground)
—
—
VREGEN (optional)
Optional Regulator Enable
—
—
NOTE
Check device level specification for connectivity of the signals.
14.2.1
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, 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.
14.2.2
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, X7R ceramic) between VDDA and VSSA can further improve the quality of this
supply.
14.2.3
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).
In Shutdown Mode an external supply driving VDD/VSS can replace the voltage regulator.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
557
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.2.4
VDDPLL, VSSPLL — Regulator Output2 (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
(220 nF, X7R ceramic).
In Shutdown Mode, an external supply driving VDDPLL/VSSPLL can replace the voltage regulator.
14.2.5
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.
14.3
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.
14.3.1
Module Memory Map
Table 14-2 provides an overview of all used registers.
Table 14-2. Memory Map
Address
Offset
Use
Access
0x0000
HT Control Register (VREGHTCL)
—
0x0001
Control Register (VREGCTRL)
R/W
0x0002
Autonomous Periodical Interrupt Control Register (VREGAPICL)
R/W
0x0003
Autonomous Periodical Interrupt Trimming Register (VREGAPITR)
R/W
0x0004
Autonomous Periodical Interrupt Period High (VREGAPIRH)
R/W
0x0005
Autonomous Periodical Interrupt Period Low (VREGAPIRL)
R/W
0x0006
Reserved 06
—
0x0007
Reserved 07
—
MC9S12XDP512 Data Sheet, Rev. 2.21
558
Freescale Semiconductor
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.3.2
Register Descriptions
This section describes all the VREG_3V3 registers and their individual bits.
14.3.2.1
HT Control Register (VREGHTCL)
The VREGHTCL is reserved for test purposes. This register should not be written.
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 14-2. HT Control Register (VREGHTCL)
14.3.2.2
Control Register (VREGCTRL)
The VREGCTRL register allows the configuration of the VREG_3V3 low-voltage detect features.
R
7
6
5
4
3
2
0
0
0
0
0
LVDS
0
0
0
0
0
0
W
Reset
1
0
LVIE
LVIF
0
0
= Unimplemented or Reserved
Figure 14-3. Control Register (VREGCTRL)
Table 14-3. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
559
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.3.2.3
Autonomous Periodical Interrupt Control Register (VREGAPICL)
The VREGAPICL register allows the configuration of the VREG_3V3 autonomous periodical interrupt
features.
7
R
W
Reset
APICLK
0
6
5
4
3
0
0
0
0
0
0
0
0
2
1
0
APIFE
APIE
APIF
0
0
0
= Unimplemented or Reserved
Figure 14-4. Autonomous Periodical Interrupt Control Register (VREGAPICL)
Table 14-4. VREGAPICL Field Descriptions
Field
Description
7
APICLK
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.
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
560
Freescale Semiconductor
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.3.2.4
Autonomous Periodical Interrupt Trimming Register (VREGAPITR)
The VREGAPITR register allows to trim the API timeout period.
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 Device User Guide for details.
= Unimplemented or Reserved
Figure 14-5. Autonomous Periodical Interrupt Trimming Register (VREGAPITR)
Table 14-5. VREGAPITR Field Descriptions
Field
7–2
APITR[5:0]
Description
Autonomous Periodical Interrupt Period Trimming Bits — See Table 14-6 for trimming effects.
Table 14-6. 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]
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
561
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.3.2.5
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.
R
7
6
5
4
0
0
0
0
0
0
0
0
W
Reset
3
2
1
0
APIR11
APIR10
APIR9
APIR8
0
0
0
0
= Unimplemented or Reserved
Figure 14-6. Autonomous Periodical Interrupt Rate High Register (VREGAPIRH)
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 14-7. Autonomous Periodical Interrupt Rate Low Register (VREGAPIRL)
Table 14-7. VREGAPIRH / VREGAPIRL Field Descriptions
Field
Description
11-0
APIR[11:0]
Autonomous Periodical Interrupt Rate Bits — These bits define the timeout period of the API. See Table 14-8
for details of the effect of the autonomous periodical interrupt rate bits. Writable only if APIFE = 0 of VREGAPICL
register.
MC9S12XDP512 Data Sheet, Rev. 2.21
562
Freescale Semiconductor
Chapter 14 Voltage Regulator (S12VREG3V3V5)
Table 14-8. Selectable Autonomous Periodical Interrupt Periods
1
APICLK
APIR[11:0]
Selected Period
0
000
0.2 ms1
0
001
0.4 ms1
0
002
0.6 ms1
0
003
0.8 ms1
0
004
1.0 ms1
0
005
1.2 ms1
0
.....
.....
0
FFD
818.8 ms1
0
FFE
819 ms1
0
FFF
819.2 ms1
1
000
2 * bus clock period
1
001
4 * bus clock period
1
002
6 * bus clock period
1
003
8 * bus clock period
1
004
10 * bus clock period
1
005
12 * bus clock period
1
.....
.....
1
FFD
8188 * bus clock period
1
FFE
8190 * bus clock period
1
FFF
8192 * bus clock period
When trimmed within specified accuracy. See electrical specifications for details.
You can calculate the selected period depending of APICLK as:
Period = 2*(APIR[11:0] + 1) * 0.1 ms or period = 2*(APIR[11:0] + 1) * bus clock period
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
563
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.3.2.6
Reserved 06
The Reserved 06 is reserved for test purposes.
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 14-8. Reserved 06
14.3.2.7
Reserved 07
The Reserved 07 is reserved for test purposes.
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 14-9. Reserved 07
14.4
Functional Description
14.4.1
General
Module VREG_3V3 is a voltage regulator, as depicted in Figure 14-1. 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).
14.4.2
Regulator Core (REG)
Respectively its regulator core has two parallel, independent regulation loops (REG1 and REG2) that differ
only in the amount of current that can be delivered.
The regulator is a linear regulator with a bandgap reference when operated in Full Performance Mode. It
acts 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.
14.4.2.1
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
564
Freescale Semiconductor
Chapter 14 Voltage Regulator (S12VREG3V3V5)
14.4.2.2
Reduced Power Mode
In Reduced Power Mode, the gate of the output transistor is connected directly to a reference voltage to
reduce power consumption.
14.4.3
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.
14.4.4
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 power-on
sequence.
14.4.5
Low-Voltage Reset (LVR)
Block LVR monitors the primary output voltage VDD. If it drops below the assertion level (VLVRA) signal,
LVR asserts; if VDD rises above the deassertion level (VLVRD) signal, LVR deasserts. The LVR function
is available only in Full Performance Mode.
14.4.6
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.
14.4.7
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[11:0] bits determine the interrupt period. APIR[11:0] can only be written when APIFE is
cleared. As soon as APIFE is set, the timer starts running for the period selected by APIR[11:0] 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[11:0] is first to clear APIFE, then write to APICLK or
APIR[11:0], and afterwards set APIFE.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
565
Chapter 14 Voltage Regulator (S12VREG3V3V5)
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 14-6 for the trimming effect of APITR.
NOTE
The first period after enabling the counter by APIFE might be reduced.
The API internal RC oscillator clock is not available if VREG_3V3 is in
Shutdown Mode.
14.4.8
Resets
This section describes how VREG_3V3 controls the reset of the MCU.The reset values of registers and
signals are provided in Section 14.3, “Memory Map and Register Definition”. Possible reset sources are
listed in Table 14-9.
Table 14-9. Reset Sources
14.4.9
14.4.9.1
Reset Source
Local Enable
Power-on reset
Always active
Low-voltage reset
Available only in Full Performance Mode
Description of Reset Operation
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.
14.4.9.2
Low-Voltage Reset (LVR)
For details on low-voltage reset, see Section 14.4.5, “Low-Voltage Reset (LVR)”.
14.4.10 Interrupts
This section describes all interrupts originated by VREG_3V3.
The interrupt vectors requested by VREG_3V3 are listed in Table 14-10. Vector addresses and interrupt
priorities are defined at MCU level.
Table 14-10. Interrupt Vectors
Interrupt Source
Local Enable
Low-voltage interrupt (LVI)
LVIE = 1; available only in Full Performance
Mode
MC9S12XDP512 Data Sheet, Rev. 2.21
566
Freescale Semiconductor
Chapter 14 Voltage Regulator (S12VREG3V3V5)
Table 14-10. Interrupt Vectors
Interrupt Source
Local Enable
Autonomous periodical interrupt (API)
APIE = 1
14.4.10.1 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.
14.4.10.2 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
567
Chapter 14 Voltage Regulator (S12VREG3V3V5)
MC9S12XDP512 Data Sheet, Rev. 2.21
568
Freescale Semiconductor
Chapter 15
Background Debug Module (S12XBDMV2)
15.1
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
• CLKSW bit set out of reset in emulation mode.
