C8051F41x 2.0 V 32 kB and 16 kB Flash SmaRTClock 12-bit ADC

C8051F410/1/2/3
2.0 V, 32/16 kB Flash, smaRTClock, 12-bit ADC
Analog Peripherals
- 12-Bit ADC
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±1 LSB INL; no missing codes
Programmable throughput up to 200 ksps
Up to 24 external inputs
Data dependent windowed interrupt generator
Built-in temperature sensor (±3 °C)
Two 12-Bit Current Mode DACs
Two Comparators
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Programmable hysteresis and response time
Configurable as wake-up or reset source
- POR/Brownout Detector
- Voltage Reference—1.5, 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 2.0 to 5.25 V
- Built-in LDO regulator: 2.1 or 2.5 V
High Speed 8051 μC Core
- Pipelined instruction architecture; executes 70% of
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instructions in 1 or 2 system clocks
Up to 50 MIPS throughput with
50 MHz system clock
Expanded interrupt handler
Rev. 1.1 11/08
Memory
- 2304 bytes internal data RAM (256 + 2048)
- 32/16 kB Flash; In-system programmable in
512 byte sectors
- 64 bytes battery-backed RAM (smaRTClock)
Digital Peripherals
- 24 port I/O; push-pull or open-drain, up to 5.25 V
-
tolerance
Hardware SMBus™ (I2C™ Compatible), SPI™, and
UART serial ports available concurrently
Four general purpose 16-bit counter/timers
Programmable 16-bit counter/timer array with six
capture/compare modules, WDT
Hardware smaRTClock operates down to 1 V with
64 bytes battery-backed RAM and backup voltage
regulator
Clock Sources
- Internal oscillators: 24.5 MHz 2% accuracy supports
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UART operation; clock multiplier up to 50 MHz
External oscillator: Crystal, RC, C, or Clock
(1 or 2 pin modes)
smaRTClock oscillator: 32 kHz Crystal or
self-resonant oscillator
Can switch between clock sources on-the-fly
32-Pin LQFP or 28-Pin 5 x 5 QFN
Temperature Range: –40 to +85 °C
Copyright © 2008 by Silicon Laboratories
C8051F41x
C8051F410/1/2/3
NOTES:
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Rev. 1.1
C8051F410/1/2/3
Table of Contents
1. System Overview.................................................................................................... 19
1.1. CIP-51™ Microcontroller................................................................................... 25
1.1.1. Fully 8051 Compatible Instruction Set...................................................... 25
1.1.2. Improved Throughput ............................................................................... 25
1.1.3. Additional Features .................................................................................. 25
1.2. On-Chip Debug Circuitry................................................................................... 26
1.3. On-Chip Memory............................................................................................... 27
1.4. Operating Modes .............................................................................................. 28
1.5. 12-Bit Analog to Digital Converter..................................................................... 29
1.6. Two 12-bit Current-Mode DACs........................................................................ 29
1.7. Programmable Comparators............................................................................. 30
1.8. Cyclic Redundancy Check Unit......................................................................... 31
1.9. Voltage Regulator ............................................................................................. 31
1.10.Serial Ports ....................................................................................................... 31
1.11.smaRTClock (Real Time Clock) ....................................................................... 32
1.12.Port Input/Output .............................................................................................. 33
1.13.Programmable Counter Array........................................................................... 34
2. Absolute Maximum Ratings .................................................................................. 35
3. Global DC Electrical Characteristics .................................................................... 36
4. Pinout and Package Definitions............................................................................ 41
5. 12-Bit ADC (ADC0).................................................................................................. 51
5.1. Analog Multiplexer ............................................................................................ 51
5.2. Temperature Sensor ......................................................................................... 52
5.3. ADC0 Operation................................................................................................ 52
5.3.1. Starting a Conversion............................................................................... 53
5.3.2. Tracking Modes........................................................................................ 53
5.3.3. Timing....................................................................................................... 54
5.3.4. Burst Mode ............................................................................................... 56
5.3.5. Output Conversion Code.......................................................................... 57
5.3.6. Settling Time Requirements ..................................................................... 58
5.4. Programmable Window Detector ...................................................................... 63
5.4.1. Window Detector In Single-Ended Mode ................................................. 66
6. 12-Bit Current Mode DACs (IDA0 and IDA1) ........................................................ 69
6.1. IDAC Output Scheduling................................................................................... 69
6.1.1. Update Output On-Demand ..................................................................... 69
6.1.2. Update Output Based on Timer Overflow ................................................ 70
6.1.3. Update Output Based on CNVSTR Edge................................................. 70
6.2. IDAC Output Mapping....................................................................................... 70
6.3. IDAC External Pin Connections ........................................................................ 73
7. Voltage Reference .................................................................................................. 77
8. Voltage Regulator (REG0)...................................................................................... 81
9. Comparators ......................................................................................................... 83
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10. CIP-51 Microcontroller ........................................................................................... 93
10.1.Instruction Set................................................................................................... 94
10.1.1.Instruction and CPU Timing ..................................................................... 94
10.1.2.MOVX Instruction and Program Memory ................................................. 95
10.2.Register Descriptions ....................................................................................... 98
10.3.Power Management Modes............................................................................ 101
10.3.1.Idle Mode ............................................................................................... 102
10.3.2.Stop Mode.............................................................................................. 102
10.3.3.Suspend Mode ....................................................................................... 102
11. Memory Organization and SFRs ......................................................................... 103
11.1.Program Memory............................................................................................ 103
11.2.Data Memory .................................................................................................. 104
11.3.General Purpose Registers ............................................................................ 104
11.4.Bit Addressable Locations .............................................................................. 104
11.5.Stack............................................................................................................... 104
11.6.Special Function Registers............................................................................. 105
12. Interrupt Handler .................................................................................................. 110
12.1.MCU Interrupt Sources and Vectors............................................................... 110
12.2.Interrupt Priorities ........................................................................................... 110
12.3.Interrupt Latency............................................................................................. 110
12.4.Interrupt Register Descriptions ....................................................................... 112
12.5.External Interrupts .......................................................................................... 117
13. Prefetch Engine .................................................................................................... 119
14. Cyclic Redundancy Check Unit (CRC0) ............................................................. 121
14.1.16-bit CRC Algorithm...................................................................................... 121
14.2.32-bit CRC Algorithm...................................................................................... 123
14.3.Preparing for a CRC Calculation .................................................................... 124
14.4.Performing a CRC Calculation ....................................................................... 124
14.5.Accessing the CRC0 Result ........................................................................... 124
14.6.CRC0 Bit Reverse Feature............................................................................. 124
15. Reset Sources....................................................................................................... 127
15.1.Power-On Reset ............................................................................................. 128
15.2.Power-Fail Reset / VDD Monitor .................................................................... 129
15.3.External Reset ................................................................................................ 130
15.4.Missing Clock Detector Reset ........................................................................ 130
15.5.Comparator0 Reset ........................................................................................ 130
15.6.PCA Watchdog Timer Reset .......................................................................... 131
15.7.Flash Error Reset ........................................................................................... 131
15.8.smaRTClock (Real Time Clock) Reset........................................................... 132
15.9.Software Reset ............................................................................................... 132
16. Flash Memory ....................................................................................................... 135
16.1.Programming The Flash Memory ................................................................... 135
16.1.1.Flash Lock and Key Functions ............................................................... 135
16.1.2.Flash Erase Procedure .......................................................................... 135
16.1.3.Flash Write Procedure ........................................................................... 136
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16.2.Non-volatile Data Storage .............................................................................. 137
16.3.Security Options ............................................................................................. 137
16.4.Flash Write and Erase Guidelines .................................................................. 139
16.4.1.VDD Maintenance and the VDD Monitor ............................................... 139
16.4.2.16.4.2 PSWE Maintenance .................................................................... 140
16.4.3.System Clock ......................................................................................... 140
16.5.Flash Read Timing ......................................................................................... 142
17. External RAM ........................................................................................................ 145
18. Port Input/Output.................................................................................................. 147
18.1.Priority Crossbar Decoder .............................................................................. 149
18.2.Port I/O Initialization ....................................................................................... 151
18.3.General Purpose Port I/O ............................................................................... 154
19. Oscillators ............................................................................................................. 165
19.1.Programmable Internal Oscillator ................................................................... 165
19.1.1.Internal Oscillator Suspend Mode .......................................................... 166
19.2.External Oscillator Drive Circuit...................................................................... 168
19.2.1.Clocking Timers Directly Through the External Oscillator...................... 168
19.2.2.External Crystal Example....................................................................... 168
19.2.3.External RC Example............................................................................. 170
19.2.4.External Capacitor Example................................................................... 170
19.3.Clock Multiplier ............................................................................................... 172
19.4.System Clock Selection.................................................................................. 174
20. smaRTClock (Real Time Clock)........................................................................... 177
20.1.smaRTClock Interface .................................................................................... 178
20.1.1.smaRTClock Lock and Key Functions ................................................... 178
20.1.2.Using RTC0ADR and RTC0DAT to Access
smaRTClock Internal Registers ............................................................. 178
20.1.3.smaRTClock Interface Autoread Feature............................................... 178
20.1.4.RTC0ADR Autoincrement Feature......................................................... 179
20.2.smaRTClock Clocking Sources ...................................................................... 182
20.2.1.Using the smaRTClock Oscillator in Crystal Mode ................................ 182
20.2.2.Using the smaRTClock Oscillator in Self-Oscillate Mode ...................... 182
20.2.3.Automatic Gain Control (Crystal Mode Only) ......................................... 183
20.2.4.smaRTClock Bias Doubling ................................................................... 183
20.2.5.smaRTClock Missing Clock Detector..................................................... 183
20.3.smaRTClock Timer and Alarm Function......................................................... 185
20.3.1.Setting and Reading the smaRTClock Timer Value............................... 185
20.3.2.Setting a smaRTClock Alarm ................................................................. 186
20.4.Backup Regulator and RAM ........................................................................... 187
21. SMBus ................................................................................................................... 191
21.1.Supporting Documents ................................................................................... 192
21.2.SMBus Configuration...................................................................................... 192
21.3.SMBus Operation ........................................................................................... 192
21.3.1.Arbitration............................................................................................... 193
21.3.2.Clock Low Extension.............................................................................. 193
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21.3.3.SCL Low Timeout................................................................................... 194
21.3.4.SCL High (SMBus Free) Timeout .......................................................... 194
21.4.Using the SMBus............................................................................................ 194
21.4.1.SMBus Configuration Register............................................................... 195
21.4.2.SMB0CN Control Register ..................................................................... 198
21.4.3.Data Register ......................................................................................... 201
21.5.SMBus Transfer Modes.................................................................................. 201
21.5.1.Master Transmitter Mode ....................................................................... 201
21.5.2.Master Receiver Mode ........................................................................... 202
21.5.3.Slave Receiver Mode ............................................................................. 203
21.5.4.Slave Transmitter Mode ......................................................................... 204
21.6.SMBus Status Decoding................................................................................. 204
22. UART0.................................................................................................................... 207
22.1.Enhanced Baud Rate Generation................................................................... 208
22.2.Operational Modes ......................................................................................... 209
22.2.1.8-Bit UART ............................................................................................. 209
22.2.2.9-Bit UART ............................................................................................. 210
22.3.Multiprocessor Communications .................................................................... 210
23. Enhanced Serial Peripheral Interface (SPI0)...................................................... 217
23.1.Signal Descriptions......................................................................................... 218
23.1.1.Master Out, Slave In (MOSI).................................................................. 218
23.1.2.Master In, Slave Out (MISO).................................................................. 218
23.1.3.Serial Clock (SCK) ................................................................................. 218
23.1.4.Slave Select (NSS) ................................................................................ 218
23.2.SPI0 Master Mode Operation ......................................................................... 219
23.3.SPI0 Slave Mode Operation ........................................................................... 220
23.4.SPI0 Interrupt Sources ................................................................................... 221
23.5.Serial Clock Timing......................................................................................... 221
23.6.SPI Special Function Registers ...................................................................... 222
24. Timers.................................................................................................................... 231
24.1.Timer 0 and Timer 1 ....................................................................................... 231
24.1.1.Mode 0: 13-bit Counter/Timer ................................................................ 231
24.1.2.Mode 1: 16-bit Counter/Timer ................................................................ 233
24.1.3.Mode 2: 8-bit Counter/Timer with Auto-Reload...................................... 233
24.1.4.Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)................................. 234
24.2.Timer 2 ........................................................................................................... 239
24.2.1.16-bit Timer with Auto-Reload................................................................ 239
24.2.2.8-bit Timers with Auto-Reload................................................................ 240
24.2.3.External/smaRTClock Capture Mode..................................................... 241
24.3.Timer 3 ........................................................................................................... 244
24.3.1.16-bit Timer with Auto-Reload................................................................ 244
24.3.2.8-bit Timers with Auto-Reload................................................................ 245
24.3.3.External/smaRTClock Capture Mode..................................................... 246
25. Programmable Counter Array (PCA0) ................................................................ 249
25.1.PCA Counter/Timer ........................................................................................ 250
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25.2.Capture/Compare Modules ............................................................................ 251
25.2.1.Edge-triggered Capture Mode................................................................ 252
25.2.2.Software Timer (Compare) Mode........................................................... 253
25.2.3.High Speed Output Mode....................................................................... 254
25.2.4.Frequency Output Mode ........................................................................ 255
25.2.5.8-Bit Pulse Width Modulator Mode......................................................... 256
25.2.6.16-Bit Pulse Width Modulator Mode....................................................... 257
25.3.Watchdog Timer Mode ................................................................................... 257
25.3.1.Watchdog Timer Operation .................................................................... 258
25.3.2.Watchdog Timer Usage ......................................................................... 259
25.4.Register Descriptions for PCA........................................................................ 261
26. C2 Interface ........................................................................................................... 265
26.1.C2 Interface Registers.................................................................................... 265
26.2.C2 Pin Sharing ............................................................................................... 267
Rev. 1.1
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NOTES:
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C8051F410/1/2/3
List of Figures
1. System Overview
Figure 1.1. C8051F410 Block Diagram .................................................................... 21
Figure 1.2. C8051F411 Block Diagram .................................................................... 22
Figure 1.3. C8051F412 Block Diagram .................................................................... 23
Figure 1.4. C8051F413 Block Diagram .................................................................... 24
Figure 1.5. Development/In-System Debug Diagram............................................... 26
Figure 1.6. Memory Map .......................................................................................... 27
Figure 1.7. 12-Bit ADC Block Diagram..................................................................... 29
Figure 1.8. IDAC Block Diagram .............................................................................. 30
Figure 1.9. Comparators Block Diagram .................................................................. 31
Figure 1.10. smaRTClock Block Diagram ................................................................ 32
Figure 1.11. Port I/O Functional Block Diagram ....................................................... 33
Figure 1.12. PCA Block Diagram.............................................................................. 34
2. Absolute Maximum Ratings
3. Global DC Electrical Characteristics
4. Pinout and Package Definitions
Figure 4.1. LQFP-32 Pinout Diagram (Top View) .................................................... 44
Figure 4.2. QFN-28 Pinout Diagram (Top View) ...................................................... 45
Figure 4.3. LQFP-32 Package Diagram ................................................................... 46
Figure 4.4. LQFP-32 Recommended PCB Land Pattern ......................................... 47
Figure 4.5. QFN-28 Package Drawing ..................................................................... 48
Figure 4.6. QFN-28 Recommended PCB Land Pattern ........................................... 49
5. 12-Bit ADC (ADC0)
Figure 5.1. ADC0 Functional Block Diagram............................................................ 51
Figure 5.2. Typical Temperature Sensor Transfer Function..................................... 52
Figure 5.3. ADC0 Tracking Modes ........................................................................... 54
Figure 5.4. 12-Bit ADC Tracking Mode Example ..................................................... 55
Figure 5.5. 12-Bit ADC Burst Mode Example with Repeat Count Set to 4............... 56
Figure 5.6. ADC0 Equivalent Input Circuits.............................................................. 58
Figure 5.7. ADC Window Compare Example: Right-Justified Single-Ended Data ... 66
Figure 5.8. ADC Window Compare Example: Left-Justified Single-Ended Data ..... 66
6. 12-Bit Current Mode DACs (IDA0 and IDA1)
Figure 6.1. IDAC Functional Block Diagram............................................................. 69
Figure 6.2. IDAC Data Word Mapping...................................................................... 70
Figure 6.3. IDAC Pin Connections ........................................................................... 74
7. Voltage Reference
Figure 7.1. Voltage Reference Functional Block Diagram ....................................... 77
8. Voltage Regulator (REG0)
Figure 8.1. External Capacitors for Voltage Regulator Input/Output ........................ 81
Figure 8.2. External Capacitors for Voltage Regulator Input/Output ........................ 81
9. Comparators
Figure 9.1. Comparator0 Functional Block Diagram ................................................ 83
Figure 9.2. Comparator1 Functional Block Diagram ................................................ 84
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Figure 9.3. Comparator Hysteresis Plot ................................................................... 85
10. CIP-51 Microcontroller
Figure 10.1. CIP-51 Block Diagram.......................................................................... 93
11. Memory Organization and SFRs
Figure 11.1. Memory Map ...................................................................................... 103
12. Interrupt Handler
13. Prefetch Engine
14. Cyclic Redundancy Check Unit (CRC0)
Figure 14.1. CRC0 Block Diagram ......................................................................... 121
Figure 14.2. Bit Reverse Register .......................................................................... 124
15. Reset Sources
Figure 15.1. Reset Sources.................................................................................... 127
Figure 15.2. Power-On and VDD Monitor Reset Timing ........................................ 128
16. Flash Memory
Figure 16.1. Flash Program Memory Map.............................................................. 137
17. External RAM
18. Port Input/Output
Figure 18.1. Port I/O Functional Block Diagram ..................................................... 147
Figure 18.2. Port I/O Cell Block Diagram ............................................................... 148
Figure 18.3. Crossbar Priority Decoder with No Pins Skipped ............................... 149
Figure 18.4. Crossbar Priority Decoder with Crystal Pins Skipped ........................ 150
Figure 18.5. Port 0 Input Overdrive Current Range................................................ 152
19. Oscillators
Figure 19.1. Oscillator Diagram.............................................................................. 165
Figure 19.2. 32.768 kHz External Crystal Example................................................ 169
Figure 19.3. Example Clock Multiplier Output ........................................................ 172
20. smaRTClock (Real Time Clock)
Figure 20.1. smaRTClock Block Diagram .............................................................. 177
21. SMBus
Figure 21.1. SMBus Block Diagram ....................................................................... 191
Figure 21.2. Typical SMBus Configuration ............................................................. 192
Figure 21.3. SMBus Transaction ............................................................................ 193
Figure 21.4. Typical SMBus SCL Generation......................................................... 196
Figure 21.5. Typical Master Transmitter Sequence................................................ 202
Figure 21.6. Typical Master Receiver Sequence.................................................... 202
Figure 21.7. Typical Slave Receiver Sequence...................................................... 203
Figure 21.8. Typical Slave Transmitter Sequence.................................................. 204
22. UART0
Figure 22.1. UART0 Block Diagram ....................................................................... 207
Figure 22.2. UART0 Baud Rate Logic .................................................................... 208
Figure 22.3. UART Interconnect Diagram .............................................................. 209
Figure 22.4. 8-Bit UART Timing Diagram............................................................... 209
Figure 22.5. 9-Bit UART Timing Diagram............................................................... 210
Figure 22.6. UART Multi-Processor Mode Interconnect Diagram .......................... 211
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23. Enhanced Serial Peripheral Interface (SPI0)
Figure 23.1. SPI Block Diagram ............................................................................. 217
Figure 23.2. Multiple-Master Mode Connection Diagram ....................................... 220
Figure 23.3. 3-Wire Single Master and Slave Mode Connection Diagram ............. 220
Figure 23.4. 4-Wire Single Master and Slave Mode Connection Diagram ............. 220
Figure 23.5. Data/Clock Timing Relationship ......................................................... 222
Figure 23.6. SPI Master Timing (CKPHA = 0)........................................................ 227
Figure 23.7. SPI Master Timing (CKPHA = 1)........................................................ 227
Figure 23.8. SPI Slave Timing (CKPHA = 0).......................................................... 228
Figure 23.9. SPI Slave Timing (CKPHA = 1).......................................................... 228
24. Timers
Figure 24.1. T0 Mode 0 Block Diagram.................................................................. 232
Figure 24.2. T0 Mode 2 Block Diagram.................................................................. 233
Figure 24.3. T0 Mode 3 Block Diagram.................................................................. 234
Figure 24.4. Timer 2 16-Bit Mode Block Diagram .................................................. 239
Figure 24.5. Timer 2 8-Bit Mode Block Diagram .................................................... 240
Figure 24.6. Timer 2 Capture Mode Block Diagram ............................................... 241
Figure 24.7. Timer 3 16-Bit Mode Block Diagram .................................................. 244
Figure 24.8. Timer 3 8-Bit Mode Block Diagram .................................................... 245
Figure 24.9. Timer 3 Capture Mode Block Diagram ............................................... 246
25. Programmable Counter Array (PCA0)
Figure 25.1. PCA Block Diagram............................................................................ 249
Figure 25.2. PCA Counter/Timer Block Diagram.................................................... 250
Figure 25.3. PCA Interrupt Block Diagram ............................................................. 251
Figure 25.4. PCA Capture Mode Diagram.............................................................. 252
Figure 25.5. PCA Software Timer Mode Diagram .................................................. 253
Figure 25.6. PCA High-Speed Output Mode Diagram............................................ 254
Figure 25.7. PCA Frequency Output Mode ............................................................ 255
Figure 25.8. PCA 8-Bit PWM Mode Diagram ......................................................... 256
Figure 25.9. PCA 16-Bit PWM Mode...................................................................... 257
Figure 25.10. PCA Module 5 with Watchdog Timer Enabled ................................. 258
26. C2 Interface
Figure 26.1. Typical C2 Pin Sharing....................................................................... 267
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List of Tables
1. System Overview
Table 1.1. Product Selection Guide ......................................................................... 20
Table 1.2. Operating Modes Summary .................................................................... 28
2. Absolute Maximum Ratings
Table 2.1.Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3. Global DC Electrical Characteristics
Table 3.1.Global DC Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 3.2. Index to Electrical Characteristics Tables ............................................... 39
4. Pinout and Package Definitions
Table 4.1. Pin Definitions for the C8051F41x .......................................................... 41
Table 4.2. LQFP-32 Package Dimensions .............................................................. 46
Table 4.3. LQFP-32 PCB Land Pattern Dimensions ............................................... 47
Table 4.4. QFN-28 Package Dimensions ................................................................ 48
Table 4.5. QFN-28 PCB Land Pattern Dimensions ................................................. 49
5. 12-Bit ADC (ADC0)
Table 5.1. ADC0 Examples of Right- and Left-Justified Samples ........................... 57
Table 5.2. ADC0 Repeat Count Examples at Various Input Voltages ..................... 57
Table 5.3.ADC0 Electrical Characteristics (VDD = 2.5 V, VREF = 2.2 V) . . . . . . . . 67
Table 5.4.ADC0 Electrical Characteristics (VDD = 2.1 V, VREF = 1.5 V) . . . . . . . . 68
6. 12-Bit Current Mode DACs (IDA0 and IDA1)
Table 6.1.IDAC Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
7. Voltage Reference
Table 7.1.Voltage Reference Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . 79
8. Voltage Regulator (REG0)
Table 8.1.Voltage Regulator Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . 82
9. Comparators
Table 9.1.Comparator Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 92
10. CIP-51 Microcontroller
Table 10.1. CIP-51 Instruction Set Summary .......................................................... 95
11. Memory Organization and SFRs
Table 11.1. Special Function Register (SFR) Memory Map .................................. 105
Table 11.2. Special Function Registers ................................................................. 106
12. Interrupt Handler
Table 12.1. Interrupt Summary .............................................................................. 111
13. Prefetch Engine
14. Cyclic Redundancy Check Unit (CRC0)
Table 14.1. Example 16-bit CRC Outputs ............................................................. 122
Table 14.2. Example 32-bit CRC Outputs ............................................................. 124
15. Reset Sources
Table 15.1.Reset Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
16. Flash Memory
Table 16.1. Flash Security Summary .................................................................... 138
Table 16.2.Flash Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
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17. External RAM
18. Port Input/Output
Table 18.1.Port I/O DC Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . 163
19. Oscillators
Table 19.1.Oscillator Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 175
20. smaRTClock (Real Time Clock)
Table 20.1. smaRTClock Internal Registers .......................................................... 179
21. SMBus
Table 21.1. SMBus Clock Source Selection .......................................................... 195
Table 21.2. Minimum SDA Setup and Hold Times ................................................ 196
Table 21.3. Sources for Hardware Changes to SMB0CN ..................................... 200
Table 21.4. SMBus Status Decoding ..................................................................... 205
22. UART0
Table 22.1. Timer Settings for Standard Baud Rates
Using the Internal Oscillator ............................................................... 214
Table 22.2. Timer Settings for Standard Baud Rates
Using an External 25.0 MHz Oscillator ............................................... 214
Table 22.3. Timer Settings for Standard Baud Rates
Using an External 22.1184 MHz Oscillator ......................................... 215
Table 22.4. Timer Settings for Standard Baud Rates
Using an External 18.432 MHz Oscillator ........................................... 215
Table 22.5. Timer Settings for Standard Baud Rates
Using an External 11.0592 MHz Oscillator ......................................... 216
Table 22.6. Timer Settings for Standard Baud Rates
Using an External 3.6864 MHz Oscillator ........................................... 216
23. Enhanced Serial Peripheral Interface (SPI0)
Table 23.1.SPI Slave Timing Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
24. Timers
25. Programmable Counter Array (PCA0)
Table 25.1. PCA Timebase Input Options ............................................................. 250
Table 25.2. PCA0CPM Register Settings for PCA Capture/Compare Modules .... 251
Table 25.3. Watchdog Timer Timeout Intervals ..................................................... 260
26. C2 Interface
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List of Registers
SFR Definition 5.1. ADC0MX: ADC0 Channel Select . . . . . . . . . . . . . . . . . . . . . . . . . . 59
SFR Definition 5.2. ADC0CF: ADC0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
SFR Definition 5.3. ADC0H: ADC0 Data Word MSB . . . . . . . . . . . . . . . . . . . . . . . . . . 61
SFR Definition 5.4. ADC0L: ADC0 Data Word LSB . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
SFR Definition 5.5. ADC0CN: ADC0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
SFR Definition 5.6. ADC0TK: ADC0 Tracking Mode Select . . . . . . . . . . . . . . . . . . . . 63
SFR Definition 5.7. ADC0GTH: ADC0 Greater-Than Data High Byte . . . . . . . . . . . . . 64
SFR Definition 5.8. ADC0GTL: ADC0 Greater-Than Data Low Byte . . . . . . . . . . . . . . 64
SFR Definition 5.9. ADC0LTH: ADC0 Less-Than Data High Byte . . . . . . . . . . . . . . . . 65
SFR Definition 5.10. ADC0LTL: ADC0 Less-Than Data Low Byte . . . . . . . . . . . . . . . . 65
SFR Definition 6.1. IDA0CN: IDA0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
SFR Definition 6.2. IDA0H: IDA0 Data High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
SFR Definition 6.3. IDA0L: IDA0 Data Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
SFR Definition 6.4. IDA1CN: IDA1 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
SFR Definition 6.5. IDA1H: IDA0 Data High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
SFR Definition 6.6. IDA1L: IDA1 Data Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
SFR Definition 7.1. REF0CN: Reference Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
SFR Definition 8.1. REG0CN: Regulator Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
SFR Definition 9.1. CPT0CN: Comparator0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
SFR Definition 9.2. CPT0MX: Comparator0 MUX Selection . . . . . . . . . . . . . . . . . . . . 87
SFR Definition 9.3. CPT0MD: Comparator0 Mode Selection . . . . . . . . . . . . . . . . . . . . 88
SFR Definition 9.4. CPT1MX: Comparator1 MUX Selection . . . . . . . . . . . . . . . . . . . . 89
SFR Definition 9.5. CPT1MD: Comparator1 Mode Selection . . . . . . . . . . . . . . . . . . . . 90
SFR Definition 9.6. CPT1CN: Comparator1 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
SFR Definition 10.1. SP: Stack Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
SFR Definition 10.2. DPL: Data Pointer Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
SFR Definition 10.3. DPH: Data Pointer High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
SFR Definition 10.4. PSW: Program Status Word . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
SFR Definition 10.5. ACC: Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
SFR Definition 10.6. B: B Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
SFR Definition 10.7. PCON: Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
SFR Definition 12.1. IE: Interrupt Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
SFR Definition 12.2. IP: Interrupt Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
SFR Definition 12.3. EIE1: Extended Interrupt Enable 1 . . . . . . . . . . . . . . . . . . . . . . 114
SFR Definition 12.4. EIP1: Extended Interrupt Priority 1 . . . . . . . . . . . . . . . . . . . . . . 115
SFR Definition 12.5. EIE2: Extended Interrupt Enable 2 . . . . . . . . . . . . . . . . . . . . . . 116
SFR Definition 12.6. EIP2: Extended Interrupt Priority 2 . . . . . . . . . . . . . . . . . . . . . . 116
SFR Definition 12.7. IT01CF: INT0/INT1 Configuration . . . . . . . . . . . . . . . . . . . . . . . 118
SFR Definition 13.1. PFE0CN: Prefetch Engine Control . . . . . . . . . . . . . . . . . . . . . . 119
SFR Definition 14.1. CRC0CN: CRC0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
SFR Definition 14.2. CRC0IN: CRC0 Data Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
SFR Definition 14.3. CRC0DAT: CRC0 Data Output . . . . . . . . . . . . . . . . . . . . . . . . . 126
SFR Definition 14.4. CRC0FLIP: CRC0 Bit Flip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Rev. 1.1
15
C8051F410/1/2/3
SFR Definition 15.1. VDM0CN: VDD Monitor Control . . . . . . . . . . . . . . . . . . . . . . . . 130
SFR Definition 15.2. RSTSRC: Reset Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
SFR Definition 16.1. PSCTL: Program Store R/W Control . . . . . . . . . . . . . . . . . . . . . 141
SFR Definition 16.2. FLKEY: Flash Lock and Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
SFR Definition 16.3. FLSCL: Flash Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
SFR Definition 16.4. ONESHOT: Flash Oneshot Period . . . . . . . . . . . . . . . . . . . . . . 143
SFR Definition 17.1. EMI0CN: External Memory Interface Control . . . . . . . . . . . . . . 145
SFR Definition 18.1. XBR0: Port I/O Crossbar Register 0 . . . . . . . . . . . . . . . . . . . . . 153
SFR Definition 18.2. XBR1: Port I/O Crossbar Register 1 . . . . . . . . . . . . . . . . . . . . . 154
SFR Definition 18.3. P0: Port0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
SFR Definition 18.4. P0MDIN: Port0 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
SFR Definition 18.5. P0MDOUT: Port0 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . . 156
SFR Definition 18.6. P0SKIP: Port0 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
SFR Definition 18.7. P0MAT: Port0 Match . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
SFR Definition 18.8. P0MASK: Port0 Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
SFR Definition 18.9. P0ODEN: Port0 Overdrive Mode . . . . . . . . . . . . . . . . . . . . . . . . 157
SFR Definition 18.10. P1: Port1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
SFR Definition 18.11. P1MDIN: Port1 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
SFR Definition 18.12. P1MDOUT: Port1 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . 159
SFR Definition 18.13. P1SKIP: Port1 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
SFR Definition 18.14. P1MAT: Port1 Match . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
SFR Definition 18.15. P1MASK: Port1 Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
SFR Definition 18.16. P2: Port2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
SFR Definition 18.17. P2MDIN: Port2 Input Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
SFR Definition 18.18. P2MDOUT: Port2 Output Mode . . . . . . . . . . . . . . . . . . . . . . . . 162
SFR Definition 18.19. P2SKIP: Port2 Skip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
SFR Definition 19.1. OSCICN: Internal Oscillator Control . . . . . . . . . . . . . . . . . . . . . 167
SFR Definition 19.2. OSCICL: Internal Oscillator Calibration . . . . . . . . . . . . . . . . . . . 167
SFR Definition 19.3. OSCXCN: External Oscillator Control . . . . . . . . . . . . . . . . . . . . 171
SFR Definition 19.4. CLKMUL: Clock Multiplier Control . . . . . . . . . . . . . . . . . . . . . . . 173
SFR Definition 19.5. CLKSEL: Clock Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
SFR Definition 20.1. RTC0KEY: smaRTClock Lock and Key . . . . . . . . . . . . . . . . . . . 180
SFR Definition 20.2. RTC0ADR: smaRTClock Address . . . . . . . . . . . . . . . . . . . . . . 181
SFR Definition 20.3. RTC0DAT: smaRTClock Data . . . . . . . . . . . . . . . . . . . . . . . . . 182
Internal Register Definition 20.4. RTC0CN: smaRTClock Control . . . . . . . . . . . . . . . 184
Internal Register Definition 20.5. RTC0XCN: smaRTClock Oscillator Control . . . . . . 185
Internal Register Definition 20.6. CAPTUREn: smaRTClock Timer Capture . . . . . . . 186
Internal Register Definition 20.7. ALARMn: smaRTClock Alarm . . . . . . . . . . . . . . . . 187
Internal Register Definition 20.8. RAMADDR: smaRTClock Backup RAM Address . . 187
Internal Register Definition 20.9. RAMDATA: smaRTClock Backup RAM Data . . . . . 188
SFR Definition 21.1. SMB0CF: SMBus Clock/Configuration . . . . . . . . . . . . . . . . . . . 197
SFR Definition 21.2. SMB0CN: SMBus Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
SFR Definition 21.3. SMB0DAT: SMBus Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
SFR Definition 22.1. SCON0: Serial Port 0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . 212
SFR Definition 22.2. SBUF0: Serial (UART0) Port Data Buffer . . . . . . . . . . . . . . . . . 213
16
Rev. 1.1
C8051F410/1/2/3
SFR Definition 23.1. SPI0CFG: SPI0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 223
SFR Definition 23.2. SPI0CN: SPI0 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
SFR Definition 23.3. SPI0CKR: SPI0 Clock Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
SFR Definition 23.4. SPI0DAT: SPI0 Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
SFR Definition 24.1. TCON: Timer Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
SFR Definition 24.2. TMOD: Timer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
SFR Definition 24.3. CKCON: Clock Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
SFR Definition 24.4. TL0: Timer 0 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
SFR Definition 24.5. TL1: Timer 1 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
SFR Definition 24.6. TH0: Timer 0 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
SFR Definition 24.7. TH1: Timer 1 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
SFR Definition 24.8. TMR2CN: Timer 2 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
SFR Definition 24.9. TMR2RLL: Timer 2 Reload Register Low Byte . . . . . . . . . . . . . 243
SFR Definition 24.10. TMR2RLH: Timer 2 Reload Register High Byte . . . . . . . . . . . 243
SFR Definition 24.11. TMR2L: Timer 2 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
SFR Definition 24.12. TMR2H Timer 2 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
SFR Definition 24.13. TMR3CN: Timer 3 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
SFR Definition 24.14. TMR3RLL: Timer 3 Reload Register Low Byte . . . . . . . . . . . . 248
SFR Definition 24.15. TMR3RLH: Timer 3 Reload Register High Byte . . . . . . . . . . . 248
SFR Definition 24.16. TMR3L: Timer 3 Low Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
SFR Definition 24.17. TMR3H Timer 3 High Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
SFR Definition 25.1. PCA0CN: PCA Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
SFR Definition 25.2. PCA0MD: PCA Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
SFR Definition 25.3. PCA0CPMn: PCA Capture/Compare Mode . . . . . . . . . . . . . . . 263
SFR Definition 25.4. PCA0L: PCA Counter/Timer Low Byte . . . . . . . . . . . . . . . . . . . 264
SFR Definition 25.5. PCA0H: PCA Counter/Timer High Byte . . . . . . . . . . . . . . . . . . . 264
SFR Definition 25.6. PCA0CPLn: PCA Capture Module Low Byte . . . . . . . . . . . . . . . 264
SFR Definition 25.7. PCA0CPHn: PCA Capture Module High Byte . . . . . . . . . . . . . . 264
C2 Register Definition 26.1. C2ADD: C2 Address . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
C2 Register Definition 26.2. DEVICEID: C2 Device ID . . . . . . . . . . . . . . . . . . . . . . . . 265
C2 Register Definition 26.3. REVID: C2 Revision ID . . . . . . . . . . . . . . . . . . . . . . . . . 266
C2 Register Definition 26.4. FPCTL: C2 Flash Programming Control . . . . . . . . . . . . 266
C2 Register Definition 26.5. FPDAT: C2 Flash Programming Data . . . . . . . . . . . . . . 266
Rev. 1.1
17
C8051F410/1/2/3
NOTES:
18
Rev. 1.1
C8051F410/1/2/3
1.
System Overview
C8051F41x devices are fully integrated, low power, mixed-signal system-on-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 50 MIPS)
In-system, full-speed, non-intrusive debug interface (on-chip)
True 12-bit 200 ksps ADC with analog multiplexer and 24 analog inputs
Two 12-bit Current Output DACs
Precision programmable 24.5 MHz internal oscillator
Up to 32 kB bytes of on-chip Flash memory
2304 bytes of on-chip RAM
SMBus/I2C, Enhanced UART, and SPI serial interfaces implemented in hardware
Four general-purpose 16-bit timers
Programmable Counter/Timer Array (PCA) with six capture/compare modules and Watchdog Timer
function
Hardware smaRTClock (Real Time Clock) operates down to 1 V with 64 bytes of Backup RAM and a
Backup Voltage Regulator
Hardware CRC Engine
On-chip Power-On Reset, VDD Monitor, and Temperature Sensor
On-chip Voltage Comparators
Up to 24 Port I/O
With on-chip Power-On Reset, VDD monitor, Watchdog Timer, and clock oscillator, the C8051F41x devices
are truly standalone system-on-a-chip solutions. The Flash memory can be reprogrammed even 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 2.0-to-2.75 V operation (supply voltage can be up to 5.25 V using on-chip regulator) over the industrial temperature range (–45 to +85 °C). The C8051F41x are available in 28-pin QFN
(also referred to as MLP or MLF) or 32-pin LQFP packages.
