SILABS C8051F537-IT

C8051F52x-53x
8/4/2 kB ISP Flash MCU Family
•
•
•
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±1 LSB INL (C8051F52x/C8051F53x); no missing
codes
Programmable throughput up to 200 ksps
Up to 6/16 external inputs
Data dependent windowed interrupt generator
Built-in temperature sensor
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Programmable hysteresis and response time
Configurable as wake-up or reset source
Low current
•
-
Comparator
- POR/Brownout Detector
- Voltage Reference—1.5 to 2.2 V (programmable)
On-Chip Debug
- On-chip debug circuitry facilitates full-speed, nonintrusive in-system debug (No emulator required)
Provides breakpoints, single stepping
Inspect/modify memory and registers
Complete development kit
Supply Voltage 2.7 to 5.25 V
- Built-in LDO regulator
High Speed 8051 µC Core
- Pipelined instruction architecture; executes 70% of
-
instructions in 1 or 2 system clocks
Up to 25 MIPS throughput with
25 MHz system clock
Expanded interrupt handler
ANALOG
PERIPHERALS
A
M
U
X
12-bit
200 ksps
ADC
TEMP
SENSOR
+
VOLTAGE
COMPARATOR
VREF
Memory
- 8/4/2 kB Flash; In-system byte programmable in
512 byte sectors
- 256 bytes internal data RAM
Digital Peripherals
- 16/6 port I/O; push-pull or open-drain, 5 V tolerant
- Hardware SPI™, and UART serial port
- Hardware LIN (both master and slave, compatible
-
with V1.3 and V2.0)
Three general purpose 16-bit counter/timers
Programmable 16-bit counter/timer array with three
capture/compare modules, WDT
Clock Sources
- Internal oscillators: 24.5 MHz ±0.5% accuracy sup-
ports UART and LIN-Master operation
External oscillator: Crystal, RC, C, or Clock
(1 or 2 pin modes)
Can switch between clock sources on-the-fly
Packages:
- 10-Pin QFN (3 x 3 mm)
- 20-pin QFN (4 x 4 mm)
- 20-pin TSSOP
Temperature Range: –40 to +125 °C
DIGITAL I/O
UART
SPI
PCA
Timer 0
Timer 1
Timer 2
Port 0
CROSSBAR
Analog Peripherals
- 12-Bit ADC
Port 1
LIN
VREG
24.5 MHz High Precision (±0.5%) Internal Oscillator
HIGH-SPEED CONTROLLER CORE
8/4/2 kB
ISP FLASH
FLEXIBLE
INTERRUPTS
Rev. 0.3 5/07
8051 CPU
(25 MIPS)
DEBUG
CIRCUITRY
256 B SRAM
POR
Copyright © 2007 by Silicon Laboratories
WDT
C8051F52x-53x
C8051F52x-53x
NOTES:
2
Rev. 0.3
C8051F52x-53x
Table of Contents
1. System Overview.................................................................................................... 17
1.1. CIP-51™ Microcontroller................................................................................... 21
1.1.1. Fully 8051 Compatible Instruction Set...................................................... 21
1.1.2. Improved Throughput ............................................................................... 21
1.1.3. Additional Features .................................................................................. 21
1.1.4. On-Chip Debug Circuitry .......................................................................... 21
1.2. On-Chip Memory............................................................................................... 22
1.3. Operating Modes .............................................................................................. 24
1.4. 12-Bit Analog to Digital Converter..................................................................... 25
1.5. Programmable Comparator .............................................................................. 26
1.6. Voltage Regulator ............................................................................................. 26
1.7. Serial Port ......................................................................................................... 26
1.8. Port Input/Output............................................................................................... 27
2. Absolute Maximum Ratings .................................................................................. 29
3. Global DC Electrical Characteristics .................................................................... 30
4. Pinout and Package Definitions............................................................................ 31
5. 12-Bit ADC (ADC0).................................................................................................. 41
5.1. Analog Multiplexer ............................................................................................ 41
5.2. Temperature Sensor ......................................................................................... 42
5.3. ADC0 Operation................................................................................................ 42
5.3.1. Starting a Conversion............................................................................... 43
5.3.2. Tracking Modes........................................................................................ 43
5.3.3. Timing....................................................................................................... 44
5.3.4. Burst Mode ............................................................................................... 46
5.3.5. Output Conversion Code.......................................................................... 47
5.3.6. Settling Time Requirements ..................................................................... 48
5.4. Programmable Window Detector ...................................................................... 53
5.4.1. Window Detector In Single-Ended Mode ................................................. 56
5.5. Selectable Attenuation ...................................................................................... 57
5.6. Typical ADC Parameters and Description ........................................................ 57
5.6.1. Resolution ................................................................................................ 57
5.6.2. Integral Non-Linearity (INL) ...................................................................... 57
5.6.3. Differential Non-Linearity (DNL) ............................................................... 57
5.6.4. Offset ....................................................................................................... 58
5.6.5. Full-Scale ................................................................................................. 58
5.6.6. Signal to Noise Plus Distortion ................................................................. 58
5.6.7. Total Harmonic Distortion (THD) .............................................................. 59
5.6.8. Spurious Free Dynamic Range (SFDR) ................................................... 59
6. Voltage Reference .................................................................................................. 63
7. Voltage Regulator (REG0)...................................................................................... 67
8. Comparator ........................................................................................................... 69
9. CIP-51 Microcontroller ........................................................................................... 75
9.1. Instruction Set ................................................................................................... 76
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3
C8051F52x-53x
9.1.1. Instruction and CPU Timing ..................................................................... 76
9.1.2. MOVX Instruction and Program Memory ................................................. 77
9.2. Register Descriptions........................................................................................ 80
9.3. Power Management Modes .............................................................................. 83
9.3.1. Idle Mode.................................................................................................. 84
9.3.2. Stop Mode ................................................................................................ 84
10. Memory Organization and SFRs ........................................................................... 85
10.1.Program Memory.............................................................................................. 85
10.2.Data Memory .................................................................................................... 86
10.3.General Purpose Registers .............................................................................. 86
10.4.Bit Addressable Locations ................................................................................ 86
10.5.Stack................................................................................................................. 86
10.6.Special Function Registers............................................................................... 87
11. Interrupt Handler .................................................................................................... 91
11.1.MCU Interrupt Sources and Vectors................................................................. 91
11.2.Interrupt Priorities ............................................................................................. 91
11.3.Interrupt Latency............................................................................................... 91
11.4.Interrupt Register Descriptions ......................................................................... 93
11.5.External Interrupts ............................................................................................ 97
12. Reset Sources......................................................................................................... 99
12.1.Power-On Reset ............................................................................................. 100
12.2.Power-Fail Reset / VDD Monitor .................................................................... 101
12.3.External Reset ................................................................................................ 102
12.4.Missing Clock Detector Reset ........................................................................ 102
12.5.Comparator Reset .......................................................................................... 102
12.6.PCA Watchdog Timer Reset .......................................................................... 103
12.7.Flash Error Reset ........................................................................................... 103
12.8.Software Reset ............................................................................................... 103
13. Flash Memory ....................................................................................................... 107
13.1.Programming The Flash Memory ................................................................... 107
13.1.1.Flash Lock and Key Functions ............................................................... 107
13.1.2.Flash Erase Procedure .......................................................................... 108
13.1.3.Flash Write Procedure ........................................................................... 108
13.2.Flash Write and Erase Guidelines .................................................................. 109
13.2.1.VDD Maintenance and the VDD monitor ................................................. 110
13.2.2.PSWE Maintenance ............................................................................... 111
13.2.3.System Clock ......................................................................................... 111
13.3.Non-volatile Data Storage .............................................................................. 112
13.4.Security Options ............................................................................................. 112
14. Port Input/Output.................................................................................................. 117
14.1.Priority Crossbar Decoder .............................................................................. 119
14.2.Port I/O Initialization ....................................................................................... 123
14.3.General Purpose Port I/O ............................................................................... 125
15. Oscillators ............................................................................................................. 133
15.1.Programmable Internal Oscillator ................................................................... 133
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C8051F52x-53x
15.1.1.Internal Oscillator Suspend Mode .......................................................... 134
15.2.External Oscillator Drive Circuit...................................................................... 137
15.2.1.Clocking Timers Directly Through the External Oscillator...................... 137
15.2.2.External Crystal Example....................................................................... 137
15.2.3.External RC Example............................................................................. 139
15.2.4.External Capacitor Example................................................................... 139
15.3.System Clock Selection.................................................................................. 141
16. UART0.................................................................................................................... 143
16.1.Enhanced Baud Rate Generation................................................................... 144
16.2.Operational Modes ......................................................................................... 145
16.2.1.8-Bit UART ............................................................................................. 145
16.2.2.9-Bit UART ............................................................................................. 146
16.3.Multiprocessor Communications .................................................................... 146
17. LIN (C8051F520/523/526/530/533/536 only) ........................................................ 151
17.1.Major Characteristics...................................................................................... 151
17.2. Software Interface with the LIN Peripheral .................................................. 152
17.3.LIN Registers.................................................................................................. 153
17.3.1.LIN Direct Access SFR Registers Definition .......................................... 153
17.3.2.LIN Indirect Access SFR Registers Definition........................................ 154
17.4.LIN Interface Setup and Operation................................................................. 161
17.4.1.Mode Definition ...................................................................................... 161
17.4.2.Bit Rate Options: Manual or Autobaud (Slave only)............................... 162
17.4.3.Baud Rate Calculations - Manual Mode................................................. 162
17.4.4.Baud Rate Calculations - Automatic Mode ............................................ 164
17.4.5.LIN Master Mode Operation................................................................... 165
17.4.6.LIN Slave Mode Operation..................................................................... 166
17.4.7.Sleep Mode and Wake-Up ..................................................................... 167
17.4.8.Error Detection and Handling................................................................. 168
17.4.9.LIN Master Mode Operation................................................................... 168
17.4.10.LIN Slave Mode Operation................................................................... 168
18. Enhanced Serial Peripheral Interface (SPI0)...................................................... 171
18.1.Signal Descriptions......................................................................................... 172
18.1.1.Master Out, Slave In (MOSI).................................................................. 172
18.1.2.Master In, Slave Out (MISO).................................................................. 172
18.1.3.Serial Clock (SCK) ................................................................................. 172
18.1.4.Slave Select (NSS) ................................................................................ 172
18.2.SPI0 Master Mode Operation ......................................................................... 173
18.3.SPI0 Slave Mode Operation ........................................................................... 174
18.4.SPI0 Interrupt Sources ................................................................................... 175
18.5.Serial Clock Timing......................................................................................... 175
18.6.SPI Special Function Registers ...................................................................... 176
19. Timers.................................................................................................................... 185
19.1.Timer 0 and Timer 1 ....................................................................................... 185
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5
C8051F52x-53x
19.1.1.Mode 0: 13-bit Counter/Timer ................................................................ 185
19.1.2.Mode 1: 16-bit Counter/Timer ................................................................ 187
19.1.3.Mode 2: 8-bit Counter/Timer with Auto-Reload...................................... 187
19.1.4.Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)................................. 188
19.2.Timer 2 .......................................................................................................... 193
19.2.1.16-bit Timer with Auto-Reload................................................................ 193
19.2.2.8-bit Timers with Auto-Reload................................................................ 194
19.2.3.External Capture Mode .......................................................................... 195
20. Programmable Counter Array (PCA0) ................................................................ 199
20.1.PCA Counter/Timer ........................................................................................ 200
20.2.Capture/Compare Modules ............................................................................ 201
20.2.1.Edge-triggered Capture Mode................................................................ 202
20.2.2.Software Timer (Compare) Mode........................................................... 203
20.2.3.High Speed Output Mode....................................................................... 204
20.2.4.Frequency Output Mode ........................................................................ 205
20.2.5.8-Bit Pulse Width Modulator Mode......................................................... 206
20.2.6.16-Bit Pulse Width Modulator Mode....................................................... 207
20.3.Watchdog Timer Mode ................................................................................... 207
20.3.1.Watchdog Timer Operation .................................................................... 208
20.3.2.Watchdog Timer Usage ......................................................................... 209
20.4.Register Descriptions for PCA........................................................................ 211
21. Revision Specific Behavior ................................................................................. 215
21.1.Revision Identification..................................................................................... 215
21.2.Reset Behavior ............................................................................................... 216
21.3.UART Pins...................................................................................................... 216
21.4.LIN .................................................................................................................. 216
21.4.1.Stop Bit Check ....................................................................................... 216
21.4.2.Synch Break and Synch Field Length Check......................................... 216
22. C2 Interface ........................................................................................................... 217
22.1.C2 Interface Registers.................................................................................... 217
22.2.C2 Pin Sharing ............................................................................................... 219
Contact Information.................................................................................................. 220
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C8051F52x-53x
List of Figures
1. System Overview
Figure 1.1. C8051F530 Block Diagram .................................................................... 19
Figure 1.2. C8051F520 Block Diagram .................................................................... 20
Figure 1.3. Development/In-System Debug Diagram............................................... 22
Figure 1.4. Memory Map .......................................................................................... 23
Figure 1.5. 12-Bit ADC Block Diagram..................................................................... 25
Figure 1.6. Comparator Block Diagram.................................................................... 26
Figure 1.7. Port I/O Functional Block Diagram......................................................... 27
2. Absolute Maximum Ratings
3. Global DC Electrical Characteristics
4. Pinout and Package Definitions
Figure 4.1. TSSOP-20 Package Diagram ................................................................ 37
Figure 4.2. QFN-20 Package Diagram..................................................................... 38
Figure 4.3. QFN-10 Package Diagram..................................................................... 39
5. 12-Bit ADC (ADC0)
Figure 5.1. ADC0 Functional Block Diagram............................................................ 41
Figure 5.2. Typical Temperature Sensor Transfer Function..................................... 42
Figure 5.3. ADC0 Tracking Modes ........................................................................... 44
Figure 5.4. 12-Bit ADC Tracking Mode Example ..................................................... 45
Figure 5.5. 12-Bit ADC Burst Mode Example with Repeat Count Set to 4............... 46
Figure 5.6. ADC0 Equivalent Input Circuits.............................................................. 48
Figure 5.7. ADC Window Compare Example: Right-Justified Single-Ended Data ... 56
Figure 5.8. ADC Window Compare Example: Left-Justified Single-Ended Data ..... 56
6. Voltage Reference
Figure 6.1. Voltage Reference Functional Block Diagram ....................................... 63
7. Voltage Regulator (REG0)
Figure 7.1. External Capacitors for Voltage Regulator Input/Output ........................ 67
8. Comparator
Figure 8.1. Comparator Functional Block Diagram .................................................. 69
Figure 8.2. Comparator Hysteresis Plot ................................................................... 70
9. CIP-51 Microcontroller
Figure 9.1. CIP-51 Block Diagram............................................................................ 75
10. Memory Organization and SFRs
Figure 10.1. Memory Map ........................................................................................ 85
11. Interrupt Handler
12. Reset Sources
Figure 12.1. Reset Sources...................................................................................... 99
Figure 12.2. Power-On and VDD Monitor Reset Timing ......................................... 100
13. Flash Memory
Figure 13.1. Flash Program Memory Map.............................................................. 112
14. Port Input/Output
Figure 14.1. Port I/O Functional Block Diagram ..................................................... 117
Figure 14.2. Port I/O Cell Block Diagram ............................................................... 118
Rev. 0.3
7
C8051F52x-53x
Figure 14.3. Crossbar Priority Decoder with No Pins Skipped
(TSSOP 20 and QFN 20) .................................................................................. 119
Figure 14.4. Crossbar Priority Decoder with Crystal Pins Skipped
(TSSOP 20 and QFN 20) .................................................................................. 120
Figure 14.5. Crossbar Priority Decoder with No Pins Skipped (QFN 10) ............... 121
Figure 14.6. Crossbar Priority Decoder with Crystal Pins Skipped (QFN 10) ........ 122
15. Oscillators
Figure 15.1. Oscillator Diagram.............................................................................. 133
Figure 15.2. 32 kHz External Crystal Example....................................................... 138
16. UART0
Figure 16.1. UART0 Block Diagram ....................................................................... 143
Figure 16.2. UART0 Baud Rate Logic .................................................................... 144
Figure 16.3. UART Interconnect Diagram .............................................................. 145
Figure 16.4. 8-Bit UART Timing Diagram............................................................... 145
Figure 16.5. 9-Bit UART Timing Diagram............................................................... 146
Figure 16.6. UART Multi-Processor Mode Interconnect Diagram .......................... 147
17. LIN (C8051F520/523/526/530/533/536 only)
Figure 17.1. LIN Flowchart ..................................................................................... 151
18. Enhanced Serial Peripheral Interface (SPI0)
Figure 18.1. SPI Block Diagram ............................................................................. 171
Figure 18.2. Multiple-Master Mode Connection Diagram ....................................... 174
Figure 18.3. 3-Wire Single Master and Slave Mode Connection Diagram ............. 174
Figure 18.4. 4-Wire Single Master and Slave Mode Connection Diagram ............. 174
Figure 18.5. Data/Clock Timing Relationship ......................................................... 176
Figure 18.6. SPI Master Timing (CKPHA = 0)........................................................ 181
Figure 18.7. SPI Master Timing (CKPHA = 1)........................................................ 181
Figure 18.8. SPI Slave Timing (CKPHA = 0).......................................................... 182
Figure 18.9. SPI Slave Timing (CKPHA = 1).......................................................... 182
19. Timers
Figure 19.1. T0 Mode 0 Block Diagram.................................................................. 186
Figure 19.2. T0 Mode 2 Block Diagram.................................................................. 187
Figure 19.3. T0 Mode 3 Block Diagram.................................................................. 188
Figure 19.4. Timer 2 16-Bit Mode Block Diagram .................................................. 193
Figure 19.5. Timer 2 8-Bit Mode Block Diagram .................................................... 194
Figure 19.6. Timer 2 Capture Mode Block Diagram ............................................... 195
20. Programmable Counter Array (PCA0)
Figure 20.1. PCA Block Diagram............................................................................ 199
Figure 20.2. PCA Counter/Timer Block Diagram.................................................... 200
Figure 20.3. PCA Interrupt Block Diagram ............................................................. 201
Figure 20.4. PCA Capture Mode Diagram.............................................................. 202
Figure 20.5. PCA Software Timer Mode Diagram .................................................. 203
Figure 20.6. PCA High-Speed Output Mode Diagram............................................ 204
Figure 20.7. PCA Frequency Output Mode ............................................................ 205
Figure 20.8. PCA 8-Bit PWM Mode Diagram ......................................................... 206
Figure 20.9. PCA 16-Bit PWM Mode...................................................................... 207
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Rev. 0.3
C8051F52x-53x
Figure 20.10. PCA Module 2 with Watchdog Timer Enabled ................................. 208
21. Revision Specific Behavior
Figure 21.1. Device Package - TSSOP 20 ............................................................. 215
Figure 21.2. Device Package - QFN 20.................................................................. 215
Figure 21.3. Device Package - QFN 10.................................................................. 216
22. C2 Interface
Figure 22.1. Typical C2 Pin Sharing....................................................................... 219
Rev. 0.3
9
C8051F52x-53x
NOTES:
10
Rev. 0.3
C8051F52x-53x
List of Tables
1. System Overview
Table 1.1. Product Selection Guide ......................................................................... 18
Table 1.2. Operating Modes Summary .................................................................... 24
2. Absolute Maximum Ratings
Table 2.1.Absolute Maximum Ratings..................................................................... 29
3. Global DC Electrical Characteristics
Table 3.1.Global DC Electrical Characteristics........................................................ 30
4. Pinout and Package Definitions
Table 4.1. Pin Definitions for the C8051F520 (QFN 10) .......................................... 31
Table 4.2. Pin Definitions for the C8051F530 (TSSOP 20) ..................................... 33
Table 4.3. Pin Definitions for the C8051F530 (QFN 20) .......................................... 35
Table 4.4. TSSOP-20 Package Diagram Dimensions ............................................. 37
Table 4.5. QFN-20 Package Diagram Dimensions ................................................. 38
Table 4.6. QFN-10 Package Diagram Dimensions ................................................. 39
5. 12-Bit ADC (ADC0)
Table 5.1.ADC0 Electrical Characteristics (VDD = 2.6 V, VREF = 1.5 V) ................. 60
Table 5.2.ADC0 Electrical Characteristics (VDD = 2.1 V, VREF = 1.5 V) ................. 61
6. Voltage Reference
Table 6.1.Voltage Reference Electrical Characteristics .......................................... 65
7. Voltage Regulator (REG0)
Table 7.1.Voltage Regulator Electrical Specifications ............................................. 68
8. Comparator
Table 8.1.Comparator Electrical Characteristics ..................................................... 74
9. CIP-51 Microcontroller
Table 9.1. CIP-51 Instruction Set Summary ............................................................ 77
10. Memory Organization and SFRs
Table 10.1. Special Function Register (SFR) Memory Map .................................... 87
Table 10.2. Special Function Registers ................................................................... 88
11. Interrupt Handler
Table 11.1. Interrupt Summary ................................................................................ 92
12. Reset Sources
Table 12.1.Reset Electrical Characteristics........................................................... 105
13. Flash Memory
Table 13.1. Flash Security Summary .................................................................... 114
Table 13.2.Flash Electrical Characteristics ........................................................... 116
14. Port Input/Output
Table 14.1.Port I/O DC Electrical Characteristics.................................................. 132
15. Oscillators
Table 15.1.Oscillator Electrical Characteristics ..................................................... 142
Table 15.2.Oscillator Wake-Up Time from Suspend Mode ................................... 142
16. UART0
Table 16.1. Timer Settings for Standard Baud Rates
Using the Internal Oscillator ............................................................... 150
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11
C8051F52x-53x
17. LIN (C8051F520/523/526/530/533/536 only)
Table 17.1. LIN Registers (Indirectly Addressable) ............................................... 154
Table 17.2. Table Needs Title ............................................................................... 162
Table 17.3. Manual Bit-Rate Parameters Examples ............................................. 164
Table 17.4. Autobaud Parameters Examples ........................................................ 165
18. Enhanced Serial Peripheral Interface (SPI0)
Table 18.1. SPI Slave Timing Parameters ............................................................ 183
19. Timers
20. Programmable Counter Array (PCA0)
Table 20.1. PCA Timebase Input Options ............................................................. 200
Table 20.2. PCA0CPM Register Settings for PCA Capture/Compare Modules .... 201
Table 20.3. Watchdog Timer Timeout Intervals ..................................................... 210
21. Revision Specific Behavior
22. C2 Interface
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C8051F52x-53x
List of Registers
SFR Definition 5.1. ADC0MX: ADC0 Channel Select . . . . . . . . . . . . . . . . . . . . . . . . . . 49
SFR Definition 5.2. ADC0CF: ADC0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
SFR Definition 5.3. ADC0H: ADC0 Data Word MSB . . . . . . . . . . . . . . . . . . . . . . . . . . 51
SFR Definition 5.4. ADC0L: ADC0 Data Word LSB . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
SFR Definition 5.5. ADC0CN: ADC0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
SFR Definition 5.6. ADC0TK: ADC0 Tracking Mode Select . . . . . . . . . . . . . . . . . . . . 53
SFR Definition 5.7. ADC0GTH: ADC0 Greater-Than Data High Byte . . . . . . . . . . . . . 54
SFR Definition 5.8. ADC0GTL: ADC0 Greater-Than Data Low Byte . . . . . . . . . . . . . . 54
SFR Definition 5.9. ADC0LTH: ADC0 Less-Than Data High Byte . . . . . . . . . . . . . . . . 55
SFR Definition 5.10. ADC0LTL: ADC0 Less-Than Data Low Byte . . . . . . . . . . . . . . . . 55
SFR Definition 6.1. REF0CN: Reference Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
SFR Definition 7.1. REG0CN: Regulator Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
SFR Definition 8.1. CPT0CN: Comparator0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
SFR Definition 8.2. CPT0MX: Comparator0 MUX Selection . . . . . . . . . . . . . . . . . . . . 72
SFR Definition 8.3. CPT0MD: Comparator0 Mode Selection . . . . . . . . . . . . . . . . . . . . 73
SFR Definition 9.1. SP: Stack Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
SFR Definition 9.2. DPL: Data Pointer Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
SFR Definition 9.3. DPH: Data Pointer High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
SFR Definition 9.4. PSW: Program Status Word . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
SFR Definition 9.5. ACC: Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
SFR Definition 9.6. B: B Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
SFR Definition 9.7. PCON: Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
SFR Definition 11.1. IE: Interrupt Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
SFR Definition 11.2. IP: Interrupt Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
SFR Definition 11.3. EIE1: Extended Interrupt Enable 1 . . . . . . . . . . . . . . . . . . . . . . . 95
SFR Definition 11.4. EIP1: Extended Interrupt Priority 1 . . . . . . . . . . . . . . . . . . . . . . . 96
SFR Definition 11.5. IT01CF: INT0/INT1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . 98
SFR Definition 12.1. VDDMON: VDD Monitor Control . . . . . . . . . . . . . . . . . . . . . . . . 102
SFR Definition 12.2. RSTSRC: Reset Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
SFR Definition 13.1. PSCTL: Program Store R/W Control . . . . . . . . . . . . . . . . . . . . . 115
SFR Definition 13.2. FLKEY: Flash Lock and Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
SFR Definition 14.1. XBR0: Port I/O Crossbar Register 0 . . . . . . . . . . . . . . . . . . . . . 124
SFR Definition 14.2. XBR1: Port I/O Crossbar Register 1 . . . . . . . . . . . . . . . . . . . . . 125
SFR Definition 14.3. P0: Port0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
SFR Definition 14.4. P0MDIN: Port0 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
SFR Definition 14.5. P0MDOUT: Port0 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . . 127
SFR Definition 14.6. P0SKIP: Port0 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
SFR Definition 14.7. P0MAT: Port0 Match . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
SFR Definition 14.8. P0MASK: Port0 Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
SFR Definition 14.9. P1: Port1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
SFR Definition 14.10. P1MDIN: Port1 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
SFR Definition 14.11. P1MDOUT: Port1 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . 130
SFR Definition 14.12. P1SKIP: Port1 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Rev. 0.3
13
C8051F52x-53x
SFR Definition 14.13. P0SKIP: Port0 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
SFR Definition 14.14. P1MAT: Port1 Match . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
SFR Definition 14.15. P1MASK: Port1 Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
SFR Definition 15.1. OSCICN: Internal Oscillator Control . . . . . . . . . . . . . . . . . . . . . 135
SFR Definition 15.2. OSCICL: Internal Oscillator Calibration . . . . . . . . . . . . . . . . . . . 136
SFR Definition 15.3. OSCIFIN: Internal Fine Oscillator Calibration . . . . . . . . . . . . . . 136
SFR Definition 15.4. OSCXCN: External Oscillator Control . . . . . . . . . . . . . . . . . . . . 140
SFR Definition 15.5. CLKSEL: Clock Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
SFR Definition 16.1. SCON0: Serial Port 0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . 148
SFR Definition 16.2. SBUF0: Serial (UART0) Port Data Buffer . . . . . . . . . . . . . . . . . 149
SFR Definition 17.1. LINADDR: Indirect Address Register . . . . . . . . . . . . . . . . . . . . . 153
SFR Definition 17.2. LINDATA: LIN Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
SFR Definition 17.3. LINCF Control Mode Register . . . . . . . . . . . . . . . . . . . . . . . . . . 153
SFR Definition 17.4. LINDT1: LIN Data Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
SFR Definition 17.5. LINDT2: LIN Data Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
SFR Definition 17.6. LINDT3: LIN Data Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
SFR Definition 17.7. LINDT4: LIN Data Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
SFR Definition 17.8. LINDT5: LIN Data Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
SFR Definition 17.9. LINDT6: LIN Data Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
SFR Definition 17.10. LINDT7: LIN Data Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
SFR Definition 17.11. LINDT8: LIN Data Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
SFR Definition 17.12. LINCTRL: LIN Control Register . . . . . . . . . . . . . . . . . . . . . . . . 157
SFR Definition 17.13. LINST: LIN STATUS Register . . . . . . . . . . . . . . . . . . . . . . . . . 158
SFR Definition 17.14. LINERR: LIN ERROR Register . . . . . . . . . . . . . . . . . . . . . . . . 159
SFR Definition 17.15. LINSIZE: LIN Message Size Register . . . . . . . . . . . . . . . . . . . 160
SFR Definition 17.16. LINDIV: LIN Divider Register . . . . . . . . . . . . . . . . . . . . . . . . . . 160
SFR Definition 17.17. LINMUL: LIN Multiplier Register . . . . . . . . . . . . . . . . . . . . . . . 161
SFR Definition 17.18. LINID: LIN ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
SFR Definition 18.1. SPI0CFG: SPI0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 177
SFR Definition 18.2. SPI0CN: SPI0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
SFR Definition 18.3. SPI0CKR: SPI0 Clock Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
SFR Definition 18.4. SPI0DAT: SPI0 Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
SFR Definition 19.1. TCON: Timer Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
SFR Definition 19.2. TMOD: Timer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
SFR Definition 19.3. CKCON: Clock Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
SFR Definition 19.4. TL0: Timer 0 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
SFR Definition 19.5. TL1: Timer 1 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
SFR Definition 19.6. TH0: Timer 0 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
SFR Definition 19.7. TH1: Timer 1 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
SFR Definition 19.8. TMR2CN: Timer 2 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
SFR Definition 19.9. TMR2RLL: Timer 2 Reload Register Low Byte . . . . . . . . . . . . . 197
SFR Definition 19.10. TMR2RLH: Timer 2 Reload Register High Byte . . . . . . . . . . . 197
SFR Definition 19.11. TMR2L: Timer 2 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
SFR Definition 19.12. TMR2H Timer 2 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
SFR Definition 20.1. PCA0CN: PCA Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
14
Rev. 0.3
C8051F52x-53x
SFR Definition 20.2. PCA0MD: PCA Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
SFR Definition 20.3. PCA0CPMn: PCA Capture/Compare Mode . . . . . . . . . . . . . . . 213
SFR Definition 20.4. PCA0L: PCA Counter/Timer Low Byte . . . . . . . . . . . . . . . . . . . 214
SFR Definition 20.5. PCA0H: PCA Counter/Timer High Byte . . . . . . . . . . . . . . . . . . . 214
SFR Definition 20.6. PCA0CPLn: PCA Capture Module Low Byte . . . . . . . . . . . . . . . 214
SFR Definition 20.7. PCA0CPHn: PCA Capture Module High Byte . . . . . . . . . . . . . . 214
C2 Register Definition 22.1. C2ADD: C2 Address . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
C2 Register Definition 22.2. DEVICEID: C2 Device ID . . . . . . . . . . . . . . . . . . . . . . . . 217
C2 Register Definition 22.3. REVID: C2 Revision ID . . . . . . . . . . . . . . . . . . . . . . . . . 218
C2 Register Definition 22.4. FPCTL: C2 Flash Programming Control . . . . . . . . . . . . 218
C2 Register Definition 22.5. FPDAT: C2 Flash Programming Data . . . . . . . . . . . . . . 218
Rev. 0.3
15
C8051F52x-53x
NOTES:
16
Rev. 0.3
C8051F52x-53x
1.
System Overview
The C8051F52x/C8051F53x family of devices are fully integrated, very low power, mixed-signal systemon-a-chip MCUs. Highlighted features are listed below. Refer to Table 1.1 for specific product feature
selection.
•
•
•
•
•
•
•
•
•
•
•
•
•
High-speed pipelined 8051-compatible microcontroller core (up to 25 MIPS)
In-system, full-speed, non-intrusive debug interface (on-chip)
True 12-bit 200 ksps ADC with analog multiplexer and up to 16 analog inputs
Precision programmable 24.5 MHz internal oscillator that is ±0.5% across voltage and temperature
Up to 7680 bytes of on-chip Flash memory
256 bytes of on-chip RAM
Enhanced UART, and SPI serial interfaces implemented in hardware
LIN 2.0 peripheral (V2.0 and V1.3 compatible, master and slave modes)
Three general-purpose 16-bit timers
Programmable Counter/Timer Array (PCA) with three capture/compare modules and Watchdog Timer
function
On-chip Power-On Reset, VDD Monitor, and Temperature Sensor
On-chip Voltage Comparator
Up to 16 Port I/O
With on-chip Power-On Reset, VDD monitor, Watchdog Timer, and clock oscillator, the C8051F52x/F53x
devices are truly standalone system-on-a-chip solutions. The Flash memory is byte writable and can be
reprogrammed in-circuit, providing non-volatile data storage, and also allowing field upgrades of the 8051
firmware. User software has complete control of all peripherals, and may individually shut down any or all
peripherals for power savings.
The on-chip Silicon Laboratories 2-Wire (C2) Development Interface allows non-intrusive (uses no on-chip
resources), full speed, in-circuit debugging using the production MCU installed in the final application. This
debug logic supports inspection and modification of memory and registers, setting breakpoints, single
stepping, run and halt commands. All analog and digital peripherals are fully functional while debugging
using C2. The two C2 interface pins can be shared with user functions, allowing in-system programming
and debugging without occupying package pins.
Each device is specified for 2.7 to 5.25 V operation (supply voltage can be up to 5.25 V using on-chip regulator) over the automotive temperature range (–40 to +125 °C). The F52x is available in the QFN10
(3 x 3 mm) package. The F53x is available in the QFN20 (4 x 4 mm) or the TSSOP20 package.
Rev. 0.3
17
C8051F52x-53x
C8051F526-IM
25 2 kB
256
0.5%
C8051F527-IM
25 2 kB
256
0.5%
C8051F530-IM
25 8 kB
256
0.5%
C8051F531-IM
25 8 kB
256
0.5%
C8051F533-IM
25 4 kB
256
0.5%
C8051F534-IM
25 4 kB
256
0.5%
C8051F536-IM
25 2 kB
256
0.5%
C8051F537-IM
25 2 kB
256
0.5%
C8051F530-IT
25 8 kB
256
0.5%
C8051F531-IT
25 8 kB
256
0.5%
C8051F533-IT
25 4 kB
256
0.5%
C8051F534-IT
25 4 kB
256
0.5%
C8051F536-IT
25 2 kB
256
0.5%
C8051F537-IT
25 2 kB
256
0.5%
18
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Rev. 0.3
6
6
6
6
16
16
16
16
16
16
16
16
16
16
16
16
3
—
3
—
3
—
3
—
3
—
3
—
3
—
3
—
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Package
0.5%
—
Analog Comparator
0.5%
256
3
Temperature Sensor
256
25 4 kB
6
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Internal Voltage Reference
25 4 kB
C8051F524-IM
6
LIN
C8051F523-IM
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
12-bit ADC ±1 LSB INL
0.5%
3
Port I/Os
256
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Programmable 3 Channels Counter Array
25 8 kB
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Timers (16-bit)
C8051F521-IM
UART
0.5%
SPI
Calibrated Internal 24.5 MHz Oscillator Tolerance
256
Flash Memory
25 8 kB
MIPS (Peak)
C8051F520-IM
Ordering Part Number
RAM
Table 1.1. Product Selection Guide
QFN-10
QFN-10
QFN-10
QFN-10
QFN-10
QFN-10
QFN-20
QFN-20
QFN-20
QFN-20
QFN-20
QFN-20
TSSOP-20
TSSOP-20
TSSOP-20
TSSOP-20
TSSOP-20
TSSOP-20
C8051F52x-53x
(GPIO)
VREGIN
LDO
(2.7–5.25 V)
8
0
5
1
(VDD)
VDD
GND
C2D
Debug HW
VDD
Monitor
XTAL1
XTAL2
WDT
External
Oscillator
Circuit
System
Clock
Precision
Oscillator
±0.5%
SFR Bus
C
o
r
e
P
0
PCA(3 ch.)
Port 0,1
Latch
LIN 2.0
Flash
D
r
v
P0.4/TX
P0.5/RX
P0.6/C2D
P0.7/XTAL1
P
1
P1.0/XTAL2
P1.1
P1.2/CNVSTR
P1.3
D
r
v
VDD
256 bytes
RAM
P0.0/VREF
P0.1
P0.2
P0.3
C
R
O
S
S
B
A
R
Timers
0,1,2
8 kB
Reset
RST/C2CK
UART0
SPI Bus
P1.4
P1.5
P1.6
P1.7
VREF
Reference Voltage
VREF
TEMP
SENSOR
5 V ADC
200 ksps
(12-Bit)
A
M
U
X
CP0
+
-
Figure 1.1. C8051F530 Block Diagram
Rev. 0.3
19
C8051F52x-53x
(GPIO)
VREGIN
LDO
(2.7–5.25 V)
8
0
5
1
(VDD)
VDD
GND
C2D
Debug HW
VDD
Monitor
XTAL1
XTAL2
WDT
External
Oscillator
Circuit
System
Clock
Precision
Oscillator
±0.5%
SFR Bus
C
o
r
e
P0.0/VREF
PCA(3 ch.)
C
R
O
S
S
B
A
R
Timers
0,1,2
Port 0
Latch
8 kB
Reset
RST/C2CK
UART0
SPI Bus
LIN 2.0
Flash
P0.1/C2D
D
r
v
P0.4/TX
VDD
256 bytes
RAM
VREF
Reference Voltage
VREF
TEMP
SENSOR
5 V ADC
200 ksps
(12-Bit)
A
M
U
X
CP0
Figure 1.2. C8051F520 Block Diagram
20
P
0
Rev. 0.3
+
-
P0.2/XTAL1
P0.3/XTAL2
P0.5/RX/
CNVSTR
C8051F52x-53x
1.1.
CIP-51™ Microcontroller
1.1.1. Fully 8051 Compatible Instruction Set
The C8051F52x/F53xdevices use Silicon Laboratories’ proprietary CIP-51 microcontroller core. The CIP51 is fully compatible with the MCS-51™ instruction set. Standard 803x/805x assemblers and compilers
can be used to develop software. The C8051F52x/F53xfamily has a superset of all the peripherals
included with a standard 8052.
1.1.2. Improved Throughput
The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system
clock cycles to execute, and usually have a maximum system clock of 12-to-24 MHz. By contrast, the CIP51 core executes 70% of its instructions in one or two system clock cycles, with no instructions taking more
than eight system clock cycles.
With the CIP-51's system clock running at 25 MHz, it has a peak throughput of 25 MIPS. The CIP-51 has a
total of 109 instructions. The table below shows the total number of instructions that require each execution
time.
Clocks to Execute
1
2
2/4
3
3/5
4
5
4/6
6
8
Number of Instructions
26
50
5
10
7
5
2
1
2
1
1.1.3. Additional Features
The C8051F52x/F53x family includes several key enhancements to the CIP-51 core and peripherals to
improve performance and ease of use in end applications.
An extended interrupt handler allows the numerous analog and digital peripherals to operate independently of the controller core and interrupt the controller only when necessary. By requiring less intervention
from the microcontroller core, an interrupt-driven system is more efficient and allows for easier implementation of multi-tasking, real-time systems.
Eight reset sources are available: power-on reset circuitry (POR), an on-chip VDD monitor, a Watchdog
Timer, a Missing Clock Detector, a voltage level detection from Comparator, a forced software reset, an
external reset pin, and an illegal Flash access protection circuit. Each reset source except for the POR,
Reset Input Pin, or Flash error may be disabled by the user in software. The WDT may be permanently
enabled in software after a power-on reset during MCU initialization.
The internal oscillator is factory calibrated to 24.5 MHz ±0.5% across the entire operating temperature and
voltage range. An external oscillator drive circuit is also included, allowing an external crystal, ceramic resonator, capacitor, RC, or CMOS clock source to generate the system clock.
1.1.4. On-Chip Debug Circuitry
The C8051F52x/F53x devices include on-chip Silicon Laboratories 2-Wire (C2) debug circuitry that provides non-intrusive, full speed, in-circuit debugging of the production part installed in the end application.
Silicon Laboratories’ debugging system supports inspection and modification of memory and registers,
breakpoints, and single stepping. No additional target RAM, program memory, timers, or communications
channels are required. All the digital and analog peripherals are functional and work correctly while debug-
Rev. 0.3
21
C8051F52x-53x
ging. All the peripherals (except for the ADC) are stalled when the MCU is halted, during single stepping,
or at a breakpoint in order to keep them synchronized.
The C8051F530-DK development kit provides all the hardware and software necessary to develop application code and perform in-circuit debugging with the C8051F52x/F53x MCUs. The kit includes software with
a developer's studio and debugger, a USB debug adapter, a target application board with the associated
MCU installed, and the required cables and wall-mount power supply. The development kit requires a computer with Windows installed. As shown in Figure 1.3, the PC is connected to the USB debug adapter. A
six-inch ribbon cable connects the USB debug adapter to the user's application board, picking up the two
C2 pins and GND.
The Silicon Laboratories IDE interface is a vastly superior developing and debugging configuration, compared to standard MCU emulators that use on-board "ICE Chips" and require the MCU in the application
board to be socketed. Silicon Laboratories’ debug paradigm increases ease of use and preserves the performance of the precision analog peripherals.
AC/DC
Adapter
PC
Target Board
TB1
D3
P1
J7
J4
J3
F530
J5
U1
TB2
D2
J2
HDR4
2
2
“B” SIDE
1
J1
P1.4_A
“A” SIDE
1
P1.4_B
C8051T530 TB
U2
HDR3
SILICON LABORATORIES
F530
JTAG
HDR1
JTAG
T2
T1
D1
RESET_A
Run
Stop
Silicon Laboratories
USB DEBUG ADAPTER
Power
USB
Cable
HDR2
RESET_B
P5
USB Debug Adapter
Prototype
Area
Figure 1.3. Development/In-System Debug Diagram
1.2.
On-Chip Memory
The CIP-51 has a standard 8051 program and data address configuration. It includes 256 bytes of data
RAM, with the upper 128 bytes dual-mapped. Indirect addressing accesses the upper 128 bytes of general
purpose RAM, and direct addressing accesses the 128 byte SFR address space. The lower 128 bytes of
RAM are accessible via direct and indirect addressing. The first 32 bytes are addressable as four banks of
general purpose registers, and the next 16 bytes can be byte addressable or bit addressable.
Program memory consists of 7680 bytes (‘F520/1 and ‘F530/1), 4 kB (‘F523/4 and ‘F533/4), or 2 kB
(‘F526/7 and ‘F536/7) of Flash. This memory is byte writable and erased in 512-byte sectors, and requires
no special off-chip programming voltage.
22
Rev. 0.3
C8051F52x-53x
PROGRAM/DATA MEMORY
(Flash)
DATA MEMORY (RAM)
INTERNAL DATA ADDRESS SPACE
‘F520/1 and ‘F530/1
0x1E00
0x1DFF
RESERVED
0xFF
0x80
0x7F
Upper 128 RAM
(Indirect Addressing
Only)
(Direct and Indirect
Addressing)
8 kB Flash
(In-System
Programmable in 512
Byte Sectors)
0x30
0x2F
0x20
0x1F
0x00
Bit Addressable
Special Function
Register's
(Direct Addressing Only)
Lower 128 RAM
(Direct and Indirect
Addressing)
General Purpose
Registers
0x0000
‘F523/4 and ‘F533/4
0x1000
RESERVED
0x0FFF
0x0000
‘F526/7 and ‘F536/7
RESERVED
0x0800
0x07FF
4 kB Flash
2 kB Flash
(In-System
Programmable in 512
Byte Sectors)
(In-System
Programmable in 512
Byte Sectors)
0x0000
Figure 1.4. Memory Map
Rev. 0.3
23
C8051F52x-53x
1.3.
Operating Modes
The C8051F52x/F53x devices have four operating modes: Active (Normal), Idle, Suspend, and Stop.
Active mode occurs during normal operation when the oscillator and peripherals are active. Idle mode halts
the CPU while leaving the peripherals and internal clocks active. In Suspend and Stop mode, the CPU is
halted, all interrupts and timers are inactive, and the internal oscillator is stopped. The various operating
modes are described in Table 1.2 below:
Table 1.2. Operating Modes Summary
Properties
Active
How
Entered?
How Exited?
•
•
•
SYSCLK active
CPU active (accessing Flash)
Peripherals active or inactive
depending on user settings
Full
—
—
•
•
SYSCLK active
CPU inactive (not accessing
Flash)
Peripherals active or inactive
depending on user settings
Less than Full
IDLE
(PCON.0)
Any enabled interrupt
or device reset
Idle
•
•
•
Internal oscillator inactive
If SYSCLK is derived from the
internal oscillator, the peripherals and the CIP-51 will be
stopped
Low
SUSPEND
(OSCICN.5)
Port 0 event match
Port 1 event match
Comparator 0 enabled
and output is logic ‘0’
•
•
SYSCLK inactive
CPU inactive (not accessing
Flash)
Digital peripherals inactive; analog peripherals active or inactive
depending on user settings
Very low
STOP
(PCON.1)
Device Reset
Suspend
Stop
Power
Consumption
•
See Section “9.3. Power Management Modes” on page 83 for Idle and Stop mode details. See Section
“15.1.1. Internal Oscillator Suspend Mode” on page 134 for more information on Suspend mode.
24
Rev. 0.3
C8051F52x-53x
1.4.
12-Bit Analog to Digital Converter
The C8051F52x/F53x devices include an on-chip 12-bit SAR ADC with a maximum throughput of
200 ksps. The ADC system includes a configurable analog multiplexer that selects the positive ADC input,
which is measured with respect to GND. Ports 0 and 1 are available as ADC inputs; additionally, the ADC
includes an innovative half gain selection which allows for inputs up to twice the Vref voltage to be sampled. The on-chip Temperature Sensor output and the core supply voltage (VDD) are also available as ADC
inputs. User firmware may shut down the ADC or use it in Burst Mode to save power.
Conversions can be initiated in three ways: a software command, an overflow of Timer 2 or an external
convert start signal. This flexibility allows the start of conversion to be triggered by software events, a periodic signal (timer overflows), or external HW signals. Conversion completions are indicated by a status bit
and an interrupt (if enabled) and occur after 1, 4, 8, or 16 samples have been accumulated by a hardware
accumulator. The resulting 12-bit to 16-bit data word is latched into the ADC data SFRs upon completion of
a conversion. When the system clock is slow, Burst Mode allows ADC0 to automatically wake from a low
power shutdown state, acquire and accumulate samples, then re-enter the low power shutdown state without CPU intervention.
Window compare registers for the ADC data can be configured to interrupt the controller when ADC data is
either within or outside of a specified range. The ADC can monitor a key voltage continuously in background mode, but not interrupt the controller unless the converted data is within/outside the specified
range.
Analog Multiplexer
Configuration, Control, and Data Registers
P0.0
Start
Conversion
P0.6*
P0.7*
P1.0*
P1.7*
Burst Mode
Logic
19-to-1
AMUX
Temp
Sensor
ADC
VDD
GND
CNVSTR Rising Edge
Timer 2 Overflow
12-Bit
SAR
* Available in
‘F53x parts
AD0BUSY (W)
End of
Conversion
Interrupt
16
ADC Data
Registers
Accumulator
Window Compare
Logic
Window
Compare
Interrupt
Figure 1.5. 12-Bit ADC Block Diagram
Rev. 0.3
25
C8051F52x-53x
1.5.