• Family ID readable from firmware ROM at global address 0x7FFF0F (value for HCS12X devices
is 0xC1)
15.1.1
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
• 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
569
Chapter 15 Background Debug Module (S12XBDMV2)
•
•
•
•
•
•
•
•
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
CLKSW bit set out of reset in emulation mode.
When secured, hardware commands are allowed to access the register space in special single chip
mode, if the Flash and EEPROM erase tests 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)
15.1.2
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 the function during background debug mode.
15.1.2.1
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
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.
15.1.2.2
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 access to Flash or EEPROM other than allowing erasure. For
more information please see Section 15.4.1, “Security”.
MC9S12XDP512 Data Sheet, Rev. 2.21
570
Freescale Semiconductor
Chapter 15 Background Debug Module (S12XBDMV2)
15.1.2.3
Low-Power Modes
The BDM can be used until all bus masters (e.g., CPU or XGATE) 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.
15.1.3
Block Diagram
A block diagram of the BDM is shown in Figure 15-1.
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 15-1. BDM Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
571
Chapter 15 Background Debug Module (S12XBDMV2)
15.2
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.
15.3
15.3.1
Memory Map and Register Definition
Module Memory Map
Table 15-1 shows the BDM memory map when BDM is active.
Table 15-1. BDM Memory Map
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
MC9S12XDP512 Data Sheet, Rev. 2.21
572
Freescale Semiconductor
Chapter 15 Background Debug Module (S12XBDMV2)
15.3.2
Register Descriptions
A summary of the registers associated with the BDM is shown in Figure 15-2. 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
0
0
0
0
0
CCR10
CCR9
CCR8
BGAE
BGP6
BGP5
BGP4
BGP3
BGP2
BGP1
BGP0
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
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
0x7FFF07
BDMCCRH R
W
0x7FFF08
BDMGPR
R
W
0x7FFF09
Reserved
R
W
0x7FFF0A
Reserved
R
W
0x7FFF0B
Reserved
R
W
= Unimplemented, Reserved
X
= Indeterminate
= Implemented (do not alter)
0
= Always read zero
Figure 15-2. BDM Register Summary
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
573
Chapter 15 Background Debug Module (S12XBDMV2)
15.3.2.1
BDM Status Register (BDMSTS)
Register Global Address 0x7FFF01
7
R
W
ENBDM
6
5
4
3
BDMACT
0
SDV
TRACE
1
0
0
0
2
1
0
UNSEC
0
0
03
0
2
CLKSW
Reset
Special Single-Chip Mode
01
Emulation Modes
1
0
0
0
0
1
0
0
All Other Modes
0
0
0
0
0
0
0
0
= Unimplemented, Reserved
0
= Implemented (do not alter)
= Always read zero
1
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 (Flash and EEPROM). 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.
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).
Figure 15-3. BDM Status Register (BDMSTS)
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 15-2. 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 and by hardware in emulation
modes. In special single chip mode with the device secured, this bit will not be set by the firmware until
after the EEPROM and Flash erase verify tests are complete. In emulation modes with the device
secured, the BDM operations are blocked.
MC9S12XDP512 Data Sheet, Rev. 2.21
574
Freescale Semiconductor
Chapter 15 Background Debug Module (S12XBDMV2)
Table 15-2. BDMSTS Field Descriptions (continued)
Field
Description
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
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 15-3 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 mode, 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 on-chip EEPROM and 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
575
Chapter 15 Background Debug Module (S12XBDMV2)
Table 15-3. BDM Clock Sources
PLLSEL
CLKSW
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
15.3.2.2
BDMCLK
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 15-4. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
576
Freescale Semiconductor
Chapter 15 Background Debug Module (S12XBDMV2)
15.3.2.3
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
0
W
Reset
2
1
0
CCR10
CCR9
CCR8
0
0
0
= Unimplemented or Reserved
Figure 15-5. 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.
15.3.2.4
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 15-6. BDM Global Page Register (BDMGPR)
Read: All modes through BDM operation when not secured
Write: All modes through BDM operation when not secured
Table 15-4. 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.
15.3.3
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
577
Chapter 15 Background Debug Module (S12XBDMV2)
15.4
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 15.4.3, “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 15.4.4, “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 15.4.3, “BDM Hardware Commands”) and in secure mode (see Section 15.4.1,
“Security”). Firmware commands can only be executed when the system is not secure and is in active
background debug mode (BDM).
15.4.1
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 EEPROM and Flash EEPROM are 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 EEPROM or Flash do 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
EEPROM and Flash.
BDM operation is not possible in any other mode than special single chip mode when the device is secured.
The device can only be unsecured via BDM serial interface in special single chip mode. For more
information regarding security, please see the S12X_9SEC Block Guide.
15.4.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
578
Freescale Semiconductor
Chapter 15 Background Debug Module (S12XBDMV2)
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.
15.4.3
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 such
as on-chip RAM, 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 15-5.
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.
1. BDM is enabled and active immediately out of special single-chip reset.
2. This method is provided by the S12X_DBG module.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
579
Chapter 15 Background Debug Module (S12XBDMV2)
Table 15-5. 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.
WRITE_WORD
C8
16-bit address Write to memory with standard BDM firmware lookup table out of map.
16-bit data in Must be aligned access.
Command
Description
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.
15.4.4
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 15.4.2, “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 15-6.
MC9S12XDP512 Data Sheet, Rev. 2.21
580
Freescale Semiconductor
Chapter 15 Background Debug Module (S12XBDMV2)
Table 15-6. 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<f-hel
vetica><st-superscri
pt>
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.
3 System stop disables the ACK function and ignored commands will not have an ACK-pulse (e.g., CPU in stop or wait mode).
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 15.4.7, “Serial Interface Hardware Handshake Protocol” last Note).
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
581
Chapter 15 Background Debug Module (S12XBDMV2)
15.4.5
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.
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.
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 15.4.11, “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 mode. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
582
Freescale Semiconductor
Chapter 15 Background Debug Module (S12XBDMV2)
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.
Figure 15-7 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 15-7. BDM Command Structure
1. Target clock cycles are cycles measured using the target MCU’s serial clock rate. See Section 15.4.6, “BDM Serial Interface”
and Section 15.3.2.1, “BDM Status Register (BDMSTS)” for information on how serial clock rate is selected.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
583
Chapter 15 Background Debug Module (S12XBDMV2)
15.4.6
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 15.3.2.1, “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.
The timing for host-to-target is shown in Figure 15-8 and that of target-to-host in Figure 15-9 and
Figure 15-10. 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 15-8 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
584
Freescale Semiconductor
Chapter 15 Background Debug Module (S12XBDMV2)
BDM Clock
(Target MCU)
Host
Transmit 1
Host
Transmit 0
Perceived
Start of Bit Time
Target Senses Bit
Earliest
Start of
Next Bit
10 Cycles
Synchronization
Uncertainty
Figure 15-8. BDM Host-to-Target Serial Bit Timing
The receive cases are more complicated. Figure 15-9 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
host-generated 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.
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 15-9. BDM Target-to-Host Serial Bit Timing (Logic 1)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
585
Chapter 15 Background Debug Module (S12XBDMV2)
Figure 15-10 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 15-10. BDM Target-to-Host Serial Bit Timing (Logic 0)
15.4.7
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 15-11). 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
MC9S12XDP512 Data Sheet, Rev. 2.21
586
Freescale Semiconductor
Chapter 15 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 15-11. 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 15-12 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 15-12. Handshake Protocol at Command Level
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
587
Chapter 15 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 15-11 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 15.4.8, “Hardware Handshake Abort Procedure”.
15.4.8
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 15.4.9, “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
MC9S12XDP512 Data Sheet, Rev. 2.21
588
Freescale Semiconductor
Chapter 15 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 15.4.9, “SYNC — Request
Timed Reference Pulse”.
Figure 15-13 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
SYNC Response
From the Target
(Out of Scale)
READ_STATUS
Host
BDM Decode
and Starts to Execute
the READ_BYTE Command
Target
New BDM Command
Host
Target
New BDM Command
Figure 15-13. ACK Abort Procedure at the Command Level
NOTE
Figure 15-13 does not represent the signals in a true timing scale
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
589
Chapter 15 Background Debug Module (S12XBDMV2)
Figure 15-14 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.
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 15-14. 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 15.4.3, “BDM Hardware Commands” and Section 15.4.4, “Standard BDM Firmware Commands”
for more information on the BDM commands.
MC9S12XDP512 Data Sheet, Rev. 2.21
590
Freescale Semiconductor
Chapter 15 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.
15.4.9
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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
591
Chapter 15 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.
15.4.10 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
MC9S12XDP512 Data Sheet, Rev. 2.21
592
Freescale Semiconductor
Chapter 15 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.