Rev. 1.1
19
Clock Multiplier
SMBus/I2C
SPI
UART
Timers (16-bit)
Programmable Counter Array
Port I/Os
12-bit ADC ±1 LSB INL
smaRTClock (Real Time Clock)
Two 12-bit Current Output DACs
Internal Voltage Reference
Temperature Sensor
Analog Comparators
Lead-Free (RoHS compliant)
C8051F410-GQ 50 32 kB 2368 




4

24






 LQFP-32
C8051F411-GM 50 32 kB 2368 




4

20







C8051F412-GQ 50 16 kB 2368 




4

24






 LQFP-32
C8051F413-GM 50 16 kB 2368 




4

20







20
Rev. 1.1
Package
RAM
Flash Memory
MIPS (Peak)
Calibrated Internal 24.5 MHz Oscillator
Ordering Part Number
C8051F410/1/2/3
Table 1.1. Product Selection Guide
QFN-28
QFN-28
C8051F410/1/2/3
VREGIN
VIO
(to rest of chip)
VREG
VDD
(to smarRTClock Block)
VRTC-BACKUP
Battery Switch-Over Circuit
(VDD >= VRTC-BACKUP)
GND
Port 0
Latch
P
0
Port 1
Latch
D
r
v
UART
C2D
Debug HW
Reset
/RST/C2CK
POR
XTAL1
XTAL2
External
Oscillator
Circuit
BrownOut
Clock
Mult.
32 KHz
Oscillator
32 kB
FLASH
C
R
O
S
S
B
A
R
Timer
0,1,2,3
256 B
SRAM
PCA x6 /
WDT
2 kB
XRAM
D
r
v
P
2
SPI
D
r
v
Port 2
Latch
12-bit
IDAC0
IDAC0
12-bit
IDAC1
IDAC1
CP0
CP1
64B RAM
VREF
smaRTClock
State
Machine
P
1
SMBus
C
o SFR Bus
r
CRC
e
Engine
24.5 MHz
2% Oscillator
XTAL3
XTAL4
8
0
5
1
x16
P1.0/XTAL1
P1.1/XTAL2
P1.2/VREF
P1.3
P1.4
P1.5
P1.6
P1.7
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7/C2D
+
+
-
VDD
Temp
12-bit
200 ksps
ADC
smaRTClock Alarm
P0.0/IDAC0
P0.1/IDAC1
P0.2
P0.3
P0.4/TX
P0.5/RX
P0.6/CNVST
P0.7
A
M
U
X
AIN0-AIN23
smaRTClock Block
Figure 1.1. C8051F410 Block Diagram
Rev. 1.1
21
C8051F410/1/2/3
VREGIN
VIO
(to rest of chip)
VREG
VDD
(to smaRTClock Block)
VRTC-BACKUP
Battery Switch-Over Circuit
(VDD >= VRTC-BACKUP)
GND
Port 0
Latch
P
0
Port 1
Latch
D
r
v
UART
C2D
Debug HW
Reset
/RST/C2CK
POR
XTAL1
XTAL2
External
Oscillator
Circuit
BrownOut
Clock
Mult.
32 KHz
Oscillator
32 kB
FLASH
C
R
O
S
S
B
A
R
Timer
0,1,2,3
256 B
SRAM
PCA x6 /
WDT
2 kB
XRAM
VREF
smaRTClock Alarm
12-bit
IDAC0
IDAC0
12-bit
IDAC1
IDAC1
CP0
CP1
D
r
v
P2.7/C2D
+
+
-
Temp
12-bit
200 ksps
ADC
Figure 1.2. C8051F411 Block Diagram
Rev. 1.1
P2.0
P2.1
P2.2
VDD
smaRTClock Block
22
P
2
SPI
Port 2
Latch
64B RAM
smaRTClock
State
Machine
D
r
v
P1.0/XTAL1
P1.1/XTAL2
P1.2/VREF
P1.3
P1.4
P1.5
P1.6
P1.7
P
1
SMBus
C
o SFR Bus
r
CRC
e
Engine
24.5 MHz
2% Oscillator
XTAL3
XTAL4
8
0
5
1
x16
A
M
U
X
P0.0/IDAC0
P0.1/IDAC1
P0.2
P0.3
P0.4/TX
P0.5/RX
P0.6/CNVST
P0.7
AIN0-AIN20
C8051F410/1/2/3
VREGIN
VIO
(to rest of chip)
VREG
VDD
(to smaRTClocl Block)
VRTC-BACKUP
Battery Switch-Over Circuit
(VDD >= VRTC-BACKUP)
GND
Port 0
Latch
P
0
Port 1
Latch
D
r
v
UART
C2D
Debug HW
Reset
/RST/C2CK
POR
XTAL1
XTAL2
External
Oscillator
Circuit
BrownOut
Clock
Mult.
32 KHz
Oscillator
x16
16 kB
FLASH
C
R
O
S
S
B
A
R
Timer
0,1,2,3
256 B
SRAM
PCA x6 /
WDT
2 kB
XRAM
D
r
v
P
2
SPI
D
r
v
Port 2
Latch
12-bit
IDAC0
IDAC0
12-bit
IDAC1
IDAC1
CP0
CP1
64B RAM
VREF
smaRTClock
State
Machine
P
1
SMBus
C
o SFR Bus
r
CRC
e
Engine
24.5 MHz
2% Oscillator
XTAL3
XTAL4
8
0
5
1
P1.0/XTAL1
P1.1/XTAL2
P1.2/VREF
P1.3
P1.4
P1.5
P1.6
P1.7
P2.0
P2.1
P2.2
P2.3
P2.4
P2.5
P2.6
P2.7/C2D
+
+
-
VDD
Temp
12-bit
200 ksps
ADC
smaRTClock Alarm
P0.0/IDAC0
P0.1/IDAC1
P0.2
P0.3
P0.4/TX
P0.5/RX
P0.6/CNVST
P0.7
A
M
U
X
AIN0-AIN23
smaRTClock Block
Figure 1.3. C8051F412 Block Diagram
Rev. 1.1
23
C8051F410/1/2/3
VREGIN
VIO
(to rest of chip)
VREG
VDD
(to smaRTClock Block)
VRTC-BACKUP
Battery Switch-Over Circuit
(VDD >= VRTC-BACKUP)
GND
Port 0
Latch
P
0
Port 1
Latch
D
r
v
UART
C2D
Debug HW
Reset
/RST/C2CK
POR
XTAL1
XTAL2
External
Oscillator
Circuit
BrownOut
Clock
Mult.
32 KHz
Oscillator
16 kB
FLASH
C
R
O
S
S
B
A
R
Timer
0,1,2,3
256 B
SRAM
PCA x6 /
WDT
2 kB
XRAM
VREF
smaRTClock Alarm
12-bit
IDAC0
IDAC0
12-bit
IDAC1
IDAC1
CP0
CP1
D
r
v
P2.7/C2D
+
+
-
Temp
12-bit
200 ksps
ADC
Figure 1.4. C8051F413 Block Diagram
Rev. 1.1
P2.0
P2.1
P2.2
VDD
smaRTClock Block
24
P
2
SPI
Port 2
Latch
64B RAM
smaRTClock
State
Machine
D
r
v
P1.0/XTAL1
P1.1/XTAL2
P1.2/VREF
P1.3
P1.4
P1.5
P1.6
P1.7
P
1
SMBus
C
o SFR Bus
r
CRC
e
Engine
24.5 MHz
2% Oscillator
XTAL3
XTAL4
8
0
5
1
x16
A
M
U
X
P0.0/IDAC0
P0.1/IDAC1
P0.2
P0.3
P0.4/TX
P0.5/RX
P0.6/CNVST
P0.7
AIN0-AIN20
C8051F410/1/2/3
1.1.
CIP-51™ Microcontroller
1.1.1. Fully 8051 Compatible Instruction Set
The C8051F41x devices use Silicon Laboratories’ proprietary CIP-51 microcontroller core. 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 C8051F41x family 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 50 MHz, it has a peak throughput of 50 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 C8051F41x SoC 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 Comparator0, a smaRTClock alarm or
missing smaRTClock clock detector reset, 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 ±2%. 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. A clock multiplier allows for operation at up to 50 MHz. The dedicated smaRTClock oscillator can be extremely useful in low power applications, allowing the system to maintain accurate time
while the MCU is not powered, or its internal oscillator is suspended. The MCU can be reset or have its
oscillator awakened using the smaRTClock alarm function.
Rev. 1.1
25
C8051F410/1/2/3
1.2.
On-Chip Debug Circuitry
The C8051F41x 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 debugging. All the peripherals (except for the ADC and SMBus) are stalled when the MCU is halted, during single
stepping, or at a breakpoint in order to keep them synchronized.
The C8051F410DK development kit provides all the hardware and software necessary to develop application code and perform in-circuit debugging with the C8051F41x 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®98 SE or later installed. As shown in Figure 1.5, 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.
Silicon Laboratories Integrated
Development Environment
WINDOWS 98 SE or later
USB
Debug
Adapter
C2 (x2), GND
VDD GND
TARGET PCB
C8051F41x
Figure 1.5. Development/In-System Debug Diagram
26
Rev. 1.1
C8051F410/1/2/3
1.3.
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 32 kB (‘F410/1) or 16 kB (‘F412/3) of Flash. This memory may be reprogrammed in-system in 512 byte sectors and requires no special off-chip programming voltage.
PROGRAM/DATA MEMORY
(Flash)
DATA MEMORY (RAM)
INTERNAL DATA ADDRESS SPACE
‘F410/1
0xFF
0x7E00
RESERVED
0x7DFF
0x80
0x7F
Upper 128 RAM
(Indirect Addressing
Only)
(Direct and Indirect
Addressing)
32 kB Flash
(In-System
Programmable in 512
Byte Sectors)
0x0000
0x20
0x1F
0x00
Bit Addressable
General Purpose
Registers
0xFFFF
RESERVED
Same 2048 bytes as from
0x0000 to 0x07FF, wrapped
on 2048-byte boundaries
0x3FFF
16 kB Flash
(In-System
Programmable in 512
Byte Sectors)
0x0000
Lower 128 RAM
(Direct and Indirect
Addressing)
EXTERNAL DATA ADDRESS SPACE
‘F412/3
0x4000
0x30
0x2F
Special Function
Register's
(Direct Addressing Only)
0x0800
0x07FF
XRAM - 2048 Bytes
(accessible using MOVX
instruction)
0x0000
Figure 1.6. Memory Map
Rev. 1.1
27
C8051F410/1/2/3
1.4.
Operating Modes
The C8051F41x 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. Suspend mode halts SYSCLK until a wakening event occurs, which also halts all peripherals using SYSCLK. In 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
Power
Consumption
How
Entered?
How Exited?
SYSCLK active
CPU active (accessing Flash)
Peripherals active or inactive
depending on user settings
smaRTClock active or inactive
Full
—
—
SYSCLK active
CPU inactive (not accessing
Flash)
Peripherals active or inactive
depending on user settings
smaRTClock active or inactive
Less than Full
IDLE
(PCON.0)
Any enabled
interrupt or
device reset
SYSCLK inactive
CPU inactive (not accessing
Flash)
Peripherals enabled (but not
operating) or disabled depending on user settings
smaRTClock active or inactive
Low
SUSPEND
(OSCICN.5)
Wakening
event or external/MCD reset
SYSCLK inactive
CPU inactive (not accessing
Flash)
Digital peripherals inactive;
analog peripherals enabled
(but not operating) or disabled
depending on user settings
smaRTClock inactive
Very low
STOP
(PCON.1)
External or
MCD reset
Properties
Active
•
•
•
•
•
•
Idle
•
•
•
•
Suspend
•
•
•
•
Stop
•
•
See Section “10.3. Power Management Modes” on page 101 for Idle and Stop mode details. See Section “19.1.1. Internal Oscillator Suspend Mode” on page 166 for more information on Suspend mode.
28
Rev. 1.1
C8051F410/1/2/3
1.5.
12-Bit Analog to Digital Converter
The C8051F41x devices include an on-chip 12-bit SAR ADC with a 27-channel single-ended input multiplexer and 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 0–2 are available
as ADC inputs; additionally, the on-chip Temperature Sensor output and the core supply voltage (VDD) are
available as ADC inputs. User firmware may shut down the ADC or use it in Burst Mode to save power.
Conversions can be started in four ways: a software command, an overflow of Timer 2 or 3, 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 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
P0.7
P1.0
P1.7
P2.0
P2.3-2.6
available on
C8051F410/2
Temp
Sensor
Burst Mode
Logic
AD0BUSY (W)
Timer 3 Overflow
CNVSTR Rising Edge
Timer 2 Overflow
19-to-1
AMUX
12-Bit
SAR
ADC
P2.7
VDD
GND
End of
Conversion
Interrupt
16
ADC Data
Registers
Accumulator
Window Compare
Logic
Window
Compare
Interrupt
Figure 1.7. 12-Bit ADC Block Diagram
1.6.
Two 12-bit Current-Mode DACs
The C8051F41x devices include two 12-bit current-mode Digital-to-Analog Converters (IDACs). The maximum current output of the IDACs can be adjusted for four different current settings; 0.25 mA, 0.5 mA,
1 mA, and 2 mA. A flexible output update mechanism allows for seamless full-scale changes, and supports
jitter-free updates for waveform generation. The IDAC outputs can be merged onto a single port I/O pin for
increased full-scale current output or increased resolution. IDAC updates can be performed on-demand,
scheduled on a Timer overflow, or synchronized with an external signal. Figure 1.8 shows a block diagram
of the IDAC circuitry.
Rev. 1.1
29
C8051F410/1/2/3
12-bit Digital 12
Input
Latch
12
12-bit Digital 12
Input
Latch
Data Write
Timer 0
Timer 1
Timer 2
Timer 3
CNVSTR
12
IDA0
Current
Output
IDA1
Current
Output
Data Write
Timer 0
Timer 1
Timer 2
Timer 3
CNVSTR
Figure 1.8. IDAC Block Diagram
1.7.
Programmable Comparators
C8051F41x devices include two software-configurable voltage comparators with an input multiplexer. Each
comparator offers programmable response time and hysteresis and two outputs that are optionally available at the Port pins: a synchronous “latched” output (CP0 and CP1), or an asynchronous “raw” output
(CP0A and CP1A). Comparator interrupts 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. Comparator0 may also be configured as a reset source. A block diagram of the comparator is shown in Figure 1.9.
30
Rev. 1.1
C8051F410/1/2/3
VDD
Port I/O
Pins
Multiplexer
Interrupt
Logic
+
D
-
SET
CLR
Q
D
Q
SET
CLR
Q
CP0
(synchronous output)
Q
(SYNCHRONIZER)
CP0A
(asynchronous output)
GND
Reset
Decision
Tree
VDD
Port I/O
Pins
Multiplexer
Interrupt
Logic
+
D
-
SET
CLR
Q
Q
D
SET
CLR
Q
CP1
(synchronous output)
Q
(SYNCHRONIZER)
CP1A
(asynchronous output)
GND
Figure 1.9. Comparators Block Diagram
1.8.
Cyclic Redundancy Check Unit
C8051F41x devices include a cyclic redundancy check unit (CRC0) that can perform a CRC using a 16-bit
or 32-bit polynomial. CRC0 accepts a stream of 8-bit data and outputs a 16-bit or 32-bit result. CRC0 also
has a hardware bit reverse feature for quick data manipulation.
1.9.
Voltage Regulator
C8051F41x 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 2.0 V or 2.5 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.
1.10. Serial Ports
The C8051F41x Family includes an SMBus/I2C interface, 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.
Rev. 1.1
31
C8051F410/1/2/3
1.11. smaRTClock (Real Time Clock)
C8051F41x devices include a smaRTClock Peripheral (Real Time Clock). The smaRTClock has a dedicated 32 kHz oscillator that can be configured for use with or without a crystal, a 47-bit smaRTClock timer
with alarm, a backup supply regulator, and 64 bytes of backup SRAM. When the backup supply voltage
(VRTC-BACKUP) is powered, the smaRTClock peripheral remains fully functional even if the core supply voltage (VDD) is lost.
The smaRTClock allows a maximum of 137 year 47-bit independent time-keeping when used with a
32.768 kHz Watch Crystal and backup supply voltage of at least 1 V. The switchover logic powers smaRTClock from the backup supply when the voltage at VRTC-BACKUP is greater than VDD. The smaRTClock
alarm and missing clock detector can interrupt the CIP-51, wake the internal oscillator from SUSPEND
mode, or generate a device reset if the smaRTClock timer reaches a pre-set value or the oscillator stops.
XTAL3
XTAL4
smaRTClock
smaRTClock Oscillator
smaRTClock State Machine
Interrupt
64B
Backup RAM
Backup
Regulator
Switchover
Logic
Internal
Registers
Interface
Registers
CAPTUREn
RTC0CN
RTC0XCN
ALARMn
RAMADDR
RAMDATA
RTC0KEY
CIP-51 CPU
47-Bit
smaRTClock
Timer
RTC0ADR
RTC0DAT
VDD
VRTC-BACKUP
Figure 1.10. smaRTClock Block Diagram
32
Rev. 1.1
C8051F410/1/2/3
1.12. Port Input/Output
C8051F41x devices include up to 24 I/O pins. Port pins are organized as three 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 individually or 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
PnMDOUT,
PnMDIN Registers
Priority
Decoder
Highest
Priority
UART
4
(Internal Digital Signals)
SPI
2
SMBus
CP0
CP1
Outputs
Digital
Crossbar
8
7
T0, T1
2
8
8
(Port Latches)
P0
8
4
SYSCLK
PCA
Lowest
Priority
2
P0
I/O
Cells
P1
I/O
Cells
P2
I/O
Cell
P0.0
P0.7
P1.0
P1.7
P2.0
P2.7
P2.3–2.6 available on
C8051F410/2
(P0.0-P0.7)
8
P1
(P1.0-P1.7)
8
P2
(P2.0-P2.7)
Figure 1.11. Port I/O Functional Block Diagram
Rev. 1.1
33
C8051F410/1/2/3
1.13. Programmable Counter Array
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 six 16-bit capture/compare modules. The counter/timer is driven by a programmable timebase that
can select between seven sources: system clock, system clock divided by four, system clock divided by
twelve, the external oscillator clock source divided by 8, real-time clock source divided by 8, Timer 0 overflow, or an external clock signal on the External Clock Input (ECI) pin.
Each capture/compare module may be configured to operate independently in one of six modes: EdgeTriggered Capture, Software Timer, High-Speed Output, Frequency Output, 8-Bit PWM, or 16-Bit PWM.
Additionally, PCA Module 5 may be used as a watchdog timer (WDT), and is enabled in this mode following a system reset. The PCA Capture/Compare Module I/O and the External Clock Input may be routed to
Port I/O using the digital crossbar.
SYSCLK/12
SYSCLK/4
Timer 0 Overflow
ECI
SYSCLK
PCA
CLOCK
MUX
16-Bit Counter/Timer
External Clock/8
smaRTClock/8
Capture/Compare
Module 0
Capture/Compare
Module 1
Capture/Compare
Module 2
Capture/Compare
Module 3
Figure 1.12. PCA Block Diagram
34
Rev. 1.1
Capture/Compare
Module 5
CEX5
Port I/O
CEX4
CEX3
CEX2
CEX1
CEX0
ECI
Crossbar
Capture/Compare
Module 4
C8051F410/1/2/3
2.
Absolute Maximum Ratings
Table 2.1. Absolute Maximum Ratings*
Parameter
Conditions
Min
Typ
Max
Units
Ambient temperature under bias
–55
—
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
—
3.0
V
Voltage on VRTC-BACKUP with respect to GND
–0.3
—
5.5
V
Voltage on XTAL1 with respect to GND
–0.3
—
VDD+ 0.3
V
Voltage on XTAL3 with respect to GND
–0.3
—
5.5
V
Voltage on any Port I/O Pin (except Port 0 pins) or
RST with respect to GND
–0.3
—
VIO + 0.3
V
Voltage on any Port 0 Pin with respect to GND
0.3
—
5.5
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 VDD, VIO,
VRTC-BACKUP, 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. 1.1
35
C8051F410/1/2/3
3.
Global DC Electrical Characteristics
Table 3.1. Global DC Electrical Characteristics
–40 to +85 °C, 50 MHz System Clock unless otherwise specified. Typical values are given at 25 °C
Parameter
Conditions
Min
Typ
Max
Units
Output Current = 1 mA
2.15
—
5.25
V
Core Supply Voltage (VDD)
2.0
—
2.75
V
I/O Supply Voltage (VIO)2
2.0
—
5.25
V
Backup Supply Voltage (VRTC-BACKUP)3
1.0
—
5.25
V
—
—
—
0.65
0.9
1.4
1.5
1.8
2.5
µA
µA
µA
—
—
—
0.7
0.92
1.45
—
—
—
µA
µA
µA
—
—
—
0.72
0.95
1.5
1.6
1.85
2.6
µA
µA
µA
Core Supply RAM Data Retention Voltage
—
1.5
—
V
SYSCLK (System Clock)4,5
0
—
50
MHz
–40
—
+85
°C
Supply Input Voltage (VREGIN)1
Backup Supply Current
(IRTC-BACKUP)
(VDD = 0 V, smaRTClock clock = 32 kHz)
VRTC-BACKUP = 1.0 V:
at –40 ºC
at 25 ºC
at 85 ºC
VRTC-BACKUP = 1.8 V:
at –40 ºC
at 25 ºC
at 85 ºC
VRTC-BACKUP = 2.5 V:
at –40 ºC
at 25 ºC
at 85 ºC
Specified Operating Temperature Range
Notes:
1. For more information on VREGIN characteristics, see Table 8.1 on page 82.
2. VIO must be equal to or greater than VDD.
3. The Backup Supply Voltage (VRTC-BACKUP) is used to power the smaRTClock peripheral only.
4. SYSCLK is the internal device clock. For operational speeds in excess of 25 MHz, SYSCLK must
be derived from the internal clock multiplier.
5. SYSCLK must be at least 32 kHz to enable debugging.
6. Based on device characterization data, not production tested.
7. Active and Inactive IDD at voltages and frequencies other than those specified can be calculated
using the IDD Supply Sensitivity. For example, if the VDD is 2.2 V instead of 2.0 V at 25 MHz:
IDD = 5.5 mA typical at 2.0 V and f = 25 MHz. From this, IDD = 5.5 mA + 1.14 x
(2.2 V – 2.0 V) = 5.73 mA at 2.2 V and f = 25 MHz.
8. IDD can be estimated for frequencies < 15 MHz by simply multiplying the frequency of interest by the
frequency sensitivity number for that range. When using these numbers to estimate IDD for >
15 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by
the frequency sensitivity number. For example: VDD = 2.0 V; F = 20 MHz,
IDD = 5.5 mA – (25 MHz – 20 MHz) x 0.16 mA/MHz = 4.7 mA.
9. Idle IDD can be estimated for frequencies < 1 MHz by simply multiplying the frequency of interest by
the frequency sensitivity number for that range. When using these numbers to estimate Idle for >
1 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by
the frequency sensitivity number. For example: VDD = 2.0 V; F = 5 MHz, Idle
IDD = 2.8 mA – (25 MHz – 5 MHz) x 0.1 mA/MHz = 0.8 mA.
36
Rev. 1.1
C8051F410/1/2/3
Table 3.1. Global DC Electrical Characteristics (Continued)
–40 to +85 °C, 50 MHz System Clock unless otherwise specified. Typical values are given at 25 °C
Parameter
Conditions
Min
Typ
Max
Units
Digital Supply Current—CPU Active (Normal Mode, fetching instructions from Flash)
Core Supply Current (IDD)6
Supply Sensitivity (IDD)6,7
Frequency Sensitivity (IDD)6,8
VDD = 2.0 V:
F = 32 kHz
F = 1 MHz
F = 25 MHz
F = 50 MHz
VDD = 2.5 V:
F = 32 kHz
F = 1 MHz
F = 25 MHz
F = 50 MHz
F = 25 MHz
F = 1 MHz
VDD = 2.0 V:
F < 15 MHz, T = 25 ºC
F > 15 MHz, T = 25 ºC
VDD = 2.5 V:
F < 15 MHz, T = 25 ºC
F > 15 MHz, T = 25 ºC
—
—
—
—
13
0.30
5.5
9.5
30
0.5
6.5
12
µA
mA
mA
mA
—
—
—
—
17
0.43
8.3
13.5
40
0.65
9.5
15
µA
mA
mA
mA
—
—
114
100
—
—
%/V
%/V
—
—
0.27
0.16
—
—
mA/MHz
mA/MHz
—
—
0.39
0.2
—
—
mA/MHz
mA/MHz
Notes:
1. For more information on VREGIN characteristics, see Table 8.1 on page 82.
2. VIO must be equal to or greater than VDD.
3. The Backup Supply Voltage (VRTC-BACKUP) is used to power the smaRTClock peripheral only.
4. SYSCLK is the internal device clock. For operational speeds in excess of 25 MHz, SYSCLK must
be derived from the internal clock multiplier.
5. SYSCLK must be at least 32 kHz to enable debugging.
6. Based on device characterization data, not production tested.
7. Active and Inactive IDD at voltages and frequencies other than those specified can be calculated
using the IDD Supply Sensitivity. For example, if the VDD is 2.2 V instead of 2.0 V at 25 MHz:
IDD = 5.5 mA typical at 2.0 V and f = 25 MHz. From this, IDD = 5.5 mA + 1.14 x
(2.2 V – 2.0 V) = 5.73 mA at 2.2 V and f = 25 MHz.
8. IDD can be estimated for frequencies < 15 MHz by simply multiplying the frequency of interest by the
frequency sensitivity number for that range. When using these numbers to estimate IDD for >
15 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by
the frequency sensitivity number. For example: VDD = 2.0 V; F = 20 MHz,
IDD = 5.5 mA – (25 MHz – 20 MHz) x 0.16 mA/MHz = 4.7 mA.
9. Idle IDD can be estimated for frequencies < 1 MHz by simply multiplying the frequency of interest by
the frequency sensitivity number for that range. When using these numbers to estimate Idle for >
1 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by
the frequency sensitivity number. For example: VDD = 2.0 V; F = 5 MHz, Idle
IDD = 2.8 mA – (25 MHz – 5 MHz) x 0.1 mA/MHz = 0.8 mA.
Rev. 1.1
37
C8051F410/1/2/3
Table 3.1. Global DC Electrical Characteristics (Continued)
–40 to +85 °C, 50 MHz System Clock unless otherwise specified. Typical values are given at 25 °C
Parameter
Conditions
Min
Typ
Max
Units
Digital Supply Current—CPU Inactive (Idle Mode, not fetching instructions from Flash)
Core Supply Current (IDD)6
Supply Sensitivity (IDD)6,7
Frequency Sensitivity (IDD)6,9
VDD = 2.0 V:
F = 32 kHz
F = 1 MHz
F = 25 MHz
F = 50 MHz
VDD = 2.5 V:
F = 32 kHz
F = 1 MHz
F = 25 MHz
F = 50 MHz
F = 25 MHz
F = 1 MHz
VDD = 2.0 V:
F < 1 MHz, T = 25 ºC
F > 1 MHz, T = 25 ºC
VDD = 2.5 V:
F < 1 MHz, T = 25 ºC
F > 1 MHz, T = 25 ºC
—
—
—
—
10
0.15
2.8
5
25
0.25
3.3
11
µA
mA
mA
mA
—
—
—
—
11
0.21
3.8
7.5
30
0.37
4.3
8.0
µA
mA
mA
mA
—
—
75
68
—
—
%/V
%/V
—
—
0.14
0.1
—
—
mA/MHz
mA/MHz
—
—
0.19
0.13
—
—
mA/MHz
mA/MHz
Digital Supply Current (Suspend Mode)
Oscillator not running,
VDD = 2.5 V
—
0.15
50
µA
Digital Supply Current
(Stop Mode, shutdown)
Oscillator not running,
VDD = 2.5 V
—
0.15
50
µA
Notes:
1. For more information on VREGIN characteristics, see Table 8.1 on page 82.
2. VIO must be equal to or greater than VDD.
3. The Backup Supply Voltage (VRTC-BACKUP) is used to power the smaRTClock peripheral only.
4. SYSCLK is the internal device clock. For operational speeds in excess of 25 MHz, SYSCLK must
be derived from the internal clock multiplier.
5. SYSCLK must be at least 32 kHz to enable debugging.
6. Based on device characterization data, not production tested.
7. Active and Inactive IDD at voltages and frequencies other than those specified can be calculated
using the IDD Supply Sensitivity. For example, if the VDD is 2.2 V instead of 2.0 V at 25 MHz:
IDD = 5.5 mA typical at 2.0 V and f = 25 MHz. From this, IDD = 5.5 mA + 1.14 x
(2.2 V – 2.0 V) = 5.73 mA at 2.2 V and f = 25 MHz.
8. IDD can be estimated for frequencies < 15 MHz by simply multiplying the frequency of interest by the
frequency sensitivity number for that range. When using these numbers to estimate IDD for >
15 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by
the frequency sensitivity number. For example: VDD = 2.0 V; F = 20 MHz,
IDD = 5.5 mA – (25 MHz – 20 MHz) x 0.16 mA/MHz = 4.7 mA.
9. Idle IDD can be estimated for frequencies < 1 MHz by simply multiplying the frequency of interest by
the frequency sensitivity number for that range. When using these numbers to estimate Idle for >
1 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by
the frequency sensitivity number. For example: VDD = 2.0 V; F = 5 MHz, Idle
IDD = 2.8 mA – (25 MHz – 5 MHz) x 0.1 mA/MHz = 0.8 mA.
38
Rev. 1.1
C8051F410/1/2/3
Table 3.2. Index to Electrical Characteristics Tables
Table Title
Page #
ADC0 Electrical Characteristics (VDD = 2.5 V, VREF = 2.2 V)
67
ADC0 Electrical Characteristics (VDD = 2.1 V, VREF = 1.5 V)
68
IDAC Electrical Characteristics
75
Voltage Reference Electrical Characteristics
79
Voltage Regulator Electrical Specifications
82
Comparator Electrical Characteristics
92
Reset Electrical Characteristics
134
Flash Electrical Characteristics
143
Port I/O DC Electrical Characteristics
163
Oscillator Electrical Characteristics
175
Rev. 1.1
39
C8051F410/1/2/3
NOTES:
40
Rev. 1.1
C8051F410/1/2/3
4.
Pinout and Package Definitions
Table 4.1. Pin Definitions for the C8051F41x
Name
Pin Numbers
Type
Description
‘F410/2
‘F411/3
VDD
7
6
Core Supply Voltage.
VIO
1
28
I/O Supply Voltage.
GND
6
5
Ground.
VRTC-BACKUP
3
2
smaRTClock Backup Supply Voltage.
VREGIN
8
7
On-Chip Voltage Regulator Input.
RST/
2
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 VIO is
recommended. See Reset Sources Section for a complete
description.
D I/O
Clock signal for the C2 Debug Interface.
D I/O
Port 2.7. See Port I/O Section for a complete description.
D I/O
Bi-directional data signal for the C2 Debug Interface.
1
C2CK
P2.7/
32
D I/O
27
C2D
XTAL3
5
4
A In
smaRTClock Oscillator Crystal Input.
See Section 20. "smaRTClock (Real Time Clock)" for a
complete description.
XTAL4
4
3
A Out
smaRTClock Oscillator Crystal Input.
See Section 20. "smaRTClock (Real Time Clock)" for a
complete description.
P0.0/
17
16
IDAC0
A Out
P0.1/
17
IDAC1
P0.3
IDAC0 Output. See IDAC Section for complete description.
D I/O or Port 0.1. See Port I/O Section for a complete description.
A In
18
P0.2
D I/O or Port 0.0. See Port I/O Section for a complete description.
A In
A Out
IDAC1 Output. See IDAC Section for complete description.
19
18
D I/O or Port 0.2. See Port I/O Section for a complete description.
A In
20
19
D I/O or Port 0.3. See Port I/O Section for a complete description.
A In
Rev. 1.1
41
C8051F410/1/2/3
Table 4.1. Pin Definitions for the C8051F41x (Continued)
Name
Pin Numbers
‘F410/2
‘F411/3
Description
D I/O or Port 0.4. See Port I/O Section for a complete description.
A In
P0.4/
21
20
D Out
TX
P0.5/
UART TX Pin. See Port I/O Section for a complete description.
D I/O or Port 0.5. See Port I/O Section for a complete description.
A In
22
21
RX
D In
P0.6/
UART RX Pin. See Port I/O Section for a complete description.
D I/O or Port 0.6. See Port I/O Section for a complete description.
A In
23
22
CNVSTR
P0.7
Type
D In
24
23
D I/O or Port 0.7. See Port I/O Section for a complete description.
A In
8
D I/O or Port 1.0. See Port I/O Section for a complete description.
A In
External Clock Input. This pin is the external oscillator
A In
return for a crystal or resonator. See Oscillator Section.
P1.0/
9
External Convert Start Input for ADC0, IDA0, and IDA1. See
ADC0 or IDACs section for a complete description.
XTAL1
Port 1.1. See Port I/O Section for a complete description.
D I/O or
A In
P1.1/
10
9
A O or
D In
XTAL2
P1.2
11
10
VREF
42
External Clock Output. This pin is the excitation driver for an
external crystal or resonator, or an external clock input for
CMOS, capacitor, or RC oscillator configurations. See
Oscillator Section.
D I/O or Port 1.2. See Port I/O Section for a complete description.
A In
A In
External VREF Input. See VREF Section.
P1.3
12
11
D I/O or Port 1.3. See Port I/O Section for a complete description.
A In
P1.4
13
12
D I/O or Port 1.4. See Port I/O Section for a complete description.
A In
P1.5
14
13
D I/O or Port 1.5. See Port I/O Section for a complete description.
A In
P1.6
15
14
D I/O or Port 1.6. See Port I/O Section for a complete description.
A In
Rev. 1.1
C8051F410/1/2/3
Table 4.1. Pin Definitions for the C8051F41x (Continued)
Name
Pin Numbers
Type
Description
‘F410/2
‘F411/3
P1.7
16
15
D I/O or Port 1.7. See Port I/O Section for a complete description.
A In
P2.0
25
24
D I/O or Port 2.0. See Port I/O Section for a complete description.
A In
P2.1
26
25
D I/O or Port 2.1. See Port I/O Section for a complete description.
A In
P2.2
27
26
D I/O or Port 2.2. See Port I/O Section for a complete description.
A In
P2.3*
28
D I/O or Port 2.3. See Port I/O Section for a complete description.
A In
P2.4*
29
D I/O or Port 2.4. See Port I/O Section for a complete description.
A In
P2.5*
30
D I/O or Port 2.5. See Port I/O Section for a complete description.
A In
P2.6*
31
D I/O or Port 2.6. See Port I/O Section for a complete description.
A In
*Note: Available only on the C8051F410/2.
Rev. 1.1
43
P2.7 / C2D
P2.6
P2.5
P2.4
P2.3
P2.2
P2.1
P2.0
32
31
30
29
28
27
26
25
C8051F410/1/2/3
V IO
1
24
P0.7
RST/C2CK
2
23
P0.6 / CNVSTR
V RTC-BACKUP
3
22
P0.5 / RX
XTAL4
4
21
P0.4 / TX
XTAL3
5
20
P0.3
GND
6
19
P0.2
V DD
7
18
P0.1 / IDAC1
V REGIN
8
17
P0.0 / IDAC0
14
15
16
P1.6
P1.7
12
P1.3
P1.5
11
P1.2 / VREF
13
10
P1.1 / XTAL2
P1.4
9
P1.0 / XTAL1
C8051F410/2
Top View
Figure 4.1. LQFP-32 Pinout Diagram (Top View)
44
Rev. 1.1
VIO
P2.7 / C2D
P2.2
P2.1
P2.0
P0.7
P0.6 / CNVSTR
28
27
26
25
24
23
22
C8051F410/1/2/3
RST / C2CK
1
21
P0.5 / RX
V RTC-BACKUP
2
20
P0.4 / TX
XTAL4
3
19
P0.3
XTAL3
4
18
P0.2
GND
5
17
P0.1 / IDAC1
V DD
6
16
P0.0 / IDAC0
V REGIN
7
15
P1.7
C8051F411/3
Top View
8
9
10
11
12
13
14
P1.0 / XTAL1
P1.1 / XTAL2
P1.2 / VREF
P1.3
P1.4
P1.5
P1.6
GND
Figure 4.2. QFN-28 Pinout Diagram (Top View)
Rev. 1.1
45
C8051F410/1/2/3
Figure 4.3. LQFP-32 Package Diagram
Table 4.2. LQFP-32 Package Dimensions
A
A1
A2
b
c
D
D1
e
E
E1
L
46
MM
TYP
—
—
1.40
0.37
—
9.00
7.00
0.80
9.00
7.00
0.60
MIN
—
0.05
1.35
0.30
0.09
—
—
—
—
—
0.45
Rev. 1.1
MAX
1.60
0.15
1.45
0.45
0.20
—
—
—
—
—
0.75
C8051F410/1/2/3
Figure 4.4. LQFP-32 Recommended PCB Land Pattern
Table 4.3. LQFP-32 PCB Land Pattern Dimensions
Dimension
Min
Max
C1
8.40
8.50
C2
8.40
8.50
E
0.80 BSC
X1
0.40
0.50
Y1
1.25
1.35
Rev. 1.1
47
C8051F410/1/2/3
Figure 4.5. QFN-28 Package Drawing
Table 4.4. QFN-28 Package Dimensions
Dimension
Min
Typ
Max
Dimension
Min
Typ
Max
A
A1
A3
b
D
D2
e
E
E2
0.80
0.00
0.90
0.02
0.25 REF
0.23
5.00 BSC.
3.15
0.50 BSC.
5.00 BSC.
3.15
1.00
0.05
L
L1
aaa
bbb
ddd
eee
Z
Y
0.35
0.00
0.55
—
0.15
0.10
0.05
0.08
0.44
0.18
0.65
0.15
0.18
2.90
2.90
0.30
3.35
3.35
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 the JEDEC Solid State Outline MO-220, variation VHHD except for
custom features D2, E2, Z, Y, 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.