Programmable Comparator
C8051F52x/F53x devices include a software-configurable voltage comparator with an input multiplexer.
The comparator offers programmable response time and hysteresis and an output that is optionally available at the Port pins: a synchronous “latched” output (CP0). The comparator interrupt may be generated
on rising, falling, or both edges. When in IDLE or SUSPEND mode, these interrupts may be used as a
“wake-up” source for the processor. The Comparator may also be configured as a reset source. A block
diagram of the comparator is shown in Figure 1.6.
VDD
Port I/O
Pins
Multiplexer
Interrupt
Logic
+
D
-
SET
CLR
Q
Q
D
SET
CLR
Q
CP0
(synchronous output)
Q
(SYNCHRONIZER)
CP0A
(asynchronous output)
GND
Reset
Decision
Tree
Figure 1.6. Comparator Block Diagram
1.6.
Voltage Regulator
C8051F52x/F53x devices include an on-chip low dropout voltage regulator (REG0). The input to REG0 at
the VREGIN pin can be as high as 5.25 V. The output can be selected by software to 2.1 or 2.6 V. When
enabled, the output of REG0 powers the device and drives the VDD pin. The voltage regulator can be used
to power external devices connected to VDD.
1.7.
Serial Port
The C8051F52x/F53x Family includes a full-duplex UART with enhanced baud rate configuration, and an
Enhanced SPI interface. Each of the serial buses is fully implemented in hardware and makes extensive
use of the CIP-51's interrupts, thus requiring very little CPU intervention.
26
Rev. 0.3
C8051F52x-53x
1.8.
Port Input/Output
C8051F52x/F53x devices include up to 16 I/O pins. Port pins are organized as two byte-wide ports. The
port pins behave like typical 8051 ports with a few enhancements. Each port pin can be configured as a
digital or analog I/O pin. Pins selected as digital I/O can be configured for push-pull or open-drain operation. The “weak pullups” that are fixed on typical 8051 devices may be globally disabled to save power.
The Digital Crossbar allows mapping of internal digital system resources to port I/O pins. On-chip
counter/timers, serial buses, hardware interrupts, and other digital signals can be configured to appear on
the port pins using the Crossbar control registers. This allows the user to select the exact mix of generalpurpose port I/O, digital, and analog resources needed for the application.
P0MASK, P0MATCH
P1MASK, P1MATCH
Registers
XBR0, XBR1,
PnSKIP Registers
Priority
Decoder
Highest
Priority
2
UART
4
(Internal Digital Signals)
SPI
2
LIN
CP0
Outputs
Digital
Crossbar
8
7
T0, T1
(Port Latches)
P0
I/O
Cells
P1
I/O
Cells
P0.0
P0.7
P1.0*
P1.7*
2
8
P0
8
2
SYSCLK
PCA
Lowest
Priority
PnMDOUT,
PnMDIN Registers
*Available in ‘F53x
devices
(P0.0-P0.7)
8
P1
(P1.0-P1.7*)
Figure 1.7. Port I/O Functional Block Diagram
Rev. 0.3
27
C8051F52x-53x
NOTES:
28
Rev. 0.3
C8051F52x-53x
2.
Absolute Maximum Ratings
Table 2.1. Absolute Maximum Ratings
Parameter
Conditions
Min
Typ
Max
Units
Ambient temperature under bias
–40
—
125
°C
Storage Temperature
–65
—
150
°C
Voltage on VREGIN with respect to GND
–0.3
—
5.5
V
Voltage on VDD with respect to GND
–0.3
—
2.8
V
Voltage on XTAL1 with respect to GND
–0.3
—
VDD + 0.3
V
Voltage on XTAL2 with respect to GND
–0.3
—
VDD + 0.3
V
Voltage on any Port I/O Pin or RST with respect to GND
–0.3
—
VREGIN + 0.3
V
Maximum output current sunk by any Port pin
—
—
100
mA
Maximum output current sourced by any Port pin
—
—
100
mA
Maximum Total current through VREGIN, and GND
—
—
500
mA
Note: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the devices at those or any other conditions above those
indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
Rev. 0.3
29
C8051F52x-53x
3.
Global DC Electrical Characteristics
Table 3.1. Global DC Electrical Characteristics
–40 to +125 °C, 25 MHz System Clock unless otherwise specified. Typical values are given at 25 °C
Parameter
Conditions
Supply Input Voltage (VREGIN)1
Output Current = 1 mA
Core Supply Current with CPU active2
VDD = 2.1 V:
Clock = 32 kHz
Clock = 200 kHz
Clock = 1 MHz
Clock = 25 MHz
VDD = 2.6 V:
Clock = 32 kHz
Clock = 200 kHz
Clock = 1 MHz
Clock = 25 MHz
Core Supply Current with CPU inactive
(not accessing Flash)
VDD = 2.1 V:
Clock = 32 kHz
Clock = 200 kHz
Clock = 1 MHz
Clock = 25 MHz
VDD = 2.6 V:
Clock = 32 kHz
Clock = 200 kHz
Clock = 1 MHz
Clock = 25 MHz
Min.
Typ.
Max.
Units
2.7
—
5.25
V
—
—
—
13
40
0.25
9
—
—
—
—
µA
µA
mA
mA
—
—
—
21
84
0.45
9
—
—
—
—
µA
µA
mA
mA
—
—
—
—
10
22
0.15
3
—
—
—
—
µA
µA
mA
mA
—
—
—
—
15
34
0.23
4
—
—
—
—
µA
µA
mA
mA
—
Core Supply Current (suspend)2
Oscillator not running
—
0.5
—
µA
Core Supply Current (shutdown)
Oscillator not running
—
0.5
—
µA
Core Supply RAM Data Retention Voltage
—
1.5
—
V
SYSCLK (System Clock)3
0
—
25
MHz
–40
—
+125
°C
Specified Operating Temperature Range
Notes:
1. For more information on VREGIN characteristics, see Table 7.1 on page 68.
2. For more information please refer to Table 15.1 on page 142.
3. SYSCLK must be at least 32 kHz to enable debugging.
30
Rev. 0.3
C8051F52x-53x
4.
Pinout and Package Definitions
RST/C2CK
1
10
P0.1/C2D
P0.0/VREF
2
9
P0.2/XTAL1
GND
3
8
P0.3/XTAL2
VDD
4
7
P0.4/TX
VREGIN
5
6
P0.5/CNVSTR/RX
C8051F520/1/3/4/6/7
Top View
GND
Table 4.1. Pin Definitions for the C8051F520 (QFN 10)
Name
Pin
RST/
Type
Description
D I/O
Device Reset. Open-drain output of internal POR or VDD monitor. An
external source can initiate a system reset by driving this pin low for at
least 15 µs. A 1 kΩ pullup to VDD is recommended. See Reset
Sources Section for a complete description.
D I/O
Clock signal for the C2 Debug Interface.
1
C2CK
P0.0/
VREF
D I/O or Port 0.0. See Port I/O Section for a complete description.
A In
2
A O or
D In
External VREF Input. See VREF Section.
GND
3
Ground.
VDD
4
Core Supply Voltage.
VREGIN
5
On-Chip Voltage Regulator Input.
P0.5/RX*/
D I/O or Port 0.5. See Port I/O Section for a complete description.
A In
6
CNVSTR
P0.4/TX*
D In
7
External Converter start input for the ADC0, see Section “5. 12-Bit
ADC (ADC0)” on page 41 for a complete description.
D I/O or Port 0.4. See Port I/O Section for a complete description.
A In
*Note: Please refer to Section “21. Revision Specific Behavior” on page 215.
Rev. 0.3
31
C8051F52x-53x
Table 4.1. Pin Definitions for the C8051F520 (QFN 10) (Continued)
Name
Pin
P0.3
XTAL2
Type
Description
D I/O or Port 0.3. See Port I/O Section for a complete description.
A In
8
P0.2
D I/O
External Clock Output. For an external crystal or resonator, this pin is
the excitation driver. This pin is the external clock input for CMOS,
capacitor, or RC oscillator configurations. See Section “15. Oscillators”
on page 133.
D I/O or Port 0.2. See Port I/O Section for a complete description.
9
XTAL1
A In
P0.1/
External Clock Input. This pin is the external oscillator return for a crystal or resonator. Section “15. Oscillators” on page 133.
D I/O or Port 0.1. See Port I/O Section for a complete description.
A In
10
C2D
D I/O
Bi-directional data signal for the C2 Debug Interface
*Note: Please refer to Section “21. Revision Specific Behavior” on page 215.
32
Rev. 0.3
C8051F52x-53x
1
20
P0.3
P0.1
2
19
P0.4/TX
RST/C2CK
3
18
P0.5/RX
P0.0/VREF
4
17
P0.6/C2D
GND
5
16
P0.7/XTAL1
VDD
6
15
P1.0/XTAL2
VREGIN
7
14
P1.1
P1.7
8
13
P1.2/CNVSTR
P1.6
9
12
P1.3
P1.5
10
11
P1.4
C8051F530/1/3/4/6/7
P0.2
Table 4.2. Pin Definitions for the C8051F530 (TSSOP 20)
Name
P0.2
P0.1
Pin
Type
Description
1
D I/O or Port 0.2. See Port I/O Section for a complete description.
A In
2
D I/O or Port 0.1. See Port I/O Section for a complete description.
A In
RST/
D I/O
Device Reset. Open-drain output of internal POR or VDD monitor. An
external source can initiate a system reset by driving this pin low for at
least 15 µs. A 1 kΩ pullup to VDD is recommended. See Reset
Sources Section for a complete description.
D I/O
Clock signal for the C2 Debug Interface.
3
C2CK
P0.0/
D I/O or Port 0.0. See Port I/O Section for a complete description.
A In
4
VREF
A O or
D In
External VREF Input. See VREF Section.
GND
5
Ground.
VDD
6
Core Supply Voltage.
VREGIN
7
On-Chip Voltage Regulator Input.
P1.7
8
D I/O or Port 1.7. See Port I/O Section for a complete description.
A In
P1.6
9
D I/O or Port 1.6. See Port I/O Section for a complete description.
A In
*Note: Please refer to Section “21. Revision Specific Behavior” on page 215.
Rev. 0.3
33
C8051F52x-53x
Table 4.2. Pin Definitions for the C8051F530 (TSSOP 20) (Continued)
Name
Pin
Type
Description
P1.5
10
D I/O or Port 1.5. See Port I/O Section for a complete description.
A In
P1.4
11
D I/O or Port 1.4. See Port I/O Section for a complete description.
A In
P1.3
12
D I/O or Port 1.3. See Port I/O Section for a complete description.
A In
D I/O or Port 1.2. See Port I/O Section for a complete description.
A In
P1.2/
13
CNVSTR
P1.1
D In
14
P1.0/
XTAL2
External Converter start input for the ADC0, see Section “5. 12-Bit
ADC (ADC0)” on page 41 for a complete description.
D I/O or Port 1.1. See Port I/O Section for a complete description.
A In
D I/O or Port 1.0. See Port I/O Section for a complete description.
A In
15
P0.7/
D I/O
External Clock Output. For an external crystal or resonator, this pin is
the excitation driver. This pin is the external clock input for CMOS,
capacitor, or RC oscillator configurations. See Section “15. Oscillators”
on page 133.
D I/O or Port 0.7. See Port I/O Section for a complete description.
A In
16
XTAL1
A In
P0.6/
17
C2D
P0.5/RX*
P0.4/TX*
P0.3
External Clock Input. This pin is the external oscillator return for a crystal or resonator. Section “15. Oscillators” on page 133.
D I/O or Port 0.6. See Port I/O Section for a complete description.
A In
D I/O
Bi-directional data signal for the C2 Debug Interface.
18
D I/O or Port 0.5. See Port I/O Section for a complete description.
A In
19
D I/O or Port 0.4. See Port I/O Section for a complete description.
A In
20
D I/O or Port 0.3. See Port I/O Section for a complete description.
A In
*Note: Please refer to Section “21. Revision Specific Behavior” on page 215.
34
Rev. 0.3
P0.1
P0.2
P0.3
P0.4/TX
P0.5/RX
20
19
18
17
16
C8051F52x-53x
RST/C2CK
1
15
P0.6/C2D
P0.0/V REF
2
14
P0.7/XTAL1
GND
3
13
P1.0/XTAL2
V DD
4
12
P1.1
V REGIN
5
11
P1.2/CNVSTR
C8051F530/1/3/4/6/7
Top View
8
9
10
P1.4
P1.3
7
P1.6
P1.5
6
P1.7
GND
Table 4.3. Pin Definitions for the C8051F530 (QFN 20)
Name
Pin
RST/
Type
Description
D I/O
Device Reset. Open-drain output of internal POR or VDD monitor. An
external source can initiate a system reset by driving this pin low for at
least 15 µs. A 1 kΩ pullup to VDD is recommended. See Reset
Sources Section for a complete description.
D I/O
Clock signal for the C2 Debug Interface.
1
C2CK
P0.0/
D I/O or Port 0.0. See Port I/O Section for a complete description.
A In
2
VREF
A O or
D In
External VREF Input. See VREF Section.
GND
3
Ground.
VDD
4
Core Supply Voltage.
VREGIN
5
On-Chip Voltage Regulator Input.
P1.7
6
D I/O or Port 1.7. See Port I/O Section for a complete description.
A In
P1.6
7
D I/O or Port 1.6. See Port I/O Section for a complete description.
A In
P1.5
8
D I/O or Port 1.5. See Port I/O Section for a complete description.
A In
*Note: Please refer to Section “21. Revision Specific Behavior” on page 215.
Rev. 0.3
35
C8051F52x-53x
Table 4.3. Pin Definitions for the C8051F530 (QFN 20) (Continued)
Name
Pin
P1.4
9
D I/O or Port 1.4. See Port I/O Section for a complete description.
A In
P1.3
10
D I/O or Port 1.3. See Port I/O Section for a complete description.
A In
P1.1
11
12
P1.0/
XTAL2
D In
13
D I/O or Port 1.1. See Port I/O Section for a complete description.
A In
D I/O
14
A In
P0.6/
15
C2D
P0.3
P0.2
P0.1
External Clock Output. For an external crystal or resonator, this pin is
the excitation driver. This pin is the external clock input for CMOS,
capacitor, or RC oscillator configurations. Section “15. Oscillators” on
page 133.
D I/O or Port 0.7. See Port I/O Section for a complete description.
XTAL1
P0.4/TX*
External Converter start input for the ADC0, see Section “5. 12-Bit
ADC (ADC0)” on page 41 for a complete description.
D I/O or Port 1.0. See Port I/O Section for a complete description.
A In
P0.7/
P0.5/RX*
Description
D I/O or Port 1.2. See Port I/O Section for a complete description.
A In
P1.2/
CNVSTR
Type
External Clock Input. This pin is the external oscillator return for a crystal or resonator. See Oscillator Section.
D I/O or Port 0.6. See Port I/O Section for a complete description.
A In
D I/O
Bi-directional data signal for the C2 Debug Interface.
16
D I/O or Port 0.5. See Port I/O Section for a complete description.
A In
17
D I/O or Port 0.4. See Port I/O Section for a complete description.
A In
18
D I/O or Port 0.3. See Port I/O Section for a complete description.
A In
19
D I/O or Port 0.2. See Port I/O Section for a complete description.
A In
20
D I/O or Port 0.1. See Port I/O Section for a complete description.
A In
*Note: Please refer to Section “21. Revision Specific Behavior” on page 215.
36
Rev. 0.3
C8051F52x-53x
θ1
Figure 4.1. TSSOP-20 Package Diagram
Table 4.4. TSSOP-20 Package Diagram Dimensions
Symbol
Min
A
A1
A2
D
E
E1
L
c
e
θ1
bbb
ddd
—
0.05
0.80
6.40
4.30
0.45
0.09
0°
Nom
—
—
1.00
6.50
6.40 BSC
4.40
0.60
—
0.65 BSC
—
0.10
0.20
Max
1.20
0.15
1.05
6.60
4.50
0.75
0.20
8°
Notes:
1. All dimensions shown are in millimeters (mm).
2. Dimensioning and Tolerancing per ANSI Y14.5M-1982.
3. This drawing conforms to JEDEC outline MO-153, variation AC.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020C
specification for Small Body Components.
Rev. 0.3
37
C8051F52x-53x
Figure 4.2. QFN-20 Package Diagram
Table 4.5. QFN-20 Package Diagram Dimensions
Dimension
Min
Nom
Max
A
A1
A3
b
D
D2
e
E
E2
L
aaa
bbb
ddd
eee
0.80
0.03
0.90
0.07
0.25 REF
0.25
4.00 BSC.
2.70
0.50 BSC.
4.00 BSC.
2.70
0.40
-----
1.00
0.11
0.18
2.55
2.55
0.30
-----
0.30
2.85
2.85
0.50
0.15
0.10
0.05
0.08
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to JEDEC outline MO-43, variation VGGD except for
custom features D2, E2, and L which are toleranced per supplier designation.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020C
specification for Small Body Components.
38
Rev. 0.3
C8051F52x-53x
Figure 4.3. QFN-10 Package Diagram
Table 4.6. QFN-10 Package Diagram Dimensions
Dimension
Min
Nom
Max
A
A1
A3
b
D
D2
e
E
E2
L
aaa
bbb
ddd
eee
0.80
0.03
0.90
0.07
0.25 REF
0.25
3.00 BSC.
1.646
0.50 BSC.
3.00 BSC.
2.384
0.40
—
—
—
—
1.00
0.11
0.18
1.496
2.234
0.30
—
—
—
—
0.30
1.796
2.534
0.50
0.15
0.15
0.05
0.08
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to JEDEC outline MO-243, variation VEED except for
custom features D2, E2, and L which are toleranced per supplier designation.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020C
specification for Small Body Components.
Rev. 0.3
39
C8051F52x-53x
NOTES:
40
Rev. 0.3
C8051F52x-53x
5.
12-Bit ADC (ADC0)
The ADC0 subsystem for the C8051F52x/F53x Family consists of an analog multiplexer (AMUX0) with
16/6 total input selections, and a 200 ksps, 12-bit successive-approximation-register ADC with integrated
track-and-hold, programmable window detector, programmable attenuation (1:2), and hardware accumulator. The ADC0 subsystem has a special Burst Mode which can automatically enable ADC0, capture and
accumulate samples, then place ADC0 in a low power shutdown mode without CPU intervention. The
AMUX0, data conversion modes, and window detector are all configurable under software control via the
Special Function Registers shown in Figure 5.1. ADC0 inputs are single-ended and may be configured to
measure P0.0-P2.7, the Temperature Sensor output, VDD, or GND with respect to GND. ADC0 is enabled
when the AD0EN bit in the ADC0 Control register (ADC0CN) is set to logic 1, or when performing conversions in Burst Mode. ADC0 is in low power shutdown when AD0EN is logic 0 and no Burst Mode conversions are taking place.
P1.7*
19-to-1
AMUX0
ADC
AD0TM1:0
*Available in ‘F53x
devices
VDD
AD0RPT1
AD0RPT0
AD0SC4
GND
AD0SC3
AD0SC2
AD0SC1
AD0SC0
Temp Sensor
ADC0CF
10
CNVSTR Input
11
Timer 2 Overflow
ADC0L
12-Bit
SAR
AD0BUSY (W)
Timer 1 Overflow
Accumulator
ADC0H
Burst Mode
Oscillator
25 MHz Max
00
01
AD0PRE
AD0POST
FCLK
REF
P0.7
P1.0*
Start
Conversion
Burst Mode
Logic
FCLK
SYSCLK
VDD
AD0CM1
AD0CM0
AD0EN
BURSTEN
AD0TM1
AD0TM0
AD0TK1
AD0TK0
AD0PWR2
AD0PWR1
AD0PWR0
AD0PWR3
Start
Conversion
P0.0
AD0INT
AD0BUSY
AD0WINT
AD0LJST
ADC0CN
ADC0TK
ADC0MX1
ADC0MX0
ADC0MX4
ADC0MX3
ADC0MX2
ADC0MX
ADC0LTH ADC0LTL
AD0WINT
32
Window
Compare
Logic
ADC0GTH ADC0GTL
Figure 5.1. ADC0 Functional Block Diagram
5.1.
Analog Multiplexer
AMUX0 selects the input channel to the ADC. Any of the following may be selected as an input: P0.0–
P1.7, the on-chip temperature sensor, the core power supply (VDD), or ground (GND). ADC0 is singleended and all signals measured are with respect to GND. The ADC0 input channels are selected using
the ADC0MX register as described in SFR Definition 5.1.
Important Note About ADC0 Input Configuration: Port pins selected as ADC0 inputs should be configured as analog inputs, and should be skipped by the Digital Crossbar. To configure a Port pin for analog
input, set to ‘0’ the corresponding bit in register PnMDIN (for n = 0,1). To force the Crossbar to skip a Port
pin, set to ‘1’ the corresponding bit in register PnSKIP (for n = 0,1). See Section “14. Port Input/Output” on
page 117 for more Port I/O configuration details.
Rev. 0.3
41
C8051F52x-53x
5.2.
Temperature Sensor
The typical temperature sensor transfer function is shown in Figure 5.2. The output voltage (VTEMP) is the
positive ADC input when the temperature sensor is selected by bits AD0MX4–0 in register ADC0MX.
(Volts)
1.000
0.900
0.800
VTEMP = TBD (TEMPC) + TBD mV
0.700
0.600
0.500
-50
0
50
100
(Celsius)
Figure 5.2. Typical Temperature Sensor Transfer Function
5.3.
ADC0 Operation
In a typical system, ADC0 is configured using the following steps:
Step 1. If an attenuation (1:2) is required please refer to Section “5.5. Selectable Attenuation” on
page 57.
Step 2. Choose the start of conversion source.
Step 3. Choose Normal Mode or Burst Mode operation.
Step 4. If Burst Mode, choose the ADC0 Idle Power State and set the Power-Up Time.
Step 5. Choose the tracking mode. Note that Pre-Tracking Mode can only be used with Normal
Mode.
Step 6. Calculate required settling time and set the post convert-start tracking time using the
AD0TK bits.
Step 7. Choose the repeat count.
Step 8. Choose the output word justification (Right-Justified or Left-Justified).
Step 9. Enable or disable the End of Conversion and Window Comparator Interrupts.
42
Rev. 0.3
C8051F52x-53x
5.3.1. Starting a Conversion
A conversion can be initiated in one of four ways, depending on the programmed states of the ADC0 Start
of Conversion Mode bits (AD0CM1–0) in register ADC0CN. Conversions may be initiated by one of the following:
•Writing a ‘1’ to the AD0BUSY bit of register ADC0CN
•A rising edge on the CNVSTR input signal (pin P0.6)
•A Timer 1 overflow (i.e., timed continuous conversions)
•A Timer 2 overflow (i.e., timed continuous conversions)
Writing a ‘1’ to AD0BUSY provides software control of ADC0 whereby conversions are performed "ondemand.” During conversion, the AD0BUSY bit is set to logic 1 and reset to logic 0 when the conversion is
complete. The falling edge of AD0BUSY triggers an interrupt (when enabled) and sets the ADC0 interrupt
flag (AD0INT). Note: When polling for ADC conversion completions, the ADC0 interrupt flag (AD0INT)
should be used. Converted data is available in the ADC0 data registers, ADC0H:ADC0L, when bit AD0INT
is logic 1. Note that when Timer 2 overflows are used as the conversion source, Low Byte overflows are
used if Timer2 is in 8-bit mode; High byte overflows are used if Timer 2 is in 16-bit mode. See Section
“19. Timers” on page 185 for timer configuration.
5.3.2. Tracking Modes
According to Table 5.1 and Table 5.2, each ADC0 conversion must be preceded by a minimum tracking
time for the converted result to be accurate. ADC0 has three tracking modes: Pre-Tracking, Post-Tracking,
and Dual-Tracking. Pre-Tracking Mode provides the minimum delay between the convert start signal and
end of conversion by tracking continuously before the convert start signal. This mode requires software
management in order to meet minimum tracking requirements. In Post-Tracking Mode, a programmable
tracking time starts after the convert start signal and is managed by hardware. Dual-Tracking Mode maximizes tracking time by tracking before and after the convert start signal. Figure 5.3 shows examples of the
three tracking modes.
Pre-Tracking Mode is selected when AD0TM is set to 10b. Conversions are started immediately following
the convert start signal. ADC0 is tracking continuously when not performing a conversion. Software must
allow at least the minimum tracking time between each end of conversion and the next convert start signal.
The minimum tracking time must also be met prior to the first convert start signal after ADC0 is enabled.
Post-Tracking Mode is selected when AD0TM is set to 01b. A programmable tracking time based on
AD0TK is started immediately following the convert start signal. Conversions are started after the programmed tracking time ends. After a conversion is complete, ADC0 does not track the input. Rather, the
sampling capacitor remains disconnected from the input making the input pin high-impedance until the
next convert start signal.
Dual-Tracking Mode is selected when AD0TM is set to 11b. A programmable tracking time based on
AD0TK is started immediately following the convert start signal. Conversions are started after the programmed tracking time ends. After a conversion is complete, ADC0 tracks continuously until the next conversion is started.
Depending on the output connected to the ADC input, additional tracking time, more than is specified in
Table 5.1 and Table 5.2, may be required after changing MUX settings. See the settling time requirements
described in Section “5.3.6. Settling Time Requirements” on page 48.
Rev. 0.3
43
C8051F52x-53x
Convert Start
Pre-Tracking
AD0TM = 10
Track
Post-Tracking
AD0TM= 01
Idle
Track
Convert
Idle
Track
Convert..
Dual-Tracking
AD0TM = 11
Track
Track
Convert
Track
Track
Convert..
Convert
Track
Convert ...
Figure 5.3. ADC0 Tracking Modes
5.3.3. Timing
ADC0 has a maximum conversion speed specified in Table 5.1 and Table 5.2. ADC0 is clocked from the
ADC0 Subsystem Clock (FCLK). The source of FCLK is selected based on the BURSTEN bit. When
BURSTEN is logic 0, FCLK is derived from the current system clock. When BURSTEN is logic 1, FCLK is
derived from the Burst Mode Oscillator, an independent clock source with a maximum frequency of
25 MHz.
When ADC0 is performing a conversion, it requires a clock source that is typically slower than FCLK. The
ADC0 SAR conversion clock (SAR clock) is a divided version of FCLK. The divide ratio can be configured
using the AD0SC bits in the ADC0CF register. The maximum SAR clock frequency is listed in Table 5.1
and Table 5.2.
ADC0 can be in one of three states at any given time: tracking, converting, or idle. Tracking time depends
on the tracking mode selected. For Pre-Tracking Mode, tracking is managed by software and ADC0 starts
conversions immediately following the convert start signal. For Post-Tracking and Dual-Tracking Modes,
the tracking time after the convert start signal is equal to the value determined by the AD0TK bits plus 2
FCLK cycles. Tracking is immediately followed by a conversion. The ADC0 conversion time is always 13
SAR clock cycles plus an additional 2 FCLK cycles to start and complete a conversion. Figure 5.4 shows
timing diagrams for a conversion in Pre-Tracking Mode and tracking plus conversion in Post-Tracking or
Dual-Tracking Mode. In this example, repeat count is set to one.
44
Rev. 0.3
C8051F52x-53x
Convert Start
Pre-Tracking Mode
Time
F
S1
S2
ADC0 State
...
S12
S13
F
Convert
AD0INT Flag
Post-Tracking or Dual-Tracking Modes (AD0TK = ‘00')
Time
F
S1
ADC0 State
S2
F F
S1
Track
...
S2
S12
S13
F
Convert
AD0INT Flag
Key
F
Sn
Equal to one period of FCLK.
Each Sn is equal to one period of the SAR clock.
Figure 5.4. 12-Bit ADC Tracking Mode Example
Rev. 0.3
45
C8051F52x-53x
5.3.4. Burst Mode
Burst Mode is a power saving feature that allows ADC0 to remain in a very low power state between conversions. When Burst Mode is enabled, ADC0 wakes from a very low power state, accumulates 1, 4, 8, or
16 samples using an internal Burst Mode clock (approximately 25 MHz), then re-enters a very low power
state. Since the Burst Mode clock is independent of the system clock, ADC0 can perform multiple conversions then enter a very low power state within a single system clock cycle, even if the system clock is slow
(e.g. 32.768 kHz), or suspended.
Burst Mode is enabled by setting BURSTEN to logic 1. When in Burst Mode, AD0EN controls the ADC0
idle power state (i.e. the state ADC0 enters when not tracking or performing conversions). If AD0EN is set
to logic 0, ADC0 is powered down after each burst. If AD0EN is set to logic 1, ADC0 remains enabled after
each burst. On each convert start signal, ADC0 is awakened from its Idle Power State. If ADC0 is powered
down, it will automatically power up and wait the programmable Power-Up Time controlled by the
AD0PWR bits. Otherwise, ADC0 will start tracking and converting immediately. Figure 5.5 shows an example of Burst Mode Operation with a slow system clock and a repeat count of 4.
Important Note: When Burst Mode is enabled, only Post-Tracking and Dual-Tracking modes can be used.
When Burst Mode is enabled, a single convert start will initiate a number of conversions equal to the repeat
count. When Burst Mode is disabled, a convert start is required to initiate each conversion. In both modes,
the ADC0 End of Conversion Interrupt Flag (AD0INT) will be set after “repeat count” conversions have
been accumulated. Similarly, the Window Comparator will not compare the result to the greater-than and
less-than registers until “repeat count” conversions have been accumulated.
Note: When using Burst Mode, care must be taken to issue a convert start signal no faster than once every
four SYSCLK periods. This includes external convert start signals.
S y s te m C lo c k
C o n v e rt S ta rt
P o s t-T ra c k in g
A D 0TM = 01
AD0EN = 0
P o w e re d
D ow n
P o w e r-U p
a n d Id le
T
C
T
C
T
C
T
C
P o w e re d
D ow n
P o w e r-U p
a n d Id le
T
C ..
D u a l-T ra c k in g
A D 0TM = 11
AD0EN = 0
P o w e re d
D ow n
P o w e r-U p
a n d T ra c k
T
C
T
C
T
C
T
C
P o w e re d
D ow n
P o w e r-U p
a n d T ra c k
T
C ..
AD0PW R
P o s t-T ra c k in g
A D 0TM = 01
AD0EN = 1
Id le
T
C
T
C
T
C
T
C
Id le
T
C
T
C
T
C ..
D u a l-T ra c k in g
A D 0TM = 11
AD0EN = 1
T ra c k
T
C
T
C
T
C
T
C
T ra c k
T
C
T
C
T
C ..
T = T ra c k in g
C = C o n v e rtin g
Figure 5.5. 12-Bit ADC Burst Mode Example with Repeat Count Set to 4
46
Rev. 0.3
C8051F52x-53x
5.3.5. Output Conversion Code
The registers ADC0H and ADC0L contain the high and low bytes of the output conversion code. When the
repeat count is set to 1, conversion codes are represented in 12-bit unsigned integer format and the output
conversion code is updated after each conversion. Inputs are measured from ‘0’ to VREF x 4095/4096.
Data can be right-justified or left-justified, depending on the setting of the AD0LJST bit (ADC0CN.2).
Unused bits in the ADC0H and ADC0L registers are set to ‘0’. Example codes are shown below for both
right-justified and left-justified data.
Input Voltage
VREF x 4095/4096
VREF x 2048/4096
VREF x 2047/4096
0
Right-Justified ADC0H:ADC0L
(AD0LJST = 0)
0x0FFF
0x0800
0x07FF
0x0000
Left-Justified ADC0H:ADC0L
(AD0LJST = 1)
0xFFF0
0x8000
0x7FF0
0x0000
When the ADC0 Repeat Count is greater than 1, the output conversion code represents the accumulated
result of the conversions performed and is updated after the last conversion in the series is finished. The
output value can be 14-bit (4 samples), 15-bit (8 samples), or 16-bit (16 samples) in unsigned integer
format based on the selected repeat count. The repeat count can be selected using the AD0RPT bits in the
ADC0CF register. The value must be right-justified (AD0LJST = “0”), and unused bits in the ADC0H and
ADC0L registers are set to '0'. The following example shows right-justified codes for repeat counts greater
than 1. Notice that accumulating 2n samples is equivalent to left-shifting by n bit positions when all samples
returned from the ADC have the same value.
Input Voltage
VREF x 4095/4096
VREF x 2048/4096
VREF x 2047/4096
0
Repeat Count = 4
0x3FFC
0x2000
0x1FFC
0x0000
Repeat Count = 8
0x7FF8
0x4000
0x3FF8
0x0000
Rev. 0.3
Repeat Count = 16
0xFFF0
0x8000
0x7FF0
0x0000
47
C8051F52x-53x
5.3.6. Settling Time Requirements
A minimum tracking time is required before an accurate conversion can be performed. This tracking time is
determined by the AMUX0 resistance, the ADC0 sampling capacitance, any external source resistance,
and the accuracy required for the conversion.
Figure 5.6 shows the equivalent ADC0 input circuit. The required ADC0 settling time for a given settling
accuracy (SA) may be approximated by Equation 5.1. When measuring the Temperature Sensor output or
VDD with respect to GND, RTOTAL reduces to RMUX. See Table 5.1 and Table 5.2 for ADC0 minimum settling time requirements.
n
2
t = ln ⎛ -------⎞ × R TOTAL C SAMPLE
⎝ SA⎠
Equation 5.1. ADC0 Settling Time Requirements
Where:
SA is the settling accuracy, given as a fraction of an LSB (for example, 0.25 to settle within 1/4 LSB)
t is the required settling time in seconds
RTOTAL is the sum of the AMUX0 resistance and any external source resistance.
n is the ADC resolution in bits (12).
MUX Select
Px.x
RMUX = TBD
CSAMPLE = TBD
RC Input= RMUX * CSAMPLE
Figure 5.6. ADC0 Equivalent Input Circuits
48
Rev. 0.3
C8051F52x-53x
SFR Definition 5.1. ADC0MX: ADC0 Channel Select
R
R
R
-
-
-
Bit7
Bit6
Bit5
R/W
R/W
Bit4
Bit3
R/W
R/W
R/W
Reset Value
Bit1
Bit0
SFR Address:
AD0MX
Bit2
00011111
0xBB
Bits7–5: UNUSED. Read = 000b; Write = don’t care.
Bits4–0: AD0MX4–0: AMUX0 Positive Input Selection
AD0MX4–0
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
11000
11001
11010 - 11111
ADC0 Input Channel
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6*
P0.7*
P1.0*
P1.1*
P1.2*
P1.3*
P1.4*
P1.5*
P1.6*
P1.7*
Temp Sensor
VDD
GND
*Note: Only applies to C8051F53x parts.
Rev. 0.3
49
C8051F52x-53x
SFR Definition 5.2. ADC0CF: ADC0 Configuration
R/W
R/W
Bit7
Bit6
R/W
R/W
R/W
R/W
Bit4
Bit3
Bit2
AD0SC
Bit5
R/W
AD0RPT
Bit1
R/W
Reset Value
ATTEN
11111000
Bit0
SFR Address:
0xBC
Bits7–3: AD0SC4–0: ADC0 SAR Conversion Clock Period Bits.
SAR Conversion clock is derived from FCLK by the following equation, where AD0SC refers
to the 5-bit value held in bits AD0SC4–0. SAR Conversion clock requirements are given in
Table 5.1.
BURSTEN = 0: FCLK is the current system clock.
BURSTEN = 1: FCLK is a maximum of 25 MHz, independent of the current system clock.
FCLK
AD0SC = -------------------- – 1 *
CLK SAR
or
FCLK
CLK SAR = ---------------------------AD0SC + 1
*Note: Round the result up.
Bits2–1: AD0RPT1–0: ADC0 Repeat Count.
Controls the number of conversions taken and accumulated between ADC0 End of
Conversion (ADCINT) and ADC0 Window Comparator (ADCWINT) interrupts. A convert
start is required for each conversion unless Burst Mode is enabled. In Burst Mode, a single
convert start can initiate multiple self-timed conversions. Results in both modes are
accumulated in the ADC0H:ADC0L register. When AD0RPT1–0 are set to a value other
than '00', the AD0LJST bit in the ADC0CN register must be set to '0' (right justified).
00: 1 conversion is performed.
01: 4 conversions are performed and accumulated.
10: 8 conversions are performed and accumulated.
11: 16 conversions are performed and accumulated.
Bit0:
50
ATTEN: Attenuation Enabled Bit.
Controls the attenuation programming. For more information of the usage please refer to
the following chapter: Section “5.5. Selectable Attenuation” on page 57.
Rev. 0.3
C8051F52x-53x
SFR Definition 5.3. ADC0H: ADC0 Data Word MSB
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
00000000
0xBE
Bits7–0: ADC0 Data Word High-Order Bits.
For AD0LJST = 0 and AD0RPT as follows:
00: Bits 3–0 are the upper 4 bits of the 12-bit result. Bits 7–4 are 0000b.
01: Bits 4–0 are the upper 5 bits of the 14-bit result. Bits 7–5 are 000b.
10: Bits 5–0 are the upper 6 bits of the 15-bit result. Bits 7–6 are 00b.
11: Bits 7–0 are the upper 8 bits of the 16-bit result.
For AD0LJST = 1 (AD0RPT must be '00'): Bits 7–0 are the most-significant bits of the ADC0
12-bit result.
SFR Definition 5.4. ADC0L: ADC0 Data Word LSB
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
0xBD
Bits7–0: ADC0 Data Word Low-Order Bits.
For AD0LJST = 0: Bits 7–0 are the lower 8 bits of the ADC0 Accumulated Result.
For AD0LJST = 1 (AD0RPT must be '00'): Bits 7–4 are the lower 4 bits of the 12-bit result.
Bits 3–0 are 0000b.
Rev. 0.3
51
C8051F52x-53x
SFR Definition 5.5. ADC0CN: ADC0 Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
AD0EN BURSTEN AD0INT AD0BUSY AD0WINT AD0LJST AD0CM1
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
(bit addressable)
Bit7:
Reset Value
AD0CM0 00000000
SFR Address:
0xE8
AD0EN: ADC0 Enable Bit.
0: ADC0 Disabled. ADC0 is in low-power shutdown.
1: ADC0 Enabled. ADC0 is active and ready for data conversions.
Bit6:
BURSTEN: ADC0 Burst Mode Enable Bit.
0: ADC0 Burst Mode Disabled.
1: ADC0 Burst Mode Enabled.
Bit5:
AD0INT: ADC0 Conversion Complete Interrupt Flag.
0: ADC0 has not completed a data conversion since the last time AD0INT was cleared.
1: ADC0 has completed a data conversion.
Bit4:
AD0BUSY: ADC0 Busy Bit.
Read:
0: ADC0 conversion is complete or a conversion is not currently in progress. AD0INT is set
to logic 1 on the falling edge of AD0BUSY.
1: ADC0 conversion is in progress.
Write:
0: No Effect.
1: Initiates ADC0 Conversion if AD0CM1–0 = 00b
Bit3:
AD0WINT: ADC0 Window Compare Interrupt Flag.
This bit must be cleared by software.
0: ADC0 Window Comparison Data match has not occurred since this flag was last cleared.
1: ADC0 Window Comparison Data match has occurred.
Bit2:
AD0LJST: ADC0 Left Justify Select
0: Data in ADC0H:ADC0L registers is right justified.
1: Data in ADC0H:ADC0L registers is left justified. This option should not be used with a
repeat count greater than 1 (when AD0RPT1–0 is 01b, 10b, or 11b).
Bits1–0: AD0CM1–0: ADC0 Start of Conversion Mode Select.
00: ADC0 conversion initiated on every write of ‘1’ to AD0BUSY.
01: ADC0 conversion initiated on overflow of Timer 1.
10: ADC0 conversion initiated on rising edge of external CNVSTR.
11: ADC0 conversion initiated on overflow of Timer 2.
52
Rev. 0.3
C8051F52x-53x
SFR Definition 5.6. ADC0TK: ADC0 Tracking Mode Select
R/W
R/W
Bit7
Bit6
R/W
R/W
R/W
Bit4
Bit3
AD0PWR
Bit5
R/W
R/W
Bit2
Bit1
AD0TM
R/W
Reset Value
Bit0
SFR Address:
AD0TK
11111111
(bit addressable)
0xBA
Bits7–4: AD0PWR3–0: ADC0 Burst Power-Up Time.
For BURSTEN = 0:
ADC0 power state controlled by AD0EN.
For BURSTEN = 1 and AD0EN = 1;
ADC0 remains enabled and does not enter the very low power state.
For BURSTEN = 1 and AD0EN = 0:
ADC0 enters the very low power state as specified in Table 5.1 and Table 5.2 and is enabled
after each convert start signal. The Power Up time is programmed according to the following
equation:
Tstartup
AD0PWR = ---------------------- – 1
200ns
or
Tstartup = ( AD0PWR + 1 )200ns
Bits3–2: AD0TM1–0: ADC0 Tracking Mode Select Bits.
00: Reserved.
01: ADC0 is configured to Post-Tracking Mode.
10: ADC0 is configured to Pre-Tracking Mode.
11: ADC0 is configured to Dual-Tracking Mode (default).
Bits1–0: AD0TK1–0: ADC0 Post-Track Time.
Post-Tracking time is controlled by AD0TK as follows:
00: Post-Tracking time is equal to 2 SAR clock cycles + 2 FCLK cycles.
01: Post-Tracking time is equal to 4 SAR clock cycles + 2 FCLK cycles.
10: Post-Tracking time is equal to 8 SAR clock cycles + 2 FCLK cycles.
11: Post-Tracking time is equal to 16 SAR clock cycles + 2 FCLK cycles.
5.4.
Programmable Window Detector
The ADC Programmable Window Detector continuously compares the ADC0 output registers to user-programmed limits, and notifies the system when a desired condition is detected. This is especially effective in
an interrupt-driven system, saving code space and CPU bandwidth while delivering faster system
response times. The window detector interrupt flag (AD0WINT in register ADC0CN) can also be used in
polled mode. The ADC0 Greater-Than (ADC0GTH, ADC0GTL) and Less-Than (ADC0LTH, ADC0LTL) registers hold the comparison values. The window detector flag can be programmed to indicate when measured data is inside or outside of the user-programmed limits, depending on the contents of the ADC0
Less-Than and ADC0 Greater-Than registers.
Rev. 0.3
53
C8051F52x-53x
SFR Definition 5.7. ADC0GTH: ADC0 Greater-Than Data High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
11111111
0xC4
Bits7–0: High byte of ADC0 Greater-Than Data Word.
SFR Definition 5.8. ADC0GTL: ADC0 Greater-Than Data Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
11111111
0xC3
Bits7–0: Low byte of ADC0 Greater-Than Data Word.
54
Rev. 0.3
C8051F52x-53x
SFR Definition 5.9. ADC0LTH: ADC0 Less-Than Data High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
0xC6
Bits7–0: High byte of ADC0 Less-Than Data Word.
SFR Definition 5.10. ADC0LTL: ADC0 Less-Than Data Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
00000000
0xC5
Bits7–0: Low byte of ADC0 Less-Than Data Word.
Rev. 0.3
55
C8051F52x-53x
5.4.1. Window Detector In Single-Ended Mode
Figure 5.7
shows
two
example
window
comparisons
for
right-justified
data
with
ADC0LTH:ADC0LTL = 0x0200 (512d) and ADC0GTH:ADC0GTL = 0x0100 (256d). The input voltage can
range from ‘0’ to VREF x (4095/4096) with respect to GND, and is represented by a 12-bit unsigned integer
value. The repeat count is set to one. In the left example, an AD0WINT interrupt will be generated if the
ADC0 conversion word (ADC0H:ADC0L) is within the range defined by ADC0GTH:ADC0GTL and
ADC0LTH:ADC0LTL (if 0x0100 < ADC0H:ADC0L < 0x0200). In the right example, and AD0WINT interrupt
will be generated if the ADC0 conversion word is outside of the range defined by the ADC0GT and
ADC0LT registers (if ADC0H:ADC0L < 0x0100 or ADC0H:ADC0L > 0x0200). Figure 5.8 shows an example using left-justified data with the same comparison values.
ADC0H:ADC0L
ADC0H:ADC0L
Input Voltage
(Px.x - GND)
VREF x (4095/4096)
Input Voltage
(Px.x - GND)
0x0FFF
VREF x (4095/
4096)
0x0FFF
AD0WINT
not affected
AD0WINT=1
0x0201
VREF x (512/4096)
0x0200
0x01FF
0x0201
ADC0LTH:ADC0LTL
VREF x (512/4096)
0x0200
0x01FF
AD0WINT=1
0x0101
VREF x (256/4096)
0x0100
0x0101
ADC0GTH:ADC0GTL
VREF x (256/4096)
0x00FF
0x0100
AD0WINT
not affected
ADC0LTH:ADC0LTL
0x00FF
AD0WINT=1
AD0WINT
not affected
0
ADC0GTH:ADC0GTL
0x0000
0x0000
0
Figure 5.7. ADC Window Compare Example: Right-Justified Single-Ended Data
ADC0H:ADC0L
ADC0H:ADC0L
Input Voltage
(Px.x - GND)
VREF x (4095/4096)
Input Voltage
(Px.x - GND)
0xFFF0
VREF x (4095/4096)
0xFFF0
AD0WINT
not affected
AD0WINT=1
0x2010
VREF x (512/4096)
0x2000
0x2010
ADC0LTH:ADC0LTL
VREF x (512/4096)
0x1FF0
0x2000
0x1FF0
AD0WINT=1
0x1010
VREF x (256/4096)
0x1000
0x1010
ADC0GTH:ADC0GTL
VREF x (256/4096)
0x0FF0
0x1000
AD0WINT
not affected
ADC0LTH:ADC0LTL
0x0FF0
AD0WINT=1
AD0WINT
not affected
0
ADC0GTH:ADC0GTL
0x0000
0
0x0000
Figure 5.8. ADC Window Compare Example: Left-Justified Single-Ended Data
56
Rev. 0.3
C8051F52x-53x
5.5.
Selectable Attenuation
The C8051F52x/F53x family of devices implements an ADC that provides a new and innovative selectable
attenuation option. This option allows the designer to take the ADC Input and either keep its input value
unchanged or attenuate by a factor of 2 (value divided by two).
The attenuation selection is performed using the following steps:
Step 1. Set the ATTEN bit (ADC0CF.0)
Step 2. Load the ADC0H with 0x04
Step 3. Load ADC0L with 0xFC if no attenuation (1/1 gain) is required or 0x7C to attenuate the
signal (1/2 gain)
Step 4. Reset the ATTEN bit (ADC0CF.0)
Notes:
1. During the Attenuation selection no ADC conversion should be performed as the results will be incorrect.
2. The maximum input voltage value is still limited to Vregin and the maximum value of the signal after attenuation
is limited to Vref otherwise the ADC will saturate.