15.4.11 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
re-activated, 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
593
Chapter 15 Background Debug Module (S12XBDMV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
594
Freescale Semiconductor
Chapter 16
Interrupt (S12XINTV1)
16.1
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
• A non-maskable unimplemented opcode trap
• A non-maskable software interrupt (SWI) or background debug mode request
• A 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 cannot be nested because the XGATE module cannot be interrupted while
processing.
NOTE
The HPRIO register and functionality of the XINT module is no longer
supported, since it is superseded by the 7-level interrupt request priority
scheme.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
595
Chapter 16 Interrupt (S12XINTV1)
16.1.1
Glossary
The following terms and abbreviations are used in the document.
Table 16-1. Terminology
Term
CCR
DMA
INT
IPL
ISR
MCU
XGATE
IRQ
XIRQ
16.1.2
•
•
•
•
•
•
•
•
•
•
•
•
Condition Code Register (in the S12X CPU)
Direct Memory Access
Interrupt
Interrupt Processing Level
Interrupt Service Routine
Micro-Controller Unit
please refer to the "XGATE Block Guide"
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).
2–113 I bit maskable interrupt vector requests (at addresses vector base + 0x0012–0x00F2).
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 opcode trap (TRAP) vector (at address vector base + 0x00F8).
Three system reset vectors (at addresses 0xFFFA–0xFFFE).
Determines the highest priority DMA 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.
16.1.3
•
Meaning
Modes of Operation
Run mode
This is the basic mode of operation.
1. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
596
Freescale Semiconductor
Chapter 16 Interrupt (S12XINTV1)
•
•
•
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 16.5.3, “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 16.5.3, “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 16.3.1.1, “Interrupt Vector Base Register (IVBR)” for details.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
597
Chapter 16 Interrupt (S12XINTV1)
16.1.4
Block Diagram
Figure 16-1 shows a block diagram of the XINT module.
Peripheral
Interrupt Requests
Wake Up
CPU
Non I Bit Maskable
Channels
PRIOLVL2
PRIOLVL1
PRIOLVL0
RQST
Priority
Decoder
Interrupt
Requests
IVBR
New
IPL
To CPU
Vector
Address
IRQ Channel
Current
IPL
One Set Per Channel
(Up to 112 Channels)
INT_XGPRIO
XGATE
Requests
Priority
Decoder
Wake up
XGATE
Vector
ID
XGATE
Interrupts
To XGATE Module
RQST
DMA 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 16-1. XINT Block Diagram
MC9S12XDP512 Data Sheet, Rev. 2.21
598
Freescale Semiconductor
Chapter 16 Interrupt (S12XINTV1)
16.2
External Signal Description
The XINT module has no external signals.
16.3
Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the XINT.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
599
Chapter 16 Interrupt (S12XINTV1)
16.3.1
Register Descriptions
This section describes in address order all the XINT 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]
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 16-2. XINT Register Summary
MC9S12XDP512 Data Sheet, Rev. 2.21
600
Freescale Semiconductor
Chapter 16 Interrupt (S12XINTV1)
16.3.1.1
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 16-3. Interrupt Vector Base Register (IVBR)
Read: Anytime
Write: Anytime
Table 16-2. 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
HCS12.
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”.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
601
Chapter 16 Interrupt (S12XINTV1)
16.3.1.2
XGATE Interrupt Priority Configuration Register (INT_XGPRIO)
Address: 0x0126
R
7
6
5
4
3
0
0
0
0
0
0
0
0
0
2
0
0
XILVL[2:0]
W
Reset
1
0
0
1
= Unimplemented or Reserved
Figure 16-4. XGATE Interrupt Priority Configuration Register (INT_XGPRIO)
Read: Anytime
Write: Anytime
Table 16-3. 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 DMA interrupts
coming from the XGATE module. Out of reset the priority is set to the lowest active level (“1”).
Table 16-4. XGATE Interrupt Priority Levels
Priority
low
high
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
MC9S12XDP512 Data Sheet, Rev. 2.21
602
Freescale Semiconductor
Chapter 16 Interrupt (S12XINTV1)
16.3.1.3
Interrupt Request Configuration Address Register (INT_CFADDR)
Address: 0x0127
7
6
R
4
INT_CFADDR[7:4]
W
Reset
5
0
0
0
1
3
2
1
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 16-5. Interrupt Configuration Address Register (INT_CFADDR)
Read: Anytime
Write: Anytime
Table 16-5. 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 interrupt vector, i.e.,
writing 0xE0 to this register selects the configuration data register block for the 8 interrupt vector requests
starting with vector (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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
603
Chapter 16 Interrupt (S12XINTV1)
16.3.1.4
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.
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 16-6. 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 16-7. 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 16-8. 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 16-9. Interrupt Request Configuration Data Register 3 (INT_CFDATA3)
1
Please refer to the notes following the PRIOLVL[2:0] description below.
MC9S12XDP512 Data Sheet, Rev. 2.21
604
Freescale Semiconductor
Chapter 16 Interrupt (S12XINTV1)
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 16-10. 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 16-11. 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 16-12. 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 16-13. 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
605
Chapter 16 Interrupt (S12XINTV1)
Table 16-6. 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.
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 HCS12 interrupt controllers. Please also refer to Table 16-7 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 User Guide 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: 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 16-7. Interrupt Priority Levels
Priority
low
high
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
MC9S12XDP512 Data Sheet, Rev. 2.21
606
Freescale Semiconductor
Chapter 16 Interrupt (S12XINTV1)
16.4
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.
16.4.1
S12X Exception Requests
The CPU handles both reset requests and interrupt requests. The XINT 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.
16.4.2
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. The
exception to this rule is the spurious interrupt vector request at (vector base + 0x0010) which cannot be
disabled, is always handled by the CPU and has a fixed priority level of 7. A priority level of 0 effectively
disables the associated 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 SWI, 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
607
Chapter 16 Interrupt (S12XINTV1)
16.4.2.1
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.
16.4.3
XGATE Requests
The XINT module processes all exception requests to be serviced by the XGATE module. The overall
priority level of those exceptions is discussed in the subsections below.
16.4.3.1
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 16.3.1.4, “Interrupt Request
Configuration Data Registers (INT_CFDATA0–7)”). The priority level setting (PRIOLVL) for this channel
becomes the DMA priority which will be used to determine the highest priority DMA request to be
serviced next by the XGATE module. Additionally, DMA interrupts may be raised by the XGATE module
by setting one or more of the XGATE channel interrupt flags (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 DMA interrupt requests is taken from the XGATE interrupt priority
configuration register (please refer to Section 16.3.1.2, “XGATE Interrupt Priority Configuration Register
(INT_XGPRIO)”). If more than one DMA interrupt request channel becomes active at the same time, the
channel with the highest vector address wins the prioritization.
16.4.4
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, XGATE module). 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 interrupt processing level into account because XGATE requests cannot
be nested.
Because the vector is not supplied until the CPU requests it, it is possible that a higher priority interrupt
request could override the original exception that 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
608
Freescale Semiconductor
Chapter 16 Interrupt (S12XINTV1)
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.
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)).
16.4.5
Reset Exception Requests
The XINT supports three system reset exception request types (please refer to CRG for details):
1. Pin reset, power-on reset, low-voltage reset, or illegal address reset
2. Clock monitor reset request
3. COP watchdog reset request
16.4.6
Exception Priority
The priority (from highest to lowest) and address of all exception vectors issued by the XINT upon request
by the CPU is shown in Table 16-8.
Table 16-8. 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 opcode trap
(Vector base + 0x00F6)
Software interrupt instruction (SWI) or BDM vector request
(Vector base + 0x00F4)
XIRQ interrupt request
(Vector base + 0x00F2)
IRQ interrupt request
(Vector base + 0x00F0–0x0012) Device specific I bit maskable interrupt sources (priority determined by the associated
configuration registers, in descending order)
(Vector base + 0x0010)
1
Spurious interrupt
16 bits vector address based
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
609
Chapter 16 Interrupt (S12XINTV1)
16.5
16.5.1
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).
16.5.2
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 16-14 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
MC9S12XDP512 Data Sheet, Rev. 2.21
610
Freescale Semiconductor
Chapter 16 Interrupt (S12XINTV1)
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 16-14. Interrupt Processing Example
16.5.3
16.5.3.1
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 are not capable
of waking up the CPU.
An XIRQ request can wake up the MCU from stop or wait mode at anytime, even if the X bit in CCR is set.
16.5.3.2
XGATE Wake Up from Stop or Wait Mode
Interrupt request channels which are configured to be handled by the XGATE are capable of waking up the
XGATE. Interrupt request channels handled by the XGATE do not affect the state of the CPU.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
611
Chapter 16 Interrupt (S12XINTV1)
MC9S12XDP512 Data Sheet, Rev. 2.21
612
Freescale Semiconductor
Chapter 17
Memory Mapping Control (S12XMMCV2)
17.1
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 1-1.