48
Rev. 1.1
C8051F410/1/2/3
Figure 4.6. QFN-28 Recommended PCB Land Pattern
Table 4.5. QFN-28 PCB Land Pattern Dimensions
Dimension
C1
C2
E
X1
Min
Max
4.80
4.80
0.50
0.20
Dimension
Min
Max
X2
Y1
Y2
3.20
0.85
3.20
3.30
0.95
3.30
0.30
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing is per the ANSI Y14.5M-1994 specification.
3. This Land Pattern Design is based on the IPC-7351 guidelines.
Solder Mask Design
4. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder
mask and the metal pad is to be 60μm minimum, all the way around the pad.
Stencil Design
5. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used
to assure good solder paste release.
6. The stencil thickness should be 0.125mm (5 mils).
7. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pins.
8. A 3x3 array of 0.90mm openings on a 1.1mm pitch should be used for the center pad to
assure the proper paste volume (67% Paste Coverage).
Card Assembly
9. A No-Clean, Type-3 solder paste is recommended.
10. The recommended card reflow profile is per the JEDEC/IPC J-STD-020C specification for
Small Body Components.
Rev. 1.1
49
C8051F410/1/2/3
NOTES:
50
Rev. 1.1
C8051F410/1/2/3
5.
12-Bit ADC (ADC0)
The ADC0 subsystem for the C8051F41x consists of an analog multiplexer (AMUX0) with 27 total input
selections, and a 200 ksps, 12-bit successive-approximation-register ADC with integrated track-and-hold,
programmable window detector, 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.
27-to-1
AMUX
ADC
P2.7
AD0TM1:0
P2.3-P2.6 available on
‘F410/2
VDD
Timer 3 Overflow
10
CNVSTR Input
11
Timer 2 Overflow
Accumulator
AD0PRE
AD0POST
FCLK
REF
P1.7
P2.0
12-Bit
SAR
AD0BUSY (W)
01
ADC0L
Burst Mode
Oscillator
25 MHz Max
00
ADC0H
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
AD0WINT
AD0RPT1
AD0RPT0
GND
AD0SC3
AD0SC2
AD0SC1
AD0SC0
AD0SC4
Temp Sensor
ADC0CF
32
ADC0LTH ADC0LTL
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-P2.7,
the on-chip temperature sensor, the core power supply (VDD), or ground (GND). ADC0 is single-ended
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 = 0,1,2) and write a ‘1’ in the corresponding
Port Latch register Pn (for n = 0,1,2). To force the Crossbar to skip a Port pin, set to ‘1’ the corresponding
bit in register PnSKIP (for n = 0,1,2). See Section “18. Port Input/Output” on page 147 for more Port I/O
configuration details.
Rev. 1.1
51
C8051F410/1/2/3
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 = SLOPE(TEMPC) + Offset
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.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
Step 8.
52
Choose the start of conversion source.
Choose Normal Mode or Burst Mode operation.
If Burst Mode, choose the ADC0 Idle Power State and set the Power-Up Time.
Choose the tracking mode. Note that Pre-Tracking Mode can only be used with Normal
Mode.
Calculate required settling time and set the post convert-start tracking time using the
AD0TK bits.
Choose the repeat count.
Choose the output word justification (Right-Justified or Left-Justified).
Enable or disable the End of Conversion and Window Comparator Interrupts.
Rev. 1.1
C8051F410/1/2/3
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 Timer 3 overflow (i.e., timed continuous conversions)
A rising edge on the CNVSTR input signal (pin P0.6)
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 or Timer 3 overflows are used as the conversion source, Low Byte overflows are used if Timer 2/3 is in 8-bit mode; High byte overflows are used if Timer 2/3 is in 16-bit mode. See
Section “24. Timers” on page 231 for timer configuration.
Important Note About Using CNVSTR: The CNVSTR input pin also functions as Port Pin P0.6. When the
CNVSTR input is used as the ADC0 conversion source, Port Pin P0.6 should be skipped by the Digital
Crossbar. To configure the Crossbar to skip P0.6, set bit 6 in the P0SKIP register to logic 1. See Section
“18. Port Input/Output” on page 147 for details on Port I/O configuration.
5.3.2. Tracking Modes
According to Table 5.3 and Table 5.4, 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.
Rev. 1.1
53
C8051F410/1/2/3
Depending on the output connected to the ADC input, additional tracking time, more than is specified in
Table 5.3 and Table 5.4, may be required after changing MUX settings. See the settling time requirements
described in Section “5.3.6. Settling Time Requirements” on page 58.
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 5.3 and Table 5.4. 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 5.3
and Table 5.4.
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.
54
Rev. 1.1
C8051F410/1/2/3
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
...
S2
Track
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. 1.1
55
C8051F410/1/2/3
5.3.4. Burst Mode
Burst Mode is a power saving feature that allows ADC0 to remain in a low power state between conversions. When Burst Mode is enabled, ADC0 wakes from a low power state, accumulates 1, 4, 8, or 16 samples using an internal Burst Mode clock (approximately 25 MHz), then re-enters a low power state. Since
the Burst Mode clock is independent of the system clock, ADC0 can perform multiple conversions then
enter a 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 yste m C lo ck
C o n ve rt S ta rt
P o st-T ra ckin g
AD 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 ckin g
AD 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 ck
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 ck
T
C ..
AD 0PW R
P o st-T ra ckin g
AD 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 ckin g
AD 0TM = 11
AD0EN = 1
T ra ck
T
C
T
C
T
C
T
C
T ra ck
T
C
T
C
T
C ..
T = T ra ckin g
C = C o n ve rtin g
Figure 5.5. 12-Bit ADC Burst Mode Example with Repeat Count Set to 4
56
Rev. 1.1
C8051F410/1/2/3
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 in Table 5.1 for
both right-justified and left-justified data.
Table 5.1. ADC0 Examples of Right- and Left-Justified Samples
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. Sets
of 4, 8, or 16 consecutive samples can be accumulated and represented in unsigned integer format. The
repeat count can be selected using the AD0RPT bits in the ADC0CF register. The value must be rightjustified (AD0LJST = “0”), and unused bits in the ADC0H and ADC0L registers are set to '0'. The example
in Table 5.2 shows the right-justified result for various input voltages and repeat counts. 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.
Table 5.2. ADC0 Repeat Count Examples at Various Input Voltages
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. 1.1
Repeat Count = 16
0xFFF0
0x8000
0x7FF0
0x0000
57
C8051F410/1/2/3
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 VDD with respect to GND, RTOTAL
reduces to RMUX. See Table 5.3 and Table 5.4 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 = 5 kΩ
CSAMPLE = 12 pF
RCInput= RMUX * CSAMPLE
Figure 5.6. ADC0 Equivalent Input Circuits
58
Rev. 1.1
C8051F410/1/2/3
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
10000
10001
10010
10011
10100
10101
10110
10111
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
P2.0
P2.1
P2.2
P2.3*
P2.4*
P2.5*
P2.6*
P2.7
Temp Sensor
VDD
GND
*Note: Only applies to C8051F410/2; selection RESERVED on C8051F411/3 devices.
Rev. 1.1
59
C8051F410/1/2/3
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
Reserved
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 5.3.
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
FCLK
CLK SAR = ---------------------------AD0SC + 1
or
*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.
Note:
Bit0:
60
The ADC0 output register is automatically reset to 0x0000 upon reaching the last conversion
specified by the repeat counter. If the ADC is disabled during a conversion and re-enabled later,
the ADC0H and ADC0L registers should be manually cleared to 0x00.
RESERVED. Read = 0b; Must write 0b.
Rev. 1.1
C8051F410/1/2/3
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 accumulated result. Bits 7–4 are 0000b.
01: Bits 5–0 are the upper 6 bits of the accumulated result. Bits 7–6 are 00b.
10: Bits 6–0 are the upper 7 bits of the accumulated result. Bit 7 is 0b.
11: Bits 7–0 are the upper 8 bits of the accumulated 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. 1.1
61
C8051F410/1/2/3
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:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bits1-0:
62
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.
BURSTEN: ADC0 Burst Mode Enable Bit.
0: ADC0 Burst Mode Disabled.
1: ADC0 Burst Mode Enabled.
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.
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
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.
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).
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 3.
10: ADC0 conversion initiated on rising edge of external CNVSTR.
11: ADC0 conversion initiated on overflow of Timer 2.
Rev. 1.1
C8051F410/1/2/3
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 low power state.
For BURSTEN = 1 and AD0EN = 0:
ADC0 enters the low power state as specified in Table 5.3 and Table 5.4 and is enabled
after each convert start signal. The Power Up time is programmed according to the following
equation:
Tstartup
AD0PWR = ---------------------- – 1
400ns
or
Tstartup = ( AD0PWR + 1 )400ns
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. 1.1
63
C8051F410/1/2/3
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.
64
Rev. 1.1
C8051F410/1/2/3
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. 1.1
65
C8051F410/1/2/3
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)
VREF x (4095/
4096)
0x0FFF
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
66
Rev. 1.1
C8051F410/1/2/3
Table 5.3. ADC0 Electrical Characteristics (VDD = 2.5 V, VREF = 2.2 V)
VDD = 2.5 V, VREF = 2.2 V (REFSL=0), –40 to +85 °C unless otherwise specified. Typical values are given
at 25 ºC.
Parameter
Conditions
Min
Typ
Max
Units
DC Accuracy
Resolution
12
Integral Nonlinearity
Differential Nonlinearity
—
Guaranteed Monotonic
—
bits
±1
LSB
—
—
±1
LSB
Offset Error
—
±3
±10
LSB
Full Scale Error
—
±3
±10
LSB
Dynamic Performance (10 kHz sine-wave Single-ended input, 0 to 1 dB below Full Scale, 200 ksps)
Signal-to-Noise Plus Distortion
Regular Mode (BURSTEN = '0')
Burst Mode (BURSTEN = '0')
66
60
69
63
—
—
dB
Total Harmonic Distortion
Up to the 5th harmonic
—
–77
—
dB
—
–94
—
dB
—
—
3
MHz
Conversion Time in SAR Clocks1
—
13
—
clocks
Track/Hold Acquisition Time2
1
—
—
µs
Throughput Rate
—
—
200
ksps
Input Voltage Range
0
—
VREF
V
Input Capacitance
—
12
—
pF
Linearity3,4
—
±0.2
—
°C
Slope4
—
2.95
—
mV/°C
Slope Error3
—
±73
—
µV/°C
—
900
—
mV
—
±17
—
mV
—
680
1000
µA
Burst Mode (Idle)
—
100
—
µA
Power Supply Rejection
—
1
—
mV/V
Spurious-Free Dynamic Range
Conversion Rate
SAR Conversion Clock
Regular Mode (BURSTEN = '0')
Analog Inputs
Temperature Sensor
Offset4
Offset
(Temp = 0 °C)
Error3
Power Specifications
Power Supply Current
(VDD supplied to ADC0)
Operating Mode, 200 ksps
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 58.
3. Represents one standard deviation from the mean.
4. Includes ADC offset, gain, and linearity variations.
Rev. 1.1
67
C8051F410/1/2/3
Table 5.4. ADC0 Electrical Characteristics (VDD = 2.1 V, VREF = 1.5 V)
VDD = 2.1 V, VREF = 1.5 V (REFSL = 0), –40 to +85 °C unless otherwise specified. Typical values are given at
25 ºC.
Parameter
Conditions
Min
Typ
Max
Units
DC Accuracy
Resolution
12
Integral Nonlinearity
Differential Nonlinearity
—
Guaranteed Monotonic
—
bits
±1
LSB
—
—
±1
LSB
Offset Error
—
±3
±10
LSB
Full Scale Error
—
±3
±10
LSB
Dynamic Performance (10 kHz sine-wave Single-ended input, 0 to 1 dB below Full Scale, 200 ksps)
Signal-to-Noise Plus Distortion
Regular Mode (BURSTEN = '0')
Burst Mode (BURSTEN = '0')
66
60
68
62
—
—
dB
Total Harmonic Distortion
Up to the 5th harmonic
—
–75
—
dB
—
–90
—
dB
—
—
3
MHz
Conversion Time in SAR Clocks1
—
13
—
clocks
Track/Hold Acquisition Time2
1
—
—
µs
Throughput Rate
—
—
200
ksps
Input Voltage Range
0
—
VREF
V
Input Capacitance
—
12
—
pF
Linearity3,4
—
±0.2
—
°C
Slope4
—
2.95
—
mV/°C
Slope Error3
—
±73
—
µV/°C
—
900
—
mV
—
±17
—
mV
Power Supply Current (VDD supOperating Mode, 200 ksps
plied to ADC0)
—
650
1000
µA
Burst Mode (Idle)
—
100
—
µA
Power Supply Rejection
—
1
—
mV/V
Spurious-Free Dynamic Range
Conversion Rate
SAR Conversion Clock
Regular Mode (BURSTEN = '0')
Analog Inputs
Temperature Sensor
Offset
(Temp = 0 °C)
Offset Error3
Power Specifications
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 58.
3. Represents one standard deviation from the mean.
4. Includes ADC offset, gain, and linearity variations.
68
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6.
12-Bit Current Mode DACs (IDA0 and IDA1)
CNVSTR
Timer 3
Timer 2
Timer 1
Timer 0
IDAnH
IDAnEN
IDAnCM2
IDAnCM1
IDAnCM0
IDAnRJST
IDAnOMD1
IDAnOMD0
8
IDAnL
Latch
IDAnH
IDAnCN
The C8051F41x devices include two 12-bit current-mode Digital-to-Analog Converters (IDACs). The maximum current output of the IDACs can be adjusted for four different current settings; 0.25 mA, 0.5 mA,
1 mA, and 2 mA. The IDACs can be individually enabled or disabled using the enable bits in the corresponding IDAC Control Register (IDA0CN or IDA1CN). When both IDACs are enabled, their outputs may
be routed to individual pins or merged onto a single pin. An internal bandgap bias generator is used to generate a reference current for the IDACs whenever they are enabled. IDAC updates can be performed ondemand, scheduled on a Timer overflow, or synchronized with an external pin edge. Figure 6.1 shows a
block diagram of the IDAC circuitry.
12
IDAn
IDAn
Output
4
Figure 6.1. IDAC Functional Block Diagram
6.1.
IDAC Output Scheduling
A flexible output update mechanism allows for seamless full-scale changes and supports jitter-free
updates for waveform generation. Three update modes are provided, allowing IDAC output updates on a
write to the IDAC’s data register, on a Timer overflow, or on an external pin edge.
6.1.1. Update Output On-Demand
In its default mode (IDAnCN.[6:4] = ‘111’) the IDAC output is updated “on-demand” with a write to the data
register high byte (IDAnH). It is important to note that in this mode, writes to the data register low byte
(IDAnL) are held and have no effect on the IDAn output until a write to IDAnH takes place. Since data from
both the high and low bytes of the data register are immediately latched to IDAn after a write to IDAnH, the
write sequence when writing a full 12-bit word to the IDAC data registers should be IDAnL followed
by IDAnH. When the data word is left justified, the IDAC can be used in 8-bit mode by initializing IDAnL to
the desired value (typically 0x00), and writing data only to IDA0H.
Rev. 1.1
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C8051F410/1/2/3
6.1.2. Update Output Based on Timer Overflow
The IDAC output update can be scheduled on a Timer overflow. This feature is useful in systems where the
IDAC is used to generate a waveform of a defined sampling rate, by eliminating the effects of variable
interrupt latency and instruction execution on the timing of the IDAC output. When the IDAnCM bits
(IDAnCN.[6:4]) are set to ‘000’, ‘001’, ‘010’ or ‘011’, writes to both IDAC data registers (IDAnL and IDAnH)
are held until an associated Timer overflow event (Timer 0, Timer 1, Timer 2 or Timer 3, respectively)
occurs, at which time the IDAnH:IDAnL contents are copied to the IDAC input latch, allowing the IDAC output to change to the new value. When updates are scheduled based on Timer 2 or 3, updates occur on
low-byte overflows if Timer 2 or 3 is in 8-bit mode and high-byte overflows if Timer 2 or 3 is in 16-bit mode.
6.1.3. Update Output Based on CNVSTR Edge
The IDAC output can also be configured to update on a rising edge, falling edge, or both edges of the
external CNVSTR signal. When the IDAnCM bits (IDAnCN.[6:4]) are set to ‘100’, ‘101’, or ‘110’, writes to
the IDAC data registers (IDAnL and IDAnH) are held until an edge occurs on the CNVSTR input pin. The
particular setting of the IDAnCM bits determines whether the IDAC output is updated on rising, falling, or
both edges of CNVSTR. When a corresponding edge occurs, the IDAnH:IDAnL contents are copied to the
IDAC input latch, allowing the IDAC output to change to the new value.
6.2.
IDAC Output Mapping
The IDAC data word can be Left Justified or Right Justified as shown in Figure 6.2. When Left Justified, the
8 MSBs of the data word (D11-D4) are mapped to bits 7-0 of the IDAnH register and the 4 LSBs of the data
word (D3-D0) are mapped to bits 7-4 of the IDAnL register. When Right Justified, the 4 MSBs of the data
word (D11-D8) are mapped to bits 3-0 of the IDAnH register and the 8 LSBs of the data word (D7-D0) are
mapped to bits 7-0 of the IDAnL register. The IDAC data word justification is selected using the IDAnRJST
bit (IDAnCN.2).
The full-scale output current of the IDAC is selected using the IDAnOMD bits (IDAnCN[1:0]). By default,
the IDAC is set to a full-scale output current of 2 mA. The IDAnOMD bits can also be configured to provide
full-scale output currents of 0.25 mA, 0.5 mA, or 1 mA.
Left Justified Data (IDAnRJST = 0):
IDAnH
D11
D10
D9
D8
D7
D6
IDAnL
D5
D4
D3
D2
D1
D0
D9
D8
D7
D6
D5
D4
Right Justified Data (IDAnRJST = 1):
IDAnH
D11
D10
IDAnL
D3
D2
D1
D0
IDAn Data Word
Output Current vs IDAnOMD bit setting
(D11–D0)
‘11’ (2 mA)
‘10’ (1 mA)
‘01’ (0.5 mA)
‘00’ (0.25 mA)
0x000
0 mA
0 mA
0 mA
0 mA
0x001
1/4096 x 2 mA
1/4096 x 1 mA
1/4096 x 0.5 mA
1/4096 x 0.25 mA
0x800
2048/4096 x 2 mA 2048/4096 x 1 mA 2048/4096 x 0.5 mA 2048/4096 x 0.25 mA
0xFFF
4095/4096 x 2 mA 4095/4096 x 1 mA 4095/4096 x 0.5 mA 4095/4096 x 0.25 mA
Figure 6.2. IDAC Data Word Mapping
70
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C8051F410/1/2/3
SFR Definition 6.1. IDA0CN: IDA0 Control
R/W
R/W
IDA0EN
Bit7
R/W
R/W
R/W
R
-
IDA0RJST
Bit4
Bit3
Bit2
IDA0CM
Bit6
Bit5
R/W
R/W
IDA0OMD
Bit1
Reset Value
01110011
Bit0
SFR Address: 0xB9
Bit 7:
IDA0EN: IDA0 Enable Bit.
0: IDA0 Disabled.
1: IDA0 Enabled.
Bits 6–4: IDA0CM[2:0]: IDA0 Update Source Select Bits.
000: DAC output updates on Timer 0 overflow.
001: DAC output updates on Timer 1 overflow.
010: DAC output updates on Timer 2 overflow.
011: DAC output updates on Timer 3 overflow.
100: DAC output updates on rising edge of CNVSTR.
101: DAC output updates on falling edge of CNVSTR.
110: DAC output updates on any edge of CNVSTR.
111: DAC output updates on write to IDA0H.
Bit 3:
Reserved. Read = 0b, Write = 0b.
Bit 2:
IDA0RJST: IDA0 Right Justify Select Bit.
0: IDA0 data in IDA0H:IDA0L is left justified.
1: IDA0 data in IDA0H:IDA0L is right justified.
Bits 1:0: IDA0OMD[1:0]: IDA0 Output Mode Select Bits.
00: 0.25 mA full-scale output current.
01: 0.5 mA full-scale output current.
10: 1.0 mA full-scale output current.
11: 2.0 mA full-scale output current.
SFR Definition 6.2. IDA0H: IDA0 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: 0x97
Bits 7–0: IDA0 Data Word High-Order Bits.
For IDA0RJST = 0:
Bits 7-0 hold the most significant 8-bits of the 12-bit IDA0 Data Word.
For IDA0RJST = 1:
Bits 3-0 hold the most significant 4-bits of the 12-bit IDA0 Data Word. Bits 7-4 are 0000b.
Rev. 1.1
71
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SFR Definition 6.3. IDA0L: IDA0 Data 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: 0x96
Bits 7–0: IDA0 Data Word Low-Order Bits.
For IDA0RJST = 0:
Bits 7-4 hold the least significant 4-bits of the 12-bit IDA0 Data Word. Bits 3–0 are 0000b.
For IDA0RJST = 1:
Bits 7–0 hold the least significant 8-bits of the 12-bit IDA0 Data Word.
SFR Definition 6.4. IDA1CN: IDA1 Control
R/W
R/W
IDA1EN
Bit7
R/W
R/W
R/W
R
-
IDA1RJST
Bit4
Bit3
Bit2
IDA1CM
Bit6
Bit5
R/W
R/W
IDA1OMD
Bit1
Reset Value
01110011
Bit0
SFR Address: 0xB5
Bit 7:
IDA1EN: IDA0 Enable Bit.
0: IDA1 Disabled.
1: IDA1 Enabled.
Bits 6–4: IDA1CM[2:0]: IDA1 Update Source Select Bits.
000: DAC output updates on Timer 0 overflow.
001: DAC output updates on Timer 1 overflow.
010: DAC output updates on Timer 2 overflow.
011: DAC output updates on Timer 3 overflow.
100: DAC output updates on rising edge of CNVSTR.
101: DAC output updates on falling edge of CNVSTR.
110: DAC output updates on any edge of CNVSTR.
111: DAC output updates on write to IDA1H.
Bit 3:
Reserved. Read = 0b, Write = 0b.
Bit 2:
IDA1RJST: IDA1 Right Justify Select Bit.
0: IDA1 data in IDA1H:IDA1L is left justified.
1: IDA1 data in IDA1H:IDA1L is right justified.
Bits 1–0: IDA1OMD[1:0]: IDA1 Output Mode Select Bits.
00: 0.25 mA full-scale output current.
01: 0.5 mA full-scale output current.
10: 1.0 mA full-scale output current.
11: 2.0 mA full-scale output current.
72
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SFR Definition 6.5. IDA1H: IDA0 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: 0xF5
Bits 7–0: IDA1 Data Word High-Order Bits.
For IDA0RJST = 0:
Bits 7-0 hold the most significant 8-bits of the 12-bit IDA1 Data Word.
For IDA0RJST = 1:
Bits 3-0 hold the most significant 4-bits of the 12-bit IDA1 Data Word. Bits 7–4 are 0000b.
SFR Definition 6.6. IDA1L: IDA1 Data 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: 0xF4
Bits 7–0: IDA1 Data Word Low-Order Bits.
For IDA0RJST = 0:
Bits 7-4 hold the least significant 4-bits of the 12-bit IDA1 Data Word. Bits 3–0 are 0000b.
For IDA0RJST = 1:
Bits 7–0 hold the least significant 8-bits of the 12-bit IDA1 Data Word.
6.3.
IDAC External Pin Connections
The IDA0 output is connected to P0.0, and the IDA1 output can be connected to P0.0 or P0.1. The output
pin for IDA1 is selected using IDAMRG (REF0CN.7). When the enable bits for both IDACs (IDAnEN) are
set to ‘0’, the IDAC outputs behave as a normal GPIO pins. When either IDAC’s enable bit is set to ‘1’, the
digital output drivers and weak pullup for the selected IDAC pin are automatically disabled, and the pin is
connected to the IDAC output. When using the IDACs, the selected IDAC pin(s) should be skipped in the
Crossbar by setting the corresponding PnSKIP bits to a ‘1’. Figure 6.3 shows the pin connections for IDA0
and IDA1.
When both IDACs are enabled and IDAMRG is set to logic 1, the output of both IDACs is merged onto
P0.0.
Rev. 1.1
73
C8051F410/1/2/3
IDA0EN
IDA0
0
P0.0
1
IDA1EN
IDA1
0
1
1
0
IDAMRG
Figure 6.3. IDAC Pin Connections
74
Rev. 1.1
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C8051F410/1/2/3
Table 6.1. IDAC Electrical Characteristics
–40 to +85 °C, VDD = 2.0 V Full-scale output current set to 2 mA unless otherwise specified. Typical values are given
at 25 ºC.
Parameter
Conditions
Min
Typ
Max
Units
Static Performance
Resolution
12
Integral Nonlinearity
bits
—
—
±10
LSB
Differential Nonlinearity
Guaranteed Monotonic
—
—
±1
LSB
Output Compliance Range
Guaranteed by Design, Applies to
entire VDD range
—
—
VDD – 1.2
V
—
0
—
LSB
—
0.05
2
%
Gain-Error Tempco
—
320
—
nA/°C
VDD Power Supply Rejection
Ratio
—
2
—
µA/V
Output Capacitance
—
2
—
pF
—
10
—
µs
—
0.5
0.5
0.5
—
%
%
%
—
2.1
1.1
0.6
0.35
—
mA
mA
mA
mA
Offset Error
Gain Error
2 mA Full Scale Output Current
Dynamic Performance
Startup Time
Gain Variation From 2 mA
range
1 mA Full Scale Output Current
0.5 mA Full Scale Output Current
0.25 mA Full Scale Output Current
Power Consumption
Power Supply Current
2 mA Full Scale Output Current
1 mA Full Scale Output Current
0.5 mA Full Scale Output Current
0.25 mA Full Scale Output Current
Rev. 1.1
75
C8051F410/1/2/3
NOTES:
76
Rev. 1.1
C8051F410/1/2/3
7.
Voltage Reference
The Voltage reference MUX on C8051F41x devices is configurable to use an externally connected voltage
reference, the internal reference voltage generator, or the VDD power supply voltage (see Figure 7.1). The
REFSL bit in the Reference Control register (REF0CN) selects the reference source. For an external
source or the internal reference, REFSL should be set to ‘0’. To use VDD as the reference source, REFSL
should be set to ‘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 selected between 1.5 V and 2.2 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 7.1). 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’.
The BIASE bit enables the internal voltage bias generator, which is used by the ADC, Temperature Sensor,
internal oscillators, and IDACs. 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 7.1 for REF0CN register details.
REFLV
The electrical specifications for the voltage reference circuit are given in Table 7.1.
REFLV
Figure 7.1. Voltage Reference Functional Block Diagram
Rev. 1.1
77
C8051F410/1/2/3
Important Note About the VREF Pin: Port pin P1.2 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, P1.2
should be configured as an analog pin, and skipped by the Digital Crossbar. To configure P1.2 as an analog pin, clear Bit 2 in register P1MDIN to ‘0’ and set Bit 2 in register P1 to '1'. To configure the Crossbar to
skip P1.2, set Bit 2 in register P1SKIP to ‘1’. Refer to Section “18. Port Input/Output” on page 147 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 7.1. REF0CN: Reference Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
IDAMRG
GF
ZTCEN
REFLV
REFSL
TEMPE
BIASE
REFBE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
0xD1
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
78
IDAMRG: IDAC Output Merge Select.
0: IDA1 Output is P0.1.
1: IDA1 Output is P0.0 (Merged with IDA0 Output).
GF. General Purpose Flag.
This bit is a general purpose flag for use under software control.
ZTCEN: Zero-TempCo Bias Enable Bit.
0: ZeroTC Bias Generator automatically enabled when needed.
1: ZeroTC Bias Generator forced on.
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 2.2 V.
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.
TEMPE: Temperature Sensor Enable Bit.
0: Internal Temperature Sensor off.
1: Internal Temperature Sensor on.
BIASE: Internal Analog Bias Generator Enable Bit.
0: Internal Analog Bias Generator automatically enabled when needed.
1: Internal Analog Bias Generator on.
REFBE: Internal Reference Buffer Enable Bit.
0: Internal Reference Buffer disabled.
1: Internal Reference Buffer enabled. Internal voltage reference driven on the VREF pin.
Rev. 1.1
C8051F410/1/2/3
Table 7.1. Voltage Reference Electrical Characteristics
VDD = 2.0 V; –40 to +85 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
25 °C ambient (REFLV = 0)
25 °C ambient (REFLV = 1), VDD = 2.5 V
1.47
2.16
1.5
2.2
1.53
2.24
V
VREF Short-Circuit Current
—
3.0
—
mA
VREF Temperature Coefficient
—
35
—
ppm/°C
—
10
—
ppm/µA
—
—
2.5
55
—
—
ms
µs
—
—
6.8
144
—
—
ms
µs
—
2
—
mV/V
0
—
VDD
V
Sample Rate = 200 ksps; VREF = 2 V
—
5
—
µA
BIASE = ‘1’
—
22
—
µA
—
50
—
µA
Internal Reference (REFBE = 1)
Output Voltage
Load Regulation
Load = 0 to 200 µA to GND
VREF Turn-on Time
VDD = 2.5 V, VREF = 1.5 V:
4.7 µF tantalum, 0.1 µF ceramic bypass
0.1 µF ceramic bypass
VDD = 2.5 V, VREF = 2.2 V:
4.7 µF tantalum, 0.1 µF ceramic bypass
0.1 µF ceramic bypass
Power Supply Rejection
External Reference (REFBE = 0)
Input Voltage Range
Input Current
Bias Generators
ADC Bias Generator
Power Consumption (Internal)
Rev. 1.1
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NOTES:
80
Rev. 1.1
C8051F410/1/2/3
8.
Voltage Regulator (REG0)
C8051F41x 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 2.5 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 protected 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. A settling time associated with the voltage regulator is shown in
Table 8.1.
REG0
VREGIN
4.7 µF
.1 µF
VDD
VDD
4.7 µF
.1 µF
Figure 8.1. External Capacitors for Voltage Regulator Input/Output
If the internal voltage regulator is not used, the VREGIN input should be tied to VDD, as shown in Figure 8.2.
VREGIN
VDD
VDD
4.7 µF
.1 µF
Figure 8.2. External Capacitors for Voltage Regulator Input/Output
Rev. 1.1
81
C8051F410/1/2/3
SFR Definition 8.1. REG0CN: Regulator Control
R/W
R/W
REGDIS Reserved
Bit7
Bit6
R
R/W
R
R
R
—
REG0MD
—
—
—
Bit5
Bit4
Bit3
Bit2
Bit1
R
Reset Value
DROPOUT 00010000
Bit0
SFR Address: 0xC9
Bit 7:
REGDIS: Voltage Regulator Disable Bit.
This bit disables/enables the Voltage Regulator.
0: Voltage Regulator Enabled.
1: Voltage Regulator Disabled.
Bit 6:
RESERVED. Read = 0b. Must write 0b.
Bit 5:
UNUSED. Read = 0b. Write = don’t care.
Bit 4:
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 2.5 V (default).
Bits 3–1: UNUSED. Read = 0b. Write = don’t care.
Bit 0:
DROPOUT: Voltage Regulator Dropout Indicator Bit.
0: Voltage Regulator is not in dropout.
1: Voltage Regulator is in or near dropout.
Table 8.1. Voltage Regulator Electrical Specifications
VDD = 2.1 or 2.5 V; –40 to +85 °C unless otherwise specified. Typical values are given at 25 ºC.
Parameter
Conditions
Min
Typ
Max
Units
(See Note)
—
5.25
V
Load Current
—
—
50
mA
Load Regulation
—
7
15
mV/mA
2.0
2.35
2.1
2.5
2.25
2.55
V
—
—
1
1
1.5
1.5
µA
Dropout Indicator Detection
Threshold
—
65
—
mV
Output Voltage Tempco
—
600
—
µV/ºC
—
250
—
µs
Input Voltage Range (VREGIN)*
Output Voltage (VDD)
Output Current = 1 mA
REG0MD = ‘0’
REG0MD = ‘1’
Bias Current
REG0MD = ‘0’
REG0MD = ‘1’
VREG Settling Time
50 mA load with VREGIN = 2.5 V
and VDD load capacitor of 4.8 µF
*Note: Actual Output Voltage (VDD) = Nominal Output Voltage (VDD) – (Load Regulation x Load Current).
82
Rev. 1.1
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9.
Comparators
C8051F41x devices include two on-chip programmable voltage comparators: Comparator0 is shown in
Figure 9.1; Comparator1 is shown in Figure 9.2. The two comparators operate identically, but only Comparator0 can be used as a reset source.
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, CP1), or an
asynchronous “raw” output (CP0A, CP1A). 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 “18.2. Port I/O Initialization” on page 151). Comparator0 may also
be used as a reset source (see Section “15.5. Comparator0 Reset” on page 130).
The Comparator0 inputs are selected in the CPT0MX register (SFR Definition 9.2). The CMX0P3-CMX0P0
bits select the Comparator0 positive input; the CMX0N3-CMX0N0 bits select the Comparator0 negative
input. The Comparator1 inputs are selected in the CPT1MX register (SFR Definition 9.4). The CMX1P3CMX1P0 bits select the Comparator1 positive input; the CMX1N3-CMX1N0 bits select the Comparator1
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 (with a ‘1’ written to the corresponding Port Latch register), and configured to be skipped by the Crossbar (for details on Port configuration,
see Section “18.3. General Purpose Port I/O” on page 154)
CPT0CN
CP0EN
CP0OUT
CPT0MX
CMX0N3
CMX0N2
CMX0N1
CMX0N0
CMX0P3
CMX0P2
CP0RIF
CP0FIF
CP0HYP1
VDD
CP0
Interrupt
CP0HYP0
CP0HYN1
CP0HYN0
CMX0P1
CMX0P0
CP0
Rising-edge
P0.0
CP0
Falling-edge
P0.2
P0.1
P0.4
CP0 +
Interrupt
Logic
P0.3
P0.6
P0.5
CP0
+
P1.0
P0.7
D
P1.2
-
SET
CLR
D
Q
Q
SET
CLR
Q
Q
P1.1
Crossbar
P1.4
(SYNCHRONIZER)
P1.3
GND
P1.6
CP0A
P1.5
Reset
Decision
Tree
P2.0
P1.7
P2.2
P2.1
P2.4
CPT0MD
P2.3
CP0FIE
CP0 -
CP0RIE
P2.7
CP0MD1
P2.5
CP0MD0
P2.6
Figure 9.1. Comparator0 Functional Block Diagram
Rev. 1.1
83
C8051F410/1/2/3
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 “18.1. Priority Crossbar Decoder” on page 149 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 9.1.
CPT1CN
CPT1MX
The Comparator response time may be configured in software via the CPTnMD registers (see SFR Definition 9.3 and SFR Definition 9.5). Selecting a longer response time reduces the Comparator supply current.
See Table 9.1 for complete timing and current consumption specifications.
CMX1N3
CMX1N2
CMX1N1
CMX1N0
CMX1P3
CMX1P2
CMX1P1
CMX1P0
CP1EN
CP1OUT
CP1RIF
VDD
CP1FIF
CP1HYP1
CP1HYP0
CP1HYN1
CP1
Interrupt
CP1HYN0
CP1
Rising-edge
P0.0
CP1
Falling-edge
P0.2
P0.1
P0.4
CP1 +
Interrupt
Logic
P0.3
P0.6
P0.5
CP1
+
P1.0
P0.7
D
P1.2
-
SET
CLR
D
Q
Q
SET
CLR
Q
Q
P1.1
Crossbar
P1.4
(SYNCHRONIZER)
P1.3
GND
P1.6
CP1A
P1.5
P2.0
P1.7
P2.2
P2.1
P2.4
CPT1MD
P2.3
CP1 -
CP1FIE
P2.7
CP1RIE
P2.5
CP1MD1
CP1MD0
P2.6
Figure 9.2. Comparator1 Functional Block Diagram
84
Rev. 1.1
C8051F410/1/2/3
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 9.3. Comparator Hysteresis Plot
The Comparator hysteresis is software-programmable via its Comparator Control register CPTnCN (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 CPTnCN
(shown in SFR Definition 9.1 and SFR Definition 9.6). The amount of negative hysteresis voltage is
determined by the settings of the CPnHYN bits. As shown in Table 9.1, settings of 20, 10 or 5 mV of
negative hysteresis can be programmed, or negative hysteresis can be disabled. In a similar way, the
amount of positive hysteresis is determined by setting the CPnHYP bits.
Comparator interrupts can be generated on both rising-edge and falling-edge output transitions. (For Interrupt enable and priority control, see Section “12. Interrupt Handler” on page 110). The CPnFIF 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 CPnEN 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 CPnOUT bit. The Comparator is enabled by setting the CPnEN 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 9.1 on page 92.
Rev. 1.1
85
C8051F410/1/2/3
SFR Definition 9.1. 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.
86
Rev. 1.1
C8051F410/1/2/3
SFR Definition 9.2. CPT0MX: Comparator0 MUX Selection
R/W
R/W
R/W
R/W
R/W
CMX0N3 CMX0N2 CMX0N1 CMX0N0 CMX0P3
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
CMX0P2
CMX0P1
CMX0P0
11111111
Bit2
Bit1
Bit0
SFR Address:
Bit3
Reset Value
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
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
x
x
Negative Input
P0.1
P0.3
P0.5
P0.7
P1.1
P1.3
P1.5
P1.7
P2.1
P2.3*
P2.5*
P2.7
Reserved
*Note: Available only on the C8051F410/2.
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
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
x
x
Positive Input
P0.0
P0.2
P0.4
P0.6
P1.0
P1.2
P1.4
P1.6
P2.0
P2.2
P2.4*
P2.6*
Reserved
*Note: Available only on the C8051F410/2.