5.6.
Typical ADC Parameters and Description
5.6.1. Resolution
The resolution of an ADC is defined as 2n, where 'n' is the number of bits of the ADC. It shows the number
of different states or codes the ADC digital output can assume (or resolve) from the analog input. For
example, a 12-bit ADC presents 212 or 4096 values.
In principle the higher the number of symbols the better is the resolution of the ADC.
5.6.2. Integral Non-Linearity (INL)
The Integral Non-Linearity (INL) of an ADC informs how much the transfer function of the ADC deviates
from the ideal linear (straight line) function. The value is obtained by measuring the maximum deviation of
the output compared with the straight line. (in LSBs or least significant bits). A typical value would be
±1LSB.
Measurement
To obtain these values the following steps are performed:
1. A number of samples of different production lots that is large enough to ensure statistical significance are selected.
2. The samples are tested by injecting a precise analog signal sweeping the best straight line
through the entire ADC range. (The best straight line is calculated so that to minimize the deviations using a least square curve fitting)
3. The maximum deviation from the transition point (offset errors and gain errors eliminated) is
calculated for each sample.
5.6.3. Differential Non-Linearity (DNL)
The Differential Non-Linearity shows the maximum distance between one symbol and the next one in
LSBs. A DNL of less than ±1 LSB guarantees that there are no missing codes. This means that if the input
voltage is swept its entire range then all code combinations will appear in the output of the converter. Many
ADCs define the DNL as ±1LSB but still guarantee that there are no missing codes. This happens because
the production test limits are tighter than the data sheet limits. If the DNL is greater than ±1LSB then the
device has missing codes.
Rev. 0.3
57
C8051F52x-53x
Measurement
To obtain these values the following steps are performed:
1. A number of samples of different production lots that is large enough to ensure statistical significance are selected.
2. The samples are tested by injecting a precise analog signal sweeping through the entire ADC
range.
3. The ADC transition point values are compared with the ideal transition point values and the
distance (DNL) from symbol to symbol is calculated.
4. The maximum difference between the actual step and the ideal one (in LSBs) represents the
DNL value for the sample.
5.6.4. Offset
The offset error is calculated as the difference between the first bit transition point and the ideal first bit
transition point.
Measurement
1. A number of samples of different production lots that is large enough to ensure statistical significance are selected.
2. The samples are tested by injecting a precise analog signal sweeping from through the entire
ADC range.
3. The first ADC transition point is measured and compared with the ideal value.
4. The maximum difference between the first actual step and the ideal one (in LSBs) represents
the offset error for the sample.
5.6.5. Full-Scale
The full-scale error is calculated as the difference between the last bit transition point measured and the
ideal last bit transition point in LSBs.
Measurement
1. A number of samples of different production lots that is large enough to ensure statistical significance are selected.
2. The samples are tested by injecting a precise analog signal sweeping from through the entire
ADC range.
3. The last ADC transition point is measured and compared with the ideal value
4. The maximum difference between the last actual step and the ideal one (in LSBs) represents
the full scale error for the sample.
5.6.6. Signal to Noise Plus Distortion
The Signal to Noise plus Distortion is the ratio of the RMS signal amplitude (10 kHz single ended sinewave input set to 1 dB below full scale) to the RMS sum of all other spectral components, including the harmonics but excluding dc.
58
Rev. 0.3
C8051F52x-53x
5.6.7. Total Harmonic Distortion (THD)
The total harmonic distortion is the ratio of the sum of the powers of the first five harmonics of the fundamental frequency (10 kHz single ended sine-wave input set to 1 dB below full scale) in dB. The following
formula defines THD:
2
2
2
2
2
Ah1 + Ah2 + Ah3 + Ah4 + Ah5
THD = ---------------------------------------------------------------------------------------------Af
Where Ahn is the amplitude of the n-th harmonic of the fundamental frequency and Af is the amplitude of
the fundamental frequency.
5.6.8. Spurious Free Dynamic Range (SFDR)
The spurious free dynamic range measures the ratio in amplitude of the fundamental signal (10 kHz single
ended sine-wave input set to 1 dB below full scale) and the largest spur (harmonic or not) from dc to half of
the sampling rate (Nyquist Rate) in dB.
Rev. 0.3
59
C8051F52x-53x
Table 5.1. ADC0 Electrical Characteristics (VDD = 2.6 V, VREF = 1.5 V)
VDD = 2.6 V, VREF = 1.5 V (REFSL=0), –40 to +125 °C unless otherwise specified.
Parameter
DC Accuracy
Resolution
Conditions
Min
Typ
Max
12
C8051F52x/C8051F53x
devices
Guaranteed Monotonic
Integral Nonlinearity
—
—
Units
bits
±1
LSB
Differential Nonlinearity
—
—
±1
LSB
Offset Error
—
±1
—
LSB
Full Scale Error
—
±1
—
LSB
Dynamic Performance (10 kHz sine-wave Single-ended input, 0 to 1 dB below Full Scale, 200 ksps)
C8051F52x/C8051F53x
68
—
—
Signal-to-Noise Plus Distortion
dB
devices
64
—
—
Up to the 5th harmonic
Total Harmonic Distortion
Spurious-Free Dynamic Range
Conversion Rate
SAR Conversion Clock
Conversion Time in SAR Clocks
1
2
Track/Hold Acquisition Time
Throughput Rate
Analog Inputs
—
76
—
dB
—
91
—
dB
—
—
10
MHz
—
13
—
clocks
1
—
—
µs
—
—
200
ksps
Input Voltage Range3
Input Capacitance
Temperature Sensor
0
—
4.6 or 2.3
V
—
12
—
pF
Linearity4,5
—
0.1
—
°C
Gain4,5
—
2.89
—
mV/°C
(Temp = 25 °C)
—
888
—
mV
Operating Mode, 200 ksps
—
840
—
µA
—
—
880
1
—
—
µA
mV/V
Offset4,5
Power Specifications
Power Supply Current
(VDD supplied to ADC)
Burst Mode (Idle)
Power Supply Rejection
Notes:
1. An additional 2 FCLK cycles are required to start and complete a conversion.
2. Additional tracking time may be required depending on the output impedance connected to the ADC input.
See Section “5.3.6. Settling Time Requirements” on page 48.
3. The maximum input voltage is 2.3 V without attenuation and 4.6 V with attenuation when using the internal
reference. If an external reference is used then the input is limited to the external reference value.
4. Represents one standard deviation from the mean.
5. Includes ADC offset, gain, and linearity variations.
60
Rev. 0.3
C8051F52x-53x
Table 5.2. ADC0 Electrical Characteristics (VDD = 2.1 V, VREF = 1.5 V)
VDD = 2.1 V, VREF = 1.5 V (REFSL = 0), –40 to +125 °C unless otherwise specified
Parameter
Conditions
Min
Typ
Max
Units
DC Accuracy
Resolution
12
bits
Integral Nonlinearity
C8051F52x/C8051F53x
devices
—
—
±1
LSB
Differential Nonlinearity
Guaranteed Monotonic
—
—
±1
LSB
Offset Error
—
±1
—
LSB
Full Scale Error
—
±1
—
LSB
Dynamic Performance (10 kHz sine-wave Single-ended input, 0 to 1 dB below Full Scale, 200 ksps)
Signal-to-Noise Plus Distortion
C8051F52x/C8051F53x
devices
68
—
—
dB
Total Harmonic Distortion
Up to the 5th harmonic
—
76
—
dB
—
91
—
dB
—
—
10
MHz
—
13
—
clocks
Spurious-Free Dynamic Range
Conversion Rate
SAR Conversion Clock
Conversion Time in SAR Clocks
Note 1
Track/Hold Acquisition Time
Note 2
1
—
—
µs
—
—
200
ksps
Input Voltage Range
0
—
4.6 or 2.3
V
Input Capacitance
—
12
—
pF
Throughput Rate
Analog Inputs
Temperature Sensor
Linearity
Notes 3, 4
—
0.1
—
°C
Gain
Notes 3, 4
—
2.89
—
µV / °C
Offset
Notes 3, 4 (Temp = 0 °C)
—
888
—
mV
Operating Mode, 200 ksps
—
840
—
µA
—
880
—
µA
TBD
—
—
µs
—
TBD
—
mV/V
Power Specifications
Power Supply Current (VDD supplied to ADC0)
Burst Mode (Idle)
Power-On Time
Power Supply Rejection
Notes:
1. An additional 2 FCLK cycles are required to start and complete a conversion.
2. Additional tracking time may be required depending on the output impedance connected to the ADC input.
See Section “5.3.6. Settling Time Requirements” on page 48.
3. Represents one standard deviation from the mean.
4. Includes ADC offset, gain, and linearity variations.
Rev. 0.3
61
C8051F52x-53x
NOTES:
62
Rev. 0.3
C8051F52x-53x
6.
Voltage Reference
The Voltage reference MUX on C8051F52x/F53x devices is configurable to use an externally connected
voltage reference, the internal reference voltage generator, or the VDD power supply voltage (see
Figure 6.1). The REFSL bit in the Reference Control register (REF0CN) selects the reference source. For
an external source or the internal reference applied to the VREF pin, REFSL should be set to ‘0’. To use
VDD as the reference source, REFSL should be set to ‘1’.
The BIASE bit enables the internal voltage bias generator, which is used by the ADC, Temperature Sensor,
and internal oscillators. This bit is forced to logic 1 when any of the aforementioned peripherals are
enabled. The bias generator may be enabled manually by writing a ‘1’ to the BIASE bit in register
REF0CN; see SFR Definition 6.1 for REF0CN register details. The electrical specifications for the voltage
reference circuit are given in Table 6.1.
The internal voltage reference circuit consists of a temperature stable bandgap voltage reference generator and a gain-of-two output buffer amplifier. The output voltage is selectable between 1.5 V and 2.25 V.
The internal voltage reference can be driven out on the VREF pin by setting the REFBE bit in register
REF0CN to a ‘1’ (see Figure 6.1). The load seen by the VREF pin must draw less than 200 µA to GND.
When using the internal voltage reference, bypass capacitors of 0.1 µF and 4.7 µF are recommended from
the VREF pin to GND. If the internal reference is not used, the REFBE bit should be cleared to ‘0’. Electrical
specifications for the internal voltage reference are given in Table 6.1.
REFLV
REFSL
TEMPE
BIASE
REFBE
REF0CN
EN
Bias Generator
To ADC,
Internal Oscillators
IOSCEN
VDD
R1
External
Voltage
Reference
Circuit
EN
VREF
Temp Sensor
To Analog Mux
0
VREF
(to ADC)
GND
VDD
1
REFBE
EN
Internal
Reference
REFLV
Figure 6.1. Voltage Reference Functional Block Diagram
Rev. 0.3
63
C8051F52x-53x
Important Note About the VREF Pin: Port pin P0.0 is used as the external VREF input and as an output for
the internal VREF. When using either an external voltage reference or the internal reference circuitry, P0.0
should be configured as an analog pin, and skipped by the Digital Crossbar. To configure P0.0 as an analog pin, clear Bit 2 in register P0MDIN to ‘0’. To configure the Crossbar to skip P0.0, set Bit 0 in register
P0SKIP to ‘1’. Refer to Section “14. Port Input/Output” on page 117 for complete Port I/O configuration
details. The TEMPE bit in register REF0CN enables/disables the temperature sensor. While disabled, the
temperature sensor defaults to a high impedance state and any ADC0 measurements performed on the
sensor result in meaningless data.
SFR Definition 6.1. REF0CN: Reference Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
—
—
ZTCEN
REFLV
REFSL
TEMPE
BIASE
REFBE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
0xD1
Bits7–6: RESERVED. Read = 0b. Must write 0b.
Bit5:
ZTCEN: Zero-TempCo Bias Enable Bit.
0: ZeroTC Bias Generator automatically enabled when needed.
1: ZeroTC Bias Generator forced on.
Bit4:
REFLV: Voltage Reference Output Level Select.
This bit selects the output voltage level for the internal voltage reference.
0: Internal voltage reference set to 1.5 V.
1: Internal voltage reference set to 2.25 V.
Bit3:
REFSL: Voltage Reference Select.
This bit selects the source for the internal voltage reference.
0: VREF pin used as voltage reference.
1: VDD used as voltage reference.
Bit2:
TEMPE: Temperature Sensor Enable Bit.
0: Internal Temperature Sensor off.
1: Internal Temperature Sensor on.
Bit1:
BIASE: Internal Analog Bias Generator Enable Bit.
0: Internal Analog Bias Generator automatically enabled when needed.
1: Internal Analog Bias Generator on.
Bit0:
REFBE: Internal Reference Buffer Enable Bit.
0: Internal Reference Buffer disabled.
1: Internal Reference Buffer enabled. Internal voltage reference driven on the VREF pin.
64
Rev. 0.3
C8051F52x-53x
Table 6.1. Voltage Reference Electrical Characteristics
VDD = 2.1 V; –40 to +125 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
25 °C ambient (REFLV = 0)
25 °C ambient (REFLV = 1), VDD = 2.6 V
TBD
TBD
1.5
2.2
TBD
TBD
V
VREF Short-Circuit Current
—
—
TBD
mA
VREF Temperature Coefficient
—
33
—
ppm/°C
Power Consumption (Internal)
—
30
—
µA
Internal Reference (REFBE = 1)
Output Voltage
Load Regulation
Load = 0 to 200 µA to GND
—
10
—
ppm/µA
VREF Turn-on Time 1
4.7 µF tantalum, 0.1 µF ceramic bypass
—
TBD
—
ms
VREF Turn-on Time 2
no bypass cap
—
TBD
—
µs
—
TBD
—
ppm/V
0
—
VDD
V
Sample Rate = 200 ksps; VREF = TBD V
—
TBD
—
µA
BIASE = ‘1’
—
30
—
µA
Power Supply Rejection
External Reference (REFBE = 0)
Input Voltage Range
Input Current
Bias Generators
ADC Bias Generator
Rev. 0.3
65
C8051F52x-53x
NOTES:
66
Rev. 0.3
C8051F52x-53x
7.
Voltage Regulator (REG0)
C8051F52x/F53x devices include an on-chip low dropout voltage regulator (REG0). The input to REG0 at
the VREGIN pin can be as high as 5.25 V. The output can be selected by software to 2.1 V or 2.6 V. When
enabled, the output of REG0 appears on the VDD pin, powers the microcontroller core, and can be used to
power external devices. On reset, REG0 is enabled and can be disabled by software.
The input (VREGIN) and output (VDD) of the voltage regulator should both be bypassed with a large capacitor (4.7 µF + 0.1 µF) to ground. This capacitor will eliminate power spikes and provide any immediate
power required by the microcontroller. The settling time associated with the voltage regulator is shown in
Table 7.1.
The Voltage regulator can also generate an interrupt (if enabled by EREG0, EIE1.6) that is triggered whenever the Vregin Input voltage drops below the dropout threshold. (see Table 7.1)
This dropout interrupt has no pending flag and the recommended procedure to use it is as follows:
Step 1. Wait enough time to ensure the Vregin input voltage is stable
Step 2. Enable the dropout interrupt (EREG0, EIE1.6) and select the proper priority (PREG0,
PIE1.6)
Step 3. If triggered, inside the interrupt disable it (clear EREG0, EIE1.6), execute all procedures
necessary to protect your application (put it in a safe mode and leave the interrupt now
disabled.
Step 4. In the main application, now running in the safe mode, regularly checks the DROPOUT bit
(REG0CN.0). Once it is cleared by the regulator hardware the application can enable the
interrupt again (EREG0, EIE1.6) and return to the normal mode operation.
VREGIN
REG0
.1 µF
4.7 µF
VDD
VDD
4.7 µF
.1 µF
Figure 7.1. External Capacitors for Voltage Regulator Input/Output
Rev. 0.3
67
C8051F52x-53x
SFR Definition 7.1. REG0CN: Regulator Control
R/W
R/W
REGDIS Reserved
Bit7
Bit6
R
R/W
R
R
R
—
REG0MD
—
—
—
R
Bit5
Bit4
Bit3
Bit2
Bit1
Reset Value
DROPOUT 00010000
Bit0
SFR Address: 0xC9
Bit7:
REGDIS: Voltage Regulator Disable Bit.
This bit disables/enables the Voltage Regulator.
0: Voltage Regulator Enabled.
1: Voltage Regulator Disabled.
Bit6:
RESERVED. Read = 0b. Must write 0b.
Bit5:
UNUSED. Read = 0b. Write = don’t care.
Bit4:
REG0MD: Voltage Regulator Mode Select Bit.
This bit selects the Voltage Regulator output voltage.
0: Voltage Regulator output is 2.1 V.
1: Voltage Regulator output is 2.6 V (default).
Bits3–1: UNUSED. Read = 0b. Write = don’t care.
Bit0:
DROPOUT: Voltage Regulator Dropout Indicator Bit.
0: Voltage Regulator is not in dropout.
1: Voltage Regulator is in or near dropout.
Table 7.1. Voltage Regulator Electrical Specifications
VDD = 2.1 or 2.6 V; –40 to +125 °C unless otherwise specified.
Parameter
Conditions
Input Voltage Range (VREGIN)*
Min
Typ
Max
Units
2.7*
—
5.25
V
Dropout Voltage (VDO)
Output Current = 1 mA
Output Current = 50 mA
TBD
TBD
10
500
TBD
TBD
mV
Output Voltage (VDD)
2.1 V operation (REG0MD = ‘0’)
2.6 V operation (REG0MD = ‘1’)
Output Current = 1 to 50 mA
TBD
TBD
—
2.1
2.6
—
TBD
TBD
—
V
Bias Current
2.1 V operation (REG0MD = ‘0’)
2.6 V operation (REG0MD = ‘1’)
—
—
1
1
TBD
TBD
µA
TBD
—
TBD
V
—
18
—
mV/ºC
—
250
—
µs
Dropout Indicator Detection
Threshold
Output Voltage Tempco
VREG Settling Time
50 mA load with VREGIN = 2.4 V and
VDD load capacitor of 4.8 µF
*Note: The minimum input voltage is 2.7 V or VDD + VDO(max load), whichever is greater.
68
Rev. 0.3
C8051F52x-53x
8.
Comparator
C8051F52x/F53x devices include one on-chip programmable voltage comparator. The Comparator is
shown in Figure 8.1;
The Comparator offers programmable response time and hysteresis, an analog input multiplexer, and two
outputs that are optionally available at the Port pins: a synchronous “latched” output (CP0), or an asynchronous “raw” output (CP0A). The asynchronous CP0A signal is available even when the system clock is
not active. This allows the Comparator to operate and generate an output with the device in STOP or SUSPEND mode. When assigned to a Port pin, the Comparator output may be configured as open drain or
push-pull (see Section “14.2. Port I/O Initialization” on page 123). The Comparator may also be used as a
reset source (see Section “12.5. Comparator Reset” on page 102).
The Comparator inputs are selected in the CPT0MX register (SFR Definition 8.2). The CMX0P3–CMX0P0
bits select the Comparator0 positive input; the CMX0N3–CMX0N0 bits select the Comparator0 negative
input.
Important Note About Comparator Inputs: The Port pins selected as Comparator inputs should be configured as analog inputs in their associated Port configuration register, and configured to be skipped by the
Crossbar (for details on Port configuration, see Section “14.3. General Purpose Port I/O” on page 125).
CMX0N3
CMX0N2
CMX0N1
CMX0N0
CMX0P3
CMX0P2
CMX0P1
CMX0P0
P0.1
P0.3
P0.5
CPT0CN
CPT0MX
CP0EN
CP0OUT
CP0RIF
CP0FIF
CP0HYP1
CP0HYP0
VDD
CP0
Interrupt
CP0HYN1
CP0HYN0
CP0
Rising-edge
P0.0
CP0
Falling-edge
P0.2
CP0 +
P0.4
Interrupt
Logic
P0.6*
CP0
+
P1.0*
P0.7*
D
-
P1.2*
P1.1*
SET
CLR
D
Q
Q
SET
CLR
Q
Q
Crossbar
P1.4*
(SYNCHRONIZER)
P1.3*
GND
P1.6*
P1.5*
CP0A
Reset
Decision
Tree
P1.7*
*Available in
‘F53x parts
CPT0MD
CP0FIE
CP0RIE
CP0MD1
CP0MD0
CP0 -
Figure 8.1. Comparator Functional Block Diagram
The Comparator has two input modes: Low-Speed Analog Mode and High-Speed Analog Mode. The difference between the two modes is that Comparator input resistance is decreased in High-Speed Analog
Rev. 0.3
69
C8051F52x-53x
Mode, but power consumption is slightly increased. High-Speed Analog Mode is enabled by setting the
CPnHIQE bit in CPTnMD.
The Comparator output can be polled in software, used as an interrupt source, internal oscillator suspend
awakening source and/or routed to a Port pin. When routed to a Port pin, the Comparator output is available asynchronous or synchronous to the system clock; the asynchronous output is available even in
STOP or SUSPEND mode (with no system clock active). When disabled, the Comparator output (if
assigned to a Port I/O pin via the Crossbar) defaults to the logic low state, and its supply current falls to
less than 100 nA. See Section “14.1. Priority Crossbar Decoder” on page 119 for details on configuring
Comparator outputs via the digital Crossbar. Comparator inputs can be externally driven from –0.25 V to
(VDD) + 0.25 V without damage or upset. The complete Comparator electrical specifications are given in
Table 8.1.
The Comparator response time may be configured in software via the CPTnMD register (see SFR Definition 8.3). Selecting a longer response time reduces the Comparator supply current. See Table 8.1 for complete timing and current consumption specifications.
VIN+
VIN-
CP0+
CP0-
+
CP0
_
OUT
CIRCUIT CONFIGURATION
Positive Hysteresis Voltage
(Programmed with CP0HYP Bits)
VIN-
INPUTS
Negative Hysteresis Voltage
(Programmed by CP0HYN Bits)
VIN+
VOH
OUTPUT
VOL
Negative Hysteresis
Disabled
Positive Hysteresis
Disabled
Maximum
Negative Hysteresis
Maximum
Positive Hysteresis
Figure 8.2. Comparator Hysteresis Plot
The Comparator hysteresis is software-programmable via its Comparator Control register CPT0CN (for
n = 0 or 1). The user can program both the amount of hysteresis voltage (referred to the input voltage) and
the positive and negative-going symmetry of this hysteresis around the threshold voltage.
The Comparator hysteresis is programmed using Bits3–0 in the Comparator Control Register CPT0CN
(shown in SFR Definition 8.1). The amount of negative hysteresis voltage is determined by the settings of
the CP0HYN bits. As shown in Table 8.1, settings of 20, 10 or 5 mV of negative hysteresis can be
70
Rev. 0.3
C8051F52x-53x
programmed, or negative hysteresis can be disabled. In a similar way, the amount of positive hysteresis is
determined by the setting the CP0HYP bits.
Comparator interrupts can be generated on both rising-edge and falling-edge output transitions. (For Interrupt enable and priority control, see Section “11. Interrupt Handler” on page 91). The CP0FIF flag is set to
logic 1 upon a Comparator falling-edge detect, and the CPnRIF flag is set to logic 1 upon the Comparator
rising-edge detect. Once set, these bits remain set until cleared by software. The output state of the Comparator can be obtained at any time by reading the CPnOUT bit. The Comparator is enabled by setting the
CP0EN bit to logic 1, and is disabled by clearing this bit to logic 0.
The output state of the Comparator can be obtained at any time by reading the CP0OUT bit. The Comparator is enabled by setting the CP0EN bit to logic 1, and is disabled by clearing this bit to logic 0. When the
Comparator is enabled, the internal oscillator is awakened from SUSPEND mode if the Comparator output
is logic 0.
Note that false rising edges and falling edges can be detected when the comparator is first powered-on or
if changes are made to the hysteresis or response time control bits. Therefore, it is recommended that the
rising-edge and falling-edge flags be explicitly cleared to logic 0 a short time after the comparator is
enabled or its mode bits have been changed. This Power Up Time is specified in Table 8.1 on page 74.
SFR Definition 8.1. CPT0CN: Comparator0 Control
R/W
R
R/W
R/W
CP0EN
CP0OUT
CP0RIF
CP0FIF
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
R/W
Reset Value
CP0HYP1 CP0HYP0 CP0HYN1 CP0HYN0 00000000
Bit3
Bit2
Bit1
Bit0
SFR Address:
0x9B
Bit7:
CP0EN: Comparator0 Enable Bit.
0: Comparator0 Disabled.
1: Comparator0 Enabled.
Bit6:
CP0OUT: Comparator0 Output State Flag.
0: Voltage on CP0+ < CP0–.
1: Voltage on CP0+ > CP0–.
Bit5:
CP0RIF: Comparator0 Rising-Edge Flag.
0: No Comparator0 Rising Edge has occurred since this flag was last cleared.
1: Comparator0 Rising Edge has occurred.
Bit4:
CP0FIF: Comparator0 Falling-Edge Flag.
0: No Comparator0 Falling-Edge has occurred since this flag was last cleared.
1: Comparator0 Falling-Edge has occurred.
Bits3–2: CP0HYP1–0: Comparator0 Positive Hysteresis Control Bits.
00: Positive Hysteresis Disabled.
01: Positive Hysteresis = 5 mV.
10: Positive Hysteresis = 10 mV.
11: Positive Hysteresis = 20 mV.
Bits1–0: CP0HYN1–0: Comparator0 Negative Hysteresis Control Bits.
00: Negative Hysteresis Disabled.
01: Negative Hysteresis = 5 mV.
10: Negative Hysteresis = 10 mV.
11: Negative Hysteresis = 20 mV.
Rev. 0.3
71
C8051F52x-53x
SFR Definition 8.2. CPT0MX: Comparator0 MUX Selection
R/W
R/W
R/W
R/W
R/W
CMX0N3 CMX0N2 CMX0N1 CMX0N0 CMX0P3
Bit7
Bit6
Bit5
Bit4
Bit3
R/W
R/W
R/W
Reset Value
CMX0P2
CMX0P1
CMX0P0
01110111
Bit2
Bit1
Bit0
SFR Address:
0x9F
Bits7–4: CMX0N3–CMX0N0: Comparator0 Negative Input MUX Select.
These bits select which Port pin is used as the Comparator0 negative input.
CMX0N3 CMX0N2 CMX0N1 CMX0N0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
Negative Input
P0.1
P0.3
P0.5
P0.7*
P1.1*
P1.3*
P1.5*
P1.7*
*Note: Available only on the C8051F53x devices
Bits1–0: CMX0P3–CMX0P0: Comparator0 Positive Input MUX Select.
These bits select which Port pin is used as the Comparator0 positive input.
CMX0P3 CMX0P2 CMX0P1 CMX0P0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
*Note: Available only on the C8051F53x devices.
72
Rev. 0.3
Positive Input
P0.0
P0.2
P0.4
P0.6*
P1.0*
P1.2*
P1.4*
P1.6*
C8051F52x-53x
SFR Definition 8.3. CPT0MD: Comparator0 Mode Selection
R/W
R/W
R/W
R/W
R/W
R/W
CP0HIQE
-
CP0RIE
CP0FIE
-
-
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
R/W
R/W
Reset Value
CP0MD1 CP0MD0 00000010
Bit1
Bit0
SFR Address:
0x9D
Bit7:
CP0HIQE: High-Speed Analog Mode Enable Bit.
0: Comparator input configured to Low-Speed Analog Mode.
1: Comparator input configured to High-Speed Analog Mode.
Bit6:
UNUSED. Read = 0b. Write = don’t care.
Bit5:
CP0RIE: Comparator Rising-Edge Interrupt Enable.
0: Comparator rising-edge interrupt disabled.
1: Comparator rising-edge interrupt enabled.
Bit4:
CP0FIE: Comparator Falling-Edge Interrupt Enable.
0: Comparator falling-edge interrupt disabled.
1: Comparator falling-edge interrupt enabled.
Note: It is necessary to enable both CP0xIE and the correspondent ECPx bit located in EIE1
SFR.
Bits3–2: UNUSED. Read = 00b. Write = don’t care.
Bits1–0: CP0MD1–CP0MD0: Comparator0 Mode Select
These bits select the response time for Comparator0.
Mode
CP0MD1
CP0MD0
0
1
2
3
0
0
1
1
0
1
0
1
CP0 Falling Edge Response
Time (TYP)
Fastest Response Time
—
—
Lowest Power Consumption
Note: Rising Edge response times are approximately double the Falling Edge response
times.
Rev. 0.3
73
C8051F52x-53x
Table 8.1. Comparator Electrical Characteristics
VDD = 2.1 V, –40 to +125 °C unless otherwise noted.
All specifications apply to both Comparator0 and Comparator1 unless otherwise noted.
Min
Typ
Max
Units
Response Time:
Mode 0, Vcm1 = 1.5 V
Parameter
CP0+ – CP0– = 100 mV
Conditions
—
780
—
ns
CP0+ – CP0– = –100 mV
—
980
—
ns
Response Time:
Mode 1, Vcm1 = 1.5 V
CP0+ – CP0– = 100 mV
—
850
—
ns
CP0+ – CP0– = –100 mV
—
1120
—
ns
Response Time:
Mode 2, Vcm1 = 1.5 V
CP0+ – CP0– = 100 mV
—
870
—
ns
CP0+ – CP0– = –100 mV
—
1310
—
ns
Response Time:
Mode 3, Vcm1 = 1.5 V
CP0+ – CP0– = 100 mV
—
1980
—
ns
CP0+ – CP0– = –100 mV
—
4770
—
ns
—
1.5
TBD
mV/V
Common-Mode Rejection
Ratio
Positive Hysteresis 1
CP0HYP1-0 = 00
—
0.45
TBD
mV
Positive Hysteresis 2
CP0HYP1-0 = 01
TBD
5
TBD
mV
Positive Hysteresis 3
CP0HYP1-0 = 10
TBD
9.95
TBD
mV
Positive Hysteresis 4
CP0HYP1-0 = 11
TBD
19.47
TBD
mV
Negative Hysteresis 1
CP0HYN1-0 = 00
—
0.45
TBD
mV
Negative Hysteresis 2
CP0HYN1-0 = 01
TBD
4.99
TBD
mV
Negative Hysteresis 3
CP0HYN1-0 = 10
TBD
9.93
TBD
mV
Negative Hysteresis 4
CP0HYN1-0 = 11
TBD
19.41
TBD
mV
–0.25
—
VDD + 0.25
V
—
4
—
pF
Inverting or Non-Inverting
Input Voltage Range
Input Capacitance
Input Bias Current
—
0.5
—
nA
–10
—
10
mV
—
TBD
TBD
—
kΩ
kΩ
Power Supply Rejection2
—
0.2
4
mV/V
Power-up Time
—
2.3
—
µs
High Speed Mode (CP1HIQE = ‘1’)
Low Speed Mode (CP1HIQE = ‘0’)
—
TBD
TBD
—
mA
mA
Mode 0
—
13
TBD
µA
Mode 1
—
6
TBD
µA
Mode 2
—
3
TBD
µA
Mode 3
—
1
TBD
µA
Input Offset Voltage
Input Impedance
High Speed Mode (CP1HIQE = ‘1’)
Low Speed Mode (CP1HIQE = ‘0’)
Power Supply
Power Consumption
Supply Current at DC
Notes:
1. Vcm is the common-mode voltage on CP0+ and CP0–.
2. Guaranteed by design and/or characterization.
74
Rev. 0.3
C8051F52x-53x
9.
CIP-51 Microcontroller
The MCU system controller core is the CIP-51 microcontroller. The CIP-51 is fully compatible with the
MCS-51™ instruction set. Standard 803x/805x assemblers and compilers can be used to develop software. The C8051F52x/C8051F53x family has a superset of all the peripherals included with a standard
8051. See Section “1. System Overview” on page 17 for more information about the available peripherals.
The CIP-51 includes on-chip debug hardware which interfaces directly with the analog and digital subsystems, providing a complete data acquisition or control-system solution in a single integrated circuit.
The CIP-51 Microcontroller core implements the standard 8051 organization and peripherals as well as
additional custom peripherals and functions to extend its capability (see Figure 9.1 for a block diagram).
The CIP-51 core includes the following features:
-
- Fully Compatible with MCS-51 Instruction
Set
- 25 MIPS Peak Throughput
- 256 Bytes of Internal RAM
- Extended Interrupt Handler
Reset Input
Power Management Modes
Integrated Debug Logic
Program and Data Memory Security
DATA BUS
D8
TMP2
B REGISTER
STACK POINTER
SRAM
ADDRESS
REGISTER
PSW
SRAM
(256 X 8)
D8
D8
D8
ALU
D8
D8
TMP1
ACCUMULATOR
D8
D8
D8
DATA BUS
DATA BUS
SFR_ADDRESS
BUFFER
D8
DATA POINTER
D8
D8
SFR
BUS
INTERFACE
SFR_CONTROL
SFR_WRITE_DATA
SFR_READ_DATA
DATA BUS
PC INCREMENTER
PROGRAM COUNTER (PC)
PRGM. ADDRESS REG.
PIPELINE
RESET
MEM_CONTROL
A16
MEMORY
INTERFACE
MEM_WRITE_DATA
MEM_READ_DATA
D8
CONTROL
LOGIC
SYSTEM_IRQs
CLOCK
D8
STOP
IDLE
MEM_ADDRESS
D8
POWER CONTROL
REGISTER
INTERRUPT
INTERFACE
EMULATION_IRQ
D8
Figure 9.1. CIP-51 Block Diagram
Rev. 0.3
75
C8051F52x-53x
Performance
The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system
clock cycles to execute, and usually have a maximum system clock of 12 MHz. By contrast, the CIP-51
core executes 70% of its instructions in one or two system clock cycles, with no instructions taking more
than eight system clock cycles.
With the CIP-51's system clock running at 25 MHz, it has a peak throughput of 25 MIPS. The CIP-51 has a
total of 109 instructions. The table below shows the total number of instructions that require each execution
time.
Clocks to Execute
1
2
2/4
3
3/5
4
5
4/6
6
8
Number of Instructions
26
50
5
10
7
5
2
1
2
1
Programming and Debugging Support
In-system programming of the Flash program memory and communication with on-chip debug support
logic is accomplished via the Silicon Labs 2-Wire (C2) interface. Note that the re-programmable Flash can
also be read and written a single byte at a time by the application software using the MOVC and MOVX
instructions. This feature allows program memory to be used for non-volatile data storage as well as updating program code under software control.
The on-chip debug support logic facilitates full speed in-circuit debugging, allowing the setting of hardware
breakpoints, starting, stopping and single stepping through program execution (including interrupt service
routines), examination of the program's call stack, and reading/writing the contents of registers and memory. This method of on-chip debugging is completely non-intrusive, requiring no RAM, Stack, timers, or
other on-chip resources.
The CIP-51 is supported by development tools from Silicon Laboratories, Inc. and third party vendors. Silicon Laboratories provides an integrated development environment (IDE) including editor, evaluation compiler, assembler, debugger and programmer. The IDE's debugger and programmer interface to the CIP-51
via the on-chip debug logic to provide fast and efficient in-system device programming and debugging.
Third party macro assemblers and C compilers are also available.
9.1.
Instruction Set
The instruction set of the CIP-51 System Controller is fully compatible with the standard MCS-51™ instruction set. Standard 8051 development tools can be used to develop software for the CIP-51. All CIP-51
instructions are the binary and functional equivalent of their MCS-51™ counterparts, including opcodes,
addressing modes and effect on PSW flags. However, instruction timing is different than that of the standard 8051.
9.1.1. Instruction and CPU Timing
In many 8051 implementations, a distinction is made between machine cycles and clock cycles, with
machine cycles varying from 2 to 12 clock cycles in length. However, the CIP-51 implementation is based
solely on clock cycle timing. All instruction timings are specified in terms of clock cycles.
Due to the pipelined architecture of the CIP-51, most instructions execute in the same number of clock
cycles as there are program bytes in the instruction. Conditional branch instructions take two less clock
cycles to complete when the branch is not taken as opposed to when the branch is taken. Table 9.1 is the
CIP-51 Instruction Set Summary, which includes the mnemonic, number of bytes, and number of clock
cycles for each instruction.
76
Rev. 0.3
C8051F52x-53x
9.1.2. MOVX Instruction and Program Memory
The MOVX instruction is typically used to access data stored in XDATA memory space. In the CIP-51, the
MOVX instruction can also be used to write or erase on-chip program memory space implemented as reprogrammable Flash memory. The Flash access feature provides a mechanism for the CIP-51 to update
program code and use the program memory space for non-volatile data storage. Refer to Section
“13. Flash Memory” on page 107 for further details.
Table 9.1. CIP-51 Instruction Set Summary1
Mnemonic
ADD A, Rn
ADD A, direct
ADD A, @Ri
ADD A, #data
ADDC A, Rn
ADDC A, direct
ADDC A, @Ri
ADDC A, #data
SUBB A, Rn
SUBB A, direct
SUBB A, @Ri
SUBB A, #data
INC A
INC Rn
INC direct
INC @Ri
DEC A
DEC Rn
DEC direct
DEC @Ri
INC DPTR
MUL AB
DIV AB
DA A
ANL A, Rn
ANL A, direct
ANL A, @Ri
ANL A, #data
ANL direct, A
ANL direct, #data
ORL A, Rn
ORL A, direct
ORL A, @Ri
ORL A, #data
ORL direct, A
Description
Arithmetic Operations
Add register to A
Add direct byte to A
Add indirect RAM to A
Add immediate to A
Add register to A with carry
Add direct byte to A with carry
Add indirect RAM to A with carry
Add immediate to A with carry
Subtract register from A with borrow
Subtract direct byte from A with borrow
Subtract indirect RAM from A with borrow
Subtract immediate from A with borrow
Increment A
Increment register
Increment direct byte
Increment indirect RAM
Decrement A
Decrement register
Decrement direct byte
Decrement indirect RAM
Increment Data Pointer
Multiply A and B
Divide A by B
Decimal adjust A
Logical Operations
AND Register to A
AND direct byte to A
AND indirect RAM to A
AND immediate to A
AND A to direct byte
AND immediate to direct byte
OR Register to A
OR direct byte to A
OR indirect RAM to A
OR immediate to A
OR A to direct byte
Rev. 0.3
Bytes
Clock
Cycles
1
2
1
2
1
2
1
2
1
2
1
2
1
1
2
1
1
1
2
1
1
1
1
1
1
2
2
2
1
2
2
2
1
2
2
2
1
1
2
2
1
1
2
2
1
4
8
1
1
2
1
2
2
3
1
2
1
2
2
1
2
2
2
2
3
1
2
2
2
2
77
C8051F52x-53x
Table 9.1. CIP-51 Instruction Set Summary1 (Continued)
Mnemonic
ORL direct, #data
XRL A, Rn
XRL A, direct
XRL A, @Ri
XRL A, #data
XRL direct, A
XRL direct, #data
CLR A
CPL A
RL A
RLC A
RR A
RRC A
SWAP A
Description
Bytes
Clock
Cycles
3
1
2
2
2
2
3
1
1
1
1
1
1
1
3
1
2
1
2
2
3
1
1
1
1
1
1
1
MOV A, Rn
MOV A, direct
MOV A, @Ri
MOV A, #data
MOV Rn, A
MOV Rn, direct
MOV Rn, #data
MOV direct, A
MOV direct, Rn
MOV direct, direct
MOV direct, @Ri
MOV direct, #data
MOV @Ri, A
MOV @Ri, direct
MOV @Ri, #data
MOV DPTR, #data16
MOVC A, @A+DPTR
OR immediate to direct byte
Exclusive-OR Register to A
Exclusive-OR direct byte to A
Exclusive-OR indirect RAM to A
Exclusive-OR immediate to A
Exclusive-OR A to direct byte
Exclusive-OR immediate to direct byte
Clear A
Complement A
Rotate A left
Rotate A left through Carry
Rotate A right
Rotate A right through Carry
Swap nibbles of A
Data Transfer
Move Register to A
Move direct byte to A
Move indirect RAM to A
Move immediate to A
Move A to Register
Move direct byte to Register
Move immediate to Register
Move A to direct byte
Move Register to direct byte
Move direct byte to direct byte
Move indirect RAM to direct byte
Move immediate to direct byte
Move A to indirect RAM
Move direct byte to indirect RAM
Move immediate to indirect RAM
Load DPTR with 16-bit constant
Move code byte relative DPTR to A
1
2
1
2
1
2
2
2
2
3
2
3
1
2
2
3
1
4 to 72
MOVC A, @A+PC
MOVX A, @Ri
MOVX @Ri, A
MOVX A, @DPTR
MOVX @DPTR, A
PUSH direct
POP direct
XCH A, Rn
XCH A, direct
XCH A, @Ri
XCHD A, @Ri
Move code byte relative PC to A
Move external data (8-bit address) to A
Move A to external data (8-bit address)
Move external data (16-bit address) to A
Move A to external data (16-bit address)
Push direct byte onto stack
Pop direct byte from stack
Exchange Register with A
Exchange direct byte with A
Exchange indirect RAM with A
Exchange low nibble of indirect RAM with A
1
1
1
1
1
2
2
1
2
1
1
4 to 72
3
3
3
3
2
2
1
2
2
2
78
Rev. 0.3
1
2
2
2
1
2
2
2
2
3
2
3
2
2
2
3
C8051F52x-53x
Table 9.1. CIP-51 Instruction Set Summary1 (Continued)
Mnemonic
CLR C
CLR bit
SETB C
SETB bit
CPL C
CPL bit
ANL C, bit
ANL C, /bit
ORL C, bit
ORL C, /bit
MOV C, bit
MOV bit, C
JC rel
JNC rel
JB bit, rel
JNB bit, rel
JBC bit, rel
ACALL addr11
LCALL addr16
RET
RETI
AJMP addr11
LJMP addr16
SJMP rel
JMP @A+DPTR
JZ rel
JNZ rel
CJNE A, direct, rel
CJNE A, #data, rel
CJNE Rn, #data, rel
CJNE @Ri, #data, rel
DJNZ Rn, rel
DJNZ direct, rel
NOP
Description
Boolean Manipulation
Clear Carry
Clear direct bit
Set Carry
Set direct bit
Complement Carry
Complement direct bit
AND direct bit to Carry
AND complement of direct bit to Carry
OR direct bit to carry
OR complement of direct bit to Carry
Move direct bit to Carry
Move Carry to direct bit
Jump if Carry is set
Jump if Carry is not set
Jump if direct bit is set
Jump if direct bit is not set
Jump if direct bit is set and clear bit
Program Branching
Absolute subroutine call
Long subroutine call
Return from subroutine
Return from interrupt
Absolute jump
Long jump
Short jump (relative address)
Jump indirect relative to DPTR
Jump if A equals zero
Jump if A does not equal zero
Compare direct byte to A and jump if not equal
Compare immediate to A and jump if not equal
Compare immediate to Register and jump if not
equal
Compare immediate to indirect and jump if not
equal
Decrement Register and jump if not zero
Decrement direct byte and jump if not zero
No operation
Bytes
Clock
Cycles
1
2
1
2
1
2
2
2
2
2
2
2
2
2
3
3
3
1
2
1
2
1
2
2
2
2
2
2
2
2/4
2/4
3/5
3/5
3/5
2
3
1
1
2
3
2
1
2
2
3
3
4
5
6
6
4
5
4
4
2/4
2/4
3/5
3/5
3
3/5
3
4/6
2
3
1
2/4
3/5
1
Notes:
1. Assumes PFEN = 1 for all instruction timing.
2. MOVC instructions take 4 to 7 clock cycles depending on instruction alignment and the FLRT setting.
Rev. 0.3
79
C8051F52x-53x
Notes on Registers, Operands and Addressing Modes:
Rn - Register R0–R7 of the currently selected register bank.
@Ri - Data RAM location addressed indirectly through R0 or R1.
rel - 8-bit, signed (two’s complement) offset relative to the first byte of the following instruction. Used by
SJMP and all conditional jumps.
direct - 8-bit internal data location’s address. This could be a direct-access Data RAM location (0x00–
0x7F) or an SFR (0x80–0xFF).
#data - 8-bit constant
#data16 - 16-bit constant
bit - Direct-accessed bit in Data RAM or SFR
addr11 - 11-bit destination address used by ACALL and AJMP. The destination must be within the same
2 kB page of program memory as the first byte of the following instruction.
addr16 - 16-bit destination address used by LCALL and LJMP. The destination may be anywhere within
the 7680 bytes of program memory space.
There is one unused opcode (0xA5) that performs the same function as NOP.
All mnemonics copyrighted © Intel Corporation 1980.
9.2.
Register Descriptions
Following are descriptions of SFRs related to the operation of the CIP-51 System Controller. Reserved bits
should not be set to logic 1. Future product versions may use these bits to implement new features in
which case the reset value of the bit will be logic 0, selecting the feature's default state. Detailed descriptions of the remaining SFRs are included in the sections of the datasheet associated with their corresponding system function.
SFR Definition 9.1. SP: Stack Pointer
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x81
Bits7–0: SP: Stack Pointer.
The Stack Pointer holds the location of the top of the stack. The stack pointer is incremented
before every PUSH operation. The SP register defaults to 0x07 after reset.
80
Rev. 0.3
C8051F52x-53x
SFR Definition 9.2. DPL: Data Pointer Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x82
Bits7–0: DPL: Data Pointer Low.
The DPL register is the low byte of the 16-bit DPTR. DPTR is used to access indirectly
addressed XRAM and Flash memory.
SFR Definition 9.3. DPH: Data Pointer High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x83
Bits7–0: DPH: Data Pointer High.
The DPH register is the high byte of the 16-bit DPTR. DPTR is used to access indirectly
addressed XRAM and Flash memory.
Rev. 0.3
81
C8051F52x-53x
SFR Definition 9.4. PSW: Program Status Word
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
Reset Value
CY
AC
F0
RS1
RS0
OV
F1
PARITY
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xD0
Bit7:
CY: Carry Flag.
This bit is set when the last arithmetic operation resulted in a carry (addition) or a borrow
(subtraction). It is cleared to 0 by all other arithmetic operations.
Bit6:
AC: Auxiliary Carry Flag
This bit is set when the last arithmetic operation resulted in a carry into (addition) or a borrow
from (subtraction) the high order nibble. It is cleared to 0 by all other arithmetic operations.
Bit5:
F0: User Flag 0.
This is a bit-addressable, general purpose flag for use under software control.
Bits4–3: RS1–RS0: Register Bank Select.
These bits select which register bank is used during register accesses.
RS1
0
0
1
1
Bit2:
Bit1:
Bit0:
82
RS0
0
1
0
1
Register Bank
0
1
2
3
Address
0x00–0x07
0x08–0x0F
0x10–0x17
0x18–0x1F
OV: Overflow Flag.
This bit is set to 1 under the following circumstances:
• An ADD, ADDC, or SUBB instruction causes a sign-change overflow.
• A MUL instruction results in an overflow (result is greater than 255).
• A DIV instruction causes a divide-by-zero condition.