The MMC module controls the multi-master priority accesses, the selection of internal resources and
external space. 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.
17.1.1
Features
The main features of this block are:
• Paging capability to support a global 8 Mbytes memory address space
• Bus arbitration between the masters CPU, BDM, and XGATE
• Simultaneous accesses to different resources1 (internal, external, and peripherals) (see Figure 1-1)
• Resolution of target bus access collision
• Access restriction control from masters to some targets (e.g., RAM write access protection for user
specified areas)
• MCU operation mode control
• MCU security control
• Separate memory map schemes for each master CPU, BDM, and XGATE
• ROM control bits to enable the on-chip FLASH or ROM selection
• Port replacement registers access control
• 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
17.1.2
Modes of Operation
This subsection lists and briefly describes all operating modes supported by the MMC.
17.1.2.1
•
Power Saving Modes
Run mode
MMC is functional during normal run mode.
1. Resources are also called targets.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
613
Chapter 17 Memory Mapping Control (S12XMMCV2)
•
Wait mode
MMC is functional during wait mode.
Stop mode
MMC is inactive during stop mode.
•
17.1.2.2
•
Functional Modes
Single chip modes
In normal and special single chip mode the internal memory is used. External bus is not active.
Expanded modes
Address, data, and control signals are activated in normal expanded and special test modes when
accessing the external bus.
Emulation modes
External bus is active to emulate via an external tool the normal expanded or the normal single chip
mode.
•
•
17.1.3
Block Diagram
Figure 1-1 shows a block diagram of the MMC.
BDM
EBI
CPU
XGATE
MMC
Address Decoder & Priority
DBG
EEPROM
Target Bus Controller
FLASH
RAM
Peripherals
Figure 17-1. MMC Block Diagram
17.2
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.
MC9S12XDP512 Data Sheet, Rev. 2.21
614
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
Table 1-2 and Table 1-3 outline the pin names and functions. It also provides a brief description of their
operation.
Table 17-1. External Input Signals Associated with the MMC
Signal
I/O
Description
Availability
MODC
I
Mode input
MODB
I
Mode input
Latched after
RESET (active low)
MODA
I
Mode input
EROMCTL
I
EROM control input
ROMCTL
I
ROM control input
Table 17-2. External Output Signals Associated with the MMC
Available in Modes
Signal
I/O
Description
NS
CS0
O
Chip select line 0
CS1
O
Chip select line 1
CS2
O
Chip select line 2
CS3
O
Chip select line 3
SS
NX
ES
EX
ST
(see Table 1-4)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
615
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3
17.3.1
Memory Map and Registers
Module Memory Map
A summary of the registers associated with the MMC block is shown in Figure 1-2. Detailed descriptions
of the registers and bits are given in the subsections that follow.
Address
Register
Name
0x000A
MMCCTL0
R
Bit 7
6
5
4
3
2
1
Bit 0
0
0
0
0
CS3E
CS2E
CS1E
CS0E
MODC
MODB
MODA
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
0
EROMON
ROMHM
ROMON
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RP7
RP6
RP5
RP4
RP3
RP2
RP1
RP0
EP7
EP6
EP5
EP4
EP3
EP2
EP1
EP0
PIX7
PIX6
PIX5
PIX4
PIX3
PIX2
PIX1
PIX0
0
0
0
0
0
0
0
0
W
0x000B
MODE
R
W
0x0010
GPAGE
R
0
W
0x0011
DIRECT
R
W
0x0012
Reserved
R
W
0x0013
MMCCTL1
R
W
0x0014
Reserved
R
W
0x0015
Reserved
R
W
0x0016
RPAGE
R
W
0x0017
EPAGE
R
W
0x0030
PPAGE
R
W
0x0031
Reserved
R
W
= Unimplemented or Reserved
Figure 17-2. MMC Register Summary
MC9S12XDP512 Data Sheet, Rev. 2.21
616
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
Address
Register
Name
0x011C
RAMWPC
Bit 7
R
RAMXGU
R
1
W
0x011E
RAMSHL
R
1
W
0x011F
RAMSHU
5
4
3
2
0
0
0
0
0
XGU6
XGU5
XGU4
XGU3
SHL6
SHL5
SHL4
SHU6
SHU5
SHU4
RPWE
W
0x011D
6
R
1
W
1
Bit 0
AVIE
AVIF
XGU2
XGU1
XGU0
SHL3
SHL2
SHL1
SHL0
SHU3
SHU2
SHU1
SHU0
= Unimplemented or Reserved
Figure 17-2. MMC Register Summary
17.3.2
17.3.2.1
Register Descriptions
MMC Control Register (MMCCTL0)
Address: 0x000A PRR
R
7
6
5
4
0
0
0
0
0
0
0
0
W
Reset
3
2
1
0
CS3E
CS2E
CS1E
CS0E
0
0
0
ROMON1
1. ROMON is bit[0] of the register MMCTL1 (see Figure 1-10)
= Unimplemented or Reserved
Figure 17-3. MMC Control Register (MMCCTL0)
Read: Anytime. In emulation modes read operations will return the data from the external bus. In all other
modes the data is read from this register.
Write: Anytime. In emulation modes write operations will also be directed to the external bus.
Table 17-3. Chip Selects Function Activity
Chip Modes
Register Bit
NS
CS3E, CS2E, CS1E, CS0E
1
2
Disabled1
SS
Disabled
NX
Enabled
2
ES
EX
ST
Disabled
Enabled
Enabled
Disabled: feature always inactive.
Enabled: activity is controlled by the appropriate register bit value.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
617
Chapter 17 Memory Mapping Control (S12XMMCV2)
The MMCCTL0 register is used to control external bus functions, i.e., availability of chip selects.
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
Table 17-4. MMCCTL0 Field Descriptions
Field
Description
3–0
CS[3:0]E
Chip Select Enables — Each of these bits enables one of the external chip selects CS3, CS2, CS1, and CS0
outputs which are asserted during accesses to specific external addresses. The associated global address
ranges are shown in Table 1-6 and Table 1-21 and Figure 1-23.
Chip selects are only active if enabled in normal expanded mode, Emulation expanded mode and special test
mode. The function disabled in all other operating modes.
0 Chip select is disabled
1 Chip select is enabled
Table 17-5. Chip Select Signals
1
Global Address Range
Asserted Signal
0x00_0800–0x0F_FFFF
CS3
0x10_0000–0x1F_FFFF
CS2
0x20_0000–0x3F_FFFF
CS1
0x40_0000–0x7F_FFFF
CS01
When the internal NVM is enabled (see ROMON in Section 1.3.2.5, “MMC Control
Register (MMCCTL1)”) the CS0 is not asserted in the space occupied by this on-chip
memory block.
MC9S12XDP512 Data Sheet, Rev. 2.21
618
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3.2.2
Mode Register (MODE)
Address: 0x000B PRR
7
R
W
Reset
6
5
MODC
MODB
MODA
MODC1
MODB1
MODA1
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
1. External signal (see Table 1-2).
= Unimplemented or Reserved
Figure 17-4. Mode Register (MODE)
Read: Anytime. In emulation modes read operations will return the data read from the external bus. In all
other modes the data are read from this register.
Write: Only if a transition is allowed (see Figure 1-5). In emulation modes write operations will be also
directed to the external bus.
The MODE bits of the MODE register are used to establish the MCU operating mode.
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
Table 17-6. MODE Field Descriptions
Field
Description
7–5
MODC,
MODB,
MODA
Mode Select Bits — These bits control the current operating mode during RESET high (inactive). The external
mode pins MODC, MODB, and MODA determine the operating mode during RESET low (active). The state of
the pins is latched into the respective register bits after the RESET signal goes inactive (see Figure 1-5).
Write restrictions exist to disallow transitions between certain modes. Figure 1-5 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.
Both transitions from normal single-chip mode to normal expanded mode and from emulation single-chip to
emulation expanded mode are only executed by writing a value of 0b101 (write once). Writing any other value
will not change the MODE bits, but will block further writes to these register bits.
Changes of operating modes are not allowed when the device is secured, but it will block further writes to these
register bits except in special modes.
In emulation modes reading this address returns data from the external bus which has to be driven by the
emulator. It is therefore responsibility of the emulator hardware to provide the expected value (i.e. a value
corresponding to normal single chip mode while the device is in emulation single-chip mode or a value
corresponding to normal expanded mode while the device is in emulation expanded mode).