Rev. 1.1
87
C8051F410/1/2/3
SFR Definition 9.3. CPT0MD: Comparator0 Mode Selection
R/W
R/W
R/W
R/W
R/W
R/W
RESERVED
-
CP0RIE
CP0FIE
-
-
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
R/W
R/W
Reset Value
CP0MD1 CP0MD0 00000010
Bit1
Bit0
SFR Address:
0x9D
Bit7:
Bit6:
Bit5:
RESERVED. Read = 0b. Must Write 0b.
UNUSED. Read = 0b. Write = don’t care.
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.
Bits3–2: UNUSED. Read = 00b. Write = don’t care.
Bits1–0: CP0MD1–CP0MD0: Comparator0 Mode Select
These bits affect the response time and power consumption for Comparator0.
Mode
0
1
2
3
88
CP0MD1
0
0
1
1
CP0MD0
0
1
0
1
Effect
Fastest Response Time
—
—
Lowest Power Consumption
Rev. 1.1
C8051F410/1/2/3
SFR Definition 9.4. CPT1MX: Comparator1 MUX Selection
R/W
R/W
R/W
R/W
R/W
CMX1N3 CMX1N2 CMX1N1 CMX1N0 CMX1P3
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
CMX1P2
CMX1P1
CMX1P0
11111111
Bit2
Bit1
Bit0
SFR Address:
Bit3
Reset Value
0x9E
Bits7–4: CMX1N3–CMX1N0: Comparator1 Negative Input MUX Select.
These bits select which Port pin is used as the Comparator1 negative input.
CMX1N3 CMX1N2 CMX1N1 CMX1N0
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
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
x
x
Negative Input
P0.1
P0.3
P0.5
P0.7
P1.1
P1.3
P1.5
P1.7
P2.1
P2.3*
P2.5*
P2.7
Reserved
*Note: Available only on the C8051F410/2.
Bits3–0: CMX1P3–CMX1P0: Comparator1 Positive Input MUX Select.
These bits select which Port pin is used as the Comparator1 positive input.
CMX1P3 CMX1P2 CMX1P1 CMX1P0
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
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
x
x
Positive Input
P0.0
P0.2
P0.4
P0.6
P1.0
P1.2
P1.4
P1.6
P2.0
P2.2
P2.4*
P2.6*
Reserved
*Note: Available only on the C8051F410/2.
Rev. 1.1
89
C8051F410/1/2/3
SFR Definition 9.5. CPT1MD: Comparator1 Mode Selection
R/W
R/W
R/W
R/W
R/W
R/W
RESERVED
-
CP1RIE
CP1FIE
-
-
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
R/W
R/W
Reset Value
CP1MD1 CP1MD0 00000010
Bit1
Bit0
SFR Address:
0x9C
Bit7:
Bit6:
Bit5:
RESERVED. Read = 0b. Must Write 0b.
UNUSED. Read = 0b. Write = don’t care.
CP1RIE: Comparator Rising-Edge Interrupt Enable.
0: Comparator rising-edge interrupt disabled.
1: Comparator rising-edge interrupt enabled.
Bit4:
CP1FIE: Comparator Falling-Edge Interrupt Enable.
0: Comparator falling-edge interrupt disabled.
1: Comparator falling-edge interrupt enabled.
Bits3–2: UNUSED. Read = 00b. Write = don’t care.
Bits1–0: CP1MD1–CP1MD0: Comparator1 Mode Select.
These bits affect the response time and power consumption for Comparator1.
Mode
0
1
2
3
90
CP1MD1
0
0
1
1
CP1MD0
0
1
0
1
Effect
Fastest Response Time
—
—
Lowest Power Consumption
Rev. 1.1
C8051F410/1/2/3
SFR Definition 9.6. CPT1CN: Comparator1 Control
R/W
R
R/W
R/W
CP1EN
CP1OUT
CP1RIF
CP1FIF
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
R/W
Reset Value
CP1HYP1 CP1HYP0 CP1HYN1 CP1HYN0 00000000
Bit3
Bit2
Bit1
Bit0
SFR Address:
0x9A
Bit7:
CP1EN: Comparator1 Enable Bit.
0: Comparator1 Disabled.
1: Comparator1 Enabled.
Bit6:
CP1OUT: Comparator1 Output State Flag.
0: Voltage on CP1+ < CP1-.
1: Voltage on CP1+ > CP1-.
Bit5:
CP1RIF: Comparator1 Rising-Edge Flag.
0: No Comparator1 Rising Edge has occurred since this flag was last cleared.
1: Comparator1 Rising Edge has occurred.
Bit4:
CP1FIF: Comparator1 Falling-Edge Flag.
0: No Comparator1 Falling-Edge has occurred since this flag was last cleared.
1: Comparator1 Falling-Edge has occurred.
Bits3–2: CP1HYP1–0: Comparator1 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: CP1HYN1–0: Comparator1 Negative Hysteresis Control Bits.
00: Negative Hysteresis Disabled.
01: Negative Hysteresis = 5 mV.
10: Negative Hysteresis = 10 mV.
11: Negative Hysteresis = 20 mV.
Rev. 1.1
91
C8051F410/1/2/3
Table 9.1. Comparator Electrical Characteristics
VDD = 2.0 V, –40 to +85 °C unless otherwise noted. All specifications apply to both Comparator0 and Comparator1
unless otherwise noted. Typical values are given at 25 ºC.
Parameter
Response Time:
Mode 0, Vcm1 = 1.5 V
Response Time:
Mode 1, Vcm1 = 1.5 V
Response Time:
Mode 2, Vcm1 = 1.5 V
Response Time:
Mode 3, Vcm1 = 1.5 V
Conditions
Min
Typ
Max
Units
CP0+ – CP0– = 100 mV
—
120
—
ns
CP0+ – CP0– = –100 mV
—
160
—
ns
CP0+ – CP0– = 100 mV
—
200
—
ns
CP0+ – CP0– = –100 mV
—
340
—
ns
CP0+ – CP0– = 100 mV
—
360
—
ns
CP0+ – CP0– = –100 mV
—
720
—
ns
CP0+ – CP0– = 100 mV
—
2.2
—
µs
CP0+ – CP0– = –100 mV
—
7.2
—
µs
—
1.5
14
mV/V
Common-Mode Rejection Ratio2
Positive Hysteresis 1
CP0HYP1-0 = 00
—
0.5
2.0
mV
Positive Hysteresis 2
CP0HYP1-0 = 01
2
4.5
10
mV
Positive Hysteresis 3
CP0HYP1-0 = 10
5
9.0
20
mV
Positive Hysteresis 4
CP0HYP1-0 = 11
13
18.0
40
mV
Negative Hysteresis 1
CP0HYN1-0 = 00
—
–0.5
–2.0
mV
Negative Hysteresis 2
CP0HYN1-0 = 01
–2
–4.5
–10
mV
Negative Hysteresis 3
CP0HYN1-0 = 10
–5
–9.0
–20
mV
Negative Hysteresis 4
CP0HYN1-0 = 11
–13
–18.0
–40
mV
–0.25
—
VDD + 0.25
V
Input Capacitance
—
4
—
pF
Input Bias Current
—
0.5
—
nA
–10
—
10
mV
Power Supply Rejection2
—
0.2
4
mV/V
Power-up Time
—
2.3
—
µs
Mode 0
—
13
30
µA
Mode 1
—
6.0
20
µA
Mode 2
—
3.0
10
µA
Mode 3
—
1.0
5
µA
Inverting or Non-Inverting Input
Voltage Range
Input Offset Voltage
Power Supply
Supply Current at DC
Notes:
1. Vcm is the common-mode voltage on CP0+ and CP0–.
2. Guaranteed by design and/or characterization.
92
Rev. 1.1
C8051F410/1/2/3
10. 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 C8051F41x family has a superset of all the peripherals included with a standard 8051. See Section “1. System Overview” on page 19 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 10.1 for a block diagram).
The CIP-51 core includes the following features:
-
- Fully Compatible with MCS-51 Instruction
Set
- 50 MIPS Peak Throughput
- 256 Bytes of Internal RAM
Extended Interrupt Handler
Reset Input
Power Management Modes
Integrated Debug Logic
D8
D8
ACCUMULATOR
STACK POINTER
TMP1
TMP2
SRAM
ADDRESS
REGISTER
PSW
SRAM
(256 X 8)
D8
D8
D8
ALU
D8
DATA BUS
B REGISTER
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.
MEM_ADDRESS
D8
MEM_CONTROL
A16
MEMORY
INTERFACE
MEM_WRITE_DATA
MEM_READ_DATA
PIPELINE
RESET
D8
CONTROL
LOGIC
SYSTEM_IRQs
CLOCK
D8
STOP
IDLE
POWER CONTROL
REGISTER
INTERRUPT
INTERFACE
EMULATION_IRQ
D8
Figure 10.1. CIP-51 Block Diagram
Rev. 1.1
93
C8051F410/1/2/3
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 50 MHz, it has a peak throughput of 50 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.
10.1. 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.
10.1.1. 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 10.1 is the
CIP-51 Instruction Set Summary, which includes the mnemonic, number of bytes, and number of clock
cycles for each instruction.
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10.1.2. 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
“16. Flash Memory” on page 135 for further details.
Table 10.1. 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
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
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
2
2
3
1
2
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 (SFR
Definition 16.3. FLSCL: Flash Scale).
Rev. 1.1
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Table 10.1. CIP-51 Instruction Set Summary1 (Continued)
Mnemonic
ORL A, @Ri
ORL A, #data
ORL direct, A
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
1
2
2
3
1
2
1
2
2
3
1
1
1
1
1
1
1
Clock
Cycles
2
2
2
3
1
2
2
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 indirect RAM to A
OR immediate to A
OR A to direct byte
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
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
1
1
1
1
1
2
4 to 72
3
3
3
3
2
1
2
2
2
1
2
2
2
2
3
2
3
2
2
2
3
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 (SFR
Definition 16.3. FLSCL: Flash Scale).
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Table 10.1. CIP-51 Instruction Set Summary1 (Continued)
Mnemonic
POP direct
XCH A, Rn
XCH A, direct
XCH A, @Ri
XCHD A, @Ri
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
Bytes
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
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
2
1
2
1
1
Clock
Cycles
2
1
2
2
2
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
3
3
2
3
1
4
5
6
6
4
5
4
4
2/4
2/4
3/5
3/5
3/5
4/6
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 (SFR
Definition 16.3. FLSCL: Flash Scale).
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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 (0x000x7F) 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
2K-byte 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 8K-byte program memory space.
There is one unused opcode (0xA5) that performs the same function as NOP.
All mnemonics copyrighted © Intel Corporation 1980.
10.2. 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 10.1. 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.
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SFR Definition 10.2. 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 10.3. 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.
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SFR Definition 10.4. 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
Bit
Addressable
SFR Address: 0xD0
Bit0
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:
100
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. 1.1
C8051F410/1/2/3
SFR Definition 10.5. 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
Bit
Addressable
SFR Address: 0xE0
Bit0
Bits7–0: ACC: Accumulator.
This register is the accumulator for arithmetic operations.
SFR Definition 10.6. 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
Bit
Addressable
SFR Address: 0xF0
Bit0
Bits7–0: B: B Register.
This register serves as a second accumulator for certain arithmetic operations.
10.3. 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 10.7 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.
The C8051F41x devices feature a low-power SUSPEND mode, which stops the internal oscillator until a
wakening event occurs. See Section “19.1.1. Internal Oscillator Suspend Mode” on page 166.
Rev. 1.1
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10.3.1. 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.
10.3.2. 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.
10.3.3. Suspend Mode
The C8051F41x devices feature a low-power SUSPEND mode, which stops the internal oscillator until a
wakening event occurs. See Section “19.1.1. Internal Oscillator Suspend Mode” on page 166.
SFR Definition 10.7. PCON: Power Control
R/W
R/W
R/W
R/W
R/W
R/W
Reserved Reserved Reserved Reserved Reserved Reserved
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
R/W
R/W
Reset Value
STOP
IDLE
00000000
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.)
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11. Memory Organization and SFRs
The memory organization of the C8051F41x 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 11.1.
PROGRAM/DATA MEMORY
(Flash)
DATA MEMORY (RAM)
INTERNAL DATA ADDRESS SPACE
‘F410/1
0xFF
0x7E00
RESERVED
0x7DFF
0x80
0x7F
Upper 128 RAM
(Indirect Addressing
Only)
(Direct and Indirect
Addressing)
32 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
EXTERNAL DATA ADDRESS SPACE
0x0000
‘F412/3
0x4000
0xFFFF
RESERVED
Same 2048 bytes as from
0x0000 to 0x07FF, wrapped
on 2048-byte boundaries
0x3FFF
16 kB Flash
(In-System
Programmable in 512
Byte Sectors)
0x0000
0x0800
0x07FF
XRAM - 2048 Bytes
(accessible using MOVX
instruction)
0x0000
Figure 11.1. Memory Map
11.1. Program Memory
The CIP-51 core has a 64k-byte program memory space. The C8051F410/1 implement 32k of this program memory space as in-system, re-programmable Flash memory, organized in a contiguous block from
addresses 0x0000 to 0x7DFF. Addresses above 0x7DFF are reserved on the 32 kB devices. The
C8051F412/3 implement 16 kB of Flash from addresses 0x0000 to 0x3FFF.
Program memory is normally assumed to be read-only. However, the C8051F41x 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 “16. Flash Memory” on page 135 for further details.
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11.2. Data Memory
The C8051F41x 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 11.1 illustrates the data memory organization of the C8051F41x.
The C8051F41x family also includes 2048 bytes of on-chip RAM mapped into the external memory
(XDATA) space. This RAM can be accessed using the CIP-51 core’s MOVX instruction. More information
on the XRAM memory can be found in Section “17. External RAM” on page 145.
11.3. 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 10.4. 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.
11.4. 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.
11.5. 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.
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11.6. 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 11.1 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 11.2, for a detailed
description of each register.
Table 11.1. 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
SMB0CN
IP
P0ODEN
IE
P2
SCON0
P1
TCON
P0
0(8)
PCA0L
P0MDIN
PCA0CPL1
XBR0
PCA0MD
REF0CN
REG0CN
SMB0CF
IDA0CN
OSCXCN
CLKSEL
SPI0CFG
SBUF0
TMR3CN
TMOD
SP
1(9)
PCA0H PCA0CPL0 PCA0CPH0 PCA0CPL4 PCA0CPH4
P1MDIN
P2MDIN
IDA1L
IDA1H
EIP1
PCA0CPH1 PCA0CPL2 PCA0CPH2 PCA0CPL3 PCA0CPH3
XBR1
PFE0CN
IT01CF
EIE1
PCA0CPM0 PCA0CPM1 PCA0CPM2 PCA0CPM3 PCA0CPM4
PCA0CPL5 PCA0CPH5 P0SKIP
P1SKIP
P2SKIP
TMR2RLL TMR2RLH
TMR2L
TMR2H PCA0CPM5
SMB0DAT ADC0GTL ADC0GTH ADC0LTL ADC0LTH
ADC0TK
ADC0MX
ADC0CF
ADC0L
ADC0H
OSCICN
OSCICL
IDA1CN
FLSCL
EMI0CN
CLKMUL RTC0ADR RTC0DAT RTC0KEY
SPI0CKR SPI0DAT P0MDOUT P1MDOUT P2MDOUT
CPT1CN
CPT0CN
CPT1MD
CPT0MD
CPT1MX
TMR3RLL TMR3RLH
TMR3L
TMR3H
IDA0L
TL0
TL1
TH0
TH1
CKCON
DPL
DPH
CRC0CN
CRC0IN CRC0DAT
2(A)
3(B)
4(C)
5(D)
6(E)
VDM0CN
EIP2
RSTSRC
EIE2
CRC0FLIP
P0MAT
P1MAT
P0MASK
P1MASK
FLKEY
ONESHOT
CPT0MX
IDA0H
PSCTL
PCON
7(F)
(bit addressable)
Rev. 1.1
105
C8051F410/1/2/3
Table 11.2. Special Function Registers
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
Description
Page
ACC
0xE0
Accumulator
101
ADC0CF
0xBC
ADC0 Configuration
60
ADC0CN
0xE8
ADC0 Control
62
ADC0H
0xBE
ADC0
61
ADC0L
0xBD
ADC0
61
ADC0GTH
0xC4
ADC0 Greater-Than Data High Byte
64
ADC0GTL
0xC3
ADC0 Greater-Than Data Low Byte
64
ADC0LTH
0xC6
ADC0 Less-Than Data High Byte
65
ADC0LTL
0xC5
ADC0 Less-Than Data Low Byte
65
ADC0MX
0xC6
ADC0 Channel Select
59
ADC0TK
0xBA
ADC0 Tracking Mode Select
63
B
0xF0
B Register
101
CKCON
0x8E
Clock Control
237
CLKMUL
0xAB
Clock Multiplier
173
CLKSEL
0xA9
Clock Select
174
CPT0CN
0x9B
Comparator0 Control
86
CPT0MD
0x9D
Comparator0 Mode Selection
88
CPT0MX
0x9F
Comparator0 MUX Selection
87
CPT1CN
0x9A
Comparator1 Control
91
CPT1MD
0x9C
Comparator1 Mode Selection
90
CPT1MX
0x9E
Comparator1 MUX Selection
89
CRC0CN
0x84
CRC0 Control
125
CRC0IN
0x85
CRC0 Data Input
125
CRC0DAT
0x86
CRC0 Data Output
126
CRC0FLIP
0xDF
CRC0 Bit Flip
126
DPH
0x83
Data Pointer High
99
DPL
0x82
Data Pointer Low
99
EIE1
0xE6
Extended Interrupt Enable 1
114
EIE2
0xE7
Extended Interrupt Enable 2
116
EIP1
0xF6
Extended Interrupt Priority 1
115
EIP2
0xF7
Extended Interrupt Priority 2
116
EMI0CN
0xAA
External Memory Interface Control
145
FLKEY
0xB7
Flash Lock and Key
141
FLSCL
0xB6
Flash Scale
142
IDA0H
0x97
Current Mode DAC0 High Byte
71
IDA0L
0x96
Current Mode DAC0 Low Byte
72
IDA0CN
0xB9
Current Mode DAC0 Control
71
IDA1H
0xF5
Current Mode DAC1 High Byte
73
106
Rev. 1.1
C8051F410/1/2/3
Table 11.2. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
Description
Page
IDA1L
0xF4
Current Mode DAC1 Low Byte
73
IDA1CN
0xB5
Current Mode DAC1 Control
72
IE
0xA8
Interrupt Enable
112
IP
0xB8
Interrupt Priority
113
IT01CF
0xE4
INT0/INT1 Configuration
118
ONESHOT
0xAF
Flash Oneshot Period
143
OSCICL
0xB3
Internal Oscillator Calibration
167
OSCICN
0xB2
Internal Oscillator Control
167
OSCXCN
0xB1
External Oscillator Control
171
P0
0x80
Port 0 Latch
155
P0MASK
0xC7
Port 0 Mask
157
P0MAT
0xD7
Port 0 Match
157
P0MDIN
0xF1
Port 0 Input Mode Configuration
155
P0MDOUT
0xA4
Port 0 Output Mode Configuration
156
P0ODEN
0xB0
Port 0 Overdrive
157
P0SKIP
0xD4
Port 0 Skip
156
P1
0x90
Port 1 Latch
158
P1MASK
0xBF
Port 1 Mask
160
P1MAT
0xCF
Port 1 Match
160
P1MDIN
0xF2
Port 1 Input Mode Configuration
158
P1MDOUT
0xA5
Port 1 Output Mode Configuration
159
P1SKIP
0xD5
Port 1 Skip
159
P2
0xA0
Port 2 Latch
161
P2MDIN
0xF3
Port 2 Input Mode Configuration
161
P2MDOUT
0xA6
Port 2 Output Mode Configuration
162
P2SKIP
0xD6
Port 2 Skip
162
PCA0CN
0xD8
PCA Control
261
PCA0CPH0
0xFC
PCA Capture 0 High
264
PCA0CPH1
0xEA
PCA Capture 1 High
264
PCA0CPH2
0xEC
PCA Capture 2 High
264
PCA0CPH3
0xEE
PCA Capture 3 High
264
PCA0CPH4
0xFE
PCA Capture 4 High
264
PCA0CPH5
0xD3
PCA Capture 5 High
264
PCA0CPL0
0xFB
PCA Capture 0 Low
264
PCA0CPL1
0xE9
PCA Capture 1 Low
264
PCA0CPL2
0xEB
PCA Capture 2 Low
264
PCA0CPL3
0xED
PCA Capture 3 Low
264
PCA0CPL4
0xFD
PCA Capture 4 Low
264
Rev. 1.1
107
C8051F410/1/2/3
Table 11.2. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
Description
Page
PCA0CPL5
0xD2
PCA Capture 5 Low
264
PCA0CPM0
0xDA
PCA Module 0 Mode
263
PCA0CPM1
0xDB
PCA Module 1 Mode
263
PCA0CPM2
0xDC
PCA Module 2 Mode
263
PCA0CPM3
0xDD
PCA Module 3 Mode
263
PCA0CPM4
0xDE
PCA Module 4 Mode
263
PCA0CPM5
0xCE
PCA Module 5 Mode
263
PCA0H
0xFA
PCA Counter High
264
PCA0L
0xF9
PCA Counter Low
264
PCA0MD
0xD9
PCA Mode
262
PCON
0x87
Power Control
102
PFE0CN
0xE3
Prefetch Engine Control
119
PSCTL
0x8F
Program Store R/W Control
141
PSW
0xD0
Program Status Word
100
REF0CN
0xD1
Voltage Reference Control
78
REG0CN
0xC9
Voltage Regulator Control
82
RTC0ADR
0xAC
smaRTClock Address
181
RTC0DAT
0xAD
smaRTClock Data
182
RTC0KEY
0xAE
smaRTClock Lock and Key
180
RSTSRC
0xEF
Reset Source Configuration/Status
133
SBUF0
0x99
UART0 Data Buffer
213
SCON0
0x98
UART0 Control
212
SMB0CF
0xC1
SMBus Configuration
197
SMB0CN
0xC0
SMBus Control
199
SMB0DAT
0xC2
SMBus Data
201
SP
0x81
Stack Pointer
98
SPI0CFG
0xA1
SPI Configuration
223
SPI0CKR
0xA2
SPI Clock Rate Control
225
SPI0CN
0xF8
SPI Control
224
SPI0DAT
0xA3
SPI Data
226
TCON
0x88
Timer/Counter Control
235
TH0
0x8C
Timer/Counter 0 High
238
TH1
0x8D
Timer/Counter 1 High
238
TL0
0x8A
Timer/Counter 0 Low
238
TL1
0x8B
Timer/Counter 1 Low
238
TMOD
0x89
Timer/Counter Mode
236
TMR2CN
0xC8
Timer/Counter 2 Control
242
TMR2H
0xCD
Timer/Counter 2 High
243
108
Rev. 1.1
C8051F410/1/2/3
Table 11.2. Special Function Registers (Continued)
SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
Register
Address
Description
Page
TMR2L
0xCC
Timer/Counter 2 Low
243
TMR2RLH
0xCB
Timer/Counter 2 Reload High
243
TMR2RLL
0xCA
Timer/Counter 2 Reload Low
243
TMR3CN
0x91
Timer/Counter 3Control
247
TMR3H
0x95
Timer/Counter 3 High
248
TMR3L
0x94
Timer/Counter 3 Low
248
TMR3RLH
0x93
Timer/Counter 3 Reload High
248
TMR3RLL
0x92
Timer/Counter 3 Reload Low
248
0xFF
VDD Monitor Control
130
VDM0CN
XBR0
0xE1
Port I/O Crossbar Control 0
153
XBR1
0xE2
Port I/O Crossbar Control 1
154
Rev. 1.1
109
C8051F410/1/2/3
12. Interrupt Handler
The C8051F41x family includes an extended interrupt system supporting a total of 18 interrupt sources
with two 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.
12.1. MCU Interrupt Sources and Vectors
The MCUs support 18 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 12.1 on page 111. 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).
12.2. 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 12.1.
12.3. 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
110
Rev. 1.1
C8051F410/1/2/3
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
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)
Y
N
ESMB0
(EIE1.0)
PSMB0
(EIP1.0)
N
N
ERTC0
(EIE1.1)
PRTC0
(EIP1.1)
Y
N
Y
N
Y
N
N
N
N
N
N
N
EWADC0
(EIE1.2)
EADC0
(EIE1.3)
EPCA0
(EIE1.4)
ECP0
(EIE1.5)
ECP1
(EIE1.6)
ET3
(EIE1.7)
EREG0
(EIE2.0)
EMAT
(EIE2.1)
PWADC0
(EIP1.2)
PADC0
(EIP1.3)
PPCA0
(EIP1.4)
PCP0
(EIP1.5)
PCP1
(EIP1.6)
PT3
(EIP1.7)
PREG0
(EIP2.0)
PMAT
(EIP2.1)
Top
External Interrupt 0 (/INT0)
Timer 0 Overflow
External Interrupt 1 (/INT1)
Timer 1 Overflow
0x0003
0x000B
0x0013
0x001B
0
1
2
3
UART0
0x0023
4
Timer 2 Overflow
0x002B
5
SPI0
0x0033
6
SMB0
0x003B
7
smaRTClock
0x0043
8
ADC0 Window
Comparator
0x004B
9
ADC0 End of Conversion
0x0053
10
Programmable Counter
Array
0x005B
11
Comparator0
0x0063
12
Comparator1
0x006B
13
Timer 3 Overflow
0x0073
14
Voltage Regulator Dropout 0x007B
15
N/A
N/A N/A
Port Match
16
N/A
N/A N/A
SI (SMB0CN.0)
ALRM (RTC0CN.2)
OSCFAIL
(RTC0CN.5)
AD0WINT
(ADC0CN.3)
AD0INT (ADC0STA.5)
CF (PCA0CN.7)
CCFn (PCA0CN.n)
CP0FIF (CPT0CN.4)
CP0RIF (CPT0CN.5)
CP1FIF (CPT1CN.4)
CP1RIF (CPT1CN.5)
TF3H (TMR3CN.7)
TF3L (TMR3CN.6)
Rev. 1.1
Priority
Control
Y
Y
Y
Y
0x0000
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)
Enable
Flag
Always
Enabled
EX0 (IE.0)
ET0 (IE.1)
EX1 (IE.2)
ET1 (IE.3)
Reset
0x0083
None
Cleared by HW?
Interrupt Source
Bit addressable?
Table 12.1. Interrupt Summary
N/A N/A
Always
Highest
PX0 (IP.0)
PT0 (IP.1)
PX1 (IP.2)
PT1 (IP.3)
111
C8051F410/1/2/3
12.4. 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 12.1. 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
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
112
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 External Interrupt 1.
0: Disable external interrupt 1.
1: Enable interrupt requests generated by the /INT1 input.
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 External Interrupt 0.
0: Disable external interrupt 0.
1: Enable interrupt requests generated by the /INT0 input.
Rev. 1.1
C8051F410/1/2/3
SFR Definition 12.2. 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
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
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 1 Priority Control.
This bit sets the priority of the External Interrupt 1 interrupt.
0: External Interrupt 1 set to low priority level.
1: External Interrupt 1 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 interrupt.
0: External Interrupt 0 set to low priority level.
1: External Interrupt 0 set to high priority level.
Rev. 1.1
113
C8051F410/1/2/3
SFR Definition 12.3. EIE1: Extended Interrupt Enable 1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
ET3
ECP1
ECP0
EPCA0
EADC0
EWADC0
ERTC0
ESMB0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xE6
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
114
ET3: Enable Timer 3 Interrupt.
This bit sets the masking of the Timer 3 interrupt.
0: Disable Timer 3 interrupts.
1: Enable interrupt requests generated by the TF3L or TF3H flags.
ECP1: Enable Comparator1 (CP1) Interrupt.
This bit sets the masking of the CP1 interrupt.
0: Disable CP1 interrupts.
1: Enable interrupt requests generated by the CP1RIF or CP1FIF flags.
ECP0: Enable Comparator0 (CP0) Interrupt.
This bit sets the masking of the CP0 interrupt.
0: Disable CP0 interrupts.
1: Enable interrupt requests generated by the CP0RIF or CP0FIF flags.
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.
ERTC0: Enable smaRTClock Interrupt.
This bit sets the masking of the smaRTClock interrupt.
0: Disable smaRTClock interrupts.
1: Enable interrupt requests generated by the ALRM and OSCFAIL flag.
ESMB0: Enable SMBus (SMB0) Interrupt.
This bit sets the masking of the SMB0 interrupt.
0: Disable all SMB0 interrupts.
1: Enable interrupt requests generated by SMB0.
Rev. 1.1
C8051F410/1/2/3
SFR Definition 12.4. EIP1: Extended Interrupt Priority 1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
PT3
PCP1
PCP0
PPCA0
PADC0
PWADC0
PRTC0
PSMB0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xF6
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
PT3: Timer 3 Interrupt Priority Control.
This bit sets the priority of the Timer 3 interrupt.
0: Timer 3 interrupts set to low priority level.
1: Timer 3 interrupts set to high priority level.
PCP1: Comparator1 (CP1) Interrupt Priority Control.
This bit sets the priority of the CP1 interrupt.
0: CP1 interrupt set to low priority level.
1: CP1 interrupt set to high priority level.
PCP0: Comparator0 (CP0) Interrupt Priority Control.
This bit sets the priority of the CP0 interrupt.
0: CP0 interrupt set to low priority level.
1: CP0 interrupt set to high priority level.
PPCA0: 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.
PADC0: 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.
PRTC0: smaRTClock Interrupt Priority Control.
This bit sets the priority of the smaRTClock interrupt.
0: smaRTClock interrupt set to low priority level.
1: smaRTClock interrupt set to high priority level.
PSMB0: SMBus (SMB0) Interrupt Priority Control.
This bit sets the priority of the SMB0 interrupt.
0: SMB0 interrupt set to low priority level.
1: SMB0 interrupt set to high priority level.
Rev. 1.1
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C8051F410/1/2/3
SFR Definition 12.5. EIE2: Extended Interrupt Enable 2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
00000000
-
-
-
-
-
-
EMAT
EREG0
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xE7
Bits 7–2: UNUSED. Read = 000000b. Write = don’t care.
Bit 1:
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.
Bit 0:
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.
SFR Definition 12.6. EIP2: Extended Interrupt Priority 2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
-
-
-
-
-
-
PMAT
PREG0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xF7
Bits 7–2: UNUSED. Read = 000000b. Write = don’t care.
Bit 1:
EMAT: 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.
Bit 0:
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.
116
Rev. 1.1
C8051F410/1/2/3
12.5. 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 “24.1. Timer 0 and Timer 1” on page 231) 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 12.7).
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
“18.1. Priority Crossbar Decoder” on page 149 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. 1.1
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C8051F410/1/2/3
SFR Definition 12.7. 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 24.1. “TCON: Timer Control” on page 235 for INT0/1 edge- or level-sensitive interrupt selection.
Bit 7:
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).
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
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
118
/INT0 Port Pin
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
Rev. 1.1
C8051F410/1/2/3
13. Prefetch Engine
The C8051F41x family of devices incorporate a 2-byte prefetch engine. Due to Flash access time specifications, the prefetch engine is necessary for full-speed (50 MHz) code execution. Instructions are read
from Flash memory two bytes at a time by the prefetch engine, and given to the CIP-51 processor core to
execute. When running linear code (code without any jumps or branches), the prefetch engine allows
instructions to be executed at full speed. When a code branch occurs, the processor may be stalled for up
to two clock cycles while the next set of code bytes is retrieved from Flash memory. The FLRT bit
(FLSCL.4) determines how many clock cycles are used to read each set of two code bytes from Flash.
When operating from a system clock of 25 MHz or less, the FLRT bit should be set to ‘0’ so that the
prefetch engine takes only one clock cycle for each read. When operating with a system clock of greater
than 25 MHz (up to 50 MHz), the FLRT bit should be set to ‘1’, so that each prefetch code read lasts for
two clock cycles.
SFR Definition 13.1. PFE0CN: Prefetch Engine Control
R
R
R/W
R
R
R
R
PFEN
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
FLBWE
00100000
Bit0
SFR Address: 0xE3
Bits 7–6: Unused. Read = 00b; Write = Don’t Care
Bit 5:
PFEN: Prefetch Enable.
This bit enables the prefetch engine.
0: Prefetch engine is disabled.
1: Prefetch engine is enabled.
Bits 4–1: Unused. Read = 0000b; Write = Don’t Care
Bit 0:
FLBWE: Flash Block Write Enable.
This bit allows block writes to Flash memory from software.
0: Each byte of a software Flash write is written individually.
1: Flash bytes are written in groups of two.
Note: The prefetch engine should be disabled when changes to FLRT are made. See Section
“16. Flash Memory” on page 135.
Rev. 1.1
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C8051F410/1/2/3
NOTES:
120
Rev. 1.1
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14. Cyclic Redundancy Check Unit (CRC0)
C8051F41x devices include a cyclic redundancy check unit (CRC0) that can perform a CRC using a 16-bit
or 32-bit polynomial. CRC0 accepts a stream of 8-bit data written to the CRC0IN register. CRC0 posts the
16-bit or 32-bit result to an internal register. The internal result register may be accessed indirectly using
the CRC0PNT bits and CRC0DAT register, as shown in Figure 14.1. CRC0 also has a bit reverse register
for quick data manipulation.
8
CRC0CN
CRC0IN
CRC0SEL
CRC0INIT
CRC0VAL
CRC0PNT1
CRC0PNT0
CRC Engine
32
RESULT
8
8
8
8
4 to 1 MUX
8
CRC0DAT
Figure 14.1. CRC0 Block Diagram
14.1. 16-bit CRC Algorithm
The C8051F41x CRC unit calculates the 16-bit CRC MSB-first, using a poly of 0x1021. The following
describes the 16-bit CRC algorithm performed by the hardware:
Step 1. XOR the most-significant byte of the current CRC result with the input byte. If this is the
first iteration of the CRC unit, the current CRC result will be the set initial value (0x0000 or
0xFFFF).
Step 2a. If the MSB of the CRC result is set, left-shift the CRC result, and then XOR the CRC
result with the polynomial (0x1021).
Step 2b. If the MSB of the CRC result is not set, left-shift the CRC result.
Step 3. Repeat at Step 2a for the number of input bits (8).
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For example, the 16-bit 'F41x CRC algorithm can be described by the following code:
unsigned short UpdateCRC (unsigned short CRC_acc, unsigned char CRC_input)
{
unsigned char i;
// loop counter
#define POLY 0x1021
// Create the CRC "dividend" for polynomial arithmetic (binary arithmetic
// with no carries)
CRC_acc = CRC_acc ^ (CRC_input << 8);
// "Divide" the poly into the dividend using CRC XOR subtraction
// CRC_acc holds the "remainder" of each divide
//
// Only complete this division for 8 bits since input is 1 byte
for (i = 0; i < 8; i++)
{
// Check if the MSB is set (if MSB is 1, then the POLY can "divide"
// into the "dividend")
if ((CRC_acc & 0x8000) == 0x8000)
{
// if so, shift the CRC value, and XOR "subtract" the poly
CRC_acc = CRC_acc << 1;
CRC_acc ^= POLY;
}
else
{
// if not, just shift the CRC value
CRC_acc = CRC_acc << 1;
}
}
// Return the final remainder (CRC value)
return CRC_acc;
}
The following table lists several input values and the associated outputs using the 16-bit 'F41x CRC algorithm (an initial value of 0xFFFF is used):
Table 14.1. Example 16-bit CRC Outputs
122
Input
Output
0x63
0xBD35
0x8C
0xB1F4
0x7D
0x4ECA
0xAA, 0xBB, 0xCC
0x6CF6
0x00, 0x00, 0xAA, 0xBB, 0xCC
0xB166
Rev. 1.1
C8051F410/1/2/3
14.2. 32-bit CRC Algorithm
The C8051F41x CRC unit calculates the 32-bit CRC using a poly of 0x04C11DB7. The CRC-32 algorithm
is "reflected", meaning that all of the input bytes and the final 32-bit output are bit-reversed in the processing engine. The following is a description of a simplified CRC algorithm that produces results identical to
the hardware:
Step 1. XOR the least-significant byte of the current CRC result with the input byte. If this is the
first iteration of the CRC unit, the current CRC result will be the set initial value
(0x00000000 or 0xFFFFFFFF).
Step 2. Right-shift the CRC result.
Step 3. If the LSB of the CRC result is set, XOR the CRC result with the reflected polynomial
(0xEDB88320).
Step 4. Repeat at Step 2 for the number of input bits (8).
For example, the 32-bit 'F41x CRC algorithm can be described by the following code:
unsigned long UpdateCRC (unsigned long CRC_acc, unsigned char CRC_input)
{
unsigned char i; // loop counter
#define POLY 0xEDB88320 // bit-reversed version of the poly 0x04C11DB7
// Create the CRC "dividend" for polynomial arithmetic (binary arithmetic
// with no carries)
CRC_acc = CRC_acc ^ CRC_input;
// "Divide" the poly into the dividend using CRC XOR subtraction
// CRC_acc holds the "remainder" of each divide
//
// Only complete this division for 8 bits since input is 1 byte
for (i = 0; i < 8; i++)
{
// Check if the MSB is set (if MSB is 1, then the POLY can "divide"
// into the "dividend")
if ((CRC_acc & 0x00000001) == 0x00000001)
{
// if so, shift the CRC value, and XOR "subtract" the poly
CRC_acc = CRC_acc >> 1;
CRC_acc ^= POLY;
}
else
{
// if not, just shift the CRC value
CRC_acc = CRC_acc >> 1;
}
}
// Return the final remainder (CRC value)
return CRC_acc;
}
The following table lists several input values and the associated outputs using the 32-bit 'F41x CRC algorithm (an initial value of 0xFFFFFFFF is used):
Rev. 1.1
123
C8051F410/1/2/3
Table 14.2. Example 32-bit CRC Outputs
Input
Output
0x63
0xF9462090
0xAA, 0xBB, 0xCC
0x41B207B3
0x00, 0x00, 0xAA, 0xBB, 0xCC
0x78D129BC
14.3. Preparing for a CRC Calculation
To prepare CRC0 for a CRC calculation, software should select the desired polynomial and set the initial
value of the result. Two polynomials are available: 0x1021 (16-bit) and 0x04C11DB7 (32-bit). The CRC0
result may be initialized to one of two values: 0x00000000 or 0xFFFFFFFF. The following steps can be
used to initialize CRC0.
