PIC16F684 Data Sheet 14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology 2004 Microchip Technology Inc. Preliminary DS41202C Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip’s products as critical components in life support systems is not authorized except with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, Accuron, dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, PowerSmart, rfPIC, and SmartShunt are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. AmpLab, FilterLab, MXDEV, MXLAB, PICMASTER, SEEVAL, SmartSensor and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, rfLAB, rfPICDEM, Select Mode, Smart Serial, SmartTel and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2004, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received ISO/TS-16949:2002 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona and Mountain View, California in October 2003. The Company’s quality system processes and procedures are for its PICmicro® 8-bit MCUs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified. DS41202C-page ii Preliminary 2004 Microchip Technology Inc. PIC16F684 14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology High-Performance RISC CPU: Low-Power Features: • Only 35 instructions to learn: - All single-cycle instructions except branches • Operating speed: - DC – 20 MHz oscillator/clock input - DC – 200 ns instruction cycle • Interrupt capability • 8-level deep hardware stack • Direct, Indirect and Relative Addressing modes • Standby Current: - 1 nA @ 2.0V, typical • Operating Current: - 8.5 µA @ 32 kHz, 2.0V, typical - 100 µA @ 1 MHz, 2.0V, typical • Watchdog Timer Current: - 1 µA @ 2.0V, typical Peripheral Features: Special Microcontroller Features: • 12 I/O pins with individual direction control: - High current source/sink for direct LED drive - Interrupt-on-pin change - Individually programmable weak pull-ups - Ultra Low-power Wake-up (ULPWU) • Analog comparator module with: - Two analog comparators - Programmable on-chip voltage reference (CVREF) module (% of VDD) - Comparator inputs and outputs externally accessible • A/D Converter: - 10-bit resolution and 8 channels • Timer0: 8-bit timer/counter with 8-bit programmable prescaler • Enhanced Timer1: - 16-bit timer/counter with prescaler - External Gate Input mode - Option to use OSC1 and OSC2 in LP mode as Timer1 oscillator if INTOSC mode selected • Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler • Enhanced Capture, Compare, PWM module: - 16-bit Capture, max resolution 12.5 ns - Compare, max resolution 200 ns - 10-bit PWM with 1, 2 or 4 output channels, programmable “dead time”, max frequency 20 kHz • In-Circuit Serial ProgrammingTM (ICSPTM) via two pins • Precision Internal Oscillator: - Factory calibrated to ±1% - Software selectable frequency range of 8 MHz to 31 kHz - Software tunable - Two-speed Start-up mode - Crystal fail detect for critical applications - Clock mode switching during operation for power savings • Power-saving Sleep mode • Wide operating voltage range (2.0V-5.5V) • Industrial and Extended Temperature range • Power-on Reset (POR) • Power-up Timer (PWRT) and Oscillator Start-up Timer (OST) • Brown-out Detect (BOD) with software control option • Enhanced low-current Watchdog Timer (WDT) with on-chip oscillator (software selectable nominal 268 seconds with full prescaler) with software enable • Multiplexed Master Clear with pull-up/input pin • Programmable code protection • High Endurance Flash/EEPROM cell: - 100,000 write Flash endurance - 1,000,000 write EEPROM endurance - Flash/Data EEPROM retention: > 40 years Device PIC16F684 Program Memory Data Memory Flash (words) SRAM (bytes) EEPROM (bytes) 2048 128 256 2004 Microchip Technology Inc. I/O 10-bit A/D (ch) Comparators Timers 8/16-bit 12 8 2 2/1 Preliminary DS41202C-page 1 PIC16F684 Pin Diagram 14-pin PDIP, SOIC, TSSOP DS41202C-page 2 1 2 3 4 5 6 7 PIC16F684 VDD RA5/T1CKI/OSC1/CLKIN RA4/AN3/T1G/OSC2/CLKOUT RA3/MCLR/VPP RC5/CCP1/P1A RC4/C2OUT/P1B RC3/AN7/P1C 14 13 12 11 10 9 8 Preliminary VSS RA0/AN0/C1IN+/ICSPDAT/ULPWU RA1/AN1/C1IN-/VREF/ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RC0/AN4/C2IN+ RC1/AN5/C2INRC2/AN6/P1D 2004 Microchip Technology Inc. PIC16F684 Table of Contents 1.0 Device Overview ......................................................................................................................................................................... 5 2.0 Memory Organization .................................................................................................................................................................. 7 3.0 Clock Sources ........................................................................................................................................................................... 19 4.0 I/O Ports .................................................................................................................................................................................... 31 5.0 Timer0 Module .......................................................................................................................................................................... 45 6.0 Timer1 Module with Gate Control.............................................................................................................................................. 49 7.0 Timer2 Module .......................................................................................................................................................................... 53 8.0 Comparator Module................................................................................................................................................................... 55 9.0 Analog-to-Digital Converter (A/D) Module................................................................................................................................. 63 10.0 Data EEPROM Memory ............................................................................................................................................................ 71 11.0 Enhanced Capture/Compare/PWM (ECCP) Module................................................................................................................. 75 12.0 Special Features of the CPU..................................................................................................................................................... 91 13.0 Instruction Set Summary ......................................................................................................................................................... 111 14.0 Development Support.............................................................................................................................................................. 121 15.0 Electrical Specifications........................................................................................................................................................... 127 16.0 DC and AC Characteristics Graphs and Tables...................................................................................................................... 147 17.0 Packaging Information............................................................................................................................................................. 149 Appendix A: Data Sheet Revision History......................................................................................................................................... 153 Appendix B: Migrating from other PICmicro® Devices ..................................................................................................................... 153 Index ................................................................................................................................................................................................. 155 On-Line Support................................................................................................................................................................................ 159 Systems Information and Upgrade Hot Line ..................................................................................................................................... 159 Reader Response ............................................................................................................................................................................. 160 Product Identification System ........................................................................................................................................................... 161 TO OUR VALUED CUSTOMERS It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and enhanced as new volumes and updates are introduced. If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via E-mail at [email protected] or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We welcome your feedback. Most Current Data Sheet To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at: http://www.microchip.com You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page. The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000). Errata An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision of silicon and revision of document to which it applies. To determine if an errata sheet exists for a particular device, please check with one of the following: • Microchip’s Worldwide Web site; http://www.microchip.com • Your local Microchip sales office (see last page) • The Microchip Corporate Literature Center; U.S. FAX: (480) 792-7277 When contacting a sales office or the literature center, please specify which device, revision of silicon and data sheet (include literature number) you are using. Customer Notification System Register on our web site at www.microchip.com/cn to receive the most current information on all of our products. 2004 Microchip Technology Inc. Preliminary DS41202C-page 3 PIC16F684 NOTES: DS41202C-page 4 Preliminary 2004 Microchip Technology Inc. PIC16F684 1.0 DEVICE OVERVIEW The reference manual should be considered a complementary document to this data sheet and is highly recommended reading for a better understanding of the device architecture and operation of the peripheral modules. This document contains device specific information for the PIC16F684. Additional information may be found in the “PICmicro® Mid-Range MCU Family Reference Manual” (DS33023), which may be obtained from your local Microchip Sales Representative or downloaded from the Microchip web site. FIGURE 1-1: The PIC16F684 is covered by this data sheet. It is available in 14-pin PDIP, SOIC and TSSOP packages. Figure 1-1 shows a block diagram of the PIC16F684 device. Table 1-1 shows the pinout description. PIC16F684 BLOCK DIAGRAM INT Configuration 13 Flash 2k X 14 Program Memory Program Bus 8 Data Bus Program Counter PORTA RA0 RA1 8-Level Stack (13-Bit) 14 RA2 RAM 128 Bytes File Registers RAM Addr RA3 RA4 RA5 9 Addr MUX Instruction Reg 7 Direct Addr 8 PORTC Indirect Addr RC0 RC1 FSR Reg RC2 RC3 Status Reg 8 RC4 RC5 3 MUX Power-up Timer Instruction Decode & Control OSC1/CLKIN Oscillator Start-up Timer Power-on Reset Timing Generation ALU 8 Watchdog Timer Brown-out Detect OSC2/CLKOUT Internal Oscillator Block W Reg CCP1/P1A P1B P1C P1D T1G MCLR VDD VSS T1CKI Timer0 Timer1 Timer2 ECCP T0CKI Analog-To-Digital Converter 2 Analog Comparators and Reference EEDATA 256 Bytes 8 Data EEPROM EEADDR VREF AN0 AN1 AN2 AN3 AN4 AN5 AN6 AN7 C1IN- C1IN+ C1OUT C2IN- C2IN+ C2OUT 2004 Microchip Technology Inc. Preliminary DS41202C-page 5 PIC16F684 TABLE 1-1: PIC16F684 PINOUT DESCRIPTION Name Function Input Type Output Type Description RA0/AN0/C1IN+/ICSPDAT/ULPWU RA0 TTL CMOS PORTA I/O w/programmable pull-up and interrupt-on-change AN0 AN — A/D Channel 0 input C1IN+ AN — Comparator 1 input ICSPDAT TTL CMOS ULPWU AN — RA1 TTL CMOS RA1/AN1/C1IN-/VREF/ICSPCLK RA2/AN2/T0CKI/INT/C1OUT RA3/MCLR/VPP RA4/AN3/T1G/OSC2/CLKOUT RA5/T1CKI/OSC1/CLKIN RC0/AN4/C2IN+ RC1/AN5/C2IN- RC2/AN6/P1D RC3/AN7/P1C RC4/C2OUT/P1B Serial Programming Data I/O Ultra Low-power Wake-up input PORTA I/O w/programmable pull-up and interrupt-on-change AN1 AN — A/D Channel 1 input C1IN- AN — Comparator 1 input VREF AN — External Voltage Reference for A/D ICSPCLK ST — Serial Programming Clock RA2 ST CMOS PORTA I/O w/programmable pull-up and interrupt-on-change AN2 AN — A/D Channel 2 input T0CKI ST — Timer0 clock input INT ST — C1OUT — CMOS RA3 TTL — External Interrupt Comparator 1 output PORTA input with interrupt-on-change MCLR ST — Master Clear w/internal pull-up VPP HV — Programming voltage RA4 TTL CMOS AN3 AN — T1G ST — OSC2 — XTAL PORTA I/O w/programmable pull-up and interrupt-on-change A/D Channel 3 input Timer1 gate Crystal/Resonator CLKOUT — CMOS FOSC/4 output RA5 TTL CMOS PORTA I/O w/programmable pull-up and interrupt-on-change T1CKI ST — OSC1 XTAL — Crystal/Resonator CLKIN ST — External clock input/RC oscillator connection RC0 TTL CMOS AN4 AN — A/D Channel 4 input Comparator 2 input Timer1 clock PORTC I/O C2IN+ AN — RC1 TTL CMOS AN5 AN — A/D Channel 5 input Comparator 2 input C2IN- AN — RC2 TTL CMOS AN6 AN — P1D — CMOS RC3 TTL CMOS AN7 AN — PORTC I/O PORTC I/O A/D Channel 6 input PWM output PORTC I/O A/D Channel 7 input P1C — CMOS RC4 TTL CMOS PWM output PORTC I/O C2OUT — CMOS Comparator 2 output P1B — CMOS PWM output RC5 TTL CMOS PORTC I/O CCP1 ST CMOS Capture input/Compare output P1A — CMOS PWM output VSS VSS Power — Ground reference VDD VDD Power — Positive supply RC5/CCP1/P1A Legend: TTL = TTL input buffer, ST = Schmitt Trigger input buffer, AN = Analog input DS41202C-page 6 Preliminary 2004 Microchip Technology Inc. PIC16F684 2.0 MEMORY ORGANIZATION 2.1 Program Memory Organization 2.2 The PIC16F684 has a 13-bit program counter capable of addressing an 8k x 14 program memory space. Only the first 2k x 14 (0000h-07FFh) for the PIC16F684 is physically implemented. Accessing a location above these boundaries will cause a wrap around within the first 2k x 14 space. The Reset vector is at 0000h and the interrupt vector is at 0004h (see Figure 2-1). FIGURE 2-1: PROGRAM MEMORY MAP AND STACK FOR THE PIC16F684 CALL, RETURN RETFIE, RETLW The data memory (see Figure 2-2) is partitioned into two banks, which contain the General Purpose Registers (GPR) and the Special Function Registers (SFR). The Special Function Registers are located in the first 32 locations of each bank. Register locations 20h-7Fh in Bank 0 and A0h-BFh in Bank 1 are General Purpose Registers, implemented as static RAM. Register locations F0h-FFh in Bank 1 point to addresses 70h-7Fh in Bank 0. All other RAM is unimplemented and returns ‘0’ when read. RP0 (Status<5>) is the bank select bit. RP0 = 0: → Bank 0 is selected RP0 = 1: → Bank 1 is selected Note: PC<12:0> Data Memory Organization 13 The IRP and RP1 bits Status<7:6> are reserved and should always be maintained as ‘0’s. Stack Level 1 Stack Level 2 Stack Level 8 Reset Vector 000h Interrupt Vector 0004 0005 On-chip Program Memory 07FFh 0800h 1FFFh 2004 Microchip Technology Inc. Preliminary DS41202C-page 7 PIC16F684 2.2.1 GENERAL PURPOSE REGISTER FILE FIGURE 2-2: The register file is organized as 128 x 8 in the PIC16F684. Each register is accessed, either directly or indirectly, through the File Select Register (FSR) (see Section 2.4 “Indirect Addressing, INDF and FSR Registers”). 2.2.2 SPECIAL FUNCTION REGISTERS The Special Function Registers are registers used by the CPU and peripheral functions for controlling the desired operation of the device (see Table 2-1). These registers are static RAM. The special registers can be classified into two sets: core and peripheral. The Special Function Registers associated with the “core” are described in this section. Those related to the operation of the peripheral features are described in the section of that peripheral feature. DATA MEMORY MAP OF THE PIC16F684 File Address Indirect Addr.(1) File Address 00h Indirect Addr.(1) 80h TMR0 01h OPTION_REG 81h PCL 02h PCL 82h STATUS 03h STATUS 83h FSR 04h FSR 84h PORTA 05h TRISA 85h 06h PORTC 86h TRISC 07h 08h 87h 88h 09h 89h PCLATH 0Ah PCLATH 8Ah INTCON 0Bh INTCON 8Bh PIR1 0Ch PIE1 8Ch 0Dh 8Dh TMR1L 0Eh PCON 8Eh TMR1H 0Fh OSCCON 8Fh T1CON 10h OSCTUNE 90h TMR2 11h ANSEL 91h T2CON CCPR1L 12h PR2 92h CCPR1H 14h CCP1CON 15h WPUA 95h PWM1CON 16h IOCA 96h ECCPAS 17h WDTCON 18h CMCON0 19h VRCON 99h CMCON1 1Ah EEDAT 9Ah 1Bh EEADR 9Bh 1Ch EECON1 9Ch 1Dh EECON2(1) 9Dh ADRESH 1Eh ADRESL 9Eh ADCON0 1Fh ADCON1 General Purpose Registers 32 Bytes 9Fh A0h 13h 20h General Purpose Registers 93h 94h 97h 98h BFh 96 Bytes ACCESSES 70h-7Fh 7Fh BANK 0 F0h FFh BANK 1 Unimplemented data memory locations, read as ‘0’. Note 1: DS41202C-page 8 Preliminary Not a physical register. 2004 Microchip Technology Inc. PIC16F684 TABLE 2-1: Addr Name PIC16F684 SPECIAL REGISTERS SUMMARY BANK 0 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOD Page Bank 0 00h INDF Addressing this location uses contents of FSR to address data memory (not a physical register) xxxx xxxx 17, 99 01h TMR0 Timer0 Module’s register xxxx xxxx 45, 99 02h PCL Program Counter’s (PC) Least Significant Byte 0000 0000 17, 99 03h STATUS 04h FSR 05h PORTA 06h — 07h IRP(1) RP1(1) RP0 TO PD Z DC C Indirect Data Memory Address Pointer PORTC — — RA5 RA4 RA3 RA2 RA1 RA0 Unimplemented — — RC5 RC4 RC3 RC2 RC1 RC0 0001 1xxx 11, 99 xxxx xxxx 17, 99 --xx xxxx 31, 99 — — --xx xxxx 40, 99 — 08h — Unimplemented — 09h — Unimplemented — — ---0 0000 17, 99 0Ah PCLATH 0Bh INTCON GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 13, 99 0Ch PIR1 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF TMR1IF 0000 0000 15, 99 0Dh — 0Eh TMR1L 0Fh TMR1H 10h T1CON 11h TMR2 12h T2CON 13h CCPR1L 14h CCPR1H 15h CCP1CON — — — Write Buffer for upper 5 bits of Program Counter Unimplemented — — Holding Register for the Least Significant Byte of the 16-bit TMR1 xxxx xxxx 49, 99 Holding Register for the Most Significant Byte of the 16-bit TMR1 xxxx xxxx 49, 99 51, 99 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0000 0000 0000 0000 53, 99 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 53, 99 Capture/Compare/PWM Register 1 Low Byte XXXX XXXX 75, 99 Capture/Compare/PWM Register 1 High Byte XXXX XXXX 75, 99 CCP1M0 0000 0000 75, 99 PDC0 0000 0000 85, 99 T1GINV TMR1GE Timer2 Module register — TOUTPS3 P1M1 P1M0 16h PWM1CON 17h ECCPAS 18h WDTCON — 19h CMCON0 C2OUT 1Ah CMCON1 — — DC1B1 DC1B0 CCP1M3 PDC3 CCP1M2 CCP1M1 PRSEN PDC6 PDC5 PDC4 PDC2 PDC1 ECCPASE ECCPAS2 ECCPAS1 ECCPAS0 PSSAC1 PSSAC0 PSSBD1 PSSBD0 0000 0000 86, 99 — — WDTPS3 WDTPS2 WDTPS1 WDTPS0 SWDTEN ---0 1000 106, 99 C1OUT C2INV C1INV CIS CM2 CM1 CM0 0000 0000 55, 99 — — — — T1GSS C2SYNC ---- --10 59, 99 1Bh — Unimplemented — — 1Ch — Unimplemented — — 1Dh — Unimplemented — — xxxx xxxx 65, 99 00-0 0000 66, 99 1Eh ADRESH 1Fh ADCON0 Legend: Note 1: Most Significant 8 bits of the left shifted A/D result or 2 bits of right shifted result ADFM VCFG — CHS2 CHS1 CHS0 GO/DONE ADON — = Unimplemented locations read as ‘0’, u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented IRP and RP1 bits are reserved, always maintain these bits clear. 2004 Microchip Technology Inc. Preliminary DS41202C-page 9 PIC16F684 TABLE 2-2: Addr PIC16F684 SPECIAL FUNCTION REGISTERS SUMMARY BANK 1 Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOD Page xxxx xxxx 17, 99 Bank 1 80h INDF 81h OPTION_REG 82h PCL 83h STATUS 84h FSR 85h TRISA RAPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 Program Counter’s (PC) Least Significant Byte IRP(1) RP1(1) RP0 TO PD Z DC C Indirect Data Memory Address Pointer 86h 87h Addressing this location uses contents of FSR to address data memory (not a physical register) — TRISC — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 Unimplemented — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 1111 1111 12, 99 0000 0000 17, 99 0001 1xxx 11, 99 xxxx xxxx 17, 99 --11 1111 32, 99 — — --11 1111 43, 99 — 88h — Unimplemented — 89h — Unimplemented — — 8Ah PCLATH ---0 0000 17, 99 — — — Write Buffer for upper 5 bits of Program Counter 8Bh INTCON GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 13, 99 8Ch PIE1 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE TMR1IE 0000 0000 14, 99 — — — POR BOD --01 --qq 16, 99 8Dh 8Eh — Unimplemented PCON — — ULPWUE SBODEN — 8Fh OSCCON — IRCF2 IRCF1 IRCF0 OSTS(2) HTS LTS SCS -110 x000 29, 99 90h OSCTUNE — — — TUN4 TUN3 TUN2 TUN1 TUN0 ---0 0000 23, 99 ANS7 ANS6 ANS5 ANS4 ANS3 ANS2 ANS1 ANS0 91h ANSEL 92h PR2 Timer2 Module Period Register 1111 1111 65, 99 1111 1111 53, 99 — 93h — Unimplemented — 94h — Unimplemented — — 95h WPUA(3) 96h IOCA — — WPUA5 WPUA4 — WPUA2 WPUA1 WPUA0 --11 -111 32, 100 — — IOCA5 IOCA4 IOCA3 IOCA2 IOCA1 IOCA0 --00 0000 33, 100 97h — Unimplemented — — 98h — Unimplemented — — 99h VRCON 0-0- 0000 62, 100 VREN — VRR — VR3 VR2 VR1 VR0 9Ah EEDAT EEDAT7 EEDAT6 EEDAT5 EEDAT4 EEDAT3 EEDAT2 EEDAT1 EEDAT0 0000 0000 71, 100 9Bh EEADR EEADR7 EEADR6 EEADR5 EEADR4 EEADR3 EEADR2 EEADR1 EEADR0 0000 0000 71, 100 9Ch EECON1 — — — — WRERR WREN WR RD 9Dh EECON2 EEPROM Control Register 2 (not a physical register) 9Eh ADRESL Least Significant 2 bits of the left shifted result or 8 bits of the right shifted result 9Fh ADCON1 Legend: Note 1: 2: 3: — ADCS2 ADCS1 ADCS0 — — — — ---- x000 72, 100 ---- ---- 72, 100 xxxx xxxx 65, 100 -000 ---- 66, 100 — = Unimplemented locations read as ‘0’, u = unchanged, x = unknown, q = value depends on condition, shaded = unimplemented IRP and RP1 bits are reserved, always maintain these bits clear. OSTS bit OSCCON <3> reset to ‘0’ with Dual Speed Start-up and LP, HS or XT selected as the oscillator. RA3 pull-up is enabled when MCLRE is ‘1’ in the Configuration Word register. DS41202C-page 10 Preliminary 2004 Microchip Technology Inc. PIC16F684 2.2.2.1 Status Register The Status register, shown in Register 2-1, contains: • the arithmetic status of the ALU • the Reset status • the bank select bits for data memory (SRAM) The Status register can be the destination for any instruction, like any other register. If the Status register is the destination for an instruction that affects the Z, DC or C bits, then the write to these three bits is disabled. These bits are set or cleared according to the device logic. Furthermore, the TO and PD bits are not writable. Therefore, the result of an instruction with the Status register as destination may be different than intended. REGISTER 2-1: For example, CLRF STATUS, will clear the upper three bits and set the Z bit. This leaves the Status register as ‘000u u1uu’ (where u = unchanged). It is recommended, therefore, that only BCF, BSF, SWAPF and MOVWF instructions are used to alter the Status register, because these instructions do not affect any Status bits. For other instructions not affecting any Status bits, see the “Instruction Set Summary”. Note 1: Bits IRP and RP1 (Status<7:6>) are not used by the PIC16F684 and should be maintained as clear. Use of these bits is not recommended, since this may affect upward compatibility with future products. 2: The C and DC bits operate as a Borrow and Digit Borrow out bit, respectively, in subtraction. See the SUBLW and SUBWF instructions for examples. STATUS – STATUS REGISTER (ADDRESS: 03h OR 83h) Reserved Reserved IRP RP1 R/W-0 R-1 R-1 R/W-x R/W-x R/W-x RP0 TO PD Z DC C bit 7 bit 0 bit 7 IRP: This bit is reserved and should be maintained as ‘0’ bit 6 RP1: This bit is reserved and should be maintained as ‘0’ bit 5 RP0: Register Bank Select bit (used for direct addressing) 1 = Bank 1 (80h – FFh) 0 = Bank 0 (00h – 7Fh) bit 4 TO: Time-out bit 1 = After power-up, CLRWDT instruction or SLEEP instruction 0 = A WDT time-out occurred bit 3 PD: Power-down bit 1 = After power-up or by the CLRWDT instruction 0 = By execution of the SLEEP instruction bit 2 Z: Zero bit 1 = The result of an arithmetic or logic operation is zero 0 = The result of an arithmetic or logic operation is not zero bit 1 DC: Digit carry/borrow bit (ADDWF, ADDLW,SUBLW,SUBWF instructions) For borrow, the polarity is reversed. 1 = A carry-out from the 4th low-order bit of the result occurred 0 = No carry-out from the 4th low-order bit of the result bit 0 C: Carry/borrow bit (ADDWF, ADDLW, SUBLW, SUBWF instructions) 1 = A carry-out from the Most Significant bit of the result occurred 0 = No carry-out from the Most Significant bit of the result occurred Note 1: For borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order bit of the source register. Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 11 PIC16F684 2.2.2.2 Option Register Note: The Option register is a readable and writable register, which contains various control bits to configure: • • • • TMR0/WDT prescaler External RA2/INT interrupt TMR0 Weak pull-ups on PORTA REGISTER 2-2: To achieve a 1:1 prescaler assignment for TMR0, assign the prescaler to the WDT by setting PSA bit to ‘1’ (OPTION_REG<3>). See Section 5.4 “Prescaler”. OPTION_REG – OPTION REGISTER (ADDRESS: 81h) R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 RAPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 bit 7 bit 0 bit 7 RAPU: PORTA Pull-up Enable bit 1 = PORTA pull-ups are disabled 0 = PORTA pull-ups are enabled by individual port latch values bit 6 INTEDG: Interrupt Edge Select bit 1 = Interrupt on rising edge of RA2/INT pin 0 = Interrupt on falling edge of RA2/INT pin bit 5 T0CS: TMR0 Clock Source Select bit 1 = Transition on RA2/T0CKI pin 0 = Internal instruction cycle clock (CLKOUT) bit 4 T0SE: TMR0 Source Edge Select bit 1 = Increment on high-to-low transition on RA2/T0CKI pin 0 = Increment on low-to-high transition on RA2/T0CKI pin bit 3 PSA: Prescaler Assignment bit 1 = Prescaler is assigned to the WDT 0 = Prescaler is assigned to the Timer0 module bit 2-0 PS<2:0>: Prescaler Rate Select bits BIT VALUE 000 001 010 011 100 101 110 111 TMR0 RATE WDT RATE 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256 1:1 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128 Legend: DS41202C-page 12 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 2.2.2.3 INTCON Register Note: The INTCON register is a readable and writable register, which contains the various enable and flag bits for TMR0 register overflow, PORTA change and external RA2/INT pin interrupts. REGISTER 2-3: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit, GIE (INTCON<7>). User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. INTCON – INTERRUPT CONTROL REGISTER (ADDRESS: 0Bh OR 8Bh) R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 GIE PEIE T0IE INTE RAIE T0IF INTF RAIF bit 7 bit 0 bit 7 GIE: Global Interrupt Enable bit 1 = Enables all unmasked interrupts 0 = Disables all interrupts bit 6 PEIE: Peripheral Interrupt Enable bit 1 = Enables all unmasked peripheral interrupts 0 = Disables all peripheral interrupts bit 5 T0IE: TMR0 Overflow Interrupt Enable bit 1 = Enables the TMR0 interrupt 0 = Disables the TMR0 interrupt bit 4 INTE: RA2/INT External Interrupt Enable bit 1 = Enables the RA2/INT external interrupt 0 = Disables the RA2/INT external interrupt bit 3 RAIE: PORTA Change Interrupt Enable bit(1) 1 = Enables the PORTA change interrupt 0 = Disables the PORTA change interrupt bit 2 T0IF: TMR0 Overflow Interrupt Flag bit(2) 1 = TMR0 register has overflowed (must be cleared in software) 0 = TMR0 register did not overflow bit 1 INTF: RA2/INT External Interrupt Flag bit 1 = The RA2/INT external interrupt occurred (must be cleared in software) 0 = The RA2/INT external interrupt did not occur bit 0 RAIF: PORTA Change Interrupt Flag bit 1 = When at least one of the PORTA <5:0> pins changed state (must be cleared in software) 0 = None of the PORTA <5:0> pins have changed state Note 1: IOCA register must also be enabled. 2: T0IF bit is set when Timer0 rolls over. Timer0 is unchanged on Reset and should be initialized before clearing T0IF bit. Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 13 PIC16F684 2.2.2.4 PIE1 Register The PIE1 register contains the interrupt enable bits, as shown in Register 2-4. REGISTER 2-4: Note: Bit PEIE (INTCON<6>) must be set to enable any peripheral interrupt. PIE1 – PERIPHERAL INTERRUPT ENABLE REGISTER 1 (ADDRESS: 8Ch) R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE TMR1IE bit 7 bit 0 bit 7 EEIE: EE Write Complete Interrupt Enable bit 1 = Enables the EE write complete interrupt 0 = Disables the EE write complete interrupt bit 6 ADIE: A/D Converter Interrupt Enable bit 1 = Enables the A/D converter interrupt 0 = Disables the A/D converter interrupt bit 5 CCP1IE: CCP1 Interrupt Enable bit 1 = Enables the CCP1 interrupt 0 = Disables the CCP1 interrupt bit 4 C2IE: Comparator 2 Interrupt Enable bit 1 = Enables the Comparator 2 interrupt 0 = Disables the Comparator 2 interrupt bit 3 C1IE: Comparator 1 Interrupt Enable bit 1 = Enables the Comparator 1 interrupt 0 = Disables the Comparator 1 interrupt bit 2 OSFIE: Oscillator Fail Interrupt Enable bit 1 = Enables the oscillator fail interrupt 0 = Disables the oscillator fail interrupt bit 1 TMR2IE: Timer2 to PR2 Match Interrupt Enable bit 1 = Enables the Timer2 to PR2 match interrupt 0 = Disables the Timer2 to PR2 match interrupt bit 0 TMR1IE: Timer1 Overflow Interrupt Enable bit 1 = Enables the Timer1 overflow interrupt 0 = Disables the Timer1 overflow interrupt Legend: DS41202C-page 14 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 2.2.2.5 PIR1 Register The PIR1 register contains the interrupt flag bits, as shown in Register 2-5. REGISTER 2-5: Note: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit, GIE (INTCON<7>). User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. PIR1 – PERIPHERAL INTERRUPT REQUEST REGISTER 1 (ADDRESS: 0Ch) R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF TMR1IF bit 7 bit 0 bit 7 EEIF: EEPROM Write Operation Interrupt Flag bit 1 = The write operation completed (must be cleared in software) 0 = The write operation has not completed or has not been started bit 6 ADIF: A/D Interrupt Flag bit 1 = A/D conversion complete 0 = A/D conversion has not completed or has not been started bit 5 CCP1IF: CCP1 Interrupt Flag bit Capture mode: 1 = A TMR1 register capture occurred (must be cleared in software) 0 = No TMR1 register capture occurred Compare mode: 1 = A TMR1 register compare match occurred (must be cleared in software) 0 = No TMR1 register compare match occurred PWM mode: Unused in this mode bit 4 C2IF: Comparator 2 Interrupt Flag bit 1 = Comparator 2 output has changed (must be cleared in software) 0 = Comparator 2 output has not changed bit 3 C1IF: Comparator 1 Interrupt Flag bit 1 = Comparator 1 output has changed (must be cleared in software) 0 = Comparator 1 output has not changed bit 2 OSFIF: Oscillator Fail Interrupt Flag bit 1 = System oscillator failed, clock input has changed to INTOSC (must be cleared in software) 0 = System clock operating bit 1 TMR2IF: Timer2 to PR2 Match Interrupt Flag bit 1 = Timer2 to PR2 match occurred (must be cleared in software) 0 = Timer2 to PR2 match has not occurred bit 0 TMR1IF: Timer1 Overflow Interrupt Flag bit 1 = Timer1 register overflowed (must be cleared in software) 0 = Timer1 has not overflowed Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 15 PIC16F684 2.2.2.6 PCON Register The Power Control (PCON) register (see Table 12-2) contains flag bits to differentiate between a: • • • • Power-on Reset (POR) Brown-out Detect (BOD) Watchdog Timer Reset (WDT) External MCLR Reset The PCON register also controls the ultra low-power wake-up and software enable of the BOD. The PCON register bits are shown in Register 2-6. REGISTER 2-6: PCON – POWER CONTROL REGISTER (ADDRESS: 8Eh) U-0 U-0 — — R/W-0 R/W-1 ULPWUE SBODEN U-0 U-0 R/W-0 R/W-x — — POR BOD bit 7 bit 0 bit 7-6 Unimplemented: Read as ‘0’ bit 5 ULPWUE: Ultra Low-Power Wake-up Enable bit 1 = Ultra low-power wake-up enabled 0 = Ultra low-power wake-up disabled bit 4 SBODEN: Software BOD Enable bit(1) 1 = BOD enabled 0 = BOD disabled bit 3-2 Unimplemented: Read as ‘0’ bit 1 POR: Power-on Reset Status bit 1 = No Power-on Reset occurred 0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs) bit 0 BOD: Brown-out Detect Status bit 1 = No Brown-out Detect occurred 0 = A Brown-out Detect occurred (must be set in software after a Brown-out Detect occurs) Note 1: BODEN<1:0> = 01 in the Configuration Word register for this bit to control the BOD. Legend: DS41202C-page 16 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 2.3 PCL and PCLATH The Program Counter (PC) is 13 bits wide. The low byte comes from the PCL register, which is a readable and writable register. The high byte (PC<12:8>) is not directly readable or writable and comes from PCLATH. On any Reset, the PC is cleared. Figure 2-3 shows the two situations for the loading of the PC. The upper example in Figure 2-3 shows how the PC is loaded on a write to PCL (PCLATH<4:0> → PCH). The lower example in Figure 2-3 shows how the PC is loaded during a CALL or GOTO instruction (PCLATH<4:3> → PCH). FIGURE 2-3: 12 8 7 0 Instruction with PCL as Destination 8 PCLATH<4:0> ALU Result PCLATH PCH 11 10 PCL 8 0 7 PC GOTO, CALL 2 PCLATH<4:3> 11 OPCODE <10:0> COMPUTED GOTO A computed GOTO is accomplished by adding an offset to the program counter (ADDWF PCL). When performing a table read using a computed GOTO method, care should be exercised if the table location crosses a PCL memory boundary (each 256-byte block). Refer to the Application Note AN556, “Implementing a Table Read” (DS00556). 2.3.2 Indirect Addressing, INDF and FSR Registers The INDF register is not a physical register. Addressing the INDF register will cause indirect addressing. Indirect addressing is possible by using the INDF register. Any instruction using the INDF register actually accesses data pointed to by the File Select Register (FSR). Reading INDF itself indirectly will produce 00h. Writing to the INDF register indirectly results in a no operation (although Status bits may be affected). An effective 9-bit address is obtained by concatenating the 8-bit FSR and the IRP bit (Status<7>), as shown in Figure 2-4. A simple program to clear RAM location 20h-2Fh using indirect addressing is shown in Example 2-1. PCLATH 2.3.1 2: There are no instructions/mnemonics called PUSH or POP. These are actions that occur from the execution of the CALL, RETURN, RETLW and RETFIE instructions or the vectoring to an interrupt address. 2.4 PCL PC 12 Note 1: There are no Status bits to indicate stack overflow or stack underflow conditions. LOADING OF PC IN DIFFERENT SITUATIONS PCH 5 The stack operates as a circular buffer. This means that after the stack has been PUSHed eight times, the ninth push overwrites the value that was stored from the first push. The tenth push overwrites the second push (and so on). EXAMPLE 2-1: INDIRECT ADDRESSING MOVLW0x20;initialize pointer MOVWFFSR ;to RAM NEXT CLRFINDF ;clear INDF register INCFFSR ;INC POINTER BTFSSFSR,4;all done? GOTONEXT ;no clear next CONTINUE ;yes continue STACK The PIC16F684 Family has an 8-level x 13-bit wide hardware stack (see Figure 2-1). The stack space is not part of either program or data space and the stack pointer is not readable or writable. The PC is PUSHed onto the stack when a CALL instruction is executed or an interrupt causes a branch. The stack is POPed in the event of a RETURN, RETLW or a RETFIE instruction execution. PCLATH is not affected by a PUSH or POP operation. 2004 Microchip Technology Inc. Preliminary DS41202C-page 17 PIC16F684 FIGURE 2-4: DIRECT/INDIRECT ADDRESSING PIC16F684 Direct Addressing RP1 (1) RP0 6 Bank Select From Opcode Indirect Addressing IRP(1) 0 7 Bank Select Location Select 00 01 10 File Select Register 0 Location Select 11 00h 180h Data Memory NOT USED 7Fh 1FFh Bank 0 Bank 1 Bank 2 Bank 3 For memory map detail, see Figure 2-2. Note 1: DS41202C-page 18 The RP1 and IRP bits are reserved; always maintain these bits clear. Preliminary 2004 Microchip Technology Inc. PIC16F684 3.0 CLOCK SOURCES The PIC16F684 can be configured in one of eight clock modes. 3.1 Overview 1. 2. The PIC16F684 has a wide variety of clock sources and selection features to allow it to be used in a wide range of applications while maximizing performance and minimizing power consumption. Figure 3-1 illustrates a block diagram of the PIC16F684 clock sources. 3. 4. 5. Clock sources can be configured from external oscillators, quartz crystal resonators, ceramic resonators and Resistor-Capacitor (RC) circuits. In addition, the system clock source can be configured from one of two internal oscillators, with a choice of speeds selectable via software. Additional clock features include: 6. 7. 8. • Selectable system clock source between external or internal via software. • Two-Speed Clock Start-up mode, which minimizes latency between external oscillator start-up and code execution. • Fail-Safe Clock Monitor (FSCM) designed to detect a failure of the external clock source (LP, XT, HS, EC or RC modes) and switch to the internal oscillator. FIGURE 3-1: EC – External clock with I/O on RA4. LP – Low gain Crystal or Ceramic Resonator Oscillator mode. XT – Medium gain Crystal or Ceramic Resonator Oscillator mode. HS – High gain Crystal or Ceramic Resonator mode. RC – External Resistor-Capacitor (RC) with FOSC/4 output on RA4. RCIO – External Resistor-Capacitor with I/O on RA4. INTRC – Internal oscillator with FOSC/4 output on RA4 and I/O on RA5. INTRCIO – Internal oscillator with I/O on RA4 and RA5. Clock source modes are configured by the FOSC<2:0> bits in the Configuration Word register (see Section 12.0 “Special Features of the CPU”). The internal clock can be generated by two oscillators. The HFINTOSC is a high-frequency calibrated oscillator. The LFINTOSC is a low-frequency uncalibrated oscillator. PIC16F684 CLOCK SOURCE BLOCK DIAGRAM FOSC<2:0> (Configuration Word) SCS (OSCCON<0>) External Oscillator OSC2 Sleep IRCF<2:0> (OSCCON<6:4>) 8 MHz Internal Oscillator 4 MHz MUX LP, XT, HS, RC, RCIO, EC OSC1 System Clock (CPU and Peripherals) 111 110 101 1 MHz 100 500 kHz 250 kHz 125 kHz LFINTOSC 31 kHz 31 kHz 011 MUX HFINTOSC 8 MHz Postscaler 2 MHz 010 001 000 Power-up Timer (PWRT) Watchdog Timer (WDT) Fail-Safe Clock Monitor (FSCM) 2004 Microchip Technology Inc. Preliminary DS41202C-page 19 PIC16F684 3.2 Clock Source Modes Clock source modes can be classified as external or internal. External Clock Modes 3.3.1 OSCILLATOR START-UP TIMER (OST) If the PIC16F684 is configured for LP, XT or HS modes, the Oscillator Start-up Timer (OST) counts 1024 oscillations from the OSC1 pin, following a Power-on Reset (POR) and the Power-up Timer (PWRT) has expired (if configured), or a wake-up from Sleep. During this time, the program counter does not increment and program execution is suspended. The OST ensures that the oscillator circuit, using a quartz crystal resonator or ceramic resonator, has started and is providing a stable system clock to the PIC16F684. When switching between clock sources a delay is required to allow the new clock to stabilize. These oscillator delays are shown in Table 3-1. • External clock modes rely on external circuitry for the clock source. Examples are oscillator modules (EC mode), quartz crystal resonators or ceramic resonators (LP, XT and HS modes), and Resistor-Capacitor (RC mode) circuits. • Internal clock sources are contained internally within the PIC16F684. The PIC16F684 has two internal oscillators, the 8 MHz High-Frequency Internal Oscillator (HFINTOSC) and 31 kHz Low-Frequency Internal Oscillator (LFINTOSC). The system clock can be selected between external or internal clock sources via the System Clock Selection (SCS) bit (see Section 3.5 “Clock Switching”). TABLE 3-1: 3.3 In order to minimize latency between external oscillator start-up and code execution, the Two-Speed Clock Start-up mode can be selected (see Section 3.6 “Two-Speed Clock Start-up Mode”). OSCILLATOR DELAY EXAMPLES Switch From Switch To Frequency Sleep/POR LFINTOSC HFINTOSC 31 kHz 125 kHz to 8 MHz Sleep/POR EC, RC DC – 20 MHz LFINTOSC (31 kHz) EC, RC DC – 20 MHz Oscillator Delay 5 µs-10 µs (approx.) CPU Start-up(1) Sleep/POR LP, XT, HS 31 kHz to 20 MHz 1024 Clock Cycles (OST) LFINTOSC (31 kHz) HFINTOSC 125 kHz to 8 MHz 1 µs (approx.) Note 1: The 5 µs to 10 µs start-up delay is based on a 1 MHz system clock. 