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
619
Chapter 17 Memory Mapping Control (S12XMMCV2)
RESET
010
Special
Test
(ST)
010
1
1
10
0
10
Normal
Expanded
(NX)
101
Emulation
Single-Chip
(ES)
001
Emulation
Expanded
(EX)
011
101
10
1
011
RESET
0
10
RESET
RESET
000
001
101
101
010
110
111
Normal
Single-Chip
(NS)
100
1
00
01
RESET
100
1
01
1
00
Special
Single-Chip
(SS)
000
000
RESET
Transition done by external pins (MODC, MODB, MODA)
RESET
Transition done by write access to the MODE register
110
111
Illegal (MODC, MODB, MODA) pin values.
Do not use. (Reserved for future use).
Figure 17-5. Mode Transition Diagram when MCU is Unsecured
MC9S12XDP512 Data Sheet, Rev. 2.21
620
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3.2.3
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 17-6. Global Page Index Register (GPAGE)
Read: Anytime
Write: Anytime
The global page index register is used only 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 1-7).
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
Global Address [22:0]
Bit22
Bit16 Bit15
GPAGE Register [6:0]
Bit 0
CPU Address [15:0]
Figure 17-7. GPAGE Address Mapping
Table 17-7. 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 64-kilobyte pages is
to be accessed.
Example 17-1. This example demonstrates usage of the GPAGE register
LDAADR
MOVB
GLDAA
EQU $5000
#$14, GPAGE
>LDAADR
;Initialize LDADDR to the value of $5000
;Initialize GPAGE register with the value of $14
;Load Accu A from the global address $14_5000
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
621
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3.2.4
Direct Page Register (DIRECT)
Address: 0x0011
R
W
Reset
7
6
5
4
3
2
1
0
DP15
DP14
DP13
DP12
DP11
DP10
DP9
DP8
0
0
0
0
0
0
0
0
Figure 17-8. Direct Register (DIRECT)
Read: Anytime
Write: anytime in special modes, one time only in other modes.
This register determines the position of the direct page within the memory map.
Table 17-8. 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 1-9).
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
Global Address [22:0]
Bit22
Bit16 Bit15
Bit8
Bit7
Bit0
DP [15:8]
CPU Address [15:0]
Figure 17-9. 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 Expansion of the CPU Local Address Map).
Example 17-2. This example demonstrates usage of the Direct Addressing Mode by a global instruction
LDAADR
MOVB
MOVB
GLDAA
EQU $0000
#$80,DIRECT
#$14,GPAGE
<LDAADR
;Initialize LDADDR with the value of $0000
;Initialize DIRECT register with the value of $80
;Initialize GPAGE register with the value of $14
;Load Accu A from the global address $14_8000
MC9S12XDP512 Data Sheet, Rev. 2.21
622
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3.2.5
MMC Control Register (MMCCTL1)
Address: 0x0013 PRR
R
7
6
5
4
3
0
0
0
0
0
0
0
0
0
0
W
Reset
2
1
0
EROMON
ROMHM
ROMON
EROMCTL
0
ROMCTL
= Unimplemented or Reserved
Figure 17-10. MMC Control Register (MMCCTL1)
Read: Anytime. In emulation modes read operations will return the data from the external bus. In all other
modes the data are read from this register.
Write: Refer to each bit description. In emulation modes write operations will also be directed to the
external bus.
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
Table 17-9. MMCCTL1 Field Descriptions
Field
2
EROMON
Description
Enables emulated Flash or ROM memory in the memory map
Write: Never
0 Disables the emulated Flash or ROM in the memory map.
1 Enables the emulated Flash or ROM in the memory map.
1
ROMHM
FLASH or ROM only in higher Half of Memory Map
Write: Once in normal and emulation modes and anytime in special modes
0 The fixed page of Flash or ROM can be accessed in the lower half of the memory map. Accesses to
$4000–$7FFF will be mapped to $7F_4000-$7F_7FFF in the global memory space.
1 Disables access to the Flash or ROM in the lower half of the memory map.These physical locations of the
Flash or ROM can still be accessed through the program page window. Accesses to $4000–$7FFF will be
mapped to $14_4000-$14_7FFF in the global memory space (external access).
0
ROMON
Enable FLASH or ROM in the memory map
Write: Once in normal and emulation modes and anytime in special modes
0 Disables the Flash or ROM from the memory map.
1 Enables the Flash or ROM in the memory map.
EROMON and ROMON control the visibility of the Flash in the memory map for CPU or BDM (not for
XGATE). Both local and global memory maps are affected.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
623
Chapter 17 Memory Mapping Control (S12XMMCV2)
Table 17-10. Data Sources when CPU or BDM is Accessing Flash Area
Chip Modes
ROMON
EROMON
DATA SOURCE1
Stretch2
Normal Single Chip
X
X
Internal
N
X
0
Emulation Memory
N
X
1
Internal Flash
0
X
External Application
Y
1
X
Internal Flash
N
0
X
External Application
Y
1
0
Emulation Memory
N
1
1
Internal Flash
0
X
External Application
1
X
Internal Flash
Special Single Chip
Emulation Single Chip
Normal Expanded
Emulation Expanded
Special Test
N
1
Internal means resources inside the MCU are read/written.
Internal Flash means Flash resources inside the MCU are read/written.
Emulation memory means resources inside the emulator are read/written (PRU registers, flash
replacement, RAM, EEPROM and register space are always considered internal).
External application means resources residing outside the MCU are read/written.
2
The external access stretch mechanism is part of the EBI module (refer to EBI Block Guide for details).
17.3.2.6
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 17-11. RAM Page Index Register (RPAGE)
Read: Anytime
Write: Anytime
The RAM page index register allows accessing up to (1M minus 2K) bytes of RAM in the global memory
map by using the eight page index bits to page 4 Kbyte blocks into the RAM page window located in the
CPU local memory map from address $1000 to address $1FFF (see Figure 1-12).
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
MC9S12XDP512 Data Sheet, Rev. 2.21
624
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
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 17-12. 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 = $00.
Table 17-11. 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 $FD ensures that there is a linear RAM space available between addresses $1000 and
$3FFF out of reset.
The fixed 4K page from $2000–$2FFF of RAM is equivalent to page 254 (page number $FE).
The fixed 4K page from $3000–$3FFF of RAM is equivalent to page 255 (page number $FF).
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
625
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3.2.7
EEPROM 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 17-13. EEPROM Page Index Register (EPAGE)
Read: Anytime
Write: Anytime
The EEPROM page index register allows accessing up to 256 Kbyte of EEPROM in the global memory
map by using the eight page index bits to page 1 Kbyte blocks into the EEPROM page window located in
the local CPU memory map from address $0800 to address $0BFF (see Figure 1-14).
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
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 17-14. EPAGE Address Mapping
Table 17-12. EPAGE Field Descriptions
Field
7–0
EP[7:0]
Description
EEPROM Page Index Bits 7–0 — These page index bits are used to select which of the 256 EEPROM array
pages is to be accessed in the EEPROM Page Window.
The reset value of $FE ensures that there is a linear EEPROM space available between addresses $0800
and $0FFF out of reset.
The fixed 1K page $0C00–$0FFF of EEPROM is equivalent to page 255 (page number $FF).
MC9S12XDP512 Data Sheet, Rev. 2.21
626
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3.2.8
Program Page Index Register (PPAGE)
Address: 0x0030
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 17-15. Program Page Index Register (PPAGE)
Read: Anytime
Write: Anytime
The program page index register allows accessing up to 4 Mbyte of FLASH or ROM in the global memory
map by using the eight page index bits to page 16 Kbyte blocks into the program page window located in
the CPU local memory map from address $8000 to address $BFFF (see Figure 1-16). The CPU has a
special access to read and write this register during execution of CALL and RTC instructions.
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
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 17-16. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
627
Chapter 17 Memory Mapping Control (S12XMMCV2)
Table 17-13. 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 fixed 16K page from $4000–$7FFF (when ROMHM = 0) is the page number $FD.
The reset value of $FE ensures that there is linear Flash space available between addresses $4000 and
$FFFF out of reset.
The fixed 16K page from $C000-$FFFF is the page number $FF.
17.3.2.9
RAM Write Protection Control Register (RAMWPC)
Address: 0x011C
7
R
W
Reset
RWPE
0
6
5
4
3
2
0
0
0
0
0
0
0
0
0
0
1
0
AVIE
AVIF
0
0
= Unimplemented or Reserved
Figure 17-17. RAM Write Protection Control Register (RAMWPC)
Read: Anytime
Write: Anytime
Table 17-14. RAMWPC Field Descriptions
Field
Description
7
RWPE
RAM Write Protection Enable — This bit enables the RAM write protection mechanism. When the RWPE bit
is cleared, there is no write protection and any memory location is writable by the CPU module and the XGATE
module. When the RWPE bit is set the write protection mechanism is enabled and write access of the CPU or
to the XGATE RAM region. Write access performed by the XGATE module to outside of the XGATE RAM region
or the shared region is suppressed as well in this case.
