Silicon Laboratories C8051F010 User Manual

C8051F000/1/2/5/6/7

a
ANALOG PERIPHERALS

- SAR ADC

 12-Bit (C8051F000/1/2, C8051F005/6/7)
 10-bit (C8051F010/1/2, C8051F015/6/7)
 ±1LSB INL; No Missing Codes
 Programmable Throughput up to 100ksps
 Up to 8 External Inputs; Programmable as Single-

- Two 12-bit DACs

- Two Analog Comparators

- Voltage Reference

- Precision VDD Monitor/Brown-out Detector

ON-CHIP JTAG DEBUG & BOUNDARY SCAN

- On-Chip Debug Circuitry Facilitates Full Speed, Non-

- Provides Breakpoints, Single Stepping, Watchpoints, Stack

- Inspect/Modify Memory and Registers

- Superior Performance to Emulation Systems Using ICE-

- IEEE1149.1 Compliant Boundary Scan

- Low Cost Development Kit

Ended or Differential

 Programmable Amplifier Gain: 16, 8, 4, 2, 1, 0.5
 Data Dependent Windowed Interrupt Generator
 Built-in Temperature Sensor (± 3°C)

 Programmable Hysteresis Values
 Configurable to Generate Interrupts or Reset

 2.4V; 15 ppm/°C
 Available on External Pin

Intrusive In-System Debug (No Emulator Required!)

Monitor

Chips, Target Pods, and Sockets

Mixed-Signal 32KB ISP FLASH MCU Family

C8051F010/1/2/5/6/7

HIGH SPEED 8051 µC CORE

- Pipelined Instruction Architecture; Executes 70% of
Instruction Set in 1 or 2 System Clocks

- Up to 25MIPS Throughput with 25MHz Clock

- 21 Vectored Interrupt Sources

MEMORY

- 256 Bytes Internal Data RAM (F000/01/02/10/11/12)

- 2304 Bytes Internal Data RAM (F005/06/07/15/16/17)

- 32k Bytes FLASH; In-System Programmable in 512 byte

Sectors

DIGITAL PERIPHERALS

- 4 Byte-Wide Port I/O; All are 5V tolerant

- Hardware SMBus

Serial Ports Available Concurrently

- Programmable 16-bit Counter/Timer Array with Five
Capture/Compare Modules

- Four General Purpose 16-bit Counter/Timers

- Dedicated Watch-Dog Timer

- Bi-directional Reset

CLOCK SOURCES

- Internal Programmable Oscillator: 2-to-16MHz

- External Oscillator: Crystal, RC,C, or Clock

- Can Switch Between Clock Sources on-the-fly; Useful in

Power Saving Modes

SUPPLY VOLTAGE ........................2.7V to 3.6V

- Typical Operating Current: 12.5mA @ 25MHz

- Multiple Power Saving Sleep and Shutdown Modes

64-Pin TQFP, 48-Pin TQFP, 32-Pin LQFP
Temperature Range: –40°C to +85°C

TM

(I2CTM Compatible), SPITM, and UART

ANALOG PERIPHERALS

TEMP

SENSOR

PGA

AMUX

VREF

SAR

ADC

12-Bit

DAC

12-Bit

DAC

+

-

COMPARATORS

+

-

VOLTAGE

DIGITAL I/O

PCA

SMBus

SPI Bus

UART

Timer 0

Timer 1

Timer 2

Timer 3

CROSSBAR

Port 0Port 1

Port 2Port 3

HIGH-SPEED CONTROLLER CORE

8051 CPU

(25MIPS)

32KB

ISP FLASH

CLOCK

CIRCUIT

256/2304 B

SRAM

JTAG

21

INTERRUPTS

DEBUG

CIRCUITRY

SANITY

CONTROL

Rev. 1.7 11/03 Copyright © 2003 by Silicon Laboratories

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

TABLE OF CONTENTS

1. SYSTEM OVERVIEW........................................................................................................8

Table 1.1. Product Selection Guide ...................................................................................................................8

Figure 1.1. C8051F000/05/10/15 Block Diagram .............................................................................................9

Figure 1.2. C8051F001/06/11/16 Block Diagram ...........................................................................................10

Figure 1.3. C8051F002/07/12/17 Block Diagram ...........................................................................................11

1.1. CIP-51TM CPU .......................................................................................................................................12

Figure 1.4. Comparison of Peak MCU Execution Speeds...............................................................................12

Figure 1.5. On-Board Clock and Reset............................................................................................................13

1.2. On-Board Memory.................................................................................................................................14

Figure 1.6. On-Board Memory Map................................................................................................................14

1.3. JTAG Debug and Boundary Scan..........................................................................................................15

Figure 1.7. Debug Environment Diagram .......................................................................................................15

1.4. Programmable Digital I/O and Crossbar ...............................................................................................16

Figure 1.8. Digital Crossbar Diagram..............................................................................................................16

1.5. Programmable Counter Array................................................................................................................17

Figure 1.9. PCA Block Diagram .....................................................................................................................17

1.6. Serial Ports.............................................................................................................................................17

1.7. Analog to Digital Converter ..................................................................................................................18

Figure 1.10. ADC Diagram .............................................................................................................................18

1.8. Comparators and DACs.........................................................................................................................19

Figure 1.11. Comparator and DAC Diagram...................................................................................................19

2. ABSOLUTE MAXIMUM RATINGS*.............................................................................20

3. GLOBAL DC ELECTRICAL CHARACTERISTICS...................................................20

4. PINOUT AND PACKAGE DEFINITIONS ....................................................................21

Table 4.1. Pin Definitions................................................................................................................................21

Figure 4.1. TQFP-64 Pinout Diagram .............................................................................................................23

Figure 4.2. TQFP-64 Package Drawing ..........................................................................................................24

Figure 4.3. TQFP-48 Pinout Diagram .............................................................................................................25

Figure 4.4. TQFP-48 Package Drawing ..........................................................................................................26

Figure 4.5. LQFP-32 Pinout Diagram .............................................................................................................27

Figure 4.6. LQFP-32 Package Drawing ..........................................................................................................28

5. ADC (12-Bit, C8051F000/1/2/5/6/7 Only).........................................................................29

Figure 5.1. 12-Bit ADC Functional Block Diagram........................................................................................29

5.1. Analog Multiplexer and PGA................................................................................................................29

5.2. ADC Modes of Operation......................................................................................................................30

Figure 5.2. 12-Bit ADC Track and Conversion Example Timing...................................................................30

Figure 5.3. Temperature Sensor Transfer Function.........................................................................................31

Figure 5.4. AMX0CF: AMUX Configuration Register (C8051F00x) ............................................................31

Figure 5.5. AMX0SL: AMUX Channel Select Register (C8051F00x)...........................................................32

Figure 5.6. ADC0CF: ADC Configuration Register (C8051F00x).................................................................33

Figure 5.7. ADC0CN: ADC Control Register (C8051F00x) ..........................................................................34

Figure 5.8. ADC0H: ADC Data Word MSB Register (C8051F00x) .............................................................35

Figure 5.9. ADC0L: ADC Data Word LSB Register (C8051F00x)...............................................................35

5.3. ADC Programmable Window Detector.................................................................................................36

Figure 5.10. ADC0GTH: ADC Greater-Than Data High Byte Register (C8051F00x) ..................................36

Figure 5.11. ADC0GTL: ADC Greater-Than Data Low Byte Register (C8051F00x) ...................................36

Figure 5.12. ADC0LTH: ADC Less-Than Data High Byte Register (C8051F00x) .......................................36

Figure 5.13. ADC0LTL: ADC Less-Than Data Low Byte Register (C8051F00x).........................................36

Figure 5.14. 12-Bit ADC Window Interrupt Examples, Right Justified Data.................................................37

Figure 5.15. 12-Bit ADC Window Interrupt Examples, Left Justified Data ...................................................37

Figure 5.15. 12-Bit ADC Window Interrupt Examples, Left Justified Data ...................................................38

Rev. 1.7 2

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 5.1. 12-Bit ADC Electrical Characteristics............................................................................................38

Table 5.1. 12-Bit ADC Electrical Characteristics............................................................................................39

6. ADC (10-Bit, C8051F010/1/2/5/6/7 Only).........................................................................40

Figure 6.1. 10-Bit ADC Functional Block Diagram........................................................................................40

6.1. Analog Multiplexer and PGA................................................................................................................40

6.2. ADC Modes of Operation......................................................................................................................41

Figure 6.2. 10-Bit ADC Track and Conversion Example Timing...................................................................41

Figure 6.3. Temperature Sensor Transfer Function.........................................................................................42

Figure 6.4. AMX0CF: AMUX Configuration Register (C8051F01x) ............................................................42

Figure 6.5. AMX0SL: AMUX Channel Select Register (C8051F01x)...........................................................43

Figure 6.6. ADC0CF: ADC Configuration Register (C8051F01x).................................................................44

Figure 6.7. ADC0CN: ADC Control Register (C8051F01x) ..........................................................................45

Figure 6.8. ADC0H: ADC Data Word MSB Register (C8051F01x) .............................................................46

Figure 6.9. ADC0L: ADC Data Word LSB Register (C8051F01x)...............................................................46

6.3. ADC Programmable Window Detector.................................................................................................47

Figure 6.10. ADC0GTH: ADC Greater-Than Data High Byte Register (C8051F01x) ..................................47

Figure 6.11. ADC0GTL: ADC Greater-Than Data Low Byte Register (C8051F01x) ...................................47

Figure 6.12. ADC0LTH: ADC Less-Than Data High Byte Register (C8051F01x) .......................................47

Figure 6.13. ADC0LTL: ADC Less-Than Data Low Byte Register (C8051F01x).........................................47

Figure 6.14. 10-Bit ADC Window Interrupt Examples, Right Justified Data.................................................48

Figure 6.15. 10-Bit ADC Window Interrupt Examples, Left Justified Data ...................................................48

Figure 6.15. 10-Bit ADC Window Interrupt Examples, Left Justified Data ...................................................49

Table 6.1. 10-Bit ADC Electrical Characteristics............................................................................................49

Table 6.1. 10-Bit ADC Electrical Characteristics............................................................................................50

7. DACs, 12 BIT VOLTAGE MODE....................................................................................51

Figure 7.1. DAC Functional Block Diagram....................................................................................................51

Figure 7.2. DAC0H: DAC0 High Byte Register .............................................................................................52

Figure 7.3. DAC0L: DAC0 Low Byte Register ..............................................................................................52

Figure 7.4. DAC0CN: DAC0 Control Register...............................................................................................52

Figure 7.5. DAC1H: DAC1 High Byte Register .............................................................................................53

Figure 7.6. DAC1L: DAC1 Low Byte Register ..............................................................................................53

Figure 7.7. DAC1CN: DAC1 Control Register...............................................................................................53

Table 7.1. DAC Electrical Characteristics.......................................................................................................54

8. COMPARATORS ..............................................................................................................55

Figure 8.1. Comparator Functional Block Diagram ........................................................................................55

Figure 8.2. Comparator Hysteresis Plot...........................................................................................................56

Figure 8.3. CPT0CN: Comparator 0 Control Register ....................................................................................57

Figure 8.4. CPT1CN: Comparator 1 Control Register ....................................................................................58

Table 8.1. Comparator Electrical Characteristics ............................................................................................59

9. VOLTAGE REFERENCE ................................................................................................60

Figure 9.1. Voltage Reference Functional Block Diagram .............................................................................60

Figure 9.2. REF0CN: Reference Control Register ..........................................................................................61

Table 9.1. Reference Electrical Characteristics ...............................................................................................61

10. CIP-51 CPU.........................................................................................................................62

Figure 10.1. CIP-51 Block Diagram................................................................................................................62

10.1. INSTRUCTION SET.........................................................................................................................63

Table 10.1. CIP-51 Instruction Set Summary..................................................................................................65

10.2. MEMORY ORGANIZATION..........................................................................................................68

Figure 10.2. Memory Map...............................................................................................................................69

10.3. SPECIAL FUNCTION REGISTERS................................................................................................70

Table 10.2. Special Function Register Memory Map......................................................................................70

Table 10.3. Special Function Registers ...........................................................................................................70

Figure 10.3. SP: Stack Pointer.........................................................................................................................74

Figure 10.4. DPL: Data Pointer Low Byte ......................................................................................................74

3 Rev. 1.7

C8051F000/1/2/5/6/7

Figure 10.5. DPH: Data Pointer High Byte .....................................................................................................74

Figure 10.6. PSW: Program Status Word........................................................................................................75

Figure 10.7. ACC: Accumulator......................................................................................................................76

Figure 10.8. B: B Register ...............................................................................................................................76

10.4. INTERRUPT HANDLER .................................................................................................................77

Table 10.4. Interrupt Summary........................................................................................................................78

Figure 10.9. IE: Interrupt Enable.....................................................................................................................79

Figure 10.10. IP: Interrupt Priority..................................................................................................................80

Figure 10.11. EIE1: Extended Interrupt Enable 1 ...........................................................................................81

Figure 10.12. EIE2: Extended Interrupt Enable 2 ...........................................................................................82

Figure 10.13. EIP1: Extended Interrupt Priority 1 ..........................................................................................83

Figure 10.14. EIP2: Extended Interrupt Priority 2 ..........................................................................................84

10.5. Power Management Modes ...............................................................................................................85

Figure 10.15. PCON: Power Control Register ................................................................................................86

C8051F010/1/2/5/6/7

11. FLASH MEMORY.............................................................................................................87

11.1. Programming The Flash Memory......................................................................................................87

Table 11.1. FLASH Memory Electrical Characteristics..................................................................................87

11.2. Non-volatile Data Storage .................................................................................................................88

11.3. Security Options ................................................................................................................................88

Figure 11.1. PSCTL: Program Store RW Control...........................................................................................88

Figure 11.2. Flash Program Memory Security Bytes .......................................................................................89

Figure 11.3. FLACL: Flash Access Limit (C8051F005/06/07/15/16/17 only) ...............................................90

Figure 11.4. FLSCL: Flash Memory Timing Prescaler ...................................................................................91

12. EXTERNAL RAM (C8051F005/06/07/15/16/17).............................................................92

Figure 12.1. EMI0CN: External Memory Interface Control ...........................................................................92

13. RESET SOURCES .............................................................................................................93

Figure 13.1. Reset Sources Diagram ...............................................................................................................93

13.1. Power-on Reset..................................................................................................................................94

13.2. Software Forced Reset.......................................................................................................................94

Figure 13.2. VDD Monitor Timing Diagram ..................................................................................................94

13.3. Power-fail Reset.................................................................................................................................94

13.4. External Reset....................................................................................................................................95

13.5. Missing Clock Detector Reset ...........................................................................................................95

13.6. Comparator 0 Reset ...........................................................................................................................95

13.7. External CNVSTR Pin Reset.............................................................................................................95

13.8. Watchdog Timer Reset ......................................................................................................................95

Figure 13.3. WDTCN: Watchdog Timer Control Register .............................................................................96

Figure 13.4. RSTSRC: Reset Source Register.................................................................................................97

Table 13.1. Reset Electrical Characteristics ....................................................................................................98

14. OSCILLATOR ...................................................................................................................99

Figure 14.1. Oscillator Diagram ......................................................................................................................99

Figure 14.2. OSCICN: Internal Oscillator Control Register .........................................................................100

Table 14.1. Internal Oscillator Electrical Characteristics ..............................................................................100

Figure 14.3. OSCXCN: External Oscillator Control Register.......................................................................101

14.1. External Crystal Example ................................................................................................................102

14.2. External RC Example ......................................................................................................................102

14.3. External Capacitor Example ............................................................................................................102

15. PORT INPUT/OUTPUT..................................................................................................103

15.1. Priority Cross Bar Decoder..............................................................................................................103

15.2. Port I/O Initialization.......................................................................................................................103

Figure 15.1. Port I/O Functional Block Diagram ..........................................................................................104

Figure 15.2. Port I/O Cell Block Diagram.....................................................................................................104

Table 15.1. Crossbar Priority Decode ...........................................................................................................105

Figure 15.3. XBR0: Port I/O CrossBar Register 0 ........................................................................................106

Rev. 1.7 4

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 15.4. XBR1: Port I/O CrossBar Register 1 ........................................................................................107

Figure 15.5. XBR2: Port I/O CrossBar Register 2 ........................................................................................108

15.3. General Purpose Port I/O.................................................................................................................109

15.4. Configuring Ports Which are not Pinned Out..................................................................................109

Figure 15.6. P0: Port0 Register .....................................................................................................................109

Figure 15.7. PRT0CF: Port0 Configuration Register ....................................................................................109

Figure 15.8. P1: Port1 Register .....................................................................................................................110

Figure 15.9. PRT1CF: Port1 Configuration Register ....................................................................................110

Figure 15.10. PRT1IF: Port1 Interrupt Flag Register....................................................................................110

Figure 15.11. P2: Port2 Register ...................................................................................................................111

Figure 15.12. PRT2CF: Port2 Configuration Register ..................................................................................111

Figure 15.13. P3: Port3 Register ...................................................................................................................112

Figure 15.14. PRT3CF: Port3 Configuration Register ..................................................................................112

Table 15.2. Port I/O DC Electrical Characteristics........................................................................................112

16. SMBus / I2C Bus...............................................................................................................113

Figure 16.1. SMBus Block Diagram .............................................................................................................113

Figure 16.2. Typical SMBus Configuration ..................................................................................................114

16.1. Supporting Documents ....................................................................................................................114

16.2. Operation .........................................................................................................................................115

Figure 16.3. SMBus Transaction...................................................................................................................115

16.3. Arbitration .......................................................................................................................................116

16.4. Clock Low Extension ......................................................................................................................116

16.5. Timeouts ..........................................................................................................................................116

16.6. SMBus Special Function Registers..................................................................................................116

Figure 16.4. SMB0CN: SMBus Control Register ..........................................................................................118

Figure 16.5. SMB0CR: SMBus Clock Rate Register....................................................................................119

Figure 16.6. SMB0DAT: SMBus Data Register ...........................................................................................120

Figure 16.7. SMB0ADR: SMBus Address Register .....................................................................................120

Figure 16.8. SMB0STA: SMBus Status Register..........................................................................................121

Table 16.1. SMBus Status Codes ..................................................................................................................122

17. SERIAL PERIPHERAL INTERFACE BUS.................................................................123

Figure 17.1. SPI Block Diagram ...................................................................................................................123

Figure 17.2. Typical SPI Interconnection......................................................................................................124

17.1. Signal Descriptions..........................................................................................................................124

17.2. Operation .........................................................................................................................................125

Figure 17.3. Full Duplex Operation...............................................................................................................125

17.3. Serial Clock Timing.........................................................................................................................126

Figure 17.4. Data/Clock Timing Diagram.....................................................................................................126

17.4. SPI Special Function Registers........................................................................................................127

Figure 17.5. SPI0CFG: SPI Configuration Register......................................................................................127

Figure 17.6. SPI0CN: SPI Control Register ..................................................................................................128

Figure 17.7. SPI0CKR: SPI Clock Rate Register..........................................................................................129

Figure 17.8. SPI0DAT: SPI Data Register ....................................................................................................129

18. UART.................................................................................................................................130

Figure 18.1. UART Block Diagram ..............................................................................................................130

18.1. UART Operational Modes...............................................................................................................131

Table 18.1. UART Modes .............................................................................................................................131

Figure 18.2. UART Mode 0 Interconnect......................................................................................................131

Figure 18.3. UART Mode 0 Timing Diagram...............................................................................................131

Figure 18.4. UART Mode 1 Timing Diagram...............................................................................................132

Figure 18.5. UART Modes 1, 2, and 3 Interconnect Diagram ......................................................................133

Figure 18.6. UART Modes 2 and 3 Timing Diagram....................................................................................134

18.2. Multiprocessor Communications.....................................................................................................135

Figure 18.7. UART Multi-Processor Mode Interconnect Diagram ...............................................................135

5 Rev. 1.7

C8051F000/1/2/5/6/7

Table 18.2. Oscillator Frequencies for Standard Baud Rates ........................................................................136

Figure 18.8. SBUF: Serial (UART) Data Buffer Register.............................................................................136

Figure 18.9. SCON: Serial Port Control Register..........................................................................................137

C8051F010/1/2/5/6/7

19. TIMERS ............................................................................................................................138

19.1. Timer 0 and Timer 1........................................................................................................................138

Figure 19.1. T0 Mode 0 Block Diagram........................................................................................................139

Figure 19.2. T0 Mode 2 Block Diagram........................................................................................................140

Figure 19.3. T0 Mode 3 Block Diagram........................................................................................................141

Figure 19.4. TCON: Timer Control Register.................................................................................................142

Figure 19.5. TMOD: Timer Mode Register...................................................................................................143

Figure 19.6. CKCON: Clock Control Register..............................................................................................144

Figure 19.7. TL0: Timer 0 Low Byte ............................................................................................................145

Figure 19.8. TL1: Timer 1 Low Byte ............................................................................................................145

Figure 19.9. TH0: Timer 0 High Byte ...........................................................................................................145

Figure 19.10. TH1: Timer 1 High Byte .........................................................................................................145

19.2. Timer 2 ............................................................................................................................................146

Figure 19.11. T2 Mode 0 Block Diagram......................................................................................................147

Figure 19.12. T2 Mode 1 Block Diagram......................................................................................................148

Figure 19.13. T2 Mode 2 Block Diagram......................................................................................................149

Figure 19.14. T2CON: Timer 2 Control Register..........................................................................................150

Figure 19.15. RCAP2L: Timer 2 Capture Register Low Byte ......................................................................151

Figure 19.16. RCAP2H: Timer 2 Capture Register High Byte .....................................................................151

Figure 19.17. TL2: Timer 2 Low Byte ..........................................................................................................151

Figure 19.18. TH2: Timer 2 High Byte .........................................................................................................151

19.3. Timer 3 ............................................................................................................................................152

Figure 19.19. Timer 3 Block Diagram...........................................................................................................152

Figure 19.20. TMR3CN: Timer 3 Control Register ......................................................................................152

Figure 19.21. TMR3RLL: Timer 3 Reload Register Low Byte ....................................................................153

Figure 19.22. TMR3RLH: Timer 3 Reload Register High Byte ...................................................................153

Figure 19.23. TMR3L: Timer 3 Low Byte ....................................................................................................153

Figure 19.24. TMR3H: Timer 3 High Byte...................................................................................................153

20. PROGRAMMABLE COUNTER ARRAY....................................................................154

Figure 20.1. PCA Block Diagram .................................................................................................................154

20.1. Capture/Compare Modules..............................................................................................................155

Table 20.1. PCA0CPM Register Settings for PCA Capture/Compare Modules ...........................................155

Figure 20.2. PCA Interrupt Block Diagram...................................................................................................155

Figure 20.3. PCA Capture Mode Diagram ....................................................................................................156

Figure 20.4. PCA Software Timer Mode Diagram........................................................................................157

Figure 20.5. PCA High Speed Output Mode Diagram..................................................................................157

Figure 20.6. PCA PWM Mode Diagram .......................................................................................................158

20.2. PCA Counter/Timer.........................................................................................................................159

Table 20.2. PCA Timebase Input Options.....................................................................................................159

Figure 20.7. PCA Counter/Timer Block Diagram.........................................................................................159

20.3. Register Descriptions for PCA ........................................................................................................160

Figure 20.8. PCA0CN: PCA Control Register ...............................................................................................160

Figure 20.9. PCA0MD: PCA Mode Register ................................................................................................161

Figure 20.10. PCA0CPMn: PCA Capture/Compare Registers......................................................................162

Figure 20.11. PCA0L: PCA Counter/Timer Low Byte .................................................................................163

Figure 20.12. PCA0H: PCA Counter/Timer High Byte ................................................................................163

Figure 20.13. PCA0CPLn: PCA Capture Module Low Byte........................................................................163

Figure 20.14. PCA0CPHn: PCA Capture Module High Byte.......................................................................163

21. JTAG (IEEE 1149.1) ........................................................................................................164

Figure 21.1. IR: JTAG Instruction Register ..................................................................................................164

21.1. Boundary Scan.................................................................................................................................165

Rev. 1.7 6

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 21.1. Boundary Data Register Bit Definitions.....................................................................................165

Figure 21.2. DEVICEID: JTAG Device ID Register ....................................................................................166

21.2. Flash Programming Commands.......................................................................................................167

Figure 21.3. FLASHCON: JTAG Flash Control Register.............................................................................168

Figure 21.4. FLASHADR: JTAG Flash Address Register............................................................................168

Figure 21.5. FLASHDAT: JTAG Flash Data Register..................................................................................169

Figure 21.6. FLASHSCL: JTAG Flash Scale Register .................................................................................169

21.3. Debug Support.................................................................................................................................170

7 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

1. SYSTEM OVERVIEW

The C8051F000 family are fully integrated mixed-signal System on a Chip MCUs with a true 12-bit multi-channel
ADC (F000/01/02/05/06/07), or a true 10-bit multi-channel ADC (F010/11/12/15/16/17). See the Product Selection
Guide in Table 1.1 for a quick reference of each MCUs’ feature set. Each has a programmable gain pre-amplifier,
two 12-bit DACs, two voltage comparators (except for the F002/07/12/17, which have one), a voltage reference,
and an 8051-compatible microcontroller core with 32kbytes of FLASH memory. There are also I2C/SMBus,
UART, and SPI serial interfaces implemented in hardware (not “bit-banged” in user software) as well as a
Programmable Counter/Timer Array (PCA) with five capture/compare modules. There are also 4 general-purpose
16-bit timers and 4 byte-wide general-purpose digital Port I/O. The C8051F000/01/02/10/11/12 have 256 bytes of
RAM and execute up to 20MIPS, while the C8051F005/06/07/15/16/17 have 2304 bytes of RAM and execute up to
25MIPS.