Step 1. Select a polynomial (Set CRC0SEL to ‘0’ for 32-bit or ‘1’ for 16-bit).
Step 2. Select the initial result value (Set CRC0VAL to ‘0’ for 0x00000000 or ‘1’ for 0xFFFFFFFF).
Step 3. Set the result to its initial value (Write ‘1’ to CRC0INIT).
14.4. Performing a CRC Calculation
Once CRC0 is initialized, the input data stream is sequentially written to CRC0IN, one byte at a time. The
CRC0 result is automatically updated after each byte is written.
14.5. Accessing the CRC0 Result
The internal CRC0 result is 32-bits (CRC0SEL = 0b) or 16-bits (CRC0SEL = 1b). The CRC0PNT bits
select the byte that is targeted by read and write operations on CRC0DAT and increment after each read or
write. The calculation result will remain in the internal CRC0 result register until it is set, overwritten, or
additional data is written to CRC0IN.
14.6. CRC0 Bit Reverse Feature
CRC0 includes hardware to reverse the bit order of each bit in a byte as shown in Figure 14.2. Each byte
of data written to CRC0FLIP is read back bit reversed. For example, if 0xC0 is written to CRC0FLIP, the
data read back is 0x03.
CRC0FLIP
Write
CRC0FLIP
Read
Figure 14.2. Bit Reverse Register
124
Rev. 1.1
C8051F410/1/2/3
SFR Definition 14.1. CRC0CN: CRC0 Control
R
R
R
-
-
-
Bit7
Bit6
Bit5
R/W
W
R/W
CRC0SEL CRC0INIT CRC0VAL
Bit4
Bit3
Bit2
R/W
R/W
CRC0PNT
Bit1
Reset Value
00000000
Bit0
SFR Address: 0x84
Bits 7–5: UNUSED. Read = 0b. Write = don’t care.
Bit 4:
CRC0SEL: CRC0 Polynomial Select Bit.
0: CRC0 uses the 32-bit polynomial 0x04C11DB7 for calculating the CRC result.
1: CRC0 uses the 16-bit polynomial 0x1021 for calculating the CRC result.
Bit 3:
CRC0INIT: CRC0 Result Initialization Bit.
Writing a ‘1’ to this bit initializes the entire CRC result based on CRC0VAL.
Bit 2:
CRC0VAL: CRC0 Set Value Select Bit
This bit selects the set value of the CRC result.
0: CRC result is set to 0x00000000 on write of ‘1’ to CRC0INIT.
1: CRC result is set to 0xFFFFFFFF on write of ‘1’ to CRC0INIT.
Bits 1–0: CRC0PNT. CRC0 Result Pointer.
These bits specify which byte of the CRC result will be read/written on the next access to
CRC0DAT. The value of these bits will auto-increment upon each read or write.
For CRC0SEL = 0:
00: CRC0DAT accesses bits 7–0 of the 32-bit CRC result.
01: CRC0DAT accesses bits 15–8 of the 32-bit CRC result.
10: CRC0DAT accesses bits 23–16 of the 32-bit CRC result.
11: CRC0DAT accesses bits 31–24 of the 32-bit CRC result.
For CRC0SEL = 1:
00: CRC0DAT accesses bits 7–0 of the 16-bit CRC result.
01: CRC0DAT accesses bits 15–8 of the 16-bit CRC result.
10: CRC0DAT accesses bits 7–0 of the 16-bit CRC result.
11: CRC0DAT accesses bits 15–8 of the 16-bit CRC result.
SFR Definition 14.2. CRC0IN: CRC0 Data Input
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: 0x85
Bits 7–0: CRC0IN: CRC Data Input
Each write to CRCIN results in the written data being computed into the existing CRC result.
Rev. 1.1
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C8051F410/1/2/3
SFR Definition 14.3. CRC0DAT: CRC0 Data Output
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: 0x86
Bits 7–0: CRC0DAT: Indirect CRC Result Data Bits.
Each operation performed on CRC0DAT targets the CRC result bits pointed to by
CRC0PNT.
SFR Definition 14.4. CRC0FLIP: CRC0 Bit Flip
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: 0xDF
Bits 7–0: CRC0FLIP: CRC Bit Flip.
Any byte written to CRC0FLIP is read back in a bit-reversed order, i.e. the written LSB
becomes the MSB. For example:
If 0xC0 is written to CRC0FLIP, the data read back will be 0x03.
If 0x05 is written to CRC0FLIP, the data read back will be 0xA0.
126
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15. 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 “19. Oscillators” on page 165 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 “25.3. Watchdog Timer Mode” on page 257 details the use of the Watchdog Timer).
Program execution begins at location 0x0000.
VDD
Comparator 0
+
-
smaRTClock
'0'
Enable
(wired-OR)
/RST
RTC0RE
Missing
Clock
Detector
(oneshot)
EN
Reset
Funnel
PCA
WDT
(Software Reset)
SWRSF
EN
MCD
Enable
Px.x
+
-
C0RSEF
System
Clock
Illegal Flash
Operation
WDT
Enable
Px.x
Power On
Reset
Supply
Monitor
CIP-51
Microcontroller
Core
System Reset
Extended Interrupt
Handler
Figure 15.1. Reset Sources
Rev. 1.1
127
C8051F410/1/2/3
15.1. 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 15.2 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 15.2. Power-On and VDD Monitor Reset Timing
128
Rev. 1.1
C8051F410/1/2/3
15.2. Power-Fail Reset / VDD Monitor
When the VDD Monitor is selected as a reset source and 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 15.2). 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 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 (approximately 5 µs).
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 15.2 for VDD monitor timing; note that the reset delay is not incurred after a VDD monitor reset.
See Table 15.1 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. 1.1
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C8051F410/1/2/3
SFR Definition 15.1. VDM0CN: VDD Monitor Control
R/W
R
R/W
R
R
R
R
R
Reset Value
VDMEN VDDSTAT VDMLVL Reserved Reserved Reserved Reserved Reserved 1v000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xFF
Bit7:
VDMEN: 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 15.2). 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 15.1 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 recommended for any system
that includes code that writes to and/or erases Flash.
Bits4–0: Reserved. Read = Variable. Write = don’t care.
15.3. 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 15.1 for complete RST pin
specifications. The PINRSF flag (RSTSRC.0) is set on exit from an external reset.
15.4. 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.
15.5. Comparator0 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-inverting
130
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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.
15.6. 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 “25.3. Watchdog Timer Mode” on
page 257; 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.
15.7. 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
“16.3. Security Options” on page 137).
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.
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15.8. smaRTClock (Real Time Clock) Reset
The smaRTClock can generate a system reset on two events: smaRTClock Oscillator Fail or smaRTClock
Alarm. The smaRTClock Oscillator Fail event occurs when the smaRTClock Missing Clock Detector is
enabled and the smaRTClock clock is below approximately 20 kHz. A smaRTClock alarm event occurs
when the smaRTClock Alarm is enabled and the smaRTClock timer value matches the ALARMn registers.
The smaRTClock can be configured as a reset source by writing a ‘1’ to the RTC0RE flag (RSTSRC.7).
The state of the RST pin is unaffected by this reset.
15.9. 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.
132
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SFR Definition 15.2. RSTSRC: Reset Source
R/W
R
R/W
RTC0RE FERROR C0RSEF
Bit7
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: For bits that act as both reset source enables (on a write) and reset indicator flags (on a read),
read-modify-write instructions read and modify the source enable only. [This applies to bits:
RTC0RE, C0RSEF, SWRSF, MCDRSF, PORSF].
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
RTC0RE: smaRTClock (Real Time Clock) Reset Enable and Flag.
0: Read: Source of last reset was not a smaRTClock alarm or oscillator fail event.
Write: smaRTClock is not a reset source.
1: Read: Source of last reset was a smaRTClock alarm or oscillator fail event.
Write: smaRTClock is a reset source.
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 VDM0CN (SFR Definition 15.1)
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.
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Table 15.1. Reset Electrical Characteristics
–40 to +85 °C unless otherwise specified. Typical values are given at 25 ºC.
Parameter
Min
Typ
Max
—
—
—
—
50
800
—
—
—
—
40
400
RST Input High Voltage
0.7 x VIO
—
—
V
RST Input Low Voltage
—
—
0.3 x VIO
V
VIO = 2.0 V
—
150
—
VIO = 5.0 V
—
70
—
VDD Monitor Threshold (VRST-LOW)
1.9
1.95
2.0
V
VDD Monitor Threshold (VRST-HIGH)
2.25
2.3
2.35
V
RST Output Low Voltage
RST Input Pullup Impedance
Conditions
VIO = 2.0 V:
IOL = 70 µA
IOL = 8.5 mA
VIO = 4.0 V:
IOL = 70 µA
IOL = 8.5 mA
Units
mV
kΩ
Missing Clock Detector Timeout
Time from last system clock
rising edge to reset initiation
50
350
650
µs
Reset Time Delay
Delay between release of any
reset source and code execution at location 0x0000
—
—
180
µs
Minimum RST Low Time to Generate a System Reset
20
—
—
µs
VDD Monitor Supply Current
—
0.7
70
µA
—
—
1
ms
VDD Ramp Time
134
VDD = 0 V to VDD = VRST V
Rev. 1.1
C8051F410/1/2/3
16. 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 16.2 for complete Flash memory electrical characteristics.
16.1. 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 “26. C2
Interface” on page 265. For detailed guidelines on writing or erasing Flash from firmware, please see
Section “16.4. Flash Write and Erase Guidelines” on page 139.
To ensure the integrity of the Flash contents, the on-chip VDD Monitor must be enabled to the
higher setting (VDMLVL = '1') in any system that includes code that writes and/or erases Flash
memory from software. Furthermore, there should be no delay between enabling the VDD Monitor
and enabling the VDD Monitor as a reset source. Any attempt to write or erase Flash memory while
the VDD Monitor disabled will cause a Flash Error device reset.
16.1.1. 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 16.2.
16.1.2. 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.
Rev. 1.1
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16.1.3. Flash Write Procedure
Bytes in Flash memory can be written one byte at a time, or in groups of two. The FLBWE bit in register
PFE0CN (SFR Definition 13.1) controls whether a single byte or a block of two bytes is written to Flash
during a write operation. When FLBWE is cleared to ‘0’, the Flash will be written one byte at a time. When
FLBWE is set to ‘1’, the Flash will be written in two-byte blocks. Block writes are performed in the same
amount of time as single-byte writes, which can save time when storing large amounts of data to Flash
memory.
During a single-byte write to Flash, bytes are written individually, and a Flash write will be performed after
each MOVX write instruction. The recommended procedure for writing Flash in single bytes is:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
Step 8.
Disable interrupts.
Clear the FLBWE bit (register PFE0CN) to select single-byte write mode.
Write '0000' to FLSCL.3–0.
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 9. Clear the PSWE bit.
Step 10. Re-enable interrupts.
Steps 3–9 must be repeated for each byte to be written.
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.
Step 7.
Step 8.
Disable interrupts.
Set the FLBWE bit (register PFE0CN) to select block write mode.
Write '0000' to FLSCL.3–0.
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 9. Clear the PSWE bit (register PSCTL).
Step 10. Write the first key code to FLKEY: 0xA5.
Step 11. Write the second key code to FLKEY: 0xF1.
Step 12. Set the PSWE bit (register PSCTL).
Step 13. Clear the PSEE bit (register PSCTL).
Step 14. Using the MOVX instruction, write the second data byte to the odd block location (ending
in 1b).
Step 15. Clear the PSWE bit (register PSCTL).
Step 16. Re-enable interrupts.
Steps 3-15 must be repeated for each block to be written.
136
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16.2. 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.
16.3. 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 the example below for an C8051F410.
Security Lock Byte:
1’s Complement:
Flash pages locked:
11111101b
00000010b
3 (First two Flash pages + Lock Byte Page)
0x0000 to 0x03FF (first two Flash pages) and
Addresses locked:
0x7C00 to 0x7DFF (Lock Byte Page)
C8051F410/1
C8051F412/3
Reserved
Reserved
0x4000
0x7E00
0x7DFF
Lock Byte
Lock Byte
Locked when any
other Flash pages are
locked
0x7DFE
0x7C00
0x3FFF
0x3FFE
0x3E00
Flash memory organized
in 512-byte pages
Unlocked Flash Pages
Unlocked Flash Pages
Access limit set
according to the Flash
security lock byte
0x0000
0x0000
Figure 16.1. Flash Program Memory Map
Rev. 1.1
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C8051F410/1/2/3
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 16.1 summarizes the Flash security
features of the 'F41x devices.
Table 16.1. Flash Security Summary
Action
C2 Debug
Interface
User Firmware executing from:
an unlocked page
a locked page
Permitted
Permitted
Permitted
Not Permitted
FEDR
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
FEDR
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
FEDR
Permitted
Permitted
FEDR
FEDR
Only C2DE
FEDR
FEDR
Lock additional pages
(change '1's to '0's in the Lock Byte)
Not Permitted
FEDR
FEDR
Unlock individual pages
(change '0's to '1's in the Lock Byte)
Not Permitted
FEDR
FEDR
Read, Write or Erase Reserved Area
Not Permitted
FEDR
FEDR
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)
Erase page containing Lock Byte - Unlock all pages
(if any page is locked)
C2DE - C2 Device Erase (Erases all Flash pages including the page containing the Lock Byte)
FEDR - 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.
138
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16.4. 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.
To help prevent the accidental modification of Flash by firmware, the VDD Monitor must be enabled and
enabled as a reset source on C8051F41x devices for the Flash to be successfully modified. If either the
VDD Monitor or the VDD Monitor reset source is not enabled, a Flash Error Device Reset will be
generated when the firmware attempts to modify the Flash.
The following guidelines are recommended for any system that contains routines which write or erase
Flash from code.
16.4.1. 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 VRST and re-asserts /RST if VDD
drops below VRST.
3. Keep the on-chip VDD Monitor enabled 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.
Note: On C8051F41x devices, both the VDD Monitor and the VDD Monitor reset source must
be enabled to write or erase Flash without generating a Flash Error Device Reset.
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, but "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.
Rev. 1.1
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16.4.2. 16.4.2 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 both 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 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.
16.4.3. 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.
140
Rev. 1.1
C8051F410/1/2/3
SFR Definition 16.1. 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 16.2. 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. 1.1
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C8051F410/1/2/3
16.5. Flash Read Timing
On reset, the C8051F41x Flash read timing is configured for operation with system clocks up to 25 MHz. If
the system clock will not be increased above 25 MHz, then the Flash timing registers may be left at their
reset value.
For every Flash read or fetch, the system provides an internal Flash read strobe to the Flash memory. The
Flash read strobe lasts for one or two system clock cycles, based on FLRT (FLSCL.4). If the system
clock is greater than 25 MHz, the FLRT bit must be set to logic 1, otherwise data read or fetched from
Flash may not represent the actual contents of Flash.
When the Flash read strobe is asserted, Flash memory is active. When it is de-asserted, Flash memory is
in a low power state. The Flash read strobe does not need to be asserted for longer than 80 ns in order for
Flash reads and fetches to be reliable. For system clocks greater than 12.5 MHz (but less than 25 MHz),
the Flash read strobe width is limited by the system clock period. For system clocks less than 12.5 MHz,
the Flash read strobe is limited by a programmable one shot with a default period of 80 ns (1/12.5 MHz).
This is a power saving feature that is very beneficial for very slow system clocks (e.g. 32.768 kHz where
the system clock period is greater than 30,000 ns).
For additional power savings, the one shot can be programmed to values less than 80 ns. The one shot
can be trimmed according the equation in the ONESHOT register description in Figure 16.4. The one shot
period must not be programmed less than the minimum read cycle time specified in Table 16.2.
The recommended procedure for updating FLRT or the ONESHOT period is:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Select SYSCLK to 25 MHz or less.
Disable the prefetch engine (PFEN = ‘0’ in PFE0CN register).
Clear FLRT to ‘0’ (FLSCL register).
Set the ONESHOT period bits.
Set FLRT to ‘1’ if SYSCLK > 25 MHz.
Enable the prefetch engine (PFEN = ‘1’ in PFE0CN register).
SFR Definition 16.3. FLSCL: Flash Scale
R/W
R/W
R/W
Reserved Reserved Reserved
Bit7
Bit6
Bit5
R/W
FLRT
Bit4
R/W
R/W
R/W
R/W
Reset Value
Reserved Reserved Reserved Reserved 00000011
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xB6
Bits7–5: RESERVED. Read = 000b. Must Write 000b.
Bit 4:
FLRT: Flash Read Time Control.
This bit should be programmed to the smallest allowed value, according to the system clock
speed.
0: SYSCLK < 25 MHz (Flash read strobe is one system clock).
1: SYSCLK > 25 MHz (Flash read strobe is two system clocks).
Bits3–0: RESERVED. Must Write 0000b.
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SFR Definition 16.4. ONESHOT: Flash Oneshot Period
R
R
R
R
-
-
-
-
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
R/W
PERIOD
Bit3
Bit2
Reset Value
00001111
Bit1
Bit0
SFR Address: 0xAF
Bits7–4: UNUSED. Read = 0000b. Write = don’t care.
Bits3–0: PERIOD: Oneshot Period Control Bits.
These bits limit the internal Flash read strobe width as follows. When the Flash read strobe
is de-asserted, the Flash memory enters a low-power state for the remainder of the system
clock cycle. These bits have no effect when the system clocks is greater than 12.5 MHz and
FLRT = 0.
FLASH RDMAX = 5ns + ( PERIOD × 5ns )
Table 16.2. Flash Electrical Characteristics
VDD = 2.0 to 2.75 V; –40 to +85 ºC unless otherwise specified. Typical values are given at 25 ºC.
Parameter
Flash Size
Endurance
Conditions
Min
C8051F410/1
32768*
C8051F412/3
16384
VDD is 2.2 V or greater
20 k
Typ
Max
Units
—
—
bytes
90 k
—
Erase/Write
Erase Cycle Time
FLSCL.3–0 written to '0000'
16
20
24
ms
Write Cycle Time
FLSCL.3–0 written to '0000'
38
46
57
µs
40
—
—
ns
2.25
—
—
V
Read Cycle Time
VDD
Write/Erase Operations
*Note: 512 bytes at addresses 0x7E00 to 0x7FFF are reserved.
Rev. 1.1
143
C8051F410/1/2/3
NOTES:
144
Rev. 1.1
C8051F410/1/2/3
17. External RAM
The C8051F41x devices include 2048 bytes of RAM mapped into the external data memory space. All of
these address locations may be accessed using the external move instruction (MOVX) and the data
pointer (DPTR), or using MOVX indirect addressing mode. If the MOVX instruction is used with an 8-bit
address operand (such as @R1), then the high byte of the 16-bit address is provided by the External Memory Interface Control Register (EMI0CN as shown in SFR Definition 17.1). Note: the MOVX instruction is
also used for writes to the Flash memory. See Section “16. Flash Memory” on page 135 for details. The
MOVX instruction accesses XRAM by default.
For a 16-bit MOVX operation (@DPTR), the upper 5-bits of the 16-bit external data memory address word
are "don't cares.” As a result, the RAM is mapped modulo style over the entire 64 k external data memory
address range. For example, the XRAM byte at address 0x0000 is shadowed at addresses 0x0800,
0x1000, 0x1800, 0x2000, etc. This is a useful feature when performing a linear memory fill, as the address
pointer doesn't have to be reset when reaching the RAM block boundary.
SFR Definition 17.1. EMI0CN: External Memory Interface Control
R/W
R/W
R/W
R/W
R/W
-
-
-
-
-
Bit7
Bit6
Bit5
Bit4
Bit3
R/W
R/W
R/W
PGSEL
Bit2
Bit1
Reset Value
00000000
Bit0
SFR Address: 0xAA
Bits 7–3: UNUSED. Read = 00000b. Write = don’t care.
Bits 2–0: PGSEL: XRAM Page Select.
The EMI0CN register provides the high byte of the 16-bit external data memory address
when using an 8-bit MOVX command, effectively selecting a 256-byte page of RAM. Since
the upper (unused) bits of the register are always zero, the PGSEL determines which page
of XRAM is accessed.
For Example: If EMI0CN = 0x01, addresses 0x0100 through 0x01FF will be accessed.
Rev. 1.1
145
C8051F410/1/2/3
NOTES:
146
Rev. 1.1
C8051F410/1/2/3
18. Port Input/Output
Digital and analog resources are available through up to 24 I/O pins. Port pins are organized as three bytewide Ports. Each of the Port pins can be defined as general-purpose I/O (GPIO) or analog input/output;
Port pins P0.0 - P2.7 can be assigned to one of the internal digital resources as shown in Figure 18.3. 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 18.3 and Figure 18.4). The registers XBR0 and XBR1, defined in SFR
Definition 18.1 and SFR Definition 18.2, are used to select internal digital functions.
Port I/Os on P0 are 5 V tolerant over the operating range of VIO. Port I/Os on P1 and P2 should not be
driven above VIO or they will sink current. Figure 18.2 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 =
0,1,2). Complete Electrical Specifications for Port I/O are given in Table 18.1 on page 163.
P0MASK, P0MATCH
P1MASK, P1MATCH
Registers
XBR0, XBR1,
PnSKIP Registers
PnMDOUT,
PnMDIN Registers
Priority
Decoder
Highest
Priority
UART
4
(Internal Digital Signals)
SPI
2
SMBus
CP0
CP1
Outputs
Digital
Crossbar
8
7
T0, T1
2
8
8
(Port Latches)
P0
8
4
SYSCLK
PCA
Lowest
Priority
2
P0
I/O
Cells
P0.0
P1
I/O
Cells
P1.0
P2
I/O
Cell
P2.0
P0.7
P1.7
P2.7
P2.3–2.6 available on
C8051F410/2
(P0.0-P0.7)
8
P1
(P1.0-P1.7)
8
P2
(P2.0-P2.7)
Figure 18.1. Port I/O Functional Block Diagram
Rev. 1.1
147
C8051F410/1/2/3
/WEAK-PULLUP
VIO
PUSH-PULL
/PORT-OUTENABLE
VIO
(WEAK)
PORT
PAD
PORT-OUTPUT
GND
Analog Select
ANALOG INPUT
PORT-INPUT
Figure 18.2. Port I/O Cell Block Diagram
148
Rev. 1.1
C8051F410/1/2/3
18.1. Priority Crossbar Decoder
The Priority Crossbar Decoder (Figure 18.3) 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 P1.1 for the external
oscillator, P1.2 for VREF, P0.6 for the external CNVSTR signal, P0.0 for IDA0, P0.1 for IDA1, 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 18.3 shows the Crossbar Decoder priority with no Port pins
skipped (P0SKIP, P1SKIP, P2SKIP = 0x00); Figure 18.4 shows the Crossbar Decoder priority with the
XTAL1 (P1.0) and XTAL2 (P1.1) pins skipped (P1SKIP = 0x03).
P0
SF Signa ls i0
PIN I/O
0
i1
1
2
3
P2
P1
4
5
cnvstr
6 7
x 1 x 2 vre f
0 1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
0
0
0
0
0
0
0
0
0
0
TX0
RX0
SCK
MISO
MOSI
(*4-W ire SPI Only)
NSS*
SDA
SCL
CP0
CP0A
CP1
CP1A
/SYSCLK
CEX0
CEX1
CEX2
CEX3
CEX4
CEX5
ECI
T0
T1
0
0
0
0
0
0
P0SKIP[0:7]
0
0
0
0
0
0
0
P1SKIP[0:7]
P2SKIP[0:7]
Figure 18.3. Crossbar Priority Decoder with No Pins Skipped
Rev. 1.1
149
C8051F410/1/2/3
i1
1
2
3
P2
P1
P0
SF Signals i0
PIN I/O
0
4
cnvstr
5 6 7
x 1 x 2 vre f
0 1 2 3
4
5
6
7
0
1
2
3
4
5
6
7
0
0
0
TX0
RX0
SCK
MISO
MOSI
(*4-W ire SPI Only)
NSS*
SDA
SCL
CP0
CP0A
CP1
CP1A
/SYSCLK
CEX0
CEX1
CEX2
CEX3
CEX4
CEX5
ECI
T0
T1
0
0
0
0
0
0
P0SKIP[0:7]
0
0
1
1
0
0
0
0
0
P1SKIP[0:7] = 0x 03
0
0
0
0
0
0
P2SKIP[0:7]
Port pin potentially assignable to peripheral
SF Signals Special Function Signals are not assigned by the crossbar. W hen these signals are enabled,
the CrossBar must be manually configured to skip their corresponding port pins.
Figure 18.4. Crossbar Priority Decoder with Crystal Pins Skipped
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 P0.4; UART
RX0 is always assigned to P0.5. Standard Port I/Os appear contiguously starting at P0.0 after prioritized
functions and skipped pins are assigned.
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.
150
Rev. 1.1
C8051F410/1/2/3
18.2. 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). If the pin is in analog mode, a '1' must also be written to the
corresponding Port Latch.
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 port pins in analog mode must have a '1' set in the
corresponding Port Latch register. All pins default to digital inputs on reset. See SFR Definition 18.4 for the
PnMDIN register details.
Important Note: Port 0 pins are 5 V tolerant across the operating range of VIO. Figure 18.5 shows the
input current range of P0 pins when overdriven above VIO (when VIO is 3.3 V nominal). There are two overdrive modes for Port 0: Normal and High-Impedance. When the corresponding bit in P0ODEN is logic 0,
Normal Overdrive Mode is selected and the port pin requires 150 µA peak overdrive current when its voltage reaches approximately VIO + 0.7 V. When the corresponding bit in P0ODEN is logic 1, High-Impedance Overdrive Mode is selected and the port pin does not require any additional overdrive current. Pins
configured to High-Impedance Overdrive Mode consume slightly more power from VIO than pins configured to Normal Overdrive Mode. Note that Port 1 and Port 2 pins cannot be overdriven above VIO and
have the same behavior as P0 in Normal Mode.
Rev. 1.1
151
C8051F410/1/2/3
Normal Mode
P0ODEN.x = 0
V IO
V IO+0.7
V test (V)
IVtest (µA)
0
-10
V DD
-150
V IO
I/O
Cell
P0.x
pin
IVtest
High-Impedance Mode
P0ODEN.x = 1
+
-
V test
IVtest (µA)
10
0
V IO -0.2
V IO+0.2
V test (V)
-10
Figure 18.5. Port 0 Input Overdrive Current Range
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. The only
exception to this is the SMBus (SDA, SCL) pins, which are configured as open-drain regardless of the
PnMDOUT settings. 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.
152
Rev. 1.1
C8051F410/1/2/3
SFR Definition 18.1. 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
CP1AE
CP1E
CP0AE
CP0E
SYSCKE
SMB0E
SPI0E
URT0E
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xE1
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
CP1AE: Comparator1 Asynchronous Output Enable
0: Asynchronous CP1 unavailable at Port pin.
1: Asynchronous CP1 routed to Port pin.
CP1E: Comparator1 Output Enable
0: CP1 unavailable at Port pin.
1: CP1 routed to Port pin.
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.
SMB0E: SMBus I/O Enable
0: SMBus I/O unavailable at Port pins.
1: SMBus I/O routed to Port pins.
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 P0.4 and P0.5.
Rev. 1.1
153
C8051F410/1/2/3
SFR Definition 18.2. XBR1: Port I/O Crossbar Register 1
R/W
R/W
WEAKPUD XBARE
Bit7
Bit6
R/W
R/W
R/W
T1E
T0E
ECIE
Bit5
Bit4
Bit3
R/W
R/W
R/W
PCA0ME
Bit2
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.
Bits2–0: PCA0ME: PCA Module I/O Enable Bits.
000: All PCA I/O unavailable at Port pins.
001: CEX0 routed to Port pin.
010: CEX0, CEX1 routed to Port pins.
011: CEX0, CEX1, CEX2 routed to Port pins.
100: CEX0, CEX1, CEX2, CEX3 routed to Port pins.
101: CEX0, CEX1, CEX2, CEX3, CEX4 routed to Port pins.
110: CEX0, CEX1, CEX2, CEX3, CEX4, CEX5 routed to Port pins.
111: Reserved.
18.3. 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-P2 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.
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
154
Rev. 1.1
C8051F410/1/2/3
(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 “19.1.1. Internal
Oscillator Suspend Mode” on page 166 for more information.
SFR Definition 18.3. 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 18.4. 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. In order for the P0.n pin to be
in analog input mode, there MUST be a '1' in the Port Latch register corresponding to
that pin.
1: Corresponding P0.n pin is not configured as an analog input.
Rev. 1.1
155
C8051F410/1/2/3
SFR Definition 18.5. 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 18.6. 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.
156
Rev. 1.1
C8051F410/1/2/3
SFR Definition 18.7. 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 18.8. 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.
SFR Definition 18.9. P0ODEN: Port0 Overdrive Mode
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: 0xB0
Bits7–0: High Impedance Overdrive Mode Enable Bits for P0.7–P0.0 (respectively).
Port pins configured to High-Impedance Overdrive Mode do not require additional overdrive
current, although selecting this mode results in a slight increase in supply current. Port pins
configured to Normal Overdrive Mode require approximately 150 µA of input overdrive current when the voltage at the pin reaches VIO+0.7 V.
0: Corresponding P0.n pin is configured to Normal Overdrive Mode.
1: Corresponding P0.n pin is configured to High-Impedance Overdrive Mode.
Rev. 1.1
157
C8051F410/1/2/3
SFR Definition 18.10. 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 18.11. 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. In order for the P1.n pin to be
in analog input mode, there MUST be a '1' in the Port Latch register corresponding to
that pin.
1: Corresponding P1.n pin is not configured as an analog input.
158
Rev. 1.1
C8051F410/1/2/3
SFR Definition 18.12. 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 18.13. 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.
Rev. 1.1
159
C8051F410/1/2/3
SFR Definition 18.14. 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 18.15. 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.
160
Rev. 1.1
C8051F410/1/2/3
SFR Definition 18.16. P2: Port2
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
P2.7
P2.6
P2.5
P2.4
P2.3
P2.2
P2.1
P2.0
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Bit
Addressable
SFR Address: 0xA0
Bits7–0: P2.[7:0]
Write - Output appears on I/O pins per Crossbar Registers.
0: Logic Low Output.
1: Logic High Output (high impedance if corresponding P2MDOUT.n bit = 0).
Read - Always reads ‘0’ if selected as analog input in register P2MDIN. Directly reads Port
pin when configured as digital input.
0: P2.n pin is logic low.
1: P2.n pin is logic high.
SFR Definition 18.17. P2MDIN: Port2 Input Mode
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xF3
Bits7–0: Analog Input Configuration Bits for P2.7–P2.0 (respectively).
Port pins configured as analog inputs have their weak pullup, digital driver, and digital
receiver disabled.
0: Corresponding P2.n pin is configured as an analog input. In order for the P2.n pin to be
in analog input mode, there MUST be a '1' in the Port Latch register corresponding to
that pin.
1: Corresponding P2.n pin is not configured as an analog input.
Rev. 1.1
161
C8051F410/1/2/3
SFR Definition 18.18. P2MDOUT: Port2 Output Mode
R
R
R
R
R
R
R
R/W
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xA6
Bits7–0: Output Configuration Bits for P2.7–P2.0 (respectively): ignored if corresponding bit in register P2MDIN is logic 0.
0: Corresponding P2.n Output is open-drain.
1: Corresponding P2.n Output is push-pull.
SFR Definition 18.19. P2SKIP: Port2 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: 0xD6
Bits7–0: P2SKIP[7:0]: Port2 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 P2.n pin is not skipped by the Crossbar.
1: Corresponding P2.n pin is skipped by the Crossbar.
162
Rev. 1.1
C8051F410/1/2/3
Table 18.1. Port I/O DC Electrical Characteristics
VIO = 2.0 to 5.25 V, –40 to +85 °C unless otherwise specified. Typical values are given at 25 ºC.
Parameters
Min
Typ
Max
IOH = –3 mA, Port I/O push-pull
VIO – 0.5
—
—
IOH = –70 µA, Port I/O push-pull
VIO – 50 mV
—
—
—
—
—
—
50
800
—
—
—
—
40
400
Input High Voltage
VIO x 0.7
—
—
V
Input Low Voltage
—
—
VIO x 0.3
V
—
< 0.1
±1
µA
—
120
—
kΩ
Output High Voltage
Output Low Voltage
Input Leakage Current
Conditions
VIO = 2.0 V:
IOL = 70 µA
IOL = 8.5 mA
VIO = 4.0 V:
IOL = 70 µA
IOL = 8.5 mA
Weak Pullup Off
Weak Pullup Impedance
Rev. 1.1
Units
V
mV
163
C8051F410/1/2/3
NOTES:
164
Rev. 1.1
C8051F410/1/2/3
19. Oscillators
C8051F41x devices include a programmable internal oscillator, an external oscillator drive circuit, and a
Clock Multiplier. The internal oscillator can be enabled/disabled and calibrated using the OSCICN and
OSCICL registers, as shown in Figure 19.1. The system clock (SYSCLK) can be derived from the internal
oscillator, external oscillator circuit, or smaRTClock oscillator. The clock multiplier can produce three possible base outputs which can be scaled by a programmable factor of 1, 2/3, 2/4 (or 1/2), 2/5, 2/6 (or 1/3), or
2/7: Internal Oscillator x 2, External Oscillator x 2, or External Oscillator x 4. Oscillator electrical specifications are given in Table 19.1 on page 175.
OSCICN
XTAL2
IFCN2
IFCN1
IFCN0
IOSCEN
IFRDY
SUSPEND
Option 3
VDD
CLKSEL
CLKSL1
CLKSL0
OSCICL
Option 2
XTAL2
EN
IOSC
Programmable
Internal Clock
Generator
Option 1
n
XTAL1
EXOSC
Input
Circuit
OSC
SYSCLK
XTAL2
XTLVLD
x4
n
EXOSC / 2
XFCN2
XFCN1
XFCN0
IOSC
XTLVLD
XOSCMD2
XOSCMD1
XOSCMD0
Option 4
XTAL2
IOSC/2
EXOSC
OSCXCN
Clock Multiplier
MULEN
MULINIT
MULRDY
MULDIV2
MULDIV1
MULDIV0
MULSEL1
MULSEL0
10MΩ
smaRTClock
Oscillator
CLKMUL
Figure 19.1. Oscillator Diagram
19.1. Programmable Internal Oscillator
All C8051F41x 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 register, shown in SFR
Definition 19.2. On C8051F41x devices, OSCICL is factory calibrated to obtain a 24.5 MHz frequency.
Electrical specifications for the precision internal oscillator are given in Table 19.1 on page 175. 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. 1.1
165
C8051F410/1/2/3
19.1.1. 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.
Comparator 1 enabled and output is logic 0.
smaRTClock Oscillator Fail Event.
smaRTClock Alarm Event.
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.
166
Rev. 1.1
C8051F410/1/2/3
SFR Definition 19.1. OSCICN: Internal Oscillator Control
R/W
R
R/W
IOSCEN
IFRDY
SUSPEND
Bit7
Bit6
Bit5
R
R
R/W
R/W
R/W
Reset Value
-
-
IFCN2
IFCN1
IFCN0
11000000
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0xB2
Bit7:
IOSCEN: Internal Oscillator Enable Bit.
0: Internal Oscillator Disabled.
1: Internal Oscillator Enabled.
Bit6:
IFRDY: Internal Oscillator Frequency Ready Flag.
0: Internal Oscillator is not running at programmed frequency.
1: Internal Oscillator is running at programmed frequency.
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.
Bits4–3: 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.
SFR Definition 19.2. 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
OSCICL
Bit3
Reset Value
Varies
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 C8051F41x devices, the reset
value is factory calibrated to generate an internal oscillator frequency of 24.5 MHz.
Rev. 1.1
167
C8051F410/1/2/3
19.2. 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 19.1. 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 19.1. 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 19.3. 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
P1.0 and P1.1 are used as XTAL1 and XTAL2 respectively. When the external oscillator drive circuit is
enabled in capacitor, RC, or CMOS clock mode, Port pin P1.1 is used as XTAL2. The Port I/O Crossbar
should be configured to skip the Port pins used by the oscillator circuit; see Section “18.1. Priority Crossbar Decoder” on page 149 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 (with ‘1's in the corresponding Port Latch). In CMOS clock mode, the associated pin should be configured as a digital input. See Section “18.2. Port I/O Initialization” on page 151 for details on Port
input mode selection.
The frequency of the external oscillator can be measured with respect to the smaRTClock Oscillator using
Timer 2 or Timer 3. Section “24.2.3. External/smaRTClock Capture Mode” on page 241 shows how this
can be accomplished.
19.2.1. Clocking Timers Directly Through the External Oscillator
The external oscillator source divided by eight is a clock option for the timers (Section “24. Timers” on
page 231) and the Programmable Counter Array (PCA) (Section “25. Programmable Counter Array
(PCA0)” on page 249). 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.
19.2.2. 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 19.1, Option 1. The External Oscillator Frequency Control value (XFCN)
should be chosen from the Crystal column of the table in SFR Definition 19.3. For example, a 12 MHz crystal requires an XFCN setting of 111b.
168
Rev. 1.1
C8051F410/1/2/3
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.
Step 7.
Force the XTAL1 and XTAL2 pins low by writing 0's to the port latch.
Configure XTAL1 and XTAL2 as analog inputs.
Release the crystal pins by writing ‘1's to the port latch.
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 32.768 kHz with a recommended load capacitance of 12.5 pF should
use the configuration shown in Figure 19.1, 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 19.2.
22 pF
XTAL1
32.768 kHz
10 MΩ
XTAL2
22 pF
Figure 19.2. 32.768 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.