3.3.2 EC MODE FIGURE 3-2: The External Clock (EC) mode allows an externally generated logic level as the system clock source. When operating in this mode, an external clock source is connected to the OSC1 pin and the RA5 pin is available for general purpose I/O. Figure 3-2 shows the pin connections for EC mode. EXTERNAL CLOCK (EC) MODE OPERATION OSC1/CLKIN Clock from Ext. System PIC16F684 RA4 I/O (OSC2) The Oscillator Start-up Timer (OST) is disabled when EC mode is selected. Therefore, there is no delay in operation after a Power-on Reset (POR) or wake-up from Sleep. Because the PIC16F684 design is fully static, stopping the external clock input will have the effect of halting the device while leaving all data intact. Upon restarting the external clock, the device will resume operation as if no time had elapsed. DS41202C-page 20 Preliminary 2004 Microchip Technology Inc. PIC16F684 3.3.3 FIGURE 3-4: LP, XT, HS MODES The LP, XT and HS modes support the use of quartz crystal resonators or ceramic resonators connected to the OSC1 and OSC2 pins (Figure 3-1). The mode selects a low, medium or high gain setting of the internal inverter-amplifier to support various resonator types and speed. LP Oscillator mode selects the lowest gain setting of the internal inverter-amplifier. LP mode current consumption is the least of the three modes. This mode is best suited to drive resonators with a low drive level specification, for example, tuning fork type crystals. XT Oscillator mode selects the intermediate gain setting of the internal inverter-amplifier. XT mode current consumption is the medium of the three modes. This mode is best suited to drive resonators with a medium drive level specification, for example, low-frequency/AT-cut quartz crystal resonators. HS Oscillator mode selects the highest gain setting of the internal inverter-amplifier. HS mode current consumption is the highest of the three modes. This mode is best suited for resonators that require a high drive setting, for example, high-frequency/AT-cut quartz crystal resonators or ceramic resonators. CERAMIC RESONATOR OPERATION (XT OR HS MODE) PIC16F684 OSC1 C1 To Internal Logic RP(3) RF(2) Sleep OSC2 RS(1) C2 Ceramic Resonator Note 1: A series resistor (RS) may be required for ceramic resonators with low drive level. 2: The value of RF varies with the Oscillator mode selected (typically between 2 MΩ to 10 MΩ). 3: An additional parallel feedback resistor (RP) may be required for proper ceramic resonator operation (typical value 1 MΩ). Figure 3-3 and Figure 3-4 show typical circuits for quartz crystal and ceramic resonators, respectively. FIGURE 3-3: QUARTZ CRYSTAL OPERATION (LP, XT OR HS MODE) PIC16F684 OSC1 C1 To Internal Logic Quartz Crystal OSC2 RF(2) Sleep RS(1) C2 Note 1: A series resistor (RS) may be required for quartz crystals with low drive level. 2: The value of RF varies with the Oscillator mode selected (typically between 2 MΩ to 10 MΩ). Note 1: Quartz crystal characteristics vary according to type, package and manufacturer. The user should consult the manufacturer data sheets for specifications and recommended application. 2: Always verify oscillator performance over the VDD and temperature range that is expected for the application. 2004 Microchip Technology Inc. Preliminary DS41202C-page 21 PIC16F684 3.3.4 EXTERNAL RC MODES 3.4 The External Resistor-Capacitor (RC) modes support the use of an external RC circuit. This allows the designer maximum flexibility in frequency choice while keeping costs to a minimum when clock accuracy is not required. There are two modes, RC and RCIO. In RC mode, the RC circuit connects to the OSC1 pin. The OSC2/CLKOUT pin outputs the RC oscillator frequency divided by 4. This signal may be used to provide a clock for external circuitry, synchronization, calibration, test or other application requirements. Figure 3-5 shows the RC mode connections. FIGURE 3-5: VDD Internal Clock OSC1 CEXT In RCIO mode, the RC circuit is connected to the OSC1 pin. The OSC2 pin becomes an additional general purpose I/O pin. The I/O pin becomes bit 4 of PORTA (RA4). Figure 3-6 shows the RCIO mode connections. RCIO MODE In INTRC mode, the OSC1 pin is available for general purpose I/O. The OSC2/CLKOUT pin outputs the selected internal oscillator frequency divided by 4. The CLKOUT signal may be used to provide a clock for external circuitry, synchronization, calibration, test or other application requirements. In INTRCIO mode, the OSC1 and OSC2 pins are available for general purpose I/O. VDD 3.4.2 REXT Internal Clock OSC1 INTRC AND INTRCIO MODES The INTRC and INTRCIO modes configure the internal oscillators as the system clock source when the device is programmed using the Oscillator Selection (FOSC) bits in the Configuration Word register (Register 12-1). OSC2/CLKOUT FOSC/4 Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ CEXT > 20 pF HFINTOSC The High-Frequency Internal Oscillator (HFINTOSC) is a factory calibrated 8 MHz internal clock source. The frequency of the HFINTOSC can be altered approximately ±12% via software using the OSCTUNE register (Register 3-1). CEXT PIC16F684 RA4 2. The HFINTOSC (High-Frequency Internal Oscillator) is factory calibrated and operates at 8 MHz. The frequency of the HFINTOSC can be user adjusted ±12% via software using the OSCTUNE register (Register 3-1). The LFINTOSC (Low-Frequency Internal Oscillator) is uncalibrated and operates at approximately 31 kHz. 3.4.1 PIC16F684 VSS 1. The system clock can be selected between external or internal clock sources via the System Clock Selection (SCS) bit (see Section 3.5 “Clock Switching”). REXT FIGURE 3-6: The PIC16F684 has two independent, internal oscillators that can be configured or selected as the system clock source. The system clock speed can be selected via software using the Internal Oscillator Frequency Select (IRCF) bits. RC MODE VSS Internal Clock Modes I/O (OSC2) Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ CEXT > 20 pF The RC oscillator frequency is a function of the supply voltage, the resistor (REXT) and capacitor (CEXT) values and the operating temperature. Other factors affecting the oscillator frequency are: • threshold voltage variation • component tolerances • packaging variations in capacitance The output of the HFINTOSC connects to a postscaler and multiplexer (see Figure 3-1). One of seven frequencies can be selected via software using the IRCF bits (see Section 3.4.4 “Frequency Select Bits (IRCF)”). The HFINTOSC is enabled by selecting any frequency between 8 MHz and 125 kHz (IRCF ≠ 000) as the system clock source (SCS = 1), or when Two-Speed Start-up is enabled (IESO = 1 and IRCF ≠ 000). The HF Internal Oscillator (HTS) bit (OSCCON<2>) indicates whether the HFINTOSC is stable or not. The user also needs to take into account variation due to tolerance of external RC components used. DS41202C-page 22 Preliminary 2004 Microchip Technology Inc. PIC16F684 3.4.2.1 OSCTUNE Register The HFINTOSC is factory calibrated but can be adjusted in software by writing to the OSCTUNE register (Register 3-1). The OSCTUNE register has a tuning range of ±12%. The default value of the OSCTUNE register is ‘0’. The value is a 5-bit two’s complement number. Due to process variation, the monotonicity and frequency step cannot be specified. REGISTER 3-1: When the OSCTUNE register is modified, the HFINTOSC frequency will begin shifting to the new frequency. The HFINTOSC clock will stabilize within 1 ms. Code execution continues during this shift. There is no indication that the shift has occurred. OSCTUNE does not affect the LFINTOSC frequency. Operation of features that depend on the LFINTOSC clock source frequency, such as the Power-up Timer (PWRT), Watchdog Timer (WDT), Fail-Safe Clock Monitor (FSCM) and peripherals, are not affected by the change in frequency. OSCTUNE – OSCILLATOR TUNING RESISTOR (ADDRESS: 90h) U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 — — — TUN4 TUN3 TUN2 TUN1 TUN0 bit 7 bit 0 bit 7-5 Unimplemented: Read as ‘0’ bit 4-0 TUN<4:0>: Frequency Tuning bits 01111 = Maximum frequency 01110 = • • • 00001 = 00000 = Oscillator module is running at the calibrated frequency. 11111 = • • • 10000 = Minimum frequency Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 23 PIC16F684 3.4.3 LFINTOSC 3.4.5 The Low-Frequency Internal Oscillator (LFINTOSC) is an uncalibrated (approximate) 31 kHz internal clock source. The output of the LFINTOSC connects to a postscaler and multiplexer (see Figure 3-1). 31 kHz can be selected via software using the IRCF bits (see Section 3.4.4 “Frequency Select Bits (IRCF)”). The LFINTOSC is also the frequency for the Power-up Timer (PWRT), Watchdog Timer (WDT) and Fail-Safe Clock Monitor (FSCM). The LFINTOSC is enabled by selecting 31 kHz (IRCF = 000) as the system clock source (SCS = 1), or when any of the following are enabled: • • • • Two-Speed Start-up (IESO = 1 and IRCF = 000) Power-up Timer (PWRT) Watchdog Timer (WDT) Fail-Safe Clock Monitor (FSCM) 3.4.4 1. 2. 3. 5. FREQUENCY SELECT BITS (IRCF) The output of the 8 MHz HFINTOSC and 31 kHz LFINTOSC connects to a postscaler and multiplexer (see Figure 3-1). The Internal Oscillator Frequency select bits, IRCF<2:0> (OSCCON<6:4>), select the frequency output of the internal oscillators. One of eight frequencies can be selected via software: • • • • • • • • When switching between the LFINTOSC and the HFINTOSC, the new oscillator may already be shut down to save power. If this is the case, there is a 10 µs delay after the IRCF bits are modified before the frequency selection takes place. The LTS/HTS bits will reflect the current active status of the LFINTOSC and the HFINTOSC oscillators. The timing of a frequency selection is as follows: 4. The LF Internal Oscillator (LTS) bit (OSCCON<1>) indicates whether the LFINTOSC is stable or not. HF AND LF INTOSC CLOCK SWITCH TIMING 6. IRCF bits are modified. If the new clock is shut down, a 10 µs clock start-up delay is started. Clock switch circuitry waits for a falling edge of the current clock. CLKOUT is held low and the clock switch circuitry waits for a rising edge in the new clock. CLKOUT is now connected with the new clock. HTS/LTS bits are updated as required. Clock switch is complete. If the internal oscillator speed selected is between 8 MHz and 125 kHz, there is no start-up delay before the new frequency is selected. This is because the old and the new frequencies are derived from the HFINTOSC via the postscaler and multiplexer. 8 MHz 4 MHz (Default after Reset) 2 MHz 1 MHz 500 kHz 250 kHz 125 kHz 31 kHz Note: Following any Reset, the IRCF bits are set to ‘110’ and the frequency selection is set to 4 MHz. The user can modify the IRCF bits to select a different frequency. DS41202C-page 24 Preliminary 2004 Microchip Technology Inc. PIC16F684 3.5 Clock Switching The system clock source can be switched between external and internal clock sources via software using the System Clock Select (SCS) bit. 3.5.1 SYSTEM CLOCK SELECT (SCS) BIT The System Clock Select (SCS) bit (OSCCON<0>) selects the system clock source that is used for the CPU and peripherals. • When SCS = 0, the system clock source is determined by configuration of the FOSC<2:0> bits in the Configuration Word register (CONFIG). • When SCS = 1, the system clock source is chosen by the internal oscillator frequency selected by the IRCF bits. After a Reset, SCS is always cleared. Note: 3.5.2 Any automatic clock switch, which may occur from Two-Speed Start-up or Fail-Safe Clock Monitor, does not update the SCS bit. The user can monitor the OSTS (OSCCON<3>) to determine the current system clock source. OSCILLATOR START-UP TIME-OUT STATUS BIT The Oscillator Start-up Time-out Status (OSTS) bit (OSCCON<3>) indicates whether the system clock is running from the external clock source, as defined by the FOSC bits, or from internal clock source. In particular, OSTS indicates that the Oscillator Start-up Timer (OST) has timed out for LP, XT or HS modes. 3.6 Two-Speed Clock Start-up Mode When the PIC16F684 is configured for LP, XT or HS modes, the Oscillator Start-up Timer (OST) is enabled (see Section 3.3.1 “Oscillator Start-up Timer (OST)”). The OST timer will suspend program execution until 1024 oscillations are counted. Two-Speed Start-up mode minimizes the delay in code execution by operating from the internal oscillator as the OST is counting. When the OST count reaches 1024 and the OSTS bit (OSCCON<3>) is set, program execution switches to the external oscillator. 3.6.1 Two-Speed Start-up mode is configured by the following settings: • IESO = 1 (CONFIG<10>) Internal/External Switch Over bit. • SCS = 0. • FOSC configured for LP, XT or HS mode. Two-Speed Start-up mode is entered after: • Power-on Reset (POR) and, if enabled, after PWRT has expired, or • Wake-up from Sleep. If the external clock oscillator is configured to be anything other than LP, XT or HS mode, then Two-Speed Start-up is disabled. This is because the external clock oscillator does not require any stabilization time after POR or an exit from Sleep. 3.6.2 1. 2. Two-Speed Start-up mode provides additional power savings by minimizing the latency between external oscillator start-up and code execution. In applications that make heavy use of the Sleep mode, Two-Speed Start-up will remove the external oscillator start-up time from the time spent awake and can reduce the overall power consumption of the device. 3. 4. This mode allows the application to wake-up from Sleep, perform a few instructions using the INTOSC as the clock source and go back to Sleep without waiting for the primary oscillator to become stable. 7. Note: TWO-SPEED START-UP MODE CONFIGURATION 5. 6. TWO-SPEED START-UP SEQUENCE Wake-up from Power-on Reset or Sleep. Instructions begin execution by the internal oscillator at the frequency set in the IRCF bits (OSCCON<6:4>). OST enabled to count 1024 clock cycles. OST timed out, wait for falling edge of the internal oscillator. OSTS is set. System clock held low until the next falling edge of new clock (LP, XT or HS mode). System clock is switched to external clock source. Executing a SLEEP instruction will abort the oscillator start-up time and will cause the OSTS bit (OSCCON<3>) to remain clear. 2004 Microchip Technology Inc. Preliminary DS41202C-page 25 PIC16F684 3.6.3 CHECKING EXTERNAL/INTERNAL CLOCK STATUS Checking the state of the OSTS bit (OSCCON<3>) will confirm if the PIC16F684 is running from the external clock source as defined by the FOSC bits in the Configuration Word register (CONFIG) or the internal oscillator. FIGURE 3-7: TWO-SPEED START-UP Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 INTOSC TOST OSC1 0 1 1022 1023 OSC2 Program Counter PC PC + 1 PC + 2 System Clock DS41202C-page 26 Preliminary 2004 Microchip Technology Inc. PIC16F684 3.7 Fail-Safe Clock Monitor The Fail-Safe Clock Monitor (FSCM) is designed to allow the device to continue to operate in the event of an oscillator failure. The FSCM can detect oscillator failure at any point after the device has exited a Reset or Sleep condition and the Oscillator Start-up Timer (OST) has expired. FIGURE 3-8: FSCM BLOCK DIAGRAM Clock Monitor Latch (CM) (edge-triggered) Primary Clock LFINTOSC Oscillator ÷ 64 31 kHz (~32 µs) 488 Hz (~2 ms) S Q C Q The frequency of the internal oscillator will depend upon the value contained in the IRCF bits (OSCCON<6:4>). Upon entering the Fail-Safe condition, the OSTS bit (OSCCON<3>) is automatically cleared to reflect that the internal oscillator is active and the WDT is cleared. The SCS bit (OSCCON<0>) is not updated. Enabling FSCM does not affect the LTS bit. The FSCM sample clock is generated by dividing the INTRC clock by 64. This will allow enough time between FSCM sample clocks for a system clock edge to occur. Figure 3-8 shows the FSCM block diagram. On the rising edge of the sample clock, the monitoring latch (CM = 0) will be cleared. On a falling edge of the primary system clock, the monitoring latch will be set (CM = 1). In the event that a falling edge of the sample clock occurs, and the monitoring latch is not set, a clock failure has been detected. The assigned internal oscillator is enabled when FSCM is enabled, as reflected by the IRCF. Note: Two-Speed Start-up is automatically enabled when the Fail-Safe Clock Monitor mode is enabled. Note: Primary clocks with a frequency ≤ ~488 Hz will be considered failed by the FSCM. A slow starting oscillator can cause an FSCM interrupt. Clock Failure Detected The FSCM function is enabled by setting the FCMEN bit in the Configuration Word register (CONFIG). It is applicable to all external clock options (LP, XT, HS, EC, RC or IO modes). In the event of an external clock failure, the FSCM will set the OSFIF bit (PIR1<2>) and generate an oscillator fail interrupt if the OSFIE bit (PIE1<2>) is set. The device will then switch the system clock to the internal oscillator. The system clock will continue to come from the internal oscillator unless the external clock recovers and the Fail-Safe condition is exited. 3.7.1 FAIL-SAFE CONDITION CLEARING The Fail-Safe condition is cleared after a Reset, the execution of a SLEEP instruction, or a modification of the SCS bit. While in Fail-Safe condition, the PIC16F684 uses the internal oscillator as the system clock source. The IRCF bits (OSCCON<6:4>) can be modified to adjust the internal oscillator frequency without exiting the Fail-Safe condition. The Fail-Safe condition must be cleared before the OSFIF flag can be cleared. 2004 Microchip Technology Inc. Preliminary DS41202C-page 27 PIC16F684 FIGURE 3-9: FSCM TIMING DIAGRAM Sample Clock Oscillator Failure System Clock Output CM Output (Q) Failure Detected OSCFIF CM Test Note: 3.7.2 CM Test CM Test The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in this example have been chosen for clarity. RESET OR WAKE-UP FROM SLEEP The FSCM is designed to detect oscillator failure at any point after the device has exited a Reset or Sleep condition and the Oscillator Start-up Timer (OST) has expired. If the external clock is EC or RC mode, monitoring will begin immediately following these events. For LP, XT or HS mode, the external oscillator may require a start-up time considerably longer than the FSCM sample clock time, a false clock failure may be detected (see Figure 3-9). To prevent this, the internal oscillator is automatically configured as the system clock and functions until the external clock is stable (the OST has timed out). This is identical to Two-Speed Start-up mode. Once the external oscillator is stable, the LFINTOSC returns to its role as the FSCM source. Note: Due to the wide range of oscillator start-up times, the Fail-Safe circuit is not active during oscillator start-up (i.e., after exiting Reset or Sleep). After an appropriate amount of time, the user should check the OSTS bit (OSCCON<3>) to verify the oscillator start-up and system clock switchover has successfully completed. DS41202C-page 28 Preliminary 2004 Microchip Technology Inc. PIC16F684 REGISTER 3-2: OSCCON – OSCILLATOR CONTROL REGISTER (ADDRESS: 8Fh) U-0 R/W-1 — IRCF2 R/W-1 IRCF1 R/W-0 R-1 IRCF0 OSTS (1) R-0 R-0 R/W-0 HTS LTS SCS bit 7 bit 0 bit 7 Unimplemented: Read as ‘0’ bit 6-4 IRCF<2:0>: Internal Oscillator Frequency Select bits 000 = 31 kHz 001 = 125 kHz 010 = 250 kHz 011 = 500 kHz 100 = 1 MHz 101 = 2 MHz 110 = 4 MHz 111 = 8 MHz bit 3 OSTS: Oscillator Start-up Time-out Status bit 1 = Device is running from the external system clock defined by FOSC<2:0> 0 = Device is running from the internal system clock (HFINTOSC or LFINTOSC) bit 2 HTS: HFINTOSC (High Frequency – 8 MHz to 125 kHz) Status bit 1 = HFINTOSC is stable 0 = HFINTOSC is not stable bit 1 LTS: LFINTOSC (Low Frequency – 31 kHz) Stable bit 1 = LFINTOSC is stable 0 = LFINTOSC is not stable bit 0 SCS: System Clock Select bit 1 = Internal oscillator is used for system clock 0 = Clock source defined by FOSC<2:0> Note 1: Bit resets to ‘0’ with Two-Speed Start-up and LP, XT or HS selected as the Oscillator mode or Fail-Safe mode is enabled. Legend: TABLE 3-2: Address R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown SUMMARY OF REGISTERS ASSOCIATED WITH CLOCK SOURCES Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on: POR, BOD Value on all other Resets 0Ch PIR1 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF TMR1IF 0000 0000 0000 0000 8Ch PIE1 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE TMR1IE 0000 0000 0000 0000 8Fh OSCCON — IRCF2 IRCF1 IRCF0 OSTS HTS LTS SCS -110 x000 -110 x000 90h OSCTUNE — — — TUN4 TUN3 TUN2 TUN1 TUN0 ---0 0000 ---u uuuu 2007h(1) CONFIG CPD CP WDTE FOSC2 FOSC1 FOSC0 Legend: Note 1: MCLRE PWRTE — — x = unknown, u = unchanged, — = unimplemented locations read as ‘0’. Shaded cells are not used by oscillators. See Register 12-1 for operation of all Configuration Word register bits. 2004 Microchip Technology Inc. Preliminary DS41202C-page 29 PIC16F684 NOTES: DS41202C-page 30 Preliminary 2004 Microchip Technology Inc. PIC16F684 4.0 I/O PORTS EXAMPLE 4-1: There are as many as twelve general purpose I/O pins available. Depending on which peripherals are enabled, some or all of the pins may not be available as general purpose I/O. In general, when a peripheral is enabled, the associated pin may not be used as a general purpose I/O pin. Note: 4.1 Additional information on I/O ports may be found in the “PICmicro® Mid-Range MCU Family Reference Manual” (DS33023). STATUS,RP0 PORTA 07h CMCON0 STATUS,RP0 ANSEL 0Ch TRISA BCF STATUS,RP0 4.2 PORTA and the TRISA Registers PORTA is a 6-bit wide, bidirectional port. The corresponding data direction register is TRISA (Register 4-2). Setting a TRISA bit (= 1) will make the corresponding PORTA pin an input (i.e., put the corresponding output driver in a High-impedance mode). Clearing a TRISA bit (= 0) will make the corresponding PORTA pin an output (i.e., put the contents of the output latch on the selected pin). The exception is RA3, which is input only and its TRIS bit will always read as ‘1’. Example 4-1 shows how to initialize PORTA. Reading the PORTA register (Register 4-1) reads the status of the pins, whereas writing to it will write to the port latch. All write operations are read-modify-write operations. Therefore, a write to a port implies that the port pins are read, this value is modified and then written to the port data latch. RA3 reads ‘0’ when MCLRE = 1. INITIALIZING PORTA BCF CLRF MOVLW MOVWF BSF CLRF MOVLW MOVWF ;Bank 0 ;Init PORTA ;Set RA<2:0> to ;digital I/O ;Bank 1 ;digital I/O ;Set RA<3:2> as inputs ;and set RA<5:4,1:0> ;as outputs ;Bank 0 Additional Pin Functions Every PORTA pin on the PIC16F684 has an interrupton-change option and a weak pull-up option. RA0 has an Ultra Low-Power Wake-up option. The next three sections describe these functions. 4.2.1 WEAK PULL-UPS Each of the PORTA pins, except RA3, has an individually configurable internal weak pull-up. Control bits WPUAx enable or disable each pull-up. Refer to Register 4-3. Each weak pull-up is automatically turned off when the port pin is configured as an output. The pull-ups are disabled on a Power-on Reset by the RAPU bit (OPTION_REG<7>). A weak pull-up is automatically enabled for RA3 when configured as MCLR and disabled when RA3 is an I/O. There is no software control of the MCLR pull-up. The TRISA register controls the direction of the PORTA pins, even when they are being used as analog inputs. The user must ensure the bits in the TRISA register are maintained set when using them as analog inputs. I/O pins configured as analog input always read ‘0’. Note: The ANSEL (91h) and CMCON0 (19h) registers must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read ‘0’. REGISTER 4-1: PORTA – PORTA REGISTER (ADDRESS: 05h) U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-0 R/W-0 — — RA5 RA4 RA3 RA2 RA1 RA0 bit 7 bit 0 bit 7-6: Unimplemented: Read as ‘0’ bit 5-0: RA<5:0>: PORTA I/O Pin bit 1 = Port pin is > VIH 0 = Port pin is < VIL Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 31 PIC16F684 REGISTER 4-2: TRISA – PORTA TRI-STATE REGISTER (ADDRESS: 85h) U-0 U-0 R/W-1 R/W-1 R-1 R/W-1 R/W-1 R/W-1 — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 bit 7 bit 0 bit 7-6: Unimplemented: Read as ‘0’ bit 5-0: TRISA<5:0>: PORTA Tri-State Control bit 1 = PORTA pin configured as an input (tri-stated) 0 = PORTA pin configured as an output Note 1: TRISA<3> always reads ‘1’. 2: TRISA<5:4> always reads ‘1’ in XT, HS and LP OSC modes. Legend: REGISTER 4-3: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown WPUA – WEAK PULL-UP REGISTER (ADDRESS: 95h) U-0 U-0 R/W-1 R/W-1 U-0 R/W-1 R/W-1 R/W-1 — — WPUA5 WPUA4 — WPUA2 WPUA1 WPUA0 bit 7 bit 0 bit 7-6 Unimplemented: Read as ‘0’ bit 5-4 WPUA<5:4>: Weak Pull-up Register bit 1 = Pull-up enabled 0 = Pull-up disabled bit 3 Unimplemented: Read as ‘0’ bit 2-0 WPUA<2:0>: Weak Pull-up Register bit 1 = Pull-up enabled 0 = Pull-up disabled Note 1: Global RAPU must be enabled for individual pull-ups to be enabled. 2: The weak pull-up device is automatically disabled if the pin is in Output mode (TRISA = 0). 3: The RA3 pull-up is enabled when configured as MCLR and disabled as an I/O in the configuration word. 4: WPUA<5:4> always reads ‘1’ in XT, HS and LP OSC modes. Legend: DS41202C-page 32 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 4.2.2 INTERRUPT-ON-CHANGE Each of the PORTA pins is individually configurable as an interrupt-on-change pin. Control bits IOCAx enable or disable the interrupt function for each pin. Refer to Register 4-4. The interrupt-on-change is disabled on a Power-on Reset. For enabled interrupt-on-change pins, the values are compared with the old value latched on the last read of PORTA. The ‘mismatch’ outputs of the last read are OR’d together to set the PORTA Change Interrupt Flag bit (RAIF) in the INTCON register (Register 2-3). This interrupt can wake the device from Sleep. The user, in the Interrupt Service Routine, clears the interrupt by: a) Any read or write of PORTA. This will end the mismatch condition, then, Clear the flag bit RAIF. b) A mismatch condition will continue to set flag bit RAIF. Reading PORTA will end the mismatch condition and allow flag bit RAIF to be cleared. The latch holding the last read value is not affected by a MCLR nor BOD Reset. After these resets, the RAIF flag will continue to be set if a mismatch is present. Note: REGISTER 4-4: If a change on the I/O pin should occur when the read operation is being executed (start of the Q2 cycle), then the RAIF interrupt flag may not get set. IOCA – INTERRUPT-ON-CHANGE PORTA REGISTER (ADDRESS: 96h) U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 — — IOCA5 IOCA4 IOCA3 IOCA2 IOCA1 IOCA0 bit 7 bit 0 bit 7-6 Unimplemented: Read as ‘0’ bit 5-0 IOCA<5:0>: Interrupt-on-change PORTA Control bit 1 = Interrupt-on-change enabled 0 = Interrupt-on-change disabled Note 1: Global Interrupt Enable (GIE) must be enabled for individual interrupts to be recognized. 2: IOCA<5:4> always reads ‘1’ in XT, HS and LP OSC modes. Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 33 PIC16F684 4.2.3 ULTRA LOW-POWER WAKE-UP The Ultra Low-power Wake-up (ULPWU) on RA0 allows a slow falling voltage to generate an interrupton-change on RA0 without excess current consumption. The mode is selected by setting the ULPWUE bit (PCON<5>). This enables a small current sink which can be used to discharge a capacitor on RA0. To use this feature, the RA0 pin is configured to output ‘1’ to charge the capacitor, interrupt-on-change for RA0 is enabled, and RA0 is configured as an input. The ULPWUE bit is set to begin the discharge and a SLEEP instruction is performed. When the voltage on RA0 drops below VIL, an interrupt will be generated which will cause the device to wake-up. Depending on the state of the GIE bit (INTCON<7>), the device will either jump to the interrupt vector (0004h) or execute the next instruction when the interrupt event occurs. See Section 4.2.2 “Interrupt-on-change” and Section 12.4.3 “PORTA Interrupt” for more information. This feature provides a low-power technique for periodically waking up the device from Sleep. The time-out is dependent on the discharge time of the RC circuit on RA0. See Example 4-2 for initializing the Ultra Low-Power Wake-up module. DS41202C-page 34 The series resistor provides overcurrent protection for the RA0 pin and can allow for software calibration of the time-out (see Figure 4-1). A timer can be used to measure the charge time and discharge time of the capacitor. The charge time can then be adjusted to provide the desired interrupt delay. This technique will compensate for the affects of temperature, voltage and component accuracy. The Ultra Low-power Wake-up peripheral can also be configured as a simple Programmable Low Voltage Detect or temperature sensor. Note: For more information, refer to AN879, “Using the Microchip Ultra Low-Power Wake-up Module” Application Note (DS00879). EXAMPLE 4-2: BCF BSF MOVLW MOVWF BSF BCF BCF CALL BSF BSF BSF MOVLW MOVWF SLEEP Preliminary ULTRA LOW-POWER WAKE-UP INITIALIZATION STATUS,RP0 PORTA,0 H’7’ CMCON0 STATUS,RP0 ANSEL,0 TRISA,0 CapDelay PCON,ULPWUE IOCA,0 TRISA,0 B’10001000’ INTCON ;Bank 0 ;Set RA0 data latch ;Turn off ;comparators ;Bank 1 ;RA0 to digital I/O ;Output high to ; charge capacitor ;Enable ULP Wake-up ;Select RA0 IOC ;RA0 to input ;Enable interrupt ; and clear flag ;Wait for IOC 2004 Microchip Technology Inc. PIC16F684 FIGURE 4-1: BLOCK DIAGRAM OF RAO Analog(1) Input Mode VDD Data Bus D Q Weak CK Q WR WPUDA RAPU RD WPUDA VDD D WR PORTA Q I/O PIN CK Q VSS + D WR TRISA VT Q CK Q IULP 0 RD TRISA 1 Analog(1) Input Mode VSS ULPWUE RD PORTA D WR IOCA Q Q CK Q D EN RD IOCA Q Q3 D EN Interrupt-onChange RD PORTA To Comparator To A/D Converter Note 1: Comparator mode and ANSEL determines Analog Input mode. 2004 Microchip Technology Inc. Preliminary DS41202C-page 35 PIC16F684 4.2.4 PIN DESCRIPTIONS AND DIAGRAMS FIGURE 4-2: Each PORTA pin is multiplexed with other functions. The pins and their combined functions are briefly described here. For specific information about individual functions such as the comparator or the A/D, refer to the appropriate section in this data sheet. 4.2.4.1 RA0/AN0/C1IN+/ICSPDAT/ULPWU Data Bus D WR WPUA a general purpose I/O an analog input for the A/D an analog input to the comparator In-Circuit Serial Programming data an analog input for the Ultra Low-power Wake-up 4.2.4.2 VDD Weak RAPU RD WPUA D WR PORTA VDD Q CK Q I/O PIN D WR TRISA Q CK Q VSS Analog(1) Input Mode RA1/AN1/C1IN-/VREF/ICSPCLK Figure 4-2 shows the diagram for this pin. The RA1 pin is configurable to function as one of the following: • • • • • Q Analog(1) Input Mode CK Q Figure 4-2 shows the diagram for this pin. The RA0 pin is configurable to function as one of the following: • • • • • BLOCK DIAGRAM OF RA1 a general purpose I/O an analog input for the A/D an analog input to the comparator a voltage reference input for the A/D In-Circuit Serial Programming clock RD TRISA RD PORTA D Q Q CK Q WR IOCA D EN RD IOCA Q Q3 D EN Interrupt-onChange RD PORTA To Comparator To A/D Converter Note DS41202C-page 36 Preliminary 1: Comparator mode and ANSEL determines Analog Input mode. 2004 Microchip Technology Inc. PIC16F684 4.2.4.3 4.2.4.4 RA2/AN2/T0CKI/INT/C1OUT RA3/MCLR/VPP Figure 4-3 shows the diagram for this pin. The RA2 pin is configurable to function as one of the following: Figure 4-4 shows the diagram for this pin. The RA3 pin is configurable to function as one of the following: • • • • • • a general purpose input • as Master Clear Reset with weak pull-up a general purpose I/O an analog input for the A/D the clock input for TMR0 an external edge triggered interrupt a digital output from comparator 1 FIGURE 4-3: Data Bus D WR WPUA VDD Analog(1) Input Mode MCLRE Data Bus Q RD TRISA Weak MCLRE D COUT 1 Enable WR PORTA Q CK Q WR TRISA COUT 1 I/O PIN Interrupt-onChange Q VSS VSS Q D Q Q Q3 D EN RD PORTA Analog(1) Input Mode RD TRISA Input pin Q EN Q CK CK RD IOCA 0 D WR IOCA VDD MCLRE VSS RD PORTA RAPU Weak Reset VDD RD WPUA D BLOCK DIAGRAM OF RA3 BLOCK DIAGRAM OF RA2 Q CK FIGURE 4-4: RD PORTA Q D CK WR IOCA Q D Q EN RD IOCA Q Q3 D EN Interrupt-onChange RD PORTA To TMR0 To INT To A/D Converter Note 1: Analog Input mode is generated by ANSEL. 2004 Microchip Technology Inc. Preliminary DS41202C-page 37 PIC16F684 4.2.4.5 4.2.4.6 RA4/AN3/T1G/OSC2/CLKOUT RA5/T1CKI/OSC1/CLKIN Figure 4-5 shows the diagram for this pin. The RA4 pin is configurable to function as one of the following: Figure 4-6 shows the diagram for this pin. The RA5 pin is configurable to function as one of the following: • • • • • • • • • a general purpose I/O an analog input for the A/D a TMR1 gate input a crystal/resonator connection a clock output a general purpose I/O a TMR1 clock input a crystal/resonator connection a clock input FIGURE 4-6: FIGURE 4-5: Analog(3) Input Mode Data Bus WR WPUA D CK BLOCK DIAGRAM OF RA5 BLOCK DIAGRAM OF RA4 INTOSC Mode CLK(1) Modes Q Data Bus VDD Q WR WPUA Weak CK Weak Q RAPU Oscillator Circuit Oscillator Circuit OSC1 D WR PORTA CK Q FOSC/4 OSC2 VDD CLKOUT Enable D WR PORTA 1 0 CLKOUT Enable D WR TRISA CK Q Q WR IOCA VSS Q CK Q D Q EN Q EN Q Q3 RD IOCA D Q Interrupt-onChange Q INTOSC Mode D Q RD IOCA CK (2) RD PORTA CK Q RD PORTA Analog Input Mode D Q RD TRISA CLKOUT Enable RD TRISA CK D WR TRISA INTOSC/ RC/EC(2) VDD Q I/O PIN I/O PIN Q VSS WR IOCA VDD Q RD WPUA RAPU RD WPUA D TMR1LPEN(1) Q3 Q D EN D Interrupt-onChange EN RD PORTA RD PORTA To TMR1 or CLKGEN To T1G To A/D Converter Note Note 1: CLK modes are XT, HS, LP, LPTMR1 and CLKOUT Enable. 1: Timer1 LP Oscillator enabled. 2: When using Timer1 with LP oscillator, the Schmitt Trigger is bypassed. 2: With CLKOUT option. 3: Analog Input mode comes from ANSEL. DS41202C-page 38 Preliminary 2004 Microchip Technology Inc. PIC16F684 TABLE 4-1: Addr 05h SUMMARY OF REGISTERS ASSOCIATED WITH PORTA Name PORTA 0Bh/8Bh INTCON Bit 7 Bit 6 Bit 5 Bit 4 Bit 2 Bit 1 Bit 0 Value on: POR, BOD Value on all other Resets — — RA5 RA4 RA3 RA2 RA1 RA0 --xx xx00 --uu uu00 GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 0000 0000 C2INV C1INV CIS CM2 CM1 CM0 0000 0000 0000 0000 T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111 19h CMCON0 C2OUT C1OUT 81h OPTION_REG RAPU INTEDG 85h TRISA — — 91h ANSEL ANS7 ANS6 95h WPUA — — WPUA5 WPUA4 96h IOCA — — IOCA5 Legend: Bit 3 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111 --11 1111 ANS5 ANS4 IOCA4 ANS3 — IOCA3 ANS2 ANS1 ANS0 1111 1111 1111 1111 WPUA2 WPUA1 WPUA0 --11 -111 --11 -111 IOCA2 IOCA1 IOCA0 --00 0000 --00 0000 x = unknown, u = unchanged, — = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA. 2004 Microchip Technology Inc. Preliminary DS41202C-page 39 PIC16F684 4.3 FIGURE 4-7: PORTC PORTC is a general purpose I/O port consisting of 6 bidirectional pins. The pins can be configured for either digital I/O or analog input to A/D converter or comparator. For specific information about individual functions such as the Enhanced CCP or the A/D, refer to the appropriate section in this data sheet. Note: The ANSEL (91h) and CMCON0 (19h) registers must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read ‘0’. EXAMPLE 4-3: BCF CLRF MOVLW MOVWF BSF CLRF MOVLW MOVWF BCF 4.3.1 STATUS,RP0 PORTC 07h CMCON0 STATUS,RP0 ANSEL 0Ch TRISC STATUS,RP0 INITIALIZING PORTC ;Bank 0 ;Init PORTC ;Set RC<4,1:0> to ;digital I/O ;Bank 1 ;digital I/O ;Set RC<3:2> as inputs ;and set RC<5:4,1:0> ;as outputs ;Bank 0 BLOCK DIAGRAM OF RC0 AND RC1 Data Bus D WR PORTC CK VDD Q Q I/O PIN D WR TRISC CK Q Q VSS Analog Input Mode(1) RD TRISC RD PORTC To Comparators To A/D Converter Note 1: Analog Input mode comes from ANSEL or Comparator mode. RC0/AN4/C2IN+ The RC0 is configurable to function as one of the following: • a general purpose I/O • an analog input for the A/D Converter • an analog input to the comparator 4.3.2 RC1/AN5/C2IN- The RC1 is configurable to function as one of the following: • a general purpose I/O • an analog input for the A/D Converter • an analog input to the comparator DS41202C-page 40 Preliminary 2004 Microchip Technology Inc. PIC16F684 4.3.3 RC2/AN6/P1D 4.3.5 RC4/C2OUT/P1B The RC2 is configurable to function as one of the following: The RC4 is configurable to function as one of the following: • a general purpose I/O • an analog input for the A/D Converter • a digital output from the Enhanced CCP • a general purpose I/O • a digital output from the comparator • a digital output from the Enhanced CCP 4.3.4 Note: RC3/AN7/P1C Enabling both C2OUT and P1B will cause a conflict on RC4 and create unpredictable results. Therefore, if C2OUT is enabled, the ECCP can not be used in Half-bridge or Full-bridge mode and vise-versa. The RC3 is configurable to function as one of the following: • a general purpose I/O • an analog input for the A/D Converter • a digital output from the Enhanced CCP FIGURE 4-8: FIGURE 4-9: C2OUT EN CCPOUT EN BLOCK DIAGRAM OF RC2 AND RC3 D WR PORTC CK Q WR TRISC CK D CCPOUT I/O PIN Q 1 I/O PIN WR PORTC CK Q VSS Q D Q VSS Analog Input Mode(1) RD TRISC WR TRISC Q CK Q RD TRISC RD PORTC To A/D Converter Note 0 Data Bus 0 D 1 CCPOUT EN CCPOUT VDD Q VDD C2OUT EN C2OUT Data Bus CCPOUT Enable BLOCK DIAGRAM OF RC4 1: RD PORTC Analog Input mode comes from ANSEL. 2004 Microchip Technology Inc. Note Preliminary 1: Port/Peripheral Select signals selects between port data and peripheral output. DS41202C-page 41 PIC16F684 4.3.6 RC5/CCP1/P1A The RC5 is configurable to function as one of the following: • a general purpose I/O • a digital input/output for the Enhanced CCP FIGURE 4-10: BLOCK DIAGRAM OF RC5 PIN Data bus D WR PORTC CK CCP1OUT Enable Q Q VDD CCP1OUT 1 0 D WR TRISC CK I/O PIN Q Q VSS RD TRISC RD PORTC To Enhanced CCP DS41202C-page 42 Preliminary 2004 Microchip Technology Inc. PIC16F684 REGISTER 4-5: PORTC – PORTC REGISTER (ADDRESS: 07h) U-0 U-0 R/W-x R/W-x R/W-x R/W-x R/W-0 R/W-0 — — RC5 RC4 RC3 RC2 RC1 RC0 bit 7 bit 0 bit 7-6: Unimplemented: Read as ‘0’ bit 5-0: RC<5:0>: PORTC General Purpose I/O Pin bits 1 = Port pin is >VIH 0 = Port pin is <VIL Legend: REGISTER 4-6: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown TRISC – PORTC TRI-STATE REGISTER (ADDRESS: 87h) U-0 U-0 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 bit 7 bit 0 bit 7-6: Unimplemented: Read as ‘0’ bit 5-0: TRISC<5:0>: PORTC Tri-State Control bit 1 = PORTC pin configured as an input (tri-stated) 0 = PORTC pin configured as an output Legend: TABLE 4-2: Address R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared SUMMARY OF REGISTERS ASSOCIATED WITH PORTC Name Bit 7 Bit 6 — — 07h PORTC 19h CMCON0 87h TRISC — — 91h ANSEL ANS7 ANS6 Legend: x = Bit is unknown C2OUT C1OUT Bit 5 Bit 4 Bit 3 Bit 2 RC5 RC4 RC3 RC2 C2INV C1INV CIS CM2 Value on all other Resets Bit 0 Value on: POR, BOD RC1 RC0 --xx xx00 --uu uu00 CM1 CM0 0000 0000 0000 0000 Bit 1 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 --11 1111 --11 1111 ANS5 ANS4 ANS3 ANS2 ANS1 ANS0 1111 1111 1111 1111 x = unknown, u = unchanged, — = unimplemented locations read as ‘0’. Shaded cells are not used by PORTC. 