With an on-board VDD monitor, WDT, and clock oscillator, the MCUs are truly stand-alone System-on-a-Chip
solutions. Each MCU effectively configures and manages the analog and digital peripherals. The FLASH memory
can be reprogrammed even in-circuit, providing non-volatile data storage, and also allowing field upgrades of the
8051 firmware. Each MCU can also individually shut down any or all of the peripherals to conserve power.

On-board JTAG debug support allows non-intrusive (uses no on-chip resources), full speed, in-circuit debug using
the production MCU installed in the final application. This debug system supports inspection and modification of
memory and registers, setting breakpoints, watchpoints, single stepping, and run and halt commands. All analog
and digital peripherals are fully functional when using JTAG debug.

Each MCU is specified for 2.7V-to-3.6V operation over the industrial temperature range (-45C to +85C). The Port
I/Os, /RST, and JTAG pins are tolerant for input signals up to 5V. The C8051F000/05/10/15 are available in the
64-pin TQFP (see block diagram in Figure 1.1). The C8051F001/06/11/16 are available in the 48-pin TQFP (see
block diagram in Figure 1.2). The C8051F002/07/12/17 are available in the 32-pin LQFP (see block diagram in
Figure 1.3).

Table 1.1. Product Selection Guide

C8051F000 20 32k 256

C8051F001 20 32k 256

C8051F002 20 32k 256

C8051F005 25 32k 2304

C8051F006 25 32k 2304

C8051F007 25 32k 2304

C8051F010 20 32k 256

C8051F011 20 32k 256

C8051F012 20 32k 256

C8051F015 25 32k 2304

C8051F016 25 32k 2304

C8051F017 25 32k 2304

MIPS (Peak)

FLASH Memory

RAM

SMBus/I2C

SPI

√ √ √
√ √ √
√ √ √
√ √ √
√ √ √
√ √ √
√ √ √
√ √ √
√ √ √
√ √ √
√ √ √
√ √ √

UART

4

4

4

4

4

4

4

4

4

4

4

4

Timers (16-bit)

Programmable Counter Array

Digital Port I/O’s

ADC Resolution (bits)

ADC Max Speed (ksps)

ADC Inputs

Voltage Reference

Temperature Sensor

DAC Resolution

DAC Outputs

Voltage Comparators

Package

32 12 100 8

√

16 12 100 8

√

8 12 100 4

√

32 12 100 8

√

16 12 100 8

√

8 12 100 4

√

32 10 100 8

√

16 10 100 8

√

8 10 100 4

√

32 10 100 8

√

16 10 100 8

√

8 10 100 4

√

√ √
√ √
√ √
√ √
√ √
√ √
√ √
√ √
√ √
√ √
√ √
√ √

12 2 2 64TQFP

12 2 2 48TQFP

12 2 1 32LQFP

12 2 2 64TQFP

12 2 2 48TQFP

12 2 1 32LQFP

12 2 2 64TQFP

12 2 2 48TQFP

12 2 1 32LQFP

12 2 2 64TQFP

12 2 2 48TQFP

12 2 1 32LQFP

Rev. 1.7 8

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 1.1. C8051F000/05/10/15 Block Diagram

VDD
VDD

VDD
DGND
DGND
DGND

AV+

AV+
AGND
AGND

TCK

TMS

TDI

TDO

/RST

XTAL1
XTAL2

VREF

DAC0

DAC1

AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7

CP0+

CP0-

CP1+

CP1-

Digital Power

Analog Power

VREF

JTAG
Logic

VDD

Monitor

External

Oscillator

Circuit

Internal

Oscillator

DAC0

(12-Bit)

DAC1

(12-Bit)

Boundary Scan

Debug HW

WDT

System Clock

Reset

8

0

5

1

C

o

r

e

32kbyte

FLASH

256 byte

RAM

2048 byte

XRAM

(F005/15 only)

SFR Bus

UART

SMBus

SPI Bus

PCA

Timers

0,1,2

Timer 3

Port 0
Latch

Port 1
Latch

Port 2
Latch

Port 3
Latch

C

R

O

S

S

B

A

R

S

W

I

T

C

H

A
M
U
X

CP0

CP1

Prog
Gain

TEMP

ADC

100ksps

P
0

D

r

v

P
1

D

r

v

P
2

D

r

v

P
3

D

r

v

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

P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7

9 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 1.2. C8051F001/06/11/16 Block Diagram

VDD

VDD

DGND
DGND
DGND
DGND

AV+

AV+

AGND
AGND

TCK

TMS

TDI

TDO

/RST

XTAL1
XTAL2

VREF

DAC0

DAC1

AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7

CP0+

CP0-

CP1+

CP1-

Digital Power

Analog Power

VREF

JTAG
Logic

VDD

Monitor

External

Oscillator

Circuit

Internal

Oscillator

DAC0

(12-Bit)

DAC1

(12-Bit)

Boundary Scan

Debug HW

WDT

Reset

System Clock

8

0

5

1

C

o

r

e

32kbyte

FLASH

256 byte

RAM

2048 byte

XRAM

(F006/16 only)

SFR Bus

UART

SMBus

SPI Bus

PCA

Timers

0,1,2

Timer 3

Port 0

Latch

Port 1

Latch

Port 2

Latch

Port 3

Latch

C

R

O

S

S

B

A

R

S

W

I

T

C

H

A
M
U
X

CP0

CP1

Prog
Gain

TEMP

ADC

100ksps

P
0

D

r

v

P
1

D

r

v

P
2

D

r

v

P
3

D

r

v

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

Rev. 1.7 10

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 1.3. C8051F002/07/12/17 Block Diagram

VDD

VDD

DGND
DGND

AV+

AV+

AGND
AGND

TCK

TMS

TDI

TDO

/RST

XTAL1
XTAL2

VREF

DAC0

DAC1

AIN0
AIN1
AIN2
AIN3

CP0+

CP0-

Digital Power

Analog Power

VREF

A
M
U
X

JTAG
Logic

VDD

Monitor

External

Oscillator

Circuit

Internal

Oscillator

DAC0

(12-Bit)

DAC1

(12-Bit)

Prog
Gain

CP0

CP1

Boundary Scan

Debug HW

WDT

TEMP

System Clock

ADC

100ksps

Reset

8

0

5

1

C

o

r

e

32kbyte

FLASH

256 byte

RAM

2048 byte

XRAM

(F007/17 only)

SFR Bus

UART

SMBus

SPI Bus

PCA

Timers

0,1,2

Timer 3

Port 0

Latch

Port 1

Latch

Port 2

Latch

Port 3

Latch

C

R

O

S

S

B

A

R

S

W

I

T

C

H

P
0

D

r
v

P
1

D

r
v

P
2

D

r
v

P
3

D

r
v

P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7

11 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

1.1. CIP-51TM CPU

1.1.1. Fully 8051 Compatible

The C8051F000 family utilizes Silicon Laboratories’ proprietary CIP-51 microcontroller core. The CIP-51 is fully
compatible with the MCS-51
develop software. The core has all the peripherals included with a standard 8052, including four 16-bit
counter/timers, a full-duplex UART, 256 bytes of internal RAM space, 128 byte Special Function Register (SFR)
address space, and four byte-wide I/O Ports.

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 with a maximum system clock of 12-to-24MHz. By contrast, the CIP-51 core executes 70% of its
instructions in one or two system clock cycles, with only four instructions taking more than four system clock
cycles.

The CIP-51 has a total of 109 instructions. The number of instructions versus the system clock cycles to execute
them is as follows:

Instructions

Clocks to Execute

With the CIP-51’s maximum system clock at 25MHz, it has a peak throughput of 25MIPS. Figure 1.4 shows a
comparison of peak throughputs of various 8-bit microcontroller cores with their maximum system clocks.

TM

instruction set. Standard 803x/805x assemblers and compilers can be used to

26 50 5 14 7 3 1 2 1

1 2 2/3 3 3/4 4 4/5 5 8

Figure 1.4. Comparison of Peak MCU Execution Speeds

25

20

15

MIPS

10

5

Silicon Labs

CIP-51

(25MHz clk)

Microchip

PIC17C75x

(33MHz clk)

Philips

80C51

(33MHz clk)

ADuC812

8051

(16MHz clk)

Rev. 1.7 12

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

1.1.3. Additional Features

The C8051F000 MCU family has several key enhancements both inside and outside the CIP-51 core to improve its
overall performance and ease of use in the end applications.

The extended interrupt handler provides 21 interrupt sources into the CIP-51 (as opposed to 7 for the standard

8051), allowing the numerous analog and digital peripherals to interrupt the controller. An interrupt driven system
requires less intervention by the MCU, giving it more effective throughput. The extra interrupt sources are very
useful when building multi-tasking, real-time systems.

There are up to seven reset sources for the MCU: an on-board VDD monitor, a Watchdog Timer, a missing clock
detector, a voltage level detection from Comparator 0, a forced software reset, the CNVSTR pin, and the /RST pin.
The /RST pin is bi-directional, accommodating an external reset, or allowing the internally generated POR to be
output on the /RST pin. Each reset source except for the VDD monitor and Reset Input Pin 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 MCU has an internal, stand alone clock generator which is used by default as the system clock after any reset.
If desired, the clock source may be switched on the fly to the external oscillator, which can use a crystal, ceramic
resonator, capacitor, RC, or external clock source to generate the system clock. This can be extremely useful in low
power applications, allowing the MCU to run from a slow (power saving) external crystal source, while periodically
switching to the fast (up to 16MHz) internal oscillator as needed.

Figure 1.5. On-Board Clock and Reset

(Port

I/O)

Crossbar

CP0+

CP0-

CNVSTR

(CNVSTR

reset

enable)

Comparator 0

+

-

(CP0

reset

enable)

Missing

Detector

Internal

Clock

XTAL1

XTAL2

Generator

OSC

System
Clock

Clock Select

VDD

WDT

WDT

EN

Enable

Clock

(one-

shot)

EN

MCD

Enable

CIP-51

Microcontroller

Core

Supply
Monitor

+

-

PRE

WDT

Supply

Reset

Timeout

Strobe

Software Reset

System Reset

(wired-OR)

Reset
Funnel

/RST

Extended Interrupt

Handler

13 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

1.2. On-Board 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.

The CIP-51 in the C8051F005/06/07/15/16/17 MCUs additionally has a 2048 byte RAM block in the external data
memory address space. This 2048 byte block can be addressed over the entire 64k external data memory address
range (see Figure 1.6).

The MCU’s program memory consists of 32k + 128 bytes of FLASH. This memory may be reprogrammed in­system in 512 byte sectors, and requires no special off-chip programming voltage. The 512 bytes from addresses
0x7E00 to 0x7FFF are reserved for factory use. There is also a single 128-byte sector at address 0x8000 to 0x807F,
which may be useful as a small table for software constants or as additional program space. See Figure 1.6 for the
MCU system memory map.

Figure 1.6. On-Board Memory Map

0x807F

0x8000

0x7FFF

0x7E00

0x7DFF

0x0000

PROGRAM MEMORY

128 Byte ISP FLASH

RESERVED

FLASH

(In-System

Programmable in 512

Byte Sectors)

0xFF

0x80
0x7F

0x30

0x2F

0x20

0x1F

0x00

DATA MEMORY

INTERNAL DATA ADDRESS SPACE

Upper 128 RAM

(Indirect Addressing

Only)

(Direct and Indirect

Addressing)

Bit Addressable

General Purpose

Registers

Special Function

Register's

(Direct Addressing Only)

Lower 128 RAM
(Direct and Indirect
Addressing)

EXTERNAL DATA ADDRESS SPACE

0xFFFF

0xF800

0x17FF

0x1000

0x0FFF

0x0800

0x07FF

0x0000

(same 2048 byte RAM block )

(same 2048 byte RAM block )

(same 2048 byte RAM block )

RAM - 2048 Bytes

(accessable using MOVX

instruction)

The same 2048 byte RAM
block can be addressed on
2k boundaries throughout
the 64k External Data
Memory space.

Rev. 1.7 14

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

1.3. JTAG Debug and Boundary Scan

The C8051F000 family has on-chip JTAG and debug circuitry that provide non-intrusive, full speed, in-circuit
debug using the production part installed in the end application using the four-pin JTAG I/F. The JTAG port is

fully compliant to IEEE 1149.1, providing full boundary scan for test and manufacturing purposes.

Silicon Labs’ debug system supports inspection and modification of memory and registers, breakpoints,
watchpoints, a stack monitor, 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) are stalled when the MCU is halted, during single
stepping, or at a breakpoint in order to keep them in sync.

The C8051F000DK, C8051F005DK, C8051F010DK, and C8051F015DK are development kits with all the
hardware and software necessary to develop application code and perform in-circuit debug with the C8051F000/1/2,
F005/6/7, F010/1/2, and F015/6/7 MCUs respectively. The kit includes software with a developer’s studio and
debugger, an integrated 8051 assembler, and an RS-232 to JTAG protocol translator module referred to as the EC.
It also has a target application board with the associated MCU installed and a large prototyping area, plus the RS­232 and JTAG cables, and wall-mount power supply. The Development Kit requires a Windows
95/98/NT/2000/XP computer with one available RS-232 serial port. As shown in Figure 1.7, the PC is connected
via RS-232 to the EC. A six-inch ribbon cable connects the EC to the user’s application board, picking up the four
JTAG pins and VDD and GND. The EC takes its power from the application board. It requires roughly 20mA at

2.7-3.6V. For applications where there is not sufficient power available from the target board, the provided power
supply can be connected directly to the EC.

This is a vastly superior configuration for developing and debugging embedded applications compared to standard
MCU Emulators, which use on-board “ICE Chips” and target cables and require the MCU in the application board
to be socketed. Silicon Labs’ debug environment both increases ease of use and preserves the performance of the
precision analog peripherals.

Figure 1.7. Debug Environment Diagram

TARGET PCB

C8051F000/1/2/5/6/7

C8051F000/1/2/5/6/7

1.4. Programmable Digital I/O and Crossbar

The standard 8051 Ports (0, 1, 2, and 3) are available on the MCUs. All four ports are pinned out on the
F000/05/10/15. Ports 0 and 1 are pinned out on the F001/06/11/16, and onl

C8051F010/1/2/5/6/7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

1.5. Programmable Counter Array

The C8051F000 MCU family has an on-board Programmable Counter/Timer Array (PCA) in addition to the four
16-bit general-purpose counter/timers. The PCA consists of a dedicated 16-bit counter/timer timebase with 5
programmable capture/compare modules. The timebase gets its clock from one of four sources: the system clock
divided by 12, the system clock divided by 4, Timer 0 overflow, or an External Clock Input (ECI).

Each capture/compare module can be configured to operate in one of four modes: Edge-Triggered Capture,
Software Timer, High Speed Output, or Pulse Width Modulator. The PCA Capture/Compare Module I/O and
External Clock Input are routed to the MCU Port I/O via the Digital Crossbar.

Figure 1.9. PCA Block Diagram

System

Clock

T0 Overflow

/4

/12

16-Bit Counter/Timer

Capture/Compare

Module 0

Capture/Compare

Module 1

Capture/Compare

Module 2

Capture/Compare

Module 3

Capture/Compare

Module 4

ECI

CEX0

CEX1

CEX2

CEX3

CEX4

Crossbar

Port I/O

1.6. Serial Ports

The C8051F000 MCU Family includes a Full-Duplex UART, SPI Bus, and I2C/SMBus. Each of the serial buses is
fully implemented in hardware and makes extensive use of the CIP-51’s interrupts, thus requiring very little
intervention by the CPU. The serial buses do not “share” resources such as timers, interrupts, or Port I/O, so any or
all of the serial buses may be used together.

17 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

1.7. Analog to Digital Converter

The C8051F000/1/2/5/6/7 has an on-chip 12-bit SAR ADC with a 9-channel input multiplexer and programmable
gain amplifier. With a maximum throughput of 100ksps, the ADC offers true 12-bit accuracy with an INL of
±1LSB. The ADC in the C8051F010/1/2/5/6/7 is similar, but with 10-bit resolution. Each ADC has a maximum
throughput of 100ksps. Each ADC has an INL of ±1LSB, offering true 12-bit accuracy with the C8051F00x, and
true 10-bit accuracy with the C8051F01x. There is also an on-board 15ppm voltage reference, or an external
reference may be used via the VREF pin.

The ADC is under full control of the CIP-51 microcontroller via the Special Function Registers. One input channel
is tied to an internal temperature sensor, while the other eight channels are available externally. Each pair of the
eight external input channels can be configured as either two single-ended inputs or a single differential input. The
system controller can also put the ADC into shutdown to save power.

A programmable gain amplifier follows the analog multiplexer. The gain can be set in software from 0.5 to 16 in
powers of 2. The gain stage can be especially useful when different ADC input channels have widely varied input
voltage signals, or when it is necessary to “zoom in” on a signal with a large DC offset (in differential mode, a DAC
could be used to provide the DC offset).

Conversions can be started in four ways; a software command, an overflow on Timer 2, an overflow on Timer 3, or
an external signal input. This flexibility allows the start of conversion to be triggered by software events, external
HW signals, or convert continuously. A completed conversion causes an interrupt, or a status bit can be polled in
software to determine the end of conversion. The resulting 10 or 12-bit data word is latched into two SFRs upon
completion of a conversion. The data can be right or left justified in these registers under software control.

Compare registers for the ADC data can be configured to interrupt the controller when ADC data is within a
specified window. The ADC can monitor a key voltage continuously in background mode, but not interrupt the
controller unless the converted data is within the specified window.

Figure 1.10. ADC Diagram

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

(not bonded out on
F002, F007, F012,
and F017

+

-

+

-

+

-

+

-

9-to-1
AMUX
(SE or

DIFF)

SENSOR

TEMP

Programmable

Gain Amp

+

X

-

Control & Data

SFR's

REF

100ksps

SAR

ADC

SFR Bus

VREF

Rev. 1.7 18

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

1.8. Comparators and DACs

The C8051F000 MCU Family has two 12-bit DACs and two comparators on chip (the second comparator, CP1, is
not bonded out on the F002, F007, F012, and F017). The MCU data and control interface to each comparator and
DAC is via the Special Function Registers. The MCU can place any DAC or comparator in low power shutdown
mode.

The comparators have software programmable hysteresis. Each comparator can generate an interrupt on its rising
edge, falling edge, or both. The comparators’ output state can also be polled in software. These interrupts are
capable of waking up the MCU from idle mode. The comparator outputs can be programmed to appear on the Port
I/O pins via the Crossbar.

The DACs are voltage output mode and use the same voltage reference as the ADC. They are especially useful as
references for the comparators or offsets for the differential inputs of the ADC.

Figure 1.11. Comparator and DAC Diagram

(Port I/O)

(Port I/O)

CP0

CP1

CROSSBAR

CP0+

CP0-

CP1+

CP1-

DAC0

REF

DAC0

CP0

CP1

SFR's

(Data

and

Cntrl)

CIP-51

and

Interrupt

Handler

DAC1

REF

DAC1

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

2. ABSOLUTE MAXIMUM RATINGS*

Ambient temperature under bias................................................................................................................. -55 to 125°C

Storage Temperature .................................................................................................................................. -65 to 150°C

Voltage on any Pin (except VDD and Port I/O) with respect to DGND...................................-0.3V to (VDD + 0.3V)

Voltage on any Port I/O Pin or /RST with respect to DGND....................................................................-0.3V to 5.8V

Voltage on VDD with respect to DGND...................................................................................................-0.3V to 4.2V

Maximum Total current through VDD, AV+, DGND and AGND.....................................................................800mA

Maximum output current sunk by any Port pin...................................................................................................100mA

Maximum output current sunk by any other I/O pin.............................................................................................25mA

Maximum output current sourced by any Port pin ..............................................................................................100mA

Maximum output current sourced by any other I/O pin ........................................................................................ 25mA

*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.

3. GLOBAL DC ELECTRICAL CHARACTERISTICS

-40°C to +85°C unless otherwise specified.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Analog Supply Voltage (Note 1) 2.7 3.0 3.6 V
Analog Supply Current Internal REF, ADC, DAC, Comparators

all active
Analog Supply Current with
analog sub-systems inactive
Analog-to-Digital Supply
Delta ( | VDD – AV+ | )
Digital Supply Voltage 2.7 3.0 3.6 V
Digital Supply Current with
CPU active

Digital Supply Current
(shutdown)
Digital Supply RAM Data
Retention Voltage
Specified Operating
Temperature Range
SYSCLK (System Clock
Frequency)
SYSCLK (System Clock
Frequency)
Tsysl (SYSCLK Low Time) 18 ns
Tsysh (SYSCLK High Time) 18 ns

Note 1: Analog Supply AV+ must be greater than 1V for VDD monitor to operate.
Note 2: SYSCLK must be at least 32 kHz to enable debugging.

Internal REF, ADC, DAC, Comparators

all disabled, oscillator disabled

0.5 V

VDD = 2.7V, Clock=25MHz

VDD = 2.7V, Clock=1MHz

VDD = 2.7V, Clock=32kHz

Oscillator not running 5

1.5 V

-40 +85

C8051F005/6/7, C8051F015/6/7

(Note 2)

C8051F000/1/2, C8051F010/1/2

(Note 2)

1 2 mA

5 20

12.5

0.5
10

0 25 MHz

0 20 MHz

mA

µA

mA

µA
µA

°C

Rev. 1.7 20

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

4. PINOUT AND PACKAGE DEFINITIONS

Table 4.1. Pin Definitions

Pin Numbers

F000

F001

Name

VDD

DGND

AV+

AGND

TCK

TMS

TDI

TDO

XTAL1

XTAL2

/RST

VREF

CP0+

CP0-

CP1+

CP1-

DAC0

DAC1

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

F005
F010
F015

31,
40,

62
30,
41,

61

16,

17

5,
15
22 18 14
21 17 13
28 20 15

29 21 16

18 14 10

19 15 11

20 16 12

6 3 3

4 2 2
3 1 1
2 45
1 46

64 48 32

63 47 31

7 4 4

8 5 5

9 6 6

10 7 7

11 8

12 9

F006
F011
F016

23,

32

22,
33,
27,

19

13,

43

44,

12

F002
F007
F012
F017

18,

20

17,

21

9,

29

8,

30

Type Description

D In

D In

D In

D Out

A In

A Out

D I/O

A I/O

A In

A In

A In

A In

A Out

A Out

A In

A In

A In

A In

A In

A In

Digital Voltage Supply.

Digital Ground.

Positive Analog Voltage Supply.

Analog Ground.

JTAG Test Clock with internal pull-up.
JTAG Test-Mode Select with internal pull-up.
JTAG Test Data Input with internal pull-up. TDI is latched on a rising edge of

TCK.
JTAG Test Data Output with internal pull-up. Data is shifted out on TDO on
the falling edge of TCK. TDO output is a tri-state driver.
Crystal Input. This pin is the return for the internal oscillator circuit for a
crystal or ceramic resonator. For a precision internal clock, connect a crystal
or ceramic resonator from XTAL1 to XTAL2. If overdriven by an external
CMOS clock, this becomes the system clock.
Crystal Output. This pin is the excitation driver for a crystal or ceramic
resonator.
Chip Reset. Open-drain output of internal Voltage Supply monitor. Is driven
low when VDD is < 2.7V. An external source can force a system reset by
driving this pin low.
Voltage Reference. When configured as an input, this pin is the voltage
reference for the MCU. Otherwise, the internal reference drives this pin.
Comparator 0 Non-Inverting Input.