Rev. 1.1
169
C8051F410/1/2/3
19.2.3. 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 19.1, 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 19.3, 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.
19.2.4. External Capacitor Example
If a capacitor is used as an external oscillator for the MCU, the circuit should be configured as shown in
Figure 19.1, 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 = 2.0 V and f = 75 kHz:
f = KF / (C x VDD)
0.075 MHz = KF / (C x 2.0)
Since the frequency of roughly 75 kHz is desired, select the K Factor from the table in SFR Definition 19.3
as KF = 7.7:
0.075 MHz = 7.7 / (C x 2.0)
C x 2.0 = 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.
170
Rev. 1.1
C8051F410/1/2/3
SFR Definition 19.3. OSCXCN: External Oscillator Control
R
R/W
R/W
R/W
R/W
XTLVLD XOSCMD2 XOSCMD1 XOSCMD0 Reserved
Bit7
Bit6
Bit5
Bit4
R/W
R/W
R/W
Reset Value
XFCN2
XFCN1
XFCN0
00000000
Bit2
Bit1
Bit3
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
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
Crystal Mode (Circuit from Figure 19.1, Option 1; XOSCMD = 11x)
Choose XFCN value to match crystal or resonator frequency.
RC Mode (Circuit from Figure 19.1, 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 19.1, 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
Rev. 1.1
171
C8051F410/1/2/3
19.3. Clock Multiplier
The Clock Multiplier generates an output clock which is 4 times the input clock frequency scaled by a programmable factor of 1, 2/3, 2/4 (or 1/2), 2/5, 2/6 (or 1/3), or 2/7. The Clock Multiplier’s input can be
selected from the external oscillator, or the internal or external oscillators divided by 2. This produces three
possible base outputs which can be scaled by a programmable factor: Internal Oscillator x 2, External
Oscillator x 2, or External Oscillator x 4. See Section 19.4 for details on system clock selection.
The Clock Multiplier is configured via the CLKMUL register (SFR Definition 19.4). The procedure for configuring and enabling the Clock Multiplier is as follows:
1.
2.
3.
4.
5.
6.
7.
Reset the Multiplier by writing 0x00 to register CLKMUL.
Select the Multiplier input source via the MULSEL bits.
Select the Multiplier output scaling factor via the MULDIV bits
Enable the Multiplier with the MULEN bit (CLKMUL | = 0x80).
Delay for >5 µs.
Initialize the Multiplier with the MULINIT bit (CLKMUL | = 0xC0).
Poll for MULRDY => ‘1’.
Important Note: When using an external oscillator as the input to the Clock Multiplier, the external
source must be enabled and stable before the Multiplier is initialized. See Section 19.4 for details
on selecting an external oscillator source.
The Clock Multiplier allows faster operation of the CIP-51 core and is intended to generate an output frequency between 25 and 50 MHz. The clock multiplier can also be used with slow input clocks. However, if
the clock is below the minimum Clock Multiplier input frequency (FCMmin) specified in Table 19.1, the generated clock will consist of four fast pulses followed by a long delay until the next input clock rising edge.
The average frequency of the output is equal to 4x the input, but the instantaneous frequency may be
faster. See Figure 19.3 for more information.
if FCM in > FCM min
FCM in
FCM out
if FCM in< FCM min
FCM in
FCM out
Figure 19.3. Example Clock Multiplier Output
172
Rev. 1.1
C8051F410/1/2/3
SFR Definition 19.4. CLKMUL: Clock Multiplier Control
R/W
MULEN
Bit7
R/W
R
R/W
MULINIT MULRDY
Bit6
Bit5
R/W
R/W
R/W
Bit2
Bit1
MULDIV
Bit4
Bit3
R/W
MULSEL
Reset Value
00000000
Bit0
SFR Address: 0xAB
Note:
The maximum SYSCLK is 50 MHz, so the Clock Multiplier output should be scaled accordingly.
Bit7:
MULEN: Clock Multiplier Enable
0: Clock Multiplier disabled.
1: Clock Multiplier enabled.
Bit6:
MULINIT: Clock Multiplier Initialize
This bit should be a ‘0’ when the Clock Multiplier is enabled. Once enabled, writing a ‘1’ to
this bit will initialize the Clock Multiplier. The MULRDY bit reads ‘1’ when the Clock Multiplier
is stabilized.
Bit5:
MULRDY: Clock Multiplier Ready
This read-only bit indicates the status of the Clock Multiplier.
0: Clock Multiplier not ready.
1: Clock Multiplier ready (locked).
Bits4–2: MULDIV: Clock Multiplier Output Scaling Factor
These bits scale the Clock Multiplier output.
000: Clock Multiplier Output scaled by a factor of 1.
001: Clock Multiplier Output scaled by a factor of 1.
010: Clock Multiplier Output scaled by a factor of 1.
011: Clock Multiplier Output scaled by a factor of 2/3*.
100: Clock Multiplier Output scaled by a factor of 2/4 (or 1/2).
101: Clock Multiplier Output scaled by a factor of 2/5*.
110: Clock Multiplier Output scaled by a factor of 2/6 (or 1/3).
111: Clock Multiplier Output scaled by a factor of 2/7*.
*Note: The Clock Multiplier Output duty cycle is not 50% for these settings.
Bits1–0: MULSEL: Clock Multiplier Input Select
These bits select the clock supplied to the Clock Multiplier.
MULSEL
Selected Input Clock
00
01
10
11
Internal Oscillator / 2
External Oscillator
External Oscillator / 2
Internal Oscillator
Rev. 1.1
Clock Multiplier Output
for MULDIV = 000b
Internal Oscillator x 2
External Oscillator x 4
External Oscillator x 2
Internal Oscillator x 4
173
C8051F410/1/2/3
19.4. 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[1:0] bits in register CLKSEL select which oscillator source is used as the system clock.
CLKSL[1:0] must be set to 01b 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, external oscillator, smaRTClock oscillator, and Clock Multiplier, as long as the selected clock source is enabled and has
settled.
SFR Definition 19.5. CLKSEL: Clock Select
R
R
-
-
Bit7
Bit6
R/W
R/W
CLKDIV
Bit5
Bit4
R
R/W
-
Reserved
Bit3
Bit2
R/W
R/W
CLKSL
Bit1
Reset Value
00000000
Bit0
SFR Address: 0xA9
Bits7–6: Unused. Read = 00b; Write = don’t care.
Bits5–4: CLKDIV1–0: Output /SYSCLK Divide Value
These bits can be used to pre-divide the /SYSCLK output before it is sent to a port pin
through the Crossbar.
00: Output will be SYSCLK.
01: Output will be SYSCLK/2.
10: Output will be SYSCLK/4.
11: Output will be SYSCLK/8.
Bit3:
Unused. Read = 0b; Write = don’t care.
Bit2:
Reserved. Read = 0b; Must write 0b.
Bits1–0: CLKSL1–0: System Clock Select
These bits select the system clock source.
CLKSL
00
01
10
11
174
Selected Clock
Internal Oscillator (as determined by the
IFCN bits in register OSCICN)
External Oscillator
Clock Multiplier
smaRTClock Oscillator
Rev. 1.1
C8051F410/1/2/3
Table 19.1. Oscillator Electrical Characteristics
–40 to +85 °C unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Units
Internal Oscillator Frequency
Reset Frequency
24
24.5
25
MHz
Internal Oscillator Supply
Current (from VDD)
OSCICN.7 = 1
—
400
—
µA
Minimum Clock Multiplier Input
Frequency (FCMmin)
T = 25 °C
—
1.6
—
MHz
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NOTES:
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20. smaRTClock (Real Time Clock)
C8051F41x devices include a low power smaRTClock Peripheral (Real Time Clock). The smaRTClock has
a dedicated 32 kHz oscillator that can be configured for use with or without a crystal, a 47-bit smaRTClock
timer with alarm, a backup supply regulator and 64 bytes of battery-backed SRAM. When the backup supply voltage (VRTC-BACKUP) is powered, the smaRTClock peripheral remains fully functional if the core supply voltage (VDD) is lost.
The smaRTClock allows a maximum of 137 year 47-bit independent time-keeping when used with a
32.768 kHz Watch Crystal and backup supply voltage of at least 1V. The switchover logic powers smaRTClock from the backup supply when the voltage at VRTC-BACKUP is greater than VDD. The smaRTClock
Alarm and Missing Clock Detector can interrupt the CIP-51, wake the internal oscillator from SUSPEND
mode, or generate a device reset if the smaRTClock timer reaches a pre-set value or the oscillator stops.
XTAL3
XTAL4
smaRTClock
smaRTClock Oscillator
smaRTClock State Machine
Interrupt
64B
Backup RAM
Backup
Regulator
Switchover
Logic
Internal
Registers
Interface
Registers
CAPTUREn
RTC0CN
RTC0XCN
ALARMn
RAMADDR
RAMDATA
RTC0KEY
CIP-51 CPU
47-Bit
smaRTClock
Timer
RTC0ADR
RTC0DAT
VDD
VRTC-BACKUP
Figure 20.1. smaRTClock Block Diagram
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20.1. smaRTClock Interface
The smaRTClock Interface consists of three registers: RTC0KEY, RTC0ADR, and RTC0DAT. These interface registers are located on the CIP-51’s SFR map and provide access to the smaRTClock internal registers listed in Table 20.1. The smaRTClock internal registers can only be accessed indirectly through the
smaRTClock Interface.
20.1.1. smaRTClock Lock and Key Functions
The smaRTClock Interface is protected with a lock and key function. The smaRTClock Lock and Key Register (RTC0KEY) must be written with the correct key codes, in sequence, before writes and reads to
RTC0ADR and RTC0DAT may be performed. The key codes are: 0xA5, 0xF1. There are no timing restrictions, but the key codes must be written in order. If the key codes are written out of order, the wrong codes
are written, or an invalid read or write is attempted, further writes and reads to RTC0ADR and RTC0DAT
will be disabled until the next system reset. Once the smaRTClock interface is unlocked, software may perform accesses of the smaRTClock registers until an invalid access, the interface is locked, or a system
reset.
Reading the RTC0KEY register at any time will provide the smaRTClock Interface status and will not interfere with the sequence that is being written. The RTC0KEY register description in SFR Definition 20.1 lists
the definition of each status code.
20.1.2. Using RTC0ADR and RTC0DAT to Access smaRTClock Internal Registers
The smaRTClock internal registers can be read and written using RTC0ADR and RTC0DAT. The
RTC0ADR register selects the smaRTClock internal register that will be targeted by subsequent reads or
writes. Prior to each read or write, BUSY (RTC0ADR.7) should be checked to make sure the smaRTClock
Interface is not busy performing another read or write operation. A smaRTClock Write operation is initiated
by writing to the RTC0DAT register. Below is an example of writing to a smaRTClock internal register.
Step 1. Poll BUSY (RTC0ADR.7) until it returns a ‘0’.
Step 2. Write 0x06 to RTC0ADR. This selects the internal RTC0CN register at smaRTClock
Address 0x06.
Step 3. Write 0x00 to RTC0DAT. This operation writes 0x00 to the internal RTC0CN register.
An smaRTClock Read operation is initiated by setting the smaRTClock Interface Busy bit. This transfers
the contents of the internal register selected by RTC0ADR to RTC0DAT. The transferred data will remain in
RTC0DAT until the next read or write operation. Below is an example of reading a smaRTClock internal
register.
Step 1. Poll BUSY (RTC0ADR.7) until it returns a ‘0’.
Step 2. Write 0x06 to RTC0ADR. This selects the internal RTC0CN register at smaRTClock
Address 0x06.
Step 3. Write ‘1’ to BUSY. This initiates the transfer of data from RTC0CN to RTC0DAT.
Step 4. Poll BUSY (RTC0ADR.7) until it returns a ‘0’.
Step 5. Read data from RTC0DAT. This data is a copy of the RTC0CN register.
Note: The RTC0ADR and RTC0DAT registers will retain their state upon a device reset.
20.1.3. smaRTClock Interface Autoread Feature
When Autoread is enabled, each read from RTC0DAT initiates the next indirect read operation on the
smaRTClock internal register selected by RTC0ADR. Software should set the BUSY bit once at the begin-
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ning of each series of consecutive reads. Software must check if the smaRTClock Interface is busy prior to
reading RTC0DAT. Autoread is enabled by setting AUTORD (RTC0ADR.6) to logic 1.
20.1.4. RTC0ADR Autoincrement Feature
For ease of reading and writing the 48-bit CAPTURE and ALARM values, RTC0ADR automatically increments after each read or write to a CAPTUREn or ALARMn register. This speeds up the process of setting
an alarm or reading the current smaRTClock timer value.
Table 20.1. smaRTClock Internal Registers
smaRTClock smaRTClock
Address
Register
Register Name
Description
0x00 - 0x05
CAPTUREn
smaRTClock Capture
Registers
Six Registers used for setting the 47-bit
smaRTClock timer or reading its current
value. The LSB of CAPTURE0 is not used.
0x06
RTC0CN
smaRTClock Control
Register
Controls the operation of the smaRTClock
State Machine.
0x07
RTC0XCN
smaRTClock Oscillator
Control Register
Controls the operation of the smaRTClock
Oscillator.
0x08–0x0D
ALARMn
smaRTClock Alarm
Registers
Six registers used to set or read the 47-bit
smaRTClock alarm value. The LSB of
ALARM0 is not used.
0x0E
RAMADDR
smaRTClock Backup RAM Used as an index to the 64 byte smaRTClock
Indirect Address Register backup RAM.
0x0F
RAMDATA
smaRTClock Backup RAM Used to read or write the byte pointed to by
RAMADDR.
Indirect Data Register
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SFR Definition 20.1. RTC0KEY: smaRTClock Lock and Key
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: 0xAE
Bits 7–0: RTC0STATE. smaRTClock State Bits
Read:
0x00: smaRTClock Interface is locked.
0x01: smaRTClock Interface is locked. First key code (0xA5) has been written, waiting for
second key code.
0x02: smaRTClock Interface is unlocked. First and second key codes (0xA5, 0xF1) have
been written.
0x03: smaRTClock Interface is disabled until the next system reset.
Write:
When RTC0STATE = 0x00 (locked), writing 0xA5 followed by 0xF1 unlocks the smaRTClock
Interface.
When RTC0STATE = 0x01 (waiting for second key code), writing any value other than the
second key code (0xF1) will change RTC0STATE to 0x03 and disable the smaRTClock
Interface until the next system reset.
When RTC0STATE = 0x02 (unlocked), any write to RTC0KEY will lock the smaRTClock
Interface.
When RTC0STATE = 0x03 (disabled), writes to RTC0KEY have no effect.
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SFR Definition 20.2. RTC0ADR: smaRTClock Address
R/W
BUSY
Bit7
R/W
R/W
AUTORD VREGEN
Bit6
Bit5
R/W
R/W
SHORT
Bit4
R/W
R/W
R/W
RTC0ADDR
Bit3
Bit2
Bit1
Reset Value
Variable
Bit0
SFR Address: 0xAC
Bit 7:
BUSY: smaRTClock Interface Busy bit.
Writing a ‘1’ to this bit initiates a smaRTClock indirect read operation. This bit is automatically cleared by hardware when the operation is complete.
0: smaRTClock Interface is not busy.
1: smaRTClock Interface is busy performing a read or write operation.
Bit 6:
AUTORD: smaRTClock Interface Auto Read Enable.
0: BUSY must be written manually for each smaRTClock indirect read operation.
1: The next smaRTClock indirect read operation is initiated when RTC0DAT is read by software.
Bit 5:
VREGEN: Backup Supply Voltage Regulator Enable.
This bit is automatically set to 1b when VRTC-BACKUP > VDD.
0: Backup Supply Voltage Regulator Disabled (smaRTClock powered from VDD).
1: Force Backup Supply Voltage Regulator Enabled (smaRTClock powered from VRTCBACKUP).
Bit 4:
SHORT: Short Read/Write Timing Enable.
0: smaRTClock reads and writes are 4 system clocks wide.
1: smaRTClock reads and writes are 1 system clock wide.
Note: Increasing the speed of the smaRTClock reads and writes may also slightly increase
power consumption.
Bits 3–0: RTC0ADDR: smaRTClock Address Bits
These bits select the smaRTClock internal register that is targeted by reads/writes to
RTC0DAT.
RTC0ADDR
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
smaRTClock Internal Register
CAPTURE0
CAPTURE1
CAPTURE2
CAPTURE3
CAPTURE4
CAPTURE5
RTC0CN
RTC0XCN
ALARM0
ALARM1
ALARM2
ALARM3
ALARM4
ALARM5
RAMADDR
RAMDATA
Note: The RTC0ADDR bits increment after each indirect read/write operation that
targets a CAPTUREn or ALARMn internal register.
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SFR Definition 20.3. RTC0DAT: smaRTClock Data
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
Variable
SFR Address: 0xAD
Note: Software should avoid read modify write instructions when writing values to RTC0DAT.
Bits 7–0: RTC0DAT. smaRTClock Data Bits
Holds data transferred to/from the internal smaRTClock register selected by RTC0ADR.
20.2. smaRTClock Clocking Sources
The smaRTClock peripheral is clocked from its own timebase, independent of SYSCLK. The RTCCLK
timebase is derived from the smaRTClock oscillator circuit. This oscillator has two modes of operation:
Crystal Mode, and Self-Oscillate Mode. The oscillation frequency is 32.768 kHz in Crystal Mode and can
be configured to roughly 20 kHz or 40 kHz in Self-Oscillate Mode. The frequency of the smaRTClock oscillator can be measured with respect to another oscillator using Timer 2 or Timer 3. Section
“24.2.3. External/smaRTClock Capture Mode” on page 241 shows how this can be accomplished.
Note: The smaRTClock clock can be selected as system clock and routed to a port pin. See SFR
Definition 19.5. “CLKSEL: Clock Select” on page 174 and Section “18. Port Input/Output” on page 147.
20.2.1. Using the smaRTClock Oscillator in Crystal Mode
When using Crystal Mode, a 32.768 kHz crystal should be connected between XTAL3 and XTAL4. No
other external components are required. The following steps show how to start the smaRTClock crystal
oscillator in software:
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Set smaRTClock to Crystal Mode (XMODE = 1).
Optional. Enable Automatic Gain Control (AGCEN = 1).
Optional. Enable smaRTClock Bias Doubling (BIASX2 = 1).
Enable power to the smaRTClock oscillator circuit (RTC0EN = 1).
Poll the smaRTClock Clock Valid Bit (CLKVLD) until the crystal oscillator stabilizes.
Optional. Clear BIASX2 to ‘0’ after the oscillator stabilizes to conserve power.
20.2.2. Using the smaRTClock Oscillator in Self-Oscillate Mode
When using Self-Oscillate Mode, the XTAL3 and XTAL4 pins should be shorted together. The following
steps show how to configure smaRTClock for use in Self-Oscillate Mode:
Step 1. Set smaRTClock to Self-Oscillate Mode (XMODE = 0).
Step 2. Set the desired oscillation frequency:
For oscillation at about 20 kHz, set BIASX2 = 0.
For oscillation at about 40 kHz, set BIASX2 = 1.
Step 3. The oscillator starts oscillating instantaneously.
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20.2.3. Automatic Gain Control (Crystal Mode Only)
Automatic Gain Control is enabled by setting AGCEN (RTC0XCN.7) to a logic 1. When enabled, the
smaRTClock oscillator trims the oscillation amplitude to save power. This mode is useful for preserving
battery life in systems where oscillator performance is not critical and external conditions are stable.
Note: Setting the AGCEN to a logic 1 in self-oscillator mode can lead to drastic changes in the smaRTClock oscillator frequency.
20.2.4. smaRTClock Bias Doubling
The smaRTClock Bias Doubling is enabled by setting BIASX2 (RTC0XCN.5) to 1b. When enabled, the
bias current to smaRTClock is doubled allowing for more robust oscillator performance. When the smaRTClock oscillator is in Self-Oscillate mode, the oscillation frequency is increased from 20 to 40 kHz. When
operating in Crystal Mode, the oscillator is less likely to be affected by external conditions when
BIASX2 = ‘1’. Enabling Bias Doubling increases the power consumption of smaRTClock; therefore, it is not
recommended for use in power-critical systems.
20.2.5. smaRTClock Missing Clock Detector
The smaRTClock Missing Clock Detector is a one-shot circuit enabled by setting MCLKEN (RTC0CN.6) to
a logic 1. When the smaRTClock Missing Clock Detector is enabled, OSCFAIL (RTC0CN.5) is set by hardware if RTCCLK remains high or low for more than 50 µs. A smaRTClock Missing Clock detector timeout
triggers three events:
1. Awakening the internal oscillator from Suspend Mode.
2. smaRTClock Interrupt (If the smaRTClock Interrupt is enabled).
3. MCU reset (If smaRTClock is enabled as a reset source).
Note: The smaRTClock Missing Clock Detector should be disabled when making changes to the oscillator
settings in RTC0XCN.
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Internal Register Definition 20.4. RTC0CN: smaRTClock Control
R/W
R/W
R/W
R/W
R/W
RTC0EN MCLKEN OSCFAIL RTC0TR RTC0AEN
Bit7
Bit6
Bit5
Bit4
Bit3
R/W
ALRM
Bit2
R/W
R/W
RTC0SET RTC0CAP Variable
Bit1
Bit0
Note: This register is not an SFR. It can only be accessed indirectly through RTC0ADR and RTC0DAT.
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
184
Reset Value
smaRTClock
Address:
0x06
RTC0EN: smaRTClock Enable Bit.
0: smaRTClock bias and crystal oscillator disabled. smaRTClock is powered from VDD only.
1: smaRTClock bias and crystal oscillator enabled. smaRTClock can switch to the backup
battery if VDD fails.
MCLKEN: smaRTClock Missing Clock Detector Enable Bit.
When enabled, the smaRTClock missing clock detector sets the OSCFAIL bit if the smaRTClock clock frequency falls below approximately 20 kHz.
0: smaRTClock missing clock detector disabled.
1: smaRTClock missing clock detector enabled.
OSCFAIL: smaRTClock Clock Fail Flag.
Set by hardware when a missing clock detector timeout occurs. When the smaRTClock
Interrupt is enabled, setting this bit causes the CPU to vector to the smaRTClock interrupt
service routine. This bit is not automatically cleared by hardware.
RTC0TR: smaRTClock Timer Run Control.
0: smaRTClock timer holds its current value.
1: smaRTClock timer increments every smaRTClock clock period.
RTC0AEN: smaRTClock Alarm Enable.
0: smaRTClock alarm events disabled.
1: smaRTClock alarm events enabled.
ALRM: smaRTClock Alarm Event Flag.
Set by hardware when the smaRTClock timer value is greater than or equal to the value of
the ALARMn registers. When the smaRTClock Interrupt is enabled, setting this bit causes
the CPU to vector to the smaRTClock interrupt service routine. This bit is not automatically
cleared by hardware.
RTC0SET: smaRTClock Set Bit.
Writing a ‘1’ to this bit causes the 47-bit value in CAPTUREn registers to be transferred to
the smaRTClock timer. This bit is automatically cleared by hardware once the transfer is
complete.
RTC0CAP: smaRTClock Capture Bit.
Writing a ‘1’ to this bit causes the 47-bit smaRTClock timer value to be transferred to the
CAPTUREn registers. This bit is automatically cleared by hardware once the transfer is
complete.
Rev. 1.1
C8051F410/1/2/3
Internal Register Definition 20.5. RTC0XCN: smaRTClock Oscillator Control
R/W
R/W
R/W
R
R
R
R
R
AGCEN
XMODE
BIASX2
CLKVLD
-
-
-
VBATEN
Variable
Bit0
smaRTClock
Address:
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Note: This register is not an SFR. It can only be accessed indirectly through RTC0ADR and RTC0DAT.
Reset Value
0x07
Bit 7:
AGCEN: Crystal Oscillator Automatic Gain Control Enable Bit (Crystal Mode only).
0: Automatic Gain Control disabled.
1: Automatic Gain Control enabled.
Bit 6:
XMODE: smaRTClock Mode Select Bit.
This bit selects whether smaRTClock will be used with or without a crystal.
0: smaRTClock is configured to Self-Oscillate Mode.
1: smaRTClock is configured to Crystal Mode.
Bit 5:
BIASX2: smaRTClock Bias Double Enable Bit.
0: smaRTClock Bias Current Doubling is disabled.
1: smaRTClock Bias Current Doubling is enabled.
Bit 4:
CLKVLD: smaRTClock Clock Valid Bit.
Set by hardware when the smaRTClock crystal oscillator is nearly stable. This bit always
reads 1b when smaRTClock is used in Self-Oscillate Mode (XMODE = 0). This bit should be
checked at least 1 ms after enabling the smaRTClock oscillator circuit and should not be
used for an oscillator fail detect (use OSCFAIL in RTC0CN instead).
Bits 3–1: UNUSED. Read = 000b. Write = don’t care.
Bit 0:
VBATEN: smaRTClock VBAT Indicator.
Note: This bit always reads 1b when smaRTClock is disabled (RTC0EN = 0).
For smaRTClock enabled (RTC0EN = 1):
0: smaRTClock is powered from VDD.
1: smaRTClock is powered from the VRTC-BACKUP supply.
20.3. smaRTClock Timer and Alarm Function
The smaRTClock timer is a 47-bit counter that, when running (RTC0TR = 1), is incremented every RTCCLK cycle. The timer has an alarm function that can be set to generate an interrupt, reset the MCU, or
release the internal oscillator from Suspend Mode at a specific time.
20.3.1. Setting and Reading the smaRTClock Timer Value
The 47-bit smaRTClock timer can be set or read using the six CAPTUREn internal registers. Note that the
timer does not need to be stopped before reading or setting its value. The following steps can be used to
set the timer value:
Step 1. Write the desired 47-bit set value to the CAPTUREn registers (the LSB of CAPTURE0 is
not used).
Step 2. Write ‘1’ to RTC0SET. This will transfer the contents of the CAPTUREn registers to the
timer.
Step 3. Operation is complete when RTC0SET is cleared to ‘0’ by hardware.
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The following steps can be used to read the current timer value:
Step 1. Write ‘1’ to RTC0CAP. This will transfer the contents of the timer to the CAPTUREn
registers (the LSB of the smaRTClock timer will be found in CAPTURE0.1).
Step 2. Poll RTC0CAP until it is cleared to ‘0’ by hardware.
Step 3. A snapshot of the timer value can be read from the CAPTUREn registers
20.3.2. Setting a smaRTClock Alarm
The smaRTClock Alarm function compares the 47-bit value of smaRTClock Timer to the value of the
ALARMn registers. An alarm event is triggered if the smaRTClock timer is greater than or equal to the
ALARMn registers. If the smaRTClock Interrupt is enabled, the CIP-51 will vector to the smaRTClock Interrupt Service Routine when an alarm event occurs. If smaRTClock is enabled as a reset source, the MCU
will be reset when an alarm event occurs. Also, the internal oscillator will awaken from suspend mode on a
smaRTClock alarm event.
The following steps can be used to set up a smaRTClock Alarm:
Step 1. Disable smaRTClock Alarm Events (RTC0AEN = 0).
Step 2. Set the ALARMn registers to the desired value.
Step 3. Enable smaRTClock Alarm Events (RTC0AEN = 1).
Note: When an alarm event occurs and smaRTClock interrupts are enabled, software should clear the
ALRM bit and set the ALARM5-0 registers to the maximum possible value to avoid continuous alarm interrupts.
Internal Register Definition 20.6. CAPTUREn: smaRTClock Timer Capture
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
smaRTClock Addresses: CAPTURE0: 0x00; CAPTURE1: 0x01; CAPTURE2: 0x02; CAPTURE3: 0x03; CAPTURE4: 0x04; CAPTURE5:
0x05
Note: These registers are not SFRs. They can only be accessed indirectly through RTC0ADR and RTC0DAT.
Bits 7–0: CAPTUREn: smaRTClock Set/Capture Value.
These 6 registers (CAPTURE5–CAPTURE0) are used to read or set the 47-bit smaRTClock
timer. Data is transferred to or from the smaRTClock timer when the RTC0SET or RTC0CAP
bits are set.
Note: The LSB of CAPTURE0 is not used. The LSB of the 47-bit smaRTClock timer will appear in
CAPTURE0.1.
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Internal Register Definition 20.7. ALARMn: smaRTClock Alarm
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
11111111
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
smaRTClock Addresses: ALARM0: 0x08; ALARM1: 0x09; ALARM2: 0x0A; ALARM3: 0x0B; ALARM4: 0x0C; ALARM5: 0x0D
Note: These registers are not SFRs. They can only be accessed indirectly through RTC0ADR and RTC0DAT.
Bits 7–0: ALARMn: smaRTClock Alarm Target.
These 6 registers (ALARM5–ALARM0) are used to set an alarm event for the smaRTClock
timer. The smaRTClock alarm should be disabled (RTC0AEN=0) when updating these registers.
Note: The LSB of ALARM0 is not used. The LSB of the 47-bit smaRTClock timer will be compared
against ALARM0.1.
20.4. Backup Regulator and RAM
The smaRTClock includes a backup supply regulator that keeps the smaRTClock peripheral fully functional when VDD is turned off. The backup supply regulator regulates the VRTC-BACKUP supply voltage,
which can range from 1 V to 5.25 V. Switchover logic automatically powers smaRTClock from the backup
supply when the voltage at VRTC-BACKUP is greater than VDD.
The smaRTClock also includes 64 bytes of backup RAM. This memory can be read and written indirectly
using the RAMADDR and RAMDATA internal registers.
Internal Register Definition 20.8. RAMADDR: smaRTClock Backup RAM Address
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
Bit0
smaRTClock
Address:
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Note: This register is not an SFR. It can only be accessed indirectly through RTC0ADR and RTC0DAT.
Bit 7:
0x0E
RAMADDR: smaRTClock Battery Backup RAM Address Bits
These bits select the smaRTClock Backup RAM byte that is targeted by RAMDATA. This
address auto-increments after each read or write of RAMDATA.
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Internal Register Definition 20.9. RAMDATA: smaRTClock Backup RAM 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
Note: This register is not an SFR. It can only be accessed indirectly through RTC0ADR and RTC0DAT.
Bit 7:
smaRTClock
Address:
0x0F
RAMDATA: smaRTClock Battery Backup RAM Data Bits.
These bits provide read and write access to the smaRTClock Backup RAM byte that is
selected by RAMADDR.
Reads and writes of RAMDATA load the value at address RAMADDR into RTC0DAT. The following example writes 0xA5 to address 0x20 in the RAM and reads the value back to a temporary variable:
// in 'C':
unsigned char temp = 0x00;
// Unlock the smaRTClock interface
RTC0KEY = 0xA5;
RTC0KEY = 0xF1;
// Enable the smaRTClock
RTC0ADR = 0x06; // address the RTC0CN register
RTC0DAT = 0x80; // enable the smaRTClock
while ((RTC0ADR & 0x80) == 0x80);
// poll on the BUSY bit
// Write to the smaRTClock RAM
RTC0ADR = 0x0E;// address the RAMADDR register
RTC0DAT = 0x20;// write the address of 0x20 to RAMADDR
while ((RTC0ADR & 0x80) == 0x80);// poll on the BUSY bit
RTC0ADR = 0x0F;// address the RAMDATA register
RTC0DAT = 0xA5;// write 0xA5 to RAM address 0x20
while ((RTC0ADR & 0x80) == 0x80);
// poll on the BUSY bit
// Read from the smaRTClock RAM
RTC0ADR = 0x0E;// address the RAMADDR register
RTC0DAT = 0x20;// write the address of 0x20 to RAMADDR
while ((RTC0ADR & 0x80) == 0x80);
// poll on the BUSY bit
RTC0ADR = 0x0F;
// address the RAMDATA register
RTC0ADR |= 0x80; // initiate a read of the RAMDATA register
while ((RTC0ADR & 0x80) == 0x80);
// poll on the BUSY bit
temp = RTC0DAT; // read the value of RAM address 0x20
; in assembly:
; Unlock the smaRTClock interface
mov RTC0KEY, #0A5h
mov RTC0KEY, #0F1h
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; Enable the smaRTClock
mov RTC0ADR, #06h ; address the RTC0CN register
mov RTC0DAT, #080h ; enable the smaRTClock
L0: mov A, RTC0ADR
; poll on the BUSY bit
jb ACC.7, L0
; Write to the smaRTClock RAM
mov RTC0ADR, #0Eh; address the RAMADDR register
mov RTC0DAT, #20h; write the address of 0x20 to RAMADDR
L1: mov A, RTC0ADR
; poll on the BUSY bit
jb ACC.7, L1
mov RTC0ADR, #0Fh; address the RAMDATA register
mov RTC0DAT, #0A5h; write 0xA5 to RAM address 0x20
L2: mov A, RTC0ADR
; poll on the BUSY bit
jb ACC.7, L2
; Read from the smaRTClock RAM
mov RTC0ADR, #0Eh; address the RAMADDR register
mov RTC0DAT, #20h; write the address of 0x20 to RAMADDR
L3: mov A, RTC0ADR
; poll on the BUSY bit
jb ACC.7, L3
mov RTC0ADR, #0Fh
; address the RAMDATA register
orl RTC0ADR, #80h
; initiate a read of the RAMDATA register
L4: mov A, RTC0ADR
; poll on the BUSY bit
jb ACC.7, L4
movR0, #80h
mov@R0, RTC0DAT
; read the value of RAM address 0x20 into
; the 128-byte internal RAM
To reduce the number of instructions necessary to read and write sections of the 64-byte RAM, the
RAMADDR register automatically increments after each write or read. The following C example initializes
the entire 64-byte RAM to 0xA5 and copies this value from the RAM to an array using the auto-increment
feature:
// in 'C':
unsigned char RAM_data[64] = 0x00;
unsigned char addr;
// Unlock smaRTClock, enable smaRTClock
// Write to the entire smaRTClock RAM
RTC0ADR = 0x0E;// address the RAMADDR register
RTC0DAT = 0x00;// write the address of 0x00 to RAMADDR
while ((RTC0ADR & 0x80) == 0x80);
// poll on the BUSY bit
RTC0ADR = 0x0F;// address the RAMDATA register
for (addr = 0; addr < 64; addr++)
{
RTC0DAT = 0xA5; // write 0xA5 to every RAM address
while ((RTC0ADR & 0x80) == 0x80);// poll on the BUSY bit
}
// Read from the entire smaRTClock RAM
RTC0ADR = 0x0E;// address the RAMADDR register
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RTC0DAT = 0x00;// write the address of 0x00 to RAMADDR
while ((RTC0ADR & 0x80) == 0x80);
// poll on the BUSY bit
RTC0ADR = 0x0F; // address the RAMDATA register
for (addr = 0; addr < 64; addr++)
{
RTC0ADR |= 0x80;
// initiate a read of the RAMDATA register
while ((RTC0ADR & 0x80) == 0x80); // poll on the BUSY bit
RAM_data[addr] = RTC0DAT; // copy the data from the entire RAM
}
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21. SMBus
The SMBus I/O interface is a two-wire, bi-directional serial bus. The SMBus is compliant with the System
Management Bus Specification, version 2, and compatible with the I2C serial bus. Reads and writes to the
interface by the system controller are byte oriented with the SMBus interface autonomously controlling the
serial transfer of the data. Data can be transferred at up to 1/20th of the system clock as a master or slave
(this can be faster than allowed by the SMBus specification, depending on the system clock used). A
method of extending the clock-low duration is available to accommodate devices with different speed
capabilities on the same bus.
The SMBus interface may operate as a master and/or slave, and may function on a bus with multiple masters. The SMBus provides control of SDA (serial data), SCL (serial clock) generation and synchronization,
arbitration logic, and START/STOP control and generation. Three SFRs are associated with the SMBus:
SMB0CF configures the SMBus; SMB0CN controls the status of the SMBus; and SMB0DAT is the data
register, used for both transmitting and receiving SMBus data and slave addresses.
SMB0CN
MT S S A A A S
A X T T CRC I
SMAOK B K
T O
R L
E D
QO
R E
S
T
SMB0CF
E I B E S S S S
N N U XMMMM
S H S T B B B B
M Y H T F CC
B
OOT S S
L E E 1 0
D
00
T0 Overflow
01
T1 Overflow
10
TMR2H Overflow
11
TMR2L Overflow
SMBUS CONTROL LOGIC
Interrupt
Request
Arbitration
SCL Synchronization
SCL Generation (Master Mode)
SDA Control
Data Path
IRQ Generation
Control
SCL
FILTER
SCL
Control
C
R
O
S
S
B
A
R
N
SDA
Control
SMB0DAT
7 6 5 4 3 2 1 0
Port I/O
SDA
FILTER
N
Figure 21.1. SMBus Block Diagram
Rev. 1.1
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C8051F410/1/2/3
21.1. Supporting Documents
It is assumed the reader is familiar with or has access to the following supporting documents:
1. The I2C Manual (AN10216-01), Philips Semiconductor.
2. System Management Bus Specification -- Version 2, SBS Implementers Forum.
21.2. SMBus Configuration
Figure 21.2 shows a typical SMBus configuration. The SMBus specification allows any recessive voltage
between 3.0 V and 5.0 V; different devices on the bus may operate at different voltage levels. The bi-directional SCL (serial clock) and SDA (serial data) lines must be connected to a positive power supply voltage
through a pullup resistor or similar circuit. Every device connected to the bus must have an open-drain or
open-collector output for both the SCL and SDA lines, so that both are pulled high (recessive state) when
the bus is free. The maximum number of devices on the bus is limited only by the requirement that the rise
and fall times on the bus not exceed 300 ns and 1000 ns, respectively.
VSupply = 5 V
VSupply = 3 V
VSupply = 5 V
VSupply = 3 V
Master
Device
Slave
Device 1
Slave
Device 2
SDA
SCL
Figure 21.2. Typical SMBus Configuration
Note: It is recommended that the SDA and SCL pins be configured for high impedance overdrive mode.
See Section “18. Port Input/Output” on page 147 for more information.
