Target Board PIC877-TB - Reference Manual

Transcription

1 Target Board PIC877-TB - Reference Manual

2 Target Board PIC877-TB Reference Manual Feedback Feedback Instruments Ltd, Park Road, Crowborough, E. Sussex, TN6 2QR, UK. Telephone: +44 (0) , Fax: +44 (0) website: Manual: Ed Printed in England by Fl Ltd, Crowborough Feedback Part No

3 Notes

4 Preface THE HEALTH AND SAFETY AT WORK ACT 1974 We are required under the Health and Safety at Work Act 1974, to make available to users of this equipment certain information regarding its safe use. The equipment, when used in normal or prescribed applications within the parameters set for its mechanical and electrical performance, should not cause any danger or hazard to health or safety if normal engineering practices are observed and they are used in accordance with the instructions supplied. If, in specific cases, circumstances exist in which a potential hazard may be brought about by careless or improper use, these will be pointed out and the necessary precautions emphasised. While we provide the fullest possible user information relating to the proper use of this equipment, if there is any doubt whatsoever about any aspect, the user should contact the Product Safety Officer at Feedback Instruments Limited, Crowborough. This equipment should not be used by inexperienced users unless they are under supervision. We are required by European Directives to indicate on our equipment panels certain areas and warnings that require attention by the user. These have been indicated in the specified way by yellow labels with black printing, the meaning of any labels that may be fixed to the instrument are shown below: CAUTION - RISK OF DANGER Refer to accompanying documents CAUTION - RISK OF ELECTRIC SHOCK CAUTION - ELECTROSTATIC SENSITIVE DEVICE PRODUCT IMPROVEMENTS We maintain a policy of continuous product improvement by incorporating the latest developments and components into our equipment, even up to the time of dispatch. All major changes are incorporated into up-dated editions of our manuals and this manual was believed to be correct at the time of printing. However, some product changes which do not affect the instructional capability of the equipment, may not be included until it is necessary to incorporate other significant changes. COMPONENT REPLACEMENT Where components are of a Safety Critical nature, i.e. all components involved with the supply or carrying of voltages at supply potential or higher, these must be replaced with components of equal international safety approval in order to maintain full equipment safety. In order to maintain compliance with international directives, all replacement components should be identical to those originally supplied. Any component may be ordered direct from