Comparator 0 Inverting Input.
Comparator 1 Non-Inverting Input.
Comparator 1 Inverting Input.
Digital to Analog Converter Output 0. The DAC0 voltage output. (See

Section 7 DAC Specification for complete description).
Digital to Analog Converter Output 1. The DAC1 voltage output. (See
Section 7 DAC Specification for complete description).
Analog Mux Channel Input 0. (See ADC Specification for complete
description).
Analog Mux Channel Input 1. (See ADC Specification for complete
description).
Analog Mux Channel Input 2. (See ADC Specification for complete
description).
Analog Mux Channel Input 3. (See ADC Specification for complete
description).
Analog Mux Channel Input 4. (See ADC Specification for complete
description).
Analog Mux Channel Input 5. (See ADC Specification for complete
description).

21 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Pin Numbers

F000

F001

Name

AIN6

AIN7

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

P3.0

P3.1

P3.2

P3.3

P3.4

P3.5

P3.6

P3.7

F005
F010
F015

13 10

14 11

39 31 19
42 34 22
47 35 23
48 36 24
49 37 25
50 38 26
55 39 27
56 40 28
38 30
37 29
36 28
35 26
34 25
32 24
60 42
59 41
33
27
54
53
52
51
44
43
26
25
24
23
58
57
46
45

F006
F011
F016

F002
F007
F012
F017

Type Description

A In

A In

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

D I/O

Analog Mux Channel Input 6. (See ADC Specification for complete
description).
Analog Mux Channel Input 7. (See ADC Specification for complete
description).
Port0 Bit0. (See the Port I/O Sub-System section for complete description).

Port0 Bit1. (See the Port I/O Sub-System section for complete description).
Port0 Bit2. (See the Port I/O Sub-System section for complete description).
Port0 Bit3. (See the Port I/O Sub-System section for complete description).
Port0 Bit4. (See the Port I/O Sub-System section for complete description).
Port0 Bit5. (See the Port I/O Sub-System section for complete description).
Port0 Bit6. (See the Port I/O Sub-System section for complete description).
Port0 Bit7. (See the Port I/O Sub-System section for complete description).
Port1 Bit0. (See the Port I/O Sub-System section for complete description).
Port1 Bit1. (See the Port I/O Sub-System section for complete description).
Port1 Bit2. (See the Port I/O Sub-System section for complete description).
Port1 Bit3. (See the Port I/O Sub-System section for complete description).
Port1 Bit4. (See the Port I/O Sub-System section for complete description).
Port1 Bit5. (See the Port I/O Sub-System section for complete description).
Port1 Bit6. (See the Port I/O Sub-System section for complete description).
Port1 Bit7. (See the Port I/O Sub-System section for complete description).
Port2 Bit0. (See the Port I/O Sub-System section for complete description).
Port2 Bit1. (See the Port I/O Sub-System section for complete description).
Port2 Bit2. (See the Port I/O Sub-System section for complete description).
Port2 Bit3. (See the Port I/O Sub-System section for complete description).
Port2 Bit4. (See the Port I/O Sub-System section for complete description).
Port2 Bit5. (See the Port I/O Sub-System section for complete description).
Port2 Bit6. (See the Port I/O Sub-System section for complete description).
Port2 Bit7. (See the Port I/O Sub-System section for complete description).
Port3 Bit0. (See the Port I/O Sub-System section for complete description).
Port3 Bit1. (See the Port I/O Sub-System section for complete description).
Port3 Bit2. (See the Port I/O Sub-System section for complete description).
Port3 Bit3. (See the Port I/O Sub-System section for complete description).
Port3 Bit4. (See the Port I/O Sub-System section for complete description).
Port3 Bit5. (See the Port I/O Sub-System section for complete description).
Port3 Bit6. (See the Port I/O Sub-System section for complete description).
Port3 Bit7. (See the Port I/O Sub-System section for complete description).

Rev. 1.7 22

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 4.1. TQFP-64 Pinout Diagram

CP1-

CP1+

CP0-

CP0+

AGND

VREF

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

AGND

AV+

10

11

15

16

1

2

3

4

5

6

7

8

9

12

13

14

DAC0

64

17

DAC1

63

AV+

VDD

62

18

19

XTAL1

XTAL2

P3.5

P3.4

57

P0.7

56

DGND

61

60

P1.6

P1.7

59

58

C8051F000
C8051F005
C8051F010
C8051F015

20

21

22

23

24

25

TCK

TMS

/RST

P3.3

P3.1

P3.2

P0.6

55

26

P2.2

P2.3

53

54

27

P3.0

P2.1

28

TDI

P2.4

52

29

TDO

P2.5

51

30

DGND

P0.5

50

31

P0.4

49

VDD

48

47

46

45

44

43

42

41

40

39

38

37

36

35

34

33

32

P1.5

P0.3

P0.2
P3.6

P3.7

P2.6

P2.7

P0.1

DGND

VDD

P0.0

P1.0

P1.1

P1.2

P1.3

P1.4

P2.0

23 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 4.2. TQFP-64 Package Drawing

64

PIN 1

DESIGNATOR

1

A2

D

D1

MIN

NOM

MAX

(mm)

(mm)

(mm)

A

-

-

1.20

A1

0.05

E1

E

e

A

b

A1

A2

b

D

D1

e

E

E1

0.95

0.17

-

0.15

-

1.05

0.22

0.27

-

12.00

-

10.00

-

0.50

-

12.00

-

10.00

-

-

-

-

-

Rev. 1.7 24

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 4.3. TQFP-48 Pinout Diagram

AGND

CP0-

CP0+

VREF

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

DAC0

48

1

2

3

4

5

6

7

8

9

10

11

12

13

AV+

CP1-

DAC1

47

46

14

15

XTAL2

XTAL1

CP1+

45

AGND

44

AV+

43

P1.6

42

P1.7

41

C8051F001
C8051F006
C8051F011
C8051F016

16

17

18

19

20

/RST

TMS

TCK

TDI

DGND

P0.7

40

21

TDO

P0.5

P0.6

39

38

22

23

VDD

DGND

P0.4

37

36

35

34

33

32

31

30

29

28

27

26

25

24

P1.5

P0.3

P0.2

P0.1

DGND

VDD

P0.0

P1.0

P1.1

P1.2

DGND

P1.3

P1.4

25 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 4.4. TQFP-48 Package Drawing

48

PIN 1

IDENTIFIER

A2

1

D

D1

E1

E

e

A

A1

b

A

A1

A2

b

D

D1

e

E

E1

MIN

(mm)

-

0.05

0.95

0.17

-

-

-

-

-

NOM

(mm)

-

-

1.00

0.22

9.00

7.00

0.50

9.00

7.00

MAX

(mm)

1.20

0.15

1.05

0.27

-

-

-

-

-

Rev. 1.7 26

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 4.5. LQFP-32 Pinout Diagram

AGND

CP0-

CP0+

VREF

AIN0

AIN1

AIN2

AIN3

DAC0

32

DAC1

31

AGND

30

AV+

29

P0.7

28

1

2

3

4

5

6

C8051F002
C8051F007
C8051F012
C8051F017

7

8

9

10

11

12

13

AV+

XTAL1

XTAL2

/RST

TMS

P0.6

27

14

TCK

P0.5

26

15

TDI

P0.4

25

16

TDO

24

23

22

21

20

19

18

17

P0.3

P0.2

P0.1

DGND

VDD

P0.0

VDD

DGND

27 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 4.6. LQFP-32 Package Drawing

IDENTIFIER

32

PIN 1

1

A2

D

D1

A1

eb

MIN

NOM

(mm)

A

A1

0.05

E1

E

A2

b

1.35

0.30

D

D1

e

A

E

E1

(mm)

-

1.40

0.37

-

9.00

-

7.00

-

0.80

-

9.00

-

7.00

MAX

(mm)

-

-

1.60

0.15

1.45

0.45

-

-

-

-

-

Rev. 1.7 28

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

5. ADC (12-Bit, C8051F000/1/2/5/6/7 Only)

The ADC subsystem for the C8051F000/1/2/5/6/7 consists of a 9-channel, configurable analog multiplexer
(AMUX), a programmable gain amplifier (PGA), and a 100ksps, 12-bit successive-approximation-register ADC
with integrated track-and-hold and programmable window detector (see block diagram in Figure 5.1). The AMUX,
PGA, Data Conversion Modes, and Window Detector are all configurable under software control via the Special
Function Register’s shown in Figure 5.1. The ADC subsystem (ADC, track-and-hold and PGA) is enabled only
when the ADCEN bit in the ADC Control register (ADC0CN, Figure 5.7) is set to 1. The ADC subsystem is in low
power shutdown when this bit is 0. The Bias Enable bit (BIASE) in the REF0CN register (see Figure 9.2) must be
set to 1 in order to supply bias to the ADC.

Figure 5.1. 12-Bit ADC Functional Block Diagram

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

+

-

+

-

+

-

+

-

9-to-1

AMUX

(SE or

DIFF)

X

+

-

ADCEN

AV+

AGND

12-Bit

SAR

ADC0LTLADC0LTHADC0GTLADC0GTH

AV+

ADC

SYSCLK

REF

12

24

COMB
LOGIC

12

ADC0LADC0H

Conversion Start

ADWINT

TEMP

SENSOR

AGND

M

T

T

CNV

D

A

R
2

B

3
O

STR

U

O
V

SY(

V

w

)

AMX0CF

AIN01IC

AIN23IC

AIN45IC

AIN67IC

AMX0SL

AMXAD1

AMXAD2

AMXAD3

AMXAD0

ADCSC0

ADCSC1

ADCSC2

ADC0CF

AMPGN2

AMPGN1

AMPGN0

ADCEN

ADCTM

ADCINT

ADC0CN

ADSTM0

ADSTM1

ADBUSY

ADWINT

ADLJST

5.1. Analog Multiplexer and PGA

Eight of the AMUX channels are available for external measurements while the ninth channel is internally
connected to an on-board temperature sensor (temperature transfer function is shown in Figure 5.3). Note that the
PGA gain is applied to the temperature sensor reading. AMUX input pairs can be programmed to operate in either
the differential or single-ended mode. This allows the user to select the best measurement technique for each input
channel, and even accommodates mode changes “on-the-fly”. The AMUX defaults to all single-ended inputs upon
reset. There are two registers associated with the AMUX: the Channel Selection register AMX0SL (Figure 5.5),
and the Configuration register AMX0CF (Figure 5.4). The table in Figure 5.5 shows AMUX functionality by
channel for each possible configuration. The PGA amplifies the AMUX output signal by an amount determined by
the AMPGN2-0 bits in the ADC Configuration register, ADC0CF (Figure 5.6). The PGA can be software­programmed for gains of 0.5, 1, 2, 4, 8 or 16. It defaults to unity gain on reset.

29 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

5.2. ADC Modes of Operation

The ADC uses VREF to determine its full-scale voltage, thus the reference must be properly configured before
performing a conversion (see Section 9). The ADC has a maximum conversion speed of 100ksps. The ADC
conversion clock is derived from the system clock. Conversion clock speed can be reduced by a factor of 2, 4, 8 or
16 via the ADCSC bits in the ADC0CF Register. This is useful to adjust conversion speed to accommodate
different system clock speeds.

A conversion can be initiated in one of four ways, depending on the programmed states of the ADC Start of
Conversion Mode bits (ADSTM1, ADSTM0) in ADC0CN. Conversions may be initiated by:

1. Writing a 1 to the ADBUSY bit of ADC0CN;

2. A Timer 3 overflow (i.e. timed continuous conversions);

3. A rising edge detected on the external ADC convert start signal, CNVSTR;

4. A Timer 2 overflow (i.e. timed continuous conversions).

Writing a 1 to ADBUSY provides software control of the ADC whereby conversions are performed “on-demand”.
During conversion, the ADBUSY bit is set to 1 and restored to 0 when conversion is complete. The falling edge of
ADBUSY triggers an interrupt (when enabled) and sets the ADCINT interrupt flag. Note: When conversions are

performed “on-demand”, the ADCINT flag, not ADBUSY, should be polled to determine when the
conversion has completed. Converted data is available in the ADC data word MSB and LSB registers, ADC0H,

ADC0L. Converted data can be either left or right justified in the ADC0H:ADC0L register pair (see example in
Figure 5.9) depending on the programmed state of the ADLJST bit in the ADC0CN register.

The ADCTM bit in register ADC0CN controls the ADC track-and-hold mode. In its default state, the ADC input is
continuously tracked, except when a conversion is in progress. Setting ADCTM to 1 allows one of four different
low power track-and-hold modes to be specified by states of the ADSTM1-0 bits (also in ADC0CN):

1. Tracking begins with a write of 1 to ADBUSY and lasts for 3 SAR clocks;

2. Tracking starts with an overflow of Timer 3 and lasts for 3 SAR clocks;

3. Tracking is active only when the CNVSTR input is low;

4. Tracking starts with an overflow of Timer 2 and lasts for 3 SAR clocks.

Modes 1, 2 and 4 (above) are useful when the start of conversion is triggered with a software command or when the
ADC is operated continuously. Mode 3 is used when the start of conversion is triggered by external hardware. In
this case, the track-and-hold is in its low power mode at times when the CNVSTR input is high. Tracking can also
be disabled (shutdown) when the entire chip is in low power standby or sleep modes.

Figure 5.2. 12-Bit ADC Track and Conversion Example Timing

(ADSTM[1:0]=10)

Timer2, Timer3 Overflow;

Write 1 to ADBUSY

(ADSTM[1:0]=00, 01, 11)

A. ADC Timing for External Trigger Source

CNVSTR

SAR Clocks

ADCTM=1

ADCTM=0

SAR Clocks

ADCTM=1

SAR Clocks

ADCTM=0

Low Power or

Convert

Track Or Convert

B. ADC Timing for Internal Trigger Sources

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Low Power or

Convert

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Track or Convert

1 2 3 4 5 6 7 8 9 1011 1213141516

Track

Track

Convert Track

Convert

Convert

Convert

Low Power Mode

Track

17 18 19

Low Power Mode

Rev. 1.7 30

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 5.3. Temperature Sensor Transfer Function

0.800

0.700

0.600

0.500

0-50 50 100

(Celsius)

C8051F000/1/2/5/6/7

M

C8051F010/1/2/5/6/7

Figure 5.5. AMX0SL: AMUX Channel Select Register (C8051F00x)

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

0xBB

Bits7-4: UNUSED. Read = 0000b; Write = don’t care
Bits3-0: AMXAD3-0: AMUX Address Bits

0000-1111: ADC Inputs selected per chart below

AMXAD3-0

A

0000

X

0001

0
C

0010

F

0011

B
I

0100

T
S

0101

3

-

0110

0

0111

1000

1001

1010

1011

1100

1101

1110

1111

0000 0001 0010 0011 0100 0101 0110 0111 1xxx

AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7

+(AIN0)

-(AIN1)

AIN0 AIN1

+(AIN0)

-(AIN1)

AIN0 AIN1 AIN2 AIN3

+(AIN0)

-(AIN1)

AIN0 AIN1

+(AIN0)

-(AIN1)

AIN0 AIN1 AIN2 AIN3 AIN4 AIN5

+(AIN0)

-(AIN1)

AIN0 AIN1

+(AIN0)

-(AIN1)

AIN0 AIN1 AIN2 AIN3

+(AIN0)

-(AIN1)

AIN0 AIN1

+(AIN0)

-(AIN1)

AIN2 AIN3 AIN4 AIN5 AIN6 AIN7

+(AIN2)

-(AIN3)

+(AIN2)

-(AIN3)

AIN2 AIN3

+(AIN2)

-(AIN3)

+(AIN2)

-(AIN3)

AIN2 AIN3 AIN4 AIN5

+(AIN2)

-(AIN3)

+(AIN2)

-(AIN3)

AIN2 AIN3

+(AIN2)

-(AIN3)

+(AIN2)

-(AIN3)

AMXAD3 AMXAD2 AMXAD1 AMXAD0

TEMP

SENSOR

TEMP

SENSOR

AIN4 AIN5 AIN6 AIN7

AIN4 AIN5 AIN6 AIN7

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

AIN4 AIN5

AIN4 AIN5

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

AIN6 AIN7

AIN6 AIN7

AIN6 AIN7

AIN6 AIN7

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

00000000

SFR Address:

Rev. 1.7 32

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 5.6. ADC0CF: ADC Configuration Register (C8051F00x)

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

ADCSC2 ADCSC1 ADCSC0 - - AMPGN2 AMPGN1 AMPGN0

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xBC

Bits7-5: ADCSC2-0: ADC SAR Conversion Clock Period Bits

Bits4-3: UNUSED. Read = 00b; Write = don’t care
Bits2-0: AMPGN2-0: ADC Internal Amplifier Gain

000: SAR Conversion Clock = 1 System Clock
001: SAR Conversion Clock = 2 System Clocks
010: SAR Conversion Clock = 4 System Clocks
011: SAR Conversion Clock = 8 System Clocks
1xx: SAR Conversion Clock = 16 Systems Clocks
(Note: the SAR Conversion Clock should be ≤ 2MHz)

000: Gain = 1
001: Gain = 2
010: Gain = 4
011: Gain = 8
10x: Gain = 16
11x: Gain = 0.5

01100000

SFR Address:

33 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 5.7. ADC0CN: ADC Control Register (C8051F00x)

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

ADCEN ADCTM ADCINT ADBUSY ADSTM1 ADSTM0 ADWINT ADLJST 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

Bit7: ADCEN: ADC Enable Bit

Bit6: ADCTM: ADC Track Mode Bit

Bit5: ADCINT: ADC Conversion Complete Interrupt Flag
(Must be cleared by software)
0: ADC has not completed a data conversion since the last time this flag was cleared

Bit4: ADBUSY: ADC Busy Bit
Read

Bits3-2: ADSTM1-0: ADC Start of Conversion Mode Bits

Bit1: ADWINT: ADC Window Compare Interrupt Flag

0: ADC Window Comparison Data match has not occurred
1: ADC Window Comparison Data match occurred
Bit0: ADLJST: ADC Left Justify Data Bit
0: Data in ADC0H:ADC0L Registers is right justified
1: Data in ADC0H:ADC0L Registers is left justified

0: ADC Disabled. ADC is in low power shutdown.
1: ADC Enabled. ADC is active and ready for data conversions.

0: When the ADC is enabled, tracking is always done unless a conversion is in process
1: Tracking Defined by ADSTM1-0 bits
ADSTM1-0:
00: Tracking starts with the write of 1 to ADBUSY and lasts for 3 SAR clocks
01: Tracking started by the overflow of Timer 3 and last for 3 SAR clocks
10: ADC tracks only when CNVSTR input is logic low
11: Tracking started by the overflow of Timer 2 and last for 3 SAR clocks

1: ADC has completed a data conversion

0: ADC Conversion complete or no valid data has been converted since a reset. The falling

edge of ADBUSY generates an interrupt when enabled.
1: ADC Busy converting data
Write
0: No effect
1: Starts ADC Conversion if ADSTM1-0 = 00b

00: ADC conversion started upon every write of 1 to ADBUSY
01: ADC conversions taken on every overflow of Timer 3
10: ADC conversion started upon every rising edge of CNVSTR
11: ADC conversions taken on every overflow of Timer 2

(Must be cleared by software)

(bit addressable)

SFR Address:

0xE8

Rev. 1.7 34

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 5.8. ADC0H: ADC Data Word MSB Register (C8051F00x)

R/W R/W R/W R/W R/W R/W R/W Reset Value

00000000

Bit7 Bit0

0xBF

Bit6 Bit5 Bit4 Bit3 Bit2 Bit1

Bits7-0: ADC Data Word Bits
For ADLJST = 1: Upper 8-bits of the 12-bit ADC Data Word.
For ADLJST = 0: Bits7-4 are the sign extension of Bit3. Bits 3-0 are the upper 4-bits of the

12-bit ADC Data Word.

Figure 5.9. ADC0L: ADC Data Word LSB Register (C8051F00x)

R/W

SFR Address:

R/W R/W

00000000

Bit7 Bit5 Bit3 Bit2 Bit1 Bit0

Bits7-0: ADC Data Word Bits
For ADLJST = 1: Bits7-4 are the lower 4-bits of the 12-bit ADC Data Word. Bits3-0 will

For ADLJST = 0: Bits7-0 are the lower 8-bits of the 12-bit ADC Data Word.

always read 0.

R/W R/W R/W R/W R/W R/W Reset Value

Bit6 Bit4

0xBE

NOTE: Resulting 12-bit ADC Data Word appears in the ADC Data Word Registers as follows:

ADC0H[3:0]:ADC0L[7:0], if ADLJST = 0

(ADC0H[7:4] will be sign extension of ADC0H.3 if a differential reading, otherwise = 0000b)

ADC0H[7:0]:ADC0L[7:4], if ADLJST = 1

(ADC0L[3:0] = 0000b)

EXAMPLE: ADC Data Word Conversion Map, AIN0 Input in Single-Ended Mode

(AMX0CF=0x00, AMX0SL=0x00)

AIN0 – AGND
(Volts)

ADC0H:ADC0L

(ADLJST = 0)

ADC0H:ADC0L

(ADLJST = 1)

REF x (4095/4096) 0x0FFF 0xFFF0
REF x ½ 0x0800 0x8000
REF x (2047/4096) 0x07FF 0x7FF0
0 0x0000 0x0000

EXAMPLE: ADC Data Word Conversion Map, AIN0-AIN1 Differential Input Pair

(AMX0CF=0x01, AMX0SL=0x00)

AIN0 – AIN1 (Volts)

ADC0H:ADC0L

(ADLJST = 0)

ADC0H:ADC0L

(ADLJST = 1)

REF x (2047/2048) 0x07FF 0x7FF0
0 0x0000 0x0000

-REF x (1/2048) 0xFFFF 0xFFF0

-REF 0xF800 0x8000

SFR Address:

35 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

5.3. ADC Programmable Window Detector

The ADC programmable window detector is very useful in many applications. It continuously compares the ADC
output to user-programmed limits and notifies the system when an out-of-band 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 (ADWINT in ADC0CN) can also be used in polled
mode. The high and low bytes of the reference words are loaded into the ADC Greater-Than and ADC Less-Than
registers (ADC0GTH, ADC0GTL, ADC0LTH, and ADC0LTL). Figure 5.14 and Figure 5.15 show example
comparisons for reference. Notice that the window detector flag can be asserted when the measured data is inside
or outside the user-programmed limits, depending on the programming of the ADC0GTx and ADC0LTx registers.

Figure 5.10. ADC0GTH: ADC Greater-Than Data High Byte Register (C8051F00x)

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

0xC5

Bits7-0:
The high byte of the ADC Greater-Than Data Word.

SFR Address:

Figure 5.11. ADC0GTL: ADC Greater-Than Data Low Byte Register (C8051F00x)

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

0xC4

Bits7-0:
The low byte of the ADC Greater-Than Data Word.
Definition:
ADC Greater-Than Data Word = ADC0GTH:ADC0GTL

SFR Address:

Figure 5.12. ADC0LTH: ADC Less-Than Data High Byte Register (C8051F00x)

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

0xC7

Bits7-0:
The high byte of the ADC Less-Than Data Word.

SFR Address:

Figure 5.13. ADC0LTL: ADC Less-Than Data Low Byte Register (C8051F00x)

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

0xC6

Bits7-0:
These bits are the low byte of the ADC Less-Than Data Word.
Definition:
ADC Less-Than Data Word = ADC0LTH:ADC0LTL

SFR Address:

Rev. 1.7 36

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 5.14. 12-Bit ADC Window Interrupt Examples, Right Justified Data

Input Voltage

(AD0 - AGND)

REF x (4095/4096)

ADC Data

Word

0x0FFF

REF x (512/4096)

REF x (256/4096)

0x0201

0x0200

0x01FF

0x0101

0x0100

0x00FF

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

ADC0GTH:ADC0GTL

0

0x0000

ADWINT
not affected

Given:
AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 0,
ADC0LTH:ADC0LTL = 0x0200,
ADC0GTH:ADC0GTL = 0x0100.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x0200 and > 0x0100.

Input Voltage

(AD0 - AD1)

REF x (2047/2048)

ADC Data

Word

0x07FF

ADWINT
not affected

REF x (256/2048)

REF x (-1/2048)

0x0101

0x0100

0x00FF

0x0000

0xFFFF

0xFFFE

ADC0LTH:ADC0LTL

ADWINT=1

ADC0GTH:ADC0GTL

-REF

Given:

AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 0,
ADC0LTH:ADC0LTL = 0x0100,
ADC0GTH:ADC0GTL = 0xFFFF.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x0100 and > 0xFFFF. (Two’s
Complement math, 0xFFFF = -1.)