2004 Microchip Technology Inc. Preliminary DS41202C-page 43 PIC16F684 NOTES: DS41202C-page 44 Preliminary 2004 Microchip Technology Inc. PIC16F684 5.0 TIMER0 MODULE Counter mode is selected by setting the T0CS bit (OPTION_REG<5>). In this mode, the Timer0 module will increment either on every rising or falling edge of pin RA2/T0CKI. The incrementing edge is determined by the source edge (T0SE) control bit (OPTION_REG<4>). Clearing the T0SE bit selects the rising edge. The Timer0 module timer/counter has the following features: • • • • • • 8-bit timer/counter Readable and writable 8-bit software programmable prescaler Internal or external clock select Interrupt on overflow from FFh to 00h Edge select for external clock Note: Figure 5-1 is a block diagram of the Timer0 module and the prescaler shared with the WDT. Note: 5.1 5.2 Additional information on the Timer0 module is available in the “PICmicro® Mid-Range MCU Family Reference Manual” (DS33023). Timer0 Interrupt A Timer0 interrupt is generated when the TMR0 register timer/counter overflows from FFh to 00h. This overflow sets the T0IF bit (INTCON<2>). The interrupt can be masked by clearing the T0IE bit (INTCON<5>). The T0IF bit must be cleared in software by the Timer0 module Interrupt Service Routine before re-enabling this interrupt. The Timer0 interrupt cannot wake the processor from Sleep since the timer is shut off during Sleep. Timer0 Operation Timer mode is selected by clearing the T0CS bit (OPTION_REG<5>). In Timer mode, the Timer0 module will increment every instruction cycle (without prescaler). If TMR0 is written, the increment is inhibited for the following two instruction cycles. The user can work around this by writing an adjusted value to the TMR0 register. FIGURE 5-1: Counter mode has specific external clock requirements. Additional information on these requirements is available in the ”PICmicro® Mid-Range MCU Family Reference Manual” (DS33023). BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER CLKOUT (= FOSC/4) Data Bus 0 8 1 SYNC 2 Cycles 1 T0CKI pin TMR0 0 0 T0CS T0SE Set Flag bit T0IF on Overflow 8-bit Prescaler PSA 1 8 PSA WDTE SWDTEN PS<2:0> 16-bit Prescaler 31 kHz INTRC 1 WDT Time-out 0 16 Watchdog Timer PSA WDTPS<3:0> Note 1: T0SE, T0CS, PSA, PS<2:0> are bits in the Option register, WDTPS<3:0> are bits in the WDTCON register. 2004 Microchip Technology Inc. Preliminary DS41202C-page 45 PIC16F684 5.3 Using Timer0 with an External Clock When no prescaler is used, the external clock input is the same as the prescaler output. The synchronization of T0CKI, with the internal phase clocks, is accomplished by sampling the prescaler output on the Q2 and Q4 cycles of the internal phase clocks. Therefore, it is necessary for T0CKI to be high for at least 2 TOSC (and a small RC delay of 20 ns) and low for at least 2 TOSC (and a small RC delay of 20 ns). Refer to the electrical specification of the desired device. Note: The ANSEL (91h) and CMCON0 (19h) registers must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read ‘0’. REGISTER 5-1: OPTION_REG – OPTION REGISTER (ADDRESS: 81h) R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 RAPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 bit 7 bit 0 bit 7 RAPU: PORTA Pull-up Enable bit 1 = PORTA pull-ups are disabled 0 = PORTA pull-ups are enabled by individual port latch values in WPUA register bit 6 INTEDG: Interrupt Edge Select bit 1 = Interrupt on rising edge of RA2/INT pin 0 = Interrupt on falling edge of RA2/INT pin bit 5 T0CS: TMR0 Clock Source Select bit 1 = Transition on RA2/T0CKI pin 0 = Internal instruction cycle clock (CLKOUT) bit 4 T0SE: TMR0 Source Edge Select bit 1 = Increment on high-to-low transition on RA2/T0CKI pin 0 = Increment on low-to-high transition on RA2/T0CKI pin bit 3 PSA: Prescaler Assignment bit 1 = Prescaler is assigned to the WDT 0 = Prescaler is assigned to the Timer0 module bit 2-0 PS<2:0>: Prescaler Rate Select bits Bit Value 000 001 010 011 100 101 110 111 TMR0 Rate WDT Rate(1) 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256 1:1 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128 Note 1: A dedicated 16-bit WDT postscaler is available for the PIC16F684. See Section 12.6 “Watchdog Timer (WDT)” for more information. Legend: DS41202C-page 46 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 5.4 EXAMPLE 5-1: Prescaler An 8-bit counter is available as a prescaler for the Timer0 module, or as a postscaler for the Watchdog Timer. For simplicity, this counter will be referred to as “prescaler” throughout this data sheet. The prescaler assignment is controlled in software by the control bit PSA (OPTION_REG<3>). Clearing the PSA bit will assign the prescaler to Timer0. Prescale values are selectable via the PS<2:0> bits (OPTION_REG<2:0>). The prescaler is not readable or writable. When assigned to the Timer0 module, all instructions writing to the TMR0 register (e.g., CLRF 1, MOVWF 1, BSF 1, x....etc.) will clear the prescaler. When assigned to WDT, a CLRWDT instruction will clear the prescaler along with the Watchdog Timer. 5.4.1 SWITCHING PRESCALER ASSIGNMENT The prescaler assignment is fully under software control (i.e., it can be changed “on the fly” during program execution). To avoid an unintended device Reset, the following instruction sequence (Example 5-1 and Example 5-2) must be executed when changing the prescaler assignment from Timer0 to WDT. TABLE 5-1: Address 01h BCF STATUS,RP0 CLRWDT CLRF TMR0 BSF ;Bank 0 ;Clear WDT ;Clear TMR0 and ; prescaler ;Bank 1 STATUS,RP0 MOVLW b’00101111’ MOVWF OPTION_REG CLRWDT MOVLW MOVWF BCF b’00101xxx’ OPTION_REG STATUS,RP0 ;Required if desired ; PS2:PS0 is ; 000 or 001 ; ;Set postscaler to ; desired WDT rate ;Bank 0 To change prescaler from the WDT to the TMR0 module, use the sequence shown in Example 5-2. This precaution must be taken even if the WDT is disabled. EXAMPLE 5-2: CHANGING PRESCALER (WDT→TIMER0) CLRWDT BSF STATUS,RP0 MOVLW b’xxxx0xxx’ MOVWF BCF OPTION_REG STATUS,RP0 ;Clear WDT and ; prescaler ;Bank 1 ;Select TMR0, ; prescale, and ; clock source ; ;Bank 0 REGISTERS ASSOCIATED WITH TIMER0 Name TMR0 0Bh/8Bh INTCON 81h OPTION_REG 85h TRISA Legend: CHANGING PRESCALER (TIMER0→WDT) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Timer0 Module register Value on POR, BOD Value on all other Resets xxxx xxxx uuuu uuuu GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 0000 0000 RAPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111 — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111 --11 1111 — = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown. Shaded cells are not used by the Timer0 module. 2004 Microchip Technology Inc. Preliminary DS41202C-page 47 PIC16F684 NOTES: DS41202C-page 48 Preliminary 2004 Microchip Technology Inc. PIC16F684 6.0 TIMER1 MODULE WITH GATE CONTROL The Timer1 Control register (T1CON), shown in Register 6-1, is used to enable/disable Timer1 and select the various features of the Timer1 module. The PIC16F684 has a 16-bit timer. Figure 6-1 shows the basic block diagram of the Timer1 module. Timer1 has the following features: Note: • • • • • • • 16-bit timer/counter (TMR1H:TMR1L) Readable and writable Internal or external clock selection Synchronous or asynchronous operation Interrupt on overflow from FFFFh to 0000h Wake-up upon overflow (Asynchronous mode) Optional external enable input - Selectable gate source: T1G or C2 output (T1GSS) - Selectable gate polarity (T1GINV) • Optional LP oscillator FIGURE 6-1: Additional information on timer modules is available in the “PICmicro® Mid-Range MCU Family Reference Manual” (DS33023). TIMER1 ON THE PIC16F684 BLOCK DIAGRAM TMR1ON TMR1GE TMR1ON TMR1GE Set Flag bit TMR1IF on Overflow To C2 Comparator Module TMR1 Clock TMR1(1) TMR1H 1 (2) OSC1/T1CKI OSC2/T1G INTOSC without CLKOUT T1OSCEN Synchronized Clock Input 0 TMR1L OSCILLATOR T1SYNC 1 FOSC/4 Internal Clock Prescaler 1, 2, 4, 8 2: Synchronize det 0 2 T1CKPS<1:0> Sleep Input TMR1CS 1 C2OUT Note 1: T1GINV 0 Timer1 increments on the rising edge. ST Buffer is low power type when using LP oscillator or high speed type when using T1CKI. 2004 Microchip Technology Inc. Preliminary T1GSS DS41202C-page 49 PIC16F684 6.1 Timer1 Modes of Operation 6.3 Timer1 can operate in one of three modes: • 16-bit Timer with prescaler • 16-bit Synchronous counter • 16-bit Asynchronous counter In Timer mode, Timer1 is incremented on every instruction cycle. In Counter mode, Timer1 is incremented on the rising edge of the external clock input T1CKI. In addition, the Counter mode clock can be synchronized to the microcontroller system clock or run asynchronously. In Counter and Timer modules, the counter/timer clock can be gated by the Timer1 gate, which can be selected as either the T1G pin or Comparator 2 output. If an external clock oscillator is needed (and the microcontroller is using the INTOSC without CLKOUT), Timer1 can use the LP oscillator as a clock source. Note: 6.2 In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge. Timer1 has four prescaler options allowing 1, 2, 4 or 8 divisions of the clock input. The T1CKPS bits (T1CON<5:4>) control the prescale counter. The prescale counter is not directly readable or writable; however, the prescaler counter is cleared upon a write to TMR1H or TMR1L. 6.4 Timer1 Gate Timer1 gate source is software configurable to be the T1G pin or the output of Comparator 2. This allows the device to directly time external events using T1G or analog events using Comparator 2. See CMCON1 (Register 8-2) for selecting the Timer1 gate source. This feature can simplify the software for a Delta-Sigma A/D converter and many other applications. For more information on Delta-Sigma A/D converters, see the Microchip web site (www.microchip.com). Note: Timer1 Interrupt The Timer1 register pair (TMR1H:TMR1L) increments to FFFFh and rolls over to 0000h. When Timer1 rolls over, the Timer1 interrupt flag bit (PIR1<0>) is set. To enable the interrupt on rollover, you must set these bits: Timer1 Prescaler TMR1GE bit (T1CON<6>) must be set to use either T1G or C2OUT as the Timer1 gate source. See Register 8-2 for more information on selecting the Timer1 gate source. Timer1 gate can be inverted using the T1GINV bit (T1CON<7>), whether it originates from the T1G pin or Comparator 2 output. This configures Timer1 to measure either the active-high or active-low time between events. • Timer1 interrupt enable bit (PIE1<0>) • PEIE bit (INTCON<6>) • GIE bit (INTCON<7>) The interrupt is cleared by clearing the TMR1IF bit in the Interrupt Service Routine. Note: The TMR1H:TTMR1L register pair and the TMR1IF bit should be cleared before enabling interrupts. FIGURE 6-2: TIMER1 INCREMENTING EDGE T1CKI = 1 when TMR1 Enabled T1CKI = 0 when TMR1 Enabled Note 1: 2: Arrows indicate counter increments. In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of the clock. DS41202C-page 50 Preliminary 2004 Microchip Technology Inc. PIC16F684 REGISTER 6-1: T1CON – TIMER1 CONTROL REGISTER (ADDRESS: 10h) R/W-0 R/W-0 T1GINV R/W-0 R/W-0 R/W-0 TMR1GE T1CKPS1 T1CKPS0 T1OSCEN R/W-0 R/W-0 R/W-0 T1SYNC TMR1CS TMR1ON bit 7 bit 0 bit 7 T1GINV: Timer1 Gate Invert bit(1) 1 = Timer1 gate is inverted 0 = Timer1 gate is not inverted bit 6 TMR1GE: Timer1 Gate Enable bit(2) If TMR1ON = 0: This bit is ignored If TMR1ON = 1: 1 = Timer1 is on if Timer1 gate is not active 0 = Timer1 is on bit 5-4 T1CKPS<1:0>: Timer1 Input Clock Prescale Select bits 11 = 1:8 Prescale Value 10 = 1:4 Prescale Value 01 = 1:2 Prescale Value 00 = 1:1 Prescale Value bit 3 T1OSCEN: LP Oscillator Enable Control bit If INTOSC without CLKOUT oscillator is active: 1 = LP oscillator is enabled for Timer1 clock 0 = LP oscillator is off Else: This bit is ignored bit 2 T1SYNC: Timer1 External Clock Input Synchronization Control bit TMR1CS = 1: 1 = Do not synchronize external clock input 0 = Synchronize external clock input TMR1CS = 0: This bit is ignored. Timer1 uses the internal clock. bit 1 TMR1CS: Timer1 Clock Source Select bit 1 = External clock from T1CKI pin (on the rising edge) 0 = Internal clock (FOSC/4) bit 0 TMR1ON: Timer1 On bit 1 = Enables Timer1 0 = Stops Timer1 Note 1: T1GINV bit inverts the Timer1 gate logic, regardless of source. 2: TMR1GE bit must be set to use either T1G pin or C2OUT, as selected by the T1GSS bit (CMCON1<1>), as a Timer1 gate source. Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 51 PIC16F684 6.5 Timer1 Operation in Asynchronous Counter Mode 6.6 A crystal oscillator circuit is built-in between pins OSC1 (input) and OSC2 (amplifier output). It is enabled by setting control bit, T1OSCEN (T1CON<3>). The oscillator is a low-power oscillator rated up to 32 kHz. It will continue to run during Sleep. It is primarily intended for a 32 kHz crystal. Table 3-1 shows the capacitor selection for the Timer1 oscillator. If control bit T1SYNC (T1CON<2>) is set, the external clock input is not synchronized. The timer continues to increment asynchronous to the internal phase clocks. The timer will continue to run during Sleep and can generate an interrupt on overflow, which will wake-up the processor. However, special precautions in software are needed to read/write the timer (see Section 6.5.1 “Reading and Writing Timer1 in Asynchronous Counter Mode”). Note: 6.5.1 The Timer1 oscillator is shared with the system LP oscillator. Thus, Timer1 can use this mode only when the primary system clock is derived from the internal oscillator. As with the system LP oscillator, the user must provide a software time delay to ensure proper oscillator start-up. The ANSEL (91h) and CMCON0 (19h) registers must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read ‘0’. TRISA5 and TRISA4 bits are set when the Timer1 oscillator is enabled. RA5 and RA4 read as ‘0’ and TRISA5 and TRISA4 bits read as ‘1’. READING AND WRITING TIMER1 IN ASYNCHRONOUS COUNTER MODE Note: Reading TMR1H or TMR1L while the timer is running from an external asynchronous clock will ensure a valid read (taken care of in hardware). However, the user should keep in mind that reading the 16-bit timer in two 8-bit values itself, poses certain problems, since the timer may overflow between the reads. 6.7 Timer1 Operation During Sleep • Timer1 must be on (T1CON<0>) • TMR1IE bit (PIE1<0>) must be set • PEIE bit (INTCON<6>) must be set Reading the 16-bit value requires some care. Examples in the “PICmicro® Mid-Range MCU Family Reference Manual” (DS33023) show how to read and write Timer1 when it is running in Asynchronous mode. The device will wake-up on an overflow. If the GIE bit (INTCON<7>) is set, the device will wake-up and jump to the Interrupt Service Routine (0004h) on an overflow. If the GIE bit is clear, execution will continue with the next instruction. REGISTERS ASSOCIATED WITH TIMER1 Value on all other Resets Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOD INTCON GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 0000 0000 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF Addr 0Bh/ 8Bh The oscillator requires a start-up and stabilization time before use. Thus, T1OSCEN should be set and a suitable delay observed prior to enabling Timer 1. Timer1 can only operate during Sleep when setup in Asynchronous Counter mode. In this mode, an external crystal or clock source can be used to increment the counter. To set up the timer to wake the device: For writes, it is recommended that the user simply stop the timer and write the desired values. A write contention may occur by writing to the timer registers, while the register is incrementing. This may produce an unpredictable value in the timer register. TABLE 6-1: Timer1 Oscillator TMR1IF 0000 0000 0000 0000 0Ch PIR1 0Eh TMR1L Holding register for the Least Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu 0Fh TMR1H Holding register for the Most Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu T1GINV TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0000 0000 uuuu uuuu 10h T1CON 1Ah CMCON1 8Ch PIE1 Legend: — — — — — — T1GSS C2SYNC ---- --10 ---- --10 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE TMR1IE 0000 0000 0000 0000 x = unknown, u = unchanged, — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module. DS41202C-page 52 Preliminary 2004 Microchip Technology Inc. PIC16F684 7.0 TIMER2 MODULE 7.1 The Timer2 module timer has the following features: • • • • • • 8-bit timer (TMR2 register) 8-bit period register (PR2) Readable and writable (both registers) Software programmable prescaler (1:1, 1:4, 1:16) Software programmable postscaler (1:1 to 1:16) Interrupt on TMR2 match with PR2 Timer2 has a control register shown in Register 7-1. TMR2 can be shut-off by clearing control bit, TMR2ON (T2CON<2>), to minimize power consumption. Figure 7-1 is a simplified block diagram of the Timer2 module. The prescaler and postscaler selection of Timer2 are controlled by this register. Timer2 Operation Timer2 can be used as the PWM time base for the PWM mode of the ECCP module. The TMR2 register is readable and writable, and is cleared on any device Reset. The input clock (FOSC/4) has a prescale option of 1:1, 1:4 or 1:16, selected by control bits T2CKPS<1:0> (T2CON<1:0>). The match output of TMR2 goes through a 4-bit postscaler (which gives a 1:1 to 1:16 scaling inclusive) to generate a TMR2 interrupt (latched in flag bit, TMR2IF (PIR1<1>)). The prescaler and postscaler counters are cleared when any of the following occurs: • A write to the TMR2 register • A write to the T2CON register • Any device Reset (Power-on Reset, MCLR Reset, Watchdog Timer Reset, or Brown-out Reset) TMR2 is not cleared when T2CON is written. REGISTER 7-1: T2CON — TIMER2 CONTROL REGISTER (ADDRESS: 12h) U-0 R/W-0 R/W-0 R/W-0 R/W-0 — TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 R/W-0 R/W-0 TMR2ON T2CKPS1 R/W-0 T2CKPS0 bit 7 bit 0 bit 7 Unimplemented: Read as ‘0’ bit 6-3 TOUTPS<3:0>: Timer2 Output Postscale Select bits 0000 =1:1 postscale 0001 =1:2 postscale • • • 1111 =1:16 postscale bit 2 TMR2ON: Timer2 On bit 1 =Timer2 is on 0 =Timer2 is off bit 1-0 T2CKPS<1:0>: Timer2 Clock Prescale Select bits 00 = Prescaler is 1 01 = Prescaler is 4 1x = Prescaler is 16 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 53 PIC16F684 7.2 Timer2 Interrupt The Timer2 module has an 8-bit period register, PR2. Timer2 increments from 00h until it matches PR2 and then resets to 00h on the next increment cycle. PR2 is a readable and writable register. The PR2 register is initialized to FFh upon Reset. FIGURE 7-1: TIMER2 BLOCK DIAGRAM Sets Flag bit TMR2IF TMR2 Output Prescaler 1:1, 1:4, 1:16 FOSC/4 2 Reset TMR2 Postscaler 1:1 to 1:16 Comparator EQ T2CKPS<1:0> 4 PR2 TOUTPS<3:0> TABLE 7-1: Value on all other Resets Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOD INTCON GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 0000 0000 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF TMR1IF 0000 0000 0000 0000 Addr 0Bh/ 8Bh REGISTERS ASSOCIATED WITH TIMER2 0Ch PIR1 11h TMR2 12h T2CON 8Ch PIE1 92h PR2 Legend: Holding register for the 8-bit TMR2 register — TOUTPS3 TOUTPS2 TOUTPS1 EEIE ADIE CCP1IE C2IE 0000 0000 0000 0000 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000 C1IE Timer2 Module Period register OSFIE TMR2IE TMR1IE 0000 0000 0000 0000 1111 1111 1111 1111 x = unknown, u = unchanged, — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module. DS41202C-page 54 Preliminary 2004 Microchip Technology Inc. PIC16F684 8.0 COMPARATOR MODULE The comparator module contains two analog comparators. The inputs to the comparators are multiplexed with I/O port pins RA0, RA1, RC0 and RC1, while the outputs are multiplexed to pins RA2 and RC4. An on-chip Comparator Voltage Reference (CVREF) can also be applied to the inputs of the comparators. REGISTER 8-1: The CMCON0 register (Register 8-1) controls the comparator input and output multiplexers. A block diagram of the various comparator configurations is shown in Figure 8-3. CMCON0 – COMPARATOR CONFIGURATION REGISTER (ADDRESS: 19h) R-0 R-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 C2OUT C1OUT C2INV C1INV CIS CM2 CM1 CM0 bit 7 bit 0 bit 7 C2OUT: Comparator 2 Output bit When C2INV = 0: 1 = C2 VIN+ > C2 VIN0 = C2 VIN+ < C2 VINWhen C2INV = 1: 1 = C2 VIN+ < C2 VIN0 = C2 VIN+ > C2 VIN- bit 6 C1OUT: Comparator 1 Output bit When C1INV = 0: 1 = C1 VIN+ > C1 VIN0 = C1 VIN+ < C1 VINWhen C1INV = 1: 1 = C1 VIN+ < C1 VIN0 = C1 VIN+ > C1 VIN- bit 5 C2INV: Comparator 2 Output Inversion bit 1 = C2 output inverted 0 = C2 output not inverted bit 4 C1INV: Comparator 1 Output Inversion bit 1 = C1 Output inverted 0 = C1 Output not inverted bit 3 CIS: Comparator Input Switch bit When CM<2:0> = 010: 1 = C1 VIN- connects to RA0/AN0 C2 VIN- connects to RC0/AN4 0 = C1 VIN- connects to RA1/AN1 C2 VIN- connects to RC1/AN5 When CM<2:0> = 001: 1 = C1 VIN- connects to RA0/AN0 0 = C1 VIN- connects to RA1/AN1 bit 2-0 CM<2:0>: Comparator Mode bits Figure 8-3 shows the Comparator modes and CM<2:0> bit settings Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 55 PIC16F684 8.1 FIGURE 8-1: Comparator Operation A single comparator is shown in Figure 8-1 along with the relationship between the analog input levels and the digital output. When the analog input at VIN+ is less than the analog input VIN-, the output of the comparator is a digital low level. When the analog input at VIN+ is greater than the analog input VIN-, the output of the comparator is a digital high level. The shaded areas of the output of the comparator in Figure 8-1 represent the uncertainty due to input offsets and response time. Note: CxOUT VIN- > VIN+ 0 0 VIN- < VIN+ 0 1 VIN- > VIN+ 1 1 VIN- < VIN+ 1 0 VIN- – Output Output Output 8.2 Analog Input Connection Considerations A simplified circuit for an analog input is shown in Figure 8-2. Since the analog pins are connected to a digital output, they have reverse biased diodes to VDD and VSS. The analog input, therefore, must be between VSS and VDD. If the input voltage deviates from this range by more than 0.6V in either direction, one of the diodes is forward biased and a latch-up may occur. A maximum source impedance of 10 kΩ is recommended for the analog sources. Any external component connected to an analog input pin, such as a capacitor or a Zener diode, should have very little leakage current. OUTPUT STATE VS. INPUT CONDITIONS CINV + VV ININ+ + The polarity of the comparator output can be inverted by setting the CxINV bits (CMCON0<5:4>). Clearing CxINV results in a non-inverted output. A complete table showing the output state versus input conditions and the polarity bit is shown in Table 8-1. Input Conditions VIN+ VIN VIN– To use CIN+ and CIN- pins as analog inputs, the appropriate bits must be programmed in the CMCON0 (19h) register. TABLE 8-1: SINGLE COMPARATOR Note 1: When reading the PORT register, all pins configured as analog inputs will read as a ‘0’. Pins configured as digital inputs will convert as analog inputs according to the input specification. 2: Analog levels on any pin defined as a digital input may cause the input buffer to consume more current than is specified. FIGURE 8-2: ANALOG INPUT MODEL VDD VT = 0.6V Rs < 10K RIC AIN VA CPIN 5 pF VT = 0.6V Leakage ±500 nA Vss Legend: CPIN VT ILEAKAGE RIC RS VA DS41202C-page 56 = = = = = = Input Capacitance Threshold Voltage Leakage Current at the pin due to various junctions Interconnect Resistance Source Impedance Analog Voltage Preliminary 2004 Microchip Technology Inc. PIC16F684 8.3 Comparator Configuration There are eight modes of operation for the comparators. The CMCON0 register is used to select these modes. Figure 8-3 shows the eight possible modes. If the Comparator mode is changed, the comparator output level may not be valid for the specified mode change delay shown in Section 15.0 “Electrical Specifications”. Note: FIGURE 8-3: COMPARATOR I/O OPERATING MODES Comparators Reset (POR Default Value) CM<2:0> = 000 A VINRA1/AN1 RA0/AN0 RC1/AN5 RC0/AN4 A VIN+ A VIN- A VIN+ Comparators Off (Lowest Power) CM<2:0> = 111 D VINRA1/AN1 C1 Off (Read as ‘0’) C2 Off (Read as ‘0’) RC1/AN5 RC0/AN4 A VIN+ A VIN- A VIN+ RA0/AN0 RC1/AN5 C1 RC0/AN4 RA1/AN1 C1OUT RA0/AN0 RC1/AN5 C2 D VIN+ D VIN- D VIN+ C1 Off (Read as ‘0’) C2 Off (Read as ‘0’) Four Inputs Multiplexed to Two Comparators CM<2:0> = 010 Two Independent Comparators CM<2:0> = 100 A VINRA1/AN1 RA0/AN0 Comparator interrupts should be disabled during a Comparator mode change. Otherwise, a false interrupt may occur. RC0/AN4 C2OUT A A CIS = 0 CIS = 1 VIN- CIS = 0 CIS = 1 VIN- VIN+ C1 C1OUT C2 C2OUT A A VIN+ From CVREF Module Two Common Reference Comparators CM<2:0> = 011 A VINRA1/AN1 RA0/AN0 RC1/AN5 RC0/AN4 D VIN+ A VIN- A VIN+ C1 Two Common Reference Comparators with Outputs CM<2:0> = 110 A VINRA1/AN1 C1OUT RA2/C1OUT D RC1/AN5 C2 C2OUT RC0/AN4 VIN+ A VIN- A VIN+ C1 C1OUT C2 C2OUT RC4/C2OUT One Independent Comparator CM<2:0> = 101 D VINRA1/AN1 RA0/AN0 RC1/AN5 RC0/AN4 D A A VIN+ C1 Three Inputs Multiplexed to Two Comparators CM<2:0> = 001 Off (Read as ‘0’) RA0/AN0 VINVIN+ RA1/AN1 C2 RC1/AN5 C2OUT RC0/AN4 Legend: A = Analog Input, ports always read ‘0’ D = Digital Input 2004 Microchip Technology Inc. A A CIS = 0 CIS = 1 VINVIN+ A VIN- A VIN+ C1 C1OUT C2 C2OUT CIS (CMCON0<3>) is the Comparator Input Switch Preliminary DS41202C-page 57 PIC16F684 FIGURE 8-4: INVERTIBLE COMPARATOR C1 OUTPUT BLOCK DIAGRAM MULTIPLEX Port Pins C1INV To C1OUT pin To Data Bus Q D Q3 EN RD CMCON Set C1IF bit Q D RD CMCON EN CL NRESET FIGURE 8-5: INVERTIBLE COMPARATOR C2 OUTPUT BLOCK DIAGRAM MULTIPLEX Port Pins C2INV C2SYNC To TMR1 0 To C2OUT pin 1 Q D TMR1 Clock Source(1) EN To Data Bus Q D Q3 EN RD CMCON Set C2IF bit Q D RD CMCON EN CL Reset Note 1: DS41202C-page 58 Comparator 2 output is latched on falling edge of T1 clock source. Preliminary 2004 Microchip Technology Inc. PIC16F684 REGISTER 8-2: CMCON1 – COMPARATOR CONFIGURATION REGISTER (ADDRESS: 1Ah) U-0 U-0 U-0 U-0 U-0 U-0 R/W-1 R/W-0 — — — — — — T1GSS C2SYNC bit 7 bit 0 bit 7-2: Unimplemented: Read as ‘0’ bit 1 T1GSS: Timer1 Gate Source Select bit 1 = Timer1 gate source is T1G pin (RA4 must be configured as digital input) 0 = Timer1 gate source is comparator 2 output bit 0 C2SYNC: Comparator 2 Synchronize bit 1 = C2 output synchronized with falling edge of Timer1 clock 0 = C2 output not synchronized with Timer1 clock Legend: 8.4 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Comparator Outputs 8.5 The comparator outputs are read through the CMCON0 register. These bits are read-only. The comparator outputs may also be directly output to the RA2 and RC4 I/O pins. When enabled, multiplexers in the output path of the RA2 and RC4 pins will switch and the output of each pin will be the unsynchronized output of the comparator. The uncertainty of each of the comparators is related to the input offset voltage and the response time given in the specifications. Figure 8-4 and Figure 8-5 show the output block diagram for Comparator 1 and 2. The TRIS bits will still function as an output enable/ disable for the RA2 and RC4 pins while in this mode. The polarity of the comparator outputs can be changed using the C1INV and C2INV bits (CMCON0<5:4>). Timer1 gate source can be configured to use the T1G pin or Comparator 2 output as selected by the T1GSS bit (CMCON1<1>). This feature can be used to time the duration or interval of analog events. The output of Comparator 2 can also be synchronized with Timer1 by setting the C2SYNC bit (CMCON1<0>). When enabled, the output of Comparator 2 is latched on the falling edge of Timer1 clock source. If a prescaler is used with Timer1, Comparator 2 is latched after the prescaler. To prevent a race condition, the Comparator 2 output is latched on the falling edge of the Timer1 clock source and Timer1 increments on the rising edge of its clock source. See the Comparator 2 Block Diagram (Figure 8-5) and the Timer1 Block Diagram (Figure 6-1) for more information. x = Bit is unknown Comparator Interrupts The comparator interrupt flags are set whenever there is a change in the output value of its respective comparator. Software will need to maintain information about the status of the output bits, as read from CMCON0<7:6>, to determine the actual change that has occurred. The CxIF bits, PIR1<4:3>, are the Comparator Interrupt Flags. This bit must be reset in software by clearing it to ‘0’. Since it is also possible to write a ‘1’ to this register, a simulated interrupt may be initiated. The CxIE bits (PIE1<4:3>) and the PEIE bit (INTCON<6>) must be set to enable the interrupts. In addition, the GIE bit must also be set. If any of these bits are cleared, the interrupt is not enabled, though the CxIF bits will still be set if an interrupt condition occurs. The user, in the Interrupt Service Routine, can clear the interrupt in the following manner: a) Any read or write of CMCON0. This will end the mismatch condition. Clear flag bit CxIF. b) A mismatch condition will continue to set flag bit CxIF. Reading CMCON0 will end the mismatch condition and allow flag bit CxIF to be cleared. Note: If a change in the CMCON0 register (CxOUT) should occur when a read operation is being executed (start of the Q2 cycle), then the CxIF (PIR1<4:3>) interrupt flag may not get set. It is recommended to synchronize Comparator 2 with Timer1 by setting the C2SYNC bit when Comparator 2 is used as the Timer1 gate source. This ensures Timer1 does not miss an increment if Comparator 2 changes during an increment. 2004 Microchip Technology Inc. Preliminary DS41202C-page 59 PIC16F684 8.6 8.6.2 Comparator Reference The comparator module also allows the selection of an internally generated voltage reference for one of the comparator inputs. The VRCON register (Register 8-3) controls the voltage reference module shown in Figure 8-6. 8.6.1 VOLTAGE REFERENCE ACCURACY/ERROR The full range of VSS to VDD cannot be realized due to the construction of the module. The transistors on the top and bottom of the resistor ladder network (Figure 8-6) keep CVREF from approaching VSS or VDD. The exception is when the module is disabled by clearing the VREN bit (VRCON<7>). When disabled, the reference voltage is VSS when VR<3:0> is ‘0000’ and the VRR (VRCON<5>) bit is set. This allows the comparators to detect a zero-crossing and not consume CVREF module current. CONFIGURING THE VOLTAGE REFERENCE The voltage reference can output 32 distinct voltage levels, 16 in a high range and 16 in a low range. The following equation determines the output voltages: The voltage reference is VDD derived and therefore, the CVREF output changes with fluctuations in VDD. The tested absolute accuracy of the comparator voltage Reference can be found in Section 15.0 “Electrical Specifications”. EQUATION 8-1: VRR = 1 (low range): CVREF = (VR3:VR0/24) X VDD VRR = 0 (high range): CVREF = (VDD/4) + (VR3:VR0 X VDD/32) FIGURE 8-6: COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM 16 Stages 8R R R R R VDD 8R VRR 16-1 Analog MUX VREN CVREF to Comparator Input VR3:VR0 VREN VR3:VR0 = ‘0000’ VRR DS41202C-page 60 Preliminary 2004 Microchip Technology Inc. PIC16F684 8.7 Comparator Response Time 8.9 Response time is the minimum time, after selecting a new reference voltage or input source, before the comparator output is ensured to have a valid level. If the internal reference is changed, the maximum delay of the internal voltage reference must be considered when using the comparator outputs. Otherwise, the maximum delay of the comparators should be used (Table 15-8). 8.8 Effects of a Reset A device Reset forces the CMCON0, CMCON1 and VRCON registers to their Reset states. This forces the comparator module to be in the Comparator Reset mode, CM<2:0> = 000 and the voltage reference to its off state. Thus, all potential inputs are analog inputs with the comparator and voltage reference disabled to consume the smallest current possible. Operation During Sleep The comparators and voltage reference, if enabled before entering Sleep mode, remain active during Sleep. This results in higher Sleep currents than shown in the power-down specifications. The additional current consumed by the comparator and the voltage reference is shown separately in the specifications. To minimize power consumption while in Sleep mode, turn off the comparator, CM<2:0> = 111, and voltage reference, VRCON<7> = 0. While the comparator is enabled during Sleep, an interrupt will wake-up the device. If the GIE bit (INTCON<7>) is set, the device will jump to the interrupt vector (0004h), and if clear, continues execution with the next instruction. If the device wakes up from Sleep, the contents of the CMCON0, CMCON1 and VRCON registers are not affected. 2004 Microchip Technology Inc. Preliminary DS41202C-page 61 PIC16F684 REGISTER 8-3: VRCON – VOLTAGE REFERENCE CONTROL REGISTER (ADDRESS: 99h) R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 VREN — VRR — VR3 VR2 VR1 VR0 bit 7 bit 0 bit 7 VREN: CVREF Enable bit 1 = CVREF circuit powered on 0 = CVREF circuit powered down, no IDD drain and CVREF = VSS bit 6 Unimplemented: Read as ‘0’ bit 5 VRR: CVREF Range Selection bit 1 = Low range 0 = High range bit 4 Unimplemented: Read as ‘0’ bit 3-0 VR<3:0>: CVREF Value Selection 0 ≤ VR<3:0> ≤ 15 When VRR = 1: CVREF = (VR<3:0>/24) * VDD When VRR = 0: CVREF = VDD/4 + (VR<3:0>/32) * VDD Legend: TABLE 8-2: Address R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown REGISTERS ASSOCIATED WITH COMPARATOR MODULE Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOD Value on all other Resets 0Bh/8Bh INTCON GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 0000 0000 0Ch PIR1 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF TMR1IF 0000 0000 0000 0000 0000 0000 19h CMCON0 C2OUT C1OUT C2INV C1INV CIS CM2 CM1 CM0 0000 0000 1Ah CMCON1 — — — — — — T1GSS C2SYNC ---- --10 ---- --10 85h TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111 --11 1111 --11 1111 87h TRISC — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 --11 1111 8Ch PIE1 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE TMR1IE 0000 0000 0000 0000 99h VRCON VREN — VRR — VR3 VR2 VR1 VR0 0-0- 0000 0-0- 0000 Legend: x = unknown, u = unchanged, — = unimplemented, read as ‘0’. Shaded cells are not used by the Capture, Compare or Timer1 module. DS41202C-page 62 Preliminary 2004 Microchip Technology Inc. PIC16F684 9.0 ANALOG-TO-DIGITAL CONVERTER (A/D) MODULE circuit. The output of the sample and hold is connected to the input of the converter. The converter generates a binary result via successive approximation and stores the result in a 10-bit register. The voltage reference used in the conversion is software selectable to either VDD or a voltage applied by the VREF pin. Figure 9-1 shows the block diagram of the A/D on the PIC16F684. The Analog-to-Digital converter (A/D) allows conversion of an analog input signal to a 10-bit binary representation of that signal. The PIC16F684 has eight analog inputs, multiplexed into one sample and hold FIGURE 9-1: A/D BLOCK DIAGRAM VDD VCFG = 0 VREF VCFG = 1 RA0/AN0 RA1/AN1/VREF A/D RA2/AN2 10 GO/DONE RA4/AN3 RC0/AN4 ADFM RC1/AN5 10 ADON RC2/AN6 ADRESH RC3/AN7 ADRESL VSS CHS<2:0> 9.1 A/D Configuration and Operation There are three registers available to control the functionality of the A/D module: 1. 2. 3. ANSEL (Register 9-1) ADCON0 (Register 9-2) ADCON1 (Register 9-3) 9.1.1 9.1.3 VOLTAGE REFERENCE There are two options for the voltage reference to the A/D converter: either VDD is used, or an analog voltage applied to VREF is used. The VCFG bit (ADCON0<6>) controls the voltage reference selection. If VCFG is set, then the voltage on the VREF pin is the reference; otherwise, VDD is the reference. ANALOG PORT PINS The ANS<7:0> bits (ANSEL<7:0>) and the TRIS bits control the operation of the A/D port pins. Set the corresponding TRIS bits to set the pin output driver to its high-impedance state. Likewise, set the corresponding ANSEL bit to disable the digital input buffer. Note: 9.1.2 Analog voltages on any pin that is defined as a digital input may cause the input buffer to conduct excess current. CHANNEL SELECTION There are eight analog channels on the PIC16F684, AN0 through AN7. The CHS<2:0> bits (ADCON0<4:2>) control which channel is connected to the sample and hold circuit. 2004 Microchip Technology Inc. Preliminary DS41202C-page 63 PIC16F684 9.1.4 CONVERSION CLOCK • • • • The A/D conversion cycle requires 11 TAD. The source of the conversion clock is software selectable via the ADCS bits (ADCON1<6:4>). There are seven possible clock options: For correct conversion, the A/D conversion clock (1/TAD) must be selected to ensure a minimum TAD of 1.6 µs. Table 9-1 shows a few TAD calculations for selected frequencies. • FOSC/2 • FOSC/4 • FOSC/8 TABLE 9-1: FOSC/16 FOSC/32 FOSC/64 FRC (dedicated internal oscillator) TAD VS. DEVICE OPERATING FREQUENCIES A/D Clock Source (TAD) Device Frequency Operation ADCS2:ADCS0 20 MHz 5 MHz 4 MHz 1.25 MHz 2 TOSC 000 100 ns(2) 400 ns(2) 500 ns(2) 1.6 µs 4 TOSC 100 200 ns (2) (2) 1.0 µs 3.2 µs 8 TOSC 001 400 ns(2) 1.6 µs 2.0 µs 6.4 µs TOSC 101 800 ns(2) 3.2 µs 4.0 µs 12.8 µs(3) 32 TOSC 010 1.6 µs 6.4 µs 8.0 µs(3) 25.6 µs(3) 64 TOSC 110 3.2 µs 12.8 µs(3) 16.0 µs(3) 51.2 µs(3) µs(1,4) µs(1,4) 2-6 µs(1,4) 16 A/D RC Legend: Note 1: 2: 3: 4: 9.1.5 2-6 x11 800 ns µs(1,4) 2-6 (2) 2-6 Shaded cells are outside of recommended range. The A/D RC source has a typical TAD time of 4 µs for VDD > 3.0V. These values violate the minimum required TAD time. For faster conversion times, the selection of another clock source is recommended. When the device frequency is greater than 1 MHz, the A/D RC clock source is only recommended if the conversion will be performed during Sleep. If the conversion must be aborted, the GO/DONE bit can be cleared in software. The ADRESH:ADRESL registers will not be updated with the partially complete A/D conversion sample. Instead, the ADRESH:ADRESL registers will retain the value of the previous conversion. After an aborted conversion, a 2 TAD delay is required before another acquisition can be initiated. Following the delay, an input acquisition is automatically started on the selected channel. STARTING A CONVERSION The A/D conversion is initiated by setting the GO/DONE bit (ADCON0<1>). When the conversion is complete, the A/D module: • Clears the GO/DONE bit • Sets the ADIF flag (PIR1<6>) • Generates an interrupt (if enabled) Note: FIGURE 9-2: The GO/DONE bit should not be set in the same instruction that turns on the A/D. A/D CONVERSION TAD CYCLES TCY to TAD TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 b9 b8 b7 b6 b5 b4 b3 TAD9 TAD10 TAD11 b2 b1 b0 Conversion Starts Holding Capacitor is Disconnected from Analog Input (typically 100 ns) Set GO bit DS41202C-page 64 ADRESH and ADRESL registers are Loaded, GO bit is Cleared, ADIF bit is Set, Holding Capacitor is Connected to Analog Input Preliminary 2004 Microchip Technology Inc. PIC16F684 9.1.6 CONVERSION OUTPUT The A/D conversion can be supplied in two formats: left or right shifted. The ADFM bit (ADCON0<7>) controls the output format. Figure 9-3 shows the output formats. FIGURE 9-3: 10-BIT A/D RESULT FORMAT ADRESH (ADFM = 0) ADRESL MSB LSB bit 7 bit 0 bit 7 bit 0 10-bit A/D Result Unimplemented: Read as ‘0’ MSB (ADFM = 1) bit 7 LSB bit 0 Unimplemented: Read as ‘0’ REGISTER 9-1: bit 7 bit 0 10-bit A/D Result ANSEL – ANALOG SELECT REGISTER (ADDRESS: 91h) R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 ANS7 ANS6 ANS5 ANS4 ANS3 ANS2 ANS1 ANS0 bit 7 bit 7-0: bit 0 ANS<7:0>: Analog Select bits Analog select between analog or digital function on pins AN<7:0>, respectively. 1 = Analog input. Pin is assigned as analog input(1). 0 = Digital I/O. Pin is assigned to port or special function. Note 1: Setting a pin to an analog input automatically disables the digital input circuitry, weak pull-ups, and interrupt-on-change if available. The corresponding TRIS bit must be set to input mode in order to allow external control of the voltage on the pin. Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 65 PIC16F684 REGISTER 9-2: ADCON0 – A/D CONTROL REGISTER (ADDRESS: 1Fh) R/W-0 R/W-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 ADFM VCFG — CHS2 CHS1 CHS0 GO/DONE ADON bit 7 bit 0 bit 7 ADFM: A/D Result Formed Select bit 1 = Right justified 0 = Left justified bit 6 VCFG: Voltage Reference bit 1 = VREF pin 0 = VDD bit 5 Unimplemented: Read as ‘0’ bit 4-2 CHS<2:0>: Analog Channel Select bits 000 = Channel 00 (AN0) 001 = Channel 01 (AN1) 010 = Channel 02 (AN2) 011 = Channel 03 (AN3) 100 = Channel 04 (AN4) 101 = Channel 05 (AN5) 110 = Channel 06 (AN6) 111 = Channel 07 (AN7) bit 1 GO/DONE: A/D Conversion Status bit 1 = A/D conversion cycle in progress. Setting this bit starts an A/D conversion cycle. This bit is automatically cleared by hardware when the A/D conversion has completed. 