0 RAM write protection check is disabled, region boundary registers can be written.
1 RAM write protection check is enabled, region boundary registers cannot be written.
1
AVIE
CPU Access Violation Interrupt Enable — This bit enables the Access Violation Interrupt. If AVIE is set and
AVIF is set, an interrupt is generated.
0 CPU Access Violation Interrupt Disabled.
1 CPU Access Violation Interrupt Enabled.
0
AVIF
CPU Access Violation Interrupt Flag — When set, this bit indicates that the CPU has tried to write a memory
location inside the XGATE RAM region. This flag can be reset by writing’1’ to the AVIF bit location.
0 No access violation by the CPU was detected.
1 Access violation by the CPU was detected.
MC9S12XDP512 Data Sheet, Rev. 2.21
628
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3.2.10 RAM XGATE Upper Boundary Register (RAMXGU)
Address: 0x011D
7
R
1
W
Reset
1
6
5
4
3
2
1
0
XGU6
XGU5
XGU4
XGU3
XGU2
XGU1
XGU0
1
1
1
1
1
1
1
= Unimplemented or Reserved
Figure 17-18. RAM XGATE Upper Boundary Register (RAMXGU)
Read: Anytime
Write: Anytime when RWPE = 0
Table 17-15. RAMXGU Field Descriptions
Field
Description
6–0
XGU[6:0]
XGATE Region Upper Boundary Bits 6-0 — These bits define the upper boundary of the RAM region allocated
to the XGATE module in multiples of 256 bytes. The 256 byte block selected by this register is included in the
region. See Figure 1-25 for details.
17.3.2.11 RAM Shared Region Lower Boundary Register (RAMSHL)
Address: 0x011E
7
R
1
W
Reset
1
6
5
4
3
2
1
0
SHL6
SHL5
SHL4
SHL3
SHL2
SHL1
SHL0
1
1
1
1
1
1
1
= Unimplemented or Reserved
Figure 17-19. RAM Shared Region Lower Boundary Register (RAMSHL)
Read: Anytime
Write: Anytime when RWPE = 0
Table 17-16. RAMSHL Field Descriptions
Field
Description
6–0
SHL[6:0]
RAM Shared Region Lower Boundary Bits 6–0 — These bits define the lower boundary of the shared memory
region in multiples of 256 bytes. The block selected by this register is included in the region. See Figure 1-25 for
details.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
629
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.3.2.12 RAM Shared Region Upper Boundary Register (RAMSHU)
Address: 0x011F
7
R
1
W
Reset
1
6
5
4
3
2
1
0
SHU6
SHU5
SHU4
SHU3
SHU2
SHU1
SHU0
1
1
1
1
1
1
1
= Unimplemented or Reserved
Figure 17-20. RAM Shared Region Upper Boundary Register (RAMSHU)
Read: Anytime
Write: Anytime when RWPE = 0
Table 17-17. RAMSHU Field Descriptions
Field
Description
6–0
SHU[6:0]
RAM Shared Region Upper Boundary Bits 6–0 — These bits define the upper boundary of the shared
memory in multiples of 256 bytes. The block selected by this register is included in the region. See Figure 1-25
for details.
17.4
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.
17.4.1
•
•
•
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.
Emulation single-chip mode
Tool vendors use this mode for emulation systems in which the user’s target application is normal
single-chip mode. Code is executed from external or internal memory depending on the set-up of
the EROMON bit (see Section 1.3.2.5, “MMC Control Register (MMCCTL1)”). The external bus
is active in both cases to allow observation of internal operations (internal visibility).
MC9S12XDP512 Data Sheet, Rev. 2.21
630
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
•
•
•
Normal expanded mode
The external bus interface is configured as an up to 23-bit address bus, 8 or 16-bit data bus with
dedicated bus control and status signals. This mode allows 8 or 16-bit external memory and
peripheral devices to be interfaced to the system. The fastest external bus rate is half of the internal
bus rate. An external signal can be used in this mode to cause the external bus to wait as desired by
the external logic.
Emulation expanded mode
Tool vendors use this mode for emulation systems in which the user’s target application is normal
expanded mode.
Special test mode
This mode is an expanded mode for factory test.
17.4.2
17.4.2.1
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 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 MCU enters active BDM mode the BDM firmware lookup tables and the BDM registers become
visible in the local memory map between addresses $FF00 and $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 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 $BF00 and $BFFF if the PPAGE register contains value of
$FF.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
631
Chapter 17 Memory Mapping Control (S12XMMCV2)
CPU or BDM
Local Memory Map
Global Memory Map
$00_0000
2K Registers
$00_0800
$00_1000
$0000
RAM
253*4K paged
2K Registers
$0800
EEPROM
1K window
EPAGE
1M minus Kbytes
2K RAM
$0F_E000
8K RAM
$0C00
1K EEPROM
$10_0000
RAM
4K window
EEPROM
255*1K paged
RPAGE
$2000
$13_FC00
256 Kbytes
$1000
1K EEPROM
8K RAM
$14_4000
$4000
ROMHM=1
$14_8000
Unpaged Flash
External
Space
No
2.75 Mbytes
$14_0000
$40_0000
$8000
Flash
16K window
PPAGE
PPAGES
253 * 16K
Unpaged Flash
$FFFF
$7F_4000
Reset Vectors
16K Unpaged
or PPAGE $FD
$7F_8000
16K Unpaged
or PPAGE $FE
$7F_C000
16K Unpaged
or PPAGE $FF
$7F_FFFF
4 Mbytes
$C000
Figure 17-21. Expansion of the Local Address Map
MC9S12XDP512 Data Sheet, Rev. 2.21
632
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.4.2.1.1
Expansion of the Local Address Map
Expansion of the CPU Local Address Map
The program page index register in MMC allows accessing up to 4 Mbyte of FLASH or ROM in the global
memory map by using the eight page index bits to page 256 16 Kbyte blocks into the program page
window located from address $8000 to address $BFFF in the local CPU memory map.
The page value for the program page window is stored in the PPAGE register. The value of the PPAGE
register can be read or written by normal memory accesses as well as by the CALL and RTC instructions
(see Section 1.5.1, “CALL and RTC Instructions”).
Control registers, vector space and parts of the on-chip memories are located in unpaged portions of the
64-kilobyte local CPU address space.
The starting address of an interrupt service routine must be located in unpaged memory unless the user is
certain that the PPAGE register will be set to the appropriate value when the service routine is called.
However an interrupt service routine can call other routines that are in paged memory. The upper
16-kilobyte block of the local CPU memory space ($C000–$FFFF) is unpaged. It is recommended that all
reset and interrupt vectors point to locations in this area or to the other upages sections of the local CPU
memory map.
Table 1-19 summarizes mapping of the address bus in Flash/External space based on the address, the
PPAGE register value and value of the ROMHM bit in the MMCCTL1 register.
Table 17-18. Global FLASH/ROM Allocated
Local
CPU Address
ROMHM
External
Access
Global Address
$4000–$7FFF
0
No
$7F_4000 –$7F_7FFF
1
Yes
$14_4000–$14_7FFF
N/A
No1
$40_0000–$7F_FFFF
N/A
Yes1
N/A
No
$8000–$BFFF
$C000–$FFFF
1
$7F_C000–$7F_FFFF
The internal or the external bus is accessed based on the size of the memory resources
implemented on-chip. Please refer to Figure 1-23 for further details.
The RAM page index register allows accessing up to 1 Mbyte –2 Kbytes of RAM in the global memory
map by using the eight RPAGE index bits to page 4 Kbyte blocks into the RAM page window located in
the local CPU memory space from address $1000 to address $1FFF. The EEPROM page index register
EPAGE allows accessing up to 256 Kbytes of EEPROM in the system by using the eight EPAGE index
bits to page 1 Kbyte blocks into the EEPROM page window located in the local CPU memory space from
address $0800 to address $0BFF.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
633
Chapter 17 Memory Mapping Control (S12XMMCV2)
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.
17.4.2.2
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 8 Mbyte 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
EEPROM as well as additional external memory.
The GPAGE Register is used only when the CPU is executing a global instruction (see Section 1.3.2.3,
“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 1-7).
BDM Global Addresses Based on the Global Page
The seven BDMGPR Global Page index bits allow access to the full 8 Mbyte 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 EEPROM as well as additional external memory.
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 1-22).
MC9S12XDP512 Data Sheet, Rev. 2.21
634
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
BDM HARDWARE COMMAND
Global Address [22:0]
Bit22
Bit16 Bit15
Bit0
BDMGPR Register [6:0]
BDM Local Address
BDM FIRMWARE COMMAND
Global Address [22:0]
Bit22
Bit16 Bit15
Bit0
BDMGPR Register [6:0]
CPU Local Address
Figure 17-22. BDMGPR Address Mapping
17.4.2.3
Implemented Memory Map
The global memory spaces reserved for the internal resources (RAM, EEPROM, 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 Device User Guide for further details.