0xF800

ADWINT
not affected

Input Voltage

(AD0 - AGND)

REF x (4095/4096)

REF x (512/4096)

REF x (256/4096)

0

ADC Data

Word

0x0FFF

0x0201

0x0200

0x01FF

0x0101

0x0100

0x00FF

0x0000

ADWINT=1

ADC0GTH:ADC0GTL

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

Given:
AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 0,
ADC0LTH:ADC0LTL = 0x0100,
ADC0GTH:ADC0GTL = 0x0200.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x0100 or > 0x0200.

Input Voltage

(AD0 - AD1)

REF x (2047/2048)

REF x (256/2048)

REF x (-1/2048)

-REF

ADC Data

Word

0x07FF

0x0101

0x0100

0x00FF

0x0000

0xFFFF

0xFFFE

0xF800

ADWINT=1

ADC0GTH:ADC0GTL

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

Given:

AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 0,
ADC0LTH:ADC0LTH = 0xFFFF,
ADC0GTH:ADC0GTL = 0x0100.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0xFFFF or > 0x0100. (Two’s Complement
math, 0xFFFF = -1.)

37 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 5.15. 12-Bit ADC Window Interrupt Examples, Left Justified Data

Input Voltage

(AD0 - AGND)

REF x (4095/4096)

REF x (512/4096)

REF x (256/4096)

ADC Data

Word

0xFFF0

0x2010

0x2000

0x1FF0

0x1010

0x1000

0x0FF0

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

ADC0GTH:ADC0GTL

0

Given:
AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 1,
ADC0LTH:ADC0LTL = 0x2000,
ADC0GTH:ADC0GTL = 0x1000.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x2000 and > 0x1000.

0x0000

ADWINT
not affected

Input Voltage

(AD0 - AD1)

REF x (2047/2048)

ADC Data

Word

0x7FF0

ADWINT
not affected

REF x (256/2048)

REF x (-1/2048)

0x1010

0x1000

0x0FF0

0x0000

0xFFF0

0xFFE0

ADC0LTH:ADC0LTL

ADWINT=1

ADC0GTH:ADC0GTL

-REF

Given:

AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 1,
ADC0LTH:ADC0LTL = 0x1000,
ADC0GTH:ADC0GTL = 0xFFF0.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x1000 and > 0xFFF0. (Two’s
Complement math.)

0x8000

ADWINT
not affected

Input Voltage

(AD0 - AGND)

REF x (4095/4096)

REF x (512/4096)

REF x (256/4096)

0

ADC Data

Word

0xFFF0

0x2010

0x2000

0x1FF0

0x1010

0x1000

0x0FF0

0x0000

ADWINT=1

ADC0GTH:ADC0GTL

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

Given:
AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 1,
ADC0LTH:ADC0LTL = 0x1000,
ADC0GTH:ADC0GTL = 0x2000.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x1000 or > 0x2000.

Input Voltage

(AD0 - AD1)

REF x (2047/2048)

REF x (256/2048)

REF x (-1/2048)

-REF

ADC Data

Word

0x7FF0

0x1010

0x1000

0x0FF0

0x0000

0xFFF0

0xFFE0

0x8000

ADWINT=1

ADC0GTH:ADC0GTL

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

Given:

AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 1,
ADC0LTH:ADC0LTH = 0xFFF0,
ADC0GTH:ADC0GTL = 0x1000.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0xFFF0 or > 0x1000. (Two’s Complement
math.)

Rev. 1.7 38

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 5.1. 12-Bit ADC Electrical Characteristics

VDD = 3.0V, AV+ = 3.0V, VREF = 2.40V (REFBE=0), PGA Gain = 1, -40°C to +85°C unless otherwise specified.

PARAMETER CONDITIONS MIN TYP MAX UNITS

DC ACCURACY

Resolution 12 bits
Integral Nonlinearity
Differential Nonlinearity Guaranteed Monotonic
Offset Error
Full Scale Error Differential mode
Offset Temperature
Coefficient

DYNAMIC PERFORMANCE (10kHz sine-wave input, 0 to –1dB of full scale, 100ksps)

Signal-to-Noise Plus
Distortion
Total Harmonic Distortion Up to the 5th harmonic -75 dB
Spurious-Free Dynamic
Range

CONVERSION RATE

Conversion Time in SAR
Clocks
SAR Clock Frequency C8051F000, ‘F001, ‘F002

Track/Hold Acquisition
Time
Throughput Rate 100 ksps

ANALOG INPUTS

Voltage Conversion Range Single-ended Mode (AINn – AGND)

Input Voltage Any AINn pin AGND AV+ V
Input Capacitance 10 pF

TEMPERATURE SENSOR

Linearity
Absolute Accuracy
Gain PGA Gain = 1 2.86
Gain Error (±1σ)
Offset
Offset Error (±1σ) PGA Gain = 1, Temp = 0°C

POWER SPECIFICATIONS

Power Supply Current (AV+
supplied to ADC)
Power Supply Rejection

66 69 dB

80 dB

16 clocks

C8051F005, ‘F006, ‘F007

1.5

0 VREF

Differential Mode |(AINn+) – (AINm-)|

PGA Gain = 1
PGA Gain = 1, Temp = 0°C

Operating Mode, 100ksps 450 900

-3 ± 1

-7 ± 3

± 0.25

2.0

± 0.20

± 3

± 33.5

776 mV

± 8.51

± 0.3

± 1
± 1

LSB
LSB

2.5

- 1LSB

mV

mV/V

LSB
LSB

ppm/°C

MHz
MHz

µs

V

°C
°C

mV/°C

µV/°C

µA

39 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

6. ADC (10-Bit, C8051F010/1/2/5/6/7 Only)

The ADC subsystem for the C8051F010/1/2/5/6/7 consists of a 9-channel, configurable analog multiplexer
(AMUX), a programmable gain amplifier (PGA), and a 100ksps, 10-bit successive-approximation-register ADC
with integrated track-and-hold and programmable window detector (see block diagram in Figure 6.1). The AMUX,
PGA, Data Conversion Modes, and Window Detector are all configurable under software control via the Special
Function Register’s shown in Figure 6.1. The ADC subsystem (ADC, track-and-hold and PGA) is enabled only
when the ADCEN bit in the ADC Control register (ADC0CN, Figure 6.7) is set to 1. The ADC subsystem is in low
power shutdown when this bit is 0. The Bias Enable bit (BIASE) in the REF0CN register (see Figure 9.2) must be
set to 1 in order to supply bias to the ADC.

Figure 6.1. 10-Bit ADC Functional Block Diagram

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

+

-

+

-

+

-

+

-

9-to-1
AMUX
(SE or

DIFF)

X

+

-

ADCEN

AV+

AGND

10-Bit

SAR

TEMP

SENSOR

AGND

AMX0CF

AIN23IC

AIN45IC

AIN67IC

AIN01IC

AMXAD3

AMX0SL

AMXAD0

AMXAD1

AMXAD2

ADCSC0

ADCSC1

ADCSC2

ADC0CF

AMPGN0

AMPGN1

AMPGN2

6.1. Analog Multiplexer and PGA

Eight of the AMUX channels are available for external measurements while the ninth channel is internally
connected to an on-board temperature sensor (temperature transfer function is shown in Figure 6.3). Note that the
PGA gain is applied to the temperature sensor reading. AMUX input pairs can be programmed to operate in either
the differential or single-ended mode. This allows the user to select the best measurement technique for each input
channel, and even accommodates mode changes “on-the-fly”. The AMUX defaults to all single-ended inputs upon
reset. There are two registers associated with the AMUX: the Channel Selection register AMX0SL (Figure 6.5),
and the Configuration register AMX0CF (Figure 6.4). The table in Figure 6.5 shows AMUX functionality by
channel for each possible configuration. The PGA amplifies the AMUX output signal by an amount determined by
the AMPGN2-0 bits in the ADC Configuration register, ADC0CF (Figure 6.6). The PGA can be software­programmed for gains of 0.5, 1, 2, 4, 8 or 16. It defaults to unity gain on reset.

ADC0LTLADC0LTHADC0GTLADC0GTH

AV+

ADC

ADCEN

ADCTM

ADCINT

ADBUSY

ADC0CN

SYSCLK

ADWINT

ADSTM0

ADSTM1

REF

10

Conversion Start

ADLJST

20

10

ADC0LADC0H

COMB
LOGIC

M

T

T

CNV

A

D

ADWINT

R

3

O
V

O

2

R

T

S

B

U

S

Y

V

w

)

(

Rev. 1.7 40

C8051F000/1/2/5/6/7

e

C8051F010/1/2/5/6/7

6.2. ADC Modes of Operation

The ADC uses VREF to determine its full-scale voltage, thus the reference must be properly configured before
performing a conversion (see Section 9). The ADC has a maximum conversion speed of 100ksps. The ADC
conversion clock is derived from the system clock. Conversion clock speed can be reduced by a factor of 2, 4, 8 or
16 via the ADCSC bits in the ADC0CF Register. This is useful to adjust conversion speed to accommodate
different system clock speeds.

A conversion can be initiated in one of four ways, depending on the programmed states of the ADC Start of
Conversion Mode bits (ADSTM1, ADSTM0) in ADC0CN. Conversions may be initiated by:

1. Writing a 1 to the ADBUSY bit of ADC0CN;

2. A Timer 3 overflow (i.e. timed continuous conversions);

3. A rising edge detected on the external ADC convert start signal, CNVSTR;

4. A Timer 2 overflow (i.e. timed continuous conversions).

Writing a 1 to ADBUSY provides software control of the ADC whereby conversions are performed “on-demand”.
During conversion, the ADBUSY bit is set to 1 and restored to 0 when conversion is complete. The falling edge of
ADBUSY triggers an interrupt (when enabled) and sets the ADCINT interrupt flag. Note: When conversions are

performed “on-demand”, the ADCINT flag, not ADBUSY, should be polled to determine when the
conversion has completed. Converted data is available in the ADC data word MSB and LSB registers, ADC0H,

ADC0L. Converted data can be either left or right justified in the ADC0H:ADC0L register pair (see example in
Figure 6.9) depending on the programmed state of the ADLJST bit in the ADC0CN register.

The ADCTM bit in register ADC0CN controls the ADC track-and-hold mode. In its default state, the ADC input is
continuously tracked, except when a conversion is in progress. Setting ADCTM to 1 allows one of four different
low power track-and-hold modes to be specified by states of the ADSTM1-0 bits (also in ADC0CN):

1. Tracking begins with a write of 1 to ADBUSY and lasts for 3 SAR clocks;

2. Tracking starts with an overflow of Timer 3 and lasts for 3 SAR clocks;

3. Tracking is active only when the CNVSTR input is low;

4. Tracking starts with an overflow of Timer 2 and lasts for 3 SAR clocks.

Modes 1, 2 and 4 (above) are useful when the start of conversion is triggered with a software command or when the
ADC is operated continuously. Mode 3 is used when the start of conversion is triggered by external hardware. In
this case, the track-and-hold is in its low power mode at times when the CNVSTR input is high. Tracking can also
be disabled (shutdown) when the entire chip is in low power standby or sleep modes.

Figure 6.2. 10-Bit ADC Track and Conversion Example Timing

(ADSTM[1:0]=10)

Timer2, Timer3 Overflow;

Write 1 to ADBUSY

(ADSTM[1:0]=00, 01, 11)

41 Rev. 1.7

A. ADC Timing for External Trigger Sourc

CNVSTR

SAR Clocks

ADCTM=1

ADCTM=0

SAR Clocks

ADCTM=1

SAR Clocks

ADCTM=0

Low Power or

Convert

Track Or Convert

B. ADC Timing for Internal Trigger Sources

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Low Power or

Convert

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Track or Convert

12345678910111213141516

Track Convert Low Power Mode

Track Convert Low Power Mode

Convert Track

Convert Track

C8051F000/1/2/5/6/7

N

C8051F010/1/2/5/6/7

Figure 6.3. Temperature Sensor Transfer Function

(Volts)

1.000

0.900

0.800

0.700

0.600

0.500

V

= 0.00286(TEMPC) + 0.776

TEMP

for PGA Gain = 1

0-50 50 100

(Celsius)

Figure 6.4. AMX0CF: AMUX Configuration Register (C8051F01x)

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

- - - - AIN67IC AIN45IC AIN23IC AIN01IC 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xBA

Bits7-4: UNUSED. Read = 0000b; Write = don’t care
Bit3: AIN67IC: AIN6, AIN7 Input Pair Configuration Bit

Bit2: AIN45IC: AIN4, AIN5 Input Pair Configuration Bit

Bit1: AIN23IC: AIN2, AIN3 Input Pair Configuration Bit

Bit0: AIN01IC: AIN0, AIN1 Input Pair Configuration Bit

0: AIN6 and AIN7 are independent singled-ended inputs
1: AIN6, AIN7 are (respectively) +, - differential input pair

0: AIN4 and AIN5 are independent singled-ended inputs
1: AIN4, AIN5 are (respectively) +, - differential input pair

0: AIN2 and AIN3 are independent singled-ended inputs
1: AIN2, AIN3 are (respectively) +, - differential input pair

0: AIN0 and AIN1 are independent singled-ended inputs
1: AIN0, AIN1 are (respectively) +, - differential input pair

OTE: The ADC Data Word is in 2’s complement format for channels configured as differential.

SFR Address:

Rev. 1.7 42

C8051F000/1/2/5/6/7

M

C8051F010/1/2/5/6/7

Figure 6.5. AMX0SL: AMUX Channel Select Register (C8051F01x)

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

0xBB

Bits7-4: UNUSED. Read = 0000b; Write = don’t care
Bits3-0: AMXAD3-0: AMUX Address Bits

0000-1111: ADC Inputs selected per chart below

AMXAD3-0

A

0000

X

0001

0
C

0010

F

0011

B
I
T

0100

S

0101

3

-

0110

0

0111

1000

1001

1010

1011

1100

1101

1110

1111

0000 0001 0010 0011 0100 0101 0110 0111 1xxx

AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7

+(AIN0)

-(AIN1)

AIN0 AIN1

+(AIN0)

-(AIN1)

AIN0 AIN1 AIN2 AIN3

+(AIN0)

-(AIN1)

AIN0 AIN1

+(AIN0)

-(AIN1)

AIN0 AIN1 AIN2 AIN3 AIN4 AIN5

+(AIN0)

-(AIN1)

AIN0 AIN1

+(AIN0)

-(AIN1)

AIN0 AIN1 AIN2 AIN3

+(AIN0)

-(AIN1)

AIN0 AIN1

+(AIN0)

-(AIN1)

AIN2 AIN3 AIN4 AIN5 AIN6 AIN7

+(AIN2)

-(AIN3)

+(AIN2)

-(AIN3)

AIN2 AIN3

+(AIN2)

-(AIN3)

+(AIN2)

-(AIN3)

AIN2 AIN3 AIN4 AIN5

+(AIN2)

-(AIN3)

+(AIN2)

-(AIN3)

AIN2 AIN3

+(AIN2)

-(AIN3)

+(AIN2)

-(AIN3)

AMXAD3 AMXAD2 AMXAD1 AMXAD0

TEMP

SENSOR

TEMP

SENSOR

AIN4 AIN5 AIN6 AIN7

AIN4 AIN5 AIN6 AIN7

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

AIN4 AIN5

AIN4 AIN5

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

+(AIN4)

-(AIN5)

AIN6 AIN7

AIN6 AIN7

AIN6 AIN7

AIN6 AIN7

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

+(AIN6)

-(AIN7)

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

TEMP

SENSOR

00000000

SFR Address:

43 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 6.6. ADC0CF: ADC Configuration Register (C8051F01x)

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

ADCSC2 ADCSC1 ADCSC0 - - AMPGN2 AMPGN1 AMPGN0

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xBC

Bits7-5: ADCSC2-0: ADC SAR Conversion Clock Period Bits

Bits4-3: UNUSED. Read = 00b; Write = don’t care
Bits2-0: AMPGN2-0: ADC Internal Amplifier Gain

000: SAR Conversion Clock = 1 System Clock
001: SAR Conversion Clock = 2 System Clocks
010: SAR Conversion Clock = 4 System Clocks
011: SAR Conversion Clock = 8 System Clocks
1xx: SAR Conversion Clock = 16 Systems Clocks
(Note: Conversion clock should be ≤ 2MHz.)

000: Gain = 1
001: Gain = 2
010: Gain = 4
011: Gain = 8
10x: Gain = 16
11x: Gain = 0.5

01100000

SFR Address:

Rev. 1.7 44

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 6.7. ADC0CN: ADC Control Register (C8051F01x)

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

ADCEN ADCTM ADCINT ADBUSY ADSTM1 ADSTM0 ADWINT ADLJST 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

Bit7: ADCEN: ADC Enable Bit

Bit6: ADCTM: ADC Track Mode Bit

Bit5: ADCINT: ADC Conversion Complete Interrupt Flag
(Must be cleared by software)
0: ADC has not completed a data conversion since the last time this flag was cleared

Bit4: ADBUSY: ADC Busy Bit
Read

Bits3-2: ADSTM1-0: ADC Start of Conversion Mode Bits

Bit1: ADWINT: ADC Window Compare Interrupt Flag
(Must be cleared by software)
0: ADC Window Comparison Data match has not occurred
1: ADC Window Comparison Data match occurred
Bit0: ADLJST: ADC Left Justify Data Bit
0: Data in ADC0H:ADC0L Registers is right justified
1: Data in ADC0H:ADC0L Registers is left justified

0: ADC Disabled. ADC is in low power shutdown.
1: ADC Enabled. ADC is active and ready for data conversions.

0: When the ADC is enabled, tracking is always done unless a conversion is in process
1: Tracking Defined by ADSTM1-0 bits
ADSTM1-0:
00: Tracking starts with the write of 1 to ADBUSY and lasts for 3 SAR clocks
01: Tracking started by the overflow of Timer 3 and last for 3 SAR clocks
10: ADC tracks only when CNVSTR input is logic low
11: Tracking started by the overflow of Timer 2 and last for 3 SAR clocks

1: ADC has completed a data conversion

0: ADC Conversion complete or no valid data has been converted since a reset. The falling

edge of ADBUSY generates an interrupt when enabled.
1: ADC Busy converting data
Write
0: No effect
1: Starts ADC Conversion if ADSTM1-0 = 00b

00: ADC conversion started upon every write of 1 to ADBUSY
01: ADC conversions taken on every overflow of Timer 3
10: ADC conversion started upon every rising edge of CNVSTR
11: ADC conversions taken on every overflow of Timer 2

(bit addressable)

SFR Address:

0xE8

45 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 6.8. ADC0H: ADC Data Word MSB Register (C8051F01x)

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

0xBF

Bits7-0: ADC Data Word Bits
For ADLJST = 1: Upper 8-bits of the 10-bit ADC Data Word.
For ADLJST = 0: Bits7-2 are the sign extension of Bit1. Bits 1-0 are the upper 2-bits of the

10-bit ADC Data Word.

SFR Address:

Figure 6.9. ADC0L: ADC Data Word LSB Register (C8051F01x)

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

0xBE

Bits7-0: ADC Data Word Bits
For ADLJST = 1: Bits7-6 are the lower 2-bits of the 10-bit ADC Data Word. Bits5-0 will

For ADLJST = 0: Bits7-0 are the lower 8-bits of the 10-bit ADC Data Word.

always read 0.

NOTE: Resulting 10-bit ADC Data Word appears in the ADC Data Word Registers as follows:

ADC0H[1:0]:ADC0L[7:0], if ADLJST = 0

(ADC0H[7:2] will be sign extension of ADC0H.1 if a differential reading, otherwise = 000000b)

ADC0H[7:0]:ADC0L[7:6], if ADLJST = 1

(ADC0L[5:0] = 000000b)

EXAMPLE: ADC Data Word Conversion Map, AIN0 Input in Single-Ended Mode

(AMX0CF=0x00, AMX0SL=0x00)

AIN0 – AGND
(Volts)

REF x (1023/1024) 0x03FF 0xFFC0
REF x ½ 0x0200 0x8000
REF x (511/1024) 0x01FF 0x7FC0
0 0x0000 0x0000

EXAMPLE: ADC Data Word Conversion Map, AIN0-AIN1 Differential Input Pair

(AMX0CF=0x01, AMX0SL=0x00)

AIN0 – AIN1 (Volts)

REF x (511/512) 0x01FF 0x7FC0
0 0x0000 0x0000

-REF x (1/512) 0xFFFF 0xFFC0

-REF 0xFE00 0x8000

ADC0H:ADC0L

(ADLJST = 0)

ADC0H:ADC0L

(ADLJST = 0)

ADC0H:ADC0L

(ADLJST = 1)

ADC0H:ADC0L

(ADLJST = 1)

SFR Address:

Rev. 1.7 46

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

6.3. ADC Programmable Window Detector

The ADC programmable window detector is very useful in many applications. It continuously compares the ADC
output to user-programmed limits and notifies the system when an out-of-band 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 (ADWINT in ADC0CN) can also be used in polled
mode. The high and low bytes of the reference words are loaded into the ADC Greater-Than and ADC Less-Than
registers (ADC0GTH, ADC0GTL, ADC0LTH, and ADC0LTL). Figure 6.14 and Figure 6.15 show example
comparisons for reference. Notice that the window detector flag can be asserted when the measured data is inside
or outside the user-programmed limits, depending on the programming of the ADC0GTx and ADC0LTx registers.

Figure 6.10. ADC0GTH: ADC Greater-Than Data High Byte Register (C8051F01x)

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

0xC5

Bits7-0:
The high byte of the ADC Greater-Than Data Word.

SFR Address:

Figure 6.11. ADC0GTL: ADC Greater-Than Data Low Byte Register (C8051F01x)

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

0xC4

Bits7-0:
The low byte of the ADC Greater-Than Data Word.
Definition:
ADC Greater-Than Data Word = ADC0GTH:ADC0GTL

SFR Address:

Figure 6.12. ADC0LTH: ADC Less-Than Data High Byte Register (C8051F01x)

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

0xC7

Bits7-0:
The high byte of the ADC Less-Than Data Word.

SFR Address:

Figure 6.13. ADC0LTL: ADC Less-Than Data Low Byte Register (C8051F01x)

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

0xC6

Bits7-0:
These bits are the low byte of the ADC Less-Than Data Word.

Definition:
ADC Less-Than Data Word = ADC0LTH:ADC0LTL

SFR Address:

47 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 6.14. 10-Bit ADC Window Interrupt Examples, Right Justified Data

Input Voltage

(AD0 - AGND)

REF x (1023/1024)

ADC Data

Word

0x03FF

REF x (512/1024)

REF x (256/1024)

0x0201

0x0200

0x01FF

0x0101

0x0100

0x00FF

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

ADC0GTH:ADC0GTL

0

Given:
AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 0,
ADC0LTH:ADC0LTL = 0x0200,
ADC0GTH:ADC0GTL = 0x0100.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x0200 and > 0x0100.

0x0000

ADWINT
not affected

Input Voltage

(AD0 - AD1)

REF x (511/512)

ADC Data

Word

0x01FF

ADWINT
not affected

REF x (256/512)

REF x

(-1/512)

0x0101

0x0100

0x00FF

0x0000

0xFFFF

0xFFFE

ADC0LTH:ADC0LTL

ADWINT=1

ADC0GTH:ADC0GTL

-REF

0xFE00

ADWINT
not affected

Given:

AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 0,
ADC0LTH:ADC0LTL = 0x0100,
ADC0GTH:ADC0GTL = 0xFFFF.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x0100 and > 0xFFFF. (Two’s
Complement math, 0xFFFF = -1.)

Input Voltage

(AD0 - AGND)

REF x (1023/1024)

REF x (512/1024)

REF x (256/1024)

0

ADC Data

Word

0x03FF

0x0201

0x0200

0x01FF

0x0101

0x0100

0x00FF

0x0000

ADWINT=1

ADC0GTH:ADC0GTL

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

Given:
AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 0,
ADC0LTH:ADC0LTL = 0x0100,
ADC0GTH:ADC0GTL = 0x0200.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x0100 or > 0x0200.

Input Voltage

(AD0 - AD1)

REF x (511/512)

REF x (256/512)

REF x (-1/512)

-REF

ADC Data

Word

0x01FF

0x0101

0x0100

0x00FF

0x0000

0xFFFF

0xFFFE

0xFE00

ADWINT=1

ADC0GTH:ADC0GTL

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

Given:

AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 0,
ADC0LTH:ADC0LTH = 0xFFFF,
ADC0GTH:ADC0GTL = 0x0100.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0xFFFF or > 0x0100. (Two’s Complement
math, 0xFFFF = -1.)