The OV bit is cleared to 0 by the ADD, ADDC, SUBB, MUL, and DIV instructions in all other
cases.
F1: User Flag 1.
This is a bit-addressable, general purpose flag for use under software control.
PARITY: Parity Flag.
This bit is set to 1 if the sum of the eight bits in the accumulator is odd and cleared if the sum
is even.
Rev. 0.3
C8051F52x-53x
SFR Definition 9.5. ACC: Accumulator
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
ACC.7
ACC.6
ACC.5
ACC.4
ACC.3
ACC.2
ACC.1
ACC.0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xE0
Bits7–0: ACC: Accumulator.
This register is the accumulator for arithmetic operations.
SFR Definition 9.6. B: B Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
B.7
B.6
B.5
B.4
B.3
B.2
B.1
B.0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xF0
Bits7–0: B: B Register.
This register serves as a second accumulator for certain arithmetic operations.
9.3.
Power Management Modes
The CIP-51 core has two software programmable power management modes: Idle and Stop. Idle mode
halts the CPU while leaving the peripherals and internal clocks active. In Stop mode, the CPU is halted, all
interrupts and timers (except the Missing Clock Detector) are inactive, and the internal oscillator is stopped
(analog peripherals remain in their selected states; the external oscillator is not affected). Since clocks are
running in Idle mode, power consumption is dependent upon the system clock frequency and the number
of peripherals left in active mode before entering Idle. Stop mode consumes the least power. SFR Definition 9.7 describes the Power Control Register (PCON) used to control the CIP-51's power management
modes.
Although the CIP-51 has Idle and Stop modes built in (as with any standard 8051 architecture), power
management of the entire MCU is better accomplished by enabling/disabling individual peripherals as
needed. Each analog peripheral can be disabled when not in use and placed in low power mode. Digital
peripherals, such as timers or serial buses, draw little power when they are not in use. Turning off the oscillators lowers power consumption considerably; however a reset is required to restart the MCU.
Rev. 0.3
83
C8051F52x-53x
9.3.1. Idle Mode
Setting the Idle Mode Select bit (PCON.0) causes the CIP-51 to halt the CPU and enter Idle mode as soon
as the instruction that sets the bit completes execution. All internal registers and memory maintain their
original data. All analog and digital peripherals can remain active during Idle mode.
Idle mode is terminated when an enabled interrupt is asserted or a reset occurs. The assertion of an
enabled interrupt will cause the Idle Mode Selection bit (PCON.0) to be cleared and the CPU to resume
operation. The pending interrupt will be serviced and the next instruction to be executed after the return
from interrupt (RETI) will be the instruction immediately following the one that set the Idle Mode Select bit.
If Idle mode is terminated by an internal or external reset, the CIP-51 performs a normal reset sequence
and begins program execution at address 0x0000.
If enabled, the Watchdog Timer (WDT) will eventually cause an internal watchdog reset and thereby terminate the Idle mode. This feature protects the system from an unintended permanent shutdown in the event
of an inadvertent write to the PCON register. If this behavior is not desired, the WDT may be disabled by
software prior to entering the Idle mode if the WDT was initially configured to allow this operation. This provides the opportunity for additional power savings, allowing the system to remain in the Idle mode indefinitely, waiting for an external stimulus to wake up the system.
9.3.2. Stop Mode
Setting the Stop Mode Select bit (PCON.1) causes the CIP-51 to enter Stop mode as soon as the instruction that sets the bit completes execution. In Stop mode the internal oscillator, CPU, and all digital peripherals are stopped; the state of the external oscillator circuit is not affected. Each analog peripheral (including
the external oscillator circuit) may be shut down individually prior to entering Stop Mode. Stop mode can
only be terminated by an internal or external reset. On reset, the CIP-51 performs the normal reset
sequence and begins program execution at address 0x0000.
If enabled, the Missing Clock Detector will cause an internal reset and thereby terminate the Stop mode.
The Missing Clock Detector should be disabled if the CPU is to be put to in STOP mode for longer than the
MCD timeout period of 100 µs.
SFR Definition 9.7. PCON: Power Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
-
-
-
-
-
-
STOP
IDLE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x87
Bits7–2: RESERVED.
Bit1:
STOP: STOP Mode Select.
Writing a ‘1’ to this bit will place the CIP-51 into STOP mode. This bit will always read ‘0’.
1: CIP-51 forced into power-down mode. (Turns off internal oscillator).
Bit0:
IDLE: IDLE Mode Select.
Writing a ‘1’ to this bit will place the CIP-51 into IDLE mode. This bit will always read ‘0’.
1: CIP-51 forced into IDLE mode. (Shuts off clock to CPU, but clock to Timers, Interrupts,
and all peripherals remain active.)
84
Rev. 0.3
C8051F52x-53x
10. Memory Organization and SFRs
The memory organization of the C8051F52x/F53x is similar to that of a standard 8051. There are two separate memory spaces: program memory and data memory. Program and data memory share the same
address space but are accessed via different instruction types. The memory map is shown in Figure 10.1.
PROGRAM/DATA MEMORY
(Flash)
DATA MEMORY (RAM)
INTERNAL DATA ADDRESS SPACE
‘F520/1 and ‘F530/1
0x1E00
RESERVED
0x1DFF
0xFF
0x80
0x7F
Upper 128 RAM
(Indirect Addressing
Only)
(Direct and Indirect
Addressing)
7680 Bytes Flash
(In-System
Programmable in 512
Byte Sectors)
0x30
0x2F
0x20
0x1F
0x00
Bit Addressable
Special Function
Register's
(Direct Addressing Only)
Lower 128 RAM
(Direct and Indirect
Addressing)
General Purpose
Registers
0x0000
‘F526/7 and ‘F536/7
‘F523/4 and ‘F533/4
0x1000
RESERVED
RESERVED
0x0800
0x07FF
0x0FFF
4 kB Flash
2 kB Flash
(In-System
Programmable in 512
Byte Sectors)
(In-System
Programmable in 512
Byte Sectors)
0x0000
0x0000
Figure 10.1. Memory Map
10.1. Program Memory
The CIP-51 core has a 64k-byte program memory space. The C8051F520/1 and ‘F530/1 implement 8 kB
of this program memory space as in-system, re-programmable Flash memory, organized in a contiguous
block from addresses 0x0000 to 0x1FFF. Addresses above 0x1DFF are reserved on the 8 kB devices. The
C8051F523/4 and ‘F533/4 implement 4 kB of Flash from addresses 0x0000 to 0x0FFF.The C8051F526/7
and ‘F536/7 implement 2 kB of Flash from addresses 0x0000 to 0x07FF.
Program memory is normally assumed to be read-only. However, the C8051F52x/F53x can write to program memory by setting the Program Store Write Enable bit (PSCTL.0) and using the MOVX write instruction. This feature provides a mechanism for updates to program code and use of the program memory
space for non-volatile data storage. Refer to Section “13. Flash Memory” on page 107 for further details.
Rev. 0.3
85
C8051F52x-53x
10.2. Data Memory
The C8051F52x/F53x includes 256 bytes of internal RAM mapped into the data memory space from 0x00
through 0xFF. The lower 128 bytes of data memory are used for general purpose registers and scratch pad
memory. Either direct or indirect addressing may be used to access the lower 128 bytes of data memory.
Locations 0x00 through 0x1F are addressable as four banks of general purpose registers, each bank consisting of eight byte-wide registers. The next 16 bytes, locations 0x20 through 0x2F, may either be
addressed as bytes or as 128 bit locations accessible with the direct addressing mode.
The upper 128 bytes of data memory are accessible only by indirect addressing. This region occupies the
same address space as the Special Function Registers (SFRs) but is physically separate from the SFR
space. The addressing mode used by an instruction when accessing locations above 0x7F determines
whether the CPU accesses the upper 128 bytes of data memory space or the SFRs. Instructions that use
direct addressing will access the SFR space. Instructions using indirect addressing above 0x7F access the
upper 128 bytes of data memory. Figure 10.1 illustrates the data memory organization of the C8051F52x/
C8051F53x.
10.3. General Purpose Registers
The lower 32 bytes of data memory (locations 0x00 through 0x1F) may be addressed as four banks of
general-purpose registers. Each bank consists of eight byte-wide registers designated R0 through R7.
Only one of these banks may be enabled at a time. Two bits in the program status word, RS0 (PSW.3) and
RS1 (PSW.4), select the active register bank (see description of the PSW in SFR Definition 9.4. PSW: Program Status Word). This allows fast context switching when entering subroutines and interrupt service routines. Indirect addressing modes use registers R0 and R1 as index registers.
10.4. Bit Addressable Locations
In addition to direct access to data memory organized as bytes, the sixteen data memory locations at 0x20
through 0x2F are also accessible as 128 individually addressable bits. Each bit has a bit address from
0x00 to 0x7F. Bit 0 of the byte at 0x20 has bit address 0x00 while bit 7 of the byte at 0x20 has bit address
0x07. Bit 7 of the byte at 0x2F has bit address 0x7F. A bit access is distinguished from a full byte access by
the type of instruction used (bit source or destination operands as opposed to a byte source or destination).
The MCS-51™ assembly language allows an alternate notation for bit addressing of the form XX.B where
XX is the byte address and B is the bit position within the byte. For example, the instruction:
MOV
C, 22.3h
moves the Boolean value at 0x13 (bit 3 of the byte at location 0x22) into the Carry flag.
10.5. Stack
A programmer's stack can be located anywhere in the 256-byte data memory. The stack area is designated using the Stack Pointer (SP, 0x81) SFR. The SP will point to the last location used. The next value
pushed on the stack is placed at SP+1 and then SP is incremented. A reset initializes the stack pointer to
location 0x07. Therefore, the first value pushed on the stack is placed at location 0x08, which is also the
first register (R0) of register bank 1. Thus, if more than one register bank is to be used, the SP should be
initialized to a location in the data memory not being used for data storage. The stack depth can extend up
to 256 bytes.
86
Rev. 0.3
C8051F52x-53x
10.6. Special Function Registers
The direct-access data memory locations from 0x80 to 0xFF constitute the special function registers
(SFRs). The SFRs provide control and data exchange with the CIP-51's resources and peripherals. The
CIP-51 duplicates the SFRs found in a typical 8051 implementation as well as implementing additional
SFRs used to configure and access the sub-systems unique to the MCU. This allows the addition of new
functionality while retaining compatibility with the MCS-51™ instruction set. Table 10.1 lists the SFRs
implemented in the CIP-51 System Controller.
The SFR registers are accessed anytime the direct addressing mode is used to access memory locations
from 0x80 to 0xFF. SFRs with addresses ending in 0x0 or 0x8 (e.g. P0, TCON, IE, etc.) are bit-addressable
as well as byte-addressable. All other SFRs are byte-addressable only. Unoccupied addresses in the SFR
space are reserved for future use. Accessing these areas will have an indeterminate effect and should be
avoided. Refer to the corresponding pages of the data sheet, as indicated in Table 10.2, for a detailed
description of each register.
Table 10.1. Special Function Register (SFR) Memory Map
F8
F0
E8
E0
D8
D0
C8
C0
B8
B0
A8
A0
98
90
88
80
SPI0CN
B
ADC0CN
ACC
PCA0CN
PSW
TMR2CN
IP
OSCIFIN
IE
—
SCON0
P1
TCON
P0
0(8)
PCA0L
PCA0H PCA0CPL0 PCA0CPH0
VDDMON
P0MDIN
P1MDIN
EIP1
PCA0CPL1 PCA0CPH1 PCA0CPL2 PCA0CPH2
RSTSRC
XBR0
XBR1
IT01CF
EIE1
PCA0MD PCA0CPM0 PCA0CPM1 PCA0CPM2
REF0CN
P0SKIP
P1SKIP
P0MAT
REG0CN TMR2RLL TMR2RLH
TMR2L
TMR2H
P1MAT
ADC0GTL ADC0GTH ADC0LTL ADC0LTH P0MASK
ADC0TK
ADC0MX
ADC0CF
ADC0L
ADC0
P1MASK
OSCXCN OSCICN
OSCICL
FLKEY
CLKSEL
SPI0CFG SPI0CKR SPI0DAT P0MDOUT P1MDOUT
SBUF0
CPT0CN
CPT0MD
CPT0MX
LINADDR LINDATA
LINCF
TMOD
TL0
TL1
TH0
TH1
CKCON
PSCTL
SP
DPL
DPH
PCON
1(9)
2(A)
3(B)
4(C)
5(D)
6(E)
7(F)
(bit addressable)
Rev. 0.3
87
C8051F52x-53x
Table 10.2. Special Function Registers
SFRs are listed in alphabetical order. All undefined SFR locations are reserved
Register
Address
Description
Page
ACC
0xE0
Accumulator
83
ADC0CF
0xBC
ADC0 Configuration
50
ADC0CN
0xE8
ADC0 Control
52
ADC0H
0xBE
ADC0
51
ADC0L
0xBD
ADC0
51
ADC0GTH
0xC4
ADC0 Greater-Than Data High Byte
54
ADC0GTL
0xC3
ADC0 Greater-Than Data Low Byte
54
ADC0LTH
0xC6
ADC0 Less-Than Data High Byte
55
ADC0LTL
0xC5
ADC0 Less-Than Data Low Byte
55
ADC0MX
0xBB
ADC0 Channel Select
49
ADC0TK
0xBA
ADC0 Tracking Mode Select
53
B
0xF0
B Register
83
CKCON
0x8E
Clock Control
191
CLKSEL
0xA9
Clock Select
141
CPT0CN
0x9B
Comparator0 Control
71
CPT0MD
0x9D
Comparator0 Mode Selection
73
CPT0MX
0x9F
Comparator0 MUX Selection
72
DPH
0x83
Data Pointer High
81
DPL
0x82
Data Pointer Low
81
EIE1
0xE6
Extended Interrupt Enable 1
95
EIP1
0xF6
Extended Interrupt Priority 1
96
FLKEY
0xB7
Flash Lock and Key
115
IE
0xA8
Interrupt Enable
93
IP
0xB8
Interrupt Priority
94
IT01CF
0xE4
INT0/INT1 Configuration
98
LINADDR
0x92
LIN indirect address pointer
153
LINCF
0x95
LIN master-slave and automatic baud rate selection
153
LINDATA
0x93
LIN indirect data buffer
153
OSCICL
0xB3
Internal Oscillator Calibration
136
OSCICN
0xB2
Internal Oscillator Control
135
OSCXCN
0xB1
External Oscillator Control
140
P0
0x80
Port 0 Latch
126
P0MASK
0xC7
Port 0 Mask
128
P0MAT
0xD7
Port 0 Match
128
P0MDIN
0xF1
Port 0 Input Mode Configuration
126
P0MDOUT
0xA4
Port 0 Output Mode Configuration
127
P0SKIP
0xD4
Port 0 Skip
127
P1
0x90
Port 1 Latch
129
88
Rev. 0.3
C8051F52x-53x
Table 10.2. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved
Register
Description
Page
P1MASK
Address
0xBF
Port 1 Mask
131
P1MAT
0xCF
Port 1 Match
131
P1MDIN
0xF2
Port 1 Input Mode Configuration
129
P1MDOUT
0xA5
Port 1 Output Mode Configuration
130
P1SKIP
0xD5
Port 1 Skip
130
PCA0CN
0xD8
PCA Control
211
PCA0CPH0
0xFC
PCA Capture 0 High
214
PCA0CPH1
0xEA
PCA Capture 1 High
214
PCA0CPH2
0xEC
PCA Capture 2 High
214
PCA0CPL0
0xFB
PCA Capture 0 Low
214
PCA0CPL1
0xE9
PCA Capture 1 Low
214
PCA0CPL2
0xEB
PCA Capture 2 Low
214
PCA0CPM0
0xDA
PCA Module 0 Mode
213
PCA0CPM1
0xDB
PCA Module 1 Mode
213
PCA0CPM2
0xDC
PCA Module 2 Mode
213
PCA0H
0xFA
PCA Counter High
214
PCA0L
0xF9
PCA Counter Low
214
PCA0MD
0xD9
PCA Mode
212
PCON
0x87
Power Control
84
PSCTL
0x8F
Program Store R/W Control
115
PSW
0xD0
Program Status Word
82
REF0CN
0xD1
Voltage Reference Control
64
REG0CN
0xC9
Voltage Regulator Control
68
RSTSRC
0xEF
Reset Source Configuration/Status
104
SBUF0
0x99
UART0 Data Buffer
149
SCON0
0x98
UART0 Control
148
SP
0x81
Stack Pointer
80
SPI0CFG
0xA1
SPI Configuration
177
SPI0CKR
0xA2
SPI Clock Rate Control
179
SPI0CN
0xF8
SPI Control
178
SPI0DAT
0xA3
SPI Data
180
TCON
0x88
Timer/Counter Control
189
TH0
0x8C
Timer/Counter 0 High
192
TH1
0x8D
Timer/Counter 1 High
192
TL0
0x8A
Timer/Counter 0 Low
192
TL1
0x8B
Timer/Counter 1 Low
192
TMOD
0x89
Timer/Counter Mode
190
TMR2CN
0xC8
Timer/Counter 2 Control
196
Rev. 0.3
89
C8051F52x-53x
Table 10.2. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved
Register
Address
Description
Page
TMR2H
0xCD
Timer/Counter 2 High
197
TMR2L
0xCC
Timer/Counter 2 Low
197
TMR2RLH
0xCB
Timer/Counter 2 Reload High
197
TMR2RLL
0xCA
Timer/Counter 2 Reload Low
197
VDDMON
0xFF
VDD Monitor Control
102
XBR0
0xE1
Port I/O Crossbar Control 0
124
XBR1
0xE2
Port I/O Crossbar Control 1
125
90
Rev. 0.3
C8051F52x-53x
11. Interrupt Handler
The C8051F52x/F53x family includes an extended interrupt system with two selectable priority levels. The
allocation of interrupt sources between on-chip peripherals and external input pins varies according to the
specific version of the device. Each interrupt source has one or more associated interrupt-pending flag(s)
located in an SFR. When a peripheral or external source meets a valid interrupt condition, the associated
interrupt-pending flag is set to logic 1.
If interrupts are enabled for the source, an interrupt request is generated when the interrupt-pending flag is
set. As soon as execution of the current instruction is complete, the CPU generates an LCALL to a predetermined address to begin execution of an interrupt service routine (ISR). Each ISR must end with an RETI
instruction, which returns program execution to the next instruction that would have been executed if the
interrupt request had not occurred. If interrupts are not enabled, the interrupt-pending flag is ignored by the
hardware and program execution continues as normal. (The interrupt-pending flag is set to logic 1 regardless of the interrupt's enable/disable state.)
Each interrupt source can be individually enabled or disabled through the use of an associated interrupt
enable bit in the Interrupt Enable and Extended Interrupt Enable SFRs. However, interrupts must first be
globally enabled by setting the EA bit (IE.7) to logic 1 before the individual interrupt enables are recognized. Setting the EA bit to logic 0 disables all interrupt sources regardless of the individual interruptenable settings. Note that interrupts which occur when the EA bit is set to logic 0 will be held in a pending
state, and will not be serviced until the EA bit is set back to logic 1.
Some interrupt-pending flags are automatically cleared by the hardware when the CPU vectors to the ISR.
However, most are not cleared by the hardware and must be cleared by software before returning from the
ISR. If an interrupt-pending flag remains set after the CPU completes the return-from-interrupt (RETI)
instruction, a new interrupt request will be generated immediately and the CPU will re-enter the ISR after
the completion of the next instruction.
11.1. MCU Interrupt Sources and Vectors
The MCUs support 15 interrupt sources. Software can simulate an interrupt by setting any interrupt-pending flag to logic 1. If interrupts are enabled for the flag, an interrupt request will be generated and the CPU
will vector to the ISR address associated with the interrupt-pending flag. MCU interrupt sources, associated vector addresses, priority order, and control bits are summarized in Table 11.1 on page 92. Refer to
the data sheet section associated with a particular on-chip peripheral for information regarding valid interrupt conditions for the peripheral and the behavior of its interrupt-pending flag(s).
11.2. Interrupt Priorities
Each interrupt source can be individually programmed to one of two priority levels: low or high. A low priority interrupt service routine can be preempted by a high priority interrupt. A high priority interrupt cannot be
preempted. Each interrupt has an associated interrupt priority bit in an SFR (IP or EIP1) used to configure
its priority level. Low priority is the default. If two interrupts are recognized simultaneously, the interrupt with
the higher priority is serviced first. If both interrupts have the same priority level, a fixed priority order is
used to arbitrate, given in Table 11.1.
11.3. Interrupt Latency
Interrupt response time depends on the state of the CPU when the interrupt occurs. Pending interrupts are
sampled and priority decoded each system clock cycle. Therefore, the fastest possible response time is 7
system clock cycles: 1 clock cycle to detect the interrupt, 1 clock cycle to execute a single instruction, and
5 clock cycles to complete the LCALL to the ISR. If an interrupt is pending when a RETI is executed, a single instruction is executed before an LCALL is made to service the pending interrupt. Therefore, the maximum response time for an interrupt (when no other interrupt is currently being serviced or the new interrupt
is of greater priority) occurs when the CPU is performing an RETI instruction followed by a DIV as the next
Rev. 0.3
91
C8051F52x-53x
instruction. In this case, the response time is 19 system clock cycles: 1 clock cycle to detect the interrupt,
5 clock cycles to execute the RETI, 8 clock cycles to complete the DIV instruction and 5 clock cycles to execute the LCALL to the ISR. If the CPU is executing an ISR for an interrupt with equal or higher priority, the
new interrupt will not be serviced until the current ISR completes, including the RETI and following instruction.
Interrupt Priority
Pending Flag
Vector
Order
Reset
0x0000
Top
External Interrupt 0(/INT0)
Timer 0 Overflow
External Interrupt 1(/INT1)
Timer 1 Overflow
0x0003
0x000B
0x0013
0x001B
0
1
2
3
UART
0x0023
4
Timer 2 Overflow
0x002B
5
SPI0
0x0033
6
ADC0 Window
Comparator
0x003B
7
ADC0 End of Conversion
0x0043
8
Programmable Counter
Array
0x004B
9
Comparator Falling Edge
0x0053
10
Comparator Rising Edge
0x005B
11
LIN Interrupt
0x0063
12
Voltage Regulator Dropout 0x006B
13
Port Match
14
0x0073
None
IE0 (TCON.1)
TF0 (TCON.5)
IE1 (TCON.3)
TF1 (TCON.7)
RI0 (SCON0.0)
TI0 (SCON0.1)
TF2H (TMR2CN.7)
TF2L (TMR2CN.6)
SPIF (SPI0CN.7)
WCOL (SPI0CN.6)
MODF (SPI0CN.5)
RXOVRN (SPI0CN.4)
AD0WINT
(ADC0CN.3)
Enable
Flag
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
ES0 (IE.4)
PS0 (IP.4)
Y
N
ET2 (IE.5)
PT2 (IP.5)
Y
N
ESPI0
(IE.6)
PSPI0
(IP.6)
EWADC0
(EIE1.0)
EADC0
AD0INT (ADC0CN.5) Y
N
(EIE1.1)
CF (PCA0CN.7)
EPCA0
Y
N
(EIE1.2)
CCFn (PCA0CN.n)
ECPF
CP0FIF (CPT0CN.4)
N
N
(EIE1.3)
ECPR
CP0RIF (CPT0CN.5)
N
N
(EIE1.4)
ELIN
LININT (LINST.3)
N N*
(EIE1.5)
EREG0
N/A
N/A N/A
(EIE1.6)
EMAT
N/A
N/A N/A
(EIE1.7)
Rev. 0.3
Priority
Control
Always
Enabled
EX0 (IE.0)
ET0 (IE.1)
EX1 (IE.2)
ET1 (IE.3)
N/A N/A
Y
*Note: To clear LININT requires the application to set the RSTINT bit (LINCTRL.3)
92
Cleared by HW?
Interrupt Source
Bit addressable?
Table 11.1. Interrupt Summary
N
Always
Highest
PX0 (IP.0)
PT0 (IP.1)
PX1 (IP.2)
PT1 (IP.3)
PWADC0
(EIP1.0)
PADC0
(EIP1.1)
PPCA0
(EIP1.2)
PCPF
(EIP1.3)
PCPR
(EIP1.4)
PLIN
(EIP1.5)
PREG0
(EIP1.6)
PMAT
(EIP1.7)
C8051F52x-53x
11.4. Interrupt Register Descriptions
The SFRs used to enable the interrupt sources and set their priority level are described below. Refer to the
data sheet section associated with a particular on-chip peripheral for information regarding valid interrupt
conditions for the peripheral and the behavior of its interrupt-pending flag(s).
SFR Definition 11.1. IE: Interrupt Enable
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
EA
ESPI0
ET2
ES0
ET1
EX1
ET0
EX0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xA8
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
EA: Global Interrupt Enable.
This bit globally enables/disables all interrupts. It overrides the individual interrupt mask settings.
0: Disable all interrupt sources.
1: Enable each interrupt according to its individual mask setting.
ESPI0: Enable Serial Peripheral Interface (SPI0) Interrupt.
This bit sets the masking of the SPI0 interrupts.
0: Disable all SPI0 interrupts.
1: Enable interrupt requests generated by SPI0.
ET2: Enable Timer 2 Interrupt.
This bit sets the masking of the Timer 2 interrupt.
0: Disable Timer 2 interrupt.
1: Enable interrupt requests generated by the TF2L or TF2H flags.
ES0: Enable UART0 Interrupt.
This bit sets the masking of the UART0 interrupt.
0: Disable UART0 interrupt.
1: Enable UART0 interrupt.
ET1: Enable Timer 1 Interrupt.
This bit sets the masking of the Timer 1 interrupt.
0: Disable all Timer 1 interrupt.
1: Enable interrupt requests generated by the TF1 flag.
EX1: Enable External Interrupt 1.
This bit sets the masking of the external interrupt 1.
0: Disable external interrupt 1.
1: Enable extern interrupt 1 requests.
ET0: Enable Timer 0 Interrupt.
This bit sets the masking of the Timer 0 interrupt.
0: Disable all Timer 0 interrupt.
1: Enable interrupt requests generated by the TF0 flag.
EX0: Enable External Interrupt 0.
This bit sets the masking of the external interrupt 0.
0: Disable external interrupt 0.
1: Enable extern interrupt 0 requests.
Rev. 0.3
93
C8051F52x-53x
SFR Definition 11.2. IP: Interrupt Priority
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
-
PSPI0
PT2
PS0
PT1
PX1
PT0
PX0
10000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xB8
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
94
UNUSED. Read = 1, Write = don't care.
PSPI0: Serial Peripheral Interface (SPI0) Interrupt Priority Control.
This bit sets the priority of the SPI0 interrupt.
0: SPI0 interrupt set to low priority level.
1: SPI0 interrupt set to high priority level.
PT2: Timer 2 Interrupt Priority Control.
This bit sets the priority of the Timer 2 interrupt.
0: Timer 2 interrupt set to low priority level.
1: Timer 2 interrupt set to high priority level.
PS0: UART0 Interrupt Priority Control.
This bit sets the priority of the UART0 interrupt.
0: UART0 interrupt set to low priority level.
1: UART0 interrupt set to high priority level.
PT1: Timer 1 Interrupt Priority Control.
This bit sets the priority of the Timer 1 interrupt.
0: Timer 1 interrupt set to low priority level.
1: Timer 1 interrupt set to high priority level.
PX1: External Interrupt 0 Priority Control.
This bit sets the priority of the external interrupt 0.
0: Int 0 interrupt set to low priority level.
1: Int 0 interrupt set to high priority level.
PT0: Timer 0 Interrupt Priority Control.
This bit sets the priority of the Timer 0 interrupt.
0: Timer 0 interrupt set to low priority level.
1: Timer 0 interrupt set to high priority level.
PX0: External Interrupt 0 Priority Control.
This bit sets the priority of the external interrupt 0.
0: Int 0 interrupt set to low priority level.
1: Int 0 interrupt set to high priority level.
Rev. 0.3
C8051F52x-53x
SFR Definition 11.3. EIE1: Extended Interrupt Enable 1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
EMAT
EREG0
ELIN
ECPR
ECPF
EPCA0
EADC0
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
EWADC0 00000000
Bit0
SFR Address: 0xE6
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
EMAT: Enable Port Match Interrupt.
This bit sets the masking of the Port Match interrupt.
0: Disable the Port Match interrupt.
1: Enable the Port Match interrupt.
EREG0: Enable Voltage Regulator Interrupt.
This bit sets the masking of the Voltage Regulator Dropout interrupt.
0: Disable the Voltage Regulator Dropout interrupt.
1: Enable the Voltage Regulator Dropout interrupt.
ELIN: Enable LIN Interrupt.
This bit sets the masking of the LIN interrupt.
0: Disable LIN interrupts.
1: Enable LIN interrupt requests.
ECPR: Enable Comparator 0 Rising Edge Interrupt
This bit sets the masking of the CP0 Rising Edge interrupt.
0: Disable CP0 Rising Edge Interrupt.
1: Enable CP0 Rising Edge Interrupt.
ECPF: Enable Comparator 0 Falling Edge Interrupt
This bit sets the masking of the CP0 Falling Edge interrupt.
0: Disable CP0 Falling Edge Interrupt.
1: Enable CP0 Falling Edge Interrupt.
EPCA0: Enable Programmable Counter Array (PCA0) Interrupt.
This bit sets the masking of the PCA0 interrupts.
0: Disable all PCA0 interrupts.
1: Enable interrupt requests generated by PCA0.
EADC0: Enable ADC0 Conversion Complete Interrupt.
This bit sets the masking of the ADC0 Conversion Complete interrupt.
0: Disable ADC0 Conversion Complete interrupt.
1: Enable interrupt requests generated by the AD0INT flag.
EWADC0: Enable ADC0 Window Comparison Interrupt.
This bit sets the masking of the ADC0 Window Comparison interrupt.
0: Disable ADC0 Window Comparison interrupt.
1: Enable interrupt requests generated by the AD0WINT flag.
Rev. 0.3
95
C8051F52x-53x
SFR Definition 11.4. EIP1: Extended Interrupt Priority 1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
PMAT
PREG0
PLIN
PCPR
PCPF
PPAC0
PREG0
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
PWADC0 00000000
Bit0
SFR Address: 0xF6
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
96
PMAT. Port Match Interrupt Priority Control.
This bit sets the priority of the Port Match interrupt.
0: Port Match interrupt set to low priority level.
1: Port Match interrupt set to high priority level.
PREG0: Voltage Regulator Interrupt Priority Control.
This bit sets the priority of the Voltage Regulator interrupt.
0: Voltage Regulator interrupt set to low priority level.
1: Voltage Regulator interrupt set to high priority level.
PLIN: LIN Interrupt Priority Control.
This bit sets the priority of the CP0 interrupt.
0: LIN interrupt set to low priority level.
1: LIN interrupt set to high priority level.
PCPR: Comparator Rising Edge Interrupt Priority Control.
This bit sets the priority of the Rising Edge Comparator interrupt.
0: Comparator interrupt set to low priority level.
1: Comparator interrupt set to high priority level.
PCPF: Comparator falling Edge Interrupt Priority Control.
This bit sets the priority of the Falling Edge Comparator interrupt.
0: Comparator interrupt set to low priority level.
1: Comparator interrupt set to high priority level.
PPAC0: Programmable Counter Array (PCA0) Interrupt Priority Control.
This bit sets the priority of the PCA0 interrupt.
0: PCA0 interrupt set to low priority level.
1: PCA0 interrupt set to high priority level.
PREG0: ADC0 Conversion Complete Interrupt Priority Control.
This bit sets the priority of the ADC0 Conversion Complete interrupt.
0: ADC0 Conversion Complete interrupt set to low priority level.
1: ADC0 Conversion Complete interrupt set to high priority level.
PWADC0: ADC0 Window Comparison Interrupt Priority Control.
This bit sets the priority of the ADC0 Window Comparison interrupt.
0: ADC0 Window Comparison interrupt set to low priority level.
1: ADC0 Window Comparison interrupt set to high priority level.
Rev. 0.3
C8051F52x-53x
11.5. External Interrupts
The /INT0 and /INT1 external interrupt sources are configurable as active high or low, edge or level sensitive. The IN0PL (/INT0 Polarity) and IN1PL (/INT1 Polarity) bits in the IT01CF register select active high or
active low; the IT0 and IT1 bits in TCON (Section “19.1. Timer 0 and Timer 1” on page 185) select level or
edge sensitive. The table below lists the possible configurations.
IT0
1
1
0
0
IN0PL
0
1
0
1
/INT0 Interrupt
Active low, edge sensitive
Active high, edge sensitive
Active low, level sensitive
Active high, level sensitive
IT1
1
1
0
0
IN1PL
0
1
0
1
/INT1 Interrupt
Active low, edge sensitive
Active high, edge sensitive
Active low, level sensitive
Active high, level sensitive
/INT0 and /INT1 are assigned to Port pins as defined in the IT01CF register (see SFR Definition 11.5).
Note that /INT0 and /INT0 Port pin assignments are independent of any Crossbar assignments. /INT0 and
/INT1 will monitor their assigned Port pins without disturbing the peripheral that was assigned the Port pin
via the Crossbar. To assign a Port pin only to /INT0 and/or /INT1, configure the Crossbar to skip the
selected pin(s). This is accomplished by setting the associated bit in register XBR0 (see Section
“14.1. Priority Crossbar Decoder” on page 119 for complete details on configuring the Crossbar).
IE0 (TCON.1) and IE1 (TCON.3) serve as the interrupt-pending flags for the /INT0 and /INT1 external
interrupts, respectively. If an /INT0 or /INT1 external interrupt is configured as edge-sensitive, the corresponding interrupt-pending flag is automatically cleared by the hardware when the CPU vectors to the ISR.
When configured as level sensitive, the interrupt-pending flag remains logic 1 while the input is active as
defined by the corresponding polarity bit (IN0PL or IN1PL); the flag remains logic 0 while the input is inactive. The external interrupt source must hold the input active until the interrupt request is recognized. It
must then deactivate the interrupt request before execution of the ISR completes or another interrupt
request will be generated.
Rev. 0.3
97
C8051F52x-53x
SFR Definition 11.5. IT01CF: INT0/INT1 Configuration
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
IN1PL
IN1SL2
IN1SL1
IN1SL0
IN0PL
IN0SL2
IN0SL1
IN0SL0
00000001
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xE4
Note: Refer to SFR Definition 19.1. “TCON: Timer Control” on page 189 for INT0/1 edge- or level-sensitive interrupt selection.
IN1PL: /INT1 Polarity
0: /INT1 input is active low.
1: /INT1 input is active high.
Bits 6–4: IN1SL2–0: /INT1 Port Pin Selection Bits
These bits select which Port pin is assigned to /INT1. Note that this pin assignment is independent of the Crossbar; /INT1 will monitor the assigned Port pin without disturbing the
peripheral that has been assigned the Port pin via the Crossbar. The Crossbar will not
assign the Port pin to a peripheral if it is configured to skip the selected pin (accomplished by
setting to ‘1’ the corresponding bit in register P0SKIP).
Bit 7:
IN1SL2-0
000
001
010
011
100
101
110
111
/INT1 Port Pin
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6*
P0.7*
*Note: Available in the C80151F53x parts.
Bit 3:
IN0PL: /INT0 Polarity
0: /INT0 interrupt is active low.
1: /INT0 interrupt is active high.
Bits 2–0: INT0SL2–0: /INT0 Port Pin Selection Bits
These bits select which Port pin is assigned to /INT0. Note that this pin assignment is independent of the Crossbar. /INT0 will monitor the assigned Port pin without disturbing the
peripheral that has been assigned the Port pin via the Crossbar. The Crossbar will not
assign the Port pin to a peripheral if it is configured to skip the selected pin (accomplished by
setting to ‘1’ the corresponding bit in register P0SKIP).
IN0SL2-0
000
001
010
011
100
101
110
111
/INT0 Port Pin
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6*
P0.7*
*Note: Available in the C80151F53x parts.
98
Rev. 0.3
C8051F52x-53x
12. Reset Sources
Reset circuitry allows the controller to be easily placed in a predefined default condition. On entry to this
reset state, the following occur:
•
•
•
•
CIP-51 halts program execution
Special Function Registers (SFRs) are initialized to their defined reset values
External Port pins are forced to a known state
Interrupts and timers are disabled.
All SFRs are reset to the predefined values noted in the SFR detailed descriptions. The contents of internal
data memory are unaffected during a reset; any previously stored data is preserved. However, since the
stack pointer SFR is reset, the stack is effectively lost, even though the data on the stack is not altered.
The Port I/O latches are reset to 0xFF (all logic ones) in open-drain mode. Weak pullups are enabled during and after the reset. For VDD Monitor and power-on resets, the RST pin is driven low until the device
exits the reset state.
On exit from the reset state, the program counter (PC) is reset, and the system clock defaults to the internal oscillator. Refer to Section “15. Oscillators” on page 133 for information on selecting and configuring
the system clock source. The Watchdog Timer is enabled with the system clock divided by 12 as its clock
source (Section “20.3. Watchdog Timer Mode” on page 207 details the use of the Watchdog Timer). Program execution begins at location 0x0000.
VDD
+
-
+
-
C0RSEF
Missing
Clock
Detector
(oneshot)
EN
'0'
Enable
(wired-OR)
/RST
Reset
Funnel
PCA
WDT
(Software Reset)
SWRSF
EN
System
Clock
Illegal Flash
Operation
WDT
Enable
Px.x
Comparator 0
MCD
Enable
Px.x
Power On
Reset
Supply
Monitor
CIP-51
Microcontroller
Core
System Reset
Extended Interrupt
Handler
Figure 12.1. Reset Sources
Rev. 0.3
99
C8051F52x-53x
12.1. Power-On Reset
During power-up, the device is held in a reset state and the RST pin is driven low until VDD settles above
VRST. An additional delay occurs before the device is released from reset; the delay decreases as the VDD
ramp time increases (VDD ramp time is defined as how fast VDD ramps from 0 V to VRST). Figure 12.2 plots
the power-on and VDD monitor reset timing. For valid ramp times (less than 1 ms), the power-on reset
delay (TPORDelay) is typically less than 0.3 ms.
Note: The maximum VDD ramp time is 1 ms; slower ramp times may cause the device to be released from
reset before VDD reaches the VRST level.
volts
On exit from a power-on reset, the PORSF flag (RSTSRC.1) is set by hardware to logic 1. When PORSF is
set, all of the other reset flags in the RSTSRC Register are indeterminate (PORSF is cleared by all other
resets). Since all resets cause program execution to begin at the same location (0x0000), software can
read the PORSF flag to determine if a power-up was the cause of reset. The contents of internal data
memory should be assumed to be undefined after a power-on reset. The VDD monitor is enabled following
a power-on reset.
VDD
VD
D
V RS T
1.0
t
Logic H IG H
Logic LO W
/ RST
T P O R D elay
VDD
M onitor
R eset
P ow er-O n
R eset
Figure 12.2. Power-On and VDD Monitor Reset Timing
100
Rev. 0.3
C8051F52x-53x
12.2. Power-Fail Reset / VDD Monitor
When a power-down transition or power irregularity causes VDD to drop below VRST, the power supply
monitor will drive the RST pin low and hold the CIP-51 in a reset state (see Figure 12.2). When VDD returns
to a level above VRST, the CIP-51 will be released from the reset state. Note that even though internal data
memory contents are not altered by the power-fail reset, it is impossible to determine if VDD dropped below
the level required for data retention. If the PORSF flag reads ‘1’, the data may no longer be valid. The VDD
monitor is enabled and is not selected as a reset source after power-on resets; however its defined state
(enabled/disabled) is not altered by any other reset source. For example, if the VDD monitor is disabled by
software, and a software reset is performed, the VDD monitor will still be disabled after the reset. To protect the integrity of Flash contents, the VDD monitor must be enabled to the higher setting
(VDMLVL = '1') and selected as a reset source if software contains routines which erase or write
Flash memory. If the VDD monitor is not enabled, any erase or write performed on Flash memory
will cause a Flash Error device reset.
The VDD monitor must be enabled before it is selected as a reset source. Selecting the VDD monitor
as a reset source before it is enabled and stabilized may cause a system reset. The procedure for reenabling the VDD monitor and configuring the VDD monitor as a reset source is shown below:
Step 1. Enable the VDD monitor (VDMEN bit in VDM0CN = ‘1’).
Step 2. Wait for the VDD monitor to stabilize (see Table 12.1 for the VDD Monitor turn-on time).
Note: This delay should be omitted if software contains routines which erase or
write Flash memory.
Step 3. Select the VDD monitor as a reset source (PORSF bit in RSTSRC = ‘1’).
See Figure 12.2 for VDD monitor timing; note that the reset delay is not incurred after a VDD monitor reset.
See Table 12.1 for complete electrical characteristics of the VDD monitor.
Note: Software should take care not to inadvertently disable the VDD Monitor as a reset source
when writing to RSTSRC to enable other reset sources or to trigger a software reset. All writes to
RSTSRC should explicitly set PORSF to '1' to keep the VDD Monitor enabled as a reset source.
Rev. 0.3
101
C8051F52x-53x
SFR Definition 12.1. VDDMON: VDD Monitor Control
R/W
R
R/W
R
R
R
R
R
Reset Value
VDDMON VDDSTAT VDMLVL Reserved Reserved Reserved Reserved Reserved 1v000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xFF
Bit7:
VDDMON: VDD Monitor Enable.
This bit turns the VDD monitor circuit on/off. The VDD Monitor cannot generate system resets
until it is also selected as a reset source in register RSTSRC (SFR Definition 12.2). The VDD
Monitor can be allowed to stabilize before it is selected as a reset source. Selecting the
VDD monitor as a reset source before it has stabilized may generate a system reset.
See Table 12.1 for the minimum VDD Monitor turn-on time.
0: VDD Monitor Disabled.
1: VDD Monitor Enabled (default).
Bit6:
VDDSTAT: VDD Status.
This bit indicates the current power supply status (VDD Monitor output).
0: VDD is at or below the VDD Monitor Threshold.
1: VDD is above the VDD Monitor Threshold.
Bit5:
VDMLVL: VDD Level Select.
0: VDD Monitor Threshold is set to VRST-LOW (default).
1: VDD Monitor Threshold is set to VRST-HIGH. This setting is required for any system that
includes code that writes to and/or erases Flash.
Bits4–0: RESERVED. Read = Variable. Write = don’t care.
12.3. External Reset
The external RST pin provides a means for external circuitry to force the device into a reset state. Asserting an active-low signal on the RST pin generates a reset; an external pullup and/or decoupling of the RST
pin may be necessary to avoid erroneous noise-induced resets. See Table 12.1 for complete RST pin
specifications. The PINRSF flag (RSTSRC.0) is set on exit from an external reset.
12.4. Missing Clock Detector Reset
The Missing Clock Detector (MCD) is a one-shot circuit that is triggered by the system clock. If the system
clock remains high or low for more than 100 µs, the one-shot will time out and generate a reset. After a
MCD reset, the MCDRSF flag (RSTSRC.2) will read ‘1’, signifying the MCD as the reset source; otherwise,
this bit reads ‘0’. Writing a ‘1’ to the MCDRSF bit enables the Missing Clock Detector; writing a ‘0’ disables
it. The state of the RST pin is unaffected by this reset.
12.5. Comparator Reset
Comparator0 can be configured as a reset source by writing a ‘1’ to the C0RSEF flag (RSTSRC.5).
Comparator0 should be enabled and allowed to settle prior to writing to C0RSEF to prevent any turn-on
chatter on the output from generating an unwanted reset. The Comparator0 reset is active-low: if the non-
102
Rev. 0.3
C8051F52x-53x
inverting input voltage (on CP0+) is less than the inverting input voltage (on CP0-), the device is put into
the reset state. After a Comparator0 reset, the C0RSEF flag (RSTSRC.5) will read ‘1’ signifying
Comparator0 as the reset source; otherwise, this bit reads ‘0’. The state of the RST pin is unaffected by
this reset.
12.6. PCA Watchdog Timer Reset
The programmable Watchdog Timer (WDT) function of the Programmable Counter Array (PCA) can be
used to prevent software from running out of control during a system malfunction. The PCA WDT function
can be enabled or disabled by software as described in Section “20.3. Watchdog Timer Mode” on
page 207; the WDT is enabled and clocked by SYSCLK / 12 following any reset. If a system malfunction
prevents user software from updating the WDT, a reset is generated and the WDTRSF bit (RSTSRC.5) is
set to ‘1’. The state of the RST pin is unaffected by this reset.
12.7. Flash Error Reset
If a Flash read/write/erase or program read targets an illegal address, a system reset is generated. This
may occur due to any of the following:
•
•
•
•
•
A Flash write or erase is attempted above user code space. This occurs when PSWE is set to ‘1’ and a
MOVX write operation targets an address above the Lock Byte address.
A Flash read is attempted above user code space. This occurs when a MOVC operation targets an
address above the Lock Byte address.
A Program read is attempted above user code space. This occurs when user code attempts to branch
to an address above the Lock Byte address.
A Flash read, write or erase attempt is restricted due to a Flash security setting (see Section
“13.4. Security Options” on page 112).
A Flash write or erase is attempted while the VDD Monitor is disabled.
The FERROR bit (RSTSRC.6) is set following a Flash error reset. The state of the RST pin is unaffected by
this reset.
12.8. Software Reset
Software may force a reset by writing a ‘1’ to the SWRSF bit (RSTSRC.4). The SWRSF bit will read ‘1’ following a software forced reset. The state of the RST pin is unaffected by this reset.
Rev. 0.3
103
C8051F52x-53x
SFR Definition 12.2. RSTSRC: Reset Source
R/W
—
Bit7
R
R/W
FERROR C0RSEF
Bit6
Bit5
R/W
SWRSF
Bit4
R
R/W
WDTRSF MCDRSF
Bit3
Bit2
R/W
R
Reset Value
PORSF
PINRSF
Variable
Bit1
Bit0
SFR Address: 0xEF
Note: Software should avoid read modify write instructions when writing values to RSTSRC.
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
104
UNUSED. Read = 1, Write = don't care.
FERROR: Flash Error Indicator.
0: Source of last reset was not a Flash read/write/erase error.
1: Source of last reset was a Flash read/write/erase error.
C0RSEF: Comparator0 Reset Enable and Flag.
0: Read: Source of last reset was not Comparator0.
Write: Comparator0 is not a reset source.
1: Read: Source of last reset was Comparator0.
Write: Comparator0 is a reset source (active-low).
SWRSF: Software Reset Force and Flag.
0: Read: Source of last reset was not a write to the SWRSF bit.
Write: No Effect.
1: Read: Source of last was a write to the SWRSF bit.
Write: Forces a system reset.
WDTRSF: Watchdog Timer Reset Flag.
0: Source of last reset was not a WDT timeout.
1: Source of last reset was a WDT timeout.
MCDRSF: Missing Clock Detector Flag.