0 = A/D conversion completed/not in progress bit 0 ADON: A/D Conversion Status bit 1 = A/D converter module is operating 0 = A/D converter is shut-off and consumes no operating current Legend: REGISTER 9-3: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown ADCON1 – A/D CONTROL REGISTER 1 (ADDRESS: 9Fh) U-0 R/W-0 R/W-0 R/W-0 U-0 U-0 U-0 U-0 — ADCS2 ADCS1 ADCS0 — — — — bit 7 bit 0 bit 7: Unimplemented: Read as ‘0’ bit 6-4: ADCS<2:0>: A/D Conversion Clock Select bits 000 = FOSC/2 001 = FOSC/8 010 = FOSC/32 x11 = FRC (clock derived from a dedicated internal oscillator = 500 kHz max) 100 = FOSC/4 101 = FOSC/16 110 = FOSC/64 bit 3-0: Unimplemented: Read as ‘0’ Legend: DS41202C-page 66 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 9.1.7 CONFIGURING THE A/D EXAMPLE 9-1: After the A/D module has been configured as desired, the selected channel must be acquired before the conversion is started. The analog input channels must have their corresponding TRIS bits selected as inputs. To determine sample time, see Section 15.0 “Electrical Specifications”. After this sample time has elapsed, the A/D conversion can be started. These steps should be followed for an A/D conversion: 1. 2. 3. 4. 5. 6. 7. Configure the A/D module: • Configure analog/digital I/O (ANSEL) • Configure voltage reference (ADCON0) • Select A/D input channel (ADCON0) • Select A/D conversion clock (ADCON1) • Turn on A/D module (ADCON0) Configure A/D interrupt (if desired): • Clear ADIF bit (PIR1<6>) • Set ADIE bit (PIE1<6>) • Set PEIE and GIE bits (INTCON<7:6>) Wait the required acquisition time. Start conversion: • Set GO/DONE bit (ADCON0<0>) Wait for A/D conversion to complete, by either: • Polling for the GO/DONE bit to be cleared (with interrupts disabled); OR • Waiting for the A/D interrupt Read A/D Result register pair (ADRESH:ADRESL), clear bit ADIF if required. For next conversion, go to step 1 or step 2 as required. The A/D conversion time per bit is defined as TAD. A minimum wait of 2 TAD is required before the next acquisition starts. 2004 Microchip Technology Inc. A/D CONVERSION ;This code block configures the A/D ;for polling, Vdd reference, R/C clock ;and RA0 input. ; ;Conversion start & wait for complete ;polling code included. ; BSF STATUS,RP0 ;Bank 1 MOVLW B’01110000’ ;A/D RC clock MOVWF ADCON1 BSF TRISA,0 ;Set RA0 to input BSF ANSEL,0 ;Set RA0 to analog BCF STATUS,RP0 ;Bank 0 MOVLW B’10000001’ ;Right, Vdd Vref, AN0 MOVWF ADCON0 CALL SampleTime ;Wait min sample time BSF ADCON0,GO ;Start conversion BTFSC ADCON0,GO ;Is conversion done? GOTO $-1 ;No, test again MOVF ADRESH,W ;Read upper 2 bits MOVWF RESULTHI BSF STATUS,RP0 ;Bank 1 MOVF ADRESL,W ;Read lower 8 bits MOVWF RESULTLO Preliminary DS41202C-page 67 PIC16F684 9.2 A/D Acquisition Requirements For the A/D converter to meet its specified accuracy, the charge holding capacitor (CHOLD) must be allowed to fully charge to the input channel voltage level. The analog input model is shown in Figure 9-4. The source impedance (RS) and the internal sampling switch (RSS) impedance directly affect the time required to charge the capacitor CHOLD. The sampling switch (RSS) impedance varies over the device voltage (VDD), see Figure 9-4. The maximum recommended impedance for analog sources is 10 kΩ. As the impedance is decreased, the acquisition time may be decreased. EQUATION 9-1: After the analog input channel is selected (changed), this acquisition must be done before the conversion can be started. To calculate the minimum acquisition time, Equation 9-1 may be used. This equation assumes that 1/2 LSb error is used (1024 steps for the A/D). The 1/2 LSb error is the maximum error allowed for the A/D to meet its specified resolution. To calculate the minimum acquisition time, TACQ, see the “PICmicro® Mid-Range MCU Family Reference Manual” (DS33023). ACQUISITION TIME TACQ = Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient = TAMP + TC + TCOFF = 2 µs + TC + [(Temperature -25°C)(0.05 µs/°C)] TC = CHOLD (RIC + RSS + RS) In(1/2047) = -120 pF (1 kΩ + 7 kΩ + 10 kΩ) In(0.0004885) = 16.47 µs TACQ = 2 µs + 16.47 µs + [(50°C-25°C)(0.05 µs/°C)] = 19.72 µs Note 1: The reference voltage (VREF) has no effect on the equation, since it cancels itself out. 2: The charge holding capacitor (CHOLD) is not discharged after each conversion. 3: The maximum recommended impedance for analog sources is 10 kΩ. This is required to meet the pin leakage specification. FIGURE 9-4: ANALOG INPUT MODEL VDD RS VA ANx CPIN 5 pF VT = 0.6V VT = 0.6V RIC ≤ 1k Sampling Switch SS RSS CHOLD = DAC capacitance = 120 pF I LEAKAGE ± 500 nA VSS Legend: CPIN = Input Capacitance VT = Threshold Voltage I LEAKAGE = Leakage Current at the pin due to various junctions RIC = Interconnect Resistance SS = Sampling Switch CHOLD = Sample/Hold Capacitance (from DAC) DS41202C-page 68 Preliminary 6V 5V VDD 4V 3V 2V 5 6 7 8 9 10 11 Sampling Switch (kΩ) 2004 Microchip Technology Inc. PIC16F684 9.3 A/D Operation During Sleep The A/D converter module can operate during Sleep. This requires the A/D clock source to be set to the internal oscillator. When the RC clock source is selected, the A/D waits one instruction before starting the conversion. This allows the SLEEP instruction to be executed, thus eliminating much of the switching noise from the conversion. When the conversion is complete, the GO/DONE bit is cleared and the result is loaded into the ADRESH:ADRESL registers. FIGURE 9-5: If the A/D interrupt is enabled, the device awakens from Sleep. If the GIE bit (INTCON<7>) is set, the program counter is set to the interrupt vector (0004h), if GIE is clear, the next instruction is executed. If the A/D interrupt is not enabled, the A/D module is turned off, although the ADON bit remains set. When the A/D clock source is something other than RC, a SLEEP instruction causes the present conversion to be aborted, and the A/D module is turned off. The ADON bit remains set. A/D TRANSFER FUNCTION Full-Scale Range 3FFh 3FEh A/D Output Code 3FDh 3FCh 1 LSB ideal 3FBh Full-Scale Transition 004h 003h 002h 001h 000h Analog Input Voltage 1 LSB ideal 0V 9.4 Effects of Reset A device Reset forces all registers to their Reset state. Thus, the A/D module is turned off and any pending conversion is aborted. The ADRESH:ADRESL registers are unchanged. 9.5 Use of the ECCP Trigger An A/D conversion can be started by the “special event trigger” of the ECCP module. This requires that the CCP1M3:CCP1M0 bits (CCP1CON<3:0>) be programmed as ‘1011’ and that the A/D module is enabled (ADON bit is set). When the trigger occurs, the GO/DONE bit will be set, starting the A/D conversion and the Timer1 counter will be reset to zero. Timer1 is reset to automatically repeat the A/D acquisition period with minimal software overhead (moving the ADRESH:ADRESL to the desired location). 2004 Microchip Technology Inc. VREF Zero-Scale Transition The appropriate analog input channel must be selected and the minimum acquisition done before the “special event trigger” sets the GO/DONE bit (starts a conversion). If the A/D module is not enabled (ADON is cleared), then the “special event trigger” will be ignored by the A/D module, but will still reset the Timer1 counter. See Section 11.0 “Enhanced Capture/Compare/PWM (ECCP) Module” for more information. Preliminary DS41202C-page 69 PIC16F684 TABLE 9-2: Addr Name SUMMARY OF A/D REGISTERS Value on all other Resets Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on: POR, BOD — — RA5 RA4 RA3 RA2 RA1 RA0 --xx xxxx --uu uuuu 05h PORTA 07h PORTC — — RC5 RC4 RC3 RC2 RC1 RC0 --xx xxxx --uu uuuu 0Bh/ 8Bh INTCON GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 0000 0000 0Ch PIR1 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF 1Eh ADRESH Most Significant 8 bits of the left shifted A/D result or 2 bits of the right shifted result xxxx xxxx uuuu uuuu 1Fh ADCON0 00-0 0000 00-0 0000 ADFM VCFG — CHS2 CHS1 CHS0 GO/DONE TMR1IF 0000 0000 0000 0000 ADON 85h TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111 --11 1111 87h TRISC — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 --11 1111 --11 1111 TMR1IE 0000 0000 0000 0000 8Ch PIE1 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE 91h ANSEL ANS7 ANS6 ANS5 ANS4 ANS3 ANS2 ANS1 ANS0 9Eh ADRESL Least Significant 2 bits of the left shifted A/D result or 8 bits of the right shifted result 9Fh ADCON1 — ADCS2 ADCS1 ADCS0 — — — 1111 1111 1111 1111 xxxx xxxx uuuu uuuu — -000 ---- -000 ---- Legend: x = unknown, u = unchanged, — = unimplemented read as ‘0’. Shaded cells are not used for A/D module. DS41202C-page 70 Preliminary 2004 Microchip Technology Inc. PIC16F684 10.0 DATA EEPROM MEMORY The EEPROM data memory is readable and writable during normal operation (full VDD range). This memory is not directly mapped in the register file space. Instead, it is indirectly addressed through the Special Function Registers. There are four SFRs used to read and write this memory: • • • • EECON1 EECON2 (not a physically implemented register) EEDAT EEADR EEDAT holds the 8-bit data for read/write, and EEADR holds the address of the EEPROM location being accessed. PIC16F684 has 256 bytes of data EEPROM with an address range from 0h to FFh. REGISTER 10-1: The EEPROM data memory allows byte read and write. A byte write automatically erases the location and writes the new data (erase before write). The EEPROM data memory is rated for high erase/write cycles. The write time is controlled by an on-chip timer. The write time will vary with voltage and temperature as well as from chip-to-chip. Please refer to AC Specifications in Section 15.0 “Electrical Specifications” for exact limits. When the data memory is code-protected, the CPU may continue to read and write the data EEPROM memory. The device programmer can no longer access the data EEPROM data and will read zeroes. Additional information on the data EEPROM is available in the “PICmicro® Mid-Range MCU Family Reference Manual” (DS33023). EEDAT – EEPROM DATA REGISTER (ADDRESS: 9Ah) R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 EEDAT7 EEDAT6 EEDAT5 EEDAT4 EEDAT3 R/W-0 R/W-0 EEDAT2 EEDAT1 R/W-0 EEDAT0 bit 7 bit 7-0 bit 0 EEDATn: Byte Value to Write to or Read From Data EEPROM bits Legend: REGISTER 10-2: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown EEADR – EEPROM ADDRESS REGISTER (ADDRESS: 9Bh) R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 EEADR7 EEADR6 EEADR5 EEADR4 EEADR3 R/W-0 R/W-0 bit 7 bit 7-0 R/W-0 EEADR2 EEADR1 EEADR0 bit 0 EEADR: Specifies One of 256 Locations for EEPROM Read/Write Operation bits Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 71 PIC16F684 10.1 EECON1 and EECON2 Registers EECON1 is the control register with four low-order bits physically implemented. The upper four bits are nonimplemented and read as ‘0’s. Control bits RD and WR initiate read and write, respectively. These bits cannot be cleared, only set in software. They are cleared in hardware at completion of the read or write operation. The inability to clear the WR bit in software prevents the accidental, premature termination of a write operation. can check the WRERR bit, clear it and rewrite the location. The data and address will be cleared. Therefore, the EEDAT and EEADR registers will need to be re-initialized. Interrupt flag, EEIF bit (PIR1<7>), is set when write is complete. This bit must be cleared in software. EECON2 is not a physical register. Reading EECON2 will read all ‘0’s. The EECON2 register is used exclusively in the data EEPROM write sequence. Note: The WREN bit, when set, will allow a write operation. On power-up, the WREN bit is clear. The WRERR bit is set when a write operation is interrupted by a MCLR Reset, or a WDT Time-out Reset during normal operation. In these situations, following Reset, the user REGISTER 10-3: The EECON1, EEDAT and EEADR registers should not be modified during a data EEPROM write (WR bit = 1). EECON1 – EEPROM CONTROL REGISTER (ADDRESS: 9Ch) U-0 U-0 U-0 U-0 R/W-x R/W-0 R/S-0 R/S-0 — — — — WRERR WREN WR RD bit 7 bit 0 bit 7-4 Unimplemented: Read as ‘0’ bit 3 WRERR: EEPROM Error Flag bit 1 = A write operation is prematurely terminated (any MCLR Reset, any WDT Reset during normal operation or BOD detect) 0 = The write operation completed bit 2 WREN: EEPROM Write Enable bit 1 = Allows write cycles 0 = Inhibits write to the data EEPROM bit 1 WR: Write Control bit 1 = Initiates a write cycle (The bit is cleared by hardware once write is complete. The WR bit can only be set, not cleared, in software.) 0 = Write cycle to the data EEPROM is complete bit 0 RD: Read Control bit 1 = Initiates an EEPROM read (Read takes one cycle. RD is cleared in hardware. The RD bit can only be set, not cleared, in software.) 0 = Does not initiate an EEPROM read Legend: S = Bit can only be set DS41202C-page 72 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 10.2 Reading the EEPROM Data Memory After a write sequence has been initiated, clearing the WREN bit will not affect this write cycle. The WR bit will be inhibited from being set unless the WREN bit is set. To read a data memory location, the user must write the address to the EEADR register and then set control bit RD (EECON1<0>), as shown in Example 10-1. The data is available, in the very next cycle, in the EEDAT register. Therefore, it can be read in the next instruction. EEDAT holds this value until another read, or until it is written to by the user (during a write operation). EXAMPLE 10-1: BSF MOVLW MOVWF BSF MOVF 10.3 DATA EEPROM READ STATUS,RP0 ;Bank 1 CONFIG_ADDR ; EEADR ;Address to read EECON1,RD ;EE Read EEDAT,W ;Move data to W 10.4 EXAMPLE 10-2: BSF BSF BCF MOVLW MOVWF MOVLW MOVWF BSF BSF DATA EEPROM WRITE STATUS,RP0 EECON1,WREN INTCON,GIE 55h EECON2 AAh EECON2 EECON1,WR INTCON,GIE ;Bank 1 ;Enable write ;Disable INTs ;Unlock write ; ; ; ;Start the write ;Enable INTS The write will not initiate if the above sequence is not exactly followed (write 55h to EECON2, write AAh to EECON2, then set WR bit) for each byte. We strongly recommend that interrupts be disabled during this code segment. A cycle count is executed during the required sequence. Any number that is not equal to the required cycles to execute the required sequence will prevent the data from being written into the EEPROM. Additionally, the WREN bit in EECON1 must be set to enable write. This mechanism prevents accidental writes to data EEPROM due to errant (unexpected) code execution (i.e., lost programs). The user should keep the WREN bit clear at all times, except when updating EEPROM. The WREN bit is not cleared by hardware. 2004 Microchip Technology Inc. Write Verify Depending on the application, good programming practice may dictate that the value written to the data EEPROM should be verified (see Example 10-3) to the desired value to be written. EXAMPLE 10-3: Writing to the EEPROM Data Memory To write an EEPROM data location, the user must first write the address to the EEADR register and the data to the EEDAT register. Then the user must follow a specific sequence to initiate the write for each byte, as shown in Example 10-2. Required Sequence At the completion of the write cycle, the WR bit is cleared in hardware and the EE Write Complete Interrupt Flag bit (EEIF) is set. The user can either enable this interrupt or poll this bit. The EEIF bit (PIR1<7>) register must be cleared by software. WRITE VERIFY BSF MOVF STATUS,RP0 EEDAT,W BSF EECON1,RD XORWF BTFSS GOTO : EEDAT,W STATUS,Z WRITE_ERR 10.4.1 ;Bank 1 ;EEDAT not changed ;from previous write ;YES, Read the ;value written ;Is data the same ;No, handle error ;Yes, continue USING THE DATA EEPROM The data EEPROM is a high-endurance, byte addressable array that has been optimized for the storage of frequently changing information. The maximum endurance for any EEPROM cell is specified as Dxxx. D120 or D120A specify a maximum number of writes to any EEPROM location before a refresh is required of infrequently changing memory locations. 10.4.2 EEPROM ENDURANCE A hypothetical data EEPROM is 64 bytes long and has an endurance of 1M writes. It also has a refresh parameter of 10M writes. If every memory location in the cell were written the maximum number of times, the data EEPROM would fail after 64M write cycles. If every memory location save one were written the maximum number of times, the data EEPROM would fail after 63M write cycles, but the one remaining location could fail after 10M cycles. If proper refreshes occurred, then the lone memory location would have to be refreshed six times for the data to remain correct. Preliminary DS41202C-page 73 PIC16F684 10.5 Protection Against Spurious Write There are conditions when the user may not want to write to the data EEPROM memory. To protect against spurious EEPROM writes, various mechanisms have been built in. On power-up, WREN is cleared. Also, the Power-up Timer (64 ms duration) prevents EEPROM write. The write initiate sequence and the WREN bit together help prevent an accidental write during: • Brown-out • Power Glitch • Software Malfunction TABLE 10-1: Address 10.6 Data EEPROM Operation During Code-Protect Data memory can be code-protected by programming the CPD bit in the Configuration Word register (Register 12-1) to ‘0’. When the data memory is code-protected, the CPU is able to read and write data to the data EEPROM. It is recommended to code-protect the program memory when code-protecting data memory. This prevents anyone from programming zeroes over the existing code (which will execute as NOPs) to reach an added routine, programmed in unused program memory, which outputs the contents of data memory. Programming unused locations in program memory to ‘0’ will also help prevent data memory code protection from becoming breached. REGISTERS/BITS ASSOCIATED WITH DATA EEPROM Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Value on all other Resets Bit 1 Bit 0 Value on POR, BOD INTF RAIF 0000 0000 0000 0000 0Bh/8Bh INTCON GIE PEIE T0IE INTE RAIE T0IF 0Ch PIR1 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF TMR1IF 0000 0000 0000 0000 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE TMR1IE 0000 0000 0000 0000 8Ch PIE1 9Ah EEDAT EEDAT7 EEDAT6 EEDAT5 EEDAT4 EEDAT3 EEDAT2 EEDAT1 EEDAT0 0000 0000 0000 0000 9Bh EEADR EEADR7 EEADR6 EEADR5 EEADR 9Ch EECON1 9Dh EECON2(1) EEPROM Control register 2 Legend: x = unknown, u = unchanged, — = unimplemented read as ‘0’, q = value depends upon condition. Shaded cells are not used by data EEPROM module. EECON2 is not a physical register. Note 1: DS41202C-page 74 — — — — EEADR EEADR EEADR EEADR WRERR WREN WR RD 0000 0000 0000 0000 ---- x000 ---- q000 ---- ---- ---- ---- Preliminary 2004 Microchip Technology Inc. PIC16F684 11.0 ENHANCED CAPTURE/COMPARE/PWM (ECCP) MODULE The CCP1CON register controls the operation of ECCP. The special event trigger is generated by a compare match and will clear both TMR1H and TMR1L registers. The enhanced Capture/Compare/PWM (ECCP) module contains a 16-bit register which can operate as a: TABLE 11-1: • 16-bit Capture register • 16-bit Compare register • PWM Master/Slave Duty Cycle register Capture/Compare/PWM Register 1 (CCPR1) is comprised of two 8-bit registers: CCPR1L (low byte) and CCPR1H (high byte). REGISTER 11-1: bit 5-4 bit 3-0 ECCP Mode Timer Resource Capture Timer1 Compare Timer1 PWM Timer2 CCP1CON — ENHANCED CCP OPERATION REGISTER (ADDRESS: 15h) R/W-0 P1M1 bit 7 bit 7-6 ECCP MODE – TIMER RESOURCES REQUIRED R/W-0 P1M0 R/W-0 DC1B1 R/W-0 DC1B0 R/W-0 CCP1M3 R/W-0 CCP1M2 R/W-0 CCP1M1 R/W-0 CCP1M0 bit 0 P1M<1:0>: PWM Output Configuration bits If CCP1M<3:2> = 00, 01, 10: xx = P1A assigned as Capture/Compare input; P1B, P1C, P1D assigned as port pins If CCP1M<3:2> = 11: 00 = Single output; P1A modulated; P1B, P1C, P1D assigned as port pins 01 = Full-bridge output forward; P1D modulated; P1A active; P1B, P1C inactive 10 = Half-bridge output; P1A, P1B modulated with dead band control; P1C, P1D assigned as port pins 11 = Full-bridge output reverse; P1B modulated; P1C active; P1A, P1D inactive DC1B<1:0>: PWM Duty Cycle Least Significant bits Capture mode: Unused. Compare mode: Unused. PWM mode: These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPR1L. CCP1M<3:0>: ECCP Mode Select bits 0000 = Capture/Compare/PWM off (resets ECCP module) 0001 = Unused (reserved) 0010 = Compare mode, toggle output on match (CCP1IF bit is set) 0011 = Unused (reserved) 0100 = Capture mode, every falling edge 0101 = Capture mode, every rising edge 0110 = Capture mode, every 4th rising edge 0111 = Capture mode, every 16th rising edge 1000 = Compare mode, set output on match (CCP1IF bit is set) 1001 = Compare mode, clear output on match (CCP1IF bit is set) 1010 = Compare mode, generate software interrupt on match (CCP1IF bit is set, CCP1 pin is unaffected) 1011 = Compare mode, trigger special event (CCP1IF bit is set; CCP1 resets TMR1or TMR2, and starts an A/D conversion, if the A/D module is enabled) 1100 = PWM mode; P1A, P1C active-high; P1B, P1D active-high 1101 = PWM mode; P1A, P1C active-high; P1B, P1D active-low 1110 = PWM mode; P1A, P1C active-low; P1B, P1D active-high 1111 = PWM mode; P1A, P1C active-low; P1B, P1D active-low Legend: R = Readable bit -n = Value at POR 2004 Microchip Technology Inc. W = Writable bit ‘1’ = Bit is set Preliminary U = Unimplemented bit, read as ‘0’ ‘0’ = Bit is cleared x = Bit is unknown DS41202C-page 75 PIC16F684 11.1 11.1.4 Capture Mode In Capture mode, CCPR1H:CCPR1L captures the 16-bit value of the TMR1 register when an event occurs on pin RC5/CCP1/P1A. An event is defined as one of the following and is configured by CCP1CON<3:0>: • • • • Every falling edge Every rising edge Every 4th rising edge Every 16th rising edge When a capture is made, the interrupt request flag bit, CCP1IF (PIR1<5>), is set. The interrupt flag must be cleared in software. If another capture occurs before the value in register CCPR1 is read, the old captured value is overwritten by the new captured value. 11.1.1 CCP1 PIN CONFIGURATION In Capture mode, the RC5/CCP1/P1A pin should be configured as an input by setting the TRISC<5> bit. Note: If the RC5/CCP1/P1A pin is configured as an output, a write to the port can cause a capture condition. FIGURE 11-1: Prescaler ÷ 1, 4, 16 ECCP PRESCALER There are four prescaler settings specified by bits CCP1M<3:0> (CCP1CON<3:0>). Whenever the ECCP module is turned off, or the ECCP module is not in Capture mode, the prescaler counter is cleared. Any Reset will clear the prescaler counter. Switching from one capture prescaler to another may generate an interrupt. Also, the prescaler counter will not be cleared; therefore, the first capture may be from a non-zero prescaler. Example 11-1 shows the recommended method for switching between capture prescalers. This example also clears the prescaler counter and will not generate the “false” interrupt. EXAMPLE 11-1: CLRF MOVLW MOVWF CHANGING BETWEEN CAPTURE PRESCALERS CCP1CON ;Turn ECCP module off NEW_CAPT_PS ;Load the W reg with ;the new prescaler ;move value and ECCP ON CCP1CON ;Load CCP1CON with this ;value CAPTURE MODE OPERATION BLOCK DIAGRAM Set Flag bit CCP1IF (PIR1<5>) RC5/CCP1/P1A pin CCPR1H and Edge Detect CCPR1L Capture Enable TMR1H TMR1L CCP1CON<3:0> Q’s 11.1.2 TIMER1 MODE SELECTION Timer1 must be running in Timer mode or Synchronized Counter mode for the ECCP module to use the capture feature. In Asynchronous Counter mode, the capture operation may not work. 11.1.3 SOFTWARE INTERRUPT When the Capture mode is changed, a false capture interrupt may be generated. The user should keep bit CCP1IE (PIE1<5>) clear to avoid false interrupts and should clear the flag bit CCP1IF (PIR1<5>) following any such change in operating mode. DS41202C-page 76 Preliminary 2004 Microchip Technology Inc. PIC16F684 11.2 11.2.1 Compare Mode The user must configure the RC5/CCP1/P1A pin as an output by clearing the TRISC<5> bit. In Compare mode, the 16-bit CCPR1 register value is constantly compared against the TMR1 register pair value. When a match occurs, the RC5/CCP1/P1A pin is: Note: • Driven high • Driven low • Remains unchanged 11.2.2 The action on the pin is based on the value of control bits, CCP1M<3:0> (CCP1CON<3:0>). At the same time, interrupt flag bit, CCP1IF (PIR1<5>), is set. FIGURE 11-2: 11.2.3 Set Flag bit CCP1IF (PIR1<5>) 11.2.4 CCPR1H CCPR1L S R Output Logic Match TMR1L Special Event Trigger will: • clear TMR1H and TMR1L registers • NOT set interrupt flag bit TMR1F (PIR1<0>) • set the GO/DONE bit (ADCON0<1>) Addr 0Bh/ 8Bh SPECIAL EVENT TRIGGER The special event trigger output of ECCP resets the TMR1 register pair. This allows the CCPR1 register to effectively be a 16-bit programmable period register for Timer1. The special event trigger output also starts an A/D conversion (if the A/D module is enabled). Special Event Trigger TABLE 11-2: SOFTWARE INTERRUPT MODE In this mode (CCP1M<3:0> = 1011), an internal hardware trigger is generated, which may be used to initiate an action. See Register 11-1. Comparator TMR1H TRISC<5> Output Enable TIMER1 MODE SELECTION When Generate Software Interrupt mode is chosen (CCP1M<3:0> = 1010), the CCP1 pin is not affected. The CCP1IF (PIR1<5>) bit is set, causing a ECCP interrupt (if enabled). See Register 11-1. CCP1CON<3:0> Mode Select Q Clearing the CCP1CON register will force the RC5/CCP1/P1A compare output latch to the default low level. This is not the PORTC I/O data latch. Timer1 must be running in Timer mode or Synchronized Counter mode if the ECCP module is using the compare feature. In Asynchronous Counter mode, the compare operation may not work. COMPARE MODE OPERATION BLOCK DIAGRAM RC5/CCP1/P1A pin CCP1 PIN CONFIGURATION Note: The special event trigger from the ECCP module will not set interrupt flag bit TMR1IF (PIR1<0>). REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, AND TIMER1 Value on all other Resets Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOD INTCON GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 0000 0000 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF 0Ch PIR1 0Eh TMR1L Holding register for the Least Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu 0Fh TMR1H Holding register for the Most Significant Byte of the 16-bit TMR1 register xxxx xxxx uuuu uuuu 10h T1CON T1GINV TMR1GE T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0000 0000 uuuu uuuu — — — — — — T1GSS TMR1IF 0000 0000 0000 0000 C2SYNC ---- --10 ---- --10 1Ah CMCON1 13h CCPR1L Capture/Compare/PWM Register 1 Low Byte xxxx xxxx uuuu uuuu 14h CCPR1H Capture/Compare/PWM Register 1 High Byte xxxx xxxx uuuu uuuu 15h CCP1CON 87h TRISC 8Ch PIE1 P1M1 P1M0 DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0 0000 0000 0000 0000 — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 --11 1111 --11 1111 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE TMR1IE 0000 0000 0000 0000 Legend: — = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown. Shaded cells are not used by the Capture, Compare or Timer1 module. 2004 Microchip Technology Inc. Preliminary DS41202C-page 77 PIC16F684 11.3 Enhanced PWM Mode Figure 11-3 shows a simplified block diagram of PWM operation. The Enhanced CCP module produces up to a 10-bit resolution PWM output and may have up to four outputs, depending on the selected operating mode. These outputs, designated P1A through P1D, are multiplexed with I/O pins on PORTC. The pin assignments are summarized in Table 11-3. FIGURE 11-3: To configure I/O pins as PWM outputs, the proper PWM mode must be selected by setting the P1M<1:0> and CCP1M<3:0> bits (CCP1CON<7:6> and CCP1CON<3:0>, respectively). The appropriate TRISC bits must also be set as outputs. SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODULE CCP1CON<5:4> Duty Cycle Registers CCP1M<3:0> 4 P1M<1:0> 2 CCPR1L CCP1/P1A RC5/CCP1/P1A TRISC<5> CCPR1H (Slave) P1B R Comparator TRISC<4> Output Controller Q RC4/C2OUT/P1B RC3/AN7/P1C P1C (1) TMR2 TRISC<3> S P1D Comparator Clear Timer2, toggle PWM pin and latch duty cycle PR2 Note 1: 11.3.1 TRISC<2> PWM1CON The 8-bit timer TMR2 register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler to create the 10-bit time base. PWM OUTPUT CONFIGURATIONS The P1M<1:0> bits in the CCP1CON register allows one of four configurations: • • • • RC2/AN6/P1D The general relationship of the outputs in all configurations is summarized in Figure 11-3. Note: Single Output Half-bridge Output Full-bridge Output, Forward mode Full-bridge Output, Reverse mode TABLE 11-3: Clearing the CCP1CON register will force the PWM output latches to their default inactive levels. This is not the PORTC I/O data latch. PIN ASSIGNMENTS FOR VARIOUS ENHANCED CCP MODES ECCP Mode CCP1CON Configuration RC5 RC4 RC3 RC2 Compatible CCP 00xx11xx CCP1 RC4/C2OUT RC3/AN7 RC2/AN6 Dual PWM 10xx11xx P1A P1B RC3/AN7 RC2/AN6 Quad PWM x1xx11xx P1A P1B P1C P1D Legend: x = Don’t care. Shaded cells indicate pin assignments not used by ECCP in a given mode. Note 1: TRIS register values must be configured appropriately. 2: With ECCP in Dual or Quad PWM mode, the C2OUT output control of PORTC must be disabled. DS41202C-page 78 Preliminary 2004 Microchip Technology Inc. PIC16F684 11.3.2 PWM PERIOD A PWM output (Figure 11-4 and Figure 11-5) has a time base (period) and a time that the output is active (duty cycle). The PWM period is specified by writing to the PR2 register. The PWM period can be calculated using the following formula: The following equation is used to calculate the PWM duty cycle in time: EQUATION 11-2: PWM duty cycle = ( CCPR1L:CCP1CON<5:4> ) • T OSC • (TMR2 prescale value) EQUATION 11-1: When the CCPR1H and 2-bit latch match TMR2, concatenated with an internal 2-bit Q clock or 2 bits of the TMR2 prescaler, the appropriate PWM pin is toggled. In Dual PWM mode, the pin will be toggled after the dead band time has expired. PWM period = [ ( PR2 ) + 1 ] • 4 • T OSC • (TMR2 prescale value) PWM frequency is defined as 1 / [PWM period]. When TMR2 is equal to PR2, the following three events occur on the next increment cycle: • TMR2 is cleared • The appropriate PWM pin toggles. In Dual PWM mode, this occurs after the dead band delay expires (exception: if PWM duty cycle = 0%, the pin will not be set) • The PWM duty cycle is latched from CCPR1L into CCPR1H Note: 11.3.3 The maximum PWM resolution for a given PWM frequency is given by the formula: EQUATION 11-3: The Timer2 postscaler (see Section 7.1 “Timer2 Operation”) is not used in the determination of the PWM frequency. The postscaler could be used to have a servo update rate at a different frequency than the PWM output. PWM DUTY CYCLE The PWM duty cycle is specified by writing to the CCPR1L register and to the DC1B<1:0> (CCP1CON<5:4>) bits. Up to 10 bits of resolution is available. The CCPR1L contains the eight MSbs and the DC1B<1:0> contains the two LSbs. CCPR1L and DC1B<1:0> can be written to at any time. In PWM mode, CCPR1H is a read-only register. This 10-bit value is represented by CCPR1L (CCP1CON<5:4>). TABLE 11-4: F OSC log ------------------------------------------------------------- F PWM • TMR2 Prescaler Resolution = --------------------------------------------------------------------------- bits log ( 2 ) All control registers are double buffered and are loaded at the beginning of a new PWM cycle (the period boundary when Timer2 resets) in order to prevent glitches on any of the outputs. The exception is the PWM delay register, which is loaded at either the duty cycle boundary or the period boundary (whichever comes first). Because of the buffering, the module waits until the timer resets, instead of starting immediately. This means that enhanced PWM waveforms do not exactly match the standard PWM waveforms, but are instead offset by one full instruction cycle (4 TOSC). Note: If the PWM duty cycle value is longer than the PWM period, the assigned PWM pin(s) will remain unchanged. EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz) PWM Frequency Timer Prescale (1, 4, 16) PR2 Value Maximum Resolution (bits) Note 1: The polarity (active-high or active-low) and mode of the signal are configured by the P1M<1:0> (CCP1CON<7:6>) and CCP1M<3:0> (CCP1CON<3:0>) bits. 1.22 kHz(1) 4.88 kHz(1) 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz 16 4 1 1 1 1 0xFF 0xFF 0xFF 0x3F 0x1F 0x17 10 10 10 8 7 6.6 Changing duty cycle will cause a glitch. 2004 Microchip Technology Inc. Preliminary DS41202C-page 79 PIC16F684 FIGURE 11-4: PWM OUTPUT RELATIONSHIPS (ACTIVE-HIGH STATE) 0 PR2+1 Duty Cycle SIGNAL CCP1CON <7:6> Period 00 (SINGLE OUTPUT) P1A MODULATED Delay(1) Delay(1) P1A MODULATED (Half-bridge) 10 P1B MODULATED P1A ACTIVE (Full-bridge, Forward) 01 P1B INACTIVE P1C INACTIVE P1D MODULATED P1A INACTIVE (Full-bridge, Reverse) 11 P1B MODULATED P1C ACTIVE P1D INACTIVE Relationships: • Period = 4 * TOSC * (PR2 + 1) * (TMR2 prescale value) • Duty Cycle = TOSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 prescale value) • Delay = 4 * TOSC * (PWM1CON<6:0>) Note 1: Dead band delay is programmed using the PWM1CON register (Section 11.3.6 “Programmable Dead Band Delay”). FIGURE 11-5: PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE) 0 CCP1CON <7:6> SIGNAL 00 (SINGLE OUTPUT) P1A MODULATED Period P1A MODULATED 10 (Half-bridge) PR2+1 Duty Cycle Delay(1) Delay(1) P1B MODULATED P1A ACTIVE 01 (Full-bridge, Forward) P1B INACTIVE P1C INACTIVE P1D MODULATED P1A INACTIVE 11 (Full-bridge, Reverse) P1B MODULATED P1C ACTIVE P1D INACTIVE Relationships: • Period = 4 * TOSC * (PR2 + 1) * (TMR2 prescale value) • Duty Cycle = TOSC * (CCPR1L<7:0>:CCP1CON<5:4>) * (TMR2 prescale value) • Delay = 4 * TOSC * (PWM1CON<6:0>) Note 1: DS41202C-page 80 Dead band delay is programmed using the PWM1CON register (Section 11.3.6 “Programmable Dead Band Delay”). Preliminary 2004 Microchip Technology Inc. PIC16F684 11.3.4 HALF-BRIDGE MODE In the Half-bridge Output mode, two pins are used as outputs to drive push-pull loads. The PWM output signal is output on the RC5/CCP1/P1A pin, while the complementary PWM output signal is output on the RC4/C2OUT/P1B pin (Figure 11-6). This mode can be used for half-bridge applications, as shown in Figure 11-7, or for full-bridge applications, where four power switches are being modulated with two PWM signals. In Half-bridge Output mode, the programmable dead band delay can be used to prevent shoot-through current in half-bridge power devices. The value of bits PDC<6:0> (PWM1CON<6:0>) sets the number of instruction cycles before the output is driven active. If the value is greater than the duty cycle, the corresponding output remains inactive during the entire cycle. See Section 11.3.6 “Programmable Dead Band Delay” for more details of the dead band delay operations. Since the P1A and P1B outputs are multiplexed with the PORTC<5:4> data latches, the TRISC<5:4> bits must be cleared to configure P1A and P1B as outputs. FIGURE 11-6: Period Period Duty Cycle P1A(2) td td P1B(2) (1) (1) (1) td = Dead Band Delay Note 1: 2: FIGURE 11-7: HALF-BRIDGE PWM OUTPUT At this time, the TMR2 register is equal to the PR2 register. Output signals are shown as active-high. EXAMPLES OF HALF-BRIDGE APPLICATIONS V+ Standard Half-bridge Circuit (“Push-Pull”) FET Driver + V - P1A PIC16F684 Load FET Driver + V - P1B V- Half-bridge Output Driving a Full-bridge Circuit V+ FET Driver FET Driver P1A PIC16F684 FET Driver Load FET Driver P1B V- 2004 Microchip Technology Inc. Preliminary DS41202C-page 81 PIC16F684 11.3.5 FULL-BRIDGE MODE In Full-bridge Output mode, four pins are used as outputs; however, only two outputs are active at a time. In the Forward mode, pin RC5/CCP1/P1A is continuously active and pin RC2/AN6/P1D is modulated. FIGURE 11-8: In the Reverse mode, RC3/AN7/P1C pin is continuously active and RC4/C2OUT/P1B pin is modulated. These are illustrated in Figure 11-8. P1A, P1B, P1C and P1D outputs are multiplexed with the PORTC<5:2> data latches. The TRISC<5:2> bits must be cleared to make the P1A, P1B, P1C and P1D pins output. FULL-BRIDGE PWM OUTPUT FORWARD MODE Period P1A (2) Duty Cycle P1B(2) P1C(2) P1D(2) (1) (1) REVERSE MODE Period Duty Cycle P1A(2) P1B(2) P1C(2) P1D(2) (1) Note 1: 2: (1) At this time, the TMR2 register is equal to the PR2 register. Output signal is shown as active-high. DS41202C-page 82 Preliminary 2004 Microchip Technology Inc. PIC16F684 FIGURE 11-9: EXAMPLE OF FULL-BRIDGE APPLICATION V+ FET Driver QC QA FET Driver P1A Load P1B PIC16F684 FET Driver P1C FET Driver QD QB VP1D 11.3.5.1 Direction Change in Full-Bridge Mode In the Full-bridge Output mode, the P1M1 bit (CCP1CON<7>) allows user to control the Forward/Reverse direction. When the application firmware changes this direction control bit, the module will assume the new direction on the next PWM cycle. Just before the end of the current PWM period, the modulated outputs (P1B and P1D) are placed in their inactive state, while the unmodulated outputs (P1A and P1C) are switched to drive in the opposite direction. This occurs in a time interval of (4 TOSC*(Timer2 Prescale value)) before the next PWM period begins. The Timer2 prescaler will be either 1, 4 or 16, depending on the value of the T2CKPS<1:0> bits (T2CON<1:0>). During the interval from the switch of the unmodulated outputs to the beginning of the next period, the modulated outputs (P1B and P1D) remain inactive. This relationship is shown in Figure 11-10. Figure 11-11 shows an example where the PWM direction changes from forward to reverse, at a near 100% duty cycle. At time t1, the output P1A and P1D become inactive, while output P1C becomes active. In this example, since the turn off time of the power devices is longer than the turn on time, a shoot-through current may flow through power devices QC and QD (see Figure 11-9) for the duration of ‘t’. The same phenomenon will occur to power devices QA and QB for PWM direction change from reverse to forward. If changing PWM direction at high duty cycle is required for an application, one of the following requirements must be met: 1. 2. Reduce PWM duty cycle for one PWM period before changing directions. Use switch drivers that can drive the switches off faster than they can drive them on. Other options to prevent shoot-through current may exist. Note that in the Full-bridge Output mode, the ECCP module does not provide any dead band delay. In general, since only one output is modulated at all times, dead band delay is not required. However, there is a situation where a dead band delay might be required. This situation occurs when both of the following conditions are true: 1. 2. The direction of the PWM output changes when the duty cycle of the output is at or near 100%. The turn off time of the power switch, including the power device and driver circuit, is greater than the turn on time. 2004 Microchip Technology Inc. Preliminary DS41202C-page 83 PIC16F684 FIGURE 11-10: PWM DIRECTION CHANGE Period(1) SIGNAL Period P1A (Active-High) P1B (Active-High) DC P1C (Active-High) (2) P1D (Active-High) DC Note 1: 2: The direction bit in the ECCP Control register (CCP1CON<7>) is written any time during the PWM cycle. When changing directions, the P1A and P1C signals switch before the end of the current PWM cycle at intervals of 4 TOSC, 16 TOSC or 64 TOSC, depending on the Timer2 prescaler value. The modulated P1B and P1D signals are inactive at this time. FIGURE 11-11: PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE Forward Period t1 Reverse Period P1A P1B DC P1C P1D DC TON External Switch C TOFF External Switch D Potential Shoot-Through Current T = TOFF - TON Note 1:All signals are shown as active-high. 2: TON is the turn on delay of power switch QC and its driver. 