Rev. 1.7 48

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 6.15. 10-Bit ADC Window Interrupt Examples, Left Justified Data

Input Voltage

(AD0 - AGND)

REF x (1023/1024)

ADC Data

Word

0xFFC0

REF x (512/1024)

REF x (256/1024)

0x8040

0x8000

0x7FC0

0x4040

0x4000

0x3FC0

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

ADC0GTH:ADC0GTL

0

Given:
AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 1,
ADC0LTH:ADC0LTL = 0x8000,
ADC0GTH:ADC0GTL = 0x4000.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x8000 and > 0x4000.

0x0000

ADWINT
not affected

Input Voltage

(AD0 - AD1)

REF x (511/512)

ADC Data

Word

0x7FC0

ADWINT
not affected

REF x (128/512)

REF x (-1/512)

0x2040

0x2000

0x1FC0

0x0000

0xFFC0

0xFF80

ADC0LTH:ADC0LTL

ADWINT=1

ADC0GTH:ADC0GTL

-REF

Given:

AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 1,
ADC0LTH:ADC0LTL = 0x2000,
ADC0GTH:ADC0GTL = 0xFFC0.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x2000 and > 0xFFC0. (Two’s
Complement math.)

0x8000

ADWINT
not affected

Input Voltage

(AD0 - AGND)

REF x (1023/1024)

REF x (512/1024)

REF x (256/1024)

0

ADC Data

Word

0xFFC0

0x8040

0x8000

0x7FC0

0x4040

0x4000

0x3FC0

0x0000

ADWINT=1

ADC0GTH:ADC0GTL

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

Given:
AMX0SL = 0x00, AMX0CF = 0x00, ADLJST = 1,
ADC0LTH:ADC0LTL = 0x4000,
ADC0GTH:ADC0GTL = 0x8000.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0x4000 or > 0x8000.

Input Voltage

(AD0 - AD1)

REF x (511/512)

REF x (128/512)

REF x (-1/512)

-REF

ADC Data

Word

0x7FC0

0x2040

0x2000

0x1FC0

0x0000

0xFFC0

0xFF80

0x8000

ADWINT=1

ADC0GTH:ADC0GTL

ADWINT
not affected

ADC0LTH:ADC0LTL

ADWINT=1

Given:

AMX0SL = 0x00, AMX0CF = 0x01, ADLJST = 1,
ADC0LTH:ADC0LTH = 0xFFC0,
ADC0GTH:ADC0GTL = 0x2000.

An ADC End of Conversion will cause an ADC Window
Compare Interrupt (ADWINT=1) if the resulting ADC
Data Word is < 0xFFC0 or > 0x2000. (Two’s Complement
math.)

49 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 6.1. 10-Bit ADC Electrical Characteristics

VDD = 3.0V, AV+ = 3.0V, VREF = 2.40V (REFBE=0), PGA Gain = 1, -40°C to +85°C unless otherwise specified.

PARAMETER CONDITIONS MIN TYP MAX UNITS

DC ACCURACY

Resolution 10 bits
Integral Nonlinearity
Differential Nonlinearity Guaranteed Monotonic
Offset Error
Full Scale Error Differential mode

Offset Temperature
Coefficient

DYNAMIC PERFORMANCE (10kHz sine-wave input, 0 to –1dB of full scale, 100ksps)

Signal-to-Noise Plus
Distortion
Total Harmonic Distortion Up to the 5th harmonic -70 dB
Spurious-Free Dynamic
Range

CONVERSION RATE

Conversion Time in SAR
Clocks
SAR Clock Frequency C8051F000, ‘F001, ‘F002

Track/Hold Acquisition
Time
Throughput Rate 100 ksps

ANALOG INPUTS

Voltage Conversion Range Single-ended Mode (AINn – AGND)

Input Voltage Any AINn pin AGND AV+ V
Input Capacitance 10 pF

TEMPERATURE SENSOR

Linearity
Absolute Accuracy
Gain PGA Gain = 1 2.86
Gain Error (±1σ)
Offset
Offset Error (±1σ) PGA Gain = 1, Temp = 0°C

POWER SPECIFICATIONS

Power Supply Current (AV+
supplied to ADC)
Power Supply Rejection

59 61 dB

80 dB

16 clocks

2.0

C8051F005, ‘F006, ‘F007

1.5

0 VREF

Differential Mode |(AINn+) – (AINm-)|

PGA Gain = 1
PGA Gain = 1, Temp = 0°C

Operating Mode, 100ksps 450 900

776 mV

± ½ ± 1
± ½ ± 1

± 0.5

-1.5 ±

0.5

± 0.25

- 1LSB

± 0.20

± 3

± 33.5

± 8.51

± 0.3

LSB
LSB

2.5

mV

mV/V

LSB
LSB

ppm/°C

MHz
MHz

µs

V

°C
°C

mV/°C

µV/°C

µA

Rev. 1.7 50

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

7. DACs, 12 BIT VOLTAGE MODE

The C8051F000 MCU family has two 12-bit voltage-mode Digital to Analog Converters. Each DAC has an output
swing of 0V to VREF-1LSB for a corresponding input code range of 0x000 to 0xFFF. Using DAC0 as an example,
the 12-bit data word is written to the low byte (DAC0L) and high byte (DAC0H) data registers. Data is latched into
DAC0 after a write to the corresponding DAC0H register, so the write sequence should be DAC0L followed by
DAC0H if the full 12-bit resolution is required. The DAC can be used in 8-bit mode by initializing DAC0L to the
desired value (typically 0x00), and writing data to only DAC0H with the data shifted to the left. DAC0 Control
Register (DAC0CN) provides a means to enable/disable DAC0 and to modify its input data formatting.

The DAC0 enable/disable function is controlled by the DAC0EN bit (DAC0CN.7). Writing a 1 to DAC0EN
enables DAC0 while writing a 0 to DAC0EN disables DAC0. While disabled, the output of DAC0 is maintained in
a high-impedance state, and the DAC0 supply current falls to 1µA or less. Also, the Bias Enable bit (BIASE) in the
REF0CN register (see Figure 9.2) must be set to 1 in order to supply bias to DAC0. The voltage reference for
DAC0 must also be set properly (see Section 9).

In some instances, input data should be shifted prior to a DAC0 write operation to properly justify data within the
DAC input registers. This action would typically require one or more load and shift operations, adding software
overhead and slowing DAC throughput. To alleviate this problem, the data-formatting feature provides a means for
the user to program the orientation of the DAC0 data word within data registers DAC0H and DAC0L. The three
DAC0DF bits (DAC0CN.[2:0]) allow the user to specify one of five data word orientations as shown in the
DAC0CN register definition.

DAC1 is functionally the same as DAC0 described above. The electrical specifications for both DAC0 and DAC1
are given in Table 7.1.

Figure 7.1. DAC Functional Block Diagram

DAC0EN

DAC0DF2

DAC0CN

DAC0DF1
DAC0DF0

DAC1EN

DAC1DF2

DAC1CN

DAC1DF1
DAC1DF0

DAC0HDAC0L

8

DAC1HDAC1L

8

REF

8

8

12

Dig. MUX

12

Dig. MUX

DAC0

REF

DAC1

+

-

AGND

+

-

AGND

AV+

DAC0

AV+

DAC1

51 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 7.2. DAC0H: DAC0 High Byte Register

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xD3

Bits7-0: DAC0 Data Word Most Significant Byte.

SFR Address:

Figure 7.3. DAC0L: DAC0 Low Byte Register

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xD2

Bits7-0: DAC0 Data Word Least Significant Byte.

SFR Address:

Figure 7.4. DAC0CN: DAC0 Control Register

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

DAC0EN

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xD4

Bit7: DAC0EN: DAC0 Enable Bit

Bits6-3: UNUSED. Read = 0000b; Write = don’t care
Bits2-0: DAC0DF2-0: DAC0 Data Format Bits

0: DAC0 Disabled. DAC0 Output pin is disabled; DAC0 is in low power shutdown mode.
1: DAC0 Enabled. DAC0 Output is pin active; DAC0 is operational.

000: The most significant nybble of the DAC0 Data Word is in DAC0H[3:0], while the least significant

MSB LSB

001: The most significant 5-bits of the DAC0 Data Word is in DAC0H[4:0], while the least significant

MSB LSB

- - - -

byte is in DAC0L.

DAC0H DAC0L

7-bits is in DAC0L[7:1].

DAC0H DAC0L

010: The most significant 6-bits of the DAC0 Data Word is in DAC0H[5:0], while the least significant

6-bits is in DAC0L[7:2].

DAC0H DAC0L

MSB LSB

011: The most significant 7-bits of the DAC0 Data Word is in DAC0H[6:0], while the least significant

5-bits is in DAC0L[7:3].

DAC0H DAC0L

MSB LSB

1xx: The most significant byte of the DAC0 Data Word is in DAC0H, while the least significant nybble

is in DAC0L[7:4].

DAC0H DAC0L

MSB LSB

DAC0DF2 DAC0DF1 DAC0DF0

00000000

SFR Address:

Rev. 1.7 52

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 7.5. DAC1H: DAC1 High Byte Register

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xD6

Bits7-0: DAC1 Data Word Most Significant Byte.

Figure 7.6. DAC1L: DAC1 Low Byte Register

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xD5

Bits7-0: DAC1 Data Word Least Significant Byte.

Figure 7.7. DAC1CN: DAC1 Control Register

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

DAC1EN - - - - DAC1DF2 DAC1DF1 DAC1DF0

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xD7

Bit7: DAC1EN: DAC1 Enable Bit

Bits6-3: UNUSED. Read = 0000b; Write = don’t care
Bits2-0: DAC1DF2-0: DAC1 Data Format Bits

0: DAC1 Disabled. DAC1 Output pin is disabled; DAC1 is in low power shutdown mode.
1: DAC1 Enabled. DAC1 Output is pin active; DAC1 is operational.

000: The most significant nybble of the DAC1 Data Word is in DAC1H[3:0], while the least

significant byte is in DAC1L.

MSB LSB

001: The most significant 5-bits of the DAC1 Data Word is in DAC1H[4:0], while the least

significant 7-bits is in DAC1L[7:1].

DAC1H DAC1L

DAC1H DAC1L

MSB LSB

010: The most significant 6-bits of the DAC1 Data Word is in DAC1H[5:0], while the least

significant 6-bits is in DAC1L[7:2].

DAC1H DAC1L

MSB LSB

011: The most significant 7-bits of the DAC1 Data Word is in DAC1H[6:0], while the least

significant 5-bits is in DAC1L[7:3].

DAC1H DAC1L

MSB LSB

1xx: The most significant byte of the DAC1 Data Word is in DAC1H, while the least

significant nybble is in DAC1L[7:4].

DAC1H DAC1L

MSB LSB

SFR Address:

SFR Address:

00000000

SFR Address:

53 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 7.1. DAC Electrical Characteristics

VDD = 3.0V, AV+ = 3.0V, REF = 2.40V (REFBE=0), No Output Load unless otherwise specified.

PARAMETER CONDITIONS MIN TYP MAX UNITS

STATIC PERFORMANCE

Resolution 12 bits
Integral Nonlinearity For Data Word Range 0x014 to 0xFEB
Differential Nonlinearity Guaranteed Monotonic (codes 0x014 to

0xFEB)

Output Noise No Output Filter

100kHz Output Filter

10kHz Output Filter
Offset Error Data Word = 0x014
Offset Tempco 6
Full-Scale Error
Full-Scale Error Tempco 10

VDD Power-Supply
Rejection Ratio

Output Impedance in
Shutdown Mode

Output Current

Output Short Circuit Current

DYNAMIC PERFORMANCE

Voltage Output Slew Rate Load = 40pF 0.44
Output Settling Time To ½

LSB
Output Voltage Swing 0 REF-

Startup Time DAC Enable asserted 10

ANALOG OUTPUTS

Load Regulation IL = 0.01mA to 0.3mA at code 0xFFF

CURRENT CONSUMPTION (each DAC)

Power Supply Current (AV+
supplied to DAC)

-60 dB

DACnEN=0 100

Data Word = 0xFFF 15 mA

Load = 40pF, Output swing from code

0xFFF to 0x014

Data Word = 0x7FF 110 400

250

10

60 ppm

±2

128

41

±3 ±30

±20 ±60

±300

LSB

±1

1LSB

LSB

µVrms

mV

ppm/°C

mV

ppm/°C

kΩ

µA

V/µs

µs

V

µs

µA

Rev. 1.7 54

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

8. COMPARATORS

The MCU family has two on-chip analog voltage comparators as shown in Figure 8.1. The inputs of each
Comparator are available at the package pins. The output of each comparator is optionally available at the package
pins via the I/O crossbar (see Section 15.1). When assigned to package pins, each comparator output can be
programmed to operate in open drain or push-pull modes (see section 15.3).

The hysteresis of each comparator is software-programmable via its respective Comparator control register
(CPT0CN, CPT1CN). 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 output of the
comparator can be polled in software, or can be used as an interrupt source. Each comparator can be individually
enabled or disabled (shutdown). When disabled, the comparator output (if assigned to a Port I/O pin via the
Crossbar) defaults to the logic low state, its interrupt capability is suspended and its supply current falls to less than
1µA. Comparator 0 inputs can be externally driven from -0.25V to (AV+) + 0.25V without damage or upset.

The Comparator 0 hysteresis is programmed using bits 3-0 in the Comparator 0 Control Register CPT0CN (shown
in Figure 8.3). The amount of negative hysteresis voltage is determined by the settings of the CP0HYN bits. As
shown in Figure 8.2, settings of 10, 4 or 2mV of negative hysteresis can be programmed, or negative hysteresis can
be disabled. In a similar way, the amount of positive hysteresis is determined by the setting the CP0HYP bits.

Comparator interrupts can be generated on both rising-edge and falling-edge output transitions. (For Interrupt
enable and priority control, see Section 10.4). The CP0FIF flag is set upon a Comparator 0 falling-edge interrupt,
and the CP0RIF flag is set upon the Comparator 0 rising-edge interrupt. Once set, these bits remain set until cleared
by the CPU. The Output State of Comparator 0 can be obtained at any time by reading the CP0OUT bit. Note the
comparator output and interrupt should be ignored until the comparator settles after power-up. Comparator 0 is
enabled by setting the CP0EN bit, and is disabled by clearing this bit. Note there is a 20usec settling time for the
comparator output to stabilize after setting the CP0EN bit or a power-up. Comparator 0 can also be programmed as
a reset source. For details, see Section 13.

The operation of Comparator 1 is identical to that of Comparator 0, except the Comparator 1 is controlled by the
CPT1CN Register (Figure 8.4). Comparator 1 can not be programmed as a reset source. Also, the input pins for
Comparator 1 are not pinned out on the F002, F007, F012, or F017 devices. The complete electrical specifications
for the Comparators are given in Table 8.1.

Figure 8.1. Comparator Functional Block Diagram

CPT0CN

CPT1CN

CP0EN

CP0OUT

CP0RIF

CP0FIF

CP0HYP1

CP0HYP0

CP0HYN1

CP0HYN0

CP1EN

CP1OUT

CP1RIF

CP1FIF

CP1HYP1

CP1HYP0

CP1HYN1

CP1HYN0

AV+

Reset

Decision

+

-

AGND

AV+

+

-

AGND

Tree

SET

SET

Q

D

D

Q

CLR

CLR

(SYNCHRONIZER)

SET

SET

Q

D

D

Q

CLR

CLR

(SYNCHRONIZER)

Q

Crossbar

Q

Interrupt

Handler

Q

Crossbar

Q

Interrupt

Handler

CP0+

CP0-

CP1+

CP1-

not available on F002,

F007, F012, and F017

55 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 8.2. Comparator Hysteresis Plot

VIN+

CP0+

CP0-

VIN-

CIRCUIT CONFIGURATION

Positive Hysteresis Voltage

(Programmed with CP0HYSP Bits)

INPUTS

VIN-

VIN+

OUTPUT

V

OL

Positive Hysteresis

Disabled

+

CP0

_

V

OH

OUT

Maximum

Positive Hysteresis

Negative Hysteresis

Disabled

Negative Hysteresis Voltage

(Programmed by CP0HYSN Bits)

Maximum

Negative Hysteresis

Rev. 1.7 56

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 8.3. CPT0CN: Comparator 0 Control Register

R/W R R/W R/W R/W R/W R/W R/W Reset Value

CP0EN CP0OUT CP0RIF CP0FIF CP0HYP1 CP0HYP0 CP0HYN1 CP0HYN0 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

Bit7: CP0EN: Comparator 0 Enable Bit

Bit6: CP0OUT: Comparator 0 Output State Flag

Bit5: CP0RIF: Comparator 0 Rising-Edge Interrupt Flag

1: Comparator 0 Rising-Edge Interrupt has occurred since this flag was cleared
Bit4: CP0FIF: Comparator 0 Falling-Edge Interrupt Flag

1: Comparator 0 Falling-Edge Interrupt has occurred since this flag was cleared
Bit3-2: CP0HYP1-0: Comparator 0 Positive Hysteresis Control Bits

Bit1-0: CP0HYN1-0: Comparator 0 Negative Hysteresis Control Bits

0: Comparator 0 Disabled.
1: Comparator 0 Enabled.

0: Voltage on CP0+ < CP0-
1: Voltage on CP0+ > CP0-

0: No Comparator 0 Rising-Edge Interrupt has occurred since this flag was cleared

0: No Comparator 0 Falling-Edge Interrupt has occurred since this flag was cleared

00: Positive Hysteresis Disabled
01: Positive Hysteresis = 2mV
10: Positive Hysteresis = 4mV
11: Positive Hysteresis = 10mV

00: Negative Hysteresis Disabled
01: Negative Hysteresis = 2mV
10: Negative Hysteresis = 4mV
11: Negative Hysteresis = 10mV

SFR Address:

0x9E

57 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 8.4. CPT1CN: Comparator 1 Control Register

R/W R R/W R/W R/W R/W R/W R/W Reset Value

CP1EN CP1OUT CP1RIF CP1FIF CP1HYP1 CP1HYP0 CP1HYN1 CP1HYN0 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

Bit7: CP1EN: Comparator 1 Enable Bit

Bit6: CP1OUT: Comparator 1 Output State Flag

Bit5: CP1RIF: Comparator 1 Rising-Edge Interrupt Flag

1: Comparator 1 Rising-Edge Interrupt has occurred since this flag was cleared
Bit4: CP1FIF: Comparator 1 Falling-Edge Interrupt Flag

1: Comparator 1 Falling-Edge Interrupt has occurred since this flag was cleared
Bit3-2: CP1HYP1-0: Comparator 1 Positive Hysteresis Control Bits

Bit1-0: CP1HYN1-0: Comparator 1 Negative Hysteresis Control Bits

0: Comparator 1 Disabled.
1: Comparator 1 Enabled.

0: Voltage on CP1+ < CP1-
1: Voltage on CP1+ > CP1-

0: No Comparator 1 Rising-Edge Interrupt has occurred since this flag was cleared

0: No Comparator 1 Falling-Edge Interrupt has occurred since this flag was cleared

00: Positive Hysteresis Disabled
01: Positive Hysteresis = 2mV
10: Positive Hysteresis = 4mV
11: Positive Hysteresis = 10mV

00: Negative Hysteresis Disabled
01: Negative Hysteresis = 2mV
10: Negative Hysteresis = 4mV
11: Negative Hysteresis = 10mV

SFR Address:

0x9F

Rev. 1.7 58

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 8.1. Comparator Electrical Characteristics

VDD = 3.0V, AV+ = 3.0V, -40°C to +85°C unless otherwise specified.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Response Time1 (CP+) – (CP-) = 100mV (Note 1) 4
Response Time2 (CP+) – (CP-) = 10mV (Note 1) 12
Common Mode Rejection

Ratio
Positive Hysteresis1 CPnHYP1-0 = 00 0 1 mV
Positive Hysteresis2 CPnHYP1-0 = 01 2 4.5 7 mV
Positive Hysteresis3 CPnHYP1-0 = 10 4 9 13 mV
Positive Hysteresis4 CPnHYP1-0 = 11 10 17 25 mV
Negative Hysteresis1 CPnHYN1-0 = 00 0 1 mV
Negative Hysteresis2 CPnHYN1-0 = 01 2 4.5 7 mV
Negative Hysteresis3 CPnHYN1-0 = 10 4 9 13 mV
Negative Hysteresis4 CPnHYN1-0 = 11 10 17 25 mV
Inverting or Non-inverting
Input Voltage Range
Input Capacitance 7 pF
Input Bias Current -5 0.001 +5 nA
Input Offset Voltage -10 +10 mV

POWER SUPPLY

Power-up Time CPnEN from 0 to 1 20
Power Supply Rejection 0.1 1 mV/V
Supply Current Operating Mode (each comparator) at DC 1.5 10

Note 1: CPnHYP1-0 = CPnHYN1-0 = 00.

1.5 4 mV/V

-0.25 (AV+)
+ 0.25

µs
µs

V

µs

µA

59 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

9. VOLTAGE REFERENCE

The voltage reference circuit consists of a 1.2V, 15ppm/°C (typical) bandgap voltage reference generator and a
gain-of-two output buffer amplifier. The reference voltage on VREF can be connected to external devices in the
system, as long as the maximum load seen by the VREF pin is less than 200µA to AGND (see Figure 9.1).

If a different reference voltage is required, an external reference can be connected to the VREF pin and the internal
bandgap and buffer amplifier disabled in software. The external reference voltage must still be less than AV+ -

0.3V. The Reference Control Register, REF0CN (defined in Figure 9.2), provides the means to enable or disable
the bandgap and buffer amplifier. The BIASE bit in REF0CN enables the bias circuitry for the ADC and DACs
while the REFBE bit enables the bandgap reference and buffer amplifier which drive the VREF pin. When
disabled, the supply current drawn by the bandgap and buffer amplifier falls to less than 1uA (typical) and the
output of the buffer amplifier enters a high impedance state. If the internal bandgap is used as the reference voltage
generator, BIASE and REFBE must both be set to 1. If an external reference is used, REFBE must be set to 0 and
BIASE must be set to 1. If neither the ADC nor the DAC are being used, both of these bits can be set to 0 to
conserve power. The electrical specifications for the Voltage Reference are given in Table 9.1.

The temperature sensor connects to the highest order input of the A/D converter’s input multiplexer (see Figure 5.1
and Figure 5.5 for details). The TEMPE bit within REF0CN enables and disables the temperature sensor. While
disabled, the temperature sensor defaults to a high impedance state and any A/D measurements performed on the
sensor while disabled result in meaningless data.

External Equivalent

Load Circuit

200uA

(max)

AV+

AGND

AGND

Figure 9.1. Voltage Reference Functional Block Diagram

R1

RLOAD

External

Voltage

Reference

Circuit

VREF

REF0CN

TEMPE

BIASE

REFBE

EN

EN

Bias

Generator

EN

2.4V

Reference

Temp

Sensor

AGND

AGND

(to Analog Mux)

(Bias to ADC
and DAC)

(to ADC
and DAC)

Rev. 1.7 60

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 9.2. REF0CN: Reference Control Register

R/W R/W R/W R/W R/W R/W R/W Reset Value

- - - - - TEMPE BIASE REFBE 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

Bits7-3: UNUSED. Read = 00000b; Write = don’t care
Bit2: TEMPE: Temperature Sensor Enable Bit
0: Internal Temperature Sensor Off.
1: Internal Temperature Sensor On.
Bit1: BIASE: Bias Enable Bit for ADC and DAC’s
0: Internal Bias Off.
1: Internal Bias On (required for use of ADC or DAC’s).
Bit0: REFBE: Internal Voltage Reference Buffer Enable Bit

1: Internal Reference Buffer On. System reference provided by internal voltage reference.

0: Internal Reference Buffer Off. System reference can be driven from external source on

R/W

SFR Address:

0xD1

VREF pin.

Table 9.1. Reference Electrical Characteristics

VDD = 3.0V, AV+ = 3.0V, -40°C to +85°C unless otherwise specified.

PARAMETER

INTERNAL REFERENCE (REFBE = 1)

Output Voltage
VREF Short Circuit Current 30 mA
VREF Power Supply

Current (supplied by AV+)
VREF Temperature
Coefficient
Load Regulation
VREF Turn-on Time1
VREF Turn-on Time2
VREF Turn-on Time3 no bypass cap 10

EXTERNAL REFERENCE (REFBE = 0)

Input Voltage Range 1.00 (AV+)

Input Current 0 1

25°C ambient

50

15

Load = (0-to-200µA) to AGND (Note 1)

4.7µF tantalum, 0.1µF ceramic bypass

0.1µF ceramic bypass

CONDITIONS MIN TYP MAX UNITS

2.34 2.43 2.50 V

µA

ppm/°C

0.5
2 ms
20

– 0.3V

ppm/µA

µs
µs

V

µA

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

10. CIP-51 CPU

The MCUs’ system CPU is the CIP-51. The CIP-51 is fully compatible with the MCS-51TM instruction set.
Standard 803x/805x assemblers and compilers can be used to develop software. The MCU family has a superset of
all the peripherals included with a standard 8051. Included are four 16-bit counter/timers (see description in Section

19), a full-duplex UART (see description in Section 18), 256 bytes of internal RAM, 128 byte Special Function
Register (SFR) address space (see Section 10.3), and four byte-wide I/O Ports (see description in Section 14). The
CIP-51 also includes on-chip debug hardware (see description in Section 21), and interfaces directly with the
MCUs’ analog and digital subsystems providing a complete data acquisition or control-system solution in a single
integrated circuit.