0: Read: Source of last reset was not a Missing Clock Detector timeout.
Write: Missing Clock Detector disabled.
1: Read: Source of last reset was a Missing Clock Detector timeout.
Write: Missing Clock Detector enabled; triggers a reset if a missing clock condition is
detected.
PORSF: Power-On Reset Force and Flag.
This bit is set anytime a power-on reset occurs. Writing this bit enables/disables the VDD
monitor as a reset source. Note: writing ‘1’ to this bit before the VDD monitor is enabled
and stabilized may cause a system reset. See register VDDMON (SFR Definition 12.1)
0: Read: Last reset was not a power-on or VDD monitor reset.
Write: VDD monitor is not a reset source.
1: Read: Last reset was a power-on or VDD monitor reset; all other reset flags indeterminate.
Write: VDD monitor is a reset source.
PINRSF: HW Pin Reset Flag.
0: Source of last reset was not RST pin.
1: Source of last reset was RST pin.
Rev. 0.3
C8051F52x-53x
Table 12.1. Reset Electrical Characteristics
–40 to +125 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
IOL = 8.5 mA, VDD = 2.1 V
—
—
0.8
V
RST Input High Voltage
0.7 x
VDD
—
—
V
RST Input Low Voltage
—
—
0.3 x
VDD
V
—
14
TBD
µA
VDD Monitor Threshold (VRST-LOW)
TBD
1.7
TBD
V
VDD Monitor Threshold (VRST-HIGH)
TBD
2.2
TBD
V
RST Output Low Voltage
RST Input Pullup Current
RST = 0.0 V
Missing Clock Detector Timeout
Time from last system
clock rising edge to reset
initiation
TBD
350
650
µs
Reset Time Delay
Delay between release of
any reset source and
code execution at location
0x0000
TBD
—
—
µs
Minimum RST Low Time to Generate a
System Reset
TBD
—
—
µs
VDD Monitor Turn-on Time
TBD
—
—
µs
—
23
TBD
µA
VDD Monitor Supply Current
VDD = 2.1 V
Rev. 0.3
105
C8051F52x-53x
NOTES:
106
Rev. 0.3
C8051F52x-53x
13. Flash Memory
On-chip, re-programmable Flash memory is included for program code and non-volatile data storage. The
Flash memory can be programmed in-system through the C2 interface or by software using the MOVX
write instruction. Once cleared to logic 0, a Flash bit must be erased to set it back to logic 1. Flash bytes
would typically be erased (set to 0xFF) before being reprogrammed. The write and erase operations are
automatically timed by hardware for proper execution; data polling to determine the end of the write/erase
operations is not required. Code execution is stalled during Flash write/erase operations. Refer to
Table 13.2 for complete Flash memory electrical characteristics.
13.1. Programming The Flash Memory
The simplest means of programming the Flash memory is through the C2 interface using programming
tools provided by Silicon Laboratories or a third party vendor. This is the only means for programming a
non-initialized device. For details on the C2 commands to program Flash memory, see Section “22. C2
Interface” on page 217.
To protect the integrity of Flash contents, the VDD monitor must be enabled to the higher setting
(VDMLVL = '1') and selected as a reset source if software contains routines which erase or write
Flash memory. If the VDD monitor is not enabled, any erase or write performed on Flash memory
will cause a Flash Error device reset.
The VDD monitor must be enabled before it is selected as a reset source. Selecting the VDD monitor
as a reset source before it is enabled and stabilized may cause a system reset. The procedure for reenabling the VDD monitor and configuring the VDD monitor as a reset source is shown below:
Step 1. Enable the VDD monitor (VDMEN bit in VDM0CN = ‘1’).
Step 2. Wait for the VDD monitor to stabilize (see Table 12.1 for the VDD Monitor turn-on time).
Note: This delay should be omitted if software contains routines which erase or
write Flash memory.
Step 3. Select the VDD monitor as a reset source (PORSF bit in RSTSRC = ‘1’).
13.1.1. Flash Lock and Key Functions
Flash writes and erases by user software are protected with a lock and key function. The Flash Lock and
Key Register (FLKEY) must be written with the correct key codes, in sequence, before Flash operations
may be performed. The key codes are: 0xA5, 0xF1. The timing does not matter, but the codes must be
written in order. If the key codes are written out of order, or the wrong codes are written, Flash writes and
erases will be disabled until the next system reset. Flash writes and erases will also be disabled if a Flash
write or erase is attempted before the key codes have been written properly. The Flash lock resets after
each write or erase; the key codes must be written again before a following Flash operation can be performed. The FLKEY register is detailed in SFR Definition 13.2.
Rev. 0.3
107
C8051F52x-53x
13.1.2. Flash Erase Procedure
The Flash memory can be programmed by software using the MOVX write instruction with the address and
data byte to be programmed provided as normal operands. Before writing to Flash memory using MOVX,
Flash write operations must be enabled by: (1) setting the PSWE Program Store Write Enable bit
(PSCTL.0) to logic 1 (this directs the MOVX writes to target Flash memory); and (2) Writing the Flash key
codes in sequence to the Flash Lock register (FLKEY). The PSWE bit remains set until cleared by software.
A write to Flash memory can clear bits to logic 0 but cannot set them; only an erase operation can set bits
to logic 1 in Flash. A byte location to be programmed should be erased before a new value is written.
The Flash memory is organized in 512-byte pages. The erase operation applies to an entire page (setting
all bytes in the page to 0xFF). To erase an entire 512-byte page, perform the following steps:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Disable interrupts (recommended).
Write the first key code to FLKEY: 0xA5.
Write the second key code to FLKEY: 0xF1.
Set the PSEE bit (register PSCTL).
Set the PSWE bit (register PSCTL).
Using the MOVX instruction, write a data byte to any location within the 512-byte page to
be erased.
Step 7. Clear the PSWE and PSEE bits.
Step 8. Re-enable interrupts.
13.1.3. Flash Write Procedure
The recommended procedure for writing Flash in single bytes is:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Disable interrupts.
Write the first key code to FLKEY: 0xA5.
Write the second key code to FLKEY: 0xF1.
Set the PSWE bit (register PSCTL).
Clear the PSEE bit (register PSCTL).
Using the MOVX instruction, write a single data byte to the desired location within the 512byte sector.
Step 7. Clear the PSWE bit.
Step 8. Re-enable interrupts.
Steps 2–7 must be repeated for each byte to be written.
108
Rev. 0.3
C8051F52x-53x
For block Flash writes, the Flash write procedure is only performed after the last byte of each block is written with the MOVX write instruction. A Flash write block is two bytes long, from even addresses to odd
addresses. Writes must be performed sequentially (i.e. addresses ending in 0b and 1b must be written in
order). The Flash write will be performed following the MOVX write that targets the address ending in 1b. If
a byte in the block does not need to be updated in Flash, it should be written to 0xFF. The recommended
procedure for writing Flash in blocks is:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Disable interrupts.
Write the first key code to FLKEY: 0xA5.
Write the second key code to FLKEY: 0xF1.
Set the PSWE bit (register PSCTL).
Clear the PSEE bit (register PSCTL).
Using the MOVX instruction, write the first data byte to the even block location (ending in
0b).
Step 7. Clear the PSWE bit (register PSCTL).
Step 8. Write the first key code to FLKEY: 0xA5.
Step 9. Write the second key code to FLKEY: 0xF1.
Step 10. Set the PSWE bit (register PSCTL).
Step 11. Clear the PSEE bit (register PSCTL).
Step 12. Using the MOVX instruction, write the second data byte to the odd block location (ending
in 1b).
Step 13. Clear the PSWE bit (register PSCTL).
Step 14. Re-enable interrupts.
Steps 2–13 must be repeated for each block to be written.
13.2. Flash Write and Erase Guidelines
Any system which contains routines which write or erase Flash memory from software involves some risk
that the write or erase routines will execute unintentionally if the CPU is operating outside its specified
operating range of VDD, system clock frequency, or temperature. This accidental execution of Flash modifying code can result in alteration of Flash memory contents causing a system failure that is only recoverable by re-Flashing the code in the device.
The following guidelines are recommended for any system which contains routines which write or erase
Flash from code.
Rev. 0.3
109
C8051F52x-53x
13.2.1. VDD Maintenance and the VDD monitor
1. If the system power supply is subject to voltage or current "spikes," add sufficient transient
protection devices to the power supply to ensure that the supply voltages listed in the Absolute
Maximum Ratings table are not exceeded.
2. Make certain that the minimum VDD rise time specification of 1 ms is met. If the system cannot
meet this rise time specification, then add an external VDD brownout circuit to the RST pin of
the device that holds the device in reset until VDD reaches 2.7 V and re-asserts RST if VDD
drops below 2.7 V.
3. Enable the on-chip VDD monitor and enable the VDD monitor as a reset source as early in code
as possible. This should be the first set of instructions executed after the Reset Vector. For 'C'based systems, this will involve modifying the startup code added by the 'C' compiler. See your
compiler documentation for more details. Make certain that there are no delays in software
between enabling the VDD monitor and enabling the VDD monitor as a reset source. Code
examples showing this can be found in “AN201: Writing to Flash from Firmware", available
from the Silicon Laboratories web site.
4. As an added precaution, explicitly enable the VDD monitor and enable the VDD monitor as a
reset source inside the functions that write and erase Flash memory. The VDD monitor enable
instructions should be placed just after the instruction to set PSWE to a '1', but before the
Flash write or erase operation instruction.
5. Make certain that all writes to the RSTSRC (Reset Sources) register use direct assignment
operators and explicitly DO NOT use the bit-wise operators (such as AND or OR). For example, "RSTSRC = 0x02" is correct. "RSTSRC |= 0x02" is incorrect.
6. Make certain that all writes to the RSTSRC register explicitly set the PORSF bit to a '1'. Areas
to check are initialization code which enables other reset sources, such as the Missing Clock
Detector or Comparator, for example, and instructions which force a Software Reset. A global
search on "RSTSRC" can quickly verify this.
110
Rev. 0.3
C8051F52x-53x
13.2.2. PSWE Maintenance
7. Reduce the number of places in code where the PSWE bit (b0 in PSCTL) is set to a '1'. There
should be exactly one routine in code that sets PSWE to a '1' to write Flash bytes and one routine in code that sets PSWE and PSEE both to a '1' to erase Flash pages.
8. Minimize the number of variable accesses while PSWE is set to a '1'. Handle pointer address
updates and loop variable maintenance outside the "PSWE = 1; ... PSWE = 0;" area. Code
examples showing this can be found in AN201, "Writing to Flash from Firmware", available
from the Silicon Laboratories web site.
9. Disable interrupts prior to setting PSWE to a '1' and leave them disabled until after PSWE has
been reset to '0'. Any interrupts posted during the Flash write or erase operation will be serviced in priority order after the Flash operation has been completed and interrupts have been
re-enabled by software.
10. Make certain that the Flash write and erase pointer variables are not located in XRAM. See
your compiler documentation for instructions regarding how to explicitly locate variables in different memory areas.
11. Add address bounds checking to the routines that write or erase Flash memory to ensure that
a routine called with an illegal address does not result in modification of the Flash.
13.2.3. System Clock
12. If operating from an external crystal, be advised that crystal performance is susceptible to
electrical interference and is sensitive to layout and to changes in temperature. If the system is
operating in an electrically noisy environment, use the internal oscillator or use an external
CMOS clock.
13. If operating from the external oscillator, switch to the internal oscillator during Flash write or
erase operations. The external oscillator can continue to run, and the CPU can switch back to
the external oscillator after the Flash operation has completed.
Additional Flash recommendations and example code can be found in AN201, "Writing to Flash from Firmware", available from the Silicon Laboratories web site.
Rev. 0.3
111
C8051F52x-53x
13.3. Non-volatile Data Storage
The Flash memory can be used for non-volatile data storage as well as program code. This allows data
such as calibration coefficients to be calculated and stored at run time. Data is written using the MOVX
write instruction and read using the MOVC instruction. Note: MOVX read instructions always target XRAM.
13.4. Security Options
The CIP-51 provides security options to protect the Flash memory from inadvertent modification by software as well as to prevent the viewing of proprietary program code and constants. The Program Store
Write Enable (bit PSWE in register PSCTL) and the Program Store Erase Enable (bit PSEE in register
PSCTL) bits protect the Flash memory from accidental modification by software. PSWE must be explicitly
set to ‘1’ before software can modify the Flash memory; both PSWE and PSEE must be set to ‘1’ before
software can erase Flash memory. Additional security features prevent proprietary program code and data
constants from being read or altered across the C2 interface.
A Security Lock Byte located at the last byte of Flash user space offers protection of the Flash program
memory from access (reads, writes, or erases) by unprotected code or the C2 interface. The Flash security
mechanism allows the user to lock n 512-byte Flash pages, starting at page 0 (addresses 0x0000 to
0x01FF), where n is the 1’s complement number represented by the Security Lock Byte. Note that the
page containing the Flash Security Lock Byte is unlocked when no other Flash pages are locked
(all bits of the Lock Byte are ‘1’) and locked when any other Flash pages are locked (any bit of the
Lock Byte is ‘0’). See example below.
Security Lock Byte:
1’s Complement:
Flash pages locked:
11111101b
00000010b
3 (First two Flash pages + Lock Byte Page)
Addresses locked:
0x0000 to 0x03FF (first two Flash pages)
0x1C00 to 0x1DFF in C8051F520/1 and ‘F530/1
0x0C00 to 0x0FFF in C8051F523/4 and ‘F533/4 and
0x0600 to 0x07FF in C8051F526/7 and ‘F536/7
C8051F523/4 and ‘F533/4
C8051F520/1 and ‘F530/1
Reserved
Locked when
any other Flash
pages are
locked
Access limit
set according
to the Flash
security lock
byte
Lock Byte
0x1E00
0x1DFF
C8051F526/7 and ‘F536/7
Reserved
Lock Byte
Reserved
0x0FFF
0x07FF
0x0FFE
0x07FE
0x1C00
0x0E00
0x0600
Flash memory organized
Unlocked
Flash Pages
in 512-byte
pages
Unlocked Flash Pages
Unlocked Flash Pages
0x0000
0x0000
Figure 13.1. Flash Program Memory Map
112
Lock Byte
0x1DFE
Rev. 0.3
0x0000
C8051F52x-53x
The level of Flash security depends on the Flash access method. The three Flash access methods that
can be restricted are reads, writes, and erases from the C2 debug interface, user firmware executing on
unlocked pages, and user firmware executing on locked pages.
Accessing Flash from the C2 debug interface:
1. Any unlocked page may be read, written, or erased.
2. Locked pages cannot be read, written, or erased.
3. The page containing the Lock Byte may be read, written, or erased if it is unlocked.
4. Reading the contents of the Lock Byte is always permitted only if no pages are locked.
5. Locking additional pages (changing ‘1’s to ‘0’s in the Lock Byte) is not permitted.
6. Unlocking Flash pages (changing ‘0’s to ‘1’s in the Lock Byte) requires the C2 Device Erase
command, which erases all Flash pages including the page containing the Lock Byte and the
Lock Byte itself.
7. The Reserved Area cannot be read, written, or erased.
Accessing Flash from user firmware executing from an unlocked page:
1. Any unlocked page except the page containing the Lock Byte may be read, written, or erased.
2. Locked pages cannot be read, written, or erased. An erase attempt on the page containing the
Lock Byte will result in a Flash Error device reset.
3. The page containing the Lock Byte cannot be erased. It may be read or written only if it is
unlocked. An erase attempt on the page containing the Lock Byte will result in a Flash Error
device reset.
4. Reading the contents of the Lock Byte is always permitted.
5. Locking additional pages (changing ‘1’s to ‘0’s in the Lock Byte) is not permitted.
6. Unlocking Flash pages (changing ‘0’s to ‘1’s in the Lock Byte) is not permitted.
7. The Reserved Area cannot be read, written, or erased. Any attempt to access the reserved
area, or any other locked page, will result in a Flash Error device reset.
Accessing Flash from user firmware executing from a locked page:
1. Any unlocked page except the page containing the Lock Byte may be read, written, or erased.
2. Any locked page except the page containing the Lock Byte may be read, written, or erased. An
erase attempt on the page containing the Lock Byte will result in a Flash Error device reset.
3. The page containing the Lock Byte cannot be erased. It may only be read or written. An
erase attempt on the page containing the Lock Byte will result in a Flash Error device reset.
4. Reading the contents of the Lock Byte is always permitted.
5. Locking additional pages (changing ‘1’s to ‘0’s in the Lock Byte) is not permitted.
6. Unlocking Flash pages (changing ‘0’s to ‘1’s in the Lock Byte) is not permitted.
7. The Reserved Area cannot be read, written, or erased. Any attempt to access the reserved
area, or any other locked page, will result in a Flash Error device reset.
Rev. 0.3
113
C8051F52x-53x
The level of Flash security depends on the Flash access method. The three Flash access methods that
can be restricted are reads, writes, and erases from the C2 debug interface, user firmware executing on
unlocked pages, and user firmware executing on locked pages. Table 13.1 summarizes the Flash security
features of the 'F52x/F53x devices.
Table 13.1. Flash Security Summary
Action
C2 Debug
Interface
User Firmware executing from:
an unlocked page
a locked page
Permitted
Permitted
Permitted
Not Permitted
Flash Error Reset
Permitted
Read or Write page containing Lock Byte
(if no pages are locked)
Permitted
Permitted
Permitted
Read or Write page containing Lock Byte
(if any page is locked)
Not Permitted
Flash Error Reset
Permitted
Read contents of Lock Byte
(if no pages are locked)
Permitted
Permitted
Permitted
Read contents of Lock Byte
(if any page is locked)
Not Permitted
Flash Error Reset
Permitted
Read, Write or Erase unlocked pages
(except page with Lock Byte)
Read, Write or Erase locked pages
(except page with Lock Byte)
Erase page containing Lock Byte
(if no pages are locked)
Permitted
Flash Error Reset Flash Error Reset
C2 Device
Erase Only
Flash Error Reset Flash Error Reset
Lock additional pages
(change '1's to '0's in the Lock Byte)
Not Permitted
Flash Error Reset Flash Error Reset
Unlock individual pages
(change '0's to '1's in the Lock Byte)
Not Permitted
Flash Error Reset Flash Error Reset
Read, Write or Erase Reserved Area
Not Permitted
Flash Error Reset Flash Error Reset
Erase page containing Lock Byte - Unlock all
pages (if any page is locked)
C2 Device Erase - Erases all Flash pages including the page containing the Lock Byte.
Flash Error Reset - Not permitted; Causes Flash Error Device Reset (FERROR bit in RSTSRC is '1' after
reset).
- All prohibited operations that are performed via the C2 interface are ignored (do not cause device reset).
- Locking any Flash page also locks the page containing the Lock Byte.
- Once written to, the Lock Byte cannot be modified except by performing a C2 Device Erase.
- If user code writes to the Lock Byte, the Lock does not take effect until the next device reset.
114
Rev. 0.3
C8051F52x-53x
SFR Definition 13.1. PSCTL: Program Store R/W Control
R
R
R
R
R
R
R/W
R/W
Reset Value
-
-
-
-
-
-
PSEE
PSWE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x8F
Bits7–2: UNUSED: Read = 000000b, Write = don’t care.
Bit1:
PSEE: Program Store Erase Enable
Setting this bit (in combination with PSWE) allows an entire page of Flash program memory
to be erased. If this bit is logic 1 and Flash writes are enabled (PSWE is logic 1), a write to
Flash memory using the MOVX instruction will erase the entire page that contains the location addressed by the MOVX instruction. The value of the data byte written does not matter.
0: Flash program memory erasure disabled.
1: Flash program memory erasure enabled.
Bit0:
PSWE: Program Store Write Enable
Setting this bit allows writing a byte of data to the Flash program memory using the MOVX
write instruction. The Flash location should be erased before writing data.
0: Writes to Flash program memory disabled.
1: Writes to Flash program memory enabled; the MOVX write instruction targets Flash
memory.
SFR Definition 13.2. FLKEY: Flash Lock and Key
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xB7
Bits7–0: FLKEY: Flash Lock and Key Register
Write:
This register provides a lock and key function for Flash erasures and writes. Flash writes
and erases are enabled by writing 0xA5 followed by 0xF1 to the FLKEY register. Flash
writes and erases are automatically disabled after the next write or erase is complete. If any
writes to FLKEY are performed incorrectly, or if a Flash write or erase operation is attempted
while these operations are disabled, the Flash will be permanently locked from writes or erasures until the next device reset. If an application never writes to Flash, it can intentionally
lock the Flash by writing a non-0xA5 value to FLKEY from software.
Read:
When read, bits 1–0 indicate the current Flash lock state.
00: Flash is write/erase locked.
01: The first key code has been written (0xA5).
10: Flash is unlocked (writes/erases allowed).
11: Flash writes/erases disabled until the next reset.
Rev. 0.3
115
C8051F52x-53x
Table 13.2. Flash Electrical Characteristics
VDD = 1.8 to 2.75 V; –40 to +125 ºC unless otherwise specified
Parameter
Conditions
Min
C8051F520/1 and ‘F530/1
7680
Flash Size
C8051F523/4 and ‘F533/4
4096
C8051F526/7 and ‘F536/7
2048
Endurance
VDD is 2.25 V or greater
40 k
Typ
Max
Units
—
—
bytes
150 k
—
Erase/Write
Erase Cycle Time
32
40
48
ms
Write Cycle Time
76
92
114
µs
2.25
—
—
V
VDD
116
Write/Erase Operations
Rev. 0.3
C8051F52x-53x
14. Port Input/Output
Digital and analog resources are available through up to 16 I/O pins. Port pins are organized as two or one
byte-wide Ports. Each of the Port pins can be defined as general-purpose I/O (GPIO) or analog input/output; Port pins P0.0 - P1.7 can be assigned to one of the internal digital resources as shown in Figure 14.3.
The designer has complete control over which functions are assigned, limited only by the number of physical I/O pins. This resource assignment flexibility is achieved through the use of a Priority Crossbar
Decoder. Note that the state of a Port I/O pin can always be read in the corresponding Port latch, regardless of the Crossbar settings.
The Crossbar assigns the selected internal digital resources to the I/O pins based on the peripheral priority
order of the Priority Decoder (Figure 14.3 and Figure 14.4). The registers XBR0 and XBR1, defined in SFR
Definition 14.1 and SFR Definition 14.2, are used to select internal digital functions.
Port I/Os on P0 are 5.25 V tolerant over the operating range of VREGIN. Figure 14.2 shows the Port cell circuit. The Port I/O cells are configured as either push-pull or open-drain in the Port Output Mode registers
(PnMDOUT, where n = 0,1). Complete Electrical Specifications for Port I/O are given in Table 14.1 on
page 132.
P0MASK, P0MATCH
P1MASK, P1MATCH
Registers
XBR0, XBR1,
PnSKIP Registers
Priority
Decoder
Highest
Priority
2
UART
4
(Internal Digital Signals)
SPI
8
2
LIN
CP0
Outputs
8
P0.7
P1
I/O
Cells
P1.0
P1.7
2
P1.0–1.7 and P0.7
available on C8051F53x
parts
8
P0
P0.0
2
7
T0, T1
P0
I/O
Cells
Digital
Crossbar
SYSCLK
PCA
(Port Latches)
Lowest
Priority
PnMDOUT,
PnMDIN Registers
(P0.0-P0.7)
8
P1
(P1.0-P1.7*)
Figure 14.1. Port I/O Functional Block Diagram
Rev. 0.3
117
C8051F52x-53x
/WEAK-PULLUP
VIO
PUSH-PULL
/PORT-OUTENABLE
(WEAK)
PORT
PAD
PORT-OUTPUT
GND
Analog Select
ANALOG INPUT
PORT-INPUT
Figure 14.2. Port I/O Cell Block Diagram
118
VIO
Rev. 0.3
C8051F52x-53x
14.1. Priority Crossbar Decoder
The Priority Crossbar Decoder (Figure 14.3) assigns a priority to each I/O function, starting at the top with
UART0. When a digital resource is selected, the least-significant unassigned Port pin is assigned to that
resource (excluding UART0, which will be assigned to pins P0.4 and P0.5). If a Port pin is assigned, the
Crossbar skips that pin when assigning the next selected resource. Additionally, the Crossbar will skip Port
pins whose associated bits in the PnSKIP registers are set. The PnSKIP registers allow software to skip
Port pins that are to be used for analog input, dedicated functions, or GPIO.
Important Note on Crossbar Configuration: If a Port pin is claimed by a peripheral without use of the
Crossbar, its corresponding PnSKIP bit should be set. This applies to P1.0 and/or P0.7 (‘F530) or P0.2
and/or P0.3 (‘F5250) for the external oscillator, P0.0 for VREF, P1.2 (‘F530) or P0.5 (‘F530) for the external
CNVSTR signal, and any selected ADC or comparator inputs. The Crossbar skips selected pins as if they
were already assigned, and moves to the next unassigned pin. Figure 14.3 shows the Crossbar Decoder
priority with no Port pins skipped (P0SKIP, P1SKIP); Figure 14.4 shows the Crossbar Decoder priority with
the XTAL1 (P1.0) and XTAL2 (P1.1) pins skipped (P1SKIP = 0x03).
P1
XTAL2
0
1
2
5*
6
7
0
1
2
5
6
7
0
0
0
0
0
0
P 0S K I P [0:7]
0
0
0
0
0
0
0
0
P 1S K IP [0:7]
0
0
VREF
T S S O P 20 a n d Q F N 2 0
P IN I/O
XTAL1
S F S i g n a ls
CNVSTR
P0
3
4*
3
4
TX 0
RX 0
S CK
M IS O
MOSI
N S S **
L IN -T X
L IN _R X
CP 0
C P 0A
/S YS C L K
C EX 0
C EX 1
C EX 2
EC I
T0
T1
*Note: Refer to Section “21. Revision Specific Behavior” on page 215.
**Note: 4-Wire SPI Only.
Figure 14.3. Crossbar Priority Decoder with No Pins Skipped
(TSSOP 20 and QFN 20)
Rev. 0.3
119
C8051F52x-53x
P0
XTAL1
XTAL2
PIN I/O
0
1
2
4* 5*
6
7
0
1
6
7
0
0
0 0 0 0
P0S KIP[0:7]
0
1
1
0 0 0 0 0 0
P1S KIP [0:7] = 0x 03
0
VREF
TSS OP 20 a nd QFN 20
CNVSTR
P1
SF S igna ls
3
2
3
4
5
TX0
RX 0
SCK
M ISO
M OS I
NS S**
LIN-TX
LIN-RX
CP 0
CP 0A
/SYS CLK
CEX 0
CEX 1
CEX 2
ECI
T0
T1
Port pin potentially assignable to peripheral
SF S igna ls
Special Function Signals are not assigned by the crossbar.
W hen these signals are enabled, the CrossB ar m ust be m anually configured
to skip their corresponding port pins.
*Note: Refer to Section “21. Revision Specific Behavior” on page 215.
**Note: 4-Wire SPI Only.
Figure 14.4. Crossbar Priority Decoder with Crystal Pins Skipped
(TSSOP 20 and QFN 20)
120
Rev. 0.3
C8051F52x-53x
PIN I/O
2
0
1
0
0 0 0 0
P0SKIP[0:5]
CNVSTR
XTAL2
VREF
SF Signals QFN10
XTAL1
P0
3 4* 5*
TX0
RX0
SCK
MISO
MOSI
NSS**
LIN-TX
LIN_RX
CP0
CP0A
/SYSCLK
CEX0
CEX1
CEX2
ECI
T0
T1
0
*Note: Refer to Section “21. Revision Specific Behavior” on page 215.
**Note: 4-Wire SPI Only.
Figure 14.5. Crossbar Priority Decoder with No Pins Skipped (QFN 10)
Rev. 0.3
121
C8051F52x-53x
PIN I/O
2
0
1
0
0 1 1 0
P0SKIP[0:5]
CNVSTR
XTAL2
VREF
SF Signals QFN 10
XTAL1
P0
3 4* 5*
TX0
RX0
SCK
MISO
MOSI
NSS**
LIN-TX
LIN-RX
CP0
CP0A
/SYSCLK
CEX0
CEX1
CEX2
ECI
T0
T1
0
Port pin potentially assignable to peripheral
SF Signals
Special Function Signals are not assigned by the crossbar.
When these signals are enabled, the CrossBar must be manually configured
to skip their corresponding port pins.
*Note: Refer to Section “21. Revision Specific Behavior” on page 215.
**Note: 4-Wire SPI Only.
Figure 14.6. Crossbar Priority Decoder with Crystal Pins Skipped (QFN 10)
Registers XBR0 and XBR1 are used to assign the digital I/O resources to the physical I/O Port pins. Note
that when the SMBus is selected, the Crossbar assigns both pins associated with the SMBus (SDA and
SCL); when the UART is selected, the Crossbar assigns both pins associated with the UART (TX and RX).
UART0 pin assignments are fixed for bootloading purposes: UART TX0 is always assigned to P0.3 or
P0.4*; UART RX0 is always assigned to P0.4 or P0.5*. Standard Port I/Os appear contiguously starting at
P0.0 after prioritized functions and skipped pins are assigned.
*Note: Refer to Section “21. Revision Specific Behavior” on page 215.
122
Rev. 0.3
C8051F52x-53x
Important Note: The SPI can be operated in either 3-wire or 4-wire modes, depending on the state of the
NSSMD1–NSSMD0 bits in register SPI0CN. According to the SPI mode, the NSS signal may or may not
be routed to a Port pin.
14.2. Port I/O Initialization
Port I/O initialization consists of the following steps:
Step 1. Select the input mode (analog or digital) for all Port pins, using the Port Input Mode
register (PnMDIN).
Step 2. Select the output mode (open-drain or push-pull) for all Port pins, using the Port Output
Mode register (PnMDOUT).
Step 3. Select any pins to be skipped by the I/O Crossbar using the Port Skip registers (PnSKIP).
Step 4. Assign Port pins to desired peripherals using the XBRn registers.
Step 5. Enable the Crossbar (XBARE = ‘1’).
All Port pins must be configured as either analog or digital inputs. Any pins to be used as Comparator or
ADC inputs should be configured as an analog inputs. When a pin is configured as an analog input, its
weak pullup, digital driver, and digital receiver are disabled. This process saves power and reduces noise
on the analog input. Pins configured as digital inputs may still be used by analog peripherals; however, this
practice is not recommended.
Additionally, all analog input pins should be configured to be skipped by the Crossbar (accomplished by
setting the associated bits in PnSKIP). Port input mode is set in the PnMDIN register, where a ‘1’ indicates
a digital input, and a ‘0’ indicates an analog input. All pins default to digital inputs on reset. See SFR Definition 14.4 for the PnMDIN register details.
Important Note: Port 0 and Port 1 pins are 5.25 V tolerant across the operating range of VREGIN.
The output driver characteristics of the I/O pins are defined using the Port Output Mode registers (PnMDOUT). Each Port Output driver can be configured as either open drain or push-pull. This selection is
required even for the digital resources selected in the XBRn registers, and is not automatic. When the
WEAKPUD bit in XBR1 is ‘0’, a weak pullup is enabled for all Port I/O configured as open-drain. WEAKPUD does not affect the push-pull Port I/O. Furthermore, the weak pullup is turned off on an output that is
driving a ‘0’ and for pins configured for analog input mode to avoid unnecessary power dissipation.
Registers XBR0 and XBR1 must be loaded with the appropriate values to select the digital I/O functions
required by the design. Setting the XBARE bit in XBR1 to ‘1’ enables the Crossbar. Until the Crossbar is
enabled, the external pins remain as standard Port I/O (in input mode), regardless of the XBRn Register
settings. For given XBRn Register settings, one can determine the I/O pin-out using the Priority Decode
Table.
The Crossbar must be enabled to use Port pins as standard Port I/O in output mode. Port output drivers
are disabled while the Crossbar is disabled.
Rev. 0.3
123
C8051F52x-53x
SFR Definition 14.1. XBR0: Port I/O Crossbar Register 0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
-
-
CP0AE
CP0E
SYSCKE
LINE
SPI0E
URT0E
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xE1
Bit7–6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
RESERVED. Read = 0b; Must write 0b.
CP0AE: Comparator0 Asynchronous Output Enable
0: Asynchronous CP0 unavailable at Port pin.
1: Asynchronous CP0 routed to Port pin.
CP0E: Comparator0 Output Enable
0: CP0 unavailable at Port pin.
1: CP0 routed to Port pin.
SYSCKE: /SYSCLK Output Enable
0: /SYSCLK unavailable at Port pin.
1: /SYSCLK output routed to Port pin.
LINE. Lin Output Enable
SPI0E: SPI I/O Enable
0: SPI I/O unavailable at Port pins.
1: SPI I/O routed to Port pins. Note that the SPI can be assigned either 3 or 4 GPIO pins.
URT0E: UART I/O Output Enable
0: UART I/O unavailable at Port pin.
1: UART TX0, RX0 routed to Port pins (P0.3 and P0.4) or (P0.4 and P0.5).
Note:Please refer to Section “21. Revision Specific Behavior” on page 215.
124
Rev. 0.3
C8051F52x-53x
SFR Definition 14.2. XBR1: Port I/O Crossbar Register 1
R/W
R/W
WEAKPUD XBARE
Bit7
Bit6
R/W
R/W
R/W
R/W
T1E
T0E
ECIE
—
Bit5
Bit4
Bit3
Bit2
R/W
R/W
PCA0ME
Bit1
Reset Value
00000000
Bit0
SFR Address: 0xE2
Bit7:
WEAKPUD: Port I/O Weak Pullup Disable.
0: Weak Pullups enabled (except for Ports whose I/O are configured as analog input).
1: Weak Pullups disabled.
Bit6:
XBARE: Crossbar Enable.
0: Crossbar disabled.
1: Crossbar enabled.
Bit5:
T1E: T1 Enable
0: T1 unavailable at Port pin.
1: T1 routed to Port pin.
Bit4:
T0E: T0 Enable
0: T0 unavailable at Port pin.
1: T0 routed to Port pin.
Bit3:
ECIE: PCA0 External Counter Input Enable
0: ECI unavailable at Port pin.
1: ECI routed to Port pin.
Bit2:
Reserved.
Bits1–0: PCA0ME: PCA Module I/O Enable Bits.
00: All PCA I/O unavailable at Port pins.
01: CEX0 routed to Port pin.
10: CEX0, CEX1 routed to Port pins.
11: CEX0, CEX1, CEX2 routed to Port pins.
14.3. General Purpose Port I/O
Port pins that remain unassigned by the Crossbar and are not used by analog peripherals can be used for
general purpose I/O. Ports P0–P1 are accessed through corresponding special function registers (SFRs)
that are both byte addressable and bit addressable. When writing to a Port, the value written to the SFR is
latched to maintain the output data value at each pin. When reading, the logic levels of the Port's input pins
are returned regardless of the XBRn settings (i.e., even when the pin is assigned to another signal by the
Crossbar, the Port register can always read its corresponding Port I/O pin). The exception to this is the
execution of the read-modify-write instructions that target a Port Latch register as the destination. The
read-modify-write instructions when operating on a Port SFR are the following: ANL, ORL, XRL, JBC, CPL,
INC, DEC, DJNZ and MOV, CLR or SETB, when the destination is an individual bit in a Port SFR. For
these instructions, the value of the latch register (not the pin) is read, modified, and written back to the
SFR.
Rev. 0.3
125
C8051F52x-53x
In addition to performing general purpose I/O, P0 and P1 can generate a port match event if the logic levels of the Port’s input pins match a software controlled value. A port match event is generated if
(P0 & P0MASK) does not equal (P0MATCH & P0MASK) or if (P1 & P1MASK) does not equal
(P1MATCH & P1MASK). This allows Software to be notified if a certain change or pattern occurs on P0 or
P1 input pins regardless of the XBRn settings. A port match event can cause an interrupt if EMAT (EIE2.1)
is set to '1' or cause the internal oscillator to awaken from SUSPEND mode. See Section “15.1.1. Internal
Oscillator Suspend Mode” on page 134 for more information.
SFR Definition 14.3. P0: Port0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
P0.7
P0.6
P0.5
P0.4
P0.3
P0.2
P0.1
P0.0
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0x80
Bits7–0: P0.[7:0]
Write - Output appears on I/O pins per Crossbar Registers.
0: Logic Low Output.
1: Logic High Output (high impedance if corresponding P0MDOUT.n bit = 0).
Read - Always reads ‘0’ if selected as analog input in register P0MDIN. Directly reads Port
pin when configured as digital input.
0: P0.n pin is logic low.
1: P0.n pin is logic high.
SFR Definition 14.4. P0MDIN: Port0 Input Mode
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
SFR Address: 0xF1
Bits7–0: Analog Input Configuration Bits for P0.7–P0.0 (respectively).
Port pins configured as analog inputs have their weak pullup, digital driver, and digital
receiver disabled.
0: Corresponding P0.n pin is configured as an analog input.
1: Corresponding P0.n pin is not configured as an analog input.
126
Rev. 0.3
C8051F52x-53x
SFR Definition 14.5. P0MDOUT: Port0 Output Mode
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0xA4
Bits7–0: Output Configuration Bits for P0.7–P0.0 (respectively): ignored if corresponding bit in register P0MDIN is logic 0.
0: Corresponding P0.n Output is open-drain.
1: Corresponding P0.n Output is push-pull.
(Note: When SDA and SCL appear on any of the Port I/O, each are open-drain regardless
of the value of P0MDOUT).
SFR Definition 14.6. P0SKIP: Port0 Skip
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xD4
Bits7–0: P0SKIP[7:0]: Port0 Crossbar Skip Enable Bits.
These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar.
0: Corresponding P0.n pin is not skipped by the Crossbar.
1: Corresponding P0.n pin is skipped by the Crossbar.
Rev. 0.3
127
C8051F52x-53x
SFR Definition 14.7. P0MAT: Port0 Match
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
SFR Address: 0xD7
Bits7–0: P0MAT[7:0]: Port0 Match Value.
These bits control the value that unmasked P0 Port pins are compared against. A Port
Match event is generated if (P0 & P0MASK) does not equal (P0MAT & P0MASK).
SFR Definition 14.8. P0MASK: Port0 Mask
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0xC7
Bits7–0: P0MASK[7:0]: Port0 Mask Value.
These bits select which Port pins will be compared to the value stored in P0MAT.
0: Corresponding P0.n pin is ignored and cannot cause a Port Match event.
1: Corresponding P0.n pin is compared to the corresponding bit in P0MAT.
128
Rev. 0.3
C8051F52x-53x
SFR Definition 14.9. P1: Port1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
P1.7
P1.6
P1.5
P1.4
P1.3
P1.2
P1.1
P1.0
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0x90
Bits7–0: P1.[7:0]
Write - Output appears on I/O pins per Crossbar Registers.
0: Logic Low Output.
1: Logic High Output (high impedance if corresponding P1MDOUT.n bit = 0).
Read - Always reads ‘0’ if selected as analog input in register P1MDIN. Directly reads Port
pin when configured as digital input.
0: P1.n pin is logic low.
1: P1.n pin is logic high.
SFR Definition 14.10. P1MDIN: Port1 Input Mode
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
SFR Address: 0xF2
Bits7–0: Analog Input Configuration Bits for P1.7–P1.0 (respectively).
Port pins configured as analog inputs have their weak pullup, digital driver, and digital
receiver disabled.
0: Corresponding P1.n pin is configured as an analog input.
1: Corresponding P1.n pin is not configured as an analog input.
Rev. 0.3
129
C8051F52x-53x
SFR Definition 14.11. P1MDOUT: Port1 Output Mode
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0xA5
Bits7–0: Output Configuration Bits for P1.7–P1.0 (respectively): ignored if corresponding bit in register P1MDIN is logic 0.
0: Corresponding P1.n Output is open-drain.
1: Corresponding P1.n Output is push-pull.
SFR Definition 14.12. P1SKIP: Port1 Skip
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xD5
Bits7–0: P1SKIP[7:0]: Port1 Crossbar Skip Enable Bits.
These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar.
0: Corresponding P1.n pin is not skipped by the Crossbar.
1: Corresponding P1.n pin is skipped by the Crossbar.
130
Rev. 0.3
C8051F52x-53x
SFR Definition 14.13. P0SKIP: Port0 Skip
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0xD4
Bits7–0: P1SKIP[7:0]: Port1 Crossbar Skip Enable Bits.
These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar.
0: Corresponding P1.n pin is not skipped by the Crossbar.
1: Corresponding P1.n pin is skipped by the Crossbar.
SFR Definition 14.14. P1MAT: Port1 Match
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
11111111
SFR Address: 0xCF
Bits7–0: P1MAT[7:0]: Port1 Match Value.
These bits control the value that unmasked P0 Port pins are compared against. A Port
Match event is generated if (P1 & P1MASK) does not equal (P1MAT & P1MASK).
SFR Definition 14.15. P1MASK: Port1 Mask
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xBF
Bits7–0: P1MASK[7:0]: Port1 Mask Value.
These bits select which Port pins will be compared to the value stored in P1MAT.
0: Corresponding P1.n pin is ignored and cannot cause a Port Match event.
1: Corresponding P1.n pin is compared to the corresponding bit in P1MAT.
Rev. 0.3
131
C8051F52x-53x
Table 14.1. Port I/O DC Electrical Characteristics
VREGIN = 2.7 to 5.25 V, –40 to +125 °C unless otherwise specified
Parameters
Output High Voltage
Output Low Voltage
Conditions
Min
Typ
Max
IOH = –3 mA, Port I/O push-pull
TBD
—
—
IOH = –10 µA, Port I/O push-pull
TBD
—
—
IOH = –10 mA, Port I/O push-pull
—
TBD
—
—
—
—
—
50
750
—
—
—
—
40
400
V = 2.7 V:
IOL = 70 µA
IOL = 8.5 mA
V = 5.25 V:
IOL = 70 µA
IOL = 8.5 mA
Units
V
mV
Input High Voltage
VREGIN = 5.25 V
3.6
—
—
V
Input Low Voltage
VREGIN = 2.7 V
—
—
0.7
V
Weak Pullup Off
Input Leakage Current Weak Pullup On, VIN = 0 V; V = 2.1 V
Weak Pullup On, VIN = 0 V; V = 2.6 V
—
—
—
—
< 0.11
< 0.14
±TBD
TBD
TBD
µA
132
Rev. 0.3
C8051F52x-53x
15. Oscillators
C8051F52x/53x devices include a programmable internal oscillator, an external oscillator drive circuit. The
internal oscillator can be enabled/disabled and calibrated using the OSCICN and OSCICL registers, as
shown in Figure 15.1. The system clock (SYSCLK) can be derived from the internal oscillator, external
oscillator circuit. Oscillator electrical specifications are given in Table 15.1 on page 142.
IFCN2
IFCN1
IFCN0
Option 3
XTAL2
CLKSEL
CLKSL1
CLKSL0
OSCIFIN
OSCICN
IOSCEN1
IOSCEN0
SUSPEND
IFRDY
OSCICL
Option 2
VDD
XTAL2
EN
IOSC
Programmable
Internal Clock
Generator
Option 1
n
XTAL1
Input
Circuit
10MΩ
EXOSC
OSC
SYSCLK
XFCN2
XFCN1
XFCN0
XTLVLD
XOSCMD2
XOSCMD1
XOSCMD0
Option 4
XTAL2
XTLVLD
XTAL2
OSCXCN
Figure 15.1. Oscillator Diagram
15.1. Programmable Internal Oscillator
All C8051F52x/53x devices include a programmable internal oscillator that defaults as the system clock
after a system reset. The internal oscillator period can be programmed via the OSCICL and OSCIFIN registers, shown in SFR Definition 15.2 and SFR Definition 15.3. On C8051F52x/53x devices, OSCICL and
OSCIFIN are factory calibrated to obtain a 24.5 MHz frequency.
Electrical specifications for the precision internal oscillator are given in Table 15.1 on page 142. Note that
the system clock may be derived from the programmed internal oscillator divided by 1, 2, 4, 8, 16, 32, 64,
or 128 as defined by the IFCN bits in register OSCICN. The divide value defaults to 128 following a reset.
Rev. 0.3
133
C8051F52x-53x
15.1.1. Internal Oscillator Suspend Mode
When software writes a logic 1 to SUSPEND (OSCICN.5), the internal oscillator is suspended. If the system clock is derived from the internal oscillator, the input clock to the peripheral or CIP-51 will be stopped
until one of the following events occur:
•
•
•
Port 0 Match Event.
Port 1 Match Event.
Comparator 0 enabled and output is logic 0.
When one of the internal oscillator awakening events occur, the internal oscillator, CIP-51, and affected
peripherals resume normal operation, regardless of whether the event also causes an interrupt. The CPU
resumes execution at the instruction following the write to SUSPEND.
134
Rev. 0.3
C8051F52x-53x
SFR Definition 15.1. OSCICN: Internal Oscillator Control
R/W
R/W
R/W
IOSCEN1 IOSCEN0 SUSPEND
Bit7
Bit6
Bit5
R
R
R/W
R/W
R/W
Reset Value
IFRDY
-
IFCN2
IFCN1
IFCN0
11000000
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xB2
Bit7–6:
IOSCEN[1:0]: Internal Oscillator Enable Bits.
00: Oscillator Disabled.
01: Oscillator Enabled in Normal Mode and Disabled in Suspend Mode.
10: Oscillator Enabled in Normal Mode and Disabled in Suspend Mode.
11: Oscillator Enabled in Normal Mode and Disabled in Suspend Mode, Low Power.
Bit5:
SUSPEND: Internal Oscillator Suspend Enable Bit.
Setting this bit to logic 1 places the internal oscillator in SUSPEND mode. The internal oscillator resumes operation when one of the SUSPEND mode awakening events occur.
Bit4:
IFRDY: Internal Oscillator Frequency Ready Flag.
0: Internal Oscillator is not running at programmed frequency.
1: Internal Oscillator is running at programmed frequency.
Bits3:
UNUSED. Read = 00b, Write = don't care.
Bits2–0: IFCN2–0: Internal Oscillator Frequency Control Bits.
000: SYSCLK derived from Internal Oscillator divided by 128 (default).
001: SYSCLK derived from Internal Oscillator divided by 64.
010: SYSCLK derived from Internal Oscillator divided by 32.
011: SYSCLK derived from Internal Oscillator divided by 16.
100: SYSCLK derived from Internal Oscillator divided by 8.
101: SYSCLK derived from Internal Oscillator divided by 4.
110: SYSCLK derived from Internal Oscillator divided by 2.
111: SYSCLK derived from Internal Oscillator divided by 1.
Rev. 0.3
135
C8051F52x-53x
SFR Definition 15.2. OSCICL: Internal Oscillator Calibration
R
R/W
R/W
R/W
Bit6
Bit5
Bit4
Bit7
R/W
R/W
R/W
R/W
Bit2
Bit1
Bit0
Reset Value
OSCICL
Varies
Bit3
SFR Address: 0xB3
Bit7:
UNUSED. Read = 0. Write = don’t care.