Figure 17-23 and Table 17-20 show the memory spaces occupied by the on-chip resources. Please note that
the memory spaces have fixed top addresses.
Table 17-19. Global Implemented Memory Space
Internal Resource
Bottom Address
Top Address
Registers
$00_0000
$00_07FF
RAM
$10_0000 minus RAMSIZE1
EEPROM
FLASH
$14_0000 minus EEPROMSIZE
$80_0000 minus
$0F_FFFF
2
FLASHSIZE3
$13_FFFF
$7F_FFFF
1
RAMSIZE is the hexadecimal value of RAM SIZE in bytes
EEPROMSIZE is the hexadecimal value of EEPROM SIZE in bytes
3 FLASHSIZE is the hexadecimal value of FLASH SIZE in bytes
2
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
635
Chapter 17 Memory Mapping Control (S12XMMCV2)
When the device is operating in expanded modes except emulation single-chip mode, accesses to the
global addresses which are not occupied by the on-chip resources (unimplemented areas or external space)
result in accesses to the external bus (see Figure 17-23).
In emulation single-chip mode, accesses to the global addresses which are not occupied by the on-chip
resources (unimplemented areas) result in accesses to the external bus. CPU accesses to the global
addresses which are occupied by the external space result in an illegal access reset (system reset). The
BDM accesses to the external space are performed but the data is undefined.
In single-chip modes an access to any of the unimplemented areas (see Figure 17-23) by the CPU (except
firmware commands) results in an illegal access reset (system reset). The BDM accesses to the
unimplemented areas are performed but the data is undefined.
Misaligned word accesses to the last location (Top address) of any of the on-chip resource blocks (except
RAM) by the CPU is performed in expanded modes. In single-chip modes these accesses (except Flash)
result in an illegal access reset (except firmware commands).
Misaligned word accesses to the last location (top address) of the on-chip RAM by the CPU is ignored in
expanded modes (read of undefined data). In single-chip modes these accesses result in an illegal access
reset (except firmware commands).
No misaligned word access from the BDM module will occur. These accesses are blocked in the BDM
(Refer to BDM Block Guide).
Misaligned word accesses to the last location of any global page (64 Kbyte) by using global instructions,
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.
The non internal resources (unimplemented areas or external space) are used to generate the chip selects
(CS0,CS1,CS2 and CS3) (see Figure 17-23), which are only active in normal expanded mode, emulation
expanded mode, and special test mode (see Section 1.3.2.1, “MMC Control Register (MMCCTL0)”).
Table 1-21 shows the address boundaries of each chip select and the relationship with the implemented
resources (internal) parameters.
Table 17-20. Global Chip Selects Memory Space
Chip Selects
Bottom Address
Top Address
CS3
$00_0800
$0F_FFFF minus RAMSIZE1
CS2
$10_0000
$13_FFFF minus EEPROMSIZE2
CS23
$14_0000
$1F_FFFF
CS1
$20_0000
$3F_FFFF
CS04
$40_0000
$7F_FFFF minus FLASHSIZE5
1
External RPAGE accesses in (NX, EX and ST)
External EPAGE accesses in (NX, EX and ST)
3 When ROMHM is set (see ROMHM in Table 1-19) the CS2 is asserted in the space occupied by this on-chip
memory block.
4
When the internal NVM is enabled (see ROMON in Section 1.3.2.5, “MMC Control Register (MMCCTL1)”)
the CS0 is not asserted in the space occupied by this on-chip memory block.
5 External PPAGE accesses in (NX, EX and ST)
2
MC9S12XDP512 Data Sheet, Rev. 2.21
636
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
CPU and BDM
Local Memory Map
Global Memory Map
$00_0000
2K Registers
$00_0800
CS3
Unimplemented
RAM
2K Registers
RAM
$0800
EEPROM
1K window
EPAGE
RAMSIZE
$0000
$0F_FFFF
$0C00
$2000
EEPROM
$13_FFFF
8K RAM
$1F_FFFF
CS1
External
Space
$4000
CS2
RPAGE
EEPROMSIZE
Unimplemented
EEPROM
$1000
RAM
4K window
CS2
1K EEPROM
Unpaged Flash
$40_0000
Flash
16K window
CS0
$8000
Unimplemented
FLASH
PPAGE
$C000
$FFFF
Reset Vectors
FLASH
FLASHSIZE
Unpaged Flash
$7F_FFFF
Figure 17-23. Local to Implemented Global Address Mapping (Without GPAGE)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
637
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.4.2.4
17.4.2.4.1
XGATE Memory Map Scheme
Expansion of the XGATE Local Address Map
The XGATE 64 Kbyte memory space allows access to internal resources only (Registers, RAM, and
FLASH). The 2 Kilobyte register address range is the same register address range as for the CPU and the
BDM module . XGATE can access the FLASH in single chip modes, even when the MCU is secured. In
expanded modes, XGATE can not access the FLASH when MCU is secured.
The local address of the XGATE RAM access is translated to the global RAM address range. The XGATE
shares the RAM resource with the CPU and the BDM module. The local address of the XGATE FLASH
access is translated to the global address as shown in Figure 17-24. For the implemented memory spaces
and addresses please refer to Table 1-4 and Table 1-5.
MC9S12XDP512 Data Sheet, Rev. 2.21
638
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
XGATE
Local Memory Map
Global Memory Map
$00_0000
2K Registers
$00_0800
$0800
RAM
$0F_FFFF
XGRAMSIZE
2K Registers
RAMSIZE
$0000
RAM
$FFFF
FLASH
FLASHSIZE
2K
XGRAMSIZE
FLASH
$7F_FFFF
Figure 17-24. Local to Global Address Mapping (XGATE)
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
639
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.4.3
17.4.3.1
Chip Access Restrictions
Illegal XGATE Accesses
A possible access error is flagged by the MMC and signalled to XGATE under the following conditions:
• XGATE performs misaligned word (in case of load-store or opcode or vector fetch accesses).
• XGATE accesses the register space (in case of opcode or vector fetch).
• XGATE performs a write to Flash in any modes (in case of load-store access).
• XGATE performs an access to a secured Flash in expanded modes (in case of load-store or opcode
or vector fetch accesses).
• XGATE performs a write to non-XGATE region in RAM (RAM protection mechanism) (in case
of load-store access).
For further details refer to the XGATE Block Guide.
17.4.3.2
Illegal CPU Accesses
After programming the protection mechanism registers (see Figure 1-17, Figure 1-18, Figure 1-19, and
Figure 1-20) and setting the RWPE bit (see Figure 1-17) there are 3 regions recognized by the MMC
module:
1. XGATE RAM region
2. CPU RAM region
3. Shared Region (XGATE AND CPU)
If the RWPE bit is set the CPU write accesses into the XGATE RAM region are blocked. If the CPU tries
to write the XGATE RAM region the AVIF bit is set and an interrupt is generated if enabled. Furthermore
if the XGATE tries to write to outside of the XGATE RAM or shared regions and the RWPE bit is set, the
write access is suppressed and the access error will be flagged to the XGATE module (see Section 1.4.3.1,
“Illegal XGATE Accesses” and the XGATE Block Guide).
The bottom address of the XGATE RAM region always starts at the lowest implemented RAM address.
The values stored in the boundary registers define the boundary addresses in 256 byte steps. The 256 byte
block selected by any of the registers is always included in the respective region. For example setting the
shared region lower boundary register (RAMSHL) to $C1 and the shared region upper boundary register
(RAMSHU) to $E0 defines the shared region from address $0F_C100 to address $0F_E0FF in the global
memory space (see Figure 1-25).
The interrupt requests generated by the MMC are listed in Table 1-23. Refer to the Device User Guide for
the related interrupt vector address and interrupt priority.
MC9S12XDP512 Data Sheet, Rev. 2.21
640
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
The following conditions must be satisfied to ensure correct operation of the RAM protection mechanism:
• Value stored in RAMXGU must be lower than the value stored in RAMSHL.
• Value stored RAMSHL must be lower or equal than the value stored in RAMSHU.
Table 17-21. RAM Write Protection Interrupt Vectors
Interrupt Source
CCR Mask
Local Enable
CPU access violation
I Bit
AVIE in RAMWPC
$00_0000
2K Registers
$00_0800
Unimplemented
XGATE RAM
Region
Only XGATE is allowed to write
$0F_RAMXGU_FF
RAMSIZE
Only CPU is allowed to write
$0F_RAMSHL_00
Shared Region
CPU and XGATE are allowed to write
$0F_RAMSHU_FF
Only CPU is allowed to write
$0F_FFFF
Figure 17-25. RAM Write Protection Scheme
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
641
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.4.4
Chip Bus Control
The MMC controls the address buses and the data buses that interface the S12X masters (CPU, BDM and
XGATE) with the rest of the system (master buses). In addition the MMC handles all CPU read data bus
swapping operations. All internal and external resources are connected to specific target buses (see
Figure 1-26).