Features

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
includes the following features:

- Fully Compatible with MCS-51 Instruction Set

- 25 MIPS Peak Throughput with 25MHz Clock

- 0 to 25MHz Clock Frequency (on ‘F0x5/6/7)

- Four Byte-Wide I/O Ports

- Extended Interrupt Handler

- Reset Input

- Power Management Modes

- On-chip Debug Circuitry

- Program and Data Memory Security

Figure 10.1. CIP-51 Block Diagram

D8

ACCUMULATOR

D8

TMP1 TMP2

DATA BUS

D8

D8

B REGISTER

D8

STACK POINTER

D8

D8

A16

D8

D8

SRAM
ADDRESS
REGISTER

D8

SFR
BUS

INTERFACE

MEMORY

INTERFACE

INTERRUPT
INTERFACE

SRAM

(256 X 8)

D8

SFR_ADDRESS

SFR_CONTROL

SFR_WRITE_DATA

SFR_READ_DATA

MEM_ADDRESS

MEM_CONTROL

MEM_WRITE_DATA

MEM_READ_DATA

SYSTEM_IRQs

EMULATION_IRQ

DATA BUS

PSW

D8

ALU

D8

DATA BUS

BUFFER

DATA POINTER

PC INCREMENTER

PROGRAM COUNTER (PC)

PRGM. ADDRESS REG.

PIPELINE

REGISTER

RESET

CLOCK

STOP

IDLE

CONTROL

LOGIC

POWER CONTROL

D8

D8

DATA BUS

D8

Rev. 1.7 62

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

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 12MHz. 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 maximum system clock at 25MHz, it has a peak throughput of 25MIPS. The CIP-51 has a total
of 109 instructions. The number of instructions versus the system clock cycles required to execute them is as
follows:

Instructions

Clocks to Execute

Programming and Debugging Support

A JTAG-based serial interface is provided for in-system programming of the Flash program memory and
communication with on-chip debug support circuitry. The reprogrammable Flash can also be read and changed 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 circuitry facilitates full speed in-circuit debugging, allowing the setting of hardware
breakpoints and watch points, 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 and non-invasive, requiring no RAM, Stack, timers,
or other on-chip resources.

The CIP-51 is supported by development tools from Silicon Laboratories and third party vendors. Silicon Labs
provides an integrated development environment (IDE) including editor, macro assembler, debugger and
programmer. The IDE’s debugger and programmer interface to the CIP-51 via its JTAG interface 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 one less clock cycle 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.

10.1.2. MOVX Instruction and Program Memory

The MOVX instruction is typically used to access external data memory. In the CIP-51, the MOVX instruction can
access the on-chip program memory space implemented as reprogrammable Flash memory using the control bits in
the PSCTL register (see Figure 11.1). This feature provides a mechanism for the CIP-51 to update program code
and use the program memory space for non-volatile data storage. For the products with RAM mapped into external
data memory space (C8051F005/06/07/15/16/17), MOVX is still used to read/write this memory with the PSCTL

26 50 5 14 7 3 1 2 1

1 2 2/3 3 3/4 4 4/5 5 8

63 Rev. 1.7

C8051F000/1/2/5/6/7

register configured for accessing the external data memory space. Refer to Section 11 (Flash Memory) for further
details.

C8051F010/1/2/5/6/7

Rev. 1.7 64

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 10.1. CIP-51 Instruction Set Summary

Mnemonic Description Bytes

ARITHMETIC OPERATIONS

ADD A,Rn Add register to A 1 1
ADD A,direct Add direct byte to A 2 2
ADD A,@Ri Add indirect RAM to A 1 2
ADD A,#data Add immediate to A 2 2
ADDC A,Rn Add register to A with carry 1 1
ADDC A,direct Add direct byte to A with carry 2 2
ADDC A,@Ri Add indirect RAM to A with carry 1 2
ADDC A,#data Add immediate to A with carry 2 2
SUBB A,Rn Subtract register from A with borrow 1 1
SUBB A,direct Subtract direct byte from A with borrow 2 2
SUBB A,@Ri Subtract indirect RAM from A with borrow 1 2
SUBB A,#data Subtract immediate from A with borrow 2 2
INC A Increment A 1 1
INC Rn Increment register 1 1
INC direct Increment direct byte 2 2
INC @Ri Increment indirect RAM 1 2
DEC A Decrement A 1 1
DEC Rn Decrement register 1 1
DEC direct Decrement direct byte 2 2
DEC @Ri Decrement indirect RAM 1 2
INC DPTR Increment Data Pointer 1 1
MUL AB Multiply A and B 1 4
DIV AB Divide A by B 1 8
DA A Decimal Adjust A 1 1

LOGICAL OPERATIONS

ANL A,Rn AND Register to A 1 1
ANL A,direct AND direct byte to A 2 2
ANL A,@Ri AND indirect RAM to A 1 2
ANL A,#data AND immediate to A 2 2
ANL direct,A AND A to direct byte 2 2
ANL direct,#data AND immediate to direct byte 3 3
ORL A,Rn OR Register to A 1 1
ORL A,direct OR direct byte to A 2 2
ORL A,@Ri OR indirect RAM to A 1 2
ORL A,#data OR immediate to A 2 2
ORL direct,A OR A to direct byte 2 2
ORL direct,#data OR immediate to direct byte 3 3
XRL A,Rn Exclusive-OR Register to A 1 1
XRL A,direct Exclusive-OR direct byte to A 2 2
XRL A,@Ri Exclusive-OR indirect RAM to A 1 2
XRL A,#data Exclusive-OR immediate to A 2 2
XRL direct,A Exclusive-OR A to direct byte 2 2
XRL direct,#data Exclusive-OR immediate to direct byte 3 3
CLR A Clear A 1 1
CPL A Complement A 1 1
RL A Rotate A left 1 1
RLC A Rotate A left through carry 1 1
RR A Rotate A right 1 1

Clock

Cycles

65 Rev. 1.7

C8051F000/1/2/5/6/7

Mnemonic Description Bytes

RRC A Rotate A right through carry 1 1
SWAP A Swap nibbles of A 1 1

DATA TRANSFER

MOV A,Rn Move register to A 1 1
MOV A,direct Move direct byte to A 2 2
MOV A,@Ri Move indirect RAM to A 1 2
MOV A,#data Move immediate to A 2 2
MOV Rn,A Move A to register 1 1
MOV Rn,direct Move direct byte to register 2 2
MOV Rn,#data Move immediate to register 2 2
MOV direct,A Move A to direct byte 2 2
MOV direct,Rn Move register to direct byte 2 2
MOV direct,direct Move direct byte to direct 3 3
MOV direct,@Ri Move indirect RAM to direct byte 2 2
MOV direct,#data Move immediate to direct byte 3 3
MOV @Ri,A Move A to indirect RAM 1 2
MOV @Ri,direct Move direct byte to indirect RAM 2 2
MOV @Ri,#data Move immediate to indirect RAM 2 2
MOV DPTR,#data16 Load data pointer with 16-bit constant 3 3
MOVC A,@A+DPTR Move code byte relative DPTR to A 1 3
MOVC A,@A+PC Move code byte relative PC to A 1 3
MOVX A,@Ri Move external data (8-bit address) to A 1 3
MOVX @Ri,A Move A to external data (8-bit address) 1 3
MOVX A,@DPTR Move external data (16-bit address) to A 1 3
MOVX @DPTR,A Move A to external data (16-bit address) 1 3
PUSH direct Push direct byte onto stack 2 2
POP direct Pop direct byte from stack 2 2
XCH A,Rn Exchange register with A 1 1
XCH A,direct Exchange direct byte with A 2 2
XCH A,@Ri Exchange indirect RAM with A 1 2
XCHD A,@Ri Exchange low nibble of indirect RAM with A 1 2

BOOLEAN MANIPULATION

CLR C Clear carry 1 1
CLR bit Clear direct bit 2 2
SETB C Set carry 1 1
SETB bit Set direct bit 2 2
CPL C Complement carry 1 1
CPL bit Complement direct bit 2 2
ANL C,bit AND direct bit to carry 2 2
ANL C,/bit AND complement of direct bit to carry 2 2
ORL C,bit OR direct bit to carry 2 2
ORL C,/bit OR complement of direct bit to carry 2 2
MOV C,bit Move direct bit to carry 2 2
MOV bit,C Move carry to direct bit 2 2
JC rel Jump if carry is set 2 2/3
JNC rel Jump if carry not set 2 2/3
JB bit,rel Jump if direct bit is set 3 3/4
JNB bit,rel Jump if direct bit is not set 3
JBC bit,rel Jump if direct bit is set and clear bit 3 3/4

PROGRAM BRANCHING

C8051F010/1/2/5/6/7

Clock

Cycles

3/4

Rev. 1.7 66

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Mnemonic Description Bytes

Clock

Cycles

ACALL addr11 Absolute subroutine call 2 3
LCALL addr16 Long subroutine call 3 4
RET Return from subroutine 1 5
RETI Return from interrupt 1 5
AJMP addr11 Absolute jump 2 3

LJMP addr16 Long jump 3 4
SJMP rel Short jump (relative address) 2 3
JMP @A+DPTR

Jump indirect relative to DPTR 1 3
JZ rel Jump if A equals zero 2 2/3
JNZ rel Jump if A does not equal zero 2 2/3
CJNE A,direct,rel Compare direct byte to A and jump if not equal 3 3/4
CJNE A,#data,rel Compare immediate to A and jump if not equal 3 3/4

CJNE Rn,#data,rel

Compare immediate to register and jump if not

3 3/4

equal
CJNE @Ri,#data,rel Compare immediate to indirect and jump if not

3 4/5

equal
DJNZ Rn,rel Decrement register and jump if not zero 2 2/3
DJNZ direct,rel Decrement direct byte and jump if not zero 3 3/4
NOP No operation 1 1

Notes on Registers, Operands and Addressing Modes:

Rn - Register R0-R7 of the currently selected register bank.

@Ri - Data RAM location addressed indirectly through register R0-R1

rel - 8-bit, signed (two’s compliment) offset relative to the first byte of the following instruction. Used by SJMP

and all conditional jumps.

direct - 8-bit internal data location’s address. This could be a direct-access Data RAM location (0x00-0x7F) or an
SFR (0x80-0xFF).

#data - 8-bit constant

#data 16 - 16-bit constant

bit - Direct-addressed bit in Data RAM or SFR.

addr 11 - 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.

addr 16 - 16-bit destination address used by LCALL and LJMP. The destination may be anywhere within the
64K-byte program memory space.

There is one unused opcode (0xA5) that performs the same function as NOP.
All mnemonics copyrighted © Intel Corporation 1980.

67 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

10.2. MEMORY ORGANIZATION

The memory organization of the CIP-51 System Controller 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. There are 256 bytes of internal data memory and 64K bytes of
internal program memory address space implemented within the CIP-51. The CIP-51 memory organization is
shown in Figure 10.2.

10.2.1. Program Memory

The CIP-51 has a 64K-byte program memory space. The MCU implements 32896 bytes of this program memory
space as in-system, reprogrammable Flash memory, organized in a contiguous block from addresses 0x0000 to
0x807F. Note: 512 bytes (0x7E00 – 0x7FFF) of this memory are reserved for factory use and are not available for
user program storage.

Program memory is normally assumed to be read-only. However, the CIP-51 can write to program memory by
setting the Program Store Write Enable bit (PSCTL.0) and using the MOVX instruction. This 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 11 (Flash Memory) for further details.

10.2.2. Data Memory

The CIP-51 implements 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 be addressed as bytes or as 128 bit locations accessible with the direct­bit 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 (SFR) 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 will access the upper 128 bytes of data memory. Figure
10

.2 illustrates the data memory organization of the CIP-51.

The C8051F005/06/07/15/16/17 also have 2048 bytes of RAM in the external data memory space of the CIP-51,
accessible using the MOVX instruction. Refer to Section 12 (External RAM) for details.

10.2.3. General Purpose Registers

The lower 32 bytes of data memory, locations 0x00 through 0x1F, may be addressed as four banks of general­purpose 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 Figure 1 .6). This allows fast context switching when entering
subroutines and interrupt service routines. Indirect addressing modes use registers R0 and R1 as index registers.

10.2.4. 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, 22h.3

moves the Boolean value at 0x13 (bit 3 of the byte at location 0x22) into the user Carry flag.

0

Rev. 1.7 68

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 10.2. Memory Map

0x807F

0x8000

0x7FFF

0x7E00

0x7DFF

0x0000

PROGRAM MEMORY

128 Byte ISP FLASH

RESERVED

FLASH

(In-System

Programmable in 512

Byte Sectors)

0xFF

0x80
0x7F

0x30
0x2F

0x20
0x1F

0x00

0xFFFF

0xF800

0x17FF

0x1000

0x0FFF

0x0800

0x07FF

0x0000

DATA MEMORY

INTERNAL DATA ADDRESS SPACE

Upper 128 RAM

(Indirect Addressing

Only)

(Direct and Indirect

Addressing)

Bit Addressable

General Purpose

Registers

Special Function

Register's

(Direct Addressing Only)

Lower 128 RAM
(Direct and Indirect
Addressing)

EXTERNAL DATA ADDRESS SPACE

(same 2048 byte RAM block )

The same 2048 byte RAM

(same 2048 byte RAM block )

(same 2048 byte RAM block )

block can be addressed on
2k boundaries throughout
the 64k External Data
Memory space.

RAM - 2048 Bytes

(accessable using MOVX

command)

10.2.5. 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.

The MCUs also have built-in hardware for a stack record. The stack record is a 32-bit shift register, where each
Push or increment SP pushes one record bit onto the register, and each Call or interrupt pushes two record bits onto
the register. (A Pop or decrement SP pops one record bit, and a Return pops two record bits, also.) The stack
record circuitry can also detect an overflow or underflow on the Stack, and can notify the debug software even with
the MCU running full-speed debug.

69 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

10.3. SPECIAL FUNCTION REGISTERS

The direct-access data memory locations from 0x80 to 0xFF constitute the special function registers (SFRs). The
SFRs provide control and data exchange with the CIP-51’s resources and peripherals. The CIP-51 duplicates the
SFRs found in a typical 8051 implementation as well as implementing additional SFRs used to configure and access
the sub-systems unique to the MCU. This allows the addition of new functionality while retaining compatibility
with the MCS-51™ instruction set. Table 10.3 lists the SFRs implemented in the CIP-51 System Controller.

The SFR registers are accessed any time 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, P1, SCON, 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 datasheet, as indicated in Table 10.3, for a detailed description of each register.

Table 10.2. Special Function Register Memory Map

SPI0CN PCA0CPH3

F8

B EIP1 EIP2

F0

ADC0CN PCA0L PCA0CPL0 PCA0CPL1 PCA0CPL2 PCA0CPL3 PCA0CPL4 RSTSRC

E8

ACC XBR0 XBR1 XBR2 EIE2 EIE1

E0
D8
D0

A8
A0

PCA0CN

PSW REF0CN DAC0L DAC0H DAC0CN DAC1L DAC1H DAC1CN

T2CON RCAP2L RCAP2H TL2 TH2 SMB0CR

C8

SMB0CN SMB0STA

C0

IP AMX0CF ADC0CF ADC0L ADC0H

B8

P3 OSCXCN OSCICN FLSCL FLACL***

B0

IE PRT1IF EMI0CN***

P2 PRT0CF PRT1CF PRT2CF PRT3CF

SCON SBUF SPI0CFG SPI0DAT SPI0CKR CPT0CN CPT1CN

98

P1 TMR3CN TMR3RLL TMR3RLH TMR3H TMR3L

90

TCON PSCTL TMOD TL0 TL1 TH0 TH1 CKCON

88

P0 SP DPL DPH PCON

80

0(8) 3(B) 5(D) 7(F) 1(9) 2(A) 4(C) 6(E)

Bit Addressable

PCA0H PCA0CPH0 PCA0CPH1 PCA0CPH2 PCA0CPH4 WDTCN

PCA0MD PCA0CPM0 PCA0CPM1 PCA0CPM2 PCA0CPM3 PCA0CPM4

SMB0DAT SMB0ADR ADC0GTL ADC0GTH ADC0LTL ADC0LTH

AMX0SL

Table 10.3. Special Function Registers

SFRs are listed in alphabetical order. All undefined SFR locations are reserved.
* Refers to a register in the C8051F000/1/2/5/6/7 only.
** Refers to a register in the C8051F010/1/2/5/6/7 only.
*** Refers to a register in the C8051F005/06/07/15/16/17 only.

Address Register

0xE0 ACC Accumulator 76

0xBC ADC0CF ADC Configuration

0xE8 ADC0CN 34 5ADC Control

0xC5 ADC0GTH ADC Greater-Than Data Word (High Byte)

0xC4 ADC0GTL ADC Greater-Than Data Word (Low Byte)

0xBF ADC0H ADC Data Word (High Byte) 35*, 46**

0xBE ADC0L

Description Page No.

33 2*, 4 **

36 47*, **

36 47*, **

ADC Data Word (Low Byte) 35 46*, **

Rev. 1.7 70

*, 4 **

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Address Register

0xC7 ADC0LTH ADC Less-Than Data Word (High Byte)

0xC6 36 47*, **

0xBA AMX0CF ADC MUX Configuration

0xBB AMX0SL ADC MUX Channel Selection

0xF0 B B Register

0x8E Clock Control 144

0x9E CPT0CN Comparator 0 Control

0x9F CPT1CN Comparator 1 Control

0xD4 DAC0CN 52 DAC 0 Control

0xD3 DAC0H DAC 0 Data Word (High Byte)

0xD2 DAC0L 52DAC 0 Data Word (Low Byte)

0xD7 DAC1CN DAC 1 Control

0xD6 DAC1H DAC 1 Data Word (High Byte)

0xD5 53

0x83 DPH Data Pointer (High Byte)

0x82 DPL Data Pointer (Low Byte)

0xE6 EIE1 Extended Interrupt Enable 1

0xE7 EIE2 Extended Interrupt Enable 2

0xF6 EIP1 External Interrupt Priority 1

0xF7 EIP2 External Interrupt Priority 2

0xAF EMI0CN 92***

0xB7 FLACL Flash Access Limit

0xB6 FLSCL Flash Memory Timing Prescaler

0xA8 IE Interrupt Enable 79

0xB8 IP Interrupt Priority Control

0xB2 OSCICN Internal Oscillator Control

0xB1 OSCXCN

0x80 109

0x90 P1 Port 1 Latch

0xA0 P2 Port 2 Latch

0xB0 P3 Port 3 Latch

0xD8 PCA0CN 160Programmable Counter Array 0 Control

0xFA PCA0CPH0 PCA Capture Module 0 Data Word (High Byte) 163

0xFB PCA0CPH1 PCA Capture Module 1 Data Word (High Byte)

0xFC PCA0CPH2 PCA Capture Module 2 Data Word (High Byte)

0xFD PCA0CPH3

0xFE PCA0CPH4 163PCA Capture Module 4 Data Word (High Byte)

0xEA PCA0CPL0 PCA Capture Module 0 Data Word (Low Byte)

0xEB PCA0CPL1 PCA Capture Module 1 Data Word (Low Byte)

0xEC 163

0xED PCA0CPL3

ADC0LTL ADC Less-Than Data Word (Low Byte)

CKCON

DAC1L DAC 1 Data Word (Low Byte)

P0 Port 0 Latch

PCA0CPL2 PCA Capture Module 2 Data Word (Low Byte)

Description Page No.

36 47*, **

31 42*, **

32 43*, **

76

56

58

52

53

53

74

74

81

82

83

84

External Memory Interface Control

90***

91

80

100

External Oscillator Control 101

110

111

112

163

163

PCA Capture Module 3 Data Word (High Byte) 163

163

163

PCA Capture Module 3 Data Word (Low Byte) 163

71 Rev. 1.7

C8051F000/1/2/5/6/7

Address Register

0xEE PCA0CPL4 PCA Capture Module 4 Data Word (Low Byte)

0xDA PCA0CPM0 Programmable Counter Array 0 Capture/Compare 0

0xDB PCA0CPM1 Programmable Counter Array 0 Capture/Compare 1

0xDC PCA0CPM2 Programmable Counter Array 0 Capture/Compare 2

0xDD PCA0CPM3 162Programmable Counter Array 0 Capture/Compare 3

0xDE PCA0CPM4 Programmable Counter Array 0 Capture/Compare 4

0xF9 PCA0H PCA Counter/Timer Data Word (High Byte)

0xE9 PCA0L PCA Counter/Timer Data Word (Low Byte)

0xD9 PCA0MD

0x87 PCON Power Control 86

0xA4 PRT0CF Port 0 Configuration

0xA5 PRT1CF Port 1 Configuration

0xAD PRT1IF Port 1 Interrupt Flags 110

0xA6 PRT2CF

0xA7 PRT3CF Port 3 Configuration

0x8F PSCTL Program Store RW Control

0xD0 PSW 75Program Status Word

0xCB RCAP2H Counter/Timer 2 Capture (High Byte) 151

0xCA RCAP2L 151Counter/Timer 2 Capture (Low Byte)

0xD1 61

0xEF RSTSRC

0x99 136

0x98 SCON

0xC3 SMB0ADR 120SMBus 0 Address

0xC0 SMB0CN

0xCF SMB0CR 119SMBus 0 Clock Rate

0xC2 120

0xC1

0x81 SP 74

0x9A SPI0CFG

0x9D SPI0CKR 129

0xF8 SPI0CN SPI Bus Control 128

0x9B SPI0DAT 129SPI Port 1Data

0xC8 T2CON Counter/Timer 2 Control 150

0x88 TCON

0x8C 145

0x8D TH1

0xCD TH2 151

0x8A TL0 Counter/Timer 0 Data Word (Low Byte)

0x8B TL1 Counter/Timer 1 Data Word (Low Byte)

0xCC 151

REF0CN Voltage Reference Control Register

SBUF Serial Data Buffer (UART)

SMB0DAT SMBus 0 Data

SMB0STA SMBus 0 Status 121

TH0 Counter/Timer 0 Data Word (High Byte)

TL2 Counter/Timer 2 Data Word (Low Byte)

Description Page No.

Programmable Counter Array 0 Mode 161

Port 2 Configuration 111

Reset Source Register 97

Serial Port Control (UART) 137

SMBus 0 Control 118

Stack Pointer

Serial Peripheral Interface Configuration 127

SPI Clock Rate

Counter/Timer Control 142

Counter/Timer 1 Data Word (High Byte) 145

Counter/Timer 2 Data Word (High Byte)

C8051F010/1/2/5/6/7

163

162

162

162

162

163

163

109

110

112

88

145

145

Rev. 1.7 72

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Address Register

0x89 TMOD

0x91 152

0x95 TMR3H

0x94 TMR3L 153Timer 3 Low

0x93 TMR3RLH 153Timer 3 Reload High

0x92 TMR3RLL 153 Timer 3 Reload Low

0xFF Watchdog Timer Control 96

0xE1 Port I/O Crossbar Configuration 1 105

0xE2 XBR1 107Port I/O Crossbar Configuration 2

0xE3 XBR2 108Port I/O Crossbar Configuration 3

0x84-86, 0x96-97, 0x9C,
0xA1-A3, 0xA9-AC,
0xAE, 0xB3-B5, 0xB9,
0xBD, 0xC9, 0xCE,

0xDF, 0xE4-E5, 0xF1-F5
* Refers to a register in the C8051F000/1/2/5/6/7 only.
** Refers to a register in the C8051F010/1/2/5/6/7 only.
*** Refers to a register in the C8051F005/06/07/15/16/17 only.

TMR3CN Timer 3 Control

WDTCN

XBR0

Description Page No.

Counter/Timer Mode 143

Timer 3 High 153

Reserved

73 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

10.3.1. 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 l. 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.

Figure 10.3. SP: Stack Pointer

R/W R/W

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1

0x81

R/W R/W R/W R/W R/W R/W Reset Value

00000111

Bit0

SFR Address:

Bits 7-0: 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.

Figure 10.4. DPL: Data Pointer Low Byte

R/W R/W R/W R/W R/W R/W

00000000

Bit7 Bit6 Bit5 Bit4 Bit2 Bit0

0x82

R/W R/W Reset Value

Bit3 Bit1

SFR Address:

Bits 7-0: DPL: Data Pointer Low.