Bits 6–0: OSCICL: Internal Oscillator Calibration Register.
This register determines the internal oscillator period. On C8051F52x/53x devices, the reset
value is factory calibrated to generate an internal oscillator frequency of 24.5 MHz.
SFR Definition 15.3. OSCIFIN: Internal Fine Oscillator Calibration
R/W
R/W
-
-
Bit7
Bit6
R/W
R
R
R/W
Bit5
Bit4
Bit3
R/W
R/W
Bit1
Bit0
OSCIFIN
Bit2
Reset Value
undetermined
Bit Addressable
SFR Address: 0xB0
Bit7–6:
Bit5–0:
UNUSED. Read = 00b, Write = don't care.
OSCIFIN. Internal oscillator fine adjustment bits. The valid range is between 0x00 and 0x27.
This register is a fine adjustment for the internal oscillator period. On C8051F52x/53x devices, the
reset value is factory calibrated to generate an internal oscillator frequency of 24.5 MHz.
136
Rev. 0.3
C8051F52x-53x
15.2. External Oscillator Drive Circuit
The external oscillator circuit may drive an external crystal, ceramic resonator, capacitor, or RC network. A
CMOS clock may also provide a clock input. For a crystal or ceramic resonator configuration, the crystal/resonator must be wired across the XTAL1 and XTAL2 pins as shown in Option 1 of Figure 15.1. A
10 MΩ resistor also must be wired across the XTAL1 and XTAL2 pins for the crystal/resonator configuration. In RC, capacitor, or CMOS clock configuration, the clock source should be wired to the XTAL2 pin as
shown in Option 2, 3, or 4 of Figure 15.1. The type of external oscillator must be selected in the OSCXCN
register, and the frequency control bits (XFCN) must be selected appropriately (see SFR
Definition 15.4. OSCXCN: External Oscillator Control).
Important Note on External Oscillator Usage: Port pins must be configured when using the external
oscillator circuit. When the external oscillator drive circuit is enabled in crystal/resonator mode, Port pins
P0.7 and P1.0 (‘F53x) or P0.2 and P0.3 (‘F52x) are used as XTAL1 and XTAL2 respectively. When the
external oscillator drive circuit is enabled in capacitor, RC, or CMOS clock mode, Port pin P1.0 (‘F530) or
P0.3 (‘F52x) is used as XTAL2. The Port I/O Crossbar should be configured to skip the Port pins used by
the oscillator circuit; see Section “14.1. Priority Crossbar Decoder” on page 119 for Crossbar configuration.
Additionally, when using the external oscillator circuit in crystal/resonator, capacitor, or RC mode, the associated Port pins should be configured as analog inputs. In CMOS clock mode, the associated pin should
be configured as a digital input. See Section “14.2. Port I/O Initialization” on page 123 for details on Port
input mode selection.
15.2.1. Clocking Timers Directly Through the External Oscillator
The external oscillator source divided by eight is a clock option for the timers (Section “19. Timers” on
page 185) and the Programmable Counter Array (PCA) (Section “20. Programmable Counter Array
(PCA0)” on page 199). When the external oscillator is used to clock these peripherals, but is not used as
the system clock, the external oscillator frequency must be less than or equal to the system clock frequency. In this configuration, the clock supplied to the peripheral (external oscillator / 8) is synchronized
with the system clock; the jitter associated with this synchronization is limited to ±0.5 system clock cycles.
15.2.2. External Crystal Example
If a crystal or ceramic resonator is used as an external oscillator source for the MCU, the circuit should be
configured as shown in Figure 15.1, Option 1. The External Oscillator Frequency Control value (XFCN)
should be chosen from the Crystal column of the table in SFR Definition 15.4. For example, a 12 MHz crystal requires an XFCN setting of 111b.
Rev. 0.3
137
C8051F52x-53x
When the crystal oscillator is first enabled, the oscillator amplitude detection circuit requires a settling time
to achieve proper bias. Introducing a delay of 1 ms between enabling the oscillator and checking the
XTLVLD bit will prevent a premature switch to the external oscillator as the system clock. Switching to the
external oscillator before the crystal oscillator has stabilized can result in unpredictable behavior. The recommended procedure is:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Configure XTAL1 and XTAL2 pins by writing ‘1' to the port latch.
Configure XTAL1 and XTAL2 as analog inputs.
Enable the external oscillator.
Wait at least 1 ms.
Poll for XTLVLD => '1'.
Switch the system clock to the external oscillator.
Note: Tuning-fork crystals may require additional settling time before XTLVLD returns a valid result.
The capacitors shown in the external crystal configuration provide the load capacitance required by the
crystal for correct oscillation. These capacitors are "in series" as seen by the crystal and "in parallel" with
the stray capacitance of the XTAL1 and XTAL2 pins.
Note: The load capacitance depends upon the crystal and the manufacturer. Please refer to the crystal
data sheet when completing these calculations.
For example, a tuning-fork crystal of 32 kHz with a recommended load capacitance of 12.5 pF should use
the configuration shown in Figure 15.1, Option 1. The total value of the capacitors and the stray capacitance of the XTAL pins should equal 25 pF. With a stray capacitance of 3 pF per pin, the 22 pF capacitors
yield an equivalent capacitance of 12.5 pF across the crystal, as shown in Figure 15.2.
22 pF
XTAL1
Ω
10 MΩ
32 kHz
XTAL2
22 pF
Figure 15.2. 32 kHz External Crystal Example
Important Note on External Crystals: Crystal oscillator circuits are quite sensitive to PCB layout. The
crystal should be placed as close as possible to the XTAL pins on the device. The traces should be as
short as possible and shielded with ground plane from any other traces which could introduce noise or
interference.
138
Rev. 0.3
C8051F52x-53x
15.2.3. External RC Example
If an RC network is used as an external oscillator source for the MCU, the circuit should be configured as
shown in Figure 15.1, Option 2. The capacitor should be no greater than 100 pF; however for very small
capacitors, the total capacitance may be dominated by parasitic capacitance in the PCB layout. To determine the required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, first
select the RC network value to produce the desired frequency of oscillation. If the frequency desired is
100 kHz, let R = 246 kΩ and C = 50 pF:
f = 1.23( 103 ) / RC = 1.23 ( 103 ) / [ 246 x 50 ] = 0.1 MHz = 100 kHz
Referring to the table in SFR Definition 15.4, the required XFCN setting is 010b. Programming XFCN to a
higher setting in RC mode will improve frequency accuracy at a slightly increased external oscillator supply
current.
15.2.4. External Capacitor Example
If a capacitor is used as an external oscillator for the MCU, the circuit should be configured as shown in
Figure 15.1, Option 3. The capacitor should be no greater than 100 pF; however for very small capacitors,
the total capacitance may be dominated by parasitic capacitance in the PCB layout. To determine the
required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, select the frequency of oscillation and calculate the capacitance to be used from the equations below. Assume
VDD = 2.1 V and f = 75 kHz:
f = KF / (C x VDD)
0.075 MHz = KF / (C x 2.1)
Since the frequency of roughly 75 kHz is desired, select the K Factor from the table in SFR Definition 15.4
as KF = 7.7:
0.075 MHz = 7.7 / (C x 2.1)
C x 2.1 = 7.7 / 0.075 MHz
C = 102.6 / 2.0 pF = 51.3 pF
Therefore, the XFCN value to use in this example is 010b.
Rev. 0.3
139
C8051F52x-53x
SFR Definition 15.4. OSCXCN: External Oscillator Control
R
R/W
R/W
R/W
R/W
XTLVLD XOSCMD2 XOSCMD1 XOSCMD0 Reserved
Bit7
Bit6
Bit5
Bit4
Bit3
R/W
R/W
R/W
Reset Value
XFCN2
XFCN1
XFCN0
00000000
Bit2
Bit1
Bit0
SFR Address: 0xB1
Bit7:
XTLVLD: Crystal Oscillator Valid Flag. (Read only when XOSCMD = 11x.)
0: Crystal Oscillator is unused or not yet stable.
1: Crystal Oscillator is running and stable.
Bits6–4: XOSCMD2–0: External Oscillator Mode Bits.
00x: External Oscillator circuit off.
010: External CMOS Clock Mode.
011: External CMOS Clock Mode with divide by 2 stage.
100: RC Oscillator Mode.
101: Capacitor Oscillator Mode.
110: Crystal Oscillator Mode.
111: Crystal Oscillator Mode with divide by 2 stage.
Bit3:
RESERVED. Read = 0b; Must write 0b.
Bits2–0: XFCN2–0: External Oscillator Frequency Control Bits.
000-111: See table below:
XFCN
000
001
010
011
100
101
110
111
Crystal (XOSCMD = 11x)
f ≤ 20 kHz
20 kHz < f ≤ 58 kHz
58 kHz < f ≤ 155 kHz
155 kHz < f ≤ 415 kHz
415 kHz < f ≤ 1.1 MHz
1.1 MHz < f ≤ 3.1 MHz
3.1 MHz < f ≤ 8.2 MHz
8.2 MHz < f ≤ 25 MHz
RC (XOSCMD = 10x)
f ≤ 25 kHz
25 kHz < f ≤ 50 kHz
50 kHz < f ≤ 100 kHz
100 kHz < f ≤ 200 kHz
200 kHz < f ≤ 400 kHz
400 kHz < f ≤ 800 kHz
800 kHz < f ≤ 1.6 MHz
1.6 MHz < f ≤ 3.2 MHz
Crystal Mode (Circuit from Figure 15.1, Option 1; XOSCMD = 11x)
Choose XFCN value to match crystal or resonator frequency.
RC Mode (Circuit from Figure 15.1, Option 2; XOSCMD = 10x)
Choose XFCN value to match frequency range:
f = 1.23(103) / (R x C), where
f = frequency of clock in MHz
C = capacitor value in pF
R = Pullup resistor value in kΩ
C Mode (Circuit from Figure 15.1, Option 3; XOSCMD = 10x)
Choose K Factor (KF) for the oscillation frequency desired:
f = KF / (C x VDD), where
f = frequency of clock in MHz
C = capacitor value the XTAL2 pin in pF
VDD = Power Supply on MCU in volts
140
Rev. 0.3
C (XOSCMD = 10x)
K Factor = 0.87
K Factor = 2.6
K Factor = 7.7
K Factor = 22
K Factor = 65
K Factor = 180
K Factor = 664
K Factor = 1590
C8051F52x-53x
15.3. System Clock Selection
The internal oscillator requires little start-up time and may be selected as the system clock immediately following the OSCICN write that enables the internal oscillator. External crystals and ceramic resonators typically require a start-up time before they are settled and ready for use. The Crystal Valid Flag (XTLVLD in
register OSCXCN) is set to ‘1’ by hardware when the external oscillator is settled. To avoid reading a
false XTLVLD, in crystal mode software should delay at least 1 ms between enabling the external
oscillator and checking XTLVLD. RC and C modes typically require no startup time.
The CLKSL bit in register CLKSEL selects which oscillator source is used as the system clock. CLKSL
must be set to ‘1’ for the system clock to run from the external oscillator; however the external oscillator
may still clock certain peripherals (timers, PCA) when another oscillator is selected as the system clock.
The system clock may be switched on-the-fly between the internal oscillator and external oscillator, as long
as the selected clock source is enabled and has settled.
SFR Definition 15.5. CLKSEL: Clock Select
R
R
-
-
Bit7
Bit6
R/W
R/W
Reserved Reserved
Bit5
Bit4
R
Bit3
R/W
R/W
Reserved Reserved
Bit2
Bit1
R/W
Reset Value
CLKSL
00000000
Bit0
SFR Address: 0xA9
Bits7–6:
Bits5–4:
Bit3:
Bits2–1:
Bit0:
Unused. Read = 00b; Write = don’t care.
Reserved. Read = 0b; Must write 0b.
Unused. Read = 0b; Write = don’t care.
Reserved. Read = 0b; Must write 0b.
CLKSL: System Clock Select
0: Internal Oscillator (as determined by the IFCN bits in register OSCICN).
1: External Oscillator.
Rev. 0.3
141
C8051F52x-53x
Table 15.1. Oscillator Electrical Characteristics
VDD = 2.1 V, –40 to +125 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
Reset Frequency
24
24.5
25
MHz
Internal Oscillator ON
OSCICN.7 = 0
OSCICN.6 = 0
—
5.1
—
mA
Internal Oscillator OFF (Suspend)
OSCICN.7 = 0
OSCICN.6 = 1
—
214
—
µA
Internal Oscillator OFF (Suspend)
OSCICN.7 = 1
OSCICN.6 = 0
—
380
—
µA
Internal Oscillator OFF (Suspend)
OSCICN.7 = 1
OSCICN.6 = 1
—
0.5
—
µA
Internal Oscillator Frequency
Table 15.2. Oscillator Wake-Up Time from Suspend Mode
VDD = 2.1 V, –40 to +125 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
Wake-up Time
OSCICN.7 = 0
OSCICN.6 = 1
—
1
—
Instruction Cycles
Wake-up Time
OSCICN.7 = 1
OSCICN.6 = 0
—
1
—
Instruction Cycles
Wake-up Time
OSCICN.7 = 1
OSCICN.6 = 1
—
1.5
—
µs
142
Rev. 0.3
C8051F52x-53x
16. UART0
UART0 is an asynchronous, full duplex serial port offering modes 1 and 3 of the standard 8051 UART.
Enhanced baud rate support allows a wide range of clock sources to generate standard baud rates (details
in Section “16.1. Enhanced Baud Rate Generation” on page 144). Received data buffering allows UART0
to start reception of a second incoming data byte before software has finished reading the previous data
byte. (Please refer to Section “21. Revision Specific Behavior” on page 215 for more information on the pins
associated with the UART interface.)
UART0 has two associated SFRs: Serial Control Register 0 (SCON0) and Serial Data Buffer 0 (SBUF0).
The single SBUF0 location provides access to both transmit and receive registers. Writes to SBUF0
always access the Transmit register. Reads of SBUF0 always access the buffered Receive register;
it is not possible to read data from the Transmit register.
With UART0 interrupts enabled, an interrupt is generated each time a transmit is completed (TI0 is set in
SCON0), or a data byte has been received (RI0 is set in SCON0). The UART0 interrupt flags are not
cleared by hardware when the CPU vectors to the interrupt service routine. They must be cleared manually
by software, allowing software to determine the cause of the UART0 interrupt (transmit complete or receive
complete).
SFR Bus
Write to
SBUF
TB8
SBUF
(TX Shift)
SET
D
Q
TX
CLR
Crossbar
Zero Detector
Stop Bit
Shift
Start
Data
Tx Control
Tx Clock
Send
Tx IRQ
TI
MCE
REN
TB8
RB8
TI
RI
SMODE
SCON
UART Baud
Rate Generator
RI
Serial
Port
Interrupt
Port I/O
Rx IRQ
Rx Clock
Rx Control
Start
Shift
0x1FF
RB8
Load
SBUF
Input Shift Register
(9 bits)
Load SBUF
SBUF
(RX Latch)
Read
SBUF
SFR Bus
RX
Crossbar
Figure 16.1. UART0 Block Diagram
Rev. 0.3
143
C8051F52x-53x
16.1. Enhanced Baud Rate Generation
The UART0 baud rate is generated by Timer 1 in 8-bit auto-reload mode. The TX clock is generated by
TL1; the RX clock is generated by a copy of TL1 (shown as RX Timer in Figure 16.2), which is not useraccessible. Both TX and RX Timer overflows are divided by two to generate the TX and RX baud rates.
The RX Timer runs when Timer 1 is enabled, and uses the same reload value (TH1). However, an
RX Timer reload is forced when a START condition is detected on the RX pin. This allows a receive to
begin any time a START is detected, independent of the TX Timer state.
Timer 1
TL1
UART
Overflow
2
TX Clock
Overflow
2
RX Clock
TH1
Start
Detected
RX Timer
Figure 16.2. UART0 Baud Rate Logic
Timer 1 should be configured for Mode 2, 8-bit auto-reload (see Section “19.1.3. Mode 2: 8-bit
Counter/Timer with Auto-Reload” on page 187). The Timer 1 reload value should be set so that overflows
will occur at two times the desired UART baud rate frequency. Note that Timer 1 may be clocked by one of
six sources: SYSCLK, SYSCLK / 4, SYSCLK / 12, SYSCLK / 48, the external oscillator clock / 8, or an
external input T1. The UART0 baud rate is determined by Equation 16.1-A and Equation 16.1-B.
A) UartBaudRate = 1--- x T1_Overflow_Rate
2
B)
T1 CLK
T1_Overflow_Rate = -------------------------256 – TH1
Equation 16.1. UART0 Baud Rate
Where T1CLK is the frequency of the clock supplied to Timer 1, and T1H is the high byte of Timer 1 (8-bit
auto-reload mode reload value). Timer 1 clock frequency is selected as described in Section “19. Timers”
on page 185. A quick reference for typical baud rates and system clock frequencies is given in Table 16.1.
Note that the internal oscillator may still generate the system clock when the external oscillator is driving
Timer 1.
144
Rev. 0.3
C8051F52x-53x
16.2. Operational Modes
UART0 provides standard asynchronous, full duplex communication. The UART mode (8-bit or 9-bit) is
selected by the S0MODE bit (SCON0.7). Typical UART connection options are shown below.
TX
RS-232
LEVEL
XLTR
RS-232
RX
C8051Fxxx
OR
TX
TX
RX
RX
MCU
C8051Fxxx
Figure 16.3. UART Interconnect Diagram
16.2.1. 8-Bit UART
8-Bit UART mode uses a total of 10 bits per data byte: one start bit, eight data bits (LSB first), and one stop
bit. Data are transmitted LSB first from the TX0 pin and received at the RX0 pin. On receive, the eight data
bits are stored in SBUF0 and the stop bit goes into RB80 (SCON0.2).
Data transmission begins when software writes a data byte to the SBUF0 register. The TI0 Transmit Interrupt Flag (SCON0.1) is set at the end of the transmission (the beginning of the stop-bit time). Data reception can begin any time after the REN0 Receive Enable bit (SCON0.4) is set to logic 1. After the stop bit is
received, the data byte will be loaded into the SBUF0 receive register if the following conditions are met:
RI0 must be logic 0, and if MCE0 is logic 1, the stop bit must be logic 1. In the event of a receive data overrun, the first received 8 bits are latched into the SBUF0 receive register and the following overrun data bits
are lost.
If these conditions are met, the eight bits of data is stored in SBUF0, the stop bit is stored in RB80 and the
RI0 flag is set. If these conditions are not met, SBUF0 and RB80 will not be loaded and the RI0 flag will not
be set. An interrupt will occur if enabled when either TI0 or RI0 is set.
MARK
SPACE
START
BIT
D0
D1
D2
D3
D4
D5
D6
D7
STOP
BIT
BIT TIMES
BIT SAMPLING
Figure 16.4. 8-Bit UART Timing Diagram
Rev. 0.3
145
C8051F52x-53x
16.2.2. 9-Bit UART
9-bit UART mode uses a total of eleven bits per data byte: a start bit, 8 data bits (LSB first), a programmable ninth data bit, and a stop bit. The state of the ninth transmit data bit is determined by the value in TB80
(SCON0.3), which is assigned by user software. It can be assigned the value of the parity flag (bit P in register PSW) for error detection, or used in multiprocessor communications. On receive, the ninth data bit
goes into RB80 (SCON0.2) and the stop bit is ignored.
Data transmission begins when an instruction writes a data byte to the SBUF0 register. The TI0 Transmit
Interrupt Flag (SCON0.1) is set at the end of the transmission (the beginning of the stop-bit time). Data
reception can begin any time after the REN0 Receive Enable bit (SCON0.4) is set to ‘1’. After the stop bit
is received, the data byte will be loaded into the SBUF0 receive register if the following conditions are met:
(1) RI0 must be logic 0, and (2) if MCE0 is logic 1, the 9th bit must be logic 1 (when MCE0 is logic 0, the
state of the ninth data bit is unimportant). If these conditions are met, the eight bits of data are stored in
SBUF0, the ninth bit is stored in RB80, and the RI0 flag is set to ‘1’. If the above conditions are not met,
SBUF0 and RB80 will not be loaded and the RI0 flag will not be set to ‘1’. A UART0 interrupt will occur if
enabled when either TI0 or RI0 is set to ‘1’.
MARK
SPACE
START
BIT
D0
D1
D2
D3
D4
D5
D6
D7
D8
STOP
BIT
BIT TIMES
BIT SAMPLING
Figure 16.5. 9-Bit UART Timing Diagram
16.3. Multiprocessor Communications
9-Bit UART mode supports multiprocessor communication between a master processor and one or more
slave processors by special use of the ninth data bit. When a master processor wants to transmit to one or
more slaves, it first sends an address byte to select the target(s). An address byte differs from a data byte
in that its ninth bit is logic 1; in a data byte, the ninth bit is always set to logic 0.
Setting the MCE0 bit (SCON0.5) of a slave processor configures its UART such that when a stop bit is
received, the UART will generate an interrupt only if the ninth bit is logic 1 (RB80 = 1) signifying an address
byte has been received. In the UART interrupt handler, software will compare the received address with
the slave's own assigned 8-bit address. If the addresses match, the slave will clear its MCE0 bit to enable
interrupts on the reception of the following data byte(s). Slaves that weren't addressed leave their MCE0
bits set and do not generate interrupts on the reception of the following data bytes, thereby ignoring the
data. Once the entire message is received, the addressed slave resets its MCE0 bit to ignore all transmissions until it receives the next address byte.
Multiple addresses can be assigned to a single slave and/or a single address can be assigned to multiple
slaves, thereby enabling "broadcast" transmissions to more than one slave simultaneously. The master
processor can be configured to receive all transmissions or a protocol can be implemented such that the
master/slave role is temporarily reversed to enable half-duplex transmission between the original master
and slave(s).
146
Rev. 0.3
C8051F52x-53x
Master
Device
RX
TX
Slave
Device
RX
TX
Slave
Device
RX
TX
Slave
Device
RX
V+
TX
Figure 16.6. UART Multi-Processor Mode Interconnect Diagram
Rev. 0.3
147
C8051F52x-53x
SFR Definition 16.1. SCON0: Serial Port 0 Control
R/W
R
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
S0MODE
-
MCE0
REN0
TB80
RB80
TI0
RI0
01000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0x98
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
148
S0MODE: Serial Port 0 Operation Mode.
This bit selects the UART0 Operation Mode.
0: 8-bit UART with Variable Baud Rate.
1: 9-bit UART with Variable Baud Rate.
UNUSED. Read = 1b. Write = don’t care.
MCE0: Multiprocessor Communication Enable.
The function of this bit is dependent on the Serial Port 0 Operation Mode.
S0MODE = 0: Checks for valid stop bit.
0: Logic level of stop bit is ignored.
1: RI0 will only be activated if stop bit is logic level 1.
S0MODE = 1: Multiprocessor Communications Enable.
0: Logic level of ninth bit is ignored.
1: RI0 is set and an interrupt is generated only when the ninth bit is logic 1.
REN0: Receive Enable.
This bit enables/disables the UART receiver.
0: UART0 reception disabled.
1: UART0 reception enabled.
TB80: Ninth Transmission Bit.
The logic level of this bit will be assigned to the ninth transmission bit in 9-bit UART Mode. It
is not used in 8-bit UART Mode. Set or cleared by software as required.
RB80: Ninth Receive Bit.
RB80 is assigned the value of the STOP bit in Mode 0; it is assigned the value of the 9th
data bit in Mode 1.
TI0: Transmit Interrupt Flag.
Set by hardware when a byte of data has been transmitted by UART0 (after the 8th bit in 8bit UART Mode, or at the beginning of the STOP bit in 9-bit UART Mode). When the UART0
interrupt is enabled, setting this bit causes the CPU to vector to the UART0 interrupt service
routine. This bit must be cleared manually by software.
RI0: Receive Interrupt Flag.
Set to ‘1’ by hardware when a byte of data has been received by UART0 (set at the STOP bit
sampling time). When the UART0 interrupt is enabled, setting this bit to ‘1’ causes the CPU
to vector to the UART0 interrupt service routine. This bit must be cleared manually by software.
Rev. 0.3
C8051F52x-53x
SFR Definition 16.2. SBUF0: Serial (UART0) Port Data Buffer
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0x99
Bits7–0: SBUF0[7:0]: Serial Data Buffer Bits 7–0 (MSB–LSB)
This SFR accesses two registers; a transmit shift register and a receive latch register. When
data is written to SBUF0, it goes to the transmit shift register and is held for serial transmission. Writing a byte to SBUF0 initiates the transmission. A read of SBUF0 returns the contents of the receive latch.
Rev. 0.3
149
C8051F52x-53x
SYSCLK from
Internal Osc.
Table 16.1. Timer Settings for Standard Baud Rates
Using the Internal Oscillator
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
2400
1200
Baud Rate
% Error
–0.32%
–0.32%
0.15%
–0.32%
0.15%
–0.32%
–0.32%
0.15%
Frequency: 24.5 MHz
OscillaSCA1–SCA0
Timer Clock
tor Divide
(pre-scale
Source
Factor
select)*
106
SYSCLK
XX
212
SYSCLK
XX
426
SYSCLK
XX
848
SYSCLK / 4
01
1704
SYSCLK / 12
00
2544
SYSCLK / 12
00
10176
SYSCLK / 48
10
20448
SYSCLK / 48
10
X = Don’t care
T1M*
1
1
1
0
0
0
0
0
*Note: SCA1–SCA0 and T1M bit definitions can be found in Section 19.1.
150
Rev. 0.3
Timer 1
Reload
Value (hex)
0xCB
0x96
0x2B
0x96
0xB9
0x96
0x96
0x2B
C8051F52x-53x
17. LIN (C8051F520/523/526/530/533/536 only)
LIN is an asynchronous, serial communications interface used primarily in automotive networks. This document assumes previous knowledge of the interface. For more information about the LIN concept including
specifications please refer to the LIN consortium (http://www.lin-subbus.org/).
17.1. Major Characteristics
Silicon Laboratories LIN peripheral implements a complete LIN interface and presents the following features:
1. Selectable Master and Slave Modes
2. Unique Self-Synchronization without a quartz crystal or ceramic resonator in both Master and
Slave modes. Silicon Laboratories innovative internal oscillator design technology allows the
oscillator to reach 0.5% precision across the entire supply voltage and temperature range.
3. Fully configurable transmission/reception characteristics via SFRs
Important: The minimum system clock (SYSCLK) to be used when using the LIN peripheral is
8 MHz.
The following Figure describes LIN main blocks.
REGISTERS
BLOCK
LINCTRL
LINST
LINERR
LINSIZE
LINDIV
LINMUL
LIN INTERFACE
REGISTERS
LINID
LINCF
rxd
CONTROL FSM & BIT
STREAMING LOGIC
LINDATA
LINADDR
txd
DATA BUFFER
LINDT1
LINDT2
LINDT3
LINDT4
LINDT5
LINDT6
LINDT7
LINDT8
Figure 17.1. LIN Flowchart
Rev. 0.3
151
C8051F52x-53x
The LIN peripheral is made of four major logic groups:
•
•
•
•
LIN Interface Registers - Provide the interface between the microcontroller core and the peripheral.
Data Buffer - Contains the registers where transmitted and received message data bytes are placed
Registers Block - Contain all registers used to control the functionality of the interface
Control State Machine and Bit Streaming Logic - Contains the hardware the serializes messages and
the timing control of the peripheral.
The LIN module does not directly support LIN Version 1.3 Extended Frames. In the case of a slave configuration if the application detects an extended frame it has to write a ‘1’ to the STOP bit (LINCTRL) instead
of setting the DTACK bit (steps 1b...1e can then be skipped). In that case the LIN peripheral stops the processing of the LIN communication until the next SYNC BREAK is received.
17.2. Software Interface with the LIN Peripheral
The communication with the LIN interface is done indirectly through a pair of registers called LINADDR
and LINDATA and the Selection of the mode (Master or Slave) and the automatic baud rate feature are
done though the LINCF register. To write into a specific register other than these three ones require the
user to first load the LINADDR register with the address of the required LIN register and then load the data
to be transferred to the register using LINDATA.
In the following example the program reads the value of the LIN ERR Register into an auxiliary variable.
152
LINADDR = 0x0A;
//Address of LINERR
aux = LINDATA;
//Read content of LINERR into aux
Rev. 0.3
C8051F52x-53x
17.3. LIN Registers
The following Special Function Registers (SFRs) are available:
17.3.1. LIN Direct Access SFR Registers Definition
SFR Definition 17.1. LINADDR: Indirect Address Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x92
Bit7–0:
LINADDR[7:0] LIN address Register
SFR Definition 17.2. LINDATA: LIN Data Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0x93
Bit7–0:
LINDATA[7:0] LIN Data Register
SFR Definition 17.3. LINCF Control Mode Register
R/W
R/W
R/W
LINEN
MODE
ABAUD
Bit7
Bit6
Bit5
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x95
Bit7:
Bit6:
Bit5:
LINEN: LIN Interface Enable bit
1 - Enabled
0 - Disabled
MODE: LIN Mode Selection
1 - Master Mode
0 - Slave Mode
ABAUD: LIN Mode Automatic Bit Rate Selection (slave mode only)
1 - Automatic bit-rate Selection
0 - Manual bit-rate Selection.
Rev. 0.3
153
C8051F52x-53x
17.3.2. LIN Indirect Access SFR Registers Definition
Table 17.1. LIN Registers* (Indirectly Addressable)
Name
Addres
s
LINDT1
0x00
data byte 0[7:0]
LINDT2
0x01
data byte 1[7:0]
LINDT3
0x02
data byte 2[7:0]
LINDT4
0x03
data byte 3[7:0]
LINDT5
0x04
data byte 4[7:0]
LINDT6
0x05
data byte 5[7:0]
LINDT7
0x06
data byte 6[7:0]
LINDT8
0x07
data byte 7[7:0]
LINCTRL
0x08
STOP(s)
SLEEP(s)
LINST
0x09
ACTIVE
IDLTOUT
LINERR
0x0A
LINSIZE
0x0B
LINDIV
0x0C
LINMUL
0x0D
LINID
0x0E
Bit7
Bit6
Bit5
Bit4
TXRX
Bit3
DTACK(s)
ABORT(s) DTREQ(s)
Bit2
Bit1
Bit0
RSTINT RSTERR WUPREQ STREQ(m)
LININT
SYNCH(s) PRTY(s)
ERROR WAKEUP
TOUT
ENHCHK
CHK
DONE
BITERR
data length [3:0]
baud divider[7:0]
PRESCL1 PRESCL0
MUL4
MUL3
MUL2
MUL1
MUL0
DIV
ID5
ID4
ID3
ID2
ID1
ID0
*These registers are used in both master and slave mode. The register bits marked with (m) are
accessible only in Master mode while the register bits marked with (s) are accessible only in slave
mode. All other registers are accessible in both modes.
SFR Definition 17.4. LINDT1: LIN Data Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address:
Bit7–0:
154
LINDT1: Serial Data Byte Received or transmitted by the interface
Rev. 0.3
0x00
(indirect)
C8051F52x-53x
SFR Definition 17.5. LINDT2: LIN Data Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7–0:
0x01
(indirect)
LINDT2: Serial Data Byte Received or transmitted by the interface
SFR Definition 17.6. LINDT3: LIN Data Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7–0:
0x02
(indirect)
LINDT3: Serial Data Byte Received or transmitted by the interface
SFR Definition 17.7. LINDT4: LIN Data Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address:
Bit7–0:
0x03
(indirect)
LINDT4: Serial Data Byte Received or transmitted by the interface
SFR Definition 17.8. LINDT5: LIN Data Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7–0:
0x04
(indirect)
LINDT5: Serial Data Byte Received or transmitted by the interface
Rev. 0.3
155
C8051F52x-53x
SFR Definition 17.9. LINDT6: LIN Data Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7–0:
0x05
(indirect)
LINDT6: Serial Data Byte Received or transmitted by the interface
SFR Definition 17.10. LINDT7: LIN Data Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address:
Bit7–0:
0x06
(indirect)
LINDT7: Serial Data Byte Received or transmitted by the interface
SFR Definition 17.11. LINDT8: LIN Data Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7–0:
156
LINDT8: Serial Data Byte Received or transmitted by the interface
Rev. 0.3
0x07
(indirect)
C8051F52x-53x
SFR Definition 17.12. LINCTRL: LIN Control Register
W
W
W
R/W
R/W
STOP
SLEEP
TXRX
DTACK
RSTINT
Bit7
Bit6
Bit5
Bit4
Bit3
R/W
R/W
RSTERR WUPREQ
Bit2
Bit1
R/W
Reset Value
STREQ
00000000
Bit0
SFR Address:
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
0x08
(indirect)
STOP: Blocks processing of LIN communications (slave mode only).
This bit is to be set by the application to block the processing of the LIN Communications
until the next SYNCH BREAK signal. It is used when the application is handling a data
request interrupt and cannot use the frame content with the received identifier (always reads
‘0’).
SLEEP: Sleep Mode Warning.
This bit is to be set by the application to warn the peripheral that a Sleep Mode Frame was
received and that the Bus is in sleep mode or if a Bus Idle timeout interrupt is requested.
The application must reset it when a Wake-Up interrupt is requested.
TXRX: Transmit/Receive Selection Bit.
This bit is to be set by the application to select if the current frame is a transmit frame or a
receive frame.
1 - Transmit Operation
0 - Receive Operation
DTACK: Data acknowledge bit.(slave mode only)
This bit is to be set by the application after handling a data request interrupt (reset by the
peripheral.)
RSTINT: Interrupt Reset bit.
This bit must be set by the application to reset the “INT” bit in the LINST (LIN Status Register).
RSTERR: Error Reset Bit
The application must set this bit in order to reset the error bits in the LINST (LIN Status Register) and the LINERR (LIN Error Register) bits.
WUPREQ: Wake-Up Request Bit.
This bit must be set by the application to end the sleep mode of the LIN bus by sending a
Wake-Up Signal. (reset by the peripheral)
STREQ: Start Request Bit.(master mode only)
This bit must be set by the application to start a LIN transmission. It may be done only after
loading the identifier, data length and data buffer.(reset by the peripheral upon completion of
the transmission or error detection).
LIN Mode Selection
Status of the
Peripheral
Event
Slave (LINCF.6 = 0)
Sleeping
Slave (LINCF.6 = 0)
Sleeping
Wake-Up Pulse Received WAKEUP Bit Set (LINST.1 = 1)
DONE Bit Set (LINST.0 = 1)
Valid Frame Received
Master (LINCF.6 = 1)
Sleeping
Wake-Up Pulse Received
Rev. 0.3
Result
157
C8051F52x-53x
SFR Definition 17.13. LINST: LIN STATUS Register
R
R
R
R
R/W
R
R
R
Reset Value
ACTIVE
IDLTOUT
ABORT
DTREQ
LININT
ERROR
WAKEUP
DONE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
158
0x09
(indirect)
ACTIVE: LIN Bus Activity Bit.
This bit shows when transmission activity in the bus is detected by the peripheral.
1 - Transmission activity detected by the peripheral
0 - No transmission detected by the peripheral.
IDLTOUT: Bus Idle Timeout.(slave mode only)
This bit is set by the peripheral if no bus activity is detected over a period of 4 seconds and
the SLEEP bit in the LINCTRL (LIN Control Register) is not set by the application. Upon setting this bit the peripheral also sets the interrupt Request Bit (LININT) and the applications
can then assume that the LIN bus is in sleep mode and set the SLEEP bit (LINCTRL.6).
ABORT: Aborted transmission signal.(slave mode only)
This bit is set by the peripheral when a new SYNCH BREAK signal is detected before the
end of the last transmission. The transmission is aborted and the new frame is processed.
This bit is also set when the application sets the STOP bit (from LINCTRL). Once a SYNCH
BREAK signal is received (if it doesn’t interrupt another transmission) this signal is reset.
DTREQ: Data Request bit.(slave mode only)
The peripheral sets this bit after receiving the Identifier and requests an interrupt. The application has then to perform the following actions:
1- Decode the Identifier to decide whether the current frame is a transmit or a receive operation.
2- Adjust the TXRX bit (in LINCTRL) and to load the data length.
3- In case of a transmit operation the application must load the data buffer.
4- Set the DTACK bit (data acknowledge) found in the LINCTRL register.
LININT: Interrupt Request bit.
This bit is set when an interrupt is issued and has to be reset by the application by setting
the RSTINT bit (LINCTRL)
ERROR: Communication Error Bit.
The peripheral sets the bit if an error has been detected. The bit has to be reset by the application by setting the RSTERR bit (LINCTRL).
WAKEUP: Wake-Up Request Bit.
The bit is set when the peripheral is transmitting a Wake-Up signal or has received a WakeUp signal.
DONE: Transmission Complete Bit.
The peripheral sets this bit at the end of a successful transmission and resets it at the start
of another transmission.
Rev. 0.3
C8051F52x-53x
SFR Definition 17.14. LINERR: LIN ERROR Register
R
Bit7
R
Bit6
R
Bit5
R
R
R
R
R
Reset Value
SYNCH
PRTY
TOUT
CHK
BITERR
00000000
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7–5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
0x0A
(indirect)
UNUSED. Read = 000b. Write = don’t care.
SYNCH: Synchronization Error bit.(slave mode only)
The peripheral detected edges of the SYNCH FIELD outside the maximum tolerance.
PRTY: Parity Error bit.(slave mode only)
This bit is set when a parity error is detected.
TOUT: Timeout Error Bit.
This bit is set whenever one of the following conditions is met:
1- The master detects a timeout error if it is expecting data from the bus but no slave does
respond.
2- If the slave responds to late and the frame is not finished within the maximum frame
length TFRAME_MAX.
3- The slave detects a timeout error if it is expecting data from the master or another slave
but no data is transmitted on the bus.
4- If the frame is not finished within the maximum frame length TFRAME_MAX is reached.
5- The slave detects a timeout error if it is requesting a data acknowledge to the application
(for selecting receive or transmit, data length and loading data) and the application does not
set the DTACK bit (LINCTRL) or STOP bit (LINCTRL) until the end of the reception of the
first byte after the identifier.
6- The slave detects a timeout error if it has transmitted a wakeup signal and it detects no
sync field (from the master) within 150 ms.
CHK: Checksum Error Bit.
The bit is set when the peripheral detects a checksum error.
BITERR: Bit Error bit.
This error bit is set when the bit value monitored by the peripheral is different from the one
sent.
Rev. 0.3
159
C8051F52x-53x
SFR Definition 17.15. LINSIZE: LIN Message Size Register
R/W
R/W
R/W
R/W
ENHCHK
-
-
-
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
R/W
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7:
Bit6–4:
Bit3–0:
Bit0:
Reset Value
LINSIZE3 LINSIZE2 LINSIZE1 LINSIZE0 00000000
0x0B
(indirect)
ENHCHK: Checksum version selection bit
1 - Spec. 2.0, inverted eight bit sum with carry over all data bytes and protected identifier.
0 - Spec 1.3, inverted eight bit sum with carry over all data bytes.
UNUSED. Read = 00b. Write = don’t care.
LINSIZE3–0: LIN data field size.
If the LINSIZE bits are filled (“1111b’) then the size of the data field is defined as a function of
the two most significative bits of the identifier as defined in the table below, otherwise is
defined by the LINSIZE3–0 bits.
ID5
ID4
Number of Bytes in the Data Field
0
0
2 bytes
0
1
2 bytes
1
0
4 bytes
1
1
8 bytes
UNUSED. Read = 00b. Write = don’t care.
SFR Definition 17.16. LINDIV: LIN Divider Register
R
R
R
R
R
R
R
R
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address:
Bit7–0:
160
0x0C
(indirect)
Baud Rate Divider [7:0].
This register contains the 8 least significative bits of the divider used to generate the baud
rate.
Rev. 0.3
C8051F52x-53x
SFR Definition 17.17. LINMUL: LIN Multiplier Register
R/W
R/W
PRESCL1 PRESCL0
Bit7
Bit6
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
MUL4
MUL3
MUL2
MUL1
MUL0
DIV
00000000
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7–6:
Bit5–1:
Bit0:
0x0D
(indirect)
PRESCL1–0:Prescaler used to create the baud rate.
MUL4–0: Multiplier used to create the baud rate.
DIV: Most significative bit of the divider used to create the baud rate.
SFR Definition 17.18. LINID: LIN ID Register
R/W
Bit7
R/W
Bit6
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
ID5
ID4
ID3
ID2
ID1
ID0
00000000
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
Bit7–6:
Bit5–0:
0x0E
(indirect)
UNUSED. Read = 00b. Write = don’t care.
ID5–0: Identifier
17.4. LIN Interface Setup and Operation
The Hardware based LIN peripheral allows for the implementation of both Master and Slave nodes with
minimal firmware overhead and complete control of the interface status while allowing for interrupt and
polled mode operation.
The first step to use the peripheral is to define the basic characteristics of the node to be implemented with
the microcontroller:
•Mode - Master or Slave
•Baud Rate - Either defined manually or using the autobaud feature (slave mode only) implemented in
the peripheral.
•Checksum Type - The peripheral implements both the Classic and the Enhanced Checksum formats
in Hardware.
17.4.1. Mode Definition
Following the LIN specification the peripheral implements in HW both the Slave and Master operating
modes. The following C-code fragment implements the master mode in the part:
LINCF |= 0x40;
// Master Mode Selected
Rev. 0.3
161
C8051F52x-53x
17.4.2. Bit Rate Options: Manual or Autobaud (Slave only)
The peripheral can be selected to have its bit rate calculated manually or automatically. A master node
must always have its bit rate set manually but for slave nodes the designer can choose between a manual
or automatic setup. The following C-code fragment shows how to select the peripheral to use manual baud
rate:
LINCF &= ~0x20;
// Manual Baud Rate
Both manual and automatic baud rate require the setup of some registers. The following chapters explain
the different options available and their relation with the baud rate along with the steps necessary to
achieve the required baud rate.
17.4.3. Baud Rate Calculations - Manual Mode
The baud rate used by the peripheral is a function of the System Clock (SYSCLK) and the bit-timing Registers according to the following equation:
SYSCLK
bit_rate = -----------------------------------------------------------------------------------------------------( prescaler + 1 )
2
× divider × ( multiplier + 1 )
The prescaler, divider and multiplier factors are part of the LINDIV and LINMUL registers and can assume
values in the following range:
Table 17.2. Table Needs Title
Factor
Range
prescaler
0…3
divider
0…31
multiplier
200…511
Important: The minimum system clock (SYSCLK) to operate the LIN peripheral is 8 MHz.
To calculate the value of the several factors used to create a required bit-rate the following equations are
defined:
20000
multiplier = --------------------- – 1
bit_rate
SYSCLK
1
prescaler = ln ------------------------------------------------------------------------------------ × -------- – 1
( multiplier + 1 ) × bit_rate × 200
ln2
SYSCLK
divider = ----------------------------------------------------------------------------------------------( prescaler + 1 )
(2
× m ultiplier × bit_rate )
162
Rev. 0.3
C8051F52x-53x
It is important to note that in all these equations the results must be rounded down to the nearest integer.
The following example calculates the factors for a Master node running at 24.5 MHz and communicating at
19.2 Kbits/sec. First, the multiplier will be calculated:
20000
multiplier = --------------- – 1 = 0.0417 ≅ 0
19200
After this step the prescaler is calculated:
24500000
1
prescaler = ln ----------------------------------------------------- × -------- – 1 = 1.674 ≅ 1
( 0 + 1 ) × 19200 × 200 ln2
Then the divider is calculated:
24500000
- = 319.010 ≅ 319
divider = -----------------------------------------------------------(1 + 1)
× ( 0 + 1 ) × 19200
2
These values will lead to the following bit_rate:
24500000
- ≅ 19200.63
bit_rate = -----------------------------------------------------(1 + 1)
× ( 0 + 1 ) × 319
2
The following code fragment programs the interface in Master mode, using the Enhanced Checksum and
enabling the interface to operate at 9600 bits/sec from a system clock (SYSCLK) of 24.5 MHz.
LINCF = 0x80;
// Activate the interface
LINADDR = 0x09;// Point to the status register
LINCF |= 0x40;// Set the part as Master
LINADDR = 0x0D;// Point to the LINMUL register
// Initialize the register (prescaler, multiplier and bit 8 of divider)
LINDATA = (_0x01 << 6 ) + (_0x00 << 1 ) + ( (_0x13F & 0x0100 ) >> 8 );
LINADDR = 0x0C;// Point to the LINDIV register
LINDATA = (unsigned char)_0x13F;// Initialize LINDIV
LINADDR = 0x0B;// Point to the LINSIZE register
LINDATA |= 0x80;
// Initialize the checksum as Enhanced
LINADDR = LINCTRL;
// Point to LINCTRL register
LINDATA = RSTERR | RSTINT;
// Reset any error and the interrupt
Table 17.3 presents some typical values of system clock and bit rate along with their factors:
Rev. 0.3
163
C8051F52x-53x
Table 17.3. Manual Bit-Rate Parameters Examples
325
1
1
325
3
1
325
19
1
312
1
319
1
1
319
3
1
319
19
1
306
24
0
1
300
0
1
312
1
1
312
3
1
312
19
1
300
22.1184
0
1
276
0
1
288
1
1
288
3
1
288
19
1
276
Div.
Pres.
1
0
Mult.
0
306
Div.
Pres.
312
1
Mult.
1
0
Div.
0
Mult.
25
24.5
Div.
Pres.
1K
Mult.
4.8 K
Div.
9.6 K
Pres.
19.2 K
Mult.
SYSCLK
(MHz)
20 K
Pres.
Baud
(bits/sec)
16
0
1
200
0
1
208
1
1
208
3
1
208
19
1
200
12.25
0
0
306
0
0
319
1
0
319
3
0
319
19
0
306
12
0
0
300
0
0
312
1
0
312
3
0
312
19
0
300
11.0592
0
0
276
0
0
288
1
0
288
3
0
288
19
0
276
8
0
0
200
0
0
208
1
0
208
3
0
208
19
0
200
17.4.4. Baud Rate Calculations - Automatic Mode
The designer may choose to use the automatic bit rate feature of the Slave Peripheral. In this case only the
prescaler and divider must be calculated as follows:
1
SYSCLK
prescaler = ln ---------------------- × -------- – 1
4000000
ln2
SYSCLK
divider = ----------------------------------------------------( prescaler + 1 )
2
× 20000
In the following example it is calculated the value of these factors for a system clock (SYSCLK) of
24.5 MHz:
24500000
1
prescaler = ln ------------------------ × -------- – 1 = 1.615 ≅ 1
4000000
ln2
24500000 divider = -----------------------------------= 306.25 ≅ 306
(1 + 1)
2
× 20000
Table 17.4 presents some typical values of system clock and bit rate along with their factors.