BDM
S12X
CPU
XGATE
XGATE
S12X
MMC
XRAM
XBus2
XBus1
BDM
ROM/REG
EBI
RAM
XBus0
XEEPROM
XFLASH
IPBI
P3
P2
P1
P0
IO
2 Kbyte Registers
Figure 17-26. S12X Architecture
17.4.4.1
Master Bus Prioritization
The following rules apply when prioritizing accesses over master buses:
• The CPU has priority over the BDM, unless the BDM access is stalled for more than 128 cycles.
In the later case the CPU will be stalled after finishing the current operation and the BDM will gain
access to the bus.
• XGATE access to PRU registers constitutes a special case. It is always granted and stalls the CPU
and BDM for its duration.
MC9S12XDP512 Data Sheet, Rev. 2.21
642
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.4.4.2
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 XGATE.
• BDM access has priority over XGATE.
• XGATE access to PRU registers constitutes a special case. It is always granted and stalls the CPU
and BDM for its duration.
• In emulation modes all internal accesses are visible on the external bus as well.
• During access to the PRU registers, the external bus is reserved.
17.4.5
Interrupts
17.4.5.1
Outgoing Interrupt Requests
The following interrupt requests can be triggered by the MMC module:
CPU access violation: The CPU access violation signals to the CPU detection of an error condition in the
CPU application code which is resulted in write access to the protected XGATE RAM area (see
Section 1.4.3.2, “Illegal CPU Accesses”).
17.5
17.5.1
Initialization/Application Information
CALL and RTC Instructions
CALL and RTC instructions are uninterruptable 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 16 Kbyte program page window in the
64 Kbyte 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
instruction-supplied 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
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
643
Chapter 17 Memory Mapping Control (S12XMMCV2)
This sequence is uninterruptable. 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.
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 uninterruptable. 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.
17.5.2
Port Replacement Registers (PRRs)
Registers used for emulation purposes must be rebuilt by the in-circuit emulator hardware to achieve full
emulation of single chip mode operation. These registers are called port replacement registers (PRRs) (see
Table 1-25). PRRs are accessible from all masters using different access types (word aligned,
word-misaligned and byte). Each access to PRRs will be extended to 2 bus cycles for write or read accesses
independent of the operating mode. In emulation modes all write operations result in writing into the
internal registers (peripheral access) and into the emulated registers (external access) located in the PRU
in the emulator at the same time. All read operations are performed from external registers (external
access) in emulation modes. In all other modes the read operations are performed from the internal
registers (peripheral access).
MC9S12XDP512 Data Sheet, Rev. 2.21
644
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
Due to internal visibility of CPU accesses the CPU will be halted during XGATE or BDM access to any
PRR. This rule applies also in normal modes to ensure that operation of the device is the same as in
emulation modes.
A summary of PRR accesses is the following:
• An aligned word access to a PRR will take 2 bus cycles.
• A misaligned word access to a PRRs will take 4 cycles. If one of the two bytes accessed by the
misaligned word access is not a PRR, the access will take only 3 cycles.
• A byte access to a PRR will take 2 cycles.
Table 17-22. PRR Listing
PRR Name
PRR Local Address
PRR Location
PORTA
$0000
PIM
PORTB
$0001
PIM
DDRA
$0002
PIM
DDRB
$0003
PIM
PORTC
$0004
PIM
PORTD
$0005
PIM
DDRC
$0006
PIM
DDRD
$0007
PIM
PORTE
$0008
PIM
DDRE
$0009
PIM
MMCCTL0
$000A
MMC
MODE
$000B
MMC
PUCR
$000C
PIM
RDRIV
$000D
PIM
EBICTL0
$000E
EBI
EBICTL1
$000F
EBI
Reserved
$0012
MMC
MMCCTL1
$0013
MMC
ECLKCTL
$001C
PIM
Reserved
$001D
PIM
PORTK
$0032
PIM
DDRK
$0033
PIM
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
645
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.5.3
On-Chip ROM Control
The MCU offers two modes to support emulation. In the first mode (called generator) the emulator
provides the data instead of the internal FLASH and traces the CPU actions. In the other mode (called
observer) the internal FLASH provides the data and all internal actions are made visible to the emulator.
17.5.3.1
ROM Control in Single-Chip Modes
In single-chip modes the MCU has no external bus. All memory accesses and program fetches are internal
(see Figure 1-27).
MCU
No External Bus
Flash
Figure 17-27. ROM in Single Chip Modes
17.5.3.2
ROM Control in Emulation Single-Chip Mode
In emulation single-chip mode the external bus is connected to the emulator. If the EROMON bit is set,
the internal FLASH provides the data and the emulator can observe all internal CPU actions on the external
bus. If the EROMON bit is cleared, the emulator provides the data (generator) and traces the all CPU
actions (see Figure 1-28).
Observer
MCU
Emulator
Flash
EROMON = 1
Generator
MCU
Emulator
Flash
EROMON = 0
Figure 17-28. ROM in Emulation Single-Chip Mode
MC9S12XDP512 Data Sheet, Rev. 2.21
646
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.5.3.3
ROM Control in Normal Expanded Mode
In normal expanded mode the external bus will be connected to the application. If the ROMON bit is set,
the internal FLASH provides the data. If the ROMON bit is cleared, the application memory provides the
data (see Figure 1-29).
MCU
Application
Flash
Memory
ROMON = 1
MCU
Application
Memory
ROMON = 0
Figure 17-29. ROM in Normal Expanded Mode
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
647
Chapter 17 Memory Mapping Control (S12XMMCV2)
17.5.3.4
ROM Control in Emulation Expanded Mode
In emulation expanded mode the external bus will be connected to the emulator and to the application. If
the ROMON bit is set, the internal FLASH provides the data. If the EROMON bit is set as well the
emulator observes all CPU internal actions, otherwise the emulator provides the data and traces all CPU
actions (see Figure 1-30). When the ROMON bit is cleared, the application memory provides the data and
the emulator will observe the CPU internal actions (see Figure 1-31).
Observer
MCU
Emulator
Flash
Application
Memory
EROMON = 1
Generator
MCU
Emulator
Flash
Application
Memory
EROMON = 0
Figure 17-30. ROMON = 1 in Emulation Expanded Mode
MC9S12XDP512 Data Sheet, Rev. 2.21
648
Freescale Semiconductor
Chapter 17 Memory Mapping Control (S12XMMCV2)
Observer
MCU
Emulator
Application
Memory
Figure 17-31. ROMON = 0 in Emulation Expanded Mode
17.5.3.5
ROM Control in Special Test Mode
In special test mode the external bus is connected to the application. If the ROMON bit is set, the internal
FLASH provides the data, otherwise the application memory provides the data (see Figure 1-32).
Application
MCU
Memory
ROMON = 0
Application
MCU
Flash
Memory
ROMON = 1
Figure 17-32. ROM in Special Test Mode
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
649
Chapter 17 Memory Mapping Control (S12XMMCV2)
MC9S12XDP512 Data Sheet, Rev. 2.21
650
Freescale Semiconductor
Chapter 18
Memory Mapping Control (S12XMMCV3)
18.1
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 18-1.
The MMC module controls the multi-master priority accesses, the selection of internal resources and
external space. 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
651
Chapter 18 Memory Mapping Control (S12XMMCV3)
18.1.1
Terminology
Table 18-1. Acronyms and Abbreviations
Logic level “1”
Voltage that corresponds to Boolean true state
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 64 KBytes Memory Space (16-bit address)
global address
based on the 8 MBytes Memory Space (23-bit address)
Aligned address
Address on even boundary
Mis-aligned address
Address on odd boundary
Bus Clock
System Clock. Refer to CRG Block Guide.
expanded modes
Normal Expanded Mode
Emulation Single-Chip Mode
Emulation Expanded Mode
Special Test Mode
single-chip modes
Normal Single-Chip Mode
Special Single-Chip Mode
emulation modes
Emulation Single-Chip Mode
Emulation Expanded Mode
normal modes
Normal Single-Chip Mode
Normal Expanded Mode
special modes
Special Single-Chip Mode
Special Test Mode
NS
Normal Single-Chip Mode
SS
Special Single-Chip Mode
NX
Normal Expanded Mode
ES
Emulation Single-Chip Mode
EX
Emulation Expanded Mode
ST
Special Test Mode
Unimplemented areas
External Space
external resource
18.1.2
Areas which are accessible by the pages (RPAGE,PPAGE,EPAGE) and not implemented