The DPL register is the low byte of the 16-bit DPTR. DPTR is used to access indirectly
addressed RAM and Flash Memory.

Figure 10.5. DPH: Data Pointer High Byte

R/W R/W R/W R/W R/W R/W Reset Value

Bit7 Bit6 Bit5 Bit4 Bit1

Bits 7-0: DPH: Data Pointer High.

The DPH register is the high byte of the 16-bit DPTR. DPTR is used to access indirectly
addressed RAM and Flash Memory.

00000000

0x83

R/W R/W

Bit3 Bit2 Bit0

SFR Address:

Rev. 1.7 74

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 10.6. PSW: Program Status Word

R/W R/W R/W R/W R/W R/W R/W

PARITY 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit0

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 10.7. ACC: Accumulator

R/W R/W R/W

ACC.7 ACC.6 ACC.5 ACC.3 ACC.2 ACC.1 ACC.0 00000000

Bit7 Bit6 Bit5 Bit3 Bit2 Bit1 Bit0

R/W R/W R/W R/W R/W Reset Value

ACC.4

Bit4

(bit addressable)

SFR Address:

0xE0

Bits 7-0: ACC: Accumulator

This register is the accumulator for arithmetic operations.

Figure 10.8. B: B Register

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

R/W R/W

Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

(bit addressable)

SFR Address:

0xF0

Bits 7-0: B: B Register

This register serves as a second accumulator for certain arithmetic operations.

Rev. 1.7 76

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

10.4. INTERRUPT HANDLER

The CIP-51 includes an extended interrupt system supporting a total of 22 interrupt sources with two priority levels.
The allocation of interrupt sources between on-chip peripherals and external inputs 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
an SFR (IE-EIE2). 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 interrupt-enable settings.

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.

10.4.1. MCU Interrupt Sources and Vectors

The MCUs allocate 12 interrupt sources to on-chip peripherals. Up to 10 additional external interrupt sources are
available depending on the I/O pin configuration of the device. 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 10.4. Refer to the datasheet 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).

10.4.2. External Interrupts

Two of the external interrupt sources (/INT0 and /INT1) are configurable as active-low level-sensitive or active-low
edge-sensitive inputs depending on the setting of IT0 (TCON.0) and IT1 (TCON.2). IE0 (TCON.1) and IE1
(TCON.3) serve as the interrupt-pending flag 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 interrupt­pending flag follows the state of the external interrupt’s input pin. 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.

The remaining four external interrupts (External Interrupts 4-7) are active-low, edge-sensitive inputs. The interrupt­pending flags for these interrupts are in the Port 1 Interrupt Flag Register shown in Figure 15.10.

77 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 10.4. Interrupt Summary

Interrupt Source

Reset 0x0000 Top None Always enabled

External Interrupt 0 (/INT0) 0x0003 0 IE0 (TCON.1) EX0 (IE.0)

Timer 0 Overflow 0x000B 1 TF0 (TCON.5) ET0 (IE.1)

External Interrupt 1 (/INT1) 0x0013 2 IE1 (TCON.3) EX1 (IE.2)

Timer 1 Overflow 0x001B 3 TF1 (TCON.7) ET1 (IE.3)

Serial Port (UART) 0x0023 4 RI (SCON.0)

Timer 2 Overflow (or EXF2) 0x002B 5 TF2 (T2CON.7) ET2 (IE.5)

Serial Peripheral Interface 0x0033 6 SPIF (SPI0CN.7)

SMBus Interface 0x003B 7 SI (SMB0CN.3) ESMB0 (EIE1.1)

ADC0 Window Comparison 0x0043 8 ADWINT (ADC0CN.2) EWADC0 (EIE1.2)

Programmable Counter Array 0 0x004B 9 CF (PCA0CN.7)

Comparator 0 Falling Edge 0x0053 10 CP0FIF (CPT0CN.4) ECP0F (EIE1.4)

Comparator 0 Rising Edge 0x005B 11 CP0RIF (CPT0CN.5) ECP0R (EIE1.5)

Comparator 1 Falling Edge 0x0063 12 ECP1F (EIE1.6) CP1FIF (CPT1CN.4)

Comparator 1 Rising Edge CP1RIF (CPT1CN.5)

Timer 3 Overflow 0x0073 14 TF3 (TMR3CN.7) ET3 (EIE2.0)

ADC0 End of Conversion 0x007B 15 ADCINT (ADC0CN.5) EADC0 (EIE2.1)

External Interrupt 4 0x0083 16 IE4 (PRT1IF.4) EX4 (EIE2.2)

External Interrupt 5 0x008B 17 IE5 (PRT1IF.5) EX5 (EIE2.3)

External Interrupt 6 0x0093 18 IE6 (PRT1IF.6) EX6 (EIE2.4)

External Interrupt 7 0x009B 19 IE7 (PRT1IF.7) EX7 (EIE2.5)

Unused Interrupt Location 0x00A3 20 None Reserved (EIE2.6)

External Crystal OSC Ready 0x00AB 21 XTLVLD (OSCXCN.7) EXVLD (EIE2.7)

Interrupt

Vector

0x006B 13 ECP1R (EIE1.7)

10.4.3. 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-EIP2) 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.

10.4.4. 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 5 system clock
cycles: 1 clock cycle to detect the interrupt and 4 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 instruction. In this case, the response time is 18 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 4
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.

Priority

Order

Interrupt-Pending Flag Enable

ES (IE.4)

TI (SCON.1)

ESPI0 (EIE1.0)
WCOL (SPI0CN.6)
MODF (SPI0CN.5)
RXOVRN (SPI0CN.4)

EPCA0 (EIE1.3)
CCFn (PCA0CN.n)

Rev. 1.7 78

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

10.4.5. Interrupt Register Descriptions

The SFRs used to enable the interrupt sources and set their priority level are described below. Refer to the datasheet
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).

Figure 10.9. IE: Interrupt Enable

R/W R/W R/W R/W R/W R/W R/W Reset Value

EA IEGF0 ET2 ES ET1 EX1 ET0 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit0

Bit7: EA: Enable All Interrupts.
This bit globally enables/disables all interrupts. It overrides the individual interrupt mask

0: Disable all interrupt sources.
1: Enable each interrupt according to its individual mask setting.

Bit6: IEGF0: General Purpose Flag 0.

Bit5: ET2: Enable Timer 2 Interrupt.

0: Disable all Timer 2 interrupts.
1: Enable interrupt requests generated by the TF2 flag (T2CON.7)

Bit4: ES: Enable Serial Port (UART) Interrupt.

0: Disable all UART interrupts.
1: Enable interrupt requests generated by the R1 flag (SCON.0) or T1 flag (SCON.1).

Bit3: ET1: Enable Timer 1 Interrupt.

0: Disable all Timer 1 interrupts.
1: Enable interrupt requests generated by the TF1 flag (TCON.7).

Bit2: EX1: Enable External Interrupt 1.

0: Disable external interrupt 1.
1: Enable interrupt requests generated by the /INT1 pin.

Bit1: ET0: Enable Timer 0 Interrupt.

1: Enable interrupt requests generated by the TF0 flag (TCON.5).

Bit0: EX0: Enable External Interrupt 0.

0: Disable external interrupt 0.
1: Enable interrupt requests generated by the /INT0 pin.

R/W

settings.

This is a general purpose flag for use under software control.

This bit sets the masking of the Timer 2 interrupt.

This bit sets the masking of the Serial Port (UART) interrupt.

This bit sets the masking of the Timer 1 interrupt.

This bit sets the masking of external interrupt 1.

This bit sets the masking of the Timer 0 interrupt.
0: Disable all Timer 0 interrupts.

This bit sets the masking of external interrupt 0.

Bit1

(bit addressable)

EX0

SFR Address:

0xA8

79 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 10.10. IP: Interrupt Priority

R/W R/W

- - PT2 PS PT1 PT0 PX0 00000000

Bit7 Bit6 Bit5 Bit4

R/W R/W R/W R/W R/W R/W Reset Value

PX1

Bit3 Bit2 Bit1 Bit0

(bit addressable)

SFR Address:

0xB8

Bits7-6: UNUSED. Read = 11b, Write = don’t care.

Bit5: PT2 Timer 2 Interrupt Priority Control.

0: Timer 2 interrupts set to low priority level.
1: Timer 2 interrupts set to high priority level.

Bit4: PS: Serial Port (UART) Interrupt Priority Control.

0: UART interrupts set to low priority level.
1: UART interrupts set to high priority level.

Bit3: PT1: Timer 1 Interrupt Priority Control.

0: Timer 1 interrupts set to low priority level.
1: Timer 1 interrupts set to high priority level.

Bit2: PX1: External Interrupt 1 Priority Control.

0: External Interrupt 1 set to low priority level.
1: External Interrupt 1 set to high priority level.

Bit1: PT0: Timer 0 Interrupt Priority Control.

0: Timer 0 interrupt set to low priority level.
1: Timer 0 interrupt set to high priority level.

Bit0: PX0: External Interrupt 0 Priority Control.

0: External Interrupt 0 set to low priority level.
1: External Interrupt 0 set to high priority level.

This bit sets the priority of the Timer 2 interrupts.

This bit sets the priority of the Serial Port (UART) interrupts.

This bit sets the priority of the Timer 1 interrupts.

This bit sets the priority of the External Interrupt 1 interrupts.

This bit sets the priority of the Timer 0 interrupts.

This bit sets the priority of the External Interrupt 0 interrupts.

Rev. 1.7 80

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 10.11. EIE1: Extended Interrupt Enable 1

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

ECP1R ECP1F ECP0R ECP0F EPCA0 EWADC0 ESMB0 ESPI0 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit0

Bit1

Bit7: ECP1R: Enable Comparator 1 (CP1) Rising Edge Interrupt.

0: Disable CP1 Rising Edge interrupt.
1: Enable interrupt requests generated by the CP1RIF flag (CPT1CN.5).

Bit6: ECP1F: Enable Comparator 1 (CP1) Falling Edge Interrupt.

0: Disable CP1 Falling Edge interrupt.
1: Enable interrupt requests generated by the CP1FIF flag (CPT1CN.4).

Bit5: ECP0R: Enable Comparator 0 (CP0) Rising Edge Interrupt.

0: Disable CP0 Rising Edge interrupt.
1: Enable interrupt requests generated by the CP0RIF flag (CPT0CN.5).

Bit4: ECP0F: Enable Comparator 0 (CP0) Falling Edge Interrupt.

0: Disable CP0 Falling Edge interrupt.
1: Enable interrupt requests generated by the CP0FIF flag (CPT0CN.4).

Bit3: EPCA0: Enable Programmable Counter Array (PCA0) Interrupt.

0: Disable all PCA0 interrupts.
1: Enable interrupt requests generated by PCA0.

Bit2: EWADC0: Enable Window Comparison ADC0 Interrupt.

0: Disable ADC0 Window Comparison Interrupt.
1: Enable Interrupt requests generated by ADC0 Window Comparisons.

Bit1: ESMB0: Enable SMBus 0 Interrupt.

1: Enable interrupt requests generated by the SI flag (SMB0CN.3).

Bit0: ESPI0: Enable Serial Peripheral Interface 0 Interrupt.

0: Disable all SPI0 interrupts.
1: Enable Interrupt requests generated by SPI0.

This bit sets the masking of the CP1 interrupt.

This bit sets the masking of the CP1 interrupt.

This bit sets the masking of the CP0 interrupt.

This bit sets the masking of the CP0 interrupt.

This bit sets the masking of the PCA0 interrupts.

This bit sets the masking of ADC0 Window Comparison interrupt.

This bit sets the masking of the SMBus interrupt.
0: Disable all SMBus interrupts.

This bit sets the masking of SPI0 interrupt.

SFR Address:

0xE

6

81 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 10.12. EIE2: Extended Interrupt Enable 2

R/W R/W R/W R/W R/W R/W R/W R/W

EXVLD - EX7 EX6 EX5 EX4 EADC0 ET3 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

Reset Value

SFR Address:

0xE

7

Bit7: EXVLD: Enable External Clock Source Valid (XTLVLD) Interrupt.

0: Disable all XTLVLD interrupts.
1: Enable interrupt requests generated by the XTLVLD flag (OSCXCN.7)

Bit6: Reserved. Must Write 0. Reads 0.

Bit5: EX7: Enable External Interrupt 7.

0: Disable External Interrupt 7.
1: Enable interrupt requests generated by the External Interrupt 7 input pin.

Bit4: EX6: Enable External Interrupt 6.

0: Disable External Interrupt 6.
1: Enable interrupt requests generated by the External Interrupt 6 input pin.

Bit3: EX5: Enable External Interrupt 5.

0: Disable External Interrupt 5.
1: Enable interrupt requests generated by the External Interrupt 5 input pin.

Bit2: EX4: Enable External Interrupt 4.

0: Disable External Interrupt 4.
1: Enable interrupt requests generated by the External Interrupt 4 input pin.

Bit1: EADC0: Enable ADC0 End of Conversion Interrupt.

0: Disable ADC0 Conversion Interrupt.
1: Enable interrupt requests generated by the ADC0 Conversion Interrupt.

Bit0: ET3: Enable Timer 3 Interrupt.

0: Disable all Timer 3 interrupts.
1: Enable interrupt requests generated by the TF3 flag (TMR3CN.7)

This bit sets the masking of the XTLVLD interrupt.

This bit sets the masking of External Interrupt 7.

This bit sets the masking of External Interrupt 6.

This bit sets the masking of External Interrupt 5.

This bit sets the masking of External Interrupt 4.

This bit sets the masking of the ADC0 End of Conversion Interrupt.

This bit sets the masking of the Timer 3 interrupt.

Rev. 1.7 82

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 10.13. EIP1: Extended Interrupt Priority 1

R/W R/W R/W R/W Reset Value

PCP1R PCP1F PCP0R PCP0F PSPI0

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

6

R/W R/W R/W R/W

PPCA0 PWADC0 PSMB0 00000000

SFR Address:

0xF

Bit7: PCP1R: Comparator 1 (CP1) Rising Interrupt Priority Control.

0: CP1 rising interrupt set to low priority level.

Bit6: PCP1F: Comparator 1 (CP1) Falling Interrupt Priority Control.

0: CP1 falling interrupt set to low priority level.

Bit5: PCP0R: Comparator 0 (CP0) Rising Interrupt Priority Control.

0: CP0 rising interrupt set to low priority level.

Bit4: PCP0F: Comparator 0 (CP0) Falling Interrupt Priority Control.

0: CP0 falling interrupt set to low priority level.

Bit3: PPCA0: Programmable Counter Array (PCA0) Interrupt Priority Control.

0: PCA0 interrupt set to low priority level.

Bit2: PWADC0: ADC0 Window Comparator Interrupt Priority Control.

0: ADC0 Window interrupt set to low priority level.

Bit1: PSMB0: SMBus 0 Interrupt Priority Control.

0: SMBus interrupt set to low priority level.
1: SMBus interrupt set to high priority level.

Bit0: PSPI0: Serial Peripheral Interface 0 Interrupt Priority Control.

0: SPI0 interrupt set to low priority level.
1: SPI0 interrupt set to high priority level.

This bit sets the priority of the CP1 interrupt.

1: CP1 rising interrupt set to high priority level.

This bit sets the priority of the CP1 interrupt.

1: CP1 falling interrupt set to high priority level.

This bit sets the priority of the CP0 interrupt.

1: CP0 rising interrupt set to high priority level.

This bit sets the priority of the CP0 interrupt.

1: CP0 falling interrupt set to high priority level.

This bit sets the priority of the PCA0 interrupt.

1: PCA0 interrupt set to high priority level.

This bit sets the priority of the ADC0 Window interrupt.

1: ADC0 Window interrupt set to high priority level.

This bit sets the priority of the SMBus interrupt.

This bit sets the priority of the SPI0 interrupt.

83 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 10.14. EIP2: Extended Interrupt Priority 2

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

PXVLD - PX4 PADC0 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xF7

PX7 PX6 PX5 PT3

SFR Address:

Bit7: PXVLD: External Clock Source Valid (XTLVLD) Interrupt Priority Control.

0: XTLVLD interrupt set to low priority level.

Bit6: Reserved: Must write 0. Reads 0.

Bit5: PX7: External Interrupt 7 Priority Control.

0: External Interrupt 7 set to low priority level.
1: External Interrupt 7 set to high priority level.

Bit4: PX6: External Interrupt 6 Priority Control.

0: External Interrupt 6 set to low priority level.
1: External Interrupt 6 set to high priority level.

Bit3: PX5: External Interrupt 5 Priority Control.

0: External Interrupt 5 set to low priority level.
1: External Interrupt 5 set to high priority level.

Bit2: PX4: External Interrupt 4 Priority Control.

0: External Interrupt 4 set to low priority level.
1: External Interrupt 4 set to high priority level.

Bit1: PADC0: ADC End of Conversion Interrupt Priority Control.

0: ADC0 End of Conversion interrupt set to low priority level.
1: ADC0 End of Conversion interrupt set to high priority level.

Bit0: PT3: Timer 3 Interrupt Priority Control.

0: Timer 3 interrupt set to low priority level.
1: Timer 3 interrupt set to high priority level.

This bit sets the priority of the XTLVLD interrupt.

1: XTLVLD interrupt set to high priority level.

This bit sets the priority of the External Interrupt 7.

This bit sets the priority of the External Interrupt 6.

This bit sets the priority of the External Interrupt 5.

This bit sets the priority of the External Interrupt 4.

This bit sets the priority of the ADC0 End of Conversion Interrupt.

This bit sets the priority of the Timer 3 interrupts.

Rev. 1.7 84

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

10.5. 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 external 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 system clock is stopped. 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. Figure 1 .
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 put into low power mode. Digital peripherals, such as timers or
serial buses, draw little power whenever they are not in use. Turning off the oscillator saves even more power, but
requires a reset to restart the MCU.

10.5.1. 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. 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 or /RST is asserted. The assertion of an enabled interrupt will
cause the Idle Mode Selection bit (PCON.0) to be cleared and the CPU will 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.

Note: If the instruction following the write of the IDLE bit is a single-byte instruction and an interrupt occurs during
the execution phase of the instruction that sets the IDLE bit, the CPU may not wake from Idle mode when a future
interrupt occurs. Any instructions that set the IDLE bit should be followed by an instruction that has 2 or more op­code bytes, for example:

// in ‘C’:
PCON |= 0x01; // set IDLE bit
PCON = PCON; // ... followed by a 3-cycle dummy instruction

; in assembly:
ORL PCON, #01h ; set IDLE bit
MOV PCON, PCON ; ... followed by a 3-cycle dummy instruction

If enabled, the 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. Refer to Section 13.8 Watchdog Timer for more information on the use and configuration of the
WDT.

10.5.2. 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. In Stop mode, the CPU and oscillators are stopped, effectively shutting down all digital
peripherals. Each analog peripheral must 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.

0 15

85 Rev. 1.7

C8051F000/1/2/5/6/7

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 sleep for longer than the MCD timeout of
100µsec.

C8051F010/1/2/5/6/7

Figure 10.15. PCON: Power Control Register

R/W R/W R/W R/W R/W R/W R/W Reset Value

SMOD GF4 GF3 GF2 GF1 GF0 STOP IDLE 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0x87

R/W

SFR Address:

Bit7: SMOD: Serial Port Baud Rate Doubler Enable.

Bits6-2: GF4-GF0: General Purpose Flags 4-0.

Bit1: STOP: Stop Mode Select.

Bit0: IDLE: Idle Mode Select.

0: Serial Port baud rate is that defined by Serial Port Mode in SCON.
1: Serial Port baud rate is double that defined by Serial Port Mode in SCON.

These are general purpose flags for use under software control.

Setting this bit will place the CIP-51 in Stop mode. This bit will always be read as 0.
1: Goes into power down mode. (Turns off internal oscillator).

Setting this bit will place the CIP-51 in Idle mode. This bit will always be read as 0.
1: Goes into idle mode. (Shuts off clock to CPU, but clock to Timers, Interrupts, Serial

Ports, and Analog Peripherals are still active.)

Rev. 1.7 86

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

11. FLASH MEMORY

These devices include 32k + 128 bytes of on-chip, reprogrammable Flash memory for program code and non­volatile data storage. The Flash memory can be programmed in-system, a single byte at a time, through the JTAG
interface or by software using the MOVX instruction. Once cleared to 0, a Flash bit must be erased to set it back to

1. The 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
operation is not required. The Flash memory is designed to withstand at least 20,000 write/erase cycles. Refer to
Table 11.1 for the electrical characteristics of the Flash memory.

11.1. Programming The Flash Memory

The simplest means of programming the Flash memory is through the JTAG interface using programming tools
provided by Silicon Labs or a third party vendor. This is the only means for programming a non-initialized device.
For details on the JTAG commands to program Flash memory, see Section 21.2.

The Flash memory can be programmed by software using the MOVX 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 setting the PSWE Program Store Write Enable bit (PSCTL.0) to logic 1. Writing to
Flash remains enabled until the PSWE bit is cleared by software.

Writes to Flash memory can clear bits but cannot set them. Only an erase operation can set bits in Flash. Therefore,
the byte location to be programmed must be erased before a new value can be written. The 32kbyte Flash memory
is organized in 512-byte sectors. The erase operation applies to an entire sector (setting all bytes in the sector to
0xFF). Setting the PSEE Program Store Erase Enable bit (PSCTL.1) and PSWE (PSCTL.0) bit to logic 1 and then
using the MOVX command to write a data byte to any byte location within the sector will erase an entire 512-byte
sector. The data byte written can be of any value because it is not actually written to the Flash. Flash erasure
remains enabled until the PSEE bit is cleared by software. The following sequence illustrates the algorithm for
programming the Flash memory by software:

1. Enable Flash Memory write/erase in FLSCL Register using FLASCL bits.

2. Set PSEE (PSCTL.1) to enable Flash sector erase.

3. Set PSWE (PSCTL.0) to enable Flash writes.

4. Use MOVX to write a data byte to any location within the 512-byte sector to be erased.

5. Clear PSEE to disable Flash sector erase.

6. Use MOVX to write a data byte to the desired byte location within the erased 512-byte sector. Repeat until
finished. (Any number of bytes can be written from a single byte to and entire sector.)

7. Clear the PSWE bit to disable Flash writes.

Write/Erase timing is automatically controlled by hardware based on the prescaler value held in the Flash Memory
Timing Prescaler register (FLSCL). The 4-bit prescaler value FLASCL determines the time interval for write/erase
operations. The FLASCL value required for a given system clock is shown in Figure 11.4, along with the formula
used to derive the FLASCL values. When FLASCL is set to 1111b, the write/erase operations are disabled. Note
that code execution in the 8051 is stalled while the Flash is being programmed or erased.

Table 11.1. FLASH Memory Electrical Characteristics

VDD = 2.7 to 3.6V, -40°C to +85°C unless otherwise specified.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Endurance 20k 100k Erase/Wr
Erase Cycle Time 10 ms
Write Cycle Time 40

87 Rev. 1.7

µs

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

11.2. 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 instruction and
read using the MOVC instruction.

The MCU incorporates an additional 128-byte sector of Flash memory located at 0x8000 – 0x807F. This sector can
be used for program code or data storage. However, its smaller sector size makes it particularly well suited as
general purpose, non-volatile scratchpad memory. Even though Flash memory can be written a single byte at a
time, an entire sector must be erased first. In order to change a single byte of a multi-byte data set, the data must be
moved to temporary storage. Next, the sector is erased, the data set updated and the data set returned to the original
sector. The 128-byte sector-size facilitates updating data without wasting program memory space by allowing the
use of internal data RAM for temporary storage. (A normal 512-byte sector is too large to be stored in the 256-byte
internal data memory.)

11.3. Security Options

The CIP-51 provides security options to protect the Flash memory from inadvertent modification by software as
well as prevent the viewing of proprietary program code and constants. The Program Store Write Enable
(PSCTL.0) and the Program Store Erase Enable (PSCTL.1) bits protect the Flash memory from accidental
modification by software. These bits must be explicitly set to logic 1 before software can modify the Flash memory.
Additional security features prevent proprietary program code and data constants from being read or altered across
the JTAG interface or by software running on the system controller.

A set of security lock bytes stored at 0x7DFE and 0x7DFF protect the Flash program memory from being read or
altered across the JTAG interface. Each bit in a security lock-byte protects one 4kbyte block of memory. Clearing
a bit to logic 0 in a Read lock byte prevents the corresponding block of Flash memory from being read across the
JTAG interface. Clearing a bit in the Write/Erase lock byte protects the block from JTAG erasures and/or writes.
The Read lock byte is at location 0x7DFF. The Write/Erase lock byte is located at 0x7DFE. Figure 11.2 shows the
location and bit definitions of the security bytes. The 512-byte sector containing the lock bytes can be written to,
but not erased by software. Writing to the reserved area should not be performed.