164
Rev. 0.3
C8051F52x-53x
Table 17.4. Autobaud Parameters Examples
SYSCLK
Prescaler
Divider
25,000,000
1
312
24,500,000
1
306
24,000,000
1
300
22,118,400
1
276
16,000,000
1
200
12,250,000
0
306
12,000,000
0
300
11,059,200
0
276
8,000,000
0
200
17.4.5. LIN Master Mode Operation
Once the node is properly configured it can operate. The master node is responsible for the scheduling of
messages and sends the header of each frame, containing the SYNCH BREAK FIELD, SYNCH FIELD
and IDENTIFIER FIELD. The steps to schedule a message are described in the following paragraphs.
1. Load the 6-bit Identifier into the ID register (LINID).
2. Load the "data length" in the LINSIZE register (number of data bytes or value "1111b" if the
data length should be decoded from the identifier) and set the checksum type (classic or
enhanced, defined by the ENHCHK bit also in the LINSIZE register).
3. Adjust the TXRX bit (LINCTRL.5):
"1" - If the current frame is a transmit operation for the master.
"0" - If the current frame is a receive operation for the master.
4. Load the data bytes to transmit into the data buffer (LINDT1 to LINDT8, only if this is a transmit
operation).
5. The STREQ bit (LINCTRL) is set to start the message transfer. After that the LIN peripheral
schedules the message frame and request an interrupt if the message transfer is successfully
completed or if an error is occurred.
Rev. 0.3
165
C8051F52x-53x
This code fragment shows the procedure to schedule a message in a transmission operation:
LINADDR = 0x08;
// Select to transmit data
LINDATA |= 0x20;
LINADDR = 0x0E;
// Point to ID
LINDATA = 0x11;
// Load the ID, in this example 0x11
LINADDR = 0x0B;
// Point to the size
// Load the size with 8
LINDATA = ( LINDATA & 0xF0 ) | 0x08;
LINADDR = 0x00;
// Point to Data buffer first byte
for(i=0;i<8;i++)
{
LINDATA = i + 0x41; // Load the buffer with 'A', 'B', 'C',……
LINADDR++;
}
LINADDR = LINCTRL;
// Start Transmission
LINDATA = 0x01;
The following steps have to be performed by the application when an interrupt is requested.
6. Check the DONE bit and the ERROR bit (LINST)
7. Load the received data from the data buffer if the transfer was successful (for receive operation only).
8. If the transfer was not successful, check the error register to determine the kind of error. Further error handling has to be done by the application.
9. Set the RSTINT and RSTERR bits in the status register (LINST) to reset the interrupt request
and the error flags.
17.4.6. LIN Slave Mode Operation
Once initialized the LIN peripheral in Slave Mode can operate. Access from application to data buffer and
ID registers of the LIN core slave is only possible when a data request is pending (DTREQ bit in LINST
register is '1') and also when the LIN bus is not active (ACTIVE bit in LINST register set to '0').
The LIN peripheral in slave mode detects the header of the message frame sent by the LIN master. If slave
synchronization is enabled (autobaud), the slave synchronizes its internal bit time to the master bit time.
An interrupt is requested in one of three situations:
•After the reception of the IDENTIFIER FIELD
•When an error is detected
•When the message transfer is completed.
The following steps have to be performed by the application when an interrupt is detected:
•Check the DTREQ bit in the status register (LINST) is set. (Set when the IDENTIFIER FIELD has
been received). If it is set then:
•Read the identifier from the LINID register and process it
•Adjust the TXRX bit in the control register (LINCTRL) (set to "1" if the current frame is a transmit operation for the slave and set to "0" if the current frame is a receive operation for the slave)
•Load the "data length" in the LINSIZE register (number of data bytes or value "1111b" if the data length
should be decoded from the identifier)
•Load the data to transmit into the data buffer. (for transmit operations only)
•Set the DTACK bit in the LINCTRL register.
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•Check the DONE bit in the status register if the DTREQ bit is not set. The transmission was successful if the DONE bit is set.
•If the transmission was successful and the current frame was a receive operation for the slave, load
the received data bytes from the data buffer. If not check the error register (LINERR) to determine
the nature of the error. Further error handling has to be done by the application.
•Set the RSTINT and RSTERR bits in the status register (LINCTRL) to reset the interrupt request and
the error flags.
In Addition to these steps the designer must consider the following:
1. Steps 1…5 have to be done during the IN-FRAME RESPONSE SPACE If the current frame is
a transmit operation for the slave; otherwise a timeout will be detected by the master. If the
current frame is a receive operation for the slave, steps 1…5 have to be finished until the
reception of the first byte after the IDENTIFIER FIELD. Otherwise, the internal receive buffer
of the LIN peripheral will be overwritten and a timeout error will be detected in the LIN peripheral.
2. If the application detects an unknown identifier (e.g. extended identifier) it has to write a '1' to
the STOP bit (LINCTRL) instead of setting the DTACK bit (steps 2…5 can then be skipped). In
that case the LIN peripheral stops the processing of the LIN communication until the next
SYNC BREAK is received.
3. Changing the setup of the checksum (classic to enhanced or vice versa) during a transaction
will cause the interface to reset and the transaction to be lost. Therefore no change in the
checksum should be performed while there is a transaction in progress. The same applies to
changes in the LIN interface mode from slave mode to master mode and from master mode to
slave mode.
17.4.7. Sleep Mode and Wake-Up
To reduce the systems power consumption the LIN Protocol Specification defines a Sleep Mode. The message used to broadcast a Sleep Mode request must be transmitted by the LIN master application in the
same way as a normal transmit message. The LIN slave application must decode the Sleep Mode Frame
from Identifier and data bytes. After that, it has to put the LIN slave node into the Sleep Mode by setting the
SLEEP bit in the control register (LINCTRL).
If the SLEEP bit in the control register (LINCTRL) of the LIN slave application is not set and there is no bus
activity for 4 s (specified bus idle timeout) the IDLTOUT bit in the status register (LINST) is set and an interrupt request is generated. After that the application may assume that the LIN bus is in Sleep Mode and set
the SLEEP bit in the control register (LINCTRL).
Sending a Wakeup signal from the master or any slave node terminates the Sleep Mode of the LIN bus. To
send a Wakeup signal, the application has to set the WUPREQ bit in the status register (LINST). After successful transmission of the wakeup signal the DONE bit in the status register (LINST) of the master node is
set and an interrupt request is generated. The LIN slave does not generate an interrupt request after successful transmission of the Wakeup signal but it generates an interrupt request if the master does not
respond to the Wakeup signal within 150 msec. In that case the ERROR bit in status register (LINST) and
TOUT bit in LINERR register are set. The application has to decide whether to transmit another Wakeup
signal or not.
All LIN nodes that detect a wakeup signal will set the WAKEUP and DONE bits in status register (LINST)
and generate an interrupt request. After that, the application has to clear the SLEEP bit in the control register of the LIN slave.
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17.4.8. Error Detection and Handling
The LIN peripheral generates an interrupt request and stops the processing of the current frame if it
detects an error. The application has to check the type of error by processing the error register (LINERR).
After that, it has to reset the error register (LINERR) and the ERROR bit in status register (LINST) by writing a '1' to the RSTERR bit in the control register (LINCTRL). Starting a new message with the LIN peripheral selected as master or sending a Wakeup signal with the LIN peripheral selected as a master or slave
is possible only if ERROR bit in status register is set to '0'.
17.4.9. LIN Master Mode Operation
The operation setup of the LIN peripheral in Master mode requires that the LIN bus is not active (ACTIVE
bit in LINST register set to ‘0’).
The master is responsible for the schedule of the messages. It sends the header of each frame that contains SYNC BREAK FIELD, SYNC FIELD and IDENTIFIER FIELD. The steps for scheduling a message
frame are explained in the following paragraphs.
1. Load the 6-bit Identifier into the ID register (LINID).
2. Load the “data length” in the LINSIZE register (number of data bytes or value “1111b” if the data length
should be decoded from the identifier) and set the checksum type (classic or enhanced, defined by the
ENHCHK bit also in the LINSIZE register).
3. Adjust the TXRX bit (LINCTRL.5):
“1” - If the current frame is a transmit operation for the master.
“0” – If the current frame is a receive operation for the master.
4. Load the data bytes to transmit into the data buffer (LINDT1 to LINDT8 and transmit operation only).
5. The STREQ bit (LINCTRL) is set to start the message transfer. After that the LIN peripheral schedules
the message frame and request an interrupt if the message transfer is successfully completed or if an error
is occurred.
6. The following steps have to be performed by the application when an interrupt is requested.
6a. Check the DONE bit and the ERROR bit (LINST)
6b. Load the received data from the data buffer if the transfer was successful (for receive operation only).
6c. If the transfer was not successful, check the error register to determine the kind of error. Further error
handling has to be done by the application.
6d. Set the RSTINT and RSTERR bits in the status register (LINST) to reset the interrupt request and the
error flags.
17.4.10.LIN Slave Mode Operation
Once the Baud rate has been selected and the checksum type selected (classic or enhanced) the LIN
peripheral can start receiving messages.
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Access from application to data buffer and ID registers of the LIN core slave is possible when a data
request is pending (DTREQ bit in LINST register is ‘1’) and also when the LIN bus is not active (ACTIVE bit
in LINST register set to ‘0’).
The LIN peripheral in slave mode detects the header of the message frame sent by the LIN master. If slave
synchronization is enabled (autobaud), the slave synchronizes its internal bit time to the master bit time.
An interrupt is requested after the reception of the IDENTIFIER FIELD, when an error is detected or when
the message transfer is completed.
The following steps have to be done by the application when an interrupt is requested.
1. Check the DTREQ bit in the status register (LINST) is set.(set when the IDENTIFIER FIELD
has been received). If set then:
2. Load the identifier from the LINID register and process it
3. Adjust the TXRX bit in the control register (LINCTRL) (set to “1” if the current frame is a transmit operation for the slave and set to “0” if the current frame is a receive operation for the
slave)
4. Load the “data length” in the LINSIZE register (number of data bytes or value “1111b” if the
data length should be decoded from the identifier)
5. Load the data to transmit into the data buffer. (for transmit operation only)
6. Set the DTACK bit in the LINCTRL register.
Notes:
1. Steps 1a...1e have to be done during the IN-FRAME RESPONSE SPACE, if the current frame is a transmit
operation for the slave; otherwise a timeout will be detected by the master. If the current frame is a receive
operation for the slave, steps 1a...1e have to be finished until the reception of the first byte after the
IDENTIFIER FIELD. Otherwise, the internal receive buffer of the LIN peripheral will be overwritten and a
timeout error will be detected in the LIN peripheral.
2. If the application detects an unknown identifier (e.g. extended identifier) it has to write a ‘1’ to the STOP bit
(LINCTRL) instead of setting the DTACK bit (steps 1b...1e can then be skipped). In that case the LIN peripheral
stops the processing of the LIN communication until the next SYNC BREAK is received.
3. Changing the setup of the checksum (classic to enhanced or vice versa) during a transaction will cause the
interface to reset and the transaction to be lost. Therefore no change in the checksum should be performed
while there is a transaction in progress.
4. The same applies to changes in the LIN interface mode from slave mode to master mode and from master
mode to slave mode.
5. Check the DONE bit in the status register if the DTREQ bit is not set. The transmission was successful if the
DONE bit is set.
6. If the transmission was successful and the current frame was a receive operation for the slave, load the
received data bytes from the data buffer. Else check the error register (LINERR) to determine the kind of error.
Further error handling has to be done by the application.
7. Set the RSTINT and RSTERR bits in the status register (LINCTRL) to reset the interrupt request and the error
flags.
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NOTES:
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18. Enhanced Serial Peripheral Interface (SPI0)
The Serial Peripheral Interface (SPI0) provides access to a flexible, full-duplex synchronous serial bus.
SPI0 can operate as a master or slave device in both 3-wire or 4-wire modes, and supports multiple masters and slaves on a single SPI bus. The slave-select (NSS) signal can be configured as an input to select
SPI0 in slave mode, or to disable Master Mode operation in a multi-master environment, avoiding contention on the SPI bus when more than one master attempts simultaneous data transfers. NSS can also be
configured as a chip-select output in master mode, or disabled for 3-wire operation. Additional general purpose port I/O pins can be used to select multiple slave devices in master mode.
SFR Bus
SYSCLK
SPI0CN
SPIBSY
MSTEN
CKPHA
CKPOL
SLVSEL
NSSIN
SRMT
RXBMT
SPIF
WCOL
MODF
RXOVRN
NSSMD1
NSSMD0
TXBMT
SPIEN
SPI0CFG
SCR7
SCR6
SCR5
SCR4
SCR3
SCR2
SCR1
SCR0
SPI0CKR
Clock Divide
Logic
SPI CONTROL LOGIC
Data Path
Control
SPI IRQ
Pin Interface
Control
MOSI
Tx Data
SPI0DAT
SCK
Transmit Data Buffer
Shift Register
Rx Data
7 6 5 4 3 2 1 0
Receive Data Buffer
Pin
Control
Logic
MISO
C
R
O
S
S
B
A
R
Port I/O
NSS
Read
SPI0DAT
Write
SPI0DAT
SFR Bus
Figure 18.1. SPI Block Diagram
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18.1. Signal Descriptions
The four signals used by SPI0 (MOSI, MISO, SCK, NSS) are described below.
18.1.1. Master Out, Slave In (MOSI)
The master-out, slave-in (MOSI) signal is an output from a master device and an input to slave devices. It
is used to serially transfer data from the master to the slave. This signal is an output when SPI0 is operating as a master and an input when SPI0 is operating as a slave. Data is transferred most-significant bit
first. When configured as a master, MOSI is driven by the MSB of the shift register in both 3- and 4-wire
mode.
18.1.2. Master In, Slave Out (MISO)
The master-in, slave-out (MISO) signal is an output from a slave device and an input to the master device.
It is used to serially transfer data from the slave to the master. This signal is an input when SPI0 is operating as a master and an output when SPI0 is operating as a slave. Data is transferred most-significant bit
first. The MISO pin is placed in a high-impedance state when the SPI module is disabled and when the SPI
operates in 4-wire mode as a slave that is not selected. When acting as a slave in 3-wire mode, MISO is
always driven by the MSB of the shift register.
18.1.3. Serial Clock (SCK)
The serial clock (SCK) signal is an output from the master device and an input to slave devices. It is used
to synchronize the transfer of data between the master and slave on the MOSI and MISO lines. SPI0 generates this signal when operating as a master. The SCK signal is ignored by a SPI slave when the slave is
not selected (NSS = 1) in 4-wire slave mode.
18.1.4. Slave Select (NSS)
The function of the slave-select (NSS) signal is dependent on the setting of the NSSMD1 and NSSMD0
bits in the SPI0CN register. There are three possible modes that can be selected with these bits:
1. NSSMD[1:0] = 00: 3-Wire Master or 3-Wire Slave Mode: SPI0 operates in 3-wire mode, and
NSS is disabled. When operating as a slave device, SPI0 is always selected in 3-wire mode.
Since no select signal is present, SPI0 must be the only slave on the bus in 3-wire mode. This
is intended for point-to-point communication between a master and one slave.
2. NSSMD[1:0] = 01: 4-Wire Slave or Multi-Master Mode: SPI0 operates in 4-wire mode, and
NSS is enabled as an input. When operating as a slave, NSS selects the SPI0 device. When
operating as a master, a 1-to-0 transition of the NSS signal disables the master function of
SPI0 so that multiple master devices can be used on the same SPI bus.
3. NSSMD[1:0] = 1x: 4-Wire Master Mode: SPI0 operates in 4-wire mode, and NSS is enabled as
an output. The setting of NSSMD0 determines what logic level the NSS pin will output. This
configuration should only be used when operating SPI0 as a master device.
See Figure 18.2, Figure 18.3, and Figure 18.4 for typical connection diagrams of the various operational
modes. Note that the setting of NSSMD bits affects the pinout of the device. When in 3-wire master or
3-wire slave mode, the NSS pin will not be mapped by the crossbar. In all other modes, the NSS signal will
be mapped to a pin on the device. See Section “14. Port Input/Output” on page 117 for general purpose
port I/O and crossbar information.
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18.2. SPI0 Master Mode Operation
A SPI master device initiates all data transfers on a SPI bus. SPI0 is placed in master mode by setting the
Master Enable flag (MSTEN, SPI0CN.6). Writing a byte of data to the SPI0 data register (SPI0DAT) when
in master mode writes to the transmit buffer. If the SPI shift register is empty, the byte in the transmit buffer
is moved to the shift register, and a data transfer begins. The SPI0 master immediately shifts out the data
serially on the MOSI line while providing the serial clock on SCK. The SPIF (SPI0CN.7) flag is set to logic
1 at the end of the transfer. If interrupts are enabled, an interrupt request is generated when the SPIF flag
is set. While the SPI0 master transfers data to a slave on the MOSI line, the addressed SPI slave device
simultaneously transfers data to the SPI master on the MISO line in a full-duplex operation. Therefore, the
SPIF flag serves as both a transmit-complete and receive-data-ready flag. The data byte received from the
slave is transferred MSB-first into the master's shift register. When a byte is fully shifted into the register, it
is moved to the receive buffer where it can be read by the processor by reading SPI0DAT.
When configured as a master, SPI0 can operate in one of three different modes: multi-master mode, 3-wire
single-master mode, and 4-wire single-master mode. The default, multi-master mode is active when
NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 1. In this mode, NSS is an input to the device, and
is used to disable the master SPI0 when another master is accessing the bus. When NSS is pulled low in
this mode, MSTEN (SPI0CN.6) and SPIEN (SPI0CN.0) are set to 0 to disable the SPI master device, and
a Mode Fault is generated (MODF, SPI0CN.5 = 1). Mode Fault will generate an interrupt if enabled. SPI0
must be manually re-enabled in software under these circumstances. In multi-master systems, devices will
typically default to being slave devices while they are not acting as the system master device. In multi-master mode, slave devices can be addressed individually (if needed) using general-purpose I/O pins.
Figure 18.2 shows a connection diagram between two master devices in multiple-master mode.
3-wire single-master mode is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 0. In this
mode, NSS is not used and is not mapped to an external port pin through the crossbar. Any slave devices
that must be addressed in this mode should be selected using general-purpose I/O pins. Figure 18.3
shows a connection diagram between a master device in 3-wire master mode and a slave device.
4-wire single-master mode is active when NSSMD1 (SPI0CN.3) = 1. In this mode, NSS is configured as an
output pin and can be used as a slave-select signal for a single SPI device. In this mode, the output value
of NSS is controlled (in software) with the bit NSSMD0 (SPI0CN.2). Additional slave devices can be
addressed using general-purpose I/O pins. Figure 18.4 shows a connection diagram for a master device in
4-wire master mode and two slave devices.
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Master
Device 1
NSS
GPIO
MISO
MISO
MOSI
MOSI
SCK
SCK
GPIO
NSS
Master
Device 2
Figure 18.2. Multiple-Master Mode Connection Diagram
Master
Device
MISO
MISO
MOSI
MOSI
SCK
SCK
Slave
Device
Figure 18.3. 3-Wire Single Master and Slave Mode Connection Diagram
Master
Device
GPIO
MISO
MISO
MOSI
MOSI
SCK
SCK
NSS
NSS
MISO
MOSI
Slave
Device
Slave
Device
SCK
NSS
Figure 18.4. 4-Wire Single Master and Slave Mode Connection Diagram
18.3. SPI0 Slave Mode Operation
When SPI0 is enabled and not configured as a master, it will operate as a SPI slave. As a slave, bytes are
shifted in through the MOSI pin and out through the MISO pin by a master device controlling the SCK signal. A bit counter in the SPI0 logic counts SCK edges. When 8 bits have been shifted into the shift register,
the SPIF flag is set to logic 1, and the byte is copied into the receive buffer. Data is read from the receive
buffer by reading SPI0DAT. A slave device cannot initiate transfers. Data to be transferred to the master
device is pre-loaded into the shift register by writing to SPI0DAT. Writes to SPI0DAT are double-buffered,
and are placed in the transmit buffer first. If the shift register is empty, the contents of the transmit buffer
will immediately be transferred into the shift register. When the shift register already contains data, the SPI
will load the shift register with the transmit buffer’s contents after the last SCK edge of the next (or current)
SPI transfer.
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The shift register contents are locked after the slave detects the first edge of SCK. Writes to SPI0DAT that
occur after the first SCK edge will be held in the TX latch until the end of the current transfer.
When configured as a slave, SPI0 can be configured for 4-wire or 3-wire operation. The default, 4-wire
slave mode, is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 1. In 4-wire mode, the
NSS signal is routed to a port pin and configured as a digital input. SPI0 is enabled when NSS is logic 0,
and disabled when NSS is logic 1. The bit counter is reset on a falling edge of NSS. Note that the NSS signal must be driven low at least 2 system clocks before the first active edge of SCK for each byte transfer.
Figure 18.4 shows a connection diagram between two slave devices in 4-wire slave mode and a master
device.
3-wire slave mode is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 0. NSS is not
used in this mode, and is not mapped to an external port pin through the crossbar. Since there is not a way
of uniquely addressing the device in 3-wire slave mode, SPI0 must be the only slave device present on the
bus. It is important to note that in 3-wire slave mode there is no external means of resetting the bit counter
that determines when a full byte has been received. The bit counter can only be reset by disabling and reenabling SPI0 with the SPIEN bit. Figure 18.3 shows a connection diagram between a slave device in 3wire slave mode and a master device.
18.4. SPI0 Interrupt Sources
When SPI0 interrupts are enabled, the following four flags will generate an interrupt when they are set to
logic 1:
Note that all of the following interrupt bits must be cleared by software.
1. The SPI Interrupt Flag, SPIF (SPI0CN.7) is set to logic 1 at the end of each byte transfer. This
flag can occur in all SPI0 modes.
2. The Write Collision Flag, WCOL (SPI0CN.6) is set to logic 1 if a write to SPI0DAT is attempted
when the transmit buffer has not been emptied to the SPI shift register. When this occurs, the
write to SPI0DAT will be ignored, and the transmit buffer will not be written.This flag can occur
in all SPI0 modes.
3. The Mode Fault Flag MODF (SPI0CN.5) is set to logic 1 when SPI0 is configured as a master
in multi-master mode and the NSS pin is pulled low. When a Mode Fault occurs, the MSTEN
and SPIEN bits in SPI0CN are set to logic 0 to disable SPI0 and allow another master device
to access the bus.
4. The Receive Overrun Flag RXOVRN (SPI0CN.4) is set to logic 1 when configured as a slave,
and a transfer is completed while the receive buffer still holds an unread byte from a previous
transfer. The new byte is not transferred to the receive buffer, allowing the previously received
data byte to be read. The data byte which caused the overrun is lost.
18.5. Serial Clock Timing
Four combinations of serial clock phase and polarity can be selected using the clock control bits in the
SPI0 Configuration Register (SPI0CFG). The CKPHA bit (SPI0CFG.5) selects one of two clock phases
(edge used to latch the data). The CKPOL bit (SPI0CFG.4) selects between a rising edge or a falling edge.
Both master and slave devices must be configured to use the same clock phase and polarity. SPI0 should
be disabled (by clearing the SPIEN bit, SPI0CN.0) when changing the clock phase or polarity. The clock
and data line relationships are shown in Figure 18.5.
The SPI0 Clock Rate Register (SPI0CKR) as shown in SFR Definition 18.3 controls the master mode
serial clock frequency. This register is ignored when operating in slave mode. When the SPI is configured
as a master, the maximum data transfer rate (bits/sec) is one-half the system clock frequency or 12.5 MHz,
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whichever is slower. When the SPI is configured as a slave, the maximum data transfer rate (bits/sec) for
full-duplex operation is 1/10 the system clock frequency, provided that the master issues SCK, NSS (in 4wire slave mode), and the serial input data synchronously with the slave’s system clock. If the master
issues SCK, NSS, and the serial input data asynchronously, the maximum data transfer rate (bits/sec)
must be less than 1/10 the system clock frequency. In the special case where the master only wants to
transmit data to the slave and does not need to receive data from the slave (i.e. half-duplex operation), the
SPI slave can receive data at a maximum data transfer rate (bits/sec) of 1/4 the system clock frequency.
This is provided that the master issues SCK, NSS, and the serial input data synchronously with the slave’s
system clock.
SCK
(CKPOL=0, CKPHA=0)
SCK
(CKPOL=0, CKPHA=1)
SCK
(CKPOL=1, CKPHA=0)
SCK
(CKPOL=1, CKPHA=1)
MISO/MOSI
MSB
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Figure 18.5. Data/Clock Timing Relationship
18.6. SPI Special Function Registers
SPI0 is accessed and controlled through four special function registers in the system controller: SPI0CN
Control Register, SPI0DAT Data Register, SPI0CFG Configuration Register, and SPI0CKR Clock Rate
Register. The four special function registers related to the operation of the SPI0 Bus are described in the
following figures.
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SFR Definition 18.1. SPI0CFG: SPI0 Configuration
R
R/W
R/W
R/W
R
R
R
R
Reset Value
SPIBSY
MSTEN
CKPHA
CKPOL
SLVSEL
NSSIN
SRMT
RXBMT
00000111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xA1
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
SPIBSY: SPI Busy (read only).
This bit is set to logic 1 when a SPI transfer is in progress (Master or Slave Mode).
MSTEN: Master Mode Enable.
0: Disable master mode. Operate in slave mode.
1: Enable master mode. Operate as a master.
CKPHA: SPI0 Clock Phase.
This bit controls the SPI0 clock phase.
0: Data centered on first edge of SCK period.*
1: Data centered on second edge of SCK period.*
CKPOL: SPI0 Clock Polarity.
This bit controls the SPI0 clock polarity.
0: SCK line low in idle state.
1: SCK line high in idle state.
SLVSEL: Slave Selected Flag (read only).
This bit is set to logic 1 whenever the NSS pin is low indicating SPI0 is the selected slave. It
is cleared to logic 0 when NSS is high (slave not selected). This bit does not indicate the
instantaneous value at the NSS pin, but rather a de-glitched version of the pin input.
NSSIN: NSS Instantaneous Pin Input (read only).
This bit mimics the instantaneous value that is present on the NSS port pin at the time that
the register is read. This input is not de-glitched.
SRMT: Shift Register Empty (Valid in Slave Mode, read only).
This bit will be set to logic 1 when all data has been transferred in/out of the shift register,
and there is no new information available to read from the transmit buffer or write to the
receive buffer. It returns to logic 0 when a data byte is transferred to the shift register from
the transmit buffer or by a transition on SCK.
NOTE: SRMT = 1 when in Master Mode.
RXBMT: Receive Buffer Empty (Valid in Slave Mode, read only).
This bit will be set to logic 1 when the receive buffer has been read and contains no new
information. If there is new information available in the receive buffer that has not been read,
this bit will return to logic 0.
NOTE: RXBMT = 1 when in Master Mode.
*Note: See Table 18.1 for timing parameters.
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SFR Definition 18.2. SPI0CN: SPI0 Control
R/W
R/W
R/W
SPIF
WCOL
MODF
Bit7
Bit6
Bit5
R/W
R/W
R/W
RXOVRN NSSMD1 NSSMD0
Bit4
Bit3
Bit2
R
R/W
Reset Value
TXBMT
SPIEN
00000110
Bit1
Bit0
Bit
Addressable
SFR Address: 0xF8
Bit7:
SPIF: SPI0 Interrupt Flag.
This bit is set to logic 1 by hardware at the end of a data transfer. If interrupts are enabled,
setting this bit causes the CPU to vector to the SPI0 interrupt service routine. This bit is not
automatically cleared by hardware. It must be cleared by software.
Bit6:
WCOL: Write Collision Flag.
This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) to indicate a write to
the SPI0 data register was attempted while a data transfer was in progress. This bit is not
automatically cleared by hardware. It must be cleared by software.
Bit5:
MODF: Mode Fault Flag.
This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) when a master mode
collision is detected (NSS is low, MSTEN = 1, and NSSMD[1:0] = 01). This bit is not automatically cleared by hardware. It must be cleared by software.
Bit4:
RXOVRN: Receive Overrun Flag (Slave Mode only).
This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) when the receive
buffer still holds unread data from a previous transfer and the last bit of the current transfer is
shifted into the SPI0 shift register. This bit is not automatically cleared by hardware. It must
be cleared by software.
Bits3–2: NSSMD1–NSSMD0: Slave Select Mode.
Selects between the following NSS operation modes:
(See Section “18.2. SPI0 Master Mode Operation” on page 173 and Section “18.3. SPI0
Slave Mode Operation” on page 174).
00: 3-Wire Slave or 3-wire Master Mode. NSS signal is not routed to a port pin.
01: 4-Wire Slave or Multi-Master Mode (Default). NSS is always an input to the device.
1x: 4-Wire Single-Master Mode. NSS signal is mapped as an output from the device and will
assume the value of NSSMD0.
Bit1:
TXBMT: Transmit Buffer Empty.
This bit will be set to logic 0 when new data has been written to the transmit buffer. When
data in the transmit buffer is transferred to the SPI shift register, this bit will be set to logic 1,
indicating that it is safe to write a new byte to the transmit buffer.
Bit0:
SPIEN: SPI0 Enable.
This bit enables/disables the SPI.
0: SPI disabled.
1: SPI enabled.
178
Rev. 0.3
C8051F52x-53x
SFR Definition 18.3. SPI0CKR: SPI0 Clock Rate
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
SCR7
SCR6
SCR5
SCR4
SCR3
SCR2
SCR1
SCR0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xA2
Bits7–0: SCR7–SCR0: SPI0 Clock Rate.
These bits determine the frequency of the SCK output when the SPI0 module is configured
for master mode operation. The SCK clock frequency is a divided version of the system
clock, and is given in the following equation, where SYSCLK is the system clock frequency
and SPI0CKR is the 8-bit value held in the SPI0CKR register.
SYSCLK
f SCK = ------------------------------------------------2 × ( SPI0CKR + 1 )
for 0 <= SPI0CKR <= 255
Example: If SYSCLK = 2 MHz and SPI0CKR = 0x04,
2000000
f SCK = -------------------------2 × (4 + 1)
f SCK = 200kHz
Rev. 0.3
179
C8051F52x-53x
SFR Definition 18.4. SPI0DAT: SPI0 Data
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xA3
Bits7–0: SPI0DAT: SPI0 Transmit and Receive Data.
The SPI0DAT register is used to transmit and receive SPI0 data. Writing data to SPI0DAT
places the data into the transmit buffer and initiates a transfer when in Master Mode. A read
of SPI0DAT returns the contents of the receive buffer.
180
Rev. 0.3
C8051F52x-53x
SCK*
T
MCKH
T
MCKL
T
T
MIS
MIH
MISO
MOSI
* SCK is shown for CKPOL = 0. SCK is the opposite polarity for CKPOL = 1.
Figure 18.6. SPI Master Timing (CKPHA = 0)
SCK*
T
MCKH
T
MIS
T
MCKL
T
MIH
MISO
MOSI
* SCK is shown for CKPOL = 0. SCK is the opposite polarity for CKPOL = 1.
Figure 18.7. SPI Master Timing (CKPHA = 1)
Rev. 0.3
181
C8051F52x-53x
NSS
T
T
SE
T
CKL
SD
SCK*
T
CKH
T
SIS
T
SIH
MOSI
T
T
SEZ
T
SOH
SDZ
MISO
* SCK is shown for CKPOL = 0. SCK is the opposite polarity for CKPOL = 1.
Figure 18.8. SPI Slave Timing (CKPHA = 0)
NSS
T
T
SE
T
CKL
SD
SCK*
T
CKH
T
SIS
T
SIH
MOSI
T
SEZ
T
T
SOH
SDZ
MISO
* SCK is shown for CKPOL = 0. SCK is the opposite polarity for CKPOL = 1.
Figure 18.9. SPI Slave Timing (CKPHA = 1)
182
Rev. 0.3
C8051F52x-53x
Table 18.1. SPI Slave Timing Parameters
Parameter
Description
Min
Max
Units
Master Mode Timing* (See Figure 18.6 and Figure 18.7)
TMCKH
SCK High Time
1 x TSYSCLK
—
ns
TMCKL
SCK Low Time
1 x TSYSCLK
—
ns
TMIS
MISO Valid to SCK Sample Edge
20
—
ns
TMIH
SCK Sample Edge to MISO Change
0
—
ns
Slave Mode Timing* (See Figure 18.8 and Figure 18.9)
TSE
NSS Falling to First SCK Edge
2 x TSYSCLK
—
ns
TSD
Last SCK Edge to NSS Rising
2 x TSYSCLK
—
ns
TSEZ
NSS Falling to MISO Valid
—
4 x TSYSCLK
ns
TSDZ
NSS Rising to MISO High-Z
—
4 x TSYSCLK
ns
TCKH
SCK High Time
5 x TSYSCLK
—
ns
TCKL
SCK Low Time
5 x TSYSCLK
—
ns
TSIS
MOSI Valid to SCK Sample Edge
2 x TSYSCLK
—
ns
TSIH
SCK Sample Edge to MOSI Change
2 x TSYSCLK
—
ns
TSOH
SCK Shift Edge to MISO Change
—
4 x TSYSCLK
ns
*Note: TSYSCLK is equal to one period of the device system clock (SYSCLK) in ns.
The maximum possible frequency of the SPI can be calculated as:
Transmission: SYSCLK/2
Reception: SYSCLK/10
Rev. 0.3
183
C8051F52x-53x
NOTES:
184
Rev. 0.3
C8051F52x-53x
19. Timers
Each MCU includes three counter/timers: two are 16-bit counter/timers compatible with those found in the
standard 8051, and one is a 16-bit auto-reload timer for use with other device peripherals or for general
purpose use. These timers can be used to measure time intervals, count external events and generate
periodic interrupt requests. Timer 0 and Timer 1 are nearly identical and have four primary modes of operation. Timer 2 offer 16-bit and split 8-bit timer functionality with auto-reload.
Timer 0 and Timer 1 Modes:
13-bit counter/timer
16-bit counter/timer
8-bit counter/timer with auto-reload
Two 8-bit counter/timers
(Timer 0 only)
Timer 2 Modes:
16-bit timer with auto-reload
Two 8-bit timers with auto-reload
Timers 0 and 1 may be clocked by one of five sources, determined by the Timer Mode Select bits (T1M–
T0M) and the Clock Scale bits (SCA1–SCA0). The Clock Scale bits define a pre-scaled clock from which
Timer 0 and/or Timer 1 may be clocked (See SFR Definition 19.3 for pre-scaled clock selection).
Timer 0/1 may then be configured to use this pre-scaled clock signal or the system clock. Timer 2 may be
clocked by the system clock, the system clock divided by 12, or the external oscillator clock source divided
by 8.
Timer 0 and Timer 1 may also be operated as counters. When functioning as a counter, a counter/timer
register is incremented on each high-to-low transition at the selected input pin (T0 or T1). Events with a frequency of up to one-fourth the system clock's frequency can be counted. The input signal need not be periodic, but it must be held at a given level for at least two full system clock cycles to ensure the level is
properly sampled.
19.1. Timer 0 and Timer 1
Each timer is implemented as a 16-bit register accessed as two separate bytes: a low byte (TL0 or TL1)
and a high byte (TH0 or TH1). The Counter/Timer Control register (TCON) is used to enable Timer 0 and
Timer 1 as well as indicate status. Timer 0 interrupts can be enabled by setting the ET0 bit in the IE register
(Section “11.4. Interrupt Register Descriptions” on page 93); Timer 1 interrupts can be enabled by setting
the ET1 bit in the IE register (Section 11.4). Both counter/timers operate in one of four primary modes
selected by setting the Mode Select bits T1M1–T0M0 in the Counter/Timer Mode register (TMOD). Each
timer can be configured independently. Each operating mode is described below.
19.1.1. Mode 0: 13-bit Counter/Timer
Timer 0 and Timer 1 operate as 13-bit counter/timers in Mode 0. The following describes the configuration
and operation of Timer 0. However, both timers operate identically, and Timer 1 is configured in the same
manner as described for Timer 0.
The TH0 register holds the eight MSBs of the 13-bit counter/timer. TL0 holds the five LSBs in bit positions
TL0.4–TL0.0. The three upper bits of TL0 (TL0.7–TL0.5) are indeterminate and should be masked out or
ignored when reading. As the 13-bit timer register increments and overflows from 0x1FFF (all ones) to
0x0000, the timer overflow flag TF0 (TCON.5) is set and an interrupt will occur if Timer 0 interrupts are
enabled.
Rev. 0.3
185
C8051F52x-53x
The C/T0 bit (TMOD.2) selects the counter/timer's clock source. When C/T0 is set to logic 1, high-to-low
transitions at the selected Timer 0 input pin (T0) increment the timer register (Refer to Section
“14.1. Priority Crossbar Decoder” on page 119 for information on selecting and configuring external I/O
pins). Clearing C/T selects the clock defined by the T0M bit (CKCON.3). When T0M is set, Timer 0 is
clocked by the system clock. When T0M is cleared, Timer 0 is clocked by the source selected by the Clock
Scale bits in CKCON (see SFR Definition 19.3).
Setting the TR0 bit (TCON.4) enables the timer when either GATE0 (TMOD.3) is logic 0 or the input signal
/INT0 is active as defined by bit IN0PL in register IT01CF (see SFR Definition 11.5. IT01CF: INT0/INT1
Configuration). Setting GATE0 to ‘1’ allows the timer to be controlled by the external input signal /INT0 (see
Section “11.4. Interrupt Register Descriptions” on page 93), facilitating pulse width measurements.
TR0
0
1
1
1
GATE0
/INT0
X
X
0
X
1
0
1
1
X = Don't Care
Counter/Timer
Disabled
Enabled
Disabled
Enabled
Setting TR0 does not force the timer to reset. The timer registers should be loaded with the desired initial
value before the timer is enabled.
TL1 and TH1 form the 13-bit register for Timer 1 in the same manner as described above for TL0 and TH0.
Timer 1 is configured and controlled using the relevant TCON and TMOD bits just as with Timer 0. The
input signal /INT1 is used with Timer 1; the /INT1 polarity is defined by bit IN1PL in register IT01CF (see
SFR Definition 11.5. IT01CF: INT0/INT1 Configuration).
IT01CF
Figure 19.1. T0 Mode 0 Block Diagram
186
Rev. 0.3
C8051F52x-53x
19.1.2. Mode 1: 16-bit Counter/Timer
Mode 1 operation is the same as Mode 0, except that the counter/timer registers use all 16 bits. The
counter/timers are enabled and configured in Mode 1 in the same manner as for Mode 0.
19.1.3. Mode 2: 8-bit Counter/Timer with Auto-Reload
Mode 2 configures Timer 0 and Timer 1 to operate as 8-bit counter/timers with automatic reload of the start
value. TL0 holds the count and TH0 holds the reload value. When the counter in TL0 overflows from all
ones to 0x00, the timer overflow flag TF0 (TCON.5) is set and the counter in TL0 is reloaded from TH0. If
Timer 0 interrupts are enabled, an interrupt will occur when the TF0 flag is set. The reload value in TH0 is
not changed. TL0 must be initialized to the desired value before enabling the timer for the first count to be
correct. When in Mode 2, Timer 1 operates identically to Timer 0.
Both counter/timers are enabled and configured in Mode 2 in the same manner as Mode 0. Setting the
TR0 bit (TCON.4) enables the timer when either GATE0 (TMOD.3) is logic 0 or when the input signal /INT0
is active as defined by bit IN0PL in register IT01CF (see Section “11.5. External Interrupts” on page 97 for
details on the external input signals /INT0 and /INT1).
CKCON
TTTTSS
2 2 1 0 CC
MMMM A A
1 0
HL
Pre-scaled Clock
TMOD
G
A
T
E
1
C
/
T
1
T T G
1 1 A
MM T
1 0 E
0
C
/
T
0
INT01CF
T T
0 0
MM
1 0
I
N
1
P
L
I
N
1
S
L
2
I
N
1
S
L
1
I
N
1
S
L
0
I
N
0
P
L
I
N
0
S
L
2
I
N
0
S
L
1
I
N
0
S
L
0
0
0
SYSCLK
1
1
T0
TL0
(8 bits)
TCON
TCLK
TR0
Crossbar
GATE0
TH0
(8 bits)
/INT0
IN0PL
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
Interrupt
Reload
XOR
Figure 19.2. T0 Mode 2 Block Diagram
Rev. 0.3
187
C8051F52x-53x
19.1.4. Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)
In Mode 3, Timer 0 is configured as two separate 8-bit counter/timers held in TL0 and TH0. The
counter/timer in TL0 is controlled using the Timer 0 control/status bits in TCON and TMOD: TR0, C/T0,
GATE0 and TF0. TL0 can use either the system clock or an external input signal as its timebase. The TH0
register is restricted to a timer function sourced by the system clock or prescaled clock. TH0 is enabled
using the Timer 1 run control bit TR1. TH0 sets the Timer 1 overflow flag TF1 on overflow and thus controls
the Timer 1 interrupt.
Timer 1 is inactive in Mode 3. When Timer 0 is operating in Mode 3, Timer 1 can be operated in Modes 0,
1 or 2, but cannot be clocked by external signals nor set the TF1 flag and generate an interrupt. However,
the Timer 1 overflow can be used to generate baud rates for the SMBus and UART. While Timer 0 is operating in Mode 3, Timer 1 run control is handled through its mode settings. To run Timer 1 while Timer 0 is in
Mode 3, set the Timer 1 Mode as 0, 1, or 2. To disable Timer 1, configure it for Mode 3.
CKCON
TMOD
T T T T T TSS
3 3 2 2 1 0 CC
MMMMMM A A
HLHL
1 0
Pre-scaled Clock
G
A
T
E
1
C
/
T
1
T T
1 1
MM
1 0
G
A
T
E
0
C
/
T
0
T T
0 0
MM
1 0
0
TR1
1
0
TCON
SYSCLK
TH0
(8 bits)
1
T0
TL0
(8 bits)
TR0
Crossbar
/INT0
GATE0
IN0PL
XOR
Figure 19.3. T0 Mode 3 Block Diagram
188
Rev. 0.3
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
Interrupt
Interrupt
C8051F52x-53x
SFR Definition 19.1. TCON: Timer Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0x88
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
TF1: Timer 1 Overflow Flag.
Set by hardware when Timer 1 overflows. This flag can be cleared by software but is automatically cleared when the CPU vectors to the Timer 1 interrupt service routine.
0: No Timer 1 overflow detected.
1: Timer 1 has overflowed.
TR1: Timer 1 Run Control.
0: Timer 1 disabled.
1: Timer 1 enabled.
TF0: Timer 0 Overflow Flag.
Set by hardware when Timer 0 overflows. This flag can be cleared by software but is automatically cleared when the CPU vectors to the Timer 0 interrupt service routine.
0: No Timer 0 overflow detected.
1: Timer 0 has overflowed.
TR0: Timer 0 Run Control.
0: Timer 0 disabled.
1: Timer 0 enabled.
IE1: External Interrupt 1.
This flag is set by hardware when an edge/level of type defined by IT1 is detected. It can be
cleared by software but is automatically cleared when the CPU vectors to the External Interrupt 1 service routine if IT1 = 1. When IT1 = 0, this flag is set to ‘1’ when /INT1 is active as
defined by bit IN1PL in register IT01CF (see SFR Definition 11.5. “IT01CF: INT0/INT1 Configuration” on page 98).
IT1: Interrupt 1 Type Select.
This bit selects whether the configured /INT1 interrupt will be edge or level sensitive. /INT1
is configured active low or high by the IN1PL bit in the IT01CF register (see SFR
Definition 11.5. “IT01CF: INT0/INT1 Configuration” on page 98).
0: /INT1 is level triggered.
1: /INT1 is edge triggered.
IE0: External Interrupt 0.
This flag is set by hardware when an edge/level of type defined by IT0 is detected. It can be
cleared by software but is automatically cleared when the CPU vectors to the External Interrupt 0 service routine if IT0 = 1. When IT0 = 0, this flag is set to ‘1’ when /INT0 is active as
defined by bit IN0PL in register IT01CF (see SFR Definition 11.5. “IT01CF: INT0/INT1 Configuration” on page 98).
IT0: Interrupt 0 Type Select.
This bit selects whether the configured /INT0 interrupt will be edge or level sensitive. /INT0
is configured active low or high by the IN0PL bit in register IT01CF (see SFR
Definition 11.5. “IT01CF: INT0/INT1 Configuration” on page 98).
0: /INT0 is level triggered.
1: /INT0 is edge triggered.
Rev. 0.3
189
C8051F52x-53x
SFR Definition 19.2. TMOD: Timer Mode
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
GATE1
C/T1
T1M1
T1M0
GATE0
C/T0
T0M1
T0M0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x89
Bit7:
GATE1: Timer 1 Gate Control.
0: Timer 1 enabled when TR1 = 1 irrespective of /INT1 logic level.
1: Timer 1 enabled only when TR1 = 1 AND /INT1 is active as defined by bit IN1PL in register IT01CF (see SFR Definition 11.5. “IT01CF: INT0/INT1 Configuration” on page 98).
Bit6:
C/T1: Counter/Timer 1 Select.
0: Timer Function: Timer 1 incremented by clock defined by T1M bit (CKCON.4).
1: Counter Function: Timer 1 incremented by high-to-low transitions on external input pin
(T1).
Bits5–4: T1M1–T1M0: Timer 1 Mode Select.
These bits select the Timer 1 operation mode.
T1M1
0
0
1
1
T1M0
0
1
0
1
Mode
Mode 0: 13-bit counter/timer
Mode 1: 16-bit counter/timer
Mode 2: 8-bit counter/timer with auto-reload
Mode 3: Timer 1 inactive
Bit3:
GATE0: Timer 0 Gate Control.
0: Timer 0 enabled when TR0 = 1 irrespective of /INT0 logic level.
1: Timer 0 enabled only when TR0 = 1 AND /INT0 is active as defined by bit IN0PL in register IT01CF (see SFR Definition 11.5. “IT01CF: INT0/INT1 Configuration” on page 98).
Bit2:
C/T0: Counter/Timer Select.
0: Timer Function: Timer 0 incremented by clock defined by T0M bit (CKCON.3).
1: Counter Function: Timer 0 incremented by high-to-low transitions on external input pin
(T0).
Bits1–0: T0M1–T0M0: Timer 0 Mode Select.
These bits select the Timer 0 operation mode.
T0M1
0
0
1
1
190
T0M0
0
1
0
1
Mode
Mode 0: 13-bit counter/timer
Mode 1: 16-bit counter/timer
Mode 2: 8-bit counter/timer with auto-reload
Mode 3: Two 8-bit counter/timers
Rev. 0.3
C8051F52x-53x
SFR Definition 19.3. CKCON: Clock Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
—
—
T2MH
T2ML
T1M
T0M
SCA1
SCA0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x8E
Bit7–6:
Bit5:
RESERVED. Read = 0b; Must write 0b.
T2MH: Timer 2 High Byte Clock Select.
This bit selects the clock supplied to the Timer 2 high byte if Timer 2 is configured in split 8bit timer mode. T2MH is ignored if Timer 2 is in any other mode.