3: TOFF is the turn off delay of power switch QD and its driver. DS41202C-page 84 Preliminary 2004 Microchip Technology Inc. PIC16F684 11.3.6 PROGRAMMABLE DEAD BAND DELAY 11.3.7 In half-bridge applications where all power switches are modulated at the PWM frequency at all times, the power switches normally require more time to turn off than to turn on. If both the upper and lower power switches are switched at the same time (one turned on, and the other turned off), both switches may be on for a short period of time until one switch completely turns off. During this brief interval, a very high current (shoot-through current) may flow through both power switches, shorting the bridge supply. To avoid this potentially destructive shoot-through current from flowing during switching, turning on either of the power switches is normally delayed to allow the other switch to completely turn off. In the Half-bridge Output mode, a digitally programmable dead band delay is available to avoid shoot-through current from destroying the bridge power switches. The delay occurs at the signal transition from the non-active state to the active state. See Figure 11-6 for illustration. The lower seven bits of the PWM1CON register (Register 11-2) sets the delay period in terms of microcontroller instruction cycles (TCY or 4 TOSC). ENHANCED PWM AUTO-SHUTDOWN When the ECCP is programmed for any of the enhanced PWM modes, the active output pins may be configured for auto-shutdown. Auto-shutdown immediately places the enhanced PWM output pins into a defined shutdown state when a shutdown event occurs. A shutdown event can be caused by either of the two comparators or the INT pin (or any combination of these three sources). The comparators may be used to monitor a voltage input proportional to a current being monitored in the bridge circuit. If the voltage exceeds a threshold, the comparator switches state and triggers a shutdown. Alternatively, a digital signal on the INT pin can also trigger a shutdown. The auto-shutdown feature can be disabled by not selecting any auto-shutdown sources. The auto-shutdown sources to be used are selected using the ECCPAS<2:0> bits (ECCPAS<6:4>). When a shutdown occurs, the output pins are asynchronously placed in their shutdown states, specified by the PSSAC<1:0> and PSSBD<1:0> bits (ECCPAS<3:0>). Each pin pair (P1A/P1C and P1B/P1D) may be set to drive high, drive low, or be tri-stated (not driving). The ECCPASE bit (ECCPAS<7>) is also set to hold the enhanced PWM outputs in their shutdown states. The ECCPASE bit is set by hardware when a shutdown event occurs. If Auto-restarts are not enabled, the ECCPASE bit is cleared by firmware when the cause of the shutdown clears. If Auto-restarts are enabled, the ECCPASE bit is automatically cleared when the cause of the auto-shutdown has cleared. See Section 11.3.7.1 “Auto-shutdown and Auto-restart” for more information. REGISTER 11-2: PWM1CON – PWM CONFIGURATION REGISTER (ADDRESS: 16h) R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 PRSEN PDC6 PDC5 PDC4 PDC3 PDC2 PDC1 PDC0 bit 7 bit 0 bit 7 PRSEN: PWM Restart Enable bit 1 = Upon auto-shutdown, the ECCPASE bit clears automatically once the shutdown event goes away; the PWM restarts automatically. 0 = Upon auto-shutdown, ECCPASE must be cleared in software to restart the PWM. bit 6-0 PDC<6:0>: PWM Delay Count bits Number of FOSC/4 (4*TOSC) cycles between the scheduled time when a PWM signal should transition active, and the actual time it transitions active. Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 85 PIC16F684 REGISTER 11-3: ECCPAS – ENHANCED CAPTURE/COMPARE/PWM AUTO-SHUTDOWN CONTROL REGISTER (ADDRESS: 17h) R/W-0 R/W-0 R/W-0 R/W-0 ECCPASE ECCPAS2 ECCPAS1 ECCPAS0 R/W-0 R/W-0 R/W-0 R/W-0 PSSAC1 PSSAC0 PSSBD1 PSSBD0 bit 7 bit 0 bit 7 ECCPASE: ECCP Auto-shutdown Event Status bit 1 = A shutdown event has occurred; ECCP outputs are in shutdown state 0 = ECCP outputs are operating bit 6-4 ECCPAS<2:0>: ECCP Auto-shutdown Source Select bits 000 = Auto-shutdown is disabled 001 = Comparator 1 output change 010 = Comparator 2 output change 011 = Either Comparator 1 or 2 change 100 = VIL on INT pin 101 = VIL on INT pin or Comparator 1 change 110 = VIL on INT pin or Comparator 2 change 111 = VIL on INT pin or Comparator 1 or Comparator 2 change bit 3-2 PSSACn: Pin A and C Shutdown State Control bits 00 = Drive Pins A and C to ‘0’ 01 = Drive Pins A and C to ‘1’ 1x = Pins A and C tri-state bit 1-0 PSSBDn: Pin B and D Shutdown State Control bits 00 = Drive Pins B and D to ‘0’ 01 = Drive Pins B and D to ‘1’ 1x = Pins B and D tri-state Legend: DS41202C-page 86 R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 11.3.7.1 Auto-shutdown and Auto-restart 11.3.8 The auto-shutdown feature can be configured to allow auto-restarts of the module following a shutdown event. This is enabled by setting the PRSEN bit of the PWM1CON register (PWM1CON<7>). In Shutdown mode with PRSEN = 1 (Figure 11-12), the ECCPASE bit will remain set for as long as the cause of the shutdown continues. When the shutdown condition clears, the ECCPASE bit is cleared. If PRSEN = 0 (Figure 11-13), once a shutdown condition occurs, the ECCPASE bit will remain set until it is cleared by firmware. Once ECCPASE is cleared, the enhanced PWM will resume at the beginning of the next PWM period. Note: Writing to the ECCPASE bit is disabled while a shutdown condition is active. Independent of the PRSEN bit setting, whether the auto-shutdown source is one of the comparators or INT, the shutdown condition is a level. The ECCPASE bit cannot be cleared as long as the cause of the shutdown persists. The Auto-shutdown mode can be forced by writing a ‘1’ to the ECCPASE bit. FIGURE 11-12: START-UP CONSIDERATIONS When the ECCP module is used in the PWM mode, the application hardware must use the proper external pull-up and/or pull-down resistors on the PWM output pins. When the microcontroller is released from Reset, all of the I/O pins are in the high-impedance state. The external circuits must keep the power switch devices in the off state, until the microcontroller drives the I/O pins with the proper signal levels, or activates the PWM output(s). The CCP1M<1:0> bits (CCP1CON<1:0>) allow the user to choose whether the PWM output signals are active-high or active-low for each pair of PWM output pins (P1A/P1C and P1B/P1D). The PWM output polarities must be selected before the PWM pins are configured as outputs. Changing the polarity configuration while the PWM pins are configured as outputs is not recommended since it may result in damage to the application circuits. The P1A, P1B, P1C and P1D output latches may not be in the proper states when the PWM module is initialized. Enabling the PWM pins for output at the same time as the ECCP module may cause damage to the application circuit. The ECCP module must be enabled in the proper Output mode and complete a full PWM cycle before configuring the PWM pins as outputs. The completion of a full PWM cycle is indicated by the TMR2IF bit being set as the second PWM period begins. PWM AUTO-SHUTDOWN (PRSEN = 1, AUTO-RESTART ENABLED) PWM Period Shutdown Event ECCPASE bit PWM Activity Normal PWM Start of PWM Period FIGURE 11-13: Shutdown Shutdown Event Occurs Event Clears PWM Resumes PWM AUTO-SHUTDOWN (PRSEN = 0, AUTO-RESTART DISABLED) PWM Period Shutdown Event ECCPASE bit PWM Activity Normal PWM Start of PWM Period 2004 Microchip Technology Inc. ECCPASE Cleared by Shutdown Shutdown Firmware PWM Event Occurs Event Clears Resumes Preliminary DS41202C-page 87 PIC16F684 11.3.9 OPERATION IN SLEEP MODE 11.3.11 SETUP FOR PWM OPERATION In Sleep mode, all clock sources are disabled. Timer2 will not increment, and the state of the module will not change. If the ECCP pin is driving a value, it will continue to drive that value. When the device wakes up, it will continue from this state. The following steps should be taken when configuring the ECCP module for PWM operation: 11.3.9.1 2. 3. OPERATION WITH FAIL-SAFE CLOCK MONITOR 1. If the Fail-Safe Clock Monitor is enabled, a clock failure will force the ECCP to be clocked from the internal oscillator clock source, which may have a different clock frequency than the primary clock. See Section 3.0 “Clock Sources” for additional details. 11.3.10 4. EFFECTS OF A RESET Any Reset will force all ports to Input mode and the ECCP registers to their Reset states. This forces the Enhanced CCP module to reset to a state compatible with the standard CCP module. 5. 6. 7. 8. 9. DS41202C-page 88 Preliminary Configure the PWM pins P1A and P1B (and P1C and P1D, if used) as inputs by setting the corresponding TRISC bits. Set the PWM period by loading the PR2 register. Configure the ECCP module for the desired PWM mode and configuration by loading the CCP1CON register with the appropriate values: • Select one of the available output configurations and direction with the P1M<1:0> bits. • Select the polarities of the PWM output signals with the CCP1M<3:0> bits. Set the PWM duty cycle by loading the CCPR1L register and CCP1CON<5:4> bits. For Half-bridge Output mode, set the dead band delay by loading PWM1CON<6:0> with the appropriate value. If auto-shutdown operation is required, load the ECCPAS register: • Select the auto-shutdown sources using the ECCPAS<2:0> bits. • Select the shutdown states of the PWM output pins using PSSAC<1:0> and PSSBD<1:0> bits. • Set the ECCPASE bit (ECCPAS<7>). • Configure the comparators using the CMCON0 register (Register 8-1). • Configure the comparator inputs as analog inputs. If auto-restart operation is required, set the PRSEN bit (PWM1CON<7>). Configure and start TMR2: • Clear the TMR2 interrupt flag bit by clearing the TMR2IF bit (PIR1<1>). • Set the TMR2 prescale value by loading the T2CKPS bits (T2CON<1:0>). • Enable Timer2 by setting the TMR2ON bit (T2CON<2>). Enable PWM outputs after a new PWM cycle has started: • Wait until TMR2 overflows (TMR2IF bit is set). • Enable the CCP1/P1A, P1B, P1C and/or P1D pin outputs by clearing the respective TRISC bits. • Clear the ECCPASE bit (ECCPAS<7>). 2004 Microchip Technology Inc. PIC16F684 TABLE 11-5: REGISTERS ASSOCIATED WITH PWM AND TIMER2 Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOD Value on all other Resets 0Bh/ 8Bh INTCON GIE PEIE T0IE INTE RAIE T0IF INTF RAIF 0000 0000 0000 0000 0Ch PIR1 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF TMR1IF 0000 0000 0000 0000 11h TMR2 12h T2CON 13h CCPR1L 14h CCPR1H 15h CCP1CON P1M1 P1M0 DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 16h PWM1CON PRSEN PDC6 PDC5 PDC4 PDC3 PDC2 17h ECCPAS ECCPASE ECCPAS2 ECCPAS1 ECCPAS0 PSSAC1 87h TRISC — — TRISC5 TRISC4 TRISC3 8Ch PIE1 EEIE ADIE CCP1IE C2IE C1IE 92h PR2 Addr Legend: Timer2 Module register 0000 0000 0000 0000 -000 0000 -000 0000 Capture/Compare/PWM Register1 Low Byte xxxx xxxx uuuu uuuu Capture/Compare/PWM Register1 High Byte xxxx xxxx uuuu uuuu CCP1M0 0000 0000 0000 0000 PDC1 PDC0 0000 0000 0000 0000 PSSAC0 PSSBD1 PSSBD0 0000 0000 0000 0000 TRISC2 TRISC1 TRISC0 --11 1111 --11 1111 OSFIE TMR2IE TMR1IE 0000 0000 0000 0000 1111 1111 1111 1111 — TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON Timer2 Module Period register T2CKPS1 T2CKPS0 — = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown. Shaded cells are not used by the Capture, Compare or Timer1 module. 2004 Microchip Technology Inc. Preliminary DS41202C-page 89 PIC16F684 NOTES: DS41202C-page 90 Preliminary 2004 Microchip Technology Inc. PIC16F684 12.0 SPECIAL FEATURES OF THE CPU The PIC16F684 has a host of features intended to maximize system reliability, minimize cost through elimination of external components, provide power saving features and offer code protection. These features are: • Reset - Power-on Reset (POR) - Power-up Timer (PWRT) - Oscillator Start-up Timer (OST) - Brown-out Detect (BOD) • Interrupts • Watchdog Timer (WDT) • Oscillator selection • Sleep • Code protection • ID Locations • In-Circuit Serial Programming 2004 Microchip Technology Inc. The PIC16F684 has two timers that offer necessary delays on power-up. One is the Oscillator Start-up Timer (OST), intended to keep the chip in Reset until the crystal oscillator is stable. The other is the Power-up Timer (PWRT), which provides a fixed delay of 64 ms (nominal) on power-up only, designed to keep the part in Reset while the power supply stabilizes. There is also circuitry to reset the device if a brown-out occurs, which can use the Power-up Timer to provide at least a 64 ms Reset. With these three functions-on-chip, most applications need no external Reset circuitry. The Sleep mode is designed to offer a very low -current Power-down mode. The user can wake-up from Sleep through: • External Reset • Watchdog Timer Wake-up • An interrupt Several oscillator options are also made available to allow the part to fit the application. The INTOSC option saves system cost while the LP crystal option saves power. A set of configuration bits are used to select various options (see Register 12-1). Preliminary DS41202C-page 91 PIC16F684 12.1 Configuration Bits Note: The configuration bits can be programmed (read as ‘0’), or left unprogrammed (read as ‘1’) to select various device configurations as shown in Register 12-1. These bits are mapped in program memory location 2007h. REGISTER 12-1: — — Address 2007h is beyond the user program memory space. It belongs to the special configuration memory space (2000h3FFFh), which can be accessed only during programming. See “PIC12F6XX/16F6XX Memory Programming Specification” (DS41204) for more information. CONFIG – CONFIGURATION WORD (ADDRESS: 2007h) FCMEN IESO BODEN1 BODEN0 CPD CP MCLRE PWRTE WDTE FOSC2 FOSC1 FOSC0 bit 13 bit 0 bit 13-12 Unimplemented: Read as ‘1’ bit 11 FCMEN: Fail-Safe Clock Monitor Enabled bit 1 = Fail-Safe Clock Monitor is enabled 0 = Fail-Safe Clock Monitor is disabled bit 10 IESO: Internal External Switchover bit 1 = Internal External Switchover mode is enabled 0 = Internal External Switchover mode is disabled bit 9-8 BODEN<1:0>: Brown-out Detect Selection bits(1) 11 = BOD enabled 10 = BOD enabled during operation and disabled in Sleep 01 = BOD controlled by SBODEN bit (PCON<4>) 00 = BOD disabled bit 7 CPD: Data Code Protection bit(2) 1 = Data memory code protection is disabled 0 = Data memory code protection is enabled bit 6 CP: Code Protection bit(3) 1 = Program memory code protection is disabled 0 = Program memory code protection is enabled bit 5 MCLRE: RA3/MCLR pin function select bit(4) 1 = RA3/MCLR pin function is MCLR 0 = RA3/MCLR pin function is digital input, MCLR internally tied to VDD bit 4 PWRTE: Power-up Timer Enable bit 1 = PWRT disabled 0 = PWRT enabled bit 3 WDTE: Watchdog Timer Enable bit 1 = WDT enabled 0 = WDT disabled and can be enabled by SWDTEN bit (WDTCON<0>) bit 2-0 FOSC<2:0>: Oscillator Selection bits 111 = RC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, RC on RA5/OSC1/CLKIN 110 = RCIO oscillator: I/O function on RA4/OSC2/CLKOUT pin, RC on RA5/OSC1/CLKIN 101 = INTOSC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN 100 = INTOSCIO oscillator: I/O function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN 011 = EC: I/O function on RA4/OSC2/CLKOUT pin, CLKIN on RA5/OSC1/CLKIN 010 = HS oscillator: High-speed crystal/resonator on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN 001 = XT oscillator: Crystal/resonator on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN 000 = LP oscillator: Low-power crystal on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN Note 1: Enabling Brown-out Detect does not automatically enable Power-up Timer. 2: The entire data EEPROM will be erased when the code protection is turned off. 3: The entire program memory will be erased when the code protection is turned off. 4: When MCLR is asserted in INTOSC or RC mode, the internal clock oscillator is disabled. Legend: R = Readable W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared DS41202C-page 92 Preliminary x = Bit is unknown 2004 Microchip Technology Inc. PIC16F684 12.2 Calibration Bits The Brown-out Detect (BOD), Power-on Reset (POR) and 8 MHz internal oscillator (HFINTOSC) are factory calibrated. These calibration values are stored in the Calibration Word register, as shown in Register 12-2 and are mapped in program memory location 2008h. Note: The Calibration Word register is not erased when the device is erased when using the procedure described in the “PIC12F6XX/16F6XX Memory Programming Specification” (DS41204). Therefore, it is not necessary to store and reprogram these values when the device is erased. REGISTER 12-2: — Address 2008h is beyond the user program memory space. It belongs to the special configuration memory space (2000h3FFFh), which can be accessed only during programming. See “PIC12F6XX/16F6XX Memory Programming Specification” (DS41204) for more information. CALIB – CALIBRATION WORD (ADDRESS: 2008h) FCAL6 FCAL5 FCAL4 FCAL3 FCAL2 FCAL1 FCAL0 — POR1 POR0 BOD2 BOD1 bit 13 BOD0 bit 0 bit 13 Unimplemented: Read as ‘0’ bit 12-6 FCAL<6:0>: Internal Oscillator Calibration bits 0111111 = Maximum frequency . . 0000001 0000000 = Center frequency 1111111 . . 1000000 = Minimum frequency bit 5 Unimplemented: Read as ‘0’ bit 4-3 POR<1:0>: POR Calibration bits 00 = Lowest POR voltage 11 = Highest POR voltage bit 2-0 BOD<2:0>: BOD Calibration bits 000 = Reserved 001 = Lowest BOD voltage 111 = Highest BOD voltage Legend: R = Readable W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared 2004 Microchip Technology Inc. Preliminary x = Bit is unknown DS41202C-page 93 PIC16F684 12.3 Reset The PIC16F684 differentiates between various kinds of Reset: a) b) c) d) e) f) Power-on Reset (POR) WDT Reset during normal operation WDT Reset during Sleep MCLR Reset during normal operation MCLR Reset during Sleep Brown-out Detect (BOD) A simplified block diagram of the On-Chip Reset Circuit is shown in Figure 12-1. Some registers are not affected in any Reset condition; their status is unknown on POR and unchanged in any other Reset. Most other registers are reset to a “Reset state” on: • • • • • They are not affected by a WDT wake-up since this is viewed as the resumption of normal operation. TO and PD bits are set or cleared differently in different Reset situations, as indicated in Table 12-2. These bits are used in software to determine the nature of the Reset. See Table 12-4 for a full description of Reset states of all registers. The MCLR Reset path has a noise filter to detect and ignore small pulses. See Section 15.0 “Electrical Specifications” for pulse-width specifications. Power-on Reset MCLR Reset MCLR Reset during Sleep WDT Reset Brown-out Detect (BOD) FIGURE 12-1: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT External Reset MCLR/VPP pin SLEEP WDT Module WDT Time-out Reset VDD Rise Detect Power-on Reset VDD Brown-out(1) Detect BODEN SBODEN S OST/PWRT OST Chip_Reset 10-bit Ripple Counter R Q OSC1/ CLKI pin PWRT LFINTOSC 11-bit Ripple Counter Enable PWRT Enable OST Note 1: Refer to the Configuration Word register (Register 12-1). DS41202C-page 94 Preliminary 2004 Microchip Technology Inc. PIC16F684 12.3.1 POWER-ON RESET FIGURE 12-2: The on-chip POR circuit holds the chip in Reset until VDD has reached a high enough level for proper operation. To take advantage of the POR, simply connect the MCLR pin through a resistor to VDD. This will eliminate external RC components usually needed to create Power-on Reset. A maximum rise time for VDD is required. See Section 15.0 “Electrical Specifications” for details. If the BOD is enabled, the maximum rise time specification does not apply. The BOD circuitry will keep the device in Reset until VDD reaches VBOD (see Section 12.3.5 “Brown-Out Detect (BOD)”). Note: The POR circuit does not produce an internal Reset when VDD declines. To re-enable the POR, VDD must reach Vss for a minimum of 100 µs. When the device starts normal operation (exits the Reset condition), device operating parameters (i.e., voltage, frequency, temperature, etc.) must be met to ensure operation. If these conditions are not met, the device must be held in Reset until the operating conditions are met. For additional information, refer to Application Note AN607, “Power-up Trouble Shooting” (DS00607). 12.3.2 MCLR PIC16F684 has a noise filter in the MCLR Reset path. The filter will detect and ignore small pulses. VDD PIC16F684 R1 1 kΩ (or greater) MCLR C1 0.1 µF (optional, not critical) 12.3.3 POWER-ON RESET (POR) The on-chip POR circuit holds the chip in Reset until VDD has reached a high enough level for proper operation. To take advantage of the POR, simply connect the MCLR pin through a resistor to VDD. This will eliminate external RC components usually needed to create Power-on Reset. A maximum rise time for VDD is required. See Section 15.0 “Electrical Specifications” for details. If the BOD is enabled, the maximum rise time specification does not apply. The BOD circuitry will keep the device in Reset until VDD reaches VBOD (see Section 12.3.5 “Brown-Out Detect (BOD)”). Note: It should be noted that a WDT Reset does not drive MCLR pin low. The behavior of the ESD protection on the MCLR pin has been altered from early devices of this family. Voltages applied to the pin that exceed its specification can result in both MCLR Resets and excessive current beyond the device specification during the ESD event. For this reason, Microchip recommends that the MCLR pin no longer be tied directly to VDD. The use of an RC network, as shown in Figure 12-2, is suggested. RECOMMENDED MCLR CIRCUIT The POR circuit does not produce an internal Reset when VDD declines. To re-enable the POR, VDD must reach Vss for a minimum of 100 µs. When the device starts normal operation (exits the Reset condition), device operating parameters (i.e., voltage, frequency, temperature, etc.) must be met to ensure operation. If these conditions are not met, the device must be held in Reset until the operating conditions are met. For additional information, refer to Application Note AN607, “Power-up Trouble Shooting” (DS00607). An internal MCLR option is enabled by clearing the MCLRE bit in the Configuration Word register. When cleared, MCLR is internally tied to VDD and an internal weak pull-up is enabled for the MCLR pin. In-Circuit Serial Programming is not affected by selecting the internal MCLR option. 2004 Microchip Technology Inc. Preliminary DS41202C-page 95 PIC16F684 12.3.4 POWER-UP TIMER (PWRT) If VDD falls below VBOD for greater than parameter (TBOD) (see Section 15.0 “Electrical Specifications”), the Brown-out situation will reset the device. This will occur regardless of VDD slew rate. A Reset is not insured to occur if VDD falls below VBOD for less than parameter (TBOD). The Power-up Timer provides a fixed 64 ms (nominal) time-out on power-up only, from POR or Brown-out Detect. The Power-up Timer operates from the 31 kHz LFINTOSC oscillator. For more information, see Section 3.4 “Internal Clock Modes”. The chip is kept in Reset as long as PWRT is active. The PWRT delay allows the VDD to rise to an acceptable level. A configuration bit, PWRTE, can disable (if set) or enable (if cleared or programmed) the Power-up Timer. The Power-up Timer should be enabled when Brown-out Detect is enabled, although it is not required. On any Reset (Power-on, Brown-out Detect, Watchdog timer, etc.), the chip will remain in Reset until VDD rises above VBOD (see Figure 12-3). The Power-up Timer will now be invoked, if enabled and will keep the chip in Reset an additional 64 ms. Note: The Power-up Timer delay will vary from chip-to-chip and vary due to: • VDD variation • Temperature variation • Process variation See DC parameters for details “Electrical Specifications”). 12.3.5 If VDD drops below VBOD while the Power-up Timer is running, the chip will go back into a Brown-out Detect and the Power-up Timer will be re-initialized. Once VDD rises above VBOD, the Power-up Timer will execute a 64 ms Reset. (Section 15.0 12.3.6 BROWN-OUT DETECT (BOD) Note: Address 2008h is beyond the user program memory space. It belongs to the special configuration memory space (2000h3FFFh), which can be accessed only during programming. See “PIC12F6XX/16F6XX Memory Programming Specification” (DS41204) for more information. BROWN-OUT SITUATIONS VDD Internal Reset VBOD 64 ms(1) VDD Internal Reset VBOD < 64 ms 64 ms(1) VDD VBOD Internal Reset Note 1: BOD CALIBRATION The PIC16F684 stores the BOD calibration values in fuses located in the Calibration Word register (2008h). The Calibration Word register is not erased when using the specified bulk erase sequence in the “PIC12F6XX/ 16F6XX Memory Programming Specification” (DS41204) and thus, does not require reprogramming. The BODEN0 and BODEN1 bits in the Configuration Word register select one of four BOD modes. Two modes have been added to allow software or hardware control of the BOD enable. When BODEN<1:0> = 01, the SBODEN bit (PCON<4>) enables/disables the BOD allowing it to be controlled in software. By selecting BODEN<1:0>, the BOD is automatically disabled in Sleep to conserve power and enabled on wake-up. In this mode, the SBODEN bit is disabled. See Register 12-1 for the configuration word definition. FIGURE 12-3: The Power-up Timer is enabled by the PWRTE bit in the Configuration Word register. 64 ms(1) 64 ms delay only if PWRTE bit is programmed to ‘0’. DS41202C-page 96 Preliminary 2004 Microchip Technology Inc. PIC16F684 12.3.7 TIME-OUT SEQUENCE 12.3.8 On power-up, the time-out sequence is as follows: first, PWRT time-out is invoked after POR has expired, then OST is activated after the PWRT time-out has expired. The total time-out will vary based on oscillator configuration and PWRTE bit status. For example, in EC mode with PWRTE bit erased (PWRT disabled), there will be no time-out at all. Figure 12-4, Figure 12-5 and Figure 12-6 depict time-out sequences. The device can execute code from the INTOSC while OST is active by enabling Two-Speed Start-up or Fail-Safe Monitor (see Section 3.6.2 “Two-Speed Start-up Sequence” and Section 3.7 “Fail-Safe Clock Monitor”). The Power Control register PCON (address 8Eh) has two status bits to indicate what type of Reset that last occurred. Bit 0 is BOD (Brown-out). BOD is unknown on Poweron Reset. It must then be set by the user and checked on subsequent Resets to see if BOD = 0, indicating that a Brown-out has occurred. The BOD Status bit is a “don’t care” and is not necessarily predictable if the brown-out circuit is disabled (BODEN<1:0> = 00 in the Configuration Word register). Bit 1 is POR (Power-on Reset). It is a ‘0’ on Power-on Reset and unaffected otherwise. The user must write a ‘1’ to this bit following a Power-on Reset. On a subsequent Reset, if POR is ‘0’, it will indicate that a Power-on Reset has occurred (i.e., VDD may have gone too low). Since the time-outs occur from the POR pulse, if MCLR is kept low long enough, the time-outs will expire. Then, bringing MCLR high will begin execution immediately (see Figure 12-5). This is useful for testing purposes or to synchronize more than one PIC16F684 device operating in parallel. For more information, see Section 4.2.3 “Ultra LowPower Wake-up” and Section 12.3.5 “Brown-Out Detect (BOD)”. Table 12-5 shows the Reset conditions for some special registers, while Table 12-4 shows the Reset conditions for all the registers. TABLE 12-1: POWER CONTROL (PCON) REGISTER TIME-OUT IN VARIOUS SITUATIONS Power-up Brown-out Detect PWRTE = 0 PWRTE = 1 PWRTE = 0 PWRTE = 1 Wake-up from Sleep TPWRT + 1024 • TOSC 1024 • TOSC TPWRT + 1024 • TOSC 1024 • TOSC 1024 • TOSC TPWRT — TPWRT — — Oscillator Configuration XT, HS, LP RC, EC, INTOSC TABLE 12-2: STATUS/PCON BITS AND THEIR SIGNIFICANCE POR BOD TO PD Condition 0 u 1 1 Power-on Reset 1 0 1 1 Brown-out Detect u u 0 u WDT Reset u u 0 0 WDT Wake-up u u u u MCLR Reset during normal operation u u 1 0 MCLR Reset during Sleep Legend: u = unchanged, x = unknown TABLE 12-3: Address SUMMARY OF REGISTERS ASSOCIATED WITH BROWN-OUT Name Bit 7 Bit 6 IRP RP1 — — Bit 5 Bit 4 Bit 3 Bit 2 RPO TO PD Z — — Bit 0 Value on POR, BOD Value on all other Resets(1) DC C 0001 1xxx 000q quuu POR BOD --01 --qq --0u --uu Bit 1 03h STATUS 8Eh PCON Legend: u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’, q = value depends on condition. Shaded cells are not used by BOD. Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation. Note 1: 2004 Microchip Technology Inc. ULPWUE SBODEN Preliminary DS41202C-page 97 PIC16F684 FIGURE 12-4: TIME-OUT SEQUENCE ON POWER-UP (DELAYED MCLR): CASE 1 VDD MCLR Internal POR TPWRT PWRT Time-out TOST OST Time-out Internal Reset TIME-OUT SEQUENCE ON POWER-UP (DELAYED MCLR): CASE 2 FIGURE 12-5: VDD MCLR Internal POR TPWRT PWRT Time-out TOST OST Time-out Internal Reset FIGURE 12-6: TIME-OUT SEQUENCE ON POWER-UP (MCLR WITH VDD) VDD MCLR Internal POR TPWRT PWRT Time-out TOST OST Time-out Internal Reset DS41202C-page 98 Preliminary 2004 Microchip Technology Inc. PIC16F684 TABLE 12-4: INITIALIZATION CONDITION FOR REGISTER Address Power-on Reset MCLR Reset WDT Reset Brown-out Detect(1) Wake-up from Sleep through Interrupt Wake-up from Sleep through WDT Time-out — xxxx xxxx uuuu uuuu uuuu uuuu INDF 00h/80h xxxx xxxx TMR0 01h xxxx xxxx uuuu uuuu uuuu uuuu 02h/82h 0000 0000 0000 0000 PC + 1(3) Register W PCL xxxx xxxx STATUS 03h/83h 0001 1xxx 000q quuu uuuq quuu(4) FSR 04h/84h xxxx xxxx uuuu uuuu uuuu uuuu 05h --xx xx00 --00 0000 --uu uuuu PORTC 07h --xx xx00 --00 0000 --uu uuuu PCLATH 0Ah/8Ah ---0 0000 ---0 0000 ---u uuuu INTCON 0Bh/8Bh 0000 0000 0000 0000 uuuu uuuu(2) PIR1 0Ch 0000 0000 0000 0000 uuuu uuuu(2) TMR1L 0Eh xxxx xxxx uuuu uuuu uuuu uuuu TMR1H 0Fh xxxx xxxx uuuu uuuu uuuu uuuu T1CON 10h 0000 0000 uuuu uuuu -uuu uuuu TMR2 11h 0000 0000 0000 0000 uuuu uuuu T2CON 12h -000 0000 -000 0000 -uuu uuuu CCPR1L 13h xxxx xxxx uuuu uuuu uuuu uuuu CCPR1H 14h xxxx xxxx uuuu uuuu uuuu uuuu CCP1CON 15h 0000 0000 0000 0000 uuuu uuuu PWM1CON 16h 0000 0000 0000 0000 uuuu uuuu ECCPAS 17h 0000 0000 0000 0000 uuuu uuuu WDTCON 18h ---0 1000 ---0 1000 ---u uuuu CMCON0 19h 0000 0000 0000 0000 uuuu uuuu CMCON1 1Ah ---- --10 ---- --10 ---- --uu ADRESH 1Eh xxxx xxxx uuuu uuuu uuuu uuuu ADCON0 1Fh 00-0 0000 00-0 0000 uu-u uuuu OPTION_REG 81h 1111 1111 1111 1111 uuuu uuuu TRISA 85h --11 1111 --11 1111 --uu uuuu TRISC 87h --11 1111 --11 1111 --uu uuuu PIE1 8Ch 0000 0000 0000 0000 uuuu uuuu PCON 8Eh --01 --0x --0u --uu(1, 5) --uu --uu OSCCON 8Fh -110 x000 -110 x000 -uuu uuuu OSCTUNE 90h ---0 0000 ---u uuuu ---u uuuu ANSEL 91h 1111 1111 1111 1111 uuuu uuuu PR2 92h 1111 1111 1111 1111 1111 1111 PORTA Legend: Note 1: 2: 3: 4: 5: (4) uuuu uuuu u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’, q = value depends on condition. If VDD goes too low, Power-on Reset will be activated and registers will be affected differently. One or more bits in INTCON and/or PIR1 will be affected (to cause wake-up). When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h). See Table 12-5 for Reset value for specific condition. If Reset was due to brown-out, then bit 0 = 0. All other Resets will cause bit 0 = u. 2004 Microchip Technology Inc. Preliminary DS41202C-page 99 PIC16F684 TABLE 12-4: INITIALIZATION CONDITION FOR REGISTER (CONTINUED) Address Power-on Reset MCLR Reset WDT Reset (Continued) Brown-out Detect(1) Wake-up from Sleep through Interrupt Wake-up from Sleep through WDT Time-out (Continued) WPUA 95h --11 -111 --11 -111 uuuu uuuu IOCA 96h --00 0000 --00 0000 --uu uuuu VRCON 99h 0-0- 0000 0-0- 0000 u-u- uuuu EEDAT 9Ah 0000 0000 0000 0000 uuuu uuuu EEADR 9Bh 0000 0000 0000 0000 uuuu uuuu EECON1 9Ch ---- x000 ---- q000 ---- uuuu EECON2 9Dh ---- ---- ---- ---- ---- ---- ADRESL 9Eh xxxx xxxx uuuu uuuu uuuu uuuu 9Fh -000 ---- -000 ---- -uuu ---- Register ADCON1 Legend: Note 1: 2: 3: 4: 5: u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’, q = value depends on condition. If VDD goes too low, Power-on Reset will be activated and registers will be affected differently. One or more bits in INTCON and/or PIR1 will be affected (to cause wake-up). When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h). See Table 12-5 for Reset value for specific condition. If Reset was due to brown-out, then bit 0 = 0. All other Resets will cause bit 0 = u. TABLE 12-5: INITIALIZATION CONDITION FOR SPECIAL REGISTERS Program Counter Status Register PCON Register Power-on Reset 000h 0001 1xxx --01 --0x MCLR Reset during normal operation 000h 000u uuuu --0u --uu MCLR Reset during Sleep 000h 0001 0uuu --0u --uu WDT Reset 000h 0000 uuuu --0u --uu PC + 1 uuu0 0uuu --uu --uu 000h 0001 1uuu --01 --10 uuu1 0uuu --uu --uu Condition WDT Wake-up Brown-out Detect Interrupt Wake-up from Sleep PC + 1 (1) Legend: u = unchanged, x = unknown, — = unimplemented bit, reads as ‘0’. Note 1: When the wake-up is due to an interrupt and Global Interrupt Enable bit, GIE, is set, the PC is loaded with the interrupt vector (0004h) after execution of PC + 1. DS41202C-page 100 Preliminary 2004 Microchip Technology Inc. PIC16F684 12.4 Interrupts For external interrupt events, such as the INT pin or PORTA change interrupt, the interrupt latency will be three or four instruction cycles. The exact latency depends upon when the interrupt event occurs (see Figure 12-8). The latency is the same for one or twocycle instructions. Once in the Interrupt Service Routine, the source(s) of the interrupt can be determined by polling the interrupt flag bits. The interrupt flag bit(s) must be cleared in software before re-enabling interrupts to avoid multiple interrupt requests. The PIC16F684 has 11 sources of interrupt: • • • • • • • • • • External Interrupt RA2/INT TMR0 Overflow Interrupt PORTA Change Interrupts 2 Comparator Interrupts A/D Interrupt Timer1 Overflow Interrupt Timer2 Match Interrupt EEPROM Data Write Interrupt Fail-Safe Clock Monitor Interrupt Enhanced CCP Interrupt Note 1: Individual interrupt flag bits are set, regardless of the status of their corresponding mask bit or the GIE bit. 2: When an instruction that clears the GIE bit is executed, any interrupts that were pending for execution in the next cycle are ignored. The interrupts, which were ignored, are still pending to be serviced when the GIE bit is set again. The Interrupt Control register (INTCON) and Peripheral Interrupt Request Register 1 (PIR1) record individual interrupt requests in flag bits. The INTCON register also has individual and global interrupt enable bits. A Global Interrupt Enable bit, GIE (INTCON<7>), enables (if set) all unmasked interrupts, or disables (if cleared) all interrupts. Individual interrupts can be disabled through their corresponding enable bits in the INTCON register and PIE1 register. GIE is cleared on Reset. The Return from Interrupt instruction, RETFIE, exits the interrupt routine, as well as sets the GIE bit, which re-enables unmasked interrupts. The following interrupt flags are contained in the INTCON register: • INT Pin Interrupt • PORTA Change Interrupt • TMR0 Overflow Interrupt The peripheral interrupt flags are contained in the special register, PIR1. The corresponding interrupt enable bit is contained in special register, PIE1. The following interrupt flags are contained in the PIR1 register: • • • • • • • EEPROM Data Write Interrupt A/D Interrupt 2 Comparator Interrupts Timer1 Overflow Interrupt Timer2 Match Interrupt Fail-Safe Clock Monitor Interrupt Enhanced CCP Interrupt For additional information on Timer1, Timer2, comparators, A/D, data EEPROM or Enhanced CCP modules, refer to the respective peripheral section. 12.4.1 RA2/INT INTERRUPT External interrupt on RA2/INT pin is edge-triggered; either rising if the INTEDG bit (Option<6>) is set, or falling, if the INTEDG bit is clear. When a valid edge appears on the RA2/INT pin, the INTF bit (INTCON<1>) is set. This interrupt can be disabled by clearing the INTE control bit (INTCON<4>). The INTF bit must be cleared in software in the Interrupt Service Routine before re-enabling this interrupt. The RA2/INT interrupt can wake-up the processor from Sleep, if the INTE bit was set prior to going into Sleep. The status of the GIE bit decides whether or not the processor branches to the interrupt vector following wake-up (0004h). See Section 12.7 “Power-Down Mode (Sleep)” for details on Sleep and Figure 12-10 for timing of wake-up from Sleep through RA2/INT interrupt. Note: The ANSEL (91h) and CMCON0 (19h) registers must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read ‘0’. When an interrupt is serviced: • The GIE is cleared to disable any further interrupt. • The return address is pushed onto the stack. • The PC is loaded with 0004h. 2004 Microchip Technology Inc. Preliminary DS41202C-page 101 PIC16F684 12.4.2 TMR0 INTERRUPT 12.4.3 An overflow (FFh → 00h) in the TMR0 register will set the T0IF (INTCON<2>) bit. The interrupt can be enabled/disabled by setting/clearing T0IE (INTCON<5>) bit. See Section 5.0 “Timer0 Module” for operation of the Timer0 module. An input change on PORTA change sets the RAIF (INTCON<0>) bit. The interrupt can be enabled/ disabled by setting/clearing the RAIE (INTCON<3>) bit. Plus, individual pins can be configured through the IOCA register. Note: FIGURE 12-7: PORTA INTERRUPT If a change on the I/O pin should occur when the read operation is being executed (start of the Q2 cycle), then the RAIF interrupt flag may not get set. INTERRUPT LOGIC IOC-RA0 IOCA0 IOC-RA1 IOCA1 IOC-RA2 IOCA2 IOC-RA3 IOCA3 IOC-RA4 IOCA4 IOC-RA5 IOCA5 TMR2IF TMR2IE TMR1IF TMR1IE C1IF C1IE C2IF C2IE T0IF T0IE INTF INTE RAIF RAIE Wake-up (If in Sleep mode) Interrupt to CPU PEIE GIE ADIF ADIE EEIF EEIE OSFIF OSFIE CCP1IF CCP1IE DS41202C-page 102 Preliminary 2004 Microchip Technology Inc. PIC16F684 FIGURE 12-8: INT PIN INTERRUPT TIMING Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 OSC1 CLKOUT (3) (4) INT pin (1) (1) INTF flag (INTCON<1>) Interrupt Latency (2) (5) GIE bit (INTCON<7>) INSTRUCTION FLOW PC Instruction Fetched Dummy Cycle Inst (PC) 0005h Inst (0004h) Inst (0005h) Dummy Cycle Inst (0004h) INTF flag is sampled here (every Q1). 2: Asynchronous interrupt latency = 3-4 TCY. Synchronous latency = 3 TCY, where TCY = instruction cycle time. Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction. 3: CLKOUT is available only in INTOSC and RC Oscillator modes. 4: For minimum width of INT pulse, refer to AC specifications in Section 15.0 “Electrical Specifications”. 5: INTF is enabled to be set any time during the Q4-Q1 cycles. TABLE 12-6: Address — Inst (PC + 1) Inst (PC – 1) 0004h PC + 1 PC + 1 Inst (PC) Instruction Executed Note 1: PC SUMMARY OF INTERRUPT REGISTERS Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Value on all other Resets Bit 1 Bit 0 Value on POR, BOD INTF RAIF 0000 0000 0000 0000 0Bh, 8Bh INTCON GIE PEIE T0IE INTE RAIE T0IF 0Ch PIR1 EEIF ADIF CCP1IF C2IF C1IF OSFIF TMR2IF TMR1IF 0000 0000 0000 0000 8Ch PIE1 EEIE ADIE CCP1IE C2IE C1IE OSFIE TMR2IE TMR1IE 0000 0000 0000 0000 Legend: x = unknown, u = unchanged, — = unimplemented read as ‘0’, q = value depends upon condition. Shaded cells are not used by the interrupt module. 2004 Microchip Technology Inc. Preliminary DS41202C-page 103 PIC16F684 12.5 Context Saving During Interrupts During an interrupt, only the return PC value is saved on the stack. Typically, users may wish to save key registers during an interrupt (e.g., W and Status registers). This must be implemented in software. Since the lower 16 bytes of all banks are common in the PIC16F684 (see Figure 2-2), temporary holding registers, W_TEMP and STATUS_TEMP, should be placed in here. These 16 locations do not require banking and therefore, make it easier to context save and restore. The same code shown in Example 12-1 can be used to: • • • • • Store the W register Store the Status register Execute the ISR code Restore the Status (and Bank Select Bit register) Restore the W register Note: The PIC16F684 normally does not require saving the PCLATH. However, if computed GOTOs are used in the ISR and the main code, the PCLATH must be saved and restored in the ISR. EXAMPLE 12-1: SAVING STATUS AND W REGISTERS IN RAM MOVWF SWAPF CLRF MOVWF : :(ISR) : SWAPF W_TEMP STATUS,W STATUS STATUS_TEMP MOVWF SWAPF SWAPF STATUS W_TEMP,F W_TEMP,W ;Copy ;Swap ;bank ;Save W to TEMP register status to be saved into W 0, regardless of current bank, Clears IRP,RP1,RP0 status to bank zero STATUS_TEMP register ;Insert user code here STATUS_TEMP,W DS41202C-page 104 ;Swap STATUS_TEMP register into W ;(sets bank to original state) ;Move W into Status register ;Swap W_TEMP ;Swap W_TEMP into W Preliminary 2004 Microchip Technology Inc. PIC16F684 12.6 Watchdog Timer (WDT) For PIC16F684, the WDT has been modified from previous PIC16 devices. The new WDT is code and functionally compatible with previous PIC16 WDT modules and adds a 16-bit prescaler to the WDT. This allows the user to have a scaler value for the WDT and TMR0 at the same time. In addition, the WDT time-out value can be extended to 268 seconds. WDT is cleared under certain conditions described in Table 12-7. A new prescaler has been added to the path between the INTRC and the multiplexers used to select the path for the WDT. This prescaler is 16 bits and can be programmed to divide the INTRC by 32 to 65536, giving the WDT a nominal range of 1 ms to 268s. 12.6.2 WDT CONTROL The WDTE bit is located in the Configuration Word register. When set, the WDT runs continuously. The WDT derives its time base from the 31 kHz LFINTOSC. The LTS bit does not reflect that the LFINTOSC is enabled. When the WDTE bit in the Configuration Word register is set, the SWDTEN bit (WDTCON<0>) has no effect. If WDTE is clear, then the SWDTEN bit can be used to enable and disable the WDT. Setting the bit will enable it and clearing the bit will disable it. The value of WDTCON is ‘---0 1000’ on all Resets. This gives a nominal time base of 16 ms, which is compatible with the time base generated with previous PIC16 microcontroller versions. The PSA and PS<2:0> bits (OPTION_REG) have the same function as in previous versions of the PIC16 Family of microcontrollers. See Section 5.0 “Timer0 Module” for more information. 