21.3. SMBus Operation
Two types of data transfers are possible: data transfers from a master transmitter to an addressed slave
receiver (WRITE), and data transfers from an addressed slave transmitter to a master receiver (READ).
The master device initiates both types of data transfers and provides the serial clock pulses on SCL. The
SMBus interface may operate as a master or a slave, and multiple master devices on the same bus are
supported. If two or more masters attempt to initiate a data transfer simultaneously, an arbitration scheme
is employed with a single master always winning the arbitration. Note that it is not necessary to specify one
device as the Master in a system; any device who transmits a START and a slave address becomes the
master for the duration of that transfer.
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A typical SMBus transaction consists of a START condition followed by an address byte (Bits7-1: 7-bit
slave address; Bit0: R/W direction bit), one or more bytes of data, and a STOP condition. Each byte that is
received (by a master or slave) must be acknowledged (ACK) with a low SDA during a high SCL (see
Figure 21.3). If the receiving device does not ACK, the transmitting device will read a NACK (not acknowledge), which is a high SDA during a high SCL.
The direction bit (R/W) occupies the least-significant bit position of the address byte. The direction bit is set
to logic 1 to indicate a "READ" operation and cleared to logic 0 to indicate a "WRITE" operation.
All transactions are initiated by a master, with one or more addressed slave devices as the target. The
master generates the START condition and then transmits the slave address and direction bit. If the transaction is a WRITE operation from the master to the slave, the master transmits the data a byte at a time
waiting for an ACK from the slave at the end of each byte. For READ operations, the slave transmits the
data waiting for an ACK from the master at the end of each byte. At the end of the data transfer, the master
generates a STOP condition to terminate the transaction and free the bus. Figure 21.3 illustrates a typical
SMBus transaction.
SCL
SDA
SLA6
START
SLA5-0
Slave Address + R/W
R/W
D7
ACK
D6-0
Data Byte
NACK
STOP
Figure 21.3. SMBus Transaction
21.3.1. Arbitration
A master may start a transfer only if the bus is free. The bus is free after a STOP condition or after the SCL
and SDA lines remain high for a specified time (see Section “21.3.4. SCL High (SMBus Free) Timeout”
on page 194). In the event that two or more devices attempt to begin a transfer at the same time, an arbitration scheme is employed to force one master to give up the bus. The master devices continue transmitting until one attempts a HIGH while the other transmits a LOW. Since the bus is open-drain, the bus will
be pulled LOW. The master attempting the HIGH will detect a LOW SDA and lose the arbitration. The winning master continues its transmission without interruption; the losing master becomes a slave and
receives the rest of the transfer if addressed. This arbitration scheme is non-destructive: one device
always wins, and no data is lost.
21.3.2. Clock Low Extension
SMBus provides a clock synchronization mechanism, similar to I2C, which allows devices with different
speed capabilities to coexist on the bus. A clock-low extension is used during a transfer in order to allow
slower slave devices to communicate with faster masters. The slave may temporarily hold the SCL line
LOW to extend the clock low period, effectively decreasing the serial clock frequency.
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21.3.3. SCL Low Timeout
If the SCL line is held low by a slave device on the bus, no further communication is possible. Furthermore,
the master cannot force the SCL line high to correct the error condition. To solve this problem, the SMBus
protocol specifies that devices participating in a transfer must detect any clock cycle held low longer than
25 ms as a “timeout” condition. Devices that have detected the timeout condition must reset the communication no later than 10 ms after detecting the timeout condition.
When the SMBTOE bit in SMB0CF is set, Timer 3 is used to detect SCL low timeouts. Timer 3 is forced to
reload when SCL is high, and allowed to count when SCL is low. With Timer 3 enabled and configured to
overflow after 25 ms (and SMBTOE set), the Timer 3 interrupt service routine can be used to reset (disable
and re-enable) the SMBus in the event of an SCL low timeout.
21.3.4. SCL High (SMBus Free) Timeout
The SMBus specification stipulates that if the SCL and SDA lines remain high for more that 50 µs, the bus
is designated as free. When the SMBFTE bit in SMB0CF is set, the bus will be considered free if SCL and
SDA remain high for more than 10 SMBus clock source periods. If the SMBus is waiting to generate a
Master START, the START will be generated following this timeout. Note that a clock source is required for
free timeout detection, even in a slave-only implementation. Enabling the Bus Free Timeout is recommended.
21.4. Using the SMBus
The SMBus can operate in both Master and Slave modes. The interface provides timing and shifting control for serial transfers; higher level protocol is determined by user software. The SMBus interface provides
the following application-independent features:
•
•
•
•
•
•
•
Byte-wise serial data transfers
Clock signal generation on SCL (Master Mode only) and SDA data synchronization
Timeout/bus error recognition, as defined by the SMB0CF configuration register
START/STOP timing, detection, and generation
Bus arbitration
Interrupt generation
Status information
SMBus interrupts are generated for each data byte or slave address that is transferred. When transmitting,
this interrupt is generated after the ACK cycle so that software may read the received ACK value; when
receiving data, this interrupt is generated before the ACK cycle so that software may define the outgoing
ACK value. See Section “21.5. SMBus Transfer Modes” on page 201 for more details on transmission
sequences.
Interrupts are also generated to indicate the beginning of a transfer when a master (START generated), or
the end of a transfer when a slave (STOP detected). Software should read the SMB0CN (SMBus Control
register) to find the cause of the SMBus interrupt. The SMB0CN register is described in Section
“21.4.2. SMB0CN Control Register” on page 198; Table 21.4 provides a quick SMB0CN decoding reference.
194
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SMBus configuration options include:
•
•
•
•
Timeout detection (SCL Low Timeout and/or Bus Free Timeout)
SDA setup and hold time extensions
Slave event enable/disable
Clock source selection
These options are selected in the SMB0CF register, as described in Section “21.4.1. SMBus Configuration Register” on page 195.
21.4.1. SMBus Configuration Register
The SMBus Configuration register (SMB0CF) is used to enable the SMBus Master and/or Slave modes,
select the SMBus clock source, and select the SMBus timing and timeout options. When the ENSMB bit is
set, the SMBus is enabled for all master and slave events. Slave events may be disabled by setting the
INH bit. With slave events inhibited, the SMBus interface will still monitor the SCL and SDA pins; however,
the interface will NACK all received addresses and will not generate any slave interrupts. When the INH bit
is set, all slave events will be inhibited following the next START (interrupts will continue for the duration of
the current transfer).
Table 21.1. SMBus Clock Source Selection
SMBCS1 SMBCS0
SMBus Clock Source
0
0
Timer 0 Overflow
0
1
Timer 1 Overflow
1
0
Timer 2 High Byte Overflow
1
1
Timer 2 Low Byte Overflow
The SMBCS1-0 bits select the SMBus clock source, which is used only when operating as a master or
when the Bus Free Timeout detection is enabled. When operating as a master, overflows from the selected
source determine the absolute minimum SCL low and high times as defined in Equation 21.1. Note that the
selected clock source may be shared by other peripherals so long as the timer is left running at all times.
For example, Timer 1 overflows may generate the SMBus and UART baud rates simultaneously. Timer
configuration is covered in Section “24. Timers” on page 231.
1
T HighMin = T LowMin = ---------------------------------------------f ClockSourceOverflow
Equation 21.1. Minimum SCL High and Low Times
The selected clock source should be configured to establish the minimum SCL High and Low times as per
Equation 21.1. When the interface is operating as a master (and SCL is not driven or extended by any
other devices on the bus), the typical SMBus bit rate is approximated by Equation 21.2.
f ClockSourceOverflow
BitRate = ---------------------------------------------3
Equation 21.2. Typical SMBus Bit Rate
Rev. 1.1
195
C8051F410/1/2/3
Figure 21.4 shows the typical SCL generation described by Equation 21.2. Notice that THIGH is typically
twice as large as TLOW. The actual SCL output may vary due to other devices on the bus (SCL may be
extended low by slower slave devices, or driven low by contending master devices). The bit rate when
operating as a master will never exceed the limits defined by equation Equation 21.1.
Timer Source
Overflows
SCL
TLow
SCL High Timeout
THigh
Figure 21.4. Typical SMBus SCL Generation
Setting the EXTHOLD bit extends the minimum setup and hold times for the SDA line. The minimum SDA
setup time defines the absolute minimum time that SDA is stable before SCL transitions from low-to-high.
The minimum SDA hold time defines the absolute minimum time that the current SDA value remains stable
after SCL transitions from high-to-low. EXTHOLD should be set so that the minimum setup and hold times
meet the SMBus Specification requirements of 250 ns and 300 ns, respectively. Table 21.2 shows the minimum setup and hold times for the two EXTHOLD settings. Setup and hold time extensions are typically
necessary when SYSCLK is above 10 MHz.
Note: For SCL operation above 100 kHz, EXTHOLD should be cleared to ‘0’.
Table 21.2. Minimum SDA Setup and Hold Times
EXTHOLD
Minimum SDA Setup Time
Minimum SDA Hold Time
Tlow - 4 system clocks
0
3 system clocks
OR
1 system clock + s/w delay*
1
11 system clocks
12 system clocks
*Note: Setup Time for ACK bit transmissions and the MSB of all data transfers. The s/w delay occurs
between the time SMB0DAT or ACK is written and when SI is cleared. Note that if SI is cleared in
the same write that defines the outgoing ACK value, s/w delay is zero.
With the SMBTOE bit set, Timer 3 should be configured to overflow after 25 ms in order to detect SCL low
timeouts (see Section “21.3.3. SCL Low Timeout” on page 194). The SMBus interface will force Timer 3
to reload while SCL is high, and allow Timer 3 to count when SCL is low. The Timer 3 interrupt service routine should be used to reset SMBus communication by disabling and re-enabling the SMBus.
SMBus Free Timeout detection can be enabled by setting the SMBFTE bit. When this bit is set, the bus will
be considered free if SDA and SCL remain high for more than 10 SMBus clock source periods (see
Figure 21.4). When a Free Timeout is detected, the interface will respond as if a STOP was detected (an
interrupt will be generated, and STO will be set). Enabling the Bus Free Timeout is recommended.
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SFR Definition 21.1. SMB0CF: SMBus Clock/Configuration
R/W
R/W
R
ENSMB
INH
BUSY
Bit7
Bit6
Bit5
R/W
R/W
R/W
R/W
EXTHOLD SMBTOE SMBFTE SMBCS1
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
SMBCS0 00000000
Bit0
SFR Address: 0xC1
Bit7:
ENSMB: SMBus Enable.
This bit enables/disables the SMBus interface. When enabled, the interface constantly monitors the SDA and SCL pins.
0: SMBus interface disabled.
1: SMBus interface enabled.
Bit6:
INH: SMBus Slave Inhibit.
When this bit is set to logic 1, the SMBus does not generate an interrupt when slave events
occur. This effectively removes the SMBus slave from the bus. Master Mode interrupts are
not affected.
0: SMBus Slave Mode enabled.
1: SMBus Slave Mode inhibited.
Bit5:
BUSY: SMBus Busy Indicator.
This bit is set to logic 1 by hardware when a transfer is in progress. It is cleared to logic 0
when a STOP or free-timeout is sensed.
Bit4:
EXTHOLD: SMBus Setup and Hold Time Extension Enable.
This bit controls the SDA setup and hold times according to Table 21.2.
0: SDA Extended Setup and Hold Times disabled.
1: SDA Extended Setup and Hold Times enabled.
Bit3:
SMBTOE: SMBus SCL Timeout Detection Enable.
This bit enables SCL low timeout detection. If set to logic 1, the SMBus forces Timer 3 to
reload while SCL is high and allows Timer 3 to count when SCL goes low. Timer 3 should be
programmed to generate interrupts at 25 ms, and the Timer 3 interrupt service routine
should reset SMBus communication.
Bit2:
SMBFTE: SMBus Free Timeout Detection Enable.
When this bit is set to logic 1, the bus will be considered free if SCL and SDA remain high for
more than 10 SMBus clock source periods.
Bits1–0: SMBCS1–SMBCS0: SMBus Clock Source Selection.
These two bits select the SMBus clock source, which is used to generate the SMBus bit
rate. The selected device should be configured according to Equation 21.1.
SMBCS1
0
0
1
1
SMBCS0
0
1
0
1
SMBus Clock Source
Timer 0 Overflow
Timer 1 Overflow
Timer 2 High Byte Overflow
Timer 2 Low Byte Overflow
Rev. 1.1
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C8051F410/1/2/3
21.4.2. SMB0CN Control Register
SMB0CN is used to control the interface and to provide status information (see SFR Definition 21.2). The
higher four bits of SMB0CN (MASTER, TXMODE, STA, and STO) form a status vector that can be used to
jump to service routines. MASTER and TXMODE indicate the master/slave state and transmit/receive
modes, respectively.
STA and STO indicate that a START and/or STOP has been detected or generated since the last SMBus
interrupt. STA and STO are also used to generate START and STOP conditions when operating as a master. Writing a ‘1’ to STA will cause the SMBus interface to enter Master Mode and generate a START when
the bus becomes free (STA is not cleared by hardware after the START is generated). Writing a ‘1’ to STO
while in Master Mode will cause the interface to generate a STOP and end the current transfer after the
next ACK cycle. If STO and STA are both set (while in Master Mode), a STOP followed by a START will be
generated.
As a receiver, writing the ACK bit defines the outgoing ACK value; as a transmitter, reading the ACK bit
indicates the value received on the last ACK cycle. ACKRQ is set each time a byte is received, indicating
that an outgoing ACK value is needed. When ACKRQ is set, software should write the desired outgoing
value to the ACK bit before clearing SI. A NACK will be generated if software does not write the ACK bit
before clearing SI. SDA will reflect the defined ACK value immediately following a write to the ACK bit;
however SCL will remain low until SI is cleared. If a received slave address is not acknowledged, further
slave events will be ignored until the next START is detected.
The ARBLOST bit indicates that the interface has lost an arbitration. This may occur anytime the interface
is transmitting (master or slave). A lost arbitration while operating as a slave indicates a bus error condition. ARBLOST is cleared by hardware each time SI is cleared.
The SI bit (SMBus Interrupt Flag) is set at the beginning and end of each transfer, after each byte frame, or
when an arbitration is lost; see Table 21.3 for more details.
Important Note About the SI Bit: The SMBus interface is stalled while SI is set; thus SCL is held low, and
the bus is stalled until software clears SI.
Table 21.3 lists all sources for hardware changes to the SMB0CN bits. Refer to Table 21.4 for SMBus status decoding using the SMB0CN register.
198
Rev. 1.1
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SFR Definition 21.2. SMB0CN: SMBus Control
R
R
MASTER TXMODE
Bit7
Bit6
R/W
R/W
STA
STO
Bit5
Bit4
R
R
ACKRQ ARBLOST
Bit3
Bit2
R/W
R/W
Reset Value
ACK
SI
00000000
Bit1
Bit0
Bit
Addressable
SFR Address: 0xC0
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
MASTER: SMBus Master/Slave Indicator.
This read-only bit indicates when the SMBus is operating as a master.
0: SMBus operating in Slave Mode.
1: SMBus operating in Master Mode.
TXMODE: SMBus Transmit Mode Indicator.
This read-only bit indicates when the SMBus is operating as a transmitter.
0: SMBus in Receiver Mode.
1: SMBus in Transmitter Mode.
STA: SMBus Start Flag.
Write:
0: No Start generated.
1: When operating as a master, a START condition is transmitted if the bus is free (If the bus
is not free, the START is transmitted after a STOP is received or a timeout is detected). If
STA is set by software as an active Master, a repeated START will be generated after the
next ACK cycle.
Read:
0: No Start or repeated Start detected.
1: Start or repeated Start detected.
STO: SMBus Stop Flag. If set by hardware, this bit must be cleared by software.
Write:
0: No STOP condition is transmitted.
1: Setting STO to logic 1 causes a STOP condition to be transmitted after the next ACK
cycle. When the STOP condition is generated, hardware clears STO to logic 0. If both STA
and STO are set, a STOP condition is transmitted followed by a START condition.
Read:
0: No Stop condition detected.
1: Stop condition detected (if in Slave Mode) or pending (if in Master Mode).
ACKRQ: SMBus Acknowledge Request
This read-only bit is set to logic 1 when the SMBus has received a byte and needs the ACK
bit to be written with the correct ACK response value.
ARBLOST: SMBus Arbitration Lost Indicator.
This read-only bit is set to logic 1 when the SMBus loses arbitration while operating as a
transmitter. A lost arbitration while a slave indicates a bus error condition.
ACK: SMBus Acknowledge Flag.
This bit defines the out-going ACK level and records incoming ACK levels. It should be written each time a byte is received (when ACKRQ=1), or read after each byte is transmitted.
0: A "not acknowledge" has been received (if in Transmitter Mode) OR will be transmitted (if
in Receiver Mode).
1: An "acknowledge" has been received (if in Transmitter Mode) OR will be transmitted (if in
Receiver Mode).
SI: SMBus Interrupt Flag.
This bit is set by hardware under the conditions listed in Table 21.3. SI must be cleared by
software. While SI is set, SCL is held low and the SMBus is stalled.
Rev. 1.1
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Table 21.3. Sources for Hardware Changes to SMB0CN
Bit
Cleared by Hardware When:
• A STOP is generated.
• Arbitration is lost.
• START is generated.
• SMB0DAT is written before the start of an
SMBus frame.
• A START is detected.
• Arbitration is lost.
• SMB0DAT is not written before the
start of an SMBus frame.
STA
• A START followed by an address byte is
received.
• Must be cleared by software.
STO
• A STOP is detected while addressed as a
slave.
• Arbitration is lost due to a detected STOP.
• A pending STOP is generated.
• If STO is set by hardware, it must be
cleared by software.
• A byte has been received and an ACK
response value is needed.
• After each ACK cycle.
MASTER
TXMODE
ACKRQ
ARBLOST
ACK
SI
200
Set by Hardware When:
• A START is generated.
• A repeated START is detected as a MASTER • Each time SI is cleared.
when STA is low (unwanted repeated START).
• SCL is sensed low while attempting to generate a STOP or repeated START condition.
• SDA is sensed low while transmitting a ‘1’
(excluding ACK bits).
• The incoming ACK value is low (ACKNOWLEDGE).
• The incoming ACK value is high (NOT
ACKNOWLEDGE).
• A START has been generated.
• Lost arbitration.
• A byte has been transmitted and an
ACK/NACK received.
• A byte has been received.
• A START or repeated START followed by a
slave address + R/W has been received.
• A STOP has been received.
• Must be cleared by software.
Rev. 1.1
C8051F410/1/2/3
21.4.3. Data Register
The SMBus Data register SMB0DAT holds a byte of serial data to be transmitted or one that has just been
received. Software may safely read or write to the data register when the SI flag is set. Software should not
attempt to access the SMB0DAT register when the SMBus is enabled and the SI flag is cleared to logic 0,
as the interface may be in the process of shifting a byte of data into or out of the register.
Data in SMB0DAT is always shifted out MSB first. After a byte has been received, the first bit of received
data is located at the MSB of SMB0DAT. While data is being shifted out, data on the bus is simultaneously
being shifted in. SMB0DAT always contains the last data byte present on the bus. In the event of lost arbitration, the transition from master transmitter to slave receiver is made with the correct data or address in
SMB0DAT.
SFR Definition 21.3. SMB0DAT: SMBus Data
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: 0xC2
Bits7–0: SMB0DAT: SMBus Data.
The SMB0DAT register contains a byte of data to be transmitted on the SMBus serial interface or a byte that has just been received on the SMBus serial interface. The CPU can read
from or write to this register whenever the SI serial interrupt flag (SMB0CN.0) is set to
logic 1. The serial data in the register remains stable as long as the SI flag is set. When the
SI flag is not set, the system may be in the process of shifting data in/out and the CPU
should not attempt to access this register.
21.5. SMBus Transfer Modes
The SMBus interface may be configured to operate as master and/or slave. At any particular time, it will be
operating in one of the following four modes: Master Transmitter, Master Receiver, Slave Transmitter, or
Slave Receiver. The SMBus interface enters Master Mode any time a START is generated, and remains in
Master Mode until it loses an arbitration or generates a STOP. An SMBus interrupt is generated at the end
of all SMBus byte frames; however, note that the interrupt is generated before the ACK cycle when operating as a receiver, and after the ACK cycle when operating as a transmitter.
21.5.1. Master Transmitter Mode
Serial data is transmitted on SDA while the serial clock is output on SCL. The SMBus interface generates
the START condition and transmits the first byte containing the address of the target slave and the data
direction bit. In this case the data direction bit (R/W) will be logic 0 (WRITE). The master then transmits
one or more bytes of serial data. After each byte is transmitted, an acknowledge bit is generated by the
slave. The transfer is ended when the STO bit is set and a STOP is generated. Note that the interface will
switch to Master Receiver Mode if SMB0DAT is not written following a Master Transmitter interrupt.
Figure 21.5 shows a typical Master Transmitter sequence. Two transmit data bytes are shown, though any
number of bytes may be transmitted. Notice that the ‘data byte transferred’ interrupts occur after the ACK
cycle in this mode.
Rev. 1.1
201
C8051F410/1/2/3
S
SLA
W
Interrupt
A
Data Byte
A
Interrupt
Data Byte
Interrupt
A
P
Interrupt
S = START
P = STOP
A = ACK
W = WRITE
SLA = Slave Address
Received by SMBus
Interface
Transmitted by
SMBus Interface
Figure 21.5. Typical Master Transmitter Sequence
21.5.2. Master Receiver Mode
Serial data is received on SDA while the serial clock is output on SCL. The SMBus interface generates the
START condition and transmits the first byte containing the address of the target slave and the data direction bit. In this case the data direction bit (R/W) will be logic 1 (READ). Serial data is then received from the
slave on SDA while the SMBus outputs the serial clock. The slave transmits one or more bytes of serial
data. After each byte is received, ACKRQ is set to ‘1’ and an interrupt is generated. Software must write
the ACK bit (SMB0CN.1) to define the outgoing acknowledge value (Note: writing a ‘1’ to the ACK bit generates an ACK; writing a ‘0’ generates a NACK). Software should write a ‘0’ to the ACK bit after the last
byte is received, to transmit a NACK. The interface exits Master Receiver Mode after the STO bit is set and
a STOP is generated. Note that the interface will switch to Master Transmitter Mode if SMB0DAT is written
while an active Master Receiver. Figure 21.6 shows a typical Master Receiver sequence. Two received
data bytes are shown, though any number of bytes may be received. Notice that the ‘data byte transferred’
interrupts occur before the ACK cycle in this mode.
S
SLA
R
Interrupt
A
Interrupt
Data Byte
A
Interrupt
Data Byte
N
Interrupt
S = START
P = STOP
A = ACK
N = NACK
R = READ
SLA = Slave Address
Received by SMBus
Interface
Transmitted by
SMBus Interface
Figure 21.6. Typical Master Receiver Sequence
202
Rev. 1.1
P
C8051F410/1/2/3
21.5.3. Slave Receiver Mode
Serial data is received on SDA and the clock is received on SCL. When slave events are enabled (INH =
0), the interface enters Slave Receiver Mode when a START followed by a slave address and direction bit
(WRITE in this case) is received. Upon entering Slave Receiver Mode, an interrupt is generated and the
ACKRQ bit is set. Software responds to the received slave address with an ACK, or ignores the received
slave address with a NACK. If the received slave address is ignored, slave interrupts will be inhibited until
the next START is detected. If the received slave address is acknowledged, zero or more data bytes are
received. Software must write the ACK bit after each received byte to ACK or NACK the received byte. The
interface exits Slave Receiver Mode after receiving a STOP. Note that the interface will switch to Slave
Transmitter Mode if SMB0DAT is written while an active Slave Receiver. Figure 21.7 shows a typical Slave
Receiver sequence. Two received data bytes are shown, though any number of bytes may be received.
Notice that the ‘data byte transferred’ interrupts occur before the ACK cycle in this mode.
Interrupt
S
SLA
W
A
Interrupt
Data Byte
A
Interrupt
Data Byte
A
P
Interrupt
S = START
P = STOP
A = ACK
W = WRITE
SLA = Slave Address
Received by SMBus
Interface
Transmitted by
SMBus Interface
Figure 21.7. Typical Slave Receiver Sequence
Rev. 1.1
203
C8051F410/1/2/3
21.5.4. Slave Transmitter Mode
Serial data is transmitted on SDA and the clock is received on SCL. When slave events are enabled (INH
= 0), the interface enters Slave Receiver Mode (to receive the slave address) when a START followed by a
slave address and direction bit (READ in this case) is received. Upon entering Slave Transmitter Mode, an
interrupt is generated and the ACKRQ bit is set. Software responds to the received slave address with an
ACK, or ignores the received slave address with a NACK. If the received slave address is ignored, slave
interrupts will be inhibited until a START is detected. If the received slave address is acknowledged, data
should be written to SMB0DAT to be transmitted. The interface enters Slave Transmitter Mode, and transmits one or more bytes of data. After each byte is transmitted, the master sends an acknowledge bit; if the
acknowledge bit is an ACK, SMB0DAT should be written with the next data byte. If the acknowledge bit is
a NACK, SMB0DAT should not be written to before SI is cleared (Note: an error condition may be generated if SMB0DAT is written following a received NACK while in Slave Transmitter Mode). The interface
exits Slave Transmitter Mode after receiving a STOP. Note that the interface will switch to Slave Receiver
Mode if SMB0DAT is not written following a Slave Transmitter interrupt. Figure 21.8 shows a typical Slave
Transmitter sequence. Two transmitted data bytes are shown, though any number of bytes may be transmitted. Notice that the ‘data byte transferred’ interrupts occur after the ACK cycle in this mode.
Interrupt
S
SLA
R
A
Interrupt
Data Byte
A
Data Byte
Interrupt
N
P
Interrupt
S = START
P = STOP
N = NACK
R = READ
SLA = Slave Address
Received by SMBus
Interface
Transmitted by
SMBus Interface
Figure 21.8. Typical Slave Transmitter Sequence
21.6. SMBus Status Decoding
The current SMBus status can be easily decoded using the SMB0CN register. In the table below, STATUS
VECTOR refers to the four upper bits of SMB0CN: MASTER, TXMODE, STA, and STO. Note that the
shown response options are only the typical responses; application-specific procedures are allowed as
long as they conform to the SMBus specification. Highlighted responses are allowed but do not conform to
the SMBus specification.
204
Rev. 1.1
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Table 21.4. SMBus Status Decoding
Values
Written
Status
Vector
ACKRQ
ARBLOST
ACK
1110
0
0
X A master START was generated.
0
0
0
1000
1
0
0
1
X
ACK
0
Typical Response Options
STO
1100
Current SMbus State
STA
Master Receiver
Master Transmitter
Mode
Values Read
0
0
X
1
0
X
0
1
X
Load next data byte into
SMB0DAT.
0
0
X
End transfer with STOP.
0
1
X
End transfer with STOP and
start another transfer.
1
1
X
Send repeated START.
1
0
X
Switch to Master Receiver
Mode (clear SI without writing new data to SMB0DAT).
0
0
X
Acknowledge received byte;
Read SMB0DAT.
0
0
1
Send NACK to indicate last
byte, and send STOP.
0
1
0
Send NACK to indicate last
byte, and send STOP followed by START.
1
1
0
Send ACK followed by
repeated START.
1
0
1
1
0
0
Send ACK and switch to
Master Transmitter Mode
(write to SMB0DAT before
clearing SI).
0
0
1
Send NACK and switch to
Master Transmitter Mode
(write to SMB0DAT before
clearing SI).
0
0
0
Load slave address + R/W
into SMB0DAT.
Set STA to restart transfer.
A master data or address byte
was transmitted; NACK received. Abort transfer.
A master data or address byte
was transmitted; ACK received.
A master data byte was received; Send NACK to indicate last
ACK requested.
byte, and send repeated
START.
Rev. 1.1
205
C8051F410/1/2/3
Table 21.4. SMBus Status Decoding (Continued)
Values
Written
ACK
STA
STO
ACK
0101
ARBLOST
Status
Vector
0100
ACKRQ
Slave Transmitter
Mode
Values Read
0
0
0
A slave byte was transmitted;
NACK received.
No action required (expecting STOP condition).
0
0
X
0
0
1
A slave byte was transmitted;
ACK received.
Load SMB0DAT with next
data byte to transmit.
0
0
X
0
1
X
A Slave byte was transmitted;
error detected.
No action required (expecting Master to end transfer).
0
0
X
0
X
An illegal STOP or bus error was
X detected while a Slave Transmis- Clear STO.
sion was in progress.
0
0
X
Acknowledge received
address.
0
0
1
0
A slave address was received;
X
ACK requested.
Do not acknowledge
received address.
0
0
0
Acknowledge received
address.
0
0
1
Do not acknowledge
received address.
0
0
0
Reschedule failed transfer;
do not acknowledge received
address.
1
0
0
0
0
X
1
0
X
0
0
0
0
0
X
0
0
X
1
0
X
Acknowledge received byte;
Read SMB0DAT.
0
0
1
Do not acknowledge
received byte.
0
0
0
0
0
0
1
0
0
1
Current SMbus State
Typical Response Options
0010
Slave Receiver
1
0010
0001
1
Lost arbitration as master; slave
X address received; ACK
requested.
0
1
X
Lost arbitration while attempting a Abort failed transfer.
repeated START.
Reschedule failed transfer.
1
1
X
Lost arbitration while attempting a No action required (transfer
STOP.
complete/aborted).
0
0
A STOP was detected while
X addressed as a Slave Transmitter Clear STO.
or Slave Receiver.
0
1
X
1
0
X
0000
1
206
1
X
Lost arbitration due to a detected Abort transfer.
STOP.
Reschedule failed transfer.
A slave byte was received; ACK
requested.
Lost arbitration while transmitting Abort failed transfer.
a data byte as master.
Reschedule failed transfer.
Rev. 1.1
C8051F410/1/2/3
22. 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 “22.1. Enhanced Baud Rate Generation” on page 208). Received data buffering allows
UART0 to start reception of a second incoming data byte before software has finished reading the previous
data byte.
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
SCON
TI
Serial
Port
Interrupt
MCE
REN
TB8
RB8
TI
RI
SMODE
UART Baud
Rate Generator
Port I/O
RI
Rx IRQ
Rx Clock
Rx Control
Start
Shift
0x1FF
Load
SBUF
RB8
Input Shift Register
(9 bits)
Load SBUF
SBUF
(RX Latch)
Read
SBUF
SFR Bus
RX
Crossbar
Figure 22.1. UART0 Block Diagram
Rev. 1.1
207
C8051F410/1/2/3
22.1. 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 22.2), 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 22.2. UART0 Baud Rate Logic
Timer 1 should be configured for Mode 2, 8-bit auto-reload (see Section “24.1.3. Mode 2: 8-bit
Counter/Timer with Auto-Reload” on page 233). 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 22.1-A and Equation 22.1-B.
A)
1
UartBaudRate = --- × T1_Overflow_Rate
2
B)
T1 CLK
T1_Overflow_Rate = -------------------------256 – TH1
Equation 22.1. 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 “24. Timers”
on page 231. A quick reference for typical baud rates and system clock frequencies is given in Table 22.1
through Table 22.6. Note that the internal oscillator may still generate the system clock when the external
oscillator is driving Timer 1.
208
Rev. 1.1
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22.2. 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 22.3. UART Interconnect Diagram
22.2.1. 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 22.4. 8-Bit UART Timing Diagram
Rev. 1.1
209
C8051F410/1/2/3
22.2.2. 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 22.5. 9-Bit UART Timing Diagram
22.3. 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).
210
Rev. 1.1
C8051F410/1/2/3
Master
Device
Slave
Device
Slave
Device
Slave
Device
V+
RX
TX
RX
TX
RX
TX
RX
TX
Figure 22.6. UART Multi-Processor Mode Interconnect Diagram
Rev. 1.1
211
C8051F410/1/2/3
SFR Definition 22.1. 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:
212
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. 1.1
C8051F410/1/2/3
SFR Definition 22.2. 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. 1.1
213
C8051F410/1/2/3
SYSCLK from
Internal Osc.
Table 22.1. Timer Settings for Standard Baud Rates
Using the Internal Oscillator
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
2400
1200
Frequency: 24.5 MHz
OscillaSCA1-SCA0
Timer 1
Baud Rate
Timer Clock
T1M*
tor Divide
(pre-scale
Reload
% Error
Source
Factor
select)*
Value (hex)
-0.32%
106
SYSCLK
XX
1
0xCB
-0.32%
212
SYSCLK
XX
1
0x96
0.15%
426
SYSCLK
XX
1
0x2B
-0.32%
848
SYSCLK / 4
01
0
0x96
0.15%
1704
SYSCLK / 12
00
0
0xB9
-0.32%
2544
SYSCLK / 12
00
0
0x96
-0.32%
10176
SYSCLK / 48
10
0
0x96
0.15%
20448
SYSCLK / 48
10
0
0x2B
X = Don’t care
*Note: SCA1-SCA0 and T1M bit definitions can be found in Section 24.1.
SYSCLK from SYSCLK from
Internal Osc. External Osc.
Table 22.2. Timer Settings for Standard Baud Rates
Using an External 25.0 MHz Oscillator
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
2400
1200
57600
28800
14400
9600
Baud Rate
% Error
-0.47%
0.45%
-0.01%
0.45%
-0.01%
0.15%
0.45%
-0.01%
-0.47%
-0.47%
0.45%
0.15%
Frequency: 25.0 MHz
OscillaSCA1-SCA0
Timer Clock
tor Divide
(pre-scale
Source
Factor
select)*
108
SYSCLK
XX
218
SYSCLK
XX
434
SYSCLK
XX
872
SYSCLK / 4
01
1736
SYSCLK / 4
01
2608
EXTCLK / 8
11
10464
SYSCLK / 48
10
20832
SYSCLK / 48
10
432
EXTCLK / 8
11
864
EXTCLK / 8
11
1744
EXTCLK / 8
11
2608
EXTCLK / 8
11
1
1
1
0
0
0
0
0
0
0
0
Timer 1
Reload
Value (hex)
0xCA
0x93
0x27
0x93
0x27
0x5D
0x93
0x27
0xE5
0xCA
0x93
0
0x5D
T1M*
X = Don’t care
*Note: SCA1-SCA0 and T1M bit definitions can be found in Section 24.1.
214
Rev. 1.1
C8051F410/1/2/3
SYSCLK from
Internal Osc.
SYSCLK from
External Osc.
Table 22.3. Timer Settings for Standard Baud Rates
Using an External 22.1184 MHz Oscillator
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
2400
1200
230400
115200
57600
28800
14400
9600
Frequency: 22.1184 MHz
OscillaSCA1-SCA0
Timer 1
Baud Rate
Timer Clock
T1M*
tor Divide
(pre-scale
Reload
% Error
Source
Factor
select)*
Value (hex)
0.00%
96
SYSCLK
XX
1
0xD0
0.00%
192
SYSCLK
XX
1
0xA0
0.00%
384
SYSCLK
XX
1
0x40
0.00%
768
SYSCLK / 12
00
0
0xE0
0.00%
1536
SYSCLK / 12
00
0
0xC0
0.00%
2304
SYSCLK / 12
00
0
0xA0
0.00%
9216
SYSCLK / 48
10
0
0xA0
0.00%
18432
SYSCLK / 48
10
0
0x40
0.00%
96
EXTCLK / 8
11
0
0xFA
0.00%
192
EXTCLK / 8
11
0
0xF4
0.00%
384
EXTCLK / 8
11
0
0xE8
0.00%
768
EXTCLK / 8
11
0
0xD0
0.00%
1536
EXTCLK / 8
11
0
0xA0
0.00%
2304
EXTCLK / 8
11
0
0x70
X = Don’t care
*Note: SCA1-SCA0 and T1M bit definitions can be found in Section 24.1.
SYSCLK from
Internal Osc.
SYSCLK from
External Osc.
Table 22.4. Timer Settings for Standard Baud Rates
Using an External 18.432 MHz Oscillator
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
2400
1200
230400
115200
57600
28800
14400
9600
Frequency: 18.432 MHz
OscillaSCA1-SCA0
Timer 1
Baud Rate
Timer Clock
T1M*
tor Divide
(pre-scale
Reload
% Error
Source
Factor
select)*
Value (hex)
0.00%
80
SYSCLK
XX
1
0xD8
0.00%
160
SYSCLK
XX
1
0xB0
0.00%
320
SYSCLK
XX
1
0x60
0.00%
640
SYSCLK / 4
01
0
0xB0
0.00%
1280
SYSCLK / 4
01
0
0x60
0.00%
1920
SYSCLK / 12
00
0
0xB0
0.00%
7680
SYSCLK / 48
10
0
0xB0
0.00%
15360
SYSCLK / 48
10
0
0x60
0.00%
80
EXTCLK / 8
11
0
0xFB
0.00%
160
EXTCLK / 8
11
0
0xF6
0.00%
320
EXTCLK / 8
11
0
0xEC
0.00%
640
EXTCLK / 8
11
0
0xD8
0.00%
1280
EXTCLK / 8
11
0
0xB0
0.00%
1920
EXTCLK / 8
11
0
0x88
X = Don’t care
*Note: SCA1-SCA0 and T1M bit definitions can be found in Section 24.1.
Rev. 1.1
215
C8051F410/1/2/3
SYSCLK from
Internal Osc.
SYSCLK from
External Osc.
Table 22.5. Timer Settings for Standard Baud Rates
Using an External 11.0592 MHz Oscillator
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
2400
1200
230400
115200
57600
28800
14400
9600
Frequency: 11.0592 MHz
OscillaSCA1-SCA0
Timer 1
Baud Rate
Timer Clock
T1M*
tor Divide
(pre-scale
Reload
% Error
Source
Factor
select)*
Value (hex)
0.00%
48
SYSCLK
XX
1
0xE8
0.00%
96
SYSCLK
XX
1
0xD0
0.00%
192
SYSCLK
XX
1
0xA0
0.00%
384
SYSCLK
XX
1
0x40
0.00%
768
SYSCLK / 12
00
0
0xE0
0.00%
1152
SYSCLK / 12
00
0
0xD0
0.00%
4608
SYSCLK / 12
00
0
0x40
0.00%
9216
SYSCLK / 48
10
0
0xA0
0.00%
48
EXTCLK / 8
11
0
0xFD
0.00%
96
EXTCLK / 8
11
0
0xFA
0.00%
192
EXTCLK / 8
11
0
0xF4
0.00%
384
EXTCLK / 8
11
0
0xE8
0.00%
768
EXTCLK / 8
11
0
0xD0
0.00%
1152
EXTCLK / 8
11
0
0xB8
X = Don’t care
*Note: SCA1-SCA0 and T1M bit definitions can be found in Section 24.1.