Figure 11.1. PSCTL: Program Store RW Control

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

- - - - - - PSEE PSWE 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0x8F

SFR Address:

Bits7-2: UNUSED. Read = 000000b, Write = don’t care.

Bit1: PSEE: Program Store Erase Enable.

Bit0: PSWE: Program Store Write Enable.

Setting this bit allows an entire page of the Flash program memory to be erased provided
the PSWE bit is also set. After setting this bit, 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.

Setting this bit allows writing a byte of data to the Flash program memory using the
MOVX instruction. The location must be erased before writing data.
0: Write to Flash program memory disabled.
1: Write to Flash program memory enabled.

Rev. 1.7 88

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 11.2. Flash Program Memory Security Bytes

(This Block locked only if all

other blocks are locked)

Reserved

Read Lock Byte

Write/Erase Lock Byte

Program Memory

Space

Software Read Limit

FLASH Read Lock Byte

Bits7-0: Each bit locks a corresponding block of memory. (Bit 7 is MSB.)
0: Read operations are locked (disabled) for corresponding block across the JTAG interface.
1: Read operations are unlocked (enabled) for corresponding block across the JTAG interface.

FLASH Write/Erase Lock Byte

Bits7-0: Each bit locks a corresponding block of memory.
0: Write/Erase operations are locked (disabled) for corresponding block across the JTAG interface.
1: Write/Erase operations are unlocked (enabled) for corresponding block across the JTAG interface.

FLASH Access Limit Register (FLACL)

The content of this register is used as the high byte of the 16-bit software read limit address. The 16-

bit read limit address value is calculated as 0xNN00 where NN is replaced by the contents of this
register. Software running at or above this address is prohibited from using the MOVX or MOVC
instructions to read, write, or erase, locations below this address. Any attempts to read locations
below this limit will return the value 0x00.

The lock bits can always be read and cleared to logic 0 regardless of the security setting applied to the block
containing the security bytes. This allows additional blocks to be protected after the block containing the security
bytes has been locked. However, the only means of removing a lock once set is to erase the entire program memory
space by performing a JTAG erase operation (i.e. cannot be done in user firmware). NOTE: Addressing either

security byte while performing a JTAG erase operation will automatically initiate erasure of the entire
program memory space (except for the reserved area). This erasure can only be performed via JTAG. If a
non-security byte in the 0x7C00-0x7DFF page is addressed during erasure, only that page (including the
security bytes) will be erased.

The Flash Access Limit security feature (see Figure 11.3) protects proprietary program code and data from being
read by software running on the C8051F005/06/07/15/16/17 MCUs. This feature provides support for OEMs that
wish to program the MCU with proprietary value-added firmware before distribution. The value-added firmware
can be protected while allowing additional code to be programmed in remaining program memory space later.

0x807F
0x8000
0x7FFF

0x7E00

0x7DFF

0x7DFE

0x7DFD

0x0000

Read and Write/Erase Security Bits.
(Bit 7 is MSB.)

Bit Memory Block

7

0x7000 - 0x7DFD

6

0x6000 - 0x6FFF

5

0x5000 - 0x5FFF

4

0x4000 - 0x4FFF

3

0x3000 - 0x3FFF

2

0x2000 - 0x2FFF

1

0x1000 - 0x1FFF

0

0x0000 - 0x0FFF

89 Rev. 1.7

C8051F000/1/2/5/6/7

b

The Software Read Limit (SRL) is a 16-bit address that establishes two logical partitions in the program memory
space. The first is an upper partition consisting of all the program memory locations at or above the SRL address,
and the second is a lower partition consisting of all the program memory locations starting at 0x0000 up to (but
excluding) the SRL address. Software in the upper partition can execute code in the lower partition, but is
prohibited from reading locations in the lower partition using the MOVC instruction. (Executing a MOVC
instruction from the upper partition with a source address in the lower partition will always return a data value of
0x00.) Software running in the lower partition can access locations in both the upper and lower partition without
restriction.

The Value-added firmware should be placed in the lower partition. On reset, control is passed to the value-added
firmware via the reset vector. Once the value-added firmware completes its initial execution, it branches to a
predetermined location in the upper partition. If entry points are published, software running in the upper partition
may execute program code in the lower partition, but it cannot read the contents of the lower partition. Parameters
may be passed to the program code running in the lower partition either through the typical method of placing them
on the stack or in registers before the call or by placing them in prescribed memory locations in the upper partition.

The SRL address is specified using the contents of the Flash Access Register. The 16-bit SRL address is calculated
as 0xNN00, where NN is the contents of the SRL Security Register. Thus, the SRL can be located on 256-byte
boundaries anywhere in program memory space. However, the 512-byte erase sector size essentially requires that a
512 boundary be used. The contents of a non-initialized SRL security byte is 0x00, thereby setting the SRL address
to 0x0000 and allowing read access to all locations in program memory space by default.

C8051F010/1/2/5/6/7

Figure 11.3. FLACL: Flash Access Limit (C8051F005/06/07/15/16/17 only)

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

0xB7

SFR Address:

Bits 7-0: FLACL: Flash Access Limit.

This register holds the high byte of the 16-bit program memory read/write/erase limit
address. The entire 16­replaced by contents of FLACL. A write to this register sets the Flash Access Limit. This

register can only be written once after any reset. Any subsequent writes are ignored
until the next reset.

it access limit address value is calculated as 0xNN00 where NN is

Rev. 1.7 90

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 11.4. FLSCL: Flash Memory Timing Prescaler

R/W R/W R/W R/W R/W R/W R/W R/W Reset Value

FOSE FRAE - - FLASCL

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xB6

Bit7: FOSE: Flash One-Shot Timer Enable
0: Flash One-shot timer disabled.

Bit6: FRAE: Flash Read Always Enable
0: Flash reads per one-shot timer

Bits5-4: UNUSED. Read = 00b, Write = don’t care.
Bits3-0: FLASCL: Flash Memory Timing Prescaler.

1: Flash One-shot timer enabled

1: Flash always in read mode

This register specifies the prescaler value for a given system clock required to generate the
correct timing for Flash write/erase operations. If the prescaler is set to 1111b, Flash
write/erase operations are disabled.
0000: System Clock < 50kHz
0001: 50kHz ≤ System Clock < 100kHz
0010: 100kHz ≤ System Clock < 200kHz
0011: 200kHz ≤ System Clock < 400kHz
0100: 400kHz ≤ System Clock < 800kHz
0101: 800kHz ≤ System Clock < 1.6MHz
0110: 1.6MHz ≤ System Clock < 3.2MHz
0111: 3.2MHz ≤ System Clock < 6.4MHz
1000: 6.4MHz ≤ System Clock < 12.8MHz
1001: 12.8MHz ≤ System Clock < 25.6MHz
1010: 25.6MHz ≤ System Clock < 51.2MHz *
1011, 1100, 1101, 1110: Reserved Values
1111: Flash Memory Write/Erase Disabled

The prescaler value is the smallest value satisfying the following equation:
FLASCL > log

* For test purposes. The C8051F000 family is not guaranteed for operation over 25MHz.

(System Clock / 50kHz)

2

10001111

SFR Address:

91 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

12. EXTERNAL RAM (C8051F005/06/07/15/16/17)

The C8051F005/06/07/15/16/17 MCUs 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 Figure 12.1). Note: the MOVX instruction is also used for writes to the Flash

memory. See Section 11 for details. The MOVX instruction accesses XRAM by default (i.e. PSTCL.0 = 0).

For any of the addressing modes the upper 5-bits of the 16-bit external data memory address word are “don’t cares”.
As a result, the 2048-byte RAM is mapped modulo style over the entire 64k external data memory address range.
For example, the XRAM byte at address 0x0000 is also at address 0x0800, 0x1000, 0x1800, 0x2000, etc. This is a
useful feature when doing a linear memory fill, as the address pointer doesn’t have to be reset when reaching the
RAM block boundary.

Figure 12.1. EMI0CN: External Memory Interface Control

R R R R R R/W R/W R/W Reset Value

- - - - - PGSEL2 PGSEL1 PGSEL0 00000000

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xAF

Bits 7-3: Not Used – reads 00000b
Bits 2-0: PGSEL[2:0]: XRAM Page Select Bits

000: xxxxx000b
001: xxxxx001b

011: xxxxx011b

101: xxxxx101b

111: xxxxx111b

The XRAM Page Select Bits provide 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. The upper 5-bits are “don’t cares”, so the 2k address blocks are repeated modulo
over the entire 64k external data memory address space.

010: xxxxx010b

100: xxxxx100b

110: xxxxx110b

SFR Address:

Rev. 1.7 92

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

13. RESET SOURCES

The reset circuitry of the MCUs allows the controller to be easily placed in a predefined default condition. On entry
to this reset state, the CIP-51 halts program execution, forces the external port pins to a known state and initializes
the SFRs to their defined reset values. Interrupts and timers are disabled. On exit, the program counter (PC) is
reset, and program execution starts at location 0x0000.

All of the SFRs are reset to predefined values. The reset values of the SFR bits are defined in the SFR detailed
descriptions. The contents of internal data memory are not changed during a reset and 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 are not altered.

The I/O port latches are reset to 0xFF (all logic ones), activating internal weak pull-ups which take the external I/O
pins to a high state. The weak pull-ups are enabled during and after the reset. If the source of reset is from the VDD
Monitor or writing a 1 to PORSF, the /RST pin is driven low until the end of the VDD reset timeout.

On exit from the reset state, the MCU uses the internal oscillator running at 2MHz as the system clock by default.
Refer to Section 14 for information on selecting and configuring the system clock source. The Watchdog Timer is
enabled using its longest timeout interval. (Section 13.8 details the use of the Watchdog Timer.)

There are seven sources for putting the MCU into the reset state: power-on/power-fail, external /RST pin, external
CNVSTR signal, software commanded, Comparator 0, Missing Clock Detector, and Watchdog Timer. Each reset
source is described below:

Figure 13.1. Reset Sources Diagram

(Port

I/O)

Crossbar

CP0+

CP0-

System

Clock

CNVSTR

CNVRSEF

Comparator 0

+

-

Missing

Clock

Detector

(one­shot)

EN

MCD

Enable

C0RSEF

WDT

WDT

EN

Enable

PRE

WDT

Strobe

VDD

CIP-51

Core

Supply
Monitor

+

-

(Software Reset)

SWRSF

System Reset

Supply

Reset

Timeout

(wired-OR)

Reset
Funnel

/RST

93 Rev. 1.7

C8051F000/1/2/5/6/7

13.1.

The C8051F000 family incorporates a power supply monitor that holds the MCU in the reset state until VDD rises
above the V
Electrical Characteristics of the power supply monitor circuit.) The /RST pin is asserted (low) until the end of the
100ms VDD Monitor timeout in order to allow the VDD supply to become stable.

On exit from a power-on reset, the PORSF flag (RSTSRC.1) is set by hardware to logic 1. All of the other reset
flags in the RSTSRC Register are indeterminate. PORSF is cleared by a reset from any other source. 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 content of internal data memory should be assumed to be
undefined after a power-on reset.

Power-on Reset

level during power-up. (See Figure 13.2 for timing diagram, and refer to Table 1 .1 for the

RST

C8051F010/1/2/5/6/7

3

13.2. Software Forced Reset

Writing a 1 to the PORSF bit forces a Power-On Reset as described in Section 13.1.

Figure 13.2. VDD Monitor Timing Diagram

Logic HIGH

Logic LOW

13.3.

When a power-down transition or power irregularity causes VDD to drop below V
will drive the /RST pin low and return the CIP-51 to the reset state (see Figure 13.2). When VDD returns to a level
above V
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 is set, the data may no longer be valid.

Power-fail Reset

RST

volts

2.70

2.40

2.0

1.0

/RST

, the CIP-51 will leave the reset state in the same manner as that for the power-on reset. Note that even

V

RST

D

D

V

t

100ms 100ms

, the power supply monitor

RST

Rev. 1.7 94

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

13.4. External Reset

The external /RST pin provides a means for external circuitry to force the MCU into a reset state. Asserting an
active-low signal on the /RST pin will cause the MCU to enter the reset state. Although there is a weak internal
pullup, it may be desirable to provide an external pull-up and/or decoupling of the /RST pin to avoid erroneous
noise-induced resets. The MCU will remain in reset until at least 12 clock cycles after the active-low /RST signal is
removed. The PINRSF flag (RSTSRC.0) is set on exit from an external reset. The /RST pin is also 5V tolerant.

13.5. Missing Clock Detector Reset

The Missing Clock Detector is essentially a one-shot circuit that is triggered by the MCU system clock. If the
system clock goes away for more than 100µs, the one-shot will time out and generate a reset. After a Missing Clock
Detector reset, the MCDRSF flag (RSTSRC.2) will be set, signifying the MSD as the reset source; otherwise, this
bit reads 0. The state of the /RST pin is unaffected by this reset. Setting the MSCLKE bit in the OSCICN register
(see Figure 14.2) enables the Missing Clock Detector.

13.6. Comparator 0 Reset

Comparator 0 can be configured as an active-low reset input by writing a 1 to the C0RSEF flag (RSTSRC.5).
Comparator 0 should be enabled using CPT0CN.7 (see Figure 8.3) at least 20µs prior to writing to C0RSEF to
prevent any turn-on chatter on the output from generating an unwanted reset. When configured as a reset, if the
non-inverting input voltage (on CP0+) is less than the inverting input voltage (on CP0-), the MCU is put into the
reset state. After a Comparator 0 Reset, the C0RSEF flag (RSTSRC.5) will read 1 signifying Comparator 0 as the
reset source; otherwise, this bit reads 0. The state of the /RST pin is unaffected by this reset. Also, Comparator 0
can generate a reset with or without the system clock.

13.7. External CNVSTR Pin Reset

The external CNVSTR signal can be configured as an active-low reset input by writing a 1 to the CNVRSEF flag
(RSTSRC.6). The CNVSTR signal can appear on any of the P0, P1, or P2 I/O pins as described in Section 15.1.
(Note that the Crossbar must be configured for the CNVSTR signal to be routed to the appropriate Port I/O.) The
Crossbar should be configured and enabled before the CNVRSEF is set to configure CNVSTR as a reset source.
When configured as a reset, CNVSTR is active-low and level sensitive. After a CNVSTR reset, the CNVRSEF flag
(RSTSRC.6) will read 1 signifying CNVSTR as the reset source; otherwise, this bit reads 0. The state of the /RST
pin is unaffected by this reset.

13.8. Watchdog Timer Reset

The MCU includes a programmable Watchdog Timer (WDT) running off the system clock. The WDT will force
the MCU into the reset state when the watchdog timer overflows. To prevent the reset, the WDT must be restarted
by application software before the overflow occurs. If the system experiences a software/hardware malfunction
preventing the software from restarting the WDT, the WDT will overflow and cause a reset. This should prevent
the system from running out of control.

The WDT is automatically enabled and started with the default maximum time interval on exit from all resets. If
desired the WDT can be disabled by system software or locked on to prevent accidental disabling. Once locked, the
WDT cannot be disabled until the next system reset. The state of the /RST pin is unaffected by this reset.

95 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

13.8.1. Watchdog Usage

The WDT consists of a 21-bit timer running from the programmed system clock. The timer measures the period
between specific writes to its control register. If this period exceeds the programmed limit, a WDT reset is
generated. The WDT can be enabled and disabled as needed in software, or can be permanently enabled if desired.
Watchdog features are controlled via the Watchdog Timer Control Register (WDTCN) shown in Figure 13.3.

Enable/Reset WDT

The watchdog timer is both enabled and the countdown restarted by writing 0xA5 to the WDTCN register. The
user’s application software should include periodic writes of 0xA5 to WDTCN as needed to prevent a watchdog
timer overflow. The WDT is enabled and restarted as a result of any system reset.

Disable WDT

Writing 0xDE followed by 0xAD to the WDTCN register disables the WDT. The following code segment
illustrates disabling the WDT.

CLR EA ; disable all interrupts

MOV WDTCN,#0DEh ; disable software

MOV WDTCN,#0ADh ; watchdog timer

SETB EA ; re-enable interrupts

The writes of 0xDE and 0xAD must occur within 4 clock cycles of each other, or the disable operation is ignored.
Interrupts should be disabled during this procedure to avoid delay between the two writes.

Disable WDT Lockout

Writing 0xFF to WDTCN locks out the disable feature. Once locked out, the disable operation is ignored until the
next system reset. Writing 0xFF does not enable or reset the watchdog timer. Applications always intending to use
the watchdog should write 0xFF to WDTCN in their initialization code.

Setting WDT Interval

WDTCN.[2:0] control the watchdog timeout interval. The interval is given by the following equation:

3+WDTCN[2:0]

4

For a 2MHz system clock, this provides an interval range of 0.032msec to 524msec. WDTCN.7 must be a 0 when
setting this interval. Reading WDTCN returns the programmed interval. WDTCN.[2:0] is 111b after a system
reset.

x T

SYSCLK

, (where T

is the system clock period).

SYSCLK

Figure 13.3. WDTCN: Watchdog Timer Control Register

R/W R/W R/W R/W R/W R/W R/W Reset Value

xxxxx111

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

0xFF

R/W

SFR Address:

Bits7-0: WDT Control
Writing 0xA5 both enables and reloads the WDT.
Writing 0xDE followed within 4 clocks by 0xAD disables the WDT.
Writing 0xFF locks out the disable feature.
Bit4: Watchdog Status Bit (when Read)
Reading the WDTCN.[4] bit indicates the Watchdog Timer Status.
0: WDT is inactive
1: WDT is active
Bits2-0: Watchdog Timeout Interval Bits
The WDTCN.[2:0] bits set the Watchdog Timeout Interval. When writing these bits,

WDTCN.7 must be set to 0.

Rev. 1.7 96

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 13.4. RSTSRC: Reset Source Register

R R/W R/W R/W R R R/W R Reset Value

JTAGRST CNVRSEF C0RSEF SWRSEF WDTRSF MCDRSF PORSF PINRSF xxxxxxxx

Bit7 Bit6 Bit5 Bit4 Bit2 Bit1 Bit0

0xEF

Bit3

(Note: Do not use read-modify-write operations on this register.)

Bit7: JTAGRST. JTAG Reset Flag.

1: JTAG is in reset state.
Bit6: CNVRSEF: Convert Start Reset Source Enable and Flag
Write

1: CNVSTR is a reset source (active low)
Read

1: Source of prior reset was from CNVSTR
Bit5: C0RSEF: Comparator 0 Reset Enable and Flag
Write

1: Comparator 0 is a reset source (active low)
Read
Note: The value read from C0RSEF is not defined if Comparator 0 has not been enabled as

1: Source of prior reset was from Comparator 0
Bit4: SWRSF: Software Reset Force and Flag
Write
0: No Effect
1: Forces an internal reset. /RST pin is not effected.

0: Prior reset source was not from write to the SWRSF bit.
1: Prior reset source was from write to the SWRSF bit.
Bit3: WDTRSF: Watchdog Timer Reset Flag
0: Source of prior reset was not from WDT timeout.
1: Source of prior reset was from WDT timeout.
Bit2: MCDRSF: Missing Clock Detector Flag
0: Source of prior reset was not from Missing Clock Detector timeout.
1: Source of prior reset was from Missing Clock Detector timeout.
Bit1: PORSF: Power-On Reset Force and Flag
Write
0: No effect
1: Forces a Power-On Reset. /RST is driven low.

0: Source of prior reset was not from POR.
1: Source of prior reset was from POR.
Bit0: PINRSF: HW Pin Reset Flag
0: Source of prior reset was not from /RST pin.
1: Source of prior reset was from /RST pin.

0: JTAG is not currently in reset state.

0: CNVSTR is not a reset source

0: Source of prior reset was not from CNVSTR

0: Comparator 0 is not a reset source

a reset source.
0: Source of prior reset was not from Comparator 0

Read

Read

SFR Address:

97 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Table 13.1. Reset Electrical Characteristics

-40°C to +85°C unless otherwise specified.

PARAMETER CONDITIONS MIN TYP MAX UNITS

/RST Output Low Voltage IOL = 8.5mA, VDD = 2.7 to 3.6V 0.6 V
/RST Input High Voltage 0.7 x

VDD

/RST Input Low Voltage 0.3 x

/RST Input Leakage Current /RST = 0.0V 20
VDD for /RST Output Valid 1.0 V
AV+ for /RST Output Valid 1.0 V
VDD POR Threshold (V
Reset Time Delay /RST rising edge after crossing reset

Missing Clock Detector
Timeout

) 2.40 2.55 2.70 V

RST

80 100 120 ms
threshold
Time from last system clock to reset
generation

100 220 500

V

V

VDD

µA

µs

Rev. 1.7 98

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

14. OSCILLATOR

Each MCU includes an internal oscillator and an external oscillator drive circuit, either of which can generate the
system clock. The MCUs boot from the internal oscillator after any reset. The internal oscillator starts up instantly.
It can be enabled/disabled and its frequency can be changed using the Internal Oscillator Control Register
(OSCICN) as shown in Figure 14.2. The internal oscillator’s electrical specifications are given in Table 14.1.

Both oscillators are disabled when the /RST pin is held low. The MCUs can run from the internal oscillator or
external oscillator, and switch between the two at will using the CLKSL bit in the OSCICN Register. The external
oscillator requires an external resonator, parallel-mode crystal, capacitor, or RC network connected to the
XTAL1/XTAL2 pins (see Figure 14.1). The oscillator circuit must be configured for one of these sources in the
OSCXCN register. An external CMOS clock can also provide the system clock via overdriving the XTAL1 pin.
The XTAL1 and XTAL2 pins are 3.6V (not 5V) tolerant. The external oscillator can be left enabled and running
even when the MCU has switched to using the internal oscillator.

Figure 14.1. Oscillator Diagram

opt. 4 opt. 3

XTAL1

XTAL2

opt. 2

AV+

opt. 1

XTAL1XTAL1

XTAL1

XTAL2

AGND

VDD

AV+

OSCICN

MSCLKE

Internal Clock

Generator

Input

Circuit

XTLVLD

XOSCMD2

XOSCMD1

OSCXCN

IFCN1

CLKSL

EN

OSC

IOSCEN

XFCN2

XFCN1

IFCN0

SYSCLK

XFCN0

IFRDY

XOSCMD0

99 Rev. 1.7

C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7

Figure 14.2. OSCICN: Internal Oscillator Control Register

R/W R/W R R/W R/W R/W Reset Value

MSCLKE - - IFRDY CLKSL IFCN1 IFCN0

Bit7 Bit6 Bit3 Bit2 Bit1 Bit0

0xB2

Bit7: MSCLKE: Missing Clock Enable Bit
0: Missing Clock Detector Disabled
1: Missing Clock Detector Enabled; triggers a reset if a missing clock is detected
Bits6-5: UNUSED. Read = 00b, Write = don’t care
Bit4: IFRDY: Internal Oscillator Frequency Ready Flag
0: Internal Oscillator Frequency not running at speed specified by the IFCN bits.
1: Internal Oscillator Frequency running at speed specified by the IFCN bits.
Bit3: CLKSL: System Clock Source Select Bit
0: Uses Internal Oscillator as System Clock.
1: Uses External Oscillator as System Clock.
Bit2: IOSCEN: Internal Oscillator Enable Bit

Bits1-0: IFCN1-0: Internal Oscillator Frequency Control Bits

0: Internal Oscillator Disabled
1: Internal Oscillator Enabled

00: Internal Oscillator typical frequency is 2MHz.
01: Internal Oscillator typical frequency is 4MHz.
10: Internal Oscillator typical frequency is 8MHz.
11: Internal Oscillator typical frequency is 16MHz.

R/W R/W

IOSCEN 00000100

Bit5 Bit4

SFR Address:

Table 14.1. Internal Oscillator Electrical Characteristics

-40°C to +85°C unless otherwise specified.

PARAMETER

Internal Oscillator
Frequency

Internal Oscillator Current
Consumption (from VDD)
Internal Oscillator
Temperature Stability
Internal Oscillator Power
Supply (VDD) Stability

OSCICN.[1:0] = 00
OSCICN.[1:0] = 01
OSCICN.[1:0] = 10
OSCICN.[1:0] = 11
OSCICN.2 = 1 200

4

6.4 %/V

CONDITIONS MIN TYP MAX UNITS

1.5

3.1

6.2

12.3

2
4
8

16

2.4

4.8

9.6

19.2

MHz

µA

ppm/°C

Rev. 1.7 100