12.6.1 Note: WDT OSCILLATOR When the Oscillator Start-up Timer (OST) is invoked, the WDT is held in Reset, because the WDT Ripple Counter is used by the OST to perform the oscillator delay count. When the OST count has expired, the WDT will begin counting (if enabled). FIGURE 12-9: WATCHDOG TIMER BLOCK DIAGRAM From TMR0 Clock Source 0 Prescaler(1) 16-bit WDT Prescaler 1 8 PSA 31 kHz LFINTOSC Clock PS<2:0> WDTPS<3:0> TO TMR0 0 1 PSA WDTE from the Configuration Word Register SWDTEN from WDTCON WDT Time-out Note 1: TABLE 12-7: This is the shared Timer0/WDT prescaler. See Section 5.4 “Prescaler” for more information. WDT STATUS Conditions WDT WDTE = 0 CLRWDT Command Cleared Oscillator Fail Detected Exit Sleep + System Clock = T1OSC, EXTRC, INTRC, EXTCLK Exit Sleep + System Clock = XT, HS, LP 2004 Microchip Technology Inc. Cleared until the end of OST Preliminary DS41202C-page 105 PIC16F684 REGISTER 12-3: WDTCON – WATCHDOG TIMER CONTROL REGISTER (ADDRESS: 18h) U-0 U-0 U-0 R/W-0 R/W-1 R/W-0 R/W-0 R/W-0 — — — WDTPS3 WDTPS2 WDTPS1 WDTPS0 SWDTEN bit 7 bit 0 bit 7-5 Unimplemented: Read as ‘0’ bit 4-1 WDTPS<3:0>: Watchdog Timer Period Select bits Bit Value = Prescale Rate 0000 = 1:32 0001 = 1:64 0010 = 1:128 0011 = 1:256 0100 = 1:512 (Reset value) 0101 = 1:1024 0110 = 1:2048 0111 = 1:4096 1000 = 1:8192 1001 = 1:16384 1010 = 1:32768 1011 = 1:65536 1100 = reserved 1101 = reserved 1110 = reserved 1111 = reserved bit 0 SWDTEN: Software Enable or Disable the Watchdog Timer(1) 1 = WDT is turned on 0 = WDT is turned off (Reset value) Note 1: If WDTE configuration bit = 1, then WDT is always enabled, irrespective of this control bit. If WDTE configuration bit = 0, then it is possible to turn WDT on/off with this control bit. Legend: TABLE 12-8: Address R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ -n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown SUMMARY OF WATCHDOG TIMER REGISTERS Name 18h WDTCON 81h OPTION_REG 2007h(1) CONFIG Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 — — — RAPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 CPD CP MCLRE PWRTE WDTE FOSC2 FOSC1 FOSC0 WDTPS3 WDTPS2 WSTPS1 WDTPS0 SWDTEN Legend: Shaded cells are not used by the Watchdog Timer. Note 1: See Register 12-1 for operation of all Configuration Word register bits. DS41202C-page 106 Preliminary 2004 Microchip Technology Inc. PIC16F684 12.7 Power-Down Mode (Sleep) The Power-down mode is entered by executing a SLEEP instruction. If the Watchdog Timer is enabled: • • • • • WDT will be cleared but keeps running. PD bit in the Status register is cleared. TO bit is set. Oscillator driver is turned off. I/O ports maintain the status they had before SLEEP was executed (driving high, low or high-impedance). For lowest current consumption in this mode, all I/O pins should be either at VDD or VSS, with no external circuitry drawing current from the I/O pin and the comparators and CVREF should be disabled. I/O pins that are high-impedance inputs should be pulled high or low externally to avoid switching currents caused by floating inputs. The T0CKI input should also be at VDD or VSS for lowest current consumption. The contribution from on-chip pull-ups on PORTA should be considered. The MCLR pin must be at a logic high level. Note: 12.7.1 It should be noted that a Reset generated by a WDT time-out does not drive MCLR pin low. WAKE-UP FROM SLEEP The device can wake-up from Sleep through one of the following events: 1. 2. 3. External Reset input on MCLR pin. Watchdog Timer wake-up (if WDT was enabled). Interrupt from RA2/INT pin, PORTA change or a peripheral interrupt. The first event will cause a device Reset. The two latter events are considered a continuation of program execution. The TO and PD bits in the Status register can be used to determine the cause of device Reset. The PD bit, which is set on power-up, is cleared when Sleep is invoked. TO bit is cleared if WDT wake-up occurred. The following peripheral interrupts can wake the device from Sleep: 1. 2. 3. 4. 5. 6. 7. 8. TMR1 interrupt. Timer1 must be operating as an asynchronous counter. ECCP Capture mode interrupt. Special event trigger (Timer1 in Asynchronous mode using an external clock). A/D conversion (when A/D clock source is RC). EEPROM write operation completion. Comparator output changes state. Interrupt-on-change. External Interrupt from INT pin. 2004 Microchip Technology Inc. Other peripherals cannot generate interrupts since during Sleep, no on-chip clocks are present. When the SLEEP instruction is being executed, the next instruction (PC + 1) is prefetched. For the device to wake-up through an interrupt event, the corresponding interrupt enable bit must be set (enabled). Wake-up is regardless of the state of the GIE bit. If the GIE bit is clear (disabled), the device continues execution at the instruction after the SLEEP instruction. If the GIE bit is set (enabled), the device executes the instruction after the SLEEP instruction, then branches to the interrupt address (0004h). In cases where the execution of the instruction following SLEEP is not desirable, the user should have a NOP after the SLEEP instruction. Note: If the global interrupts are disabled (GIE is cleared), but any interrupt source has both its interrupt enable bit and the corresponding interrupt flag bits set, the device will immediately wake-up from Sleep. The SLEEP instruction is completely executed. The WDT is cleared when the device wakes up from Sleep, regardless of the source of wake-up. 12.7.2 WAKE-UP USING INTERRUPTS When global interrupts are disabled (GIE cleared) and any interrupt source has both its interrupt enable bit and interrupt flag bit set, one of the following will occur: • If the interrupt occurs before the execution of a SLEEP instruction, the SLEEP instruction will complete as a NOP. Therefore, the WDT and WDT prescaler and postscaler (if enabled) will not be cleared, the TO bit will not be set and the PD bit will not be cleared. • If the interrupt occurs during or after the execution of a SLEEP instruction, the device will immediately wake-up from Sleep. The SLEEP instruction will be completely executed before the wake-up. Therefore, the WDT and WDT prescaler and postscaler (if enabled) will be cleared, the TO bit will be set and the PD bit will be cleared. Even if the flag bits were checked before executing a SLEEP instruction, it may be possible for flag bits to become set before the SLEEP instruction completes. To determine whether a SLEEP instruction executed, test the PD bit. If the PD bit is set, the SLEEP instruction was executed as a NOP. To ensure that the WDT is cleared, a CLRWDT instruction should be executed before a SLEEP instruction. Preliminary DS41202C-page 107 PIC16F684 FIGURE 12-10: WAKE-UP FROM SLEEP THROUGH INTERRUPT Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 OSC1 TOST(2) CLKOUT(4) INT pin INTF flag (INTCON<1>) Interrupt Latency (3) GIE bit (INTCON<7>) Processor in Sleep Instruction Flow PC Instruction Fetched Instruction Executed Note 12.8 PC Inst(PC) = Sleep Inst(PC – 1) PC + 1 PC + 2 Inst(PC + 1) Inst(PC + 2) Sleep Inst(PC + 1) 12.9 PC + 2 Dummy Cycle 0004h 0005h Inst(0004h) Inst(0005h) Dummy Cycle Inst(0004h) 1: XT, HS or LP Oscillator mode assumed. 2: TOST = 1024 TOSC (drawing not to scale). This delay does not apply to EC and RC Oscillator modes. 3: GIE = ‘1’ assumed. In this case after wake-up, the processor jumps to 0004h. If GIE = ‘0’, execution will continue in-line. 4: CLKOUT is not available in XT, HS, LP or EC oscillator modes, but shown here for timing reference. Code Protection If the code protection bit(s) have not been programmed, the on-chip program memory can be read out using ICSP™ for verification purposes. Note: PC + 2 The entire data EEPROM and Flash program memory will be erased when the code protection is turned off. See the “PIC12F6XX/16F6XX Memory Programming Specification” (DS41204) for more information. ID Locations Four memory locations (2000h-2003h) are designated as ID locations where the user can store checksum or other code identification numbers. These locations are not accessible during normal execution but are readable and writable during Program/Verify mode. Only the Least Significant 7 bits of the ID locations are used. 12.10 In-Circuit Serial Programming The PIC16F684 microcontrollers can be serially programmed while in the end application circuit. This is simply done with two lines for clock and data and three other lines for: This allows customers to manufacture boards with unprogrammed devices and then program the microcontroller just before shipping the product. This also allows the most recent firmware or a custom firmware to be programmed. The device is placed into a Program/Verify mode by holding the RA0 and RA1 pins low, while raising the MCLR (VPP) pin from VIL to VIHH. See the “PIC12F6XX/ 16F6XX Memory Programming Specification” (DS41204) for more information. RA0 becomes the programming data and RA1 becomes the programming clock. Both RA0 and RA1 are Schmitt Trigger inputs in this mode. After Reset, to place the device into Program/Verify mode, the Program Counter (PC) is at location 00h. A 6-bit command is then supplied to the device. Depending on the command, 14 bits of program data are then supplied to or from the device, depending on whether the command was a load or a read. For complete details of serial programming, please refer to the “PIC12F6XX/16F6XX Memory Programming Specification” (DS41204). A typical In-Circuit Serial Programming connection is shown in Figure 12-11. • power • ground • programming voltage DS41202C-page 108 Preliminary 2004 Microchip Technology Inc. PIC16F684 FIGURE 12-11: TYPICAL IN-CIRCUIT SERIAL PROGRAMMING CONNECTION To Normal Connections External Connector Signals * PIC16F684 +5V VDD 0V VSS VPP MCLR/VPP/RA3 CLK RA1 Data I/O RA0 * DEBUGGER RESOURCES Resource Description I/O pins ICDCLK, ICDDATA Stack 1 level Program Memory Address 0h must be NOP 700h-7FFh For more information, see “MPLAB® ICD 2 In-Circuit Debugger User’s Guide” (DS51331), available on Microchip’s web site (www.microchip.com). FIGURE 12-12: 20-PIN ICD PINOUT 20-Pin PDIP In-Circuit Debug Device * To Normal Connections * Isolation devices (as required) NC 1 20 ICDMCLR/VPP VDD RA5 RA4 RA3 RC5 RC4 RC3 ICD 2 19 3 4 5 6 7 8 9 10 PIC16F684 -ICD * TABLE 12-9: 18 17 16 15 14 13 12 11 ICDCLK ICDDATA Vss RA0 RA1 RA2 RC0 RC1 RC2 NC 12.11 In-Circuit Debugger Since in-circuit debugging requires access to the data and MCLR pins, MPLAB® ICD 2 development with an 14-pin device is not practical. A special 20-pin PIC16F684 ICD device is used with MPLAB ICD 2 to provide separate clock, data and MCLR pins and frees all normally available pins to the user. A special debugging adapter allows the ICD device to be used in place of a PIC16F684 device. The debugging adapter is the only source of the ICD device. When the ICD pin on the PIC16F684 ICD device is held low, the In-Circuit Debugger functionality is enabled. This function allows simple debugging functions when used with MPLAB ICD 2. When the microcontroller has this feature enabled, some of the resources are not available for general use. Table 12-9 shows which features are consumed by the background debugger. 2004 Microchip Technology Inc. Preliminary DS41202C-page 109 PIC16F684 NOTES: DS41202C-page 110 Preliminary 2004 Microchip Technology Inc. PIC16F684 13.0 INSTRUCTION SET SUMMARY The PIC16F684 instruction set is highly orthogonal and is comprised of three basic categories: • Byte-oriented operations • Bit-oriented operations • Literal and control operations For example, a CLRF GPIO instruction will read GPIO, clear all the data bits, then write the result back to GPIO. This example would have the unintended result of clearing the condition that set the GPIF flag. TABLE 13-1: Each PIC16 instruction is a 14-bit word divided into an opcode, which specifies the instruction type and one or more operands, which further specify the operation of the instruction. The formats for each of the categories is presented in Figure 13-1, while the various opcode fields are summarized in Table 13-1. Field Table 13-2 lists the instructions recognized by the MPASMTM assembler. A complete description of each instruction is also available in the “PICmicro® MidRange MCU Family Reference Manual” (DS33023). For byte-oriented instructions, ‘f’ represents a file register designator and ‘d’ represents a destination designator. The file register designator specifies which file register is to be used by the instruction. The destination designator specifies where the result of the operation is to be placed. If ‘d’ is zero, the result is placed in the W register. If ‘d’ is one, the result is placed in the file register specified in the instruction. For bit-oriented instructions, ‘b’ represents a bit field designator, which selects the bit affected by the operation, while ‘f’ represents the address of the file in which the bit is located. Register file address (0x00 to 0x7F) W Working register (accumulator) b Bit address within an 8-bit file register k Literal field, constant data or label x Don’t care location (= 0 or 1). The assembler will generate code with x = 0. It is the recommended form of use for compatibility with all Microchip software tools. d Destination select; d = 0: store result in W, d = 1: store result in file register f. Default is d = 1. PC Program Counter TO Time-out bit PD Power-down bit FIGURE 13-1: One instruction cycle consists of four oscillator periods; for an oscillator frequency of 4 MHz, this gives a normal instruction execution time of 1 µs. All instructions are executed within a single instruction cycle, unless a conditional test is true, or the program counter is changed as a result of an instruction. When this occurs, the execution takes two instruction cycles, with the second cycle executed as a NOP. To maintain upward compatibility with future products, do not use the OPTION and TRIS instructions. All instruction examples use the format ‘0xhh’ to represent a hexadecimal number, where ‘h’ signifies a hexadecimal digit. 13.1 READ-MODIFY-WRITE OPERATIONS GENERAL FORMAT FOR INSTRUCTIONS Byte-oriented file register operations 13 8 7 6 OPCODE d f (FILE #) 0 d = 0 for destination W d = 1 for destination f f = 7-bit file register address Bit-oriented file register operations 13 10 9 7 6 OPCODE b (BIT #) f (FILE #) 0 b = 3-bit bit address f = 7-bit file register address Literal and control operations General 13 8 7 OPCODE 0 k (literal) k = 8-bit immediate value CALL and GOTO instructions only 13 Any instruction that specifies a file register as part of the instruction performs a Read-Modify-Write (R-M-W) operation. The register is read, the data is modified, and the result is stored according to either the instruction, or the destination designator ‘d’. A read operation is performed on a register even if the instruction writes to that register. 2004 Microchip Technology Inc. Description f For literal and control operations, ‘k’ represents an 8-bit or 11-bit constant, or literal value. Note: OPCODE FIELD DESCRIPTIONS Preliminary 11 OPCODE 10 0 k (literal) k = 11-bit immediate value DS41202C-page 111 PIC16F684 TABLE 13-2: PIC16F684 INSTRUCTION SET Mnemonic, Operands 14-Bit Opcode Description Cycles MSb LSb Status Affected Notes BYTE-ORIENTED FILE REGISTER OPERATIONS ADDWF ANDWF CLRF CLRW COMF DECF DECFSZ INCF INCFSZ IORWF MOVF MOVWF NOP RLF RRF SUBWF SWAPF XORWF f, d f, d f – f, d f, d f, d f, d f, d f, d f, d f – f, d f, d f, d f, d f, d Add W and f AND W with f Clear f Clear W Complement f Decrement f Decrement f, Skip if 0 Increment f Increment f, Skip if 0 Inclusive OR W with f Move f Move W to f No Operation Rotate Left f through Carry Rotate Right f through Carry Subtract W from f Swap nibbles in f Exclusive OR W with f BCF BSF BTFSC BTFSS f, b f, b f, b f, b Bit Clear f Bit Set f Bit Test f, Skip if Clear Bit Test f, Skip if Set 1 1 1 1 1 1 1(2) 1 1(2) 1 1 1 1 1 1 1 1 1 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0111 0101 0001 0001 1001 0011 1011 1010 1111 0100 1000 0000 0000 1101 1100 0010 1110 0110 dfff dfff lfff 0xxx dfff dfff dfff dfff dfff dfff dfff lfff 0xx0 dfff dfff dfff dfff dfff ffff ffff ffff xxxx ffff ffff ffff ffff ffff ffff ffff ffff 0000 ffff ffff ffff ffff ffff 00bb 01bb 10bb 11bb bfff bfff bfff bfff ffff ffff ffff ffff 111x 1001 0kkk 0000 1kkk 1000 00xx 0000 01xx 0000 0000 110x 1010 kkkk kkkk kkkk 0110 kkkk kkkk kkkk 0000 kkkk 0000 0110 kkkk kkkk kkkk kkkk kkkk 0100 kkkk kkkk kkkk 1001 kkkk 1000 0011 kkkk kkkk C, DC, Z Z Z Z Z Z Z Z Z C C C, DC, Z Z 1, 2 1, 2 2 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 BIT-ORIENTED FILE REGISTER OPERATIONS 1 1 1 (2) 1 (2) 01 01 01 01 1, 2 1, 2 3 3 LITERAL AND CONTROL OPERATIONS ADDLW ANDLW CALL CLRWDT GOTO IORLW MOVLW RETFIE RETLW RETURN SLEEP SUBLW XORLW Note 1: 2: 3: Note: k k k – k k k – k – – k k Add literal and W AND literal with W Call Subroutine Clear Watchdog Timer Go to address Inclusive OR literal with W Move literal to W Return from interrupt Return with literal in W Return from Subroutine Go into Standby mode Subtract W from literal Exclusive OR literal with W 1 1 2 1 2 1 1 2 2 2 1 1 1 11 11 10 00 10 11 11 00 11 00 00 11 11 C, DC, Z Z TO, PD Z TO, PD C, DC, Z Z When an I/O register is modified as a function of itself (e.g., MOVF GPIO, 1), the value used will be that value present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is driven low by an external device, the data will be written back with a ‘0’. If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be cleared if assigned to the Timer0 module. If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle is executed as a NOP. Additional information on the mid-range instruction set is available in the “PICmicro® Mid-Range MCU Family Reference Manual” (DS33023). DS41202C-page 112 Preliminary 2004 Microchip Technology Inc. PIC16F684 13.2 Instruction Descriptions ADDLW Add literal and W Syntax: [ label ] ADDLW Operands: 0 ≤ k ≤ 255 Operation: (W) + k → (W) Status Affected: C, DC, Z Description: The contents of the W register are added to the eight-bit literal ‘k’ and the result is placed in the W register. k BCF Bit Clear f Syntax: [ label ] BCF Operands: 0 ≤ f ≤ 127 0≤b≤7 Operation: 0 → (f<b>) Status Affected: None Description: Bit ‘b’ in register ‘f’ is cleared. BSF Bit Set f Syntax: [ label ] BSF f,b ADDWF Add W and f Syntax: [ label ] ADDWF Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operands: 0 ≤ f ≤ 127 0≤b≤7 Operation: (W) + (f) → (destination) Operation: 1 → (f<b>) Status Affected: C, DC, Z Status Affected: None Description: Add the contents of the W register with register ‘f’. If ‘d’ is ‘0’, the result is stored in the W register. If ‘d’ is ‘1’, the result is stored back in register ‘f’. Description: Bit ‘b’ in register ‘f’ is set. ANDLW AND literal with W BTFSC Bit Test, Skip if Clear Syntax: [ label ] ANDLW Syntax: [ label ] BTFSC f,b Operands: 0 ≤ k ≤ 255 Operands: Operation: (W) .AND. (k) → (W) 0 ≤ f ≤ 127 0≤b≤7 Status Affected: Z Operation: skip if (f<b>) = 0 Description: The contents of W register are AND’ed with the eight-bit literal ‘k’. The result is placed in the W register. Status Affected: None Description: If bit ‘b’ in register ‘f’ is ‘1’, the next instruction is executed. If bit ‘b’, in register ‘f’, is ‘0’, the next instruction is discarded, and a NOP is executed instead, making this a 2-cycle instruction. ANDWF f,d k AND W with f Syntax: [ label ] ANDWF Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operation: (W) .AND. (f) → (destination) f,d Status Affected: Z Description: AND the W register with register ‘f’. If ‘d’ is ‘0’, the result is stored in the W register. If ‘d’ is ‘1’, the result is stored back in register ‘f’. 2004 Microchip Technology Inc. f,b Preliminary DS41202C-page 113 PIC16F684 BTFSS Bit Test f, Skip if Set CLRWDT Clear Watchdog Timer Syntax: [ label ] BTFSS f,b Syntax: [ label ] CLRWDT Operands: 0 ≤ f ≤ 127 0≤b<7 Operands: None Operation: 00h → WDT 0 → WDT prescaler, 1 → TO 1 → PD Status Affected: TO, PD Description: CLRWDT instruction resets the Watchdog Timer. It also resets the prescaler of the WDT. Status bits TO and PD are set. Operation: skip if (f<b>) = 1 Status Affected: None Description: If bit ‘b’ in register ‘f’ is ‘0’, the next instruction is executed. If bit ‘b’ is ‘1’, then the next instruction is discarded and a NOP is executed instead, making this a 2-cycle instruction. CALL Call Subroutine COMF Complement f Syntax: [ label ] CALL k Syntax: [ label ] COMF Operands: 0 ≤ k ≤ 2047 Operands: Operation: (PC)+ 1→ TOS, k → PC<10:0>, (PCLATH<4:3>) → PC<12:11> 0 ≤ f ≤ 127 d ∈ [0,1] Operation: (f) → (destination) Status Affected: Z Description: The contents of register ‘f’ are complemented. If ‘d’ is ‘0’, the result is stored in W. If ‘d’ is ‘1’, the result is stored back in register ‘f’. DECF Decrement f Syntax: [ label ] DECF f,d f,d Status Affected: None Description: Call Subroutine. First, return address (PC + 1) is pushed onto the stack. The eleven-bit immediate address is loaded into PC bits <10:0>. The upper bits of the PC are loaded from PCLATH. CALL is a two-cycle instruction. CLRF Clear f Syntax: [ label ] CLRF Operands: 0 ≤ f ≤ 127 Operands: Operation: 00h → (f) 1→Z 0 ≤ f ≤ 127 d ∈ [0,1] Operation: (f) - 1 → (destination) Status Affected: Z Status Affected: Z Description: The contents of register ‘f’ are cleared and the Z bit is set. Description: Decrement register ‘f’. If ‘d’ is ‘0’, the result is stored in the W register. If ‘d’ is ‘1’, the result is stored back in register ‘f’. CLRW Clear W Syntax: [ label ] CLRW f Operands: None Operation: 00h → (W) 1→Z Status Affected: Z Description: W register is cleared. Zero bit (Z) is set. DS41202C-page 114 Preliminary 2004 Microchip Technology Inc. PIC16F684 DECFSZ Decrement f, Skip if 0 INCFSZ Increment f, Skip if 0 Syntax: [ label ] DECFSZ f,d Syntax: [ label ] Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operation: (f) - 1 → (destination); skip if result = 0 Operation: (f) + 1 → (destination), skip if result = 0 Status Affected: None Status Affected: None Description: The contents of register ‘f’ are decremented. If ‘d’ is ‘0’, the result is placed in the W register. If ‘d’ is ‘1’, the result is placed back in register ‘f’. If the result is ‘1’, the next instruction is executed. If the result is ‘0’, then a NOP is executed instead, making it a 2-cycle instruction. Description: The contents of register ‘f’ are incremented. If ‘d’ is ‘0’, the result is placed in the W register. If ‘d’ is ‘1’, the result is placed back in register ‘f’. If the result is ‘1’, the next instruction is executed. If the result is ‘0’, a NOP is executed instead, making it a 2-cycle instruction. GOTO Unconditional Branch IORLW Syntax: [ label ] Syntax: [ label ] Operands: 0 ≤ k ≤ 2047 Operands: 0 ≤ k ≤ 255 Operation: k → PC<10:0> PCLATH<4:3> → PC<12:11> Operation: (W) .OR. k → (W) Status Affected: Z Status Affected: None Description: Description: GOTO is an unconditional branch. The eleven-bit immediate value is loaded into PC bits <10:0>. The upper bits of PC are loaded from PCLATH<4:3>. GOTO is a two-cycle instruction. The contents of the W register are OR’ed with the eight-bit literal ‘k’. The result is placed in the W register. INCF Increment f IORWF Inclusive OR W with f Syntax: [ label ] Syntax: [ label ] Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operation: (f) + 1 → (destination) Operation: (W) .OR. (f) → (destination) Status Affected: Z Status Affected: Z Description: The contents of register ‘f’ are incremented. If ‘d’ is ‘0’, the result is placed in the W register. If ‘d’ is ‘1’, the result is placed back in register ‘f’. Description: Inclusive OR the W register with register ‘f’. If ‘d’ is ‘0’, the result is placed in the W register. If ‘d’ is ‘1’, the result is placed back in register ‘f’. GOTO k INCF f,d 2004 Microchip Technology Inc. Preliminary INCFSZ f,d Inclusive OR literal with W IORLW k IORWF f,d DS41202C-page 115 PIC16F684 MOVF Move f Syntax: [ label ] Operands: 0 ≤ f ≤ 127 d ∈ [0,1] MOVF f,d MOVWF Move W to f Syntax: [ label ] MOVWF Operands: 0 ≤ f ≤ 127 Operation: (W) → (f) f Operation: (f) → (dest) Status Affected: None Status Affected: Z Description: Description: The contents of register f is moved to a destination dependent upon the status of d. If d = 0, destination is W register. If d = 1, the destination is file register f itself. d = 1 is useful to test a file register since status flag Z is affected. Move data from W register to register ‘f’. Words: 1 Cycles: 1 Words: 1 Cycles: 1 Example MOVF Example MOVW F OPTION Before Instruction OPTION = W = After Instruction OPTION = W = FSR, 0 0xFF 0x4F 0x4F 0x4F After Instruction W = value in FSR register Z = 1 MOVLW Move literal to W NOP No Operation Syntax: [ label ] Syntax: [ label ] Operands: 0 ≤ k ≤ 255 Operands: None Operation: k → (W) Operation: No operation Status Affected: None Status Affected: None Description: The eight bit literal ‘k’ is loaded into W register. The don’t cares will assemble as ‘0’s. Description: No operation. Words: 1 Cycles: 1 Words: 1 Cycles: 1 Example MOVLW k Example MOVLW NOP 0x5A After Instruction W = DS41202C-page 116 NOP 0x5A Preliminary 2004 Microchip Technology Inc. PIC16F684 RETFIE Return from Interrupt RETURN Return from Subroutine Syntax: [ label ] Syntax: [ label ] Operands: None Operands: None Operation: TOS → PC, 1 → GIE Operation: TOS → PC Status Affected: None Status Affected: None Description: Description: Return from Interrupt. Stack is POPed and Top-of-Stack (TOS) is loaded in the PC. Interrupts are enabled by setting Global Interrupt Enable bit, GIE (INTCON<7>). This is a two-cycle instruction. Return from subroutine. The stack is POPed and the top of the stack (TOS) is loaded into the program counter. This is a two-cycle instruction. Words: 1 Cycles: 2 Example RETFIE RETURN RETFIE After Interrupt PC = GIE = TOS 1 RETLW Return with literal in W RLF Rotate Left f through Carry Syntax: [ label ] Syntax: [ label ] Operands: 0 ≤ k ≤ 255 Operands: Operation: k → (W); TOS → PC 0 ≤ f ≤ 127 d ∈ [0,1] Operation: See description below Status Affected: None Status Affected: C Description: The W register is loaded with the eight bit literal ‘k’. The program counter is loaded from the top of the stack (the return address). This is a two-cycle instruction. Description: The contents of register ‘f’ are rotated one bit to the left through the Carry flag. If ‘d’ is ‘0’, the result is placed in the W register. If ‘d’ is ‘1’, the result is stored back in register ‘f’. RETLW k Words: 1 Cycles: 2 Example CALL TABLE;W contains table ;offset value • ;W now has table value • • ADDWF PC ;W = offset RETLW k1 ;Begin table RETLW k2 ; • • • RETLW kn ; End of table TABLE RLF C Words: 1 Cycles: 1 Example RLF f,d Register f REG1,0 Before Instruction REG1 C = = 1110 0110 0 = = = 1110 0110 1100 1100 1 After Instruction REG1 W C Before Instruction W = 0x07 After Instruction W = value of k8 2004 Microchip Technology Inc. Preliminary DS41202C-page 117 PIC16F684 RRF Rotate Right f through Carry SUBWF Subtract W from f Syntax: [ label ] Syntax: [ label ] SUBWF f,d Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operation: See description below Operation: (f) - (W) → (destination) Status Affected: C Status Affected: C, DC, Z Description: The contents of register ‘f’ are rotated one bit to the right through the Carry flag. If ‘d’ is ‘0’, the result is placed in the W register. If ‘d’ is ‘1’, the result is placed back in register ‘f’. Description: RRF f,d C Subtract (2’s complement method) W register from register ‘f’. If ‘d’ is ‘0’, the result is stored in the W register. If ‘d’ is ‘1’, the result is stored back in register ‘f’. Register f SWAPF Swap Nibbles in f SLEEP Enter Sleep mode Syntax: [ label ] SLEEP Syntax: [ label ] SWAPF f,d Operands: None Operands: Operation: 00h → WDT, 0 → WDT prescaler, 1 → TO, 0 → PD 0 ≤ f ≤ 127 d ∈ [0,1] Operation: (f<3:0>) → (destination<7:4>), (f<7:4>) → (destination<3:0>) Status Affected: None Description: The upper and lower nibbles of register ‘f’ are exchanged. If ‘d’ is ‘0’, the result is placed in the W register. If ‘d’ is ‘1’, the result is placed in register ‘f’. Status Affected: TO, PD Description: The power-down Status bit, PD is cleared. Time-out Status bit, TO is set. Watchdog Timer and its prescaler are cleared. The processor is put into Sleep mode with the oscillator stopped. SUBLW Subtract W from literal XORLW Exclusive OR literal with W Syntax: [ label ] SUBLW k Syntax: [ label ] XORLW k Operands: 0 ≤ k ≤ 255 Operands: 0 ≤ k ≤ 255 Operation: k - (W) → (W) Operation: (W) .XOR. k → (W) Status Affected: C, DC, Z Status Affected: Z Description: Description: The contents of the W register are XOR’ed with the eight-bit literal ‘k’. The result is placed in the W register. The W register is subtracted (2’s complement method) from the eight-bit literal ‘k’. The result is placed in the W register. DS41202C-page 118 Preliminary 2004 Microchip Technology Inc. PIC16F684 XORWF Exclusive OR W with f Syntax: [ label ] XORWF Operands: 0 ≤ f ≤ 127 d ∈ [0,1] Operation: (W) .XOR. (f) → (destination) Status Affected: Z Description: Exclusive OR the contents of the W register with register ‘f’. If ‘d’ is ‘0’, the result is stored in the W register. If ‘d’ is ‘1’, the result is stored back in register ‘f’. 2004 Microchip Technology Inc. f,d Preliminary DS41202C-page 119 PIC16F684 NOTES: DS41202C-page 120 Preliminary 2004 Microchip Technology Inc. PIC16F684 14.0 DEVELOPMENT SUPPORT 14.1 The PICmicro® microcontrollers are supported with a full range of hardware and software development tools: • Integrated Development Environment - MPLAB® IDE Software • Assemblers/Compilers/Linkers - MPASMTM Assembler - MPLAB C17 and MPLAB C18 C Compilers - MPLINKTM Object Linker/ MPLIBTM Object Librarian - MPLAB C30 C Compiler - MPLAB ASM30 Assembler/Linker/Library • Simulators - MPLAB SIM Software Simulator - MPLAB dsPIC30 Software Simulator • Emulators - MPLAB ICE 2000 In-Circuit Emulator - MPLAB ICE 4000 In-Circuit Emulator • In-Circuit Debugger - MPLAB ICD 2 • Device Programmers - PRO MATE® II Universal Device Programmer - PICSTART® Plus Development Programmer - MPLAB PM3 Device Programmer • Low-Cost Demonstration Boards - PICDEMTM 1 Demonstration Board - PICDEM.netTM Demonstration Board - PICDEM 2 Plus Demonstration Board - PICDEM 3 Demonstration Board - PICDEM 4 Demonstration Board - PICDEM 17 Demonstration Board - PICDEM 18R Demonstration Board - PICDEM LIN Demonstration Board - PICDEM USB Demonstration Board • Evaluation Kits - KEELOQ® - PICDEM MSC - microID® - CAN - PowerSmart® - Analog MPLAB Integrated Development Environment Software The MPLAB IDE software brings an ease of software development previously unseen in the 8/16-bit microcontroller market. The MPLAB IDE is a Windows® based application that contains: • An interface to debugging tools - simulator - programmer (sold separately) - emulator (sold separately) - in-circuit debugger (sold separately) • A full-featured editor with color coded context • A multiple project manager • Customizable data windows with direct edit of contents • High-level source code debugging • Mouse over variable inspection • Extensive on-line help The MPLAB IDE allows you to: • Edit your source files (either assembly or C) • One touch assemble (or compile) and download to PICmicro emulator and simulator tools (automatically updates all project information) • Debug using: - source files (assembly or C) - mixed assembly and C - machine code MPLAB IDE supports multiple debugging tools in a single development paradigm, from the cost effective simulators, through low-cost in-circuit debuggers, to full-featured emulators. This eliminates the learning curve when upgrading to tools with increasing flexibility and power. 14.2 MPASM Assembler The MPASM assembler is a full-featured, universal macro assembler for all PICmicro MCUs. The MPASM assembler generates relocatable object files for the MPLINK object linker, Intel® standard HEX files, MAP files to detail memory usage and symbol reference, absolute LST files that contain source lines and generated machine code and COFF files for debugging. The MPASM assembler features include: • Integration into MPLAB IDE projects • User defined macros to streamline assembly code • Conditional assembly for multi-purpose source files • Directives that allow complete control over the assembly process 2004 Microchip Technology Inc. Preliminary DS41202C-page 121 PIC16F684 14.3 MPLAB C17 and MPLAB C18 C Compilers 14.6 The MPLAB C17 and MPLAB C18 Code Development Systems are complete ANSI C compilers for Microchip’s PIC17CXXX and PIC18CXXX family of microcontrollers. These compilers provide powerful integration capabilities, superior code optimization and ease of use not found with other compilers. For easy source level debugging, the compilers provide symbol information that is optimized to the MPLAB IDE debugger. 14.4 MPLINK Object Linker/ MPLIB Object Librarian The MPLINK object linker combines relocatable objects created by the MPASM assembler and the MPLAB C17 and MPLAB C18 C compilers. It can link relocatable objects from precompiled libraries, using directives from a linker script. The MPLIB object librarian manages the creation and modification of library files of precompiled code. When a routine from a library is called from a source file, only the modules that contain that routine will be linked in with the application. This allows large libraries to be used efficiently in many different applications. The object linker/library features include: • Efficient linking of single libraries instead of many smaller files • Enhanced code maintainability by grouping related modules together • Flexible creation of libraries with easy module listing, replacement, deletion and extraction 14.5 MPLAB C30 C Compiler MPLAB C30 is distributed with a complete ANSI C standard library. All library functions have been validated and conform to the ANSI C library standard. The library includes functions for string manipulation, dynamic memory allocation, data conversion, timekeeping and math functions (trigonometric, exponential and hyperbolic). The compiler provides symbolic information for high-level source debugging with the MPLAB IDE. DS41202C-page 122 MPLAB ASM30 assembler produces relocatable machine code from symbolic assembly language for dsPIC30F devices. MPLAB C30 compiler uses the assembler to produce it’s object file. The assembler generates relocatable object files that can then be archived or linked with other relocatable object files and archives to create an executable file. Notable features of the assembler include: • • • • • • Support for the entire dsPIC30F instruction set Support for fixed-point and floating-point data Command line interface Rich directive set Flexible macro language MPLAB IDE compatibility 14.7 MPLAB SIM Software Simulator The MPLAB SIM software simulator allows code development in a PC hosted environment by simulating the PICmicro series microcontrollers on an instruction level. On any given instruction, the data areas can be examined or modified and stimuli can be applied from a file, or user defined key press, to any pin. The execution can be performed in Single-Step, Execute Until Break or Trace mode. The MPLAB SIM simulator fully supports symbolic debugging using the MPLAB C17 and MPLAB C18 C Compilers, as well as the MPASM assembler. The software simulator offers the flexibility to develop and debug code outside of the laboratory environment, making it an excellent, economical software development tool. 14.8 The MPLAB C30 C compiler is a full-featured, ANSI compliant, optimizing compiler that translates standard ANSI C programs into dsPIC30F assembly language source. The compiler also supports many command line options and language extensions to take full advantage of the dsPIC30F device hardware capabilities and afford fine control of the compiler code generator. MPLAB ASM30 Assembler, Linker and Librarian MPLAB SIM30 Software Simulator The MPLAB SIM30 software simulator allows code development in a PC hosted environment by simulating the dsPIC30F series microcontrollers on an instruction level. On any given instruction, the data areas can be examined or modified and stimuli can be applied from a file, or user defined key press, to any of the pins. The MPLAB SIM30 simulator fully supports symbolic debugging using the MPLAB C30 C Compiler and MPLAB ASM30 assembler. The simulator runs in either a Command Line mode for automated tasks, or from MPLAB IDE. This high-speed simulator is designed to debug, analyze and optimize time intensive DSP routines. Preliminary 2004 Microchip Technology Inc. PIC16F684 14.9 MPLAB ICE 2000 High-Performance Universal In-Circuit Emulator 14.11 MPLAB ICD 2 In-Circuit Debugger The MPLAB ICE 2000 universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for PICmicro microcontrollers. Software control of the MPLAB ICE 2000 in-circuit emulator is advanced by the MPLAB Integrated Development Environment, which allows editing, building, downloading and source debugging from a single environment. The MPLAB ICE 2000 is a full-featured emulator system with enhanced trace, trigger and data monitoring features. Interchangeable processor modules allow the system to be easily reconfigured for emulation of different processors. The universal architecture of the MPLAB ICE in-circuit emulator allows expansion to support new PICmicro microcontrollers. The MPLAB ICE 2000 in-circuit emulator system has been designed as a real-time emulation system with advanced features that are typically found on more expensive development tools. The PC platform and Microsoft® Windows 32-bit operating system were chosen to best make these features available in a simple, unified application. 14.10 MPLAB ICE 4000 High-Performance Universal In-Circuit Emulator The MPLAB ICE 4000 universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for highend PICmicro microcontrollers. Software control of the MPLAB ICE in-circuit emulator is provided by the MPLAB Integrated Development Environment, which allows editing, building, downloading and source debugging from a single environment. The MPLAB ICD 4000 is a premium emulator system, providing the features of MPLAB ICE 2000, but with increased emulation memory and high-speed performance for dsPIC30F and PIC18XXXX devices. Its advanced emulator features include complex triggering and timing, up to 2 Mb of emulation memory and the ability to view variables in real-time. The MPLAB ICE 4000 in-circuit emulator system has been designed as a real-time emulation system with advanced features that are typically found on more expensive development tools. The PC platform and Microsoft Windows 32-bit operating system were chosen to best make these features available in a simple, unified application. 2004 Microchip Technology Inc. Microchip’s In-Circuit Debugger, MPLAB ICD 2, is a powerful, low-cost, run-time development tool, connecting to the host PC via an RS-232 or high-speed USB interface. This tool is based on the Flash PICmicro MCUs and can be used to develop for these and other PICmicro microcontrollers. The MPLAB ICD 2 utilizes the in-circuit debugging capability built into the Flash devices. This feature, along with Microchip’s In-Circuit Serial ProgrammingTM (ICSPTM) protocol, offers cost effective in-circuit Flash debugging from the graphical user interface of the MPLAB Integrated Development Environment. This enables a designer to develop and debug source code by setting breakpoints, single-stepping and watching variables, CPU status and peripheral registers. Running at full speed enables testing hardware and applications in real-time. MPLAB ICD 2 also serves as a development programmer for selected PICmicro devices. 14.12 PRO MATE II Universal Device Programmer The PRO MATE II is a universal, CE compliant device programmer with programmable voltage verification at VDDMIN and VDDMAX for maximum reliability. It features an LCD display for instructions and error messages and a modular detachable socket assembly to support various package types. In Stand-Alone mode, the PRO MATE II device programmer can read, verify and program PICmicro devices without a PC connection. It can also set code protection in this mode. 14.13 MPLAB PM3 Device Programmer The MPLAB PM3 is a universal, CE compliant device programmer with programmable voltage verification at VDDMIN and VDDMAX for maximum reliability. It features a large LCD display (128 x 64) for menus and error messages and a modular detachable socket assembly to support various package types. The ICSP™ cable assembly is included as a standard item. In StandAlone mode, the MPLAB PM3 device programmer can read, verify and program PICmicro devices without a PC connection. It can also set code protection in this mode. MPLAB PM3 connects to the host PC via an RS232 or USB cable. MPLAB PM3 has high-speed communications and optimized algorithms for quick programming of large memory devices and incorporates an SD/MMC card for file storage and secure data applications. Preliminary DS41202C-page 123 PIC16F684 14.14 PICSTART Plus Development Programmer 14.17 PICDEM 2 Plus Demonstration Board The PICSTART Plus development programmer is an easy-to-use, low-cost, prototype programmer. It connects to the PC via a COM (RS-232) port. MPLAB Integrated Development Environment software makes using the programmer simple and efficient. The PICSTART Plus development programmer supports most PICmicro devices up to 40 pins. Larger pin count devices, such as the PIC16C92X and PIC17C76X, may be supported with an adapter socket. The PICSTART Plus development programmer is CE compliant. The PICDEM 2 Plus demonstration board supports many 18, 28 and 40-pin microcontrollers, including PIC16F87X and PIC18FXX2 devices. All the necessary hardware and software is included to run the demonstration programs. The sample microcontrollers provided with the PICDEM 2 demonstration board can be programmed with a PRO MATE II device programmer, PICSTART Plus development programmer, or MPLAB ICD 2 with a Universal Programmer Adapter. The MPLAB ICD 2 and MPLAB ICE in-circuit emulators may also be used with the PICDEM 2 demonstration board to test firmware. A prototype area extends the circuitry for additional application components. Some of the features include an RS-232 interface, a 2 x 16 LCD display, a piezo speaker, an on-board temperature sensor, four LEDs and sample PIC18F452 and PIC16F877 Flash microcontrollers. 14.15 PICDEM 1 PICmicro Demonstration Board The PICDEM 1 demonstration board demonstrates the capabilities of the PIC16C5X (PIC16C54 to PIC16C58A), PIC16C61, PIC16C62X, PIC16C71, PIC16C8X, PIC17C42, PIC17C43 and PIC17C44. All necessary hardware and software is included to run basic demo programs. The sample microcontrollers provided with the PICDEM 1 demonstration board can be programmed with a PRO MATE II device programmer or a PICSTART Plus development programmer. The PICDEM 1 demonstration board can be connected to the MPLAB ICE in-circuit emulator for testing. A prototype area extends the circuitry for additional application components. Features include an RS-232 interface, a potentiometer for simulated analog input, push button switches and eight LEDs. 14.16 PICDEM.net Internet/Ethernet Demonstration Board The PICDEM.net demonstration board is an Internet/ Ethernet demonstration board using the PIC18F452 microcontroller and TCP/IP firmware. The board supports any 40-pin DIP device that conforms to the standard pinout used by the PIC16F877 or PIC18C452. This kit features a user friendly TCP/IP stack, web server with HTML, a 24L256 Serial EEPROM for Xmodem download to web pages into Serial EEPROM, ICSP/MPLAB ICD 2 interface connector, an Ethernet interface, RS-232 interface and a 16 x 2 LCD display. Also included is the book and CD-ROM “TCP/IP Lean, Web Servers for Embedded Systems,” by Jeremy Bentham DS41202C-page 124 14.18 PICDEM 3 PIC16C92X Demonstration Board The PICDEM 3 demonstration board supports the PIC16C923 and PIC16C924 in the PLCC package. All the necessary hardware and software is included to run the demonstration programs. 14.19 PICDEM 4 8/14/18-Pin Demonstration Board The PICDEM 4 can be used to demonstrate the capabilities of the 8, 14 and 18-pin PIC16XXXX and PIC18XXXX MCUs, including the PIC16F818/819, PIC16F87/88, PIC16F62XA and the PIC18F1320 family of microcontrollers. PICDEM 4 is intended to showcase the many features of these low pin count parts, including LIN and Motor Control using ECCP. Special provisions are made for low-power operation with the supercapacitor circuit and jumpers allow onboard hardware to be disabled to eliminate current draw in this mode. Included on the demo board are provisions for Crystal, RC or Canned Oscillator modes, a five volt regulator for use with a nine volt wall adapter or battery, DB-9 RS-232 interface, ICD connector for programming via ICSP and development with MPLAB ICD 2, 2 x 16 liquid crystal display, PCB footprints for Hbridge motor driver, LIN transceiver and EEPROM. Also included are: header for expansion, eight LEDs, four potentiometers, three push buttons and a prototyping area. Included with the kit is a PIC16F627A and a PIC18F1320. Tutorial firmware is included along with the User’s Guide. Preliminary 2004 Microchip Technology Inc. PIC16F684 14.20 PICDEM 17 Demonstration Board The PICDEM 17 demonstration board is an evaluation board that demonstrates the capabilities of several Microchip microcontrollers, including PIC17C752, PIC17C756A, PIC17C762 and PIC17C766. A programmed sample is included. The PRO MATE II device programmer, or the PICSTART Plus development programmer, can be used to reprogram the device for user tailored application development. The PICDEM 17 demonstration board supports program download and execution from external on-board Flash memory. A generous prototype area is available for user hardware expansion. 14.21 PICDEM 18R PIC18C601/801 Demonstration Board The PICDEM 18R demonstration board serves to assist development of the PIC18C601/801 family of Microchip microcontrollers. It provides hardware implementation of both 8-bit Multiplexed/Demultiplexed and 16-bit Memory modes. The board includes 2 Mb external Flash memory and 128 Kb SRAM memory, as well as serial EEPROM, allowing access to the wide range of memory types supported by the PIC18C601/801. 14.22 PICDEM LIN PIC16C43X Demonstration Board The powerful LIN hardware and software kit includes a series of boards and three PICmicro microcontrollers. The small footprint PIC16C432 and PIC16C433 are used as slaves in the LIN communication and feature on-board LIN transceivers. A PIC16F874 Flash microcontroller serves as the master. All three microcontrollers are programmed with firmware to provide LIN bus communication. 14.24 PICDEM USB PIC16C7X5 Demonstration Board The PICDEM USB Demonstration Board shows off the capabilities of the PIC16C745 and PIC16C765 USB microcontrollers. This board provides the basis for future USB products. 14.25 Evaluation and Programming Tools In addition to the PICDEM series of circuits, Microchip has a line of evaluation kits and demonstration software for these products. • KEELOQ evaluation and programming tools for Microchip’s HCS Secure Data Products • CAN developers kit for automotive network applications • Analog design boards and filter design software • PowerSmart battery charging evaluation/ calibration kits • IrDA® development kit • microID development and rfLabTM development software • SEEVAL® designer kit for memory evaluation and endurance calculations • PICDEM MSC demo boards for Switching mode power supply, high-power IR driver, delta sigma ADC and flow rate sensor Check the Microchip web page and the latest Product Selector Guide for the complete list of demonstration and evaluation kits. 14.23 PICkitTM 1 Flash Starter Kit A complete “development system in a box”, the PICkit Flash Starter Kit includes a convenient multi-section board for programming, evaluation and development of 8/14-pin Flash PIC® microcontrollers. Powered via USB, the board operates under a simple Windows GUI. The PICkit 1 Starter Kit includes the User’s Guide (on CD ROM), PICkit 1 tutorial software and code for various applications. Also included are MPLAB® IDE (Integrated Development Environment) software, software and hardware “Tips ‘n Tricks for 8-pin Flash PIC® Microcontrollers” Handbook and a USB interface cable. Supports all current 8/14-pin Flash PIC microcontrollers, as well as many future planned devices. 2004 Microchip Technology Inc. Preliminary DS41202C-page 125 PIC16F684 NOTES: DS41202C-page 126 Preliminary 2004 Microchip Technology Inc. PIC16F684 15.0 ELECTRICAL SPECIFICATIONS Absolute Maximum Ratings(†) Ambient temperature under bias..........................................................................................................-40° to +125°C Storage temperature ........................................................................................................................ -65°C to +150°C Voltage on VDD with respect to VSS ................................................................................................... -0.3V to +6.5V Voltage on MCLR with respect to Vss ............................................................................................... -0.3V to +13.5V Voltage on all other pins with respect to VSS ........................................................................... -0.3V to (VDD + 0.3V) Total power dissipation(1) ............................................................................................................................... 800 mW Maximum current out of VSS pin ..................................................................................................................... 300 mA Maximum current into VDD pin ........................................................................................................................ 250 mA Input clamp current, IIK (VI < 0 or VI > VDD)...............................................................................................................± 20 mA Output clamp current, IOK (Vo < 0 or Vo >VDD).........................................................................................................± 20 mA Maximum output current sunk by any I/O pin.................................................................................................... 25 mA Maximum output current sourced by any I/O pin .............................................................................................. 25 mA Maximum current sunk by PORTA and PORTC (combined) .......................................................................... 200 mA Maximum current sourced PORTA and PORTC (combined) .......................................................................... 200 mA Note 1: Power dissipation is calculated as follows: PDIS = VDD x {IDD – ∑ IOH} + ∑ {(VDD – VOH) x IOH} + ∑(VOl x IOL). † NOTICE: 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 device 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. Note: Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up. Thus, a series resistor of 50-100 Ω should be used when applying a “low” level to the MCLR pin, rather than pulling this pin directly to VSS. 2004 Microchip Technology Inc. Preliminary DS41202C-page 127 PIC16F684 FIGURE 15-1: PIC16F684 VOLTAGE-FREQUENCY GRAPH, -40°C ≤ TA ≤ +125°C 5.5 5.0 4.5 VDD (Volts) 4.0 3.5 3.0 2.5 2.0 0 4 8 10 12 16 20 Frequency (MHz) Note 1: The shaded region indicates the permissible combinations of voltage and frequency. DS41202C-page 128 Preliminary 2004 Microchip Technology Inc. PIC16F684 15.1 DC Characteristics: PIC16F684 -I (Industrial) PIC16F684 -E (Extended) DC CHARACTERISTICS Param No. Sym VDD Characteristic Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +85°C for industrial -40°C ≤ TA ≤ +125°C for extended Min Typ† Max Units Conditions Supply Voltage D001 D001C D001D 2.0 3.0 4.5 — — — 5.5 5.5 5.5 V V V FOSC < = 4 MHz: FOSC < = 10 MHz FOSC < = 20 MHz 1.5* — — V Device in Sleep mode V See Section 12.3.3 “Power-On Reset (POR)” for details. D002 VDR RAM Data Retention Voltage(1) D003 VPOR VDD Start Voltage to ensure internal Power-on Reset signal — VSS — D004 SVDD VDD Rise Rate to ensure internal Power-on Reset signal 0.05* — — D005 VBOD Brown-out Detect — 2.1 — V/ms See Section 12.3.3 “Power-On Reset (POR)” for details. V * These parameters are characterized but not tested. † Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: This is the limit to which VDD can be lowered in Sleep mode without losing RAM data. 2004 Microchip Technology Inc. Preliminary DS41202C-page 129 PIC16F684 15.2 DC Characteristics: PIC16F684-I (Industrial) DC CHARACTERISTICS Param No. D010 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +85°C for industrial Conditions Device Characteristics Min Typ† Max Units VDD Supply Current (IDD)(1, 2) D011 D012 D013 D014 D015 D016 D017 D018 — 9 TBD µA 2.0 — 18 TBD µA 3.0 — 35 TBD µA 5.0 — 110 TBD µA 2.0 — 190 TBD µA 3.0 — 330 TBD µA 5.0 — 220 TBD µA 2.0 — 370 TBD µA 3.0 — 0.6 TBD mA 5.0 — 70 TBD µA 2.0 — 140 TBD µA 3.0 — 260 TBD µA 5.0 — 180 TBD µA 2.0 — 320 TBD µA 3.0 — 580 TBD µA 5.0 — TBD TBD µA 2.0 — TBD TBD µA 3.0 — TBD TBD mA 5.0 — 340 TBD µA 2.0 — 500 TBD µA 3.0 — 0.8 TBD mA 5.0 — 180 TBD µA 2.0 — 320 TBD µA 3.0 — 580 TBD µA 5.0 — 2.1 TBD mA 4.5 — 2.4 TBD mA 5.0 Note FOSC = 32 kHz LP Oscillator mode FOSC = 1 MHz XT Oscillator mode FOSC = 4 MHz XT Oscillator mode FOSC = 1 MHz EC Oscillator mode FOSC = 4 MHz EC Oscillator mode FOSC = 31 kHz INTRC mode FOSC = 4 MHz INTOSC mode FOSC = 4 MHz EXTRC mode FOSC = 20 MHz HS Oscillator mode Legend: TBD = To Be Determined. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from rail to rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled. 2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 3: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral ∆ current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. 4: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD. DS41202C-page 130 Preliminary 2004 Microchip Technology Inc. PIC16F684 15.2 DC Characteristics: PIC16F684-I (Industrial) (Continued) DC CHARACTERISTICS Param No. D020 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +85°C for industrial Conditions Device Characteristics Power-down Base Current(IPD)(4) D021 D022 D023 D024 D025 D026 Min Typ† Max Units VDD Note — 0.99 TBD nA 2.0 — 1.2 TBD nA 3.0 WDT, BOD, Comparators, VREF and T1OSC disabled — 2.9 TBD nA 5.0 — 0.3 TBD µA 2.0 — 1.8 TBD µA 3.0 — 8.4 TBD µA 5.0 — 58 TBD µA 3.0 — 109 TBD µA 5.0 — 3.3 TBD µA 2.0 — 6.1 TBD µA 3.0 — 11.5 TBD µA 5.0 — 58 TBD µA 2.0 — 85 TBD µA 3.0 — 138 TBD µA 5.0 — 4.0 TBD µA 2.0 — 4.6 TBD µA 3.0 — 6.0 TBD µA 5.0 — 1.2 TBD nA 3.0 — 0.0022 TBD µA 5.0 WDT Current BOD Current(2) Comparator Current(3) CVREF Current(1) T1OSC Current(1) A/D Current(1) Legend: TBD = To Be Determined. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from rail to rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled. 2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 3: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral ∆ current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. 4: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD. 2004 Microchip Technology Inc. Preliminary DS41202C-page 131 PIC16F684 15.3 DC Characteristics: PIC16F684-E (Extended) DC CHARACTERISTICS Param No. Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +125°C for extended Conditions Device Characteristics D010E Supply Current (IDD) D011E D012E D013E D014E D015E D016E D017E D018E Min Typ† Max Units VDD — 9 TBD µA 2.0 — 18 TBD µA 3.0 — 35 TBD µA 5.0 — 110 TBD µA 2.0 — 190 TBD µA 3.0 — 330 TBD µA 5.0 — 220 TBD µA 2.0 — 370 TBD µA 3.0 — 0.6 TBD mA 5.0 — 70 TBD µA 2.0 — 140 TBD µA 3.0 — 260 TBD µA 5.0 — 180 TBD µA 2.0 — 320 TBD µA 3.0 — 580 TBD µA 5.0 — TBD TBD µA 2.0 — TBD TBD µA 3.0 — TBD TBD mA 5.0 — 340 TBD µA 2.0 — 500 TBD µA 3.0 — 0.8 TBD mA 5.0 — 180 TBD µA 2.0 — 320 TBD µA 3.0 — 580 TBD µA 5.0 — 2.1 TBD mA 4.5 — 2.4 TBD mA 5.0 Note FOSC = 32 kHz LP Oscillator mode FOSC = 1 MHz XT Oscillator mode FOSC = 4 MHz XT Oscillator mode FOSC = 1 MHz EC Oscillator mode FOSC = 4 MHz EC Oscillator mode FOSC = 31 kHz INTRC mode FOSC = 4 MHz INTOSC mode FOSC = 4 MHz EXTRC mode FOSC = 20 MHz HS Oscillator mode Legend: TBD = To Be Determined. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from rail to rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled. 2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 3: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral ∆ current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. 4: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD. DS41202C-page 132 Preliminary 2004 Microchip Technology Inc. PIC16F684 15.3 DC Characteristics: PIC16F684-E (Extended) (Continued) DC CHARACTERISTICS Param No. Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +125°C for extended Conditions Device Characteristics Min Typ† Max Units VDD Note D020E Power-down Base Current (IPD)(4) — 0.00099 TBD µA 2.0 — 0.0012 TBD µA 3.0 WDT, BOD, Comparators, VREF and T1OSC disabled — 0.0029 TBD µA 5.0 D021E — 0.3 TBD µA 2.0 — 1.8 TBD µA 3.0 — 8.4 TBD µA 5.0 — 58 TBD µA 3.0 — 109 TBD µA 5.0 — 3.3 TBD µA 2.0 — 6.1 TBD µA 3.0 — 11.5 TBD µA 5.0 — 58 TBD µA 2.0 D022E D023E D024E D025E D026E — 85 TBD µA 3.0 — 138 TBD µA 5.0 — 4.0 TBD µA 2.0 — 4.6 TBD µA 3.0 — 6.0 TBD µA 5.0 — 0.0012 TBD µA 3.0 — 0.0022 TBD µA 5.0 WDT Current BOD Current Comparator Current(3) CVREF Current T1OSC Current A/D Current(3) Legend: TBD = To Be Determined. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from rail to rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled. 2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 3: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral ∆ current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. 4: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD. 2004 Microchip Technology Inc. Preliminary DS41202C-page 133 PIC16F684 15.4 DC Characteristics: PIC16F684 -I (Industrial) PIC16F684 -E (Extended) DC CHARACTERISTICS Param No. Sym VIL Characteristic Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +85°C for industrial -40°C ≤ TA ≤ +125°C for extended Min Typ† Max Units Conditions Vss — 0.8 V 4.5V ≤ VDD ≤ 5.5V Vss — 0.15 VDD V Otherwise Vss — 0.2 VDD V Entire range Input Low Voltage I/O port: D030 with TTL buffer D030A D031 with Schmitt Trigger buffer D032 MCLR, OSC1 (RC mode) VSS — 0.2 VDD V D033 OSC1 (XT and LP modes)(1) VSS — 0.3 V D033A OSC1 (HS mode)(1) VSS — 0.3 VDD V VIH Input High Voltage I/O ports: D040 D040A with TTL buffer D041 with Schmitt Trigger buffer — 2.0 (0.25 VDD + 0.8) — — VDD VDD V V 4.5V ≤ VDD ≤ 5.5V Otherwise 0.8 VDD — VDD V Entire range 0.8 VDD — VDD V D042 MCLR D043 OSC1 (XT and LP modes) 1.6 — VDD V (Note 1) D043A OSC1 (HS mode) 0.7 VDD — VDD V (Note 1) D043B OSC1 (RC mode) 0.9 VDD — VDD V 50* 250 400* µA VDD = 5.0V, VPIN = VSS — ± 0.1 ±1 µA VSS ≤ VPIN ≤ VDD, Pin at high-impedance D070 IPUR PORTA Weak Pull-up Current IIL Input Leakage Current(2) D060 I/O ports D061 MCLR(3) — ± 0.1 ±5 µA VSS ≤ VPIN ≤ VDD D063 OSC1 — ± 0.1 ±5 µA VSS ≤ VPIN ≤ VDD, XT, HS and LP oscillator configuration VOL Output Low Voltage D080 I/O ports — — 0.6 V IOL = 8.5 mA, VDD = 4.5V (Ind.) D083 OSC2/CLKOUT (RC mode) — — 0.6 V IOL = 1.6 mA, VDD = 4.5V (Ind.) IOL = 1.2 mA, VDD = 4.5V (Ext.) Legend: TBD = To Be Determined. * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external clock in RC mode. 2: Negative current is defined as current sourced by the pin. 3: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent normal operating conditions. Higher leakage current may be measured at different input voltages. 4: See Section 10.4.1 “Using the Data EEPROM” for additional information. DS41202C-page 134 Preliminary 2004 Microchip Technology Inc. PIC16F684 15.4 DC Characteristics: PIC16F684 -I (Industrial) PIC16F684 -E (Extended) (Continued) DC CHARACTERISTICS Param No. Sym VOH Characteristic Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +85°C for industrial -40°C ≤ TA ≤ +125°C for extended Min Typ† Max Units Conditions Output High Voltage D090 I/O ports VDD – 0.7 — — V IOH = -3.0 mA, VDD = 4.5V (Ind.) D092 OSC2/CLKOUT (RC mode) VDD – 0.7 — — V IOH = -1.3 mA, VDD = 4.5V (Ind.) IOH = -1.0 mA, VDD = 4.5V (Ext.) Ultra Low-Power Wake-up Current — 200 — nA — — 15* pF — — 50* pF D100 IULP Capacitive Loading Specs on Output Pins D100 COSC2 OSC2 pin D101 CIO All I/O pins In XT, HS and LP modes when external clock is used to drive OSC1 Data EEPROM Memory ED Byte Endurance 100K 1M — E/W -40°C ≤ TA ≤ +85°C D120A ED Byte Endurance 10K 100K — E/W +85°C ≤ TA ≤ +125°C D121 VDRW VDD for Read/Write VMIN — 5.5 V D122 TDEW Erase/Write Cycle Time — 5 6 ms D123 TRETD Characteristic Retention 40 — — Year Provided no other specifications are violated D124 TREF Number of Total Erase/Write Cycles before Refresh(4) 1M 10M — E/W -40°C ≤ TA ≤ +85°C D130 EP Cell Endurance 10K 100K — E/W -40°C ≤ TA ≤ +85°C D130A ED Cell Endurance 1K 10K — E/W +85°C ≤ TA ≤ +125°C D131 VPR VDD for Read VMIN — 5.5 D120 Using EECON1 to read/write VMIN = Minimum operating voltage Program Flash Memory V D132 VPEW VDD for Erase/Write 4.5 — 5.5 V D133 TPEW Erase/Write cycle time — 2 2.5 ms D134 TRETD Characteristic Retention 40 — — VMIN = Minimum operating voltage Year Provided no other specifications are violated Legend: TBD = To Be Determined. * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external clock in RC mode. 2: Negative current is defined as current sourced by the pin. 3: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent normal operating conditions. Higher leakage current may be measured at different input voltages. 4: See Section 10.4.1 “Using the Data EEPROM” for additional information. 2004 Microchip Technology Inc. Preliminary DS41202C-page 135 PIC16F684 15.5 Timing Parameter Symbology The timing parameter symbols have been created with one of the following formats: 1. TppS2ppS 2. TppS T F Frequency Lowercase letters (pp) and their meanings: pp cc CCP1 ck CLKOUT cs CS di SDI do SDO dt Data in io I/O port mc MCLR Uppercase letters and their meanings: S F Fall H High I Invalid (High-impedance) L Low FIGURE 15-2: T Time osc rd rw sc ss t0 t1 wr OSC1 RD RD or WR SCK SS T0CKI T1CKI WR P R V Z Period Rise Valid High-impedance LOAD CONDITIONS Load Condition 1 Load Condition 2 VDD/2 RL CL pin VSS VSS Legend: RL = 464Ω CL = 50 pF for all pins 15 pF for OSC2 output DS41202C-page 136 CL pin Preliminary 2004 Microchip Technology Inc. PIC16F684 15.6 AC Characteristics: PIC16F684 (Industrial, Extended) FIGURE 15-3: EXTERNAL CLOCK TIMING Q4 Q1 Q2 Q3 Q4 Q1 OSC1 1 3 4 3 4 2 CLKOUT TABLE 15-1: EXTERNAL CLOCK TIMING REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C ≤ TA ≤ +125°C Param No. Sym FOSC 1 2 3 TOSC TCY TosL, TosH Characteristic Min Typ† Max Units Conditions External CLKIN Frequency(1) DC DC DC DC — — — — 37 4 20 20 kHz MHz MHz MHz LP Oscillator mode XT Oscillator mode HS Oscillator mode EC Oscillator mode Oscillator Frequency(1) 5 — DC 0.1 1 — 4 — — — 37 — 4 4 20 kHz MHz MHz MHz MHz LP Oscillator mode INTOSC mode RC Oscillator mode XT Oscillator mode HS Oscillator mode External CLKIN Period(1) 27 50 50 250 — — — — ∞ ∞ ∞ ∞ µs ns ns ns LP Oscillator mode HS Oscillator mode EC Oscillator mode XT Oscillator mode Oscillator Period(1) 27 — 250 250 50 250 — — — 200 — — 10,000 1,000 µs ns ns ns ns LP Oscillator mode INTOSC mode RC Oscillator mode XT Oscillator mode HS Oscillator mode Instruction Cycle Time(1) External CLKIN (OSC1) High External CLKIN Low 200 TCY DC ns TCY = 4/FOSC 2* — — µs LP oscillator, TOSC L/H duty cycle 20* — — ns HS oscillator, TOSC L/H duty cycle 100 * — — ns XT oscillator, TOSC L/H duty cycle 4 TosR, External CLKIN Rise — — 50* ns LP oscillator TosF External CLKIN Fall — — 25* ns XT oscillator — — 15* ns HS oscillator * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are based on characterization data for that particular oscillator type under standard operating conditions with the device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at ‘min’ values with an external clock applied to OSC1 pin. When an external clock input is used, the ‘max’ cycle time limit is ‘DC’ (no clock) for all devices. 2004 Microchip Technology Inc. Preliminary DS41202C-page 137 PIC16F684 TABLE 15-2: PRECISION INTERNAL OSCILLATOR PARAMETERS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C ≤ TA ≤ +125°C Param No. F10 F14 Sym Characteristic Freq Tolerance Min Typ† Max Units ±1% — 8.00 TBD MHz VDD and Temperature TBD ±2% — 8.00 TBD MHz 2.5V ≤ VDD ≤ 5.5V 0°C ≤ TA ≤ +85°C ±5% — 8.00 TBD MHz 2.0V ≤ VDD ≤ 5.5V -40°C ≤ TA ≤ +85°C (Ind.) -40°C ≤ TA ≤ +125°C (Ext.) — — TBD TBD µs VDD = 2.0V, -40°C to +85°C — — TBD TBD µs VDD = 3.0V, -40°C to +85°C — — TBD TBD µs VDD = 5.0V, -40°C to +85°C FOSC Internal Calibrated INTOSC Frequency(1) TIOSC Oscillator Wake-up from ST Sleep Start-up Time* Conditions Legend: TBD = To Be Determined. * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as close to the device as possible. 0.1uF and 0.01uF values in parallel are recommended. FIGURE 15-4: CLKOUT AND I/O TIMING Q1 Q4 Q2 Q3 OSC1 11 10 22 23 CLKOUT 12 13 19 14 18 16 I/O pin (Input) 15 17 I/O pin (Output) New Value Old Value 20, 21 DS41202C-page 138 Preliminary 2004 Microchip Technology Inc. PIC16F684 TABLE 15-3: CLKOUT AND I/O TIMING REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C ≤ TA ≤ +125°C Param No. 10 Sym Characteristic Min Typ† Max Units Conditions TosH2ckL OSC1↑ to CLOUT↓ — 75 200 ns (Note 1) 11 TosH2ckH OSC1↑ to CLOUT↑ — 75 200 ns (Note 1) 12 TckR CLKOUT rise time — 35 100 ns (Note 1) 13 TckF CLKOUT fall time — 35 100 ns (Note 1) 14 TckL2ioV CLKOUT↓ to Port Out Valid — — 20 ns (Note 1) TOSC + 200 ns — — ns (Note 1) 0 — — ns (Note 1) 15 TioV2ckH Port In Valid before CLKOUT↑ 16 TckH2ioI Port In Hold after CLKOUT↑ 17 TosH2ioV OSC1↑ (Q1 cycle) to Port Out Valid OSC1↑ (Q2 cycle) to Port Input Invalid (I/O in hold time) — 50 150* ns — — 300 ns 100 — — ns 18 TosH2ioI 19 TioV2osH Port Input Valid to OSC1↑ (I/O in setup time) 0 — — ns 20 TioR Port Output Rise Time — 10 40 ns 21 TioF Port Output Fall Time — 10 40 ns 22 Tinp INT Pin High or Low Time 25 — — ns 23 Trbp PORTA Change INT High or Low Time TCY — — ns * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. Note 1: Measurements are taken in RC mode where CLKOUT output is 4 x TOSC. 2004 Microchip Technology Inc. Preliminary DS41202C-page 139 PIC16F684 FIGURE 15-5: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP TIMER TIMING VDD MCLR 30 Internal POR 33 PWRT Time-out 32 OSC Time-out Internal Reset Watchdog Timer Reset 34 31 34 I/O pins FIGURE 15-6: BROWN-OUT DETECT TIMING AND CHARACTERISTICS VDD VBOD (Device not in Brown-out Detect) (Device in Brown-out Detect) 35 Reset (due to BOD) Note 1: 64 ms Time-out(1) 64 ms delay only if PWRTE bit in the Configuration Word register is programmed to ‘0’. DS41202C-page 140 Preliminary 2004 Microchip Technology Inc. PIC16F684 TABLE 15-4: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER, AND BROWN-OUT DETECT REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C ≤ TA ≤ +125°C Param No. Sym Characteristic Min Typ† Max Units Conditions 30 TMCL MCLR Pulse Width (low) 2 11 — 18 — 24 µs ms VDD = 5V, -40°C to +85°C Extended temperature 31 TWDT Watchdog Timer Time-out Period (No Prescaler) 10 10 17 17 25 30 ms ms VDD = 5V, -40°C to +85°C Extended temperature 32 TOST Oscillation Start-up Timer Period — 1024TOSC — — TOSC = OSC1 period 33* TPWRT Power-up Timer Period 28* TBD 64 TBD 132* TBD ms ms VDD = 5V, -40°C to +85°C Extended Temperature 34 TIOZ I/O High-impedance from MCLR Low or Watchdog Timer Reset — — 2.0 µs VBOD Brown-out Detect Voltage 2.025 — 2.175 V TBOD Brown-out Detect Pulse Width 100* — — µs 35 VDD ≤ VBOD (D005) Legend: TBD = To Be Determined. * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. 2004 Microchip Technology Inc. Preliminary DS41202C-page 141 PIC16F684 FIGURE 15-7: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS T0CKI 40 41 42 T1CKI 45 46 48 47 TMR0 or TMR1 TABLE 15-5: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C ≤ TA ≤ +125°C Param No. Sym Characteristic 40* Tt0H T0CKI High Pulse Width 41* Tt0L T0CKI Low Pulse Width 42* Tt0P T0CKI Period 45* Tt1H T1CKI High Time 46* Tt1L T1CKI Low Time 47* 48 Tt1P T1CKI Input Period No Prescaler With Prescaler No Prescaler With Prescaler Synchronous, No Prescaler Synchronous, with Prescaler Asynchronous Synchronous, No Prescaler Synchronous, with Prescaler Asynchronous Synchronous Min Typ† Max Units Conditions 0.5 TCY + 20 10 0.5 TCY + 20 10 Greater of: 20 or TCY + 40 N 0.5 TCY + 20 15 — — — — — — — — — — ns ns ns ns ns — — — — ns ns 30 0.5 TCY + 20 15 — — — — — — ns ns ns 30 Greater of: 30 or TCY + 40 N 60 DC — — — — ns ns N = prescale value (2, 4, ..., 256) N = prescale value (1, 2, 4, 8) Asynchronous — — ns Ft1 Timer1 Oscillator Input Frequency Range — 200* kHz (oscillator enabled by setting bit T1OSCEN) TCKEZtmr1 Delay from External Clock Edge to Timer 2 TOSC* — 7 TOSC* — Increment * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. DS41202C-page 142 Preliminary 2004 Microchip Technology Inc. PIC16F684 FIGURE 15-8: CAPTURE/COMPARE/PWM TIMINGS (ECCP) CCP1 (Capture mode) 50 51 52 CCP1 (Compare or PWM mode) 53 Note: TABLE 15-6: 54 Refer to Figure 15-2 for load conditions. CAPTURE/COMPARE/PWM REQUIREMENTS (ECCP) Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C ≤ TA ≤ +125°C Param Symbol No. 50* TccL 51* TccH 52* TccP Characteristic CCP1 Input Low Time CCP1 Input High Time Min Typ† Max Units No Prescaler 0.5TCY + 20 — — ns With Prescaler 20 — — ns No Prescaler 0.5TCY + 20 — — ns With Prescaler 20 — — ns 3TCY + 40 N — — ns CCP1 Input Period 53* TccR CCP1 Output Rise Time — 25 50 ns 54* TccF CCP1 Output Fall Time — 25 45 ns Conditions N = prescale value (1, 4 or 16) * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. TABLE 15-7: COMPARATOR SPECIFICATIONS Comparator Specifications Sym Characteristics VOS Input Offset Voltage VCM Input Common Mode Voltage CMRR Common Mode Rejection Ratio TRT Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +125°C Min Typ Max Units — ± 5.0 ± 10 mV 0 — VDD – 1.5 V +55* — — db Response Time(1) — 150 400* ns TMC2COV Comparator Mode Change to Output Valid — — 10* µs * Note 1: Comments These parameters are characterized but not tested. Response time measured with one comparator input at (VDD – 1.5)/2 while the other input transitions from VSS to VDD – 1.5V. 2004 Microchip Technology Inc. Preliminary DS41202C-page 143 PIC16F684 TABLE 15-8: COMPARATOR VOLTAGE REFERENCE SPECIFICATIONS Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +125°C Voltage Reference Specifications Sym. Characteristics Min Typ Max Units Resolution — — VDD/24* VDD/32 — — LSb LSb Low Range (VRR = 1) High Range (VRR = 0) Absolute Accuracy — — — — ± 1/4* ± 1/2* LSb LSb Low Range (VRR = 1) High Range (VRR = 0) Unit Resistor Value (R) — 2K* — Ω — — 10* µs Settling Time * Note 1: (1) Comments These parameters are characterized but not tested. Settling time measured while VRR = 1 and VR<3:0> transitions from ‘0000’ to ‘1111’. TABLE 15-9: PIC16F684 A/D CONVERTER CHARACTERISTICS: Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +125°C Param No. Sym Characteristic Min Typ† Max Units bit Conditions A01 NR Resolution — — 10 bits A02 EABS Total Absolute Error*(1) — — ±1 LSb VREF = 5.0V A03 EIL Integral Error — — ±1 LSb VREF = 5.0V A04 EDL Differential Error — — ±1 LSb No missing codes to 10 bits VREF = 5.0V A05 EFS Full-scale Range 2.2* — 5.5* A06 EOFF Offset Error — — ±1 LSb VREF = 5.0V A07 EGN Gain Error — — ±1 LSb VREF = 5.0V (2) guaranteed V — — — VDD + 0.3 V VSS ≤ VAIN ≤ VREF+ A10 — Monotonicity — A20 A20A VREF Reference Voltage 2.2 2.5 — A25 VAIN Analog Input Voltage VSS — VREF V A30 ZAIN Recommended Impedance of Analog Voltage Source — — 10 kΩ A50 IREF VREF Input Current*(3) 10 — 1000 µA During VAIN acquisition. Based on differential of VHOLD to VAIN. — — 10 µA During A/D conversion cycle. Absolute minimum to ensure 10-bit accuracy * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: Total Absolute Error includes integral, differential, offset and gain errors. 2: The A/D conversion result never decreases with an increase in the input voltage and has no missing codes. 3: VREF current is from external VREF or VDD pin, whichever is selected as reference input. 4: When A/D is off, it will not consume any current other than leakage current. The power-down current specification includes any such leakage from the A/D module. DS41202C-page 144 Preliminary 2004 Microchip Technology Inc. PIC16F684 FIGURE 15-9: PIC16F684 A/D CONVERSION TIMING (NORMAL MODE) BSF ADCON0, GO 134 1 TCY (TOSC/2)(1) 131 Q4 130 A/D CLK 9 A/D Data 8 7 3 6 2 1 0 NEW_DATA OLD_DATA ADRES 1 TCY ADIF GO Sample Note 1: DONE Sampling Stopped 132 If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP instruction to be executed. TABLE 15-10: PIC16F684 A/D CONVERSION REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +125°C Param No. Sym Characteristic 130 TAD A/D Clock Period 130 TAD A/D Internal RC Oscillator Period 131 TCNV Conversion Time (not including Acquisition Time)(1) 132 TACQ Acquisition Time 134 TGO Q4 to A/D Clock Start Min Typ† Max Units Conditions 1.6 — — µs 3.0* — — µs TOSC-based, VREF full range TOSC-based, VREF ≥ 3.0V 3.0* 6.0 9.0* µs ADCS<1:0> = 11 (RC mode) At VDD = 2.5V 2.0* 4.0 6.0* µs At VDD = 5.0V — 11 — TAD Set GO bit to new data in A/D Result register 11.5 — µs 5* — — µs The minimum time is the amplifier settling time. This may be used if the “new” input voltage has not changed by more than 1 LSb (i.e., 4.1 mV @ 4.096V) from the last sampled voltage (as stored on CHOLD). — TOSC/2 — — If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP instruction to be executed. * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: ADRESH and ADRESL registers may be read on the following TCY cycle. 2: See Table 9-1 for minimum conditions. 2004 Microchip Technology Inc. Preliminary DS41202C-page 145 PIC16F684 FIGURE 15-10: PIC16F684 A/D CONVERSION TIMING (SLEEP MODE) BSF ADCON0, GO 134 (TOSC/2 + TCY)(1) 1 TCY 131 Q4 130 A/D CLK 9 A/D Data 8 7 6 3 2 1 NEW_DATA OLD_DATA ADRES 0 ADIF 1 TCY GO DONE Note 1: Sampling Stopped 132 Sample If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP instruction to be executed. TABLE 15-11: PIC16F684 A/D CONVERSION REQUIREMENTS (SLEEP MODE) Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C ≤ TA ≤ +125°C Param No. 130 Sym TAD Characteristic A/D Internal RC Oscillator Period Min Typ† Max Units Conditions 3.0* 6.0 9.0* µs ADCS<1:0> = 11 (RC mode) At VDD = 2.5V At VDD = 5.0V 2.0* 4.0 6.0* µs 131 TCNV Conversion Time (not including Acquisition Time)(1) — 11 — TAD 132 TACQ Acquisition Time (2) 11.5 — µs 5* — — µs The minimum time is the amplifier settling time. This may be used if the “new” input voltage has not changed by more than 1 LSb (i.e., 4.1 mV @ 4.096V) from the last sampled voltage (as stored on CHOLD). — TOSC/2 + TCY — — If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP instruction to be executed. 134 TGO Q4 to A/D Clock Start * These parameters are characterized but not tested. † Data in ‘Typ’ column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: ADRES register may be read on the following TCY cycle. 2: See Table 9-1 for minimum conditions. DS41202C-page 146 Preliminary 2004 Microchip Technology Inc. PIC16F684 16.0 DC AND AC CHARACTERISTICS GRAPHS AND TABLES Graphs are not available at this time. 2004 Microchip Technology Inc. Preliminary DS41202C-page 147 PIC16F684 NOTES: DS41202C-page 148 Preliminary 2004 Microchip Technology Inc. PIC16F684 17.0 PACKAGING INFORMATION 17.1 Package Marking Information Example 14-Lead PDIP (Skinny DIP) 16F684-I XXXXXXXXXXXXXX XXXXXXXXXXXXXX YYWWNNN 0415017 14-Lead SOIC Example 16F684-E XXXXXXXXXXX XXXXXXXXXXX YYWWNNN 0415017 Example 14-Lead TSSOP XXXXXXXX 16F684 YYWW 0415 NNN 017 Legend: XX...X Y YY WW NNN Note: * Customer specific information* Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week ‘01’) Alphanumeric traceability code In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line thus limiting the number of available characters for customer specific information. Standard PICmicro device marking consists of Microchip part number, year code, week code, and traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP price. 2004 Microchip Technology Inc. Preliminary DS41202C-page 149 PIC16F684 17.2 Package Details The following sections give the technical details of the packages. 14-Lead Plastic Dual In-line (P) – 300 mil (PDIP) E1 D 2 n 1 α E A2 A L c A1 β B1 eB p B Units Dimension Limits n p MIN INCHES* NOM 14 .100 .155 .130 MAX MILLIMETERS NOM 14 2.54 3.56 3.94 2.92 3.30 0.38 7.62 7.94 6.10 6.35 18.80 19.05 3.18 3.30 0.20 0.29 1.14 1.46 0.36 0.46 7.87 9.40 5 10 5 10 MIN Number of Pins Pitch Top to Seating Plane A .140 .170 Molded Package Thickness A2 .115 .145 Base to Seating Plane A1 .015 Shoulder to Shoulder Width E .300 .313 .325 Molded Package Width .240 .250 .260 E1 Overall Length D .740 .750 .760 Tip to Seating Plane L .125 .130 .135 c Lead Thickness .008 .012 .015 Upper Lead Width B1 .045 .058 .070 Lower Lead Width B .014 .018 .022 Overall Row Spacing § eB .310 .370 .430 α Mold Draft Angle Top 5 10 15 β Mold Draft Angle Bottom 5 10 15 * Controlling Parameter § Significant Characteristic Notes: Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010” (0.254mm) per side. JEDEC Equivalent: MS-001 Drawing No. C04-005 DS41202C-page 150 Preliminary MAX 4.32 3.68 8.26 6.60 19.30 3.43 0.38 1.78 0.56 10.92 15 15 2004 Microchip Technology Inc. PIC16F684 14-Lead Plastic Small Outline (SL) – Narrow, 150 mil (SOIC) E E1 p D 2 B n 1 α h 45° c A2 A φ A1 L β Units Dimension Limits n p Number of Pins Pitch Overall Height Molded Package Thickness Standoff § Overall Width Molded Package Width Overall Length Chamfer Distance Foot Length Foot Angle Lead Thickness Lead Width Mold Draft Angle Top Mold Draft Angle Bottom * Controlling Parameter § Significant Characteristic A A2 A1 E E1 D h L φ c B α β MIN .053 .052 .004 .228 .150 .337 .010 .016 0 .008 .014 0 0 INCHES* NOM 14 .050 .061 .056 .007 .236 .154 .342 .015 .033 4 .009 .017 12 12 MAX .069 .061 .010 .244 .157 .347 .020 .050 8 .010 .020 15 15 MILLIMETERS NOM 14 1.27 1.35 1.55 1.32 1.42 0.10 0.18 5.79 5.99 3.81 3.90 8.56 8.69 0.25 0.38 0.41 0.84 0 4 0.20 0.23 0.36 0.42 0 12 0 12 MIN MAX 1.75 1.55 0.25 6.20 3.99 8.81 0.51 1.27 8 0.25 0.51 15 15 Notes: Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .010” (0.254mm) per side. JEDEC Equivalent: MS-012 Drawing No. C04-065 2004 Microchip Technology Inc. Preliminary DS41202C-page 151 PIC16F684 14-Lead Plastic Thin Shrink Small Outline (ST) – 4.4 mm (TSSOP) E E1 p D 2 1 n B α A c φ β A1 L Units Dimension Limits n p Number of Pins Pitch Overall Height Molded Package Thickness Standoff § Overall Width Molded Package Width Molded Package Length Foot Length Foot Angle Lead Thickness Lead Width Mold Draft Angle Top Mold Draft Angle Bottom * Controlling Parameter § Significant Characteristic A A2 A1 E E1 D L φ c B α β MIN .033 .002 .246 .169 .193 .020 0 .004 .007 0 0 INCHES NOM 14 .026 .035 .004 .251 .173 .197 .024 4 .006 .010 5 5 A2 MAX .043 .037 .006 .256 .177 .201 .028 8 .008 .012 10 10 MILLIMETERS* NOM MAX 14 0.65 1.10 0.85 0.90 0.95 0.05 0.10 0.15 6.25 6.38 6.50 4.30 4.40 4.50 4.90 5.00 5.10 0.50 0.60 0.70 0 4 8 0.09 0.15 0.20 0.19 0.25 0.30 0 5 10 0 5 10 MIN Notes: Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .005” (0.127mm) per side. JEDEC Equivalent: MO-153 Drawing No. C04-087 DS41202C-page 152 Preliminary 2004 Microchip Technology Inc. PIC16F684 APPENDIX A: DATA SHEET REVISION HISTORY APPENDIX B: Revision A MIGRATING FROM OTHER PICmicro® DEVICES This discusses some of the issues in migrating from other PICmicro devices to the PIC16F6XX Family of devices. This is a new data sheet. Revision B Rewrites of the Oscillator and Special Features of the CPU Sections. General corrections to Figures and formatting. B.1 PIC16F676 to PIC16F684 TABLE B-1: FEATURE COMPARISON Feature PIC16F676 PIC16F684 Max Operating Speed 20 MHz 20 MHz 1024 2048 Max Program Memory (Words) SRAM (bytes) 64 128 A/D Resolution 10-bit 10-bit Data EEPROM (Bytes) 128 256 Timers (8/16-bit) 1/1 2/1 Oscillator Modes 8 8 Brown-out Detect Y Y Internal Pull-ups RA0/1/2/4/5 RA0/1/2/4/5, MCLR Interrupt-on-change 1 2 ECCP N Y Ultra Low-Power Wake-up N Y Extended WDT N Y Software Control Option of WDT/BOD N Y INTOSC Frequencies 4 MHz 32 kHz8 MHz N Y Clock Switching Note: 2004 Microchip Technology Inc. RA0/1/2/3/4/5 RA0/1/2/3/4/5 Comparator Preliminary This device has been designed to perform to the parameters of its data sheet. It has been tested to an electrical specification designed to determine its conformance with these parameters. Due to process differences in the manufacture of this device, this device may have different performance characteristics than its earlier version. These differences may cause this device to perform differently in your application than the earlier version of this device. DS41202C-page 153 PIC16F684 NOTES: DS41202C-page 154 Preliminary 2004 Microchip Technology Inc. PIC16F684 INDEX A A/D ...................................................................................... 63 Acquisition Requirements ........................................... 68 Analog Port Pins ......................................................... 63 Associated Registers .................................................. 70 Block Diagram............................................................. 63 Calculating Acquisition Time....................................... 68 Channel Selection....................................................... 63 Configuration and Operation....................................... 63 Configuring.................................................................. 67 Configuring Interrupt ................................................... 67 Conversion Clock........................................................ 64 Effects of a Reset........................................................ 69 Internal Sampling Switch (RSS) Impedance................ 68 Operation During Sleep .............................................. 69 Output Format............................................................. 65 Reference Voltage (VREF)........................................... 63 Source Impedance...................................................... 68 Special Event Trigger.................................................. 69 Specifications............................................ 144, 145, 146 Starting a Conversion ................................................. 64 Using the ECCP Trigger ............................................. 69 Absolute Maximum Ratings .............................................. 127 AC Characteristics Industrial and Extended ............................................ 137 Load Conditions ........................................................ 136 ADCON0 Register............................................................... 66 ADCON1 Register............................................................... 66 Analog Front-end (AFE) Power-On Reset ......................................................... 95 Analog Input Connection Considerations............................ 56 Analog-to-Digital Converter. See A/D ANSEL Register .................................................................. 65 Assembler MPASM Assembler................................................... 121 B Block Diagrams A/D .............................................................................. 63 Analog Input Model ............................................... 56, 68 Capture Mode Operation ............................................ 76 Comparator 1 .............................................................. 58 Comparator 2 .............................................................. 58 Comparator Modes ..................................................... 57 Comparator Voltage Reference (CVREF) .................... 60 Compare ..................................................................... 77 Fail-Safe Clock Monitor (FSCM) ................................. 27 In-Circuit Serial Programming Connections.............. 109 Interrupt Logic ........................................................... 102 MCLR Circuit............................................................... 95 On-Chip Reset Circuit ................................................. 94 PIC16F684.................................................................... 5 PWM (Enhanced)........................................................ 78 RA0 Pins ..................................................................... 35 RA1 Pins ..................................................................... 36 RA2 Pin....................................................................... 37 RA3 Pin....................................................................... 37 RA4 Pin....................................................................... 38 RA5 Pin....................................................................... 38 RC0 and RC1 Pins...................................................... 40 RC2 and RC3 Pins...................................................... 41 RC4 Pin....................................................................... 41 RC5 Pin....................................................................... 42 Resonator Operation................................................... 21 2004 Microchip Technology Inc. System Clock.............................................................. 19 Timer1 ........................................................................ 49 Timer2 ........................................................................ 54 TMR0/WDT Prescaler ................................................ 45 Watchdog Timer (WDT)............................................ 105 Brown-out Detect (BOD)..................................................... 96 Associated .................................................................. 97 Calibration .................................................................. 96 Specifications ........................................................... 141 Timing and Characteristics ....................................... 140 C C Compilers MPLAB C17.............................................................. 122 MPLAB C18.............................................................. 122 MPLAB C30.............................................................. 122 CALIB Register ................................................................... 93 Calibration Bits.................................................................... 93 Capture Module. See Enhanced Capture/Compare/PWM (ECCP) CCP1CON Register............................................................ 75 CCPR1H Register............................................................... 75 CCPR1L Register ............................................................... 75 CMCON0 Register.............................................................. 55 CMCON1 Register.............................................................. 59 Code Examples Assigning Prescaler to Timer0.................................... 47 Assigning Prescaler to WDT....................................... 47 Changing Between Capture Prescalers ..................... 76 Data EEPROM Read.................................................. 73 Data EEPROM Write .................................................. 73 Indirect Addressing..................................................... 17 Initializing A/D............................................................. 67 Initializing PORTA ...................................................... 31 Initializing PORTC ...................................................... 40 Saving Status and W Registers in RAM ................... 104 Ultra Low-Power Wake-up Initialization...................... 34 Write Verify ................................................................. 73 Code Protection ................................................................ 108 Comparator Voltage Reference (CVREF)............................ 60 Accuracy/Error............................................................ 60 Associated registers ................................................... 62 Configuring ................................................................. 60 Effects of a Reset ....................................................... 61 Response Time .......................................................... 61 Specifications ........................................................... 144 Comparators ....................................................................... 55 Associated Registers.................................................. 62 C2OUT as T1 Gate............................................... 50, 59 Configurations ............................................................ 57 Effects of a Reset ....................................................... 61 Interrupts .................................................................... 59 Operation.................................................................... 56 Operation During Sleep .............................................. 61 Outputs ....................................................................... 59 Response Time .......................................................... 61 Specifications ........................................................... 143 Synchronizing C2OUT w/ Timer1 ............................... 59 Compare Module. See Enhanced Capture/Compare/PWM (ECCP) CONFIG Register ............................................................... 92 Configuration Bits ............................................................... 92 CPU Features ..................................................................... 91 Preliminary DS41202C-page 155 PIC16F684 D Data EEPROM Memory Associated Registers .................................................. 74 Code Protection .................................................... 71, 74 Data Memory......................................................................... 7 DC Characteristics Extended and Industrial ............................................ 134 Industrial and Extended ............................................ 129 Demonstration Boards PICDEM 1 ................................................................. 124 PICDEM 17 ............................................................... 125 PICDEM 18R ............................................................ 125 PICDEM 2 Plus ......................................................... 124 PICDEM 3 ................................................................. 124 PICDEM 4 ................................................................. 124 PICDEM LIN ............................................................. 125 PICDEM USB............................................................ 125 PICDEM.net Internet/Ethernet .................................. 124 Development Support ....................................................... 121 Device Overview ................................................................... 5 E ECCP. See Enhanced Capture/Compare/PWM (ECCP) ECCPAS Register ............................................................... 86 EEADR Register ................................................................. 71 EECON1 Register ............................................................... 72 EECON2 Register ............................................................... 72 EEDAT Register.................................................................. 71 EEPROM Data Memory Avoiding Spurious Write.............................................. 74 Reading....................................................................... 73 Write Verify ................................................................. 73 Writing ......................................................................... 73 Electrical Specifications .................................................... 127 Enhanced Capture/Compare/PWM (ECCP) ....................... 75 Associated registers.................................................... 89 Associated registers w/ Capture/Compare/Timer1 ..... 77 Capture Mode ............................................................. 76 Prescaler............................................................. 76 CCP1 Pin Configuration .............................................. 76 Compare Mode ........................................................... 77 CCP1 Pin Configuration...................................... 77 Software Interrupt Mode ..................................... 77 Special Event Trigger and A/D Conversions....... 77 Special Trigger Output ........................................ 77 Timer1 Mode Selection ....................................... 77 Enhanced PWM Mode ................................................ 78 Auto-restart ......................................................... 87 Auto-shutdown .............................................. 85, 87 Direction Change in Full-Bridge Output Mode .... 83 Duty Cycle........................................................... 79 Effects of Reset................................................... 88 Example PWM Frequencies and Resolutions..... 79 Full-Bridge Application Example ......................... 83 Full-Bridge Mode................................................. 82 Half-Bridge Application Examples....................... 81 Half-Bridge Mode ................................................ 81 Operation in Power Managed Modes ................. 88 Operation with Fail-Safe Clock Monitor .............. 88 Output Configurations ......................................... 78 Output Relationships (Active-High and Active-Low) 80 Output Relationships Diagram ............................ 80 Period.................................................................. 79 Programmable Dead Band Delay ....................... 85 DS41202C-page 156 Setup for Operation ............................................ 88 Shoot-through Current ........................................ 85 Start-up Considerations ...................................... 87 TMR2 to PR2 Match ........................................... 53 Specifications ........................................................... 143 Timer Resources ........................................................ 75 Errata .................................................................................... 3 Evaluation and Programming Tools.................................. 125 F Fail-Safe Clock Monitor ...................................................... 27 Fail-Safe Mode ........................................................... 27 Reset and Wake-up from Sleep.................................. 28 Firmware Instructions ....................................................... 111 Fuses. See Configuration Bits G General Purpose Register File ............................................. 8 I ID Locations...................................................................... 108 In-Circuit Debugger........................................................... 109 In-Circuit Serial Programming (ICSP)............................... 108 Indirect Addressing, INDF and FSR registers..................... 17 Instruction Format............................................................. 111 Instruction Set................................................................... 111 ADDLW..................................................................... 113 ADDWF..................................................................... 113 ANDLW..................................................................... 113 ANDWF..................................................................... 113 BCF .......................................................................... 113 BSF........................................................................... 113 BTFSC ...................................................................... 113 BTFSS ...................................................................... 114 CALL......................................................................... 114 CLRF ........................................................................ 114 CLRW ....................................................................... 114 CLRWDT .................................................................. 114 COMF ....................................................................... 114 DECF ........................................................................ 114 DECFSZ ................................................................... 115 GOTO ....................................................................... 115 INCF ......................................................................... 115 INCFSZ..................................................................... 115 IORLW ...................................................................... 115 IORWF...................................................................... 115 MOVF ....................................................................... 116 MOVLW .................................................................... 116 MOVWF .................................................................... 116 NOP .......................................................................... 116 RETFIE ..................................................................... 117 RETLW ..................................................................... 117 RETURN................................................................... 117 RLF ........................................................................... 118 RRF .......................................................................... 118 SLEEP ...................................................................... 118 SUBLW ..................................................................... 118 SUBWF..................................................................... 119 SWAPF ..................................................................... 119 XORLW .................................................................... 119 XORWF .................................................................... 119 Summary Table ........................................................ 112 INTCON Register................................................................ 13 Internal Oscillator Block INTOSC Specifications ................................................... 138 Preliminary 2004 Microchip Technology Inc. PIC16F684 Internal Sampling Switch (RSS) Impedance ........................ 68 Interrupts ........................................................................... 101 A/D .............................................................................. 67 Associated Registers ................................................ 103 Capture ....................................................................... 76 Comparators ............................................................... 59 Compare ..................................................................... 77 Context Saving.......................................................... 104 Data EEPROM Memory Write .................................... 72 Interrupt-on-Change.................................................... 33 PORTA Interrupt-on-Change .................................... 102 RA2/INT .................................................................... 101 TMR0 ........................................................................ 102 TMR1 .......................................................................... 50 TMR2 to PR2 Match ................................................... 54 TMR2 to PR2 Match (PWM) ....................................... 53 INTOSC Specifications ..................................................... 138 IOCA Register ..................................................................... 33 L Load Conditions ................................................................ 136 M MCLR .................................................................................. 95 Internal ........................................................................ 95 Memory Organization............................................................ 7 Data .............................................................................. 7 Data EEPROM Memory.............................................. 71 Program ........................................................................ 7 Migrating from other PICmicro Devices ............................ 153 MPLAB ASM30 Assembler, Linker, Librarian ................... 122 MPLAB ICD 2 In-Circuit Debugger ................................... 123 MPLAB ICE 2000 High-Performance Universal In-Circuit Emulator ................................................... 123 MPLAB ICE 4000 High-Performance Universal In-Circuit Emulator ................................................... 123 MPLAB Integrated Development Environment Software .. 121 MPLAB PM3 Device Programmer .................................... 123 MPLINK Object Linker/MPLIB Object Librarian ................ 122 O OPCODE Field Descriptions ............................................. 111 OPTION_REG Register ...................................................... 12 OSCCON Register .............................................................. 29 Oscillator Associated registers.................................................... 29 Oscillator Configurations ..................................................... 19 Oscillator Specifications .................................................... 137 Oscillator Start-up Timer (OST) Specifications............................................................ 141 Oscillator Switching Fail-Safe Clock Monitor............................................... 27 Two-Speed Clock Start-up.......................................... 25 P P1A/P1B/P1C/P1D.See Enhanced Capture/Compare/PWM (ECCP) ................................ 78 Packaging ......................................................................... 149 Marking ..................................................................... 149 PDIP Details.............................................................. 150 PCL and PCLATH ............................................................... 17 Computed GOTO........................................................ 17 Stack ........................................................................... 17 PCON Register ................................................................... 97 PICkit 1 Flash Starter Kit................................................... 125 PICSTART Plus Development Programmer ..................... 124 2004 Microchip Technology Inc. PIE1 Register ..................................................................... 14 Pin Diagram .......................................................................... 2 Pinout Descriptions PIC16F684 ................................................................... 6 PIR1 Register ..................................................................... 15 PORTA ............................................................................... 31 Additional Pin Functions ............................................. 31 Interrupt-on-Change ........................................... 33 Ultra Low-Power Wake-up............................ 31, 34 Weak Pull-up ...................................................... 31 Associated registers ................................................... 39 Pin Descriptions and Diagrams .................................. 36 RA0............................................................................. 36 RA1............................................................................. 36 RA2............................................................................. 37 RA3............................................................................. 37 RA4............................................................................. 38 RA5............................................................................. 38 Specifications ........................................................... 139 PORTC ............................................................................... 40 Associated Registers.................................................. 29 Associated registers ................................................... 43 P1A/P1B/P1C/P1D.See Enhanced Capture/Compare/PWM (ECCP)........................ 40 Specifications ........................................................... 139 Power-Down Mode (Sleep)............................................... 107 Power-on Reset (POR)....................................................... 95 Power-up Timer (PWRT) .................................................... 96 Specifications ........................................................... 141 Precision Internal Oscillator Parameters .......................... 138 Prescaler Shared WDT/Timer0................................................... 47 Switching Prescaler Assignment ................................ 47 PRO MATE II Universal Device Programmer ................... 123 Product Identification ........................................................ 161 Program Memory .................................................................. 7 Map and Stack.............................................................. 7 Programming, Device Instructions.................................... 111 PWM Mode. See Enhanced Capture/Compare/PWM ........ 78 PWM1CON Register........................................................... 85 R Read-Modify-Write Operations ......................................... 111 Registers ADCON0 (A/D Control 0)............................................ 66 ADCON1 (A/D Control 1)............................................ 66 ANSEL (Analog Select) .............................................. 65 CALIB (Calibration Word) ........................................... 93 CCP1CON (Enhanced CCP Operation) ..................... 75 CCPR1H..................................................................... 75 CCPR1L ..................................................................... 75 CMCON0 (Comparator Control 0) .............................. 55 CMCON1 (Comparator Control 1) .............................. 59 CONFIG (Configuration Word) ................................... 92 Data Memory Map ........................................................ 8 ECCPAS (Enhanced CCP Auto-shutdown Control) ... 86 EEADR (EEPROM Address) ...................................... 71 EECON1 (EEPROM Control 1) .................................. 72 EECON2 (EEPROM Control 2) .................................. 72 EEDAT (EEPROM Data) ............................................ 71 INTCON (Interrupt Control) ........................................ 13 IOCA (Interrupt-on-change PORTA) .......................... 33 OPTION_REG ............................................................ 46 OPTION_REG (Option) .............................................. 12 OSCCON (Oscillator Control)..................................... 29 PCON (Power Control) ............................................... 97 Preliminary DS41202C-page 157 PIC16F684 PIE1 (Peripheral Interrupt Enable 1) ........................... 14 PIR1 (Peripheral Interrupt Register 1) ........................ 15 PORTA........................................................................ 31 PORTC ....................................................................... 43 PWM1CON (Enhanced PWM Configuration) ............. 85 Reset Values............................................................... 99 Reset Values (special registers) ............................... 100 Special Function Registers ........................................... 8 Special Register Summary ......................................... 10 Status .......................................................................... 11 T1CON (Timer1 Control)............................................. 51 T2CON (Timer2 Control)............................................. 53 TRISA (Tri-state PORTA) ........................................... 32 TRISC (Tri-state PORTC) ........................................... 43 VRCON (Voltage Reference Control) ......................... 62 WDTCON (Watchdog Timer Control)........................ 106 WPUA (Weak Pull-up PORTA) ................................... 32 Reset................................................................................... 94 Revision History ................................................................ 153 S Shoot-through Current ........................................................ 85 Software Simulator (MPLAB SIM)..................................... 122 Software Simulator (MPLAB SIM30)................................. 122 Special Event Trigger.......................................................... 69 Special Function Registers ................................................... 8 Status Register.................................................................... 11 T Time-out Sequence............................................................. 97 Timer0 ................................................................................. 45 Associated Registers .................................................. 47 External Clock ............................................................. 46 Interrupt....................................................................... 45 Operation .................................................................... 45 Specifications ............................................................ 142 T0CKI .......................................................................... 46 Timer1 ................................................................................. 49 Associated registers.................................................... 52 Asynchronous Counter Mode ..................................... 52 Reading and Writing ........................................... 52 Interrupt....................................................................... 50 Modes of Operations................................................... 50 Operation During Sleep .............................................. 52 Oscillator ..................................................................... 52 Prescaler ..................................................................... 50 Specifications ............................................................ 142 Timer1 Gate Inverting Gate ..................................................... 50 Selecting Source........................................... 50, 59 Synchronizing C2OUT w/ Timer1 ....................... 59 TMR1H Register ......................................................... 49 TMR1L Register .......................................................... 49 Timer2 ................................................................................. 53 Associated Registers .................................................. 54 Operation .................................................................... 53 Postscaler ................................................................... 53 PR2 Register............................................................... 53 Prescaler ..................................................................... 53 TMR2 Register ............................................................ 53 TMR2 to PR2 Match Interrupt ............................... 53, 54 Timing Diagrams A/D Conversion ......................................................... 145 A/D Conversion (Sleep Mode) .................................. 146 Brown-out Detect (BOD) ........................................... 140 Brown-out Detect Situations ....................................... 96 DS41202C-page 158 CLKOUT and I/O ...................................................... 138 Comparator Output ..................................................... 56 Enhanced Capture/Compare/PWM (ECCP)............. 143 External Clock........................................................... 137 Fail-Safe Clock Monitor (FSCM)................................. 28 Full-Bridge PWM Output............................................. 82 Half-Bridge PWM Output ............................................ 81 INT Pin Interrupt ....................................................... 103 PWM Auto-shutdown Auto-restart Disabled.......................................... 87 Auto-restart Enabled........................................... 87 PWM Direction Change .............................................. 84 PWM Direction Change at Near 100% Duty Cycle..... 84 PWM Output (Active-High) ......................................... 80 PWM Output (Active-Low) .......................................... 80 Reset, WDT, OST and Power-up Timer ................... 140 Time-out Sequence Case 1 ................................................................ 98 Case 2 ................................................................ 98 Case 3 ................................................................ 98 Timer0 and Timer1 External Clock ........................... 142 Timer1 Incrementing Edge ......................................... 50 Two Speed Start-up.................................................... 26 Wake-up from Interrupt............................................. 108 Timing Parameter Symbology .......................................... 136 TRISA Register................................................................... 32 TRISC Register................................................................... 43 Two-Speed Clock Start-up Mode........................................ 25 U Ultra Low-Power Wake-up............................................ 31, 34 Ultra Low-power Wake-up .................................................... 6 V Voltage Reference. See Comparator Voltage Reference (CVREF) VRCON Register ................................................................ 62 VREF. SEE A/D Reference Voltage W Wake-up Using Interrupts ................................................. 107 Watchdog Timer (WDT).................................................... 105 Associated registers ................................................. 106 Clock Source ............................................................ 105 Modes ....................................................................... 105 Period ....................................................................... 105 Specifications ........................................................... 141 WDTCON Register ........................................................... 106 WPUA Register................................................................... 32 WWW, On-Line Support ....................................................... 3 Preliminary 2004 Microchip Technology Inc. PIC16F684 ON-LINE SUPPORT Microchip provides on-line support on the Microchip World Wide Web site. The web site is used by Microchip as a means to make files and information easily available to customers. To view the site, the user must have access to the Internet and a web browser, such as Netscape® or Microsoft® Internet Explorer. Files are also available for FTP download from our FTP site. SYSTEMS INFORMATION AND UPGRADE HOT LINE The Systems Information and Upgrade Line provides system users a listing of the latest versions of all of Microchip’s development systems software products. Plus, this line provides information on how customers can receive the most current upgrade kits. The Hot Line Numbers are: 1-800-755-2345 for U.S. and most of Canada, and 1-480-792-7302 for the rest of the world. Connecting to the Microchip Internet Web Site 042003 The Microchip web site is available at the following URL: www.microchip.com The file transfer site is available by using an FTP service to connect to: ftp://ftp.microchip.com The web site and file transfer site provide a variety of services. Users may download files for the latest Development Tools, Data Sheets, Application Notes, User’s Guides, Articles and Sample Programs. A variety of Microchip specific business information is also available, including listings of Microchip sales offices, distributors and factory representatives. Other data available for consideration is: • Latest Microchip Press Releases • Technical Support Section with Frequently Asked Questions • Design Tips • Device Errata • Job Postings • Microchip Consultant Program Member Listing • Links to other useful web sites related to Microchip Products • Conferences for products, Development Systems, technical information and more • Listing of seminars and events 2004 Microchip Technology Inc. Preliminary DS41202C-page 159 PIC16F684 READER RESPONSE It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150. Please list the following information, and use this outline to provide us with your comments about this document. To: Technical Publications Manager RE: Reader Response Total Pages Sent ________ From: Name Company Address City / State / ZIP / Country Telephone: (_______) _________ - _________ FAX: (______) _________ - _________ Application (optional): Would you like a reply? Device: PIC16F684 Y N Literature Number: DS41202C Questions: 1. What are the best features of this document? 2. How does this document meet your hardware and software development needs? 3. Do you find the organization of this document easy to follow? If not, why? 4. What additions to the document do you think would enhance the structure and subject? 5. What deletions from the document could be made without affecting the overall usefulness? 6. Is there any incorrect or misleading information (what and where)? 7. How would you improve this document? DS41202C-page 160 Preliminary 2004 Microchip Technology Inc. PIC16F684 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. X PART NO. Device Temperature Range /XX XXX Package Pattern Examples: a) b) Device 16F: Standard VDD range 16FT: (Tape and Reel) Temperature Range I E Package P SL ST Pattern 3-Digit Pattern Code for QTP (blank otherwise) = = PIC16F684-E/P 301 = Extended Temp., PDIP package, 20 MHz, QTP pattern #301 PIC16F684-I/SO = Industrial Temp., SOIC package, 20 MHz -40°C to +85°C -40°C to +125°C = = = PDIP SOIC (Gull wing, 150 mil body) TSSOP(4.4 mm) * JW Devices are UV erasable and can be programmed to any device configuration. JW Devices meet the electrical requirement of each oscillator type. 2004 Microchip Technology Inc. Preliminary DS41202C-page 161 WORLDWIDE SALES AND SERVICE AMERICAS China - Beijing Korea Corporate Office Unit 706B Wan Tai Bei Hai Bldg. No. 6 Chaoyangmen Bei Str. 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