SYSCLK from
Internal Osc.
SYSCLK from
External Osc.
Table 22.6. Timer Settings for Standard Baud Rates
Using an External 3.6864 MHz Oscillator
216
Target
Baud Rate
(bps)
230400
115200
57600
28800
14400
9600
2400
1200
230400
115200
57600
28800
14400
9600
Frequency: 3.6864 MHz
OscillaSCA1-SCA0
Timer 1
Baud Rate
Timer Clock
T1M*
tor Divide
(pre-scale
Reload
% Error
Source
Factor
select)*
Value (hex)
0.00%
16
SYSCLK
XX
1
0xF8
0.00%
32
SYSCLK
XX
1
0xF0
0.00%
64
SYSCLK
XX
1
0xE0
0.00%
128
SYSCLK
XX
1
0xC0
0.00%
256
SYSCLK
XX
1
0x80
0.00%
384
SYSCLK
XX
1
0x40
0.00%
1536
SYSCLK / 12
00
0
0xC0
0.00%
3072
SYSCLK / 12
00
0
0x80
0.00%
16
EXTCLK / 8
11
0
0xFF
0.00%
32
EXTCLK / 8
11
0
0xFE
0.00%
64
EXTCLK / 8
11
0
0xFC
0.00%
128
EXTCLK / 8
11
0
0xF8
0.00%
256
EXTCLK / 8
11
0
0xF0
0.00%
384
EXTCLK / 8
11
0
0xE8
X = Don’t care
*Note: SCA1-SCA0 and T1M bit definitions can be found in Section 24.1.
Rev. 1.1
C8051F410/1/2/3
23. 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
SPIF
WCOL
MODF
RXOVRN
NSSMD1
NSSMD0
TXBMT
SPIEN
SPI0CFG
SPIBSY
MSTEN
CKPHA
CKPOL
SLVSEL
NSSIN
SRMT
RXBMT
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
7 6 5 4 3 2 1 0
Rx Data
Pin
Control
Logic
Receive Data Buffer
MISO
C
R
O
S
S
B
A
R
Port I/O
NSS
Read
SPI0DAT
Write
SPI0DAT
SFR Bus
Figure 23.1. SPI Block Diagram
Rev. 1.1
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C8051F410/1/2/3
23.1. Signal Descriptions
The four signals used by SPI0 (MOSI, MISO, SCK, NSS) are described below.
23.1.1. 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.
23.1.2. 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.
23.1.3. 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.
23.1.4. 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 23.2, Figure 23.3, and Figure 23.4 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 “18. Port Input/Output” on page 147 for general purpose
port I/O and crossbar information.
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23.2. 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 (SPI0CFG.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 23.2 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 23.3
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 23.4 shows a connection diagram for a master device in
4-wire master mode and two slave devices.
Rev. 1.1
219
C8051F410/1/2/3
Master
Device 1
NSS
GPIO
MISO
MISO
MOSI
MOSI
SCK
SCK
GPIO
NSS
Master
Device 2
Figure 23.2. Multiple-Master Mode Connection Diagram
Master
Device
MISO
MISO
MOSI
MOSI
SCK
SCK
Slave
Device
Figure 23.3. 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 23.4. 4-Wire Single Master and Slave Mode Connection Diagram
23.3. 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.
220
Rev. 1.1
C8051F410/1/2/3
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 23.4 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 23.3 shows a connection diagram between a slave device in 3wire slave mode and a master device.
23.4. 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 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.
23.5. 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 23.5.
The SPI0 Clock Rate Register (SPI0CKR) as shown in SFR Definition 23.3 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,
Rev. 1.1
221
C8051F410/1/2/3
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 23.5. Data/Clock Timing Relationship
23.6. 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.
222
Rev. 1.1
C8051F410/1/2/3
SFR Definition 23.1. 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
Bit 7:
Bit 6:
Bit 5:
Bit 4:
Bit 3:
Bit 2:
Bit 1:
Bit 0:
Bit0
SFR Address: 0xA1
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 23.1 for timing parameters.
Rev. 1.1
223
C8051F410/1/2/3
SFR Definition 23.2. 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
Bit 7:
Bit2
R
R/W
Reset Value
TXBMT
SPIEN
00000110
Bit1
Bit
Addressable
SFR Address: 0xF8
Bit0
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.
Bit 6:
WCOL: Write Collision Flag.
This bit is set to logic 1 by hardware if a write to SPI0DAT is attempted when the transmit
buffer has not been emptied to the SPI shift register. It must be cleared by software.
Bit 5:
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.
Bit 4:
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.
Bits 3–2: NSSMD1–NSSMD0: Slave Select Mode.
Selects between the following NSS operation modes:
(See Section “23.2. SPI0 Master Mode Operation” on page 219 and Section “23.3. SPI0
Slave Mode Operation” on page 220).
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.
Bit 1:
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.
Bit 0:
SPIEN: SPI0 Enable.
This bit enables/disables the SPI.
0: SPI disabled.
1: SPI enabled.
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Rev. 1.1
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SFR Definition 23.3. 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
Bits 7–0: 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. 1.1
225
C8051F410/1/2/3
SFR Definition 23.4. 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
Bits 7–0: 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.
226
Rev. 1.1
C8051F410/1/2/3
SCK*
T
MCKH
T
MCKL
T
MIS
T
MIH
MISO
MOSI
* SCK is shown for CKPOL = 0. SCK is the opposite polarity for CKPOL = 1.
Figure 23.6. 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 23.7. SPI Master Timing (CKPHA = 1)
Rev. 1.1
227
C8051F410/1/2/3
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 23.8. 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 23.9. SPI Slave Timing (CKPHA = 1)
228
Rev. 1.1
C8051F410/1/2/3
Table 23.1. SPI Slave Timing Parameters
Parameter
Description
Min
Max
Units
Master Mode Timing* (See Figure 23.6 and Figure 23.7)
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 23.8 and Figure 23.9)
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.
Rev. 1.1
229
C8051F410/1/2/3
NOTES:
230
Rev. 1.1
C8051F410/1/2/3
24. Timers
Each MCU includes four counter/timers: two are 16-bit counter/timers compatible with those found in the
standard 8051, and two are 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 and Timer 3 offer 16-bit and split 8-bit timer functionality with auto-reload. Timer 2 and
Timer 3 also have a smaRTClock Capture Mode that can be used to measure the smaRTClock clock with
respect to another oscillator.
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:
Timer 3 Modes:
16-bit timer with auto-reload
16-bit timer with auto-reload
Two 8-bit timers 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 (T1MT0M) 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 24.3 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 and
Timer 3 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.
24.1. 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 “12.4. Interrupt Register Descriptions” on page 112); Timer 1 interrupts can be enabled by
setting the ET1 bit in the IE register (Section 12.4). 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.
24.1.1. 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. 1.1
231
C8051F410/1/2/3
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
“18.1. Priority Crossbar Decoder” on page 149 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 24.3).
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 12.7. “IT01CF: INT0/INT1
Configuration” on page 118). Setting GATE0 to ‘1’ allows the timer to be controlled by the external input
signal /INT0 (see Section “12.4. Interrupt Register Descriptions” on page 112), 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 12.7. “IT01CF: INT0/INT1 Configuration” on page 118).
IT01CF
Figure 24.1. T0 Mode 0 Block Diagram
232
Rev. 1.1
C8051F410/1/2/3
24.1.2. 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.
24.1.3. 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 “12.5. External Interrupts” on page 117
for details on the external input signals /INT0 and /INT1).
IT01CF
Figure 24.2. T0 Mode 2 Block Diagram
Rev. 1.1
233
C8051F410/1/2/3
24.1.4. 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
SYSCLK
TH0
(8 bits)
1
TCON
0
1
T0
TL0
(8 bits)
TR0
Crossbar
/INT0
GATE0
IN0PL
XOR
Figure 24.3. T0 Mode 3 Block Diagram
234
Rev. 1.1
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
Interrupt
Interrupt
C8051F410/1/2/3
SFR Definition 24.1. 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 12.7. “IT01CF: INT0/INT1 Configuration” on page 118).
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 12.7. “IT01CF: INT0/INT1 Configuration” on page 118).
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 12.7. “IT01CF: INT0/INT1 Configuration” on page 118).
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 12.7. “IT01CF: INT0/INT1 Configuration” on page 118).
0: /INT0 is level triggered.
1: /INT0 is edge triggered.
Rev. 1.1
235
C8051F410/1/2/3
SFR Definition 24.2. 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 12.7. “IT01CF: INT0/INT1 Configuration” on page 118).
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 12.7. “IT01CF: INT0/INT1 Configuration” on page 118).
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
236
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. 1.1
C8051F410/1/2/3
SFR Definition 24.3. CKCON: Clock Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
T3MH
T3ML
T2MH
T2ML
T1M
T0M
SCA1
SCA0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x8E
Bit7:
T3MH: Timer 3 High Byte Clock Select.
This bit selects the clock supplied to the Timer 3 high byte if Timer 3 is configured in split 8bit timer mode. T3MH is ignored if Timer 3 is in any other mode.
0: Timer 3 high byte uses the clock defined by the T3XCLK bit in TMR3CN.
1: Timer 3 high byte uses the system clock.
Bit6:
T3ML: Timer 3 Low Byte Clock Select.
This bit selects the clock supplied to Timer 3. If Timer 3 is configured in split 8-bit timer
mode, this bit selects the clock supplied to the lower 8-bit timer.
0: Timer 3 low byte uses the clock defined by the T3XCLK bit in TMR3CN.
1: Timer 3 low byte uses the system clock.
Bit5:
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. 1.1
237
C8051F410/1/2/3
SFR Definition 24.4. 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 24.5. 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 24.6. 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 24.7. 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.
238
Rev. 1.1
C8051F410/1/2/3
24.2. 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 smaRTClock 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.
24.2.1. 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 24.4,
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
TR2
External Clock / 8
SYSCLK
1
TCLK
TMR2L
TMR2H
TMR2CN
SYSCLK / 12
1
TF2H
TF2L
TF2LEN
Interrupt
T2SPLIT
TR2
T2XCLK
TMR2RLL TMR2RLH
Reload
Figure 24.4. Timer 2 16-Bit Mode Block Diagram
Rev. 1.1
239
C8051F410/1/2/3
24.2.2. 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 24.5. 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 24.5. Timer 2 8-Bit Mode Block Diagram
240
Rev. 1.1
Interrupt
C8051F410/1/2/3
24.2.3. External/smaRTClock Capture Mode
Capture Mode allows either the external oscillator or the smaRTClock clock to be measured against the
system clock. The external oscillator and smaRTClock 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, or the smaRTClock clock divided by 8, depending on the T2ML (CKCON.4), T2XCLK, and
T2RCLK settings. The timer will capture either every 8 external clock cycles or every 8 smaRTClock 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 or
smaRTClock clock 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.
For example, if T2ML = 1b, T2RCLK = 0b, and TF2CEN = 1b, Timer 2 will clock every SYSCLK and capture every smaRTClock clock divided by 8. If the SYSCLK is 24.5 MHz and the difference between two
successive captures is 5984, then the smaRTClock clock is:
24.5 MHz / (5984 / 8) = 0.032754 MHz or 32.754 kHz.
This mode allows software to determine the exact smaRTClock frequency in self-oscillate mode and the
external oscillator frequency when an RC network or capacitor is used to generate the signal.
CKCON
T T T T T T S
3 3 2 2 1 0 C
MMMMMM A
H L H L
1
T2RCLK
S
C
A
0
T2XCLK
1
SYSCLK
1
1
External Osc. / 8
TCLK
TR2
0
0
SYSCLK / 12
TMR2H
TMR2L
Capture
0
T2RCLK
TMR2RLH TMR2RLL
External Osc. / 8
1
smaRTClock / 8
0
TMR2CN
smaRTClock / 8
TF2H
TF2L
TF2LEN
TF2CEN
Interrupt
TR2
T2RCLK
T2XCLK
TF2CEN
Figure 24.6. Timer 2 Capture Mode Block Diagram
Rev. 1.1
241
C8051F410/1/2/3
SFR Definition 24.8. 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:
242
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 smaRTClock 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
smaRTClock 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. 1.1
C8051F410/1/2/3
SFR Definition 24.9. 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
Bits 7–0: TMR2RLL: Timer 2 Reload Register Low Byte.
TMR2RLL holds the low byte of the reload value for Timer 2.
SFR Definition 24.10. 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
Bits 7–0: TMR2RLH: Timer 2 Reload Register High Byte.
The TMR2RLH holds the high byte of the reload value for Timer 2.
SFR Definition 24.11. 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
Bits 7–0: 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 24.12. 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
Bits 7–0: 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. 1.1
243
C8051F410/1/2/3
24.3. Timer 3
Timer 3 is a 16-bit timer formed by two 8-bit SFRs: TMR3L (low byte) and TMR3H (high byte). Timer 3 may
operate in 16-bit auto-reload mode or (split) 8-bit auto-reload mode. The T3SPLIT bit (TMR3CN.3) defines
the Timer 3 operation mode. Timer 3 can also be used in Capture Mode to measure the smaRTClock clock
frequency or the External Oscillator clock frequency.
Timer 3 may be clocked by the system clock, the system clock divided by 12, or the external oscillator
source divided by 8. Note that the external oscillator source divided by 8 is synchronized with the system
clock.
24.3.1. 16-bit Timer with Auto-Reload
When T3SPLIT (TMR3CN.3) is zero, Timer 3 operates as a 16-bit timer with auto-reload. Timer 3 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 3
reload registers (TMR3RLH and TM3RLL) is loaded into the Timer 3 register as shown in Figure 24.7, and
the Timer 3 High Byte Overflow Flag (TMR3CN.7) is set. If Timer 3 interrupts are enabled, an interrupt will
be generated on each Timer 3 overflow. Additionally, if Timer 3 interrupts are enabled and the TF3LEN bit
is set (TMR3CN.5), an interrupt will be generated each time the lower 8 bits (TMR3L) overflow from 0xFF
to 0x00.
CKCON
T3XCLK
SYSCLK / 12
T T T T T T S
3 3 2 2 1 0C
MMMMMMA
H LH L
1
S
C
A
0
0
0
SYSCLK
1
TCLK
TMR3L
TMR3H
TMR3CN
TR3
External Clock / 8
1
TF3H
TF3L
TF3LEN
T3SPLIT
TR3
T3XCLK
TMR3RLL TMR3RLH
Reload
Figure 24.7. Timer 3 16-Bit Mode Block Diagram
244
Rev. 1.1
Interrupt
C8051F410/1/2/3
24.3.2. 8-bit Timers with Auto-Reload
When T3SPLIT is set, Timer 3 operates as two 8-bit timers (TMR3H and TMR3L). Both 8-bit timers operate in auto-reload mode as shown in Figure 24.8. TMR3RLL holds the reload value for TMR3L; TMR3RLH
holds the reload value for TMR3H. The TR3 bit in TMR3CN handles the run control for TMR3H. TMR3L 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 3 Clock Select bits (T3MH and T3ML in CKCON) select either SYSCLK or
the clock defined by the Timer 3 External Clock Select bit (T3XCLK in TMR3CN), as follows:
T3MH
0
0
1
T3XCLK TMR3H Clock Source
0
SYSCLK / 12
1
External Clock / 8
X
SYSCLK
T3ML
0
0
1
T3XCLK
0
1
X
TMR3L Clock Source
SYSCLK / 12
External Clock / 8
SYSCLK
The TF3H bit is set when TMR3H overflows from 0xFF to 0x00; the TF3L bit is set when TMR3L overflows
from 0xFF to 0x00. When Timer 3 interrupts are enabled, an interrupt is generated each time TMR3H overflows. If Timer 3 interrupts are enabled and TF3LEN (TMR3CN.5) is set, an interrupt is generated each
time either TMR3L or TMR3H overflows. When TF3LEN is enabled, software must check the TF3H and
TF3L flags to determine the source of the Timer 3 interrupt. The TF3H and TF3L 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
T3XCLK
SYSCLK / 12
0
External Clock / 8
1
S
C
A
0
TMR3RLH
Reload
0
TCLK
TR3
TMR3H
TMR3RLL
SYSCLK
Reload
TMR3CN
1
TF3H
TF3L
TF3LEN
TF3CEN
T3SPLIT
TR3
Interrupt
T3XCLK
1
TCLK
TMR3L
To ADC
0
Figure 24.8. Timer 3 8-Bit Mode Block Diagram
Rev. 1.1
245
C8051F410/1/2/3
24.3.3. External/smaRTClock Capture Mode
Capture Mode allows either the external oscillator or the smaRTClock clock to be measured against the
system clock. The external oscillator and smaRTClock clock can also be compared against each other.
Timer 3 can be clocked from the system clock, the system clock divided by 12, the external oscillator
divided by 8, or the smaRTClock clock divided by 8, depending on the T3ML (CKCON.6), T3XCLK, and
T3RCLK settings. The timer will capture either every 8 external clock cycles or every 8 smaRTClock clock
cycles, depending on the T3RCLK setting. When a capture event is generated, the contents of Timer 3
(TMR3H:TMR3L) are loaded into the Timer 3 reload registers (TMR3RLH:TMR3RLL) and the TF3H flag is
set. By recording the difference between two successive timer capture values, the external oscillator or
smaRTClock clock can be determined with respect to the Timer 3 clock. The Timer 3 clock should be much
faster than the capture clock to achieve an accurate reading. Timer 3 should be in 16-bit auto-reload mode
when using Capture Mode.
For example, if T3ML = 1b, T3RCLK = 0b, and TF3CEN = 1b, Timer 3 will clock every SYSCLK and capture every smaRTClock clock divided by 8. If the SYSCLK is 24.5 MHz and the difference between two
successive captures is 5984, then the smaRTClock clock is:
24.5 MHz / (5984 / 8) = 0.032754 MHz or 32.754 kHz.
This mode allows software to determine the exact smaRTClock frequency in self-oscillate mode and the
external oscillator frequency when an RC network or capacitor is used to generate the signal.
CKCON
T T T T T T S
3 3 2 2 1 0 C
MMMMMMA
H L H L
1
T3RCLK
S
C
A
0
T3XCLK
1
SYSCLK
1
1
External Osc. / 8
TCLK
TR3
0
0
SYSCLK / 12
TMR3H
TMR3L
Capture
0
T3RCLK
TMR3RLH TMR3RLL
External Osc. / 8
1
smaRTClock / 8
0
TMR3CN
smaRTClock / 8
TF3H
TF3L
TF3LEN
TF3CEN
TR3
T3RCLK
T3XCLK
TF3CEN
Figure 24.9. Timer 3 Capture Mode Block Diagram
246
Rev. 1.1
Interrupt
C8051F410/1/2/3
SFR Definition 24.13. TMR3CN: Timer 3 Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
TF3H
TF3L
TF3LEN
TF3CEN
T3SPLIT
TR3
T3RCLK
T3XCLK
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address: 0x91
Bit7:
Bit6:
Bit5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
TF3H: Timer 3 High Byte Overflow Flag.
Set by hardware when the Timer 3 high byte overflows from 0xFF to 0x00. In 16 bit mode,
this will occur when Timer 3 overflows from 0xFFFF to 0x0000. When the Timer 3 interrupt is
enabled, setting this bit causes the CPU to vector to the Timer 3 interrupt service routine.
TF3H is not automatically cleared by hardware and must be cleared by software.
TF3L: Timer 3 Low Byte Overflow Flag.
Set by hardware when the Timer 3 low byte overflows from 0xFF to 0x00. When this bit is
set, an interrupt will be generated if TF3LEN is set and Timer 3 interrupts are enabled. TF3L
will set when the low byte overflows regardless of the Timer 3 mode. This bit is not automatically cleared by hardware.
TF3LEN: Timer 3 Low Byte Interrupt Enable.
This bit enables/disables Timer 3 Low Byte interrupts. If TF3LEN is set and Timer 3 interrupts are enabled, an interrupt will be generated when the low byte of Timer 3 overflows.
This bit should be cleared when operating Timer 3 in 16-bit mode.
0: Timer 3 Low Byte interrupts disabled.
1: Timer 3 Low Byte interrupts enabled.
TF3CEN: Timer 3 Capture Enable.
0: Timer 3 capture mode disabled.
1: Timer 3 capture mode enabled.
T3SPLIT: Timer 3 Split Mode Enable.
When this bit is set, Timer 3 operates as two 8-bit timers with auto-reload.
0: Timer 3 operates in 16-bit auto-reload mode.
1: Timer 3 operates as two 8-bit auto-reload timers.
TR3: Timer 3 Run Control.
This bit enables/disables Timer 3. In 8-bit mode, this bit enables/disables TMR3H only;
TMR3L is always enabled in this mode.
0: Timer 3 disabled.
1: Timer 3 enabled.
T3RCLK: Timer 3 Capture Mode.
This bit controls the Timer 3 capture source when TF3CEN=1. If T3XCLK = 1 and T3ML
(CKCON.6) = 0, this bit also controls the clock source for Timer 3.
0: Capture every smaRTClock clock/8. If T3XCLK = 1 and T3ML (CKCON.6) = 0, count at
external oscillator/8.
1: Capture every external oscillator/8. If T3XCLK = 1 and T3ML (CKCON.6) = 0, count at
smaRTClock clock/8.
T3XCLK: Timer 3 External Clock Select.
This bit selects the external clock source for Timer 3. If Timer 3 is in 8-bit mode, this bit
selects the external oscillator clock source for both timer bytes. However, the Timer 3 Clock
Select bits (T3MH and T3ML in register CKCON) may still be used to select between the
external clock and the system clock for either timer.
0: Timer 3 external clock selection is the system clock divided by 12.
1: Timer 3 external clock uses the clock defined by the T3RCLK bit.
Rev. 1.1
247
C8051F410/1/2/3
SFR Definition 24.14. TMR3RLL: Timer 3 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: 0x92
Bits 7-0: TMR3RLL: Timer 3 Reload Register Low Byte.
TMR3RLL holds the low byte of the reload value for Timer 3.
SFR Definition 24.15. TMR3RLH: Timer 3 Reload Register 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: 0x93
Bits 7-0: TMR3RLH: Timer 3 Reload Register High Byte.
The TMR3RLH holds the high byte of the reload value for Timer 3.
SFR Definition 24.16. TMR3L: Timer 3 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: 0x94
Bits 7-0: TMR3L: Timer 3 Low Byte.
In 16-bit mode, the TMR3L register contains the low byte of the 16-bit Timer 3. In 8-bit mode,
TMR3L contains the 8-bit low byte timer value.
SFR Definition 24.17. TMR3H Timer 3 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: 0x95
Bits 7-0: TMR3H: Timer 3 High Byte.
In 16-bit mode, the TMR3H register contains the high byte of the 16-bit Timer 3. In 8-bit
mode, TMR3H contains the 8-bit high byte timer value.
248
Rev. 1.1
C8051F410/1/2/3
25. 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 six 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 “18.1. Priority
Crossbar Decoder” on page 149 for details on configuring the Crossbar). The counter/timer is driven by
a programmable timebase that can select between seven sources: system clock, system clock divided by
four, system clock divided by twelve, the external oscillator clock source divided by 8, smaRTClock Clock
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 six modes: Edge-Triggered Capture, Software Timer, High-Speed Output, Frequency Output, 8-Bit PWM, or 16-Bit PWM (each mode is described in
Section “25.2. Capture/Compare Modules” on page 251). The PCA is configured and controlled
through the system controller's Special Function Registers. The PCA block diagram is shown in
Figure 25.1
Important Note: The PCA Module 5 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 25.3 for details.
SYSCLK/12
SYSCLK/4
Timer 0 Overflow
ECI
SYSCLK
PCA
CLOCK
MUX
16-Bit Counter/Timer
External Clock/8
smaRTClock/8
Capture/Compare
Module 0
Capture/Compare
Module 1
Capture/Compare
Module 2
Capture/Compare
Module 3
Capture/Compare
Module 4
Capture/Compare
Module 5
CEX5
CEX4
CEX3
CEX2
CEX1
CEX0
ECI
Crossbar
Port I/O
Figure 25.1. PCA Block Diagram
Rev. 1.1
249
C8051F410/1/2/3
25.1. 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 25.1.
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 25.1. 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*
smaRTClock clock divided by 8*
*Note: External clock divided by 8 and smaRTClock 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
CCC
FRC
F
5
C
C
F
4
C
C
F
3
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
RTC0 Clock/8
000
001
010
0
011
1
PCA0H
PCA0L
Overflow
CF
100
101
To PCA Modules
110
Figure 25.2. PCA Counter/Timer Block Diagram
250
To PCA Interrupt System
Rev. 1.1
C8051F410/1/2/3
25.2. 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 25.2 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 25.3 for details on the PCA interrupt configuration.
Table 25.2. 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
X
1
X
1
X
1
0
1
1
1
X = Don’t Care
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
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 EC
WCA
MOP
1 MP
6 n n
n
C
A
P
N
n
MT P
AOW
TGM
n n n
PCA0CN
E
C
C
F
n
CCC
F RC
F
5
C
C
F
4
C
C
F
3
C
C
F
2
C
C
F
1
PCA0MD
C
C
F
0
C
I
D
L
C
P
S
2
C
P
S
1
CE
PC
S F
0
0
PCA Counter/
Timer Overflow
1
ECCF0
EPCA0
(EIE1.4)
0
PCA Module 0
(CCF0)
1
EA
(IE.7)
0
0
1
1
Interrupt
Priority
Decoder
ECCF1
0
PCA Module 1
(CCF1)
1
ECCF2
0
PCA Module 2
(CCF2)
1
ECCF3
0
PCA Module 3
(CCF3)
1
ECCF4
0
PCA Module 4
(CCF4)
1
ECCF5
PCA Module 5
(CCF5)
0
1
Figure 25.3. PCA Interrupt Block Diagram
Rev. 1.1
251
C8051F410/1/2/3
25.2.1. 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
CCCCCCCC
FRCCCCCC
FFFFFF
5 4 3 2 1 0
(to CCFn)
P E CCMT P E
WC A A AOWC
MOPP TGMC
1 MPN n n n F
6 n n n
n
n
1
PCA0CPLn
PCA0CPHn
Capture
0
1
PCA
Timebase
PCA0L
PCA0H
Figure 25.4. 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.
252
Rev. 1.1
C8051F410/1/2/3
25.2.2. 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
CCCCCCCC
FRCCCCCC
FFFFFF
5 4 3 2 1 0
PCA0CPHn
0 0 x
Enable
16-bit Comparator
PCA
Timebase
PCA0L
Match
0
1
PCA0H
Figure 25.5. PCA Software Timer Mode Diagram
Rev. 1.1
253
C8051F410/1/2/3
25.2.3. 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 A OWC
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
CCCC
FRCC
F F
5 4
PCA0CPHn
16-bit Comparator
Match
C
C
F
3
CC
CC
F F
2 1
C
C
F
0
0
1
TOGn
Toggle
PCA
Timebase
0 CEXn
1
PCA0L
Crossbar
Port I/O
PCA0H
Figure 25.6. 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.
254
Rev. 1.1
C8051F410/1/2/3
25.2.4. 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 25.1.
F PCA
F CEXn = ----------------------------------------2 × PCA0CPHn
Note: A value of 0x00 in the PCA0CPHn register is equal to 256 for this equation.
Equation 25.1. 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
PCA0CPHn
Adder
Enable
TOGn
Toggle
0
Enable
PCA Timebase
8-bit
Comparator
match
0 CEXn
1
Crossbar
Port I/O
PCA0L
Figure 25.7. PCA Frequency Output Mode
Rev. 1.1
255
C8051F410/1/2/3
25.2.5. 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 25.8). 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 25.2.
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 25.2. 8-Bit PWM Duty Cycle
Using Equation 25.2, 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
SET
CLR
Q
CEXn
Crossbar
Q
PCA0L
Overflow
Figure 25.8. PCA 8-Bit PWM Mode Diagram
256
Rev. 1.1
Port I/O
C8051F410/1/2/3
25.2.6. 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 25.3.
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 25.3. 16-Bit PWM Duty Cycle
Using Equation 25.3, 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
16-bit Comparator
match
S
R
PCA Timebase
PCA0H
SET
CLR
Q
CEXn
Crossbar
Port I/O
Q
PCA0L
Overflow
Figure 25.9. PCA 16-Bit PWM Mode
25.3. Watchdog Timer Mode
A programmable watchdog timer (WDT) function is available through the PCA Module 5. The WDT is used
to generate a reset if the time between writes to the WDT update register (PCA0CPH5) 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 5 operates as a watchdog timer (WDT). The
Module 5 high byte is compared to the PCA counter high byte; the Module 5 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. 1.1
257
C8051F410/1/2/3
25.3.1. 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 5 is forced into software timer mode.
Writes to the Module 5 mode register (PCA0CPM5) 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 PCA0CPH5 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 PCA0CPH5. Upon a PCA0CPH5 write, PCA0H plus the offset held in PCA0CPL5 is loaded
into PCA0CPH5 (See Figure 25.10).
PCA0MD
CWW
I D D
DT L
L E C
K
CCCE
PPPC
SSSF
2 1 0
PCA0CPH5
Enable
PCA0CPL5
Write to
PCA0CPH5
8-bit Adder
8-bit
Comparator
PCA0H
Match
Reset
PCA0L Overflow
Adder
Enable
Figure 25.10. PCA Module 5 with Watchdog Timer Enabled
258
Rev. 1.1
C8051F410/1/2/3
Note that the 8-bit offset held in PCA0CPH5 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 25.4, where PCA0L is the value of the PCA0L register
at the time of the update.
Offset = ( 256 × PCA0CPL5 ) + ( 256 – PCA0L )
Equation 25.4. Watchdog Timer Offset in PCA Clocks
The WDT reset is generated when PCA0L overflows while there is a match between PCA0CPH5 and
PCA0H. Software may force a WDT reset by writing a ‘1’ to the CCF5 flag (PCA0CN.5) while the WDT is
enabled.
25.3.2. 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 PCA0CPL5 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 PCA0CPL5 defaults to 0x00. Using Equation 25.4, this results in a WDT
timeout interval of 3072 system clock cycles. Table 25.3 lists some example timeout intervals for typical
system clocks.
Rev. 1.1
259
C8051F410/1/2/3
Table 25.3. 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
PCA0CPL5
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
191,4062
32
255
128
32
530
24576
12384
3168
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.
260
Rev. 1.1
C8051F410/1/2/3
25.4. Register Descriptions for PCA
Following are detailed descriptions of the special function registers related to the operation of the PCA.
SFR Definition 25.1. PCA0CN: PCA Control
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
CF
CR
CCF5
CCF4
CCF3
CCF2
CCF1
CCF0
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit7:
Bit6:
Bit0:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
Bit
Addressable
SFR Address: 0xD8
Bit0
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.
CR: PCA Counter/Timer Run Control.
This bit enables/disables the PCA Counter/Timer.
0: PCA Counter/Timer disabled.
1: PCA Counter/Timer enabled.
CCF5: PCA Module 5 Capture/Compare Flag.
This bit is set by hardware when a match or capture occurs. When the CCF5 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.
CCF4: PCA Module 4 Capture/Compare Flag.
This bit is set by hardware when a match or capture occurs. When the CCF4 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.
CCF3: PCA Module 3 Capture/Compare Flag.
This bit is set by hardware when a match or capture occurs. When the CCF3 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.
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.
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.
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.
Rev. 1.1
261
C8051F410/1/2/3
SFR Definition 25.2. PCA0MD: PCA Mode
R/W
R/W
R/W
R
R/W
R/W
R/W
R/W
Reset Value
CIDL
WDTE
Bit7
Bit6
WDLCK
-
CPS2
CPS1
CPS0
ECF
01000000
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
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 5 is used as the watchdog timer.
0: Watchdog Timer disabled.
1: PCA Module 5 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*
smaRTClock clock divided by 8*
Reserved
*Note: External clock divided by 8 and smaRTClock 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.
262
Rev. 1.1
C8051F410/1/2/3
SFR Definition 25.3. 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
PCA0CPM0: 0xDA, PCA0CPM1: 0xDB, PCA0CPM2: 0xDC, PCA0CPM3: 0xDD, PCA0CPM4: 0xDE,
SFR Address:
PCA0CPM5: 0xCE
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.
Rev. 1.1
263
C8051F410/1/2/3
SFR Definition 25.4. PCA0L: PCA Counter/Timer Low Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
R/W
Reset Value
00000000
Bit0
SFR Address: 0xF9
Bits 7–0: PCA0L: PCA Counter/Timer Low Byte.
The PCA0L register holds the low byte (LSB) of the 16-bit PCA Counter/Timer.
SFR Definition 25.5. 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
Bits 7–0: PCA0H: PCA Counter/Timer High Byte.
The PCA0H register holds the high byte (MSB) of the 16-bit PCA Counter/Timer.
SFR Definition 25.6. 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
PCA0CPL0: 0xFB, PCA0CPL1: 0xE9, PCA0CPL2: 0xEB, PCA0CPL3: 0xED, PCA0CPL4: 0xFD, PCA0CPL5:
SFR Address:
0xD2
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 25.7. PCA0CPHn: PCA Capture Module 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
PCA0CPH0: 0xFC, PCA0CPH1: 0xEA, PCA0CPH2: 0xEC, PCA0CPH3: 0xEE, PCA0CPH4: 0xFE, PCA0CPH5:
SFR Address:
0xD3
Bits7–0: PCA0CPHn: PCA Capture Module High Byte.
The PCA0CPHn register holds the high byte (MSB) of the 16-bit capture module n.
264
Rev. 1.1
C8051F410/1/2/3
26. C2 Interface
C8051F41x 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.
26.1. 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 26.1. C2ADD: C2 Address
Reset Value
00000000
Bit7
Bits7-0:
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
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 26.2. DEVICEID: C2 Device ID
Reset Value
00001011
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
This read-only register returns the 8-bit device ID: 0x0C (C8051F41x).
Rev. 1.1
265
C8051F410/1/2/3
C2 Register Definition 26.3. REVID: C2 Revision ID
Reset Value
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
This read-only register returns the 8-bit revision ID: 0x00 (Revision A).
C2 Register Definition 26.4. FPCTL: C2 Flash Programming Control
Reset Value
00000000
Bit7
Bits7-0
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
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 26.5. FPDAT: C2 Flash Programming Data
Reset Value
00000000
Bit7
Bits7-0:
Bit6
Bit4
Bit3
Bit2
Bit1
Bit0
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
266
Bit5
Command
Flash Block Read
Flash Block Write
Flash Page Erase
Device Erase
Rev. 1.1
C8051F410/1/2/3
26.2. 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 (P2.0) 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 26.1.
C8051Fxxx
/Reset (a)
C2CK
Input (b)
C2D
Output (c)
C2 Interface Master
Figure 26.1. Typical C2 Pin Sharing
The configuration in Figure 26.1 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. 1.1
267
C8051F410/1/2/3
DOCUMENT CHANGE LIST
Revision 0.7 to Revision 0.8
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Updated specification tables with most recently available characterization data.
Corrected references to configuring pins for Analog Mode - Port Latch must contain a '1'.
SFR Definition 5.6: Address correction to 0xBA.
Added Figure 8.2 showing power connection diagram without using on-chip regulator.
Section 9 : Removed references to "High Speed Analog Mode".
Table 11.2 : Corrected SFR Name P2MDIN on location 0xF3.
Section 14 : Corrected operational description of CRC engine.
Section 18, Important Note on page 151 : Added "and have the same behavior as P0 in Normal Mode." to
last sentence.
Section 19.2.2 : Inserted Step 3 "Release the crystal pins by writing ‘1's to the port latch."
Section 19.3 : Added Figure 19.3 and text to describe behavior of clock multiplier with slower input frequencies.
Section 21: Corrected SMBus maximum rate to 1/20th system clock.
Table 21.4 : Made corrections to SMBus state descriptions.
Figure 24.6 : Corrected T2RCLK Mux selection options.
Figure 24.9 : Corrected T3RCLK Mux selection options.
C2 Register Definition 26.2 : Corrected DEVICEID value to 0x0C.
Revision 0.8 to Revision 1.0
•
•
•
•
•
•
Updated specification tables with full characterization data.
Updated Flash write and erase procedures to include a write to FLSCL.3-0.
Changed /RST pin comments in Table 4.1, “Pin Definitions for the C8051F41x,” on page 41 for the recommended pull-up resistor.
Changed the reset value of the SFR Definition 16.3. FLSCL: Flash Scale.
Removed the "Optional GND Connection" from Figure 4.5. ’Typical QFN-28 Landing Diagram’ on page 48.
Added a note regarding the maximum SYSCLK frequency to SFR Definition 19.4. CLKMUL: Clock Multiplier Control.
Revision 1.0 to Revision 1.1
•
•
•
•
•
•
268
Updated Figure 4.3. ’LQFP-32 Package Diagram’ on page 46, Figure 4.5. ’QFN-28 Package Drawing’ on
page 48, and Figure 4.6. ’QFN-28 Recommended PCB Land Pattern’ on page 49.
Added note that VIO must be > VDD in Table 3.1, “Global DC Electrical Characteristics,” on page 36.
Added information about ADC0 output register auto-clearing in SFR Definition 5.2.
Corrected ADC0 Tracking time equation in SFR Definition 5.6.
Clarified Voltage Regulator Electrical Specifications in Table 8.1 on page 82.
Added information about 16-bit and 32-bit CRC algorithms in Section 14.
Rev. 1.1
C8051F410/1/2/3
NOTES:
Rev. 1.1
269
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