0: Timer 2 high byte uses the clock defined by the T2XCLK bit in TMR2CN.
1: Timer 2 high byte uses the system clock.
Bit4:
T2ML: Timer 2 Low Byte Clock Select.
This bit selects the clock supplied to Timer 2. If Timer 2 is configured in split 8-bit timer
mode, this bit selects the clock supplied to the lower 8-bit timer.
0: Timer 2 low byte uses the clock defined by the T2XCLK bit in TMR2CN.
1: Timer 2 low byte uses the system clock.
Bit3:
T1M: Timer 1 Clock Select.
This select the clock source supplied to Timer 1. T1M is ignored when C/T1 is set to logic 1.
0: Timer 1 uses the clock defined by the prescale bits, SCA1–SCA0.
1: Timer 1 uses the system clock.
Bit2:
T0M: Timer 0 Clock Select.
This bit selects the clock source supplied to Timer 0. T0M is ignored when C/T0 is set to
logic 1.
0: Counter/Timer 0 uses the clock defined by the prescale bits, SCA1–SCA0.
1: Counter/Timer 0 uses the system clock.
Bits1–0: SCA1–SCA0: Timer 0/1 Prescale Bits.
These bits control the division of the clock supplied to Timer 0 and Timer 1 if configured to
use prescaled clock inputs.
SCA1
SCA0
Prescaled Clock
0
0
System clock divided by 12
0
1
System clock divided by 4
1
0
System clock divided by 48
1
1
External clock divided by 8
Note: External clock divided by 8 is synchronized with
the system clock.
Rev. 0.3
191
C8051F52x-53x
SFR Definition 19.4. TL0: Timer 0 Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0x8A
Bits 7–0: TL0: Timer 0 Low Byte.
The TL0 register is the low byte of the 16-bit Timer 0.
SFR Definition 19.5. TL1: Timer 1 Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0x8B
Bits 7–0: TL1: Timer 1 Low Byte.
The TL1 register is the low byte of the 16-bit Timer 1.
SFR Definition 19.6. TH0: Timer 0 High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x8C
Bits 7–0: TH0: Timer 0 High Byte.
The TH0 register is the high byte of the 16-bit Timer 0.
SFR Definition 19.7. TH1: Timer 1 High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x8D
Bits 7–0: TH1: Timer 1 High Byte.
The TH1 register is the high byte of the 16-bit Timer 1.
192
Rev. 0.3
C8051F52x-53x
19.2. Timer 2
Timer 2 is a 16-bit timer formed by two 8-bit SFRs: TMR2L (low byte) and TMR2H (high byte). Timer 2 may
operate in 16-bit auto-reload mode or (split) 8-bit auto-reload mode. The T2SPLIT bit (TMR2CN.3) defines
the Timer 2 operation mode. Timer 2 can also be used in Capture Mode to measure the RTC0 clock frequency or the External Oscillator clock frequency.
Timer 2 may be clocked by the system clock, the system clock divided by 12, or the external oscillator
source divided by 8. The external oscillator source divided by 8 is synchronized with the system clock.
19.2.1. 16-bit Timer with Auto-Reload
When T2SPLIT (TMR2CN.3) is zero, Timer 2 operates as a 16-bit timer with auto-reload. Timer 2 can be
clocked by SYSCLK, SYSCLK divided by 12, or the external oscillator clock source divided by 8. As the
16-bit timer register increments and overflows from 0xFFFF to 0x0000, the 16-bit value in the Timer 2
reload registers (TMR2RLH and TMR2RLL) is loaded into the Timer 2 register as shown in Figure 19.4,
and the Timer 2 High Byte Overflow Flag (TMR2CN.7) is set. If Timer 2 interrupts are enabled (if IE.5 is
set), an interrupt will be generated on each Timer 2 overflow. Additionally, if Timer 2 interrupts are enabled
and the TF2LEN bit is set (TMR2CN.5), an interrupt will be generated each time the lower 8 bits (TMR2L)
overflow from 0xFF to 0x00.
CKCON
TTTTTTSS
3 3 2 2 1 0CC
T2XCLK M M M M M M A A
HLHL
1 0
0
TMR2L
Overflow
0
External Clock / 8
SYSCLK
TR2
1
TCLK
TMR2L
TMR2H
TMR2CN
SYSCLK / 12
1
TF2H
TF2L
TF2LEN
Interrupt
T2SPLIT
TR2
T2XCLK
TMR2RLL TMR2RLH
Reload
Figure 19.4. Timer 2 16-Bit Mode Block Diagram
Rev. 0.3
193
C8051F52x-53x
19.2.2. 8-bit Timers with Auto-Reload
When T2SPLIT is set, Timer 2 operates as two 8-bit timers (TMR2H and TMR2L). Both 8-bit timers operate in auto-reload mode as shown in Figure 19.5. TMR2RLL holds the reload value for TMR2L; TMR2RLH
holds the reload value for TMR2H. The TR2 bit in TMR2CN handles the run control for TMR2H. TMR2L is
always running when configured for 8-bit Mode.
Each 8-bit timer may be configured to use SYSCLK, SYSCLK divided by 12, or the external oscillator clock
source divided by 8. The Timer 2 Clock Select bits (T2MH and T2ML in CKCON) select either SYSCLK or
the clock defined by the Timer 2 External Clock Select bit (T2XCLK in TMR2CN), as follows:
T2MH
0
0
1
T2XCLK TMR2H Clock Source
0
SYSCLK / 12
1
External Clock / 8
X
SYSCLK
T2ML
0
0
1
T2XCLK
0
1
X
TMR2L Clock Source
SYSCLK / 12
External Clock / 8
SYSCLK
The TF2H bit is set when TMR2H overflows from 0xFF to 0x00; the TF2L bit is set when TMR2L overflows
from 0xFF to 0x00. When Timer 2 interrupts are enabled (IE.5), an interrupt is generated each time
TMR2H overflows. If Timer 2 interrupts are enabled and TF2LEN (TMR2CN.5) is set, an interrupt is generated each time either TMR2L or TMR2H overflows. When TF2LEN is enabled, software must check the
TF2H and TF2L flags to determine the source of the Timer 2 interrupt. The TF2H and TF2L interrupt flags
are not cleared by hardware and must be manually cleared by software.
CKCON
T T T T T T S
3 3 2 2 1 0 C
MMMMMMA
H L H L
1
T2XCLK
SYSCLK / 12
0
External Clock / 8
1
S
C
A
0
TMR2RLH
Reload
0
TCLK
TR2
TMR2H
TMR2RLL
SYSCLK
Reload
TMR2CN
1
TF2H
TF2L
TF2LEN
T2SPLIT
TR2
T2XCLK
1
TCLK
TMR2L
0
Figure 19.5. Timer 2 8-Bit Mode Block Diagram
194
Rev. 0.3
Interrupt
C8051F52x-53x
19.2.3. External Capture Mode
Capture Mode allows either the external oscillator to be measured against the system clock. The external
oscillator clock can also be compared against each other. Timer 2 can be clocked from the system clock,
the system clock divided by 12, the external oscillator divided by 8, depending on the T2ML (CKCON.4),
T2XCLK, and T2RCLK settings. The timer will capture either every 8 eternal clock cycles, depending on
the T2RCLK setting. When a capture event is generated, the contents of Timer 2 (TMR2H:TMR2L) are
loaded into the Timer 2 reload registers (TMR2RLH:TMR2RLL) and the TF2H flag is set. By recording the
difference between two successive timer capture values, the external oscillator can be determined with
respect to the Timer 2 clock. The Timer 2 clock should be much faster than the capture clock to achieve an
accurate reading. Timer 2 should be in 16-bit auto-reload mode when using Capture Mode.
CKCON
T T T T T T S
3 3 2 2 1 0 C
MMMMMM A
H L H L
1
S
C
A
0
T2XCLK
SYSCLK
1
1
TR2
0
SYSCLK / 12
TCLK
TMR2H
TMR2L
Capture
0
TMR2RLH TMR2RLL
TMR2CN
External Osc. / 8
TF2H
TF2L
TF2LEN
TF2CEN
Interrupt
TR2
TR2CLK
T2XCLK
External Osc. / 8
TF2CEN
Figure 19.6. Timer 2 Capture Mode Block Diagram
Rev. 0.3
195
C8051F52x-53x
SFR Definition 19.8. TMR2CN: Timer 2 Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
TF2H
TF2L
TF2LEN
TF2CEN
T2SPLIT
TR2
T2RCLK
T2XCLK
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xC8
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
196
TF2H: Timer 2 High Byte Overflow Flag.
Set by hardware when the Timer 2 high byte overflows from 0xFF to 0x00. In 16 bit mode,
this will occur when Timer 2 overflows from 0xFFFF to 0x0000. When the Timer 2 interrupt is
enabled, setting this bit causes the CPU to vector to the Timer 2 interrupt service routine.
TF2H is not automatically cleared by hardware and must be cleared by software.
TF2L: Timer 2 Low Byte Overflow Flag.
Set by hardware when the Timer 2 low byte overflows from 0xFF to 0x00. When this bit is
set, an interrupt will be generated if TF2LEN is set and Timer 2 interrupts are enabled. TF2L
will set when the low byte overflows regardless of the Timer 2 mode. This bit is not automatically cleared by hardware.
TF2LEN: Timer 2 Low Byte Interrupt Enable.
This bit enables/disables Timer 2 Low Byte interrupts. If TF2LEN is set and Timer 2 interrupts are enabled, an interrupt will be generated when the low byte of Timer 2 overflows.
This bit should be cleared when operating Timer 2 in 16-bit mode.
0: Timer 2 Low Byte interrupts disabled.
1: Timer 2 Low Byte interrupts enabled.
TF2CEN. Timer 2 Capture Enable.
0: Timer 2 capture mode disabled.
1: Timer 2 capture mode enabled.
T2SPLIT: Timer 2 Split Mode Enable.
When this bit is set, Timer 2 operates as two 8-bit timers with auto-reload.
0: Timer 2 operates in 16-bit auto-reload mode.
1: Timer 2 operates as two 8-bit auto-reload timers.
TR2: Timer 2 Run Control.
This bit enables/disables Timer 2. In 8-bit mode, this bit enables/disables TMR2H only;
TMR2L is always enabled in this mode.
0: Timer 2 disabled.
1: Timer 2 enabled.
T2RCLK: Timer 2 Capture Mode.
This bit controls the Timer 2 capture source when TF2CEN=1. If T2XCLK = 1 and T2ML
(CKCON.4) = 0, this bit also controls the clock source for Timer 2.
0: Capture every RTC clock/8. If T2XCLK = 1 and T2ML (CKCON.4) = 0, count at external
oscillator/8.
1: Capture every external oscillator/8. If T2XCLK = 1 and T2ML (CKCON.4) = 0, count at
RTC0 clock/8.
T2XCLK: Timer 2 External Clock Select.
This bit selects the external clock source for Timer 2. If Timer 2 is in 8-bit mode, this bit
selects the external oscillator clock source for both timer bytes. However, the Timer 2 Clock
Select bits (T2MH and T2ML in register CKCON) may still be used to select between the
external clock and the system clock for either timer.
0: Timer 2 external clock selection is the system clock divided by 12.
1: Timer 2 external clock uses the clock defined by the T2RCLK bit.
Rev. 0.3
C8051F52x-53x
SFR Definition 19.9. TMR2RLL: Timer 2 Reload Register Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xCA
Bits7–0: TMR2RLL: Timer 2 Reload Register Low Byte.
TMR2RLL holds the low byte of the reload value for Timer 2.
SFR Definition 19.10. TMR2RLH: Timer 2 Reload Register High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0xCB
Bits7–0: TMR2RLH: Timer 2 Reload Register High Byte.
The TMR2RLH holds the high byte of the reload value for Timer 2.
SFR Definition 19.11. TMR2L: Timer 2 Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xCC
Bits7–0: TMR2L: Timer 2 Low Byte.
In 16-bit mode, the TMR2L register contains the low byte of the 16-bit Timer 2. In 8-bit mode,
TMR2L contains the 8-bit low byte timer value.
SFR Definition 19.12. TMR2H Timer 2 High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xCD
Bits7–0: TMR2H: Timer 2 High Byte.
In 16-bit mode, the TMR2H register contains the high byte of the 16-bit Timer 2. In 8-bit
mode, TMR2H contains the 8-bit high byte timer value.
Rev. 0.3
197
C8051F52x-53x
NOTES:
198
Rev. 0.3
C8051F52x-53x
20. Programmable Counter Array (PCA0)
The Programmable Counter Array (PCA0) provides enhanced timer functionality while requiring less CPU
intervention than the standard 8051 counter/timers. The PCA consists of a dedicated 16-bit counter/timer
and three 16-bit capture/compare modules. Each capture/compare module has its own associated I/O line
(CEXn) which is routed through the Crossbar to Port I/O when enabled (See Section “14.1. Priority Crossbar Decoder” on page 119 for details on configuring the Crossbar). The counter/timer is driven by a programmable timebase that can select between six sources: system clock, system clock divided by four,
system clock divided by twelve, the external oscillator clock source divided by 8, Timer 0 overflow, or an
external clock signal on the ECI input pin. Each capture/compare module may be configured to operate
independently in one of three modes: Edge-Triggered Capture, Software Timer, High-Speed Output, Frequency Output, 8-Bit PWM, or 16-Bit PWM (each mode is described in Section “20.2. Capture/Compare
Modules” on page 201). The PCA is configured and controlled through the system controller's Special
Function Registers. The PCA block diagram is shown in Figure 20.1
Important Note: The PCA Module 2 may be used as a watchdog timer (WDT), and is enabled in this mode
following a system reset. Access to certain PCA registers is restricted while WDT mode is enabled.
See Section “20.3. Watchdog Timer Mode” on page 207 for details.
SYSCLK/12
SYSCLK/4
Timer 0 Overflow
ECI
SYSCLK
PCA
CLOCK
MUX
16-Bit Counter/Timer
External Clock/8
Capture/Compare
Module 0
Capture/Compare
Module 1
Capture/Compare
Module 2
CEX2
CEX1
CEX0
ECI
Crossbar
Port I/O
Figure 20.1. PCA Block Diagram
Rev. 0.3
199
C8051F52x-53x
20.1. PCA Counter/Timer
The 16-bit PCA counter/timer consists of two 8-bit SFRs: PCA0L and PCA0H. PCA0H is the high byte
(MSB) of the 16-bit counter/timer and PCA0L is the low byte (LSB). Reading PCA0L automatically latches
the value of PCA0H into a “snapshot” register; the following PCA0H read accesses this “snapshot” register.
Reading the PCA0L Register first guarantees an accurate reading of the entire 16-bit PCA0 counter.
Reading PCA0H or PCA0L does not disturb the counter operation. The CPS2-CPS0 bits in the PCA0MD
register select the timebase for the counter/timer as shown in Table 20.1.
When the counter/timer overflows from 0xFFFF to 0x0000, the Counter Overflow Flag (CF) in PCA0MD is
set to logic 1 and an interrupt request is generated if CF interrupts are enabled. Setting the ECF bit in
PCA0MD to logic 1 enables the CF flag to generate an interrupt request. The CF bit is not automatically
cleared by hardware when the CPU vectors to the interrupt service routine, and must be cleared by software (Note: PCA0 interrupts must be globally enabled before CF interrupts are recognized. PCA0 interrupts
are globally enabled by setting the EA bit (IE.7) and the EPCA0 bit in EIE1 to logic 1). Clearing the CIDL bit
in the PCA0MD register allows the PCA to continue normal operation while the CPU is in Idle mode.
Table 20.1. PCA Timebase Input Options
CPS2
0
0
0
0
1
1
1
CPS1
0
0
1
1
0
0
1
CPS0
0
1
0
1
0
1
0
Timebase
System clock divided by 12
System clock divided by 4
Timer 0 overflow
High-to-low transitions on ECI (max rate = system clock divided by 4)
System clock
External oscillator source divided by 8*
RTC clock divided by 8*
*Note: External clock divided by 8 and RTC0 clock divided by 8 are synchronized with the system clock.
IDLE
PCA0MD
C
I
D
L
WW
D D
T L
E C
K
C
P
S
2
C
P
S
1
CE
PC
S F
0
PCA0CN
CC
FR
C
C
F
2
C
C
F
1
C
C
F
0
To SFR Bus
PCA0L
read
Snapshot
Register
SYSCLK/12
SYSCLK/4
Timer 0 Overflow
ECI
SYSCLK
External Clock/8
000
001
010
011
0
1
PCA0H
PCA0L
Overflow
CF
100
To PCA Modules
101
Figure 20.2. PCA Counter/Timer Block Diagram
200
To PCA Interrupt System
Rev. 0.3
C8051F52x-53x
20.2. Capture/Compare Modules
Each module can be configured to operate independently in one of six operation modes: Edge-triggered
Capture, Software Timer, High Speed Output, Frequency Output, 8-Bit Pulse Width Modulator, or 16-Bit
Pulse Width Modulator. Each module has Special Function Registers (SFRs) associated with it in the CIP51 system controller. These registers are used to exchange data with a module and configure the module's
mode of operation.
Table 20.2 summarizes the bit settings in the PCA0CPMn registers used to select the PCA capture/compare module’s operating modes. Setting the ECCFn bit in a PCA0CPMn register enables the module's
CCFn interrupt. Note: PCA0 interrupts must be globally enabled before individual CCFn interrupts are recognized. PCA0 interrupts are globally enabled by setting the EA bit and the EPCA0 bit to logic 1. See
Figure 20.3 for details on the PCA interrupt configuration.
Table 20.2. PCA0CPM Register Settings for PCA Capture/Compare Modules
PWM16 ECOM CAPP CAPN
MAT
TOG
PWM ECCF
X
X
1
0
0
0
0
X
X
X
0
1
0
0
0
X
X
X
1
1
0
0
0
X
0
0
0
0
0
0
0
0
0
0
1
1
X
X
X
0
1
1
0
0
0
0
1
1
1
X
X
X
X
X
X
1
X
1
X
1
0
1
1
1
X = Don’t Care
Operation Mode
Capture triggered by positive edge on
CEXn
Capture triggered by negative edge on
CEXn
Capture triggered by transition on
CEXn
Software Timer
High Speed Output
Frequency Output
8-Bit Pulse Width Modulator
16-Bit Pulse Width Modulator
(for n = 0 to 5)
PCA0CPMn
P ECCMT P E
WC A A A OWC
MOPP TGMC
1 MP N n n n F
n
6 n n n
n
PCA0CN
CC
FR
CCC
CCC
FFF
2 1 0
PCA0MD
C
I
D
L
CCCE
PPPC
SSSF
2 1 0
0
PCA Counter/
Timer Overflow
1
EPCA0
(EIE1.4)
ECCF0
PCA Module 0
(CCF0)
0
0
1
1
EA
(IE.7)
0
1
Interrupt
Priority
Decoder
ECCF1
0
PCA Module 1
(CCF1)
1
ECCF2
PCA Module 2
(CCF2)
0
1
Figure 20.3. PCA Interrupt Block Diagram
Rev. 0.3
201
C8051F52x-53x
20.2.1. Edge-triggered Capture Mode
In this mode, a valid transition on the CEXn pin causes the PCA to capture the value of the PCA
counter/timer and load it into the corresponding module's 16-bit capture/compare register (PCA0CPLn and
PCA0CPHn). The CAPPn and CAPNn bits in the PCA0CPMn register are used to select the type of transition that triggers the capture: low-to-high transition (positive edge), high-to-low transition (negative edge),
or either transition (positive or negative edge). When a capture occurs, the Capture/Compare Flag (CCFn)
in PCA0CN is set to logic 1 and an interrupt request is generated if CCF interrupts are enabled. The CCFn
bit is not automatically cleared by hardware when the CPU vectors to the interrupt service routine, and
must be cleared by software. If both CAPPn and CAPNn bits are set to logic 1, then the state of the Port
pin associated with CEXn can be read directly to determine whether a rising-edge or falling-edge caused
the capture.
PCA Interrupt
PCA0CPMn
0
Port I/O
Crossbar
CEXn
PCA0CN
CC
FR
CCC
CCC
FFF
2 1 0
(to CCFn)
P ECCMT P E
WC A A AOWC
MOPP TGMC
1 MP N n n n F
6 n n n
n
n
1
PCA0CPLn
PCA0CPHn
Capture
0
1
PCA
Timebase
PCA0L
PCA0H
Figure 20.4. PCA Capture Mode Diagram
Note: The CEXn input signal must remain high or low for at least 2 system clock cycles to be recognized
by the hardware.
202
Rev. 0.3
C8051F52x-53x
20.2.2. Software Timer (Compare) Mode
In Software Timer mode, the PCA counter/timer value is compared to the module's 16-bit capture/compare
register (PCA0CPHn and PCA0CPLn). When a match occurs, the Capture/Compare Flag (CCFn) in
PCA0CN is set to logic 1 and an interrupt request is generated if CCF interrupts are enabled. The CCFn bit
is not automatically cleared by hardware when the CPU vectors to the interrupt service routine, and must
be cleared by software. Setting the ECOMn and MATn bits in the PCA0CPMn register enables Software
Timer mode.
Important Note About Capture/Compare Registers: When writing a 16-bit value to the PCA0 Capture/Compare registers, the low byte should always be written first. Writing to PCA0CPLn clears the
ECOMn bit to ‘0’; writing to PCA0CPHn sets ECOMn to ‘1’.
Write to
PCA0CPLn
0
ENB
Reset
Write to
PCA0CPHn
PCA
Interrupt
ENB
1
PCA0CPMn
PCA0CN
P ECCMT P E
WC A A AOWC
MOPP TGMC
1 MP N n n n F
6 n n n
n
n
x
0 0
PCA0CPLn
CC
FR
PCA0CPHn
CCC
CCC
FFF
2 1 0
0 0 x
Enable
16-bit Comparator
PCA
Timebase
PCA0L
Match
0
1
PCA0H
Figure 20.5. PCA Software Timer Mode Diagram
Rev. 0.3
203
C8051F52x-53x
20.2.3. High Speed Output Mode
In High Speed Output mode, a module’s associated CEXn pin is toggled each time a match occurs
between the PCA Counter and the module's 16-bit capture/compare register (PCA0CPHn and
PCA0CPLn) Setting the TOGn, MATn, and ECOMn bits in the PCA0CPMn register enables the HighSpeed Output mode.
Important Note About Capture/Compare Registers: When writing a 16-bit value to the PCA0 Capture/Compare registers, the low byte should always be written first. Writing to PCA0CPLn clears the
ECOMn bit to ‘0’; writing to PCA0CPHn sets ECOMn to ‘1’.
Write to
PCA0CPLn
0
ENB
Reset
Write to
PCA0CPHn
PCA0CPMn
P ECCMT P E
WC A A AOWC
MOPP TGMC
1 MP N n n n F
6 n n n
n
n
ENB
1
x
0 0
PCA
Interrupt
0 x
PCA0CN
PCA0CPLn
Enable
CC
FR
PCA0CPHn
16-bit Comparator
Match
0
1
Toggle
PCA
Timebase
CCC
CCC
FFF
2 1 0
TOGn
0 CEXn
1
PCA0L
Crossbar
Port I/O
PCA0H
Figure 20.6. PCA High-Speed Output Mode Diagram
Note: The initial state of the Toggle output is logic 1 and is initialized to this state when the module enters
High Speed Output Mode.
204
Rev. 0.3
C8051F52x-53x
20.2.4. Frequency Output Mode
Frequency Output Mode produces a programmable-frequency square wave on the module’s associated
CEXn pin. The capture/compare module high byte holds the number of PCA clocks to count before the output is toggled. The frequency of the square wave is then defined by Equation 20.1.
F PCA
F CEXn = ----------------------------------------2 × PCA0CPHn
Note: A value of 0x00 in the PCA0CPHn register is equal to 256 for this equation.
Equation 20.1. Square Wave Frequency Output
Where FPCA is the frequency of the clock selected by the CPS2-0 bits in the PCA mode register, PCA0MD.
The lower byte of the capture/compare module is compared to the PCA counter low byte; on a match,
CEXn is toggled and the offset held in the high byte is added to the matched value in PCA0CPLn. Frequency Output Mode is enabled by setting the ECOMn, TOGn, and PWMn bits in the PCA0CPMn register.
PCA0CPMn
P ECCMT P E
WC A A AOWC
MOPP TGMC
1 MP N n n n F
6 n n n
n
n
0
0 0 0 1
PCA0CPLn
8-bit Adder
Adder
Enable
Toggle
0
Enable
PCA Timebase
8-bit
Comparator
match
PCA0CPHn
TOGn
0 CEXn
1
Crossbar
Port I/O
PCA0L
Figure 20.7. PCA Frequency Output Mode
Rev. 0.3
205
C8051F52x-53x
20.2.5. 8-Bit Pulse Width Modulator Mode
Each module can be used independently to generate a pulse width modulated (PWM) output on its associated CEXn pin. The frequency of the output is dependent on the timebase for the PCA counter/timer. The
duty cycle of the PWM output signal is varied using the module's PCA0CPHn capture/compare register.
When the value in the low byte of the PCA counter/timer (PCA0L) is equal to the value in PCA0CPLn, the
output on the CEXn pin will be set. When the count value in PCA0L overflows, the CEXn output will be
reset (see Figure 20.8). Also, when the counter/timer low byte (PCA0L) overflows from 0xFF to 0x00,
PCA0CPLn is reloaded automatically with the value stored in the module’s capture/compare high byte
(PCA0CPHn) without software intervention. Setting the ECOMn and PWMn bits in the PCA0CPMn register
enables 8-Bit Pulse Width Modulator mode. The duty cycle for 8-Bit PWM Mode is given by Equation 20.2.
Important Note About Capture/Compare Registers: When writing a 16-bit value to the PCA0 Capture/Compare registers, the low byte should always be written first. Writing to PCA0CPLn clears the
ECOMn bit to ‘0’; writing to PCA0CPHn sets ECOMn to ‘1’.
( 256 – PCA0CPHn )
DutyCycle = --------------------------------------------------256
Equation 20.2. 8-Bit PWM Duty Cycle
Using Equation 20.2, the largest duty cycle is 100% (PCA0CPHn = 0), and the smallest duty cycle is
0.39% (PCA0CPHn = 0xFF). A 0% duty cycle may be generated by clearing the ECOMn bit to ‘0’.
PCA0CPHn
PCA0CPMn
P ECCMT P E
WC A A AOWC
MOPP TGMC
1 MP N n n n F
6 n n n
n
n
0
0 0 0 0
PCA0CPLn
0
Enable
8-bit
Comparator
match
S
R
PCA Timebase
PCA0L
SET
CLR
Q
CEXn
Crossbar
Q
Overflow
Figure 20.8. PCA 8-Bit PWM Mode Diagram
206
Rev. 0.3
Port I/O
C8051F52x-53x
20.2.6. 16-Bit Pulse Width Modulator Mode
A PCA module may also be operated in 16-Bit PWM mode. In this mode, the 16-bit capture/compare module defines the number of PCA clocks for the low time of the PWM signal. When the PCA counter matches
the module contents, the output on CEXn is asserted high; when the counter overflows, CEXn is asserted
low. To output a varying duty cycle, new value writes should be synchronized with PCA CCFn match interrupts. 16-Bit PWM Mode is enabled by setting the ECOMn, PWMn, and PWM16n bits in the PCA0CPMn
register. For a varying duty cycle, match interrupts should be enabled (ECCFn = 1 AND MATn = 1) to help
synchronize the capture/compare register writes. The duty cycle for 16-Bit PWM Mode is given by
Equation 20.3.
Important Note About Capture/Compare Registers: When writing a 16-bit value to the PCA0 Capture/Compare registers, the low byte should always be written first. Writing to PCA0CPLn clears the
ECOMn bit to ‘0’; writing to PCA0CPHn sets ECOMn to ‘1’.
( 65536 – PCA0CPn )
DutyCycle = ----------------------------------------------------65536
Equation 20.3. 16-Bit PWM Duty Cycle
Using Equation 20.3, the largest duty cycle is 100% (PCA0CPn = 0), and the smallest duty cycle is
0.0015% (PCA0CPn = 0xFFFF). A 0% duty cycle may be generated by clearing the ECOMn bit to ‘0’.
PCA0CPMn
P ECCMT P E
WC A A AOWC
MOPP TGMC
1 MP N n n n F
6 n n n
n
n
1
0 0 0 0
PCA0CPHn
PCA0CPLn
0
Enable
match
16-bit Comparator
S
R
PCA Timebase
PCA0H
PCA0L
SET
CLR
Q
CEXn
Crossbar
Port I/O
Q
Overflow
Figure 20.9. PCA 16-Bit PWM Mode
20.3. Watchdog Timer Mode
A programmable watchdog timer (WDT) function is available through the PCA Module 2. The WDT is used
to generate a reset if the time between writes to the WDT update register (PCA0CPH2) exceed a specified
limit. The WDT can be configured and enabled/disabled as needed by software.
With the WDTE bit set in the PCA0MD register, Module 2 operates as a watchdog timer (WDT). The
Module 2 high byte is compared to the PCA counter high byte; the Module 2 low byte holds the offset to be
used when WDT updates are performed. The Watchdog Timer is enabled on reset. Writes to some
PCA registers are restricted while the Watchdog Timer is enabled.
Rev. 0.3
207
C8051F52x-53x
20.3.1. Watchdog Timer Operation
While the WDT is enabled:
•
•
•
•
•
•
PCA counter is forced on.
Writes to PCA0L and PCA0H are not allowed.
PCA clock source bits (CPS2-CPS0) are frozen.
PCA Idle control bit (CIDL) is frozen.
Module 2 is forced into software timer mode.
Writes to the Module 2 mode register (PCA0CPM2) are disabled.
While the WDT is enabled, writes to the CR bit will not change the PCA counter state; the counter will run
until the WDT is disabled. The PCA counter run control (CR) will read zero if the WDT is enabled but user
software has not enabled the PCA counter. If a match occurs between PCA0CPH2 and PCA0H while the
WDT is enabled, a reset will be generated. To prevent a WDT reset, the WDT may be updated with a write
of any value to PCA0CPH2. Upon a PCA0CPH2 write, PCA0H plus the offset held in PCA0CPL2 is loaded
into PCA0CPH2 (See Figure 20.10).
PCA0MD
CWW
I D D
DT L
L E C
K
CCCE
PPPC
SSSF
2 1 0
PCA0CPH_
Enable
PCA0CPL_
Write to
PCA0CPH5
8-bit Adder
8-bit
Comparator
PCA0H
Match
Reset
PCA0L Overflow
Adder
Enable
Figure 20.10. PCA Module 2 with Watchdog Timer Enabled
208
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C8051F52x-53x
Note that the 8-bit offset held in PCA0CPH2 is compared to the upper byte of the 16-bit PCA counter. This
offset value is the number of PCA0L overflows before a reset. Up to 256 PCA clocks may pass before the
first PCA0L overflow occurs, depending on the value of the PCA0L when the update is performed. The
total offset is then given (in PCA clocks) by Equation 20.4, where PCA0L is the value of the PCA0L register
at the time of the update.
Offset = ( 256 × PCA0CPL2 ) + ( 256 – PCA0L )
Equation 20.4. Watchdog Timer Offset in PCA Clocks
The WDT reset is generated when PCA0L overflows while there is a match between PCA0CPH2 and
PCA0H. Software may force a WDT reset by writing a ‘1’ to the CCF2 flag (PCA0CN.2) while the WDT is
enabled.
20.3.2. Watchdog Timer Usage
To configure the WDT, perform the following tasks:
•
•
•
•
•
Disable the WDT by writing a ‘0’ to the WDTE bit.
Select the desired PCA clock source (with the CPS2-CPS0 bits).
Load PCA0CPL2 with the desired WDT update offset value.
Configure the PCA Idle mode (set CIDL if the WDT should be suspended while the CPU is in Idle
mode).
Enable the WDT by setting the WDTE bit to ‘1’.
The PCA clock source and Idle mode select cannot be changed while the WDT is enabled. The watchdog
timer is enabled by setting the WDTE or WDLCK bits in the PCA0MD register. When WDLCK is set, the
WDT cannot be disabled until the next system reset. If WDLCK is not set, the WDT is disabled by clearing
the WDTE bit.
The WDT is enabled following any reset. The PCA0 counter clock defaults to the system clock divided by
12, PCA0L defaults to 0x00, and PCA0CPL2 defaults to 0x00. Using Equation 20.4, this results in a WDT
timeout interval of 3072 system clock cycles. Table 20.3 lists some example timeout intervals for typical
system clocks.
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C8051F52x-53x
Table 20.3. Watchdog Timer Timeout Intervals1
System Clock (Hz)
24,500,000
24,500,000
24,500,000
18,432,000
18,432,000
18,432,000
11,059,200
11,059,200
11,059,200
3,062,500
3,062,500
3,062,500
191,4062
PCA0CPL2
255
128
32
255
128
32
255
128
32
255
128
32
255
Timeout Interval (ms)
32.1
16.2
4.1
42.7
21.5
5.5
71.1
35.8
9.2
257
129.5
33.1
4109
191,4062
128
2070
2
32
255
128
32
530
24576
12384
3168
191,406
32,000
32,000
32,000
Notes:
1. Assumes SYSCLK / 12 as the PCA clock source, and a PCA0L
value of 0x00 at the update time.
2. Internal oscillator reset frequency.
210
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C8051F52x-53x
20.4. Register Descriptions for PCA
Following are detailed descriptions of the special function registers related to the operation of the PCA.
SFR Definition 20.1. PCA0CN: PCA Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
CF
CR
—
—
—
CCF2
CCF1
CCF0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xD8
Bit7:
CF: PCA Counter/Timer Overflow Flag.
Set by hardware when the PCA Counter/Timer overflows from 0xFFFF to 0x0000. When the
Counter/Timer Overflow (CF) interrupt is enabled, setting this bit causes the CPU to vector
to the PCA interrupt service routine. This bit is not automatically cleared by hardware and
must be cleared by software.
Bit6:
CR: PCA Counter/Timer Run Control.
This bit enables/disables the PCA Counter/Timer.
0: PCA Counter/Timer disabled.
1: PCA Counter/Timer enabled.
Bits5–3: Reserved.
Bit2:
CCF2: PCA Module 2 Capture/Compare Flag.
This bit is set by hardware when a match or capture occurs. When the CCF2 interrupt is
enabled, setting this bit causes the CPU to vector to the PCA interrupt service routine. This
bit is not automatically cleared by hardware and must be cleared by software.
Bit1:
CCF1: PCA Module 1 Capture/Compare Flag.
This bit is set by hardware when a match or capture occurs. When the CCF1 interrupt is
enabled, setting this bit causes the CPU to vector to the PCA interrupt service routine. This
bit is not automatically cleared by hardware and must be cleared by software.
Bit0:
CCF0: PCA Module 0 Capture/Compare Flag.
This bit is set by hardware when a match or capture occurs. When the CCF0 interrupt is
enabled, setting this bit causes the CPU to vector to the PCA interrupt service routine. This
bit is not automatically cleared by hardware and must be cleared by software.
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C8051F52x-53x
SFR Definition 20.2. PCA0MD: PCA Mode
R/W
R/W
R/W
R
R/W
R/W
R/W
R/W
Reset Value
CIDL
WDTE
WDLCK
-
CPS2
CPS1
CPS0
ECF
01000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xD9
Bit7:
CIDL: PCA Counter/Timer Idle Control.
Specifies PCA behavior when CPU is in Idle Mode.
0: PCA continues to function normally while the system controller is in Idle Mode.
1: PCA operation is suspended while the system controller is in Idle Mode.
Bit6:
WDTE: Watchdog Timer Enable
If this bit is set, PCA Module 2 is used as the watchdog timer.
0: Watchdog Timer disabled.
1: PCA Module 2 enabled as Watchdog Timer.
Bit5:
WDLCK: Watchdog Timer Lock
This bit locks/unlocks the Watchdog Timer Enable. When WDLCK is set, the Watchdog
Timer may not be disabled until the next system reset.
0: Watchdog Timer Enable unlocked.
1: Watchdog Timer Enable locked.
Bit4:
UNUSED. Read = 0b, Write = don't care.
Bits3–1: CPS2–CPS0: PCA Counter/Timer Pulse Select.
These bits select the timebase source for the PCA counter.
CPS2
0
0
0
CPS1
0
0
1
CPS0
0
1
0
0
1
1
1
1
0
0
0
1
1
1
1
1
0
1
Timebase
System clock divided by 12
System clock divided by 4
Timer 0 overflow
High-to-low transitions on ECI (max rate = system clock
divided by 4)
System clock
External clock divided by 8*
RTC clock divided by 8*
Reserved
*Note: External clock divided by 8 and RTC0 clock divided by 8 are synchronized with the system
clock.
Bit0:
ECF: PCA Counter/Timer Overflow Interrupt Enable.
This bit sets the masking of the PCA Counter/Timer Overflow (CF) interrupt.
0: Disable the CF interrupt.
1: Enable a PCA Counter/Timer Overflow interrupt request when CF (PCA0CN.7) is set.
Note: When the WDTE bit is set to ‘1’, the PCA0MD register cannot be modified. To change the
contents of the PCA0MD register, the Watchdog Timer must first be disabled.
212
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C8051F52x-53x
SFR Definition 20.3. PCA0CPMn: PCA Capture/Compare Mode
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
PWM16n
ECOMn
CAPPn
CAPNn
MATn
TOGn
PWMn
ECCFn
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: PCA0CPM0: 0xDA, PCA0CPM1: 0xDB, PCA0CPM2: 0xDC
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
PWM16n: 16-bit Pulse Width Modulation Enable.
This bit selects 16-bit mode when Pulse Width Modulation mode is enabled (PWMn = 1).
0: 8-bit PWM selected.
1: 16-bit PWM selected.
ECOMn: Comparator Function Enable.
This bit enables/disables the comparator function for PCA module n.
0: Disabled.
1: Enabled.
CAPPn: Capture Positive Function Enable.
This bit enables/disables the positive edge capture for PCA module n.
0: Disabled.
1: Enabled.
CAPNn: Capture Negative Function Enable.
This bit enables/disables the negative edge capture for PCA module n.
0: Disabled.
1: Enabled.
MATn: Match Function Enable.
This bit enables/disables the match function for PCA module n. When enabled, matches of
the PCA counter with a module's capture/compare register cause the CCFn bit in PCA0MD
register to be set to logic 1.
0: Disabled.
1: Enabled.
TOGn: Toggle Function Enable.
This bit enables/disables the toggle function for PCA module n. When enabled, matches of
the PCA counter with a module's capture/compare register cause the logic level on the
CEXn pin to toggle. If the PWMn bit is also set to logic 1, the module operates in Frequency
Output Mode.
0: Disabled.
1: Enabled.
PWMn: Pulse Width Modulation Mode Enable.
This bit enables/disables the PWM function for PCA module n. When enabled, a pulse width
modulated signal is output on the CEXn pin. 8-bit PWM is used if PWM16n is cleared; 16-bit
mode is used if PWM16n is set to logic 1. If the TOGn bit is also set, the module operates in
Frequency Output Mode.
0: Disabled.
1: Enabled.
ECCFn: Capture/Compare Flag Interrupt Enable.
This bit sets the masking of the Capture/Compare Flag (CCFn) interrupt.
0: Disable CCFn interrupts.
1: Enable a Capture/Compare Flag interrupt request when CCFn is set.
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C8051F52x-53x
SFR Definition 20.4. PCA0L: PCA Counter/Timer Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: 0xF9
Bits7–0: PCA0L: PCA Counter/Timer Low Byte.
The PCA0L register holds the low byte (LSB) of the 16-bit PCA Counter/Timer.
SFR Definition 20.5. PCA0H: PCA Counter/Timer High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
SFR Address: 0xFA
Bits7–0: PCA0H: PCA Counter/Timer High Byte.
The PCA0H register holds the high byte (MSB) of the 16-bit PCA Counter/Timer.
SFR Definition 20.6. PCA0CPLn: PCA Capture Module Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: PCA0CPL0: 0xFB, PCA0CPL1: 0xE9, PCA0CPL2: 0xEB
Bits7–0: PCA0CPLn: PCA Capture Module Low Byte.
The PCA0CPLn register holds the low byte (LSB) of the 16-bit capture module n.
SFR Definition 20.7. PCA0CPHn: PCA Capture Module High Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reset Value
00000000
SFR Address: PCA0CPH0: 0xFC, PCA0CPH1: 0xE9, PCA0CPH2: 0xEC
Bits7–0: PCA0CPHn: PCA Capture Module High Byte.
The PCA0CPHn register holds the high byte (MSB) of the 16-bit capture module n.
214
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C8051F52x-53x
21. Revision Specific Behavior
This chapter contains behavioral differences between C8051F52x/F53x "REV_A" and “REV_B" or later
devices.
These differences do not affect the functionality or performance of most systems and are described below.
21.1. Revision Identification
The Lot ID Code on the top side of the device package can be used for decoding device revision information. On C8051F52x and C8051F53x devices the revision letter is the first letter of the Lot ID Code.
Figures 21.1, 21.2, and 21.3 show how to find the Lot ID Code on the top side of the device package.
C8051F530
BFAIXX
This character identifies the
Silicon Revision
e3
YYWW
Figure 21.1. Device Package - TSSOP 20
SIL
F530
BAEBK
0631+
This character identifies
the Silicon Revision
Figure 21.2. Device Package - QFN 20
Rev. 0.3
215
C8051F52x-53x
520
ANAB
628+
This character identifies
the Silicon Revision
Figure 21.3. Device Package - QFN 10
21.2. Reset Behavior
The reset behavior of C8051F52x and C8051F53x "REV A" devices is different than "REV B" and later
devices. The differences affect the state of the RST pin during a VDD Monitor reset.
On "REV A" devices, a VDD Monitor reset does not affect the state of the RST pin. On "REV B" and later
devices, a VDD Monitor reset will pull the RST pin low for the duration of the brownout condition.
21.3. UART Pins
The reset behavior of C8051F52x and C8051F53x "REV A" devices is different than "REV B" and later
devices. The location of the pins used by the serial UART interface is different between "REV A" and "REV
B" devices.
On "REV A" devices, the TX and RX pins used by the UART interface are mapped to the P0.3 (TX) and
P0.4 (RX) pins. On "REV B" and later devices, the TX and RX pins used by the UART interface are
mapped to the P0.4 (TX) and P0.5 (RX) pins.
21.4. LIN
The LIN peripheral behavior in "REV A" is different than the behavior of "REV B" and later devices. The
differences are:
21.4.1. Stop Bit Check
On "REV A" devices, the stop bits of the fields in the LIN frame are not checked and no error is generated
if the stop bits could not be sent or received correctly. On "REV B" and later devices, the stop bits are
checked, and an error will be generated if the stop bit was not sent or received correctly.
21.4.2. Synch Break and Synch Field Length Check
On "REV A" devices, the check of sync field length versus sync break length is incorrect. On "REV B" and
later devices, the sync break length must be larger than 10 bit times (of the measured bit time) to enable
the synchronization.
216
Rev. 0.3
C8051F52x-53x
22. C2 Interface
C8051F52x/F53x devices include an on-chip Silicon Laboratories 2-Wire (C2) debug interface to allow
Flash programming and in-system debugging with the production part installed in the end application. The
C2 interface uses a clock signal (C2CK) and a bi-directional C2 data signal (C2D) to transfer information
between the device and a host system. See the C2 Interface Specification for details on the C2 protocol.
22.1. C2 Interface Registers
The following describes the C2 registers necessary to perform Flash programming functions through the
C2 interface. All C2 registers are accessed through the C2 interface as described in the C2 Interface Specification.
C2 Register Definition 22.1. C2ADD: C2 Address
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits7–0: The C2ADD register is accessed via the C2 interface to select the target Data register for
C2 Data Read and Data Write commands.
Address
0x00
0x01
0x02
0xB4
Description
Selects the Device ID register for Data Read instructions (DEVICEID)
Selects the Revision ID register for Data Read instructions (REVID)
Selects the C2 Flash Programming Control register for Data Read/Write instructions
(FPCTL)
Selects the C2 Flash Programming Data register for Data Read/Write instructions
(FPDAT)
C2 Register Definition 22.2. DEVICEID: C2 Device ID
Reset Value
00010001
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
This read-only register returns the 8-bit device ID: 0x11 (C8051F52x/C8051F53x).
Rev. 0.3
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C8051F52x-53x
C2 Register Definition 22.3. REVID: C2 Revision ID
Reset Value
Varies
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
This read-only register returns the 8-bit revision ID.
For example, 0x00 = Revision A.
C2 Register Definition 22.4. FPCTL: C2 Flash Programming Control
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits7–0 FPCTL: Flash Programming Control Register.
This register is used to enable Flash programming via the C2 interface. To enable C2 Flash
programming, the following codes must be written in order: 0x02, 0x01. Note that once C2
Flash programming is enabled, a system reset must be issued to resume normal operation.
C2 Register Definition 22.5. FPDAT: C2 Flash Programming Data
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bits7–0: FPDAT: C2 Flash Programming Data Register.
This register is used to pass Flash commands, addresses, and data during C2 Flash
accesses. Valid commands are listed below.
Code
0x06
0x07
0x08
0x03
218
Command
Flash Block Read
Flash Block Write
Flash Page Erase
Device Erase
Rev. 0.3
C8051F52x-53x
22.2. C2 Pin Sharing
The C2 protocol allows the C2 pins to be shared with user functions so that in-system debugging and
Flash programming functions may be performed. This is possible because C2 communication is typically
performed when the device is in the halt state, where all on-chip peripherals and user software are stalled.
In this halted state, the C2 interface can safely ‘borrow’ the C2CK (/RST) and C2D (P2.7) pins. In most
applications, external resistors are required to isolate C2 interface traffic from the user application. A typical isolation configuration is shown in Figure 22.1.
C8051Fxxx
/Reset (a)
C2CK
Input (b)
C2D
Output (c)
C2 Interface Master
Figure 22.1. Typical C2 Pin Sharing
The configuration in Figure 22.1 assumes the following:
1. The user input (b) cannot change state while the target device is halted.
2. The /RST pin on the target device is used as an input only.
Additional resistors may be necessary depending on the specific application.
Rev. 0.3
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C8051F52x-53x
CONTACT INFORMATION
Silicon Laboratories Inc.
400 West Cesar Chavez
Austin, TX 78701
Tel: 1+(512) 416-8500
Fax: 1+(512) 416-9669
Toll Free: 1+(877) 444-3032
Email: [email protected]
Internet: www.silabs.com
The information in this document is believed to be accurate in all respects at the time of publication but is subject to change without
notice. Silicon Laboratories assumes no responsibility for errors and omissions, and disclaims responsibility for any consequences
resulting from the use of information included herein. Additionally, Silicon Laboratories assumes no responsibility for the functioning of undescribed features or parameters. Silicon Laboratories reserves the right to make changes without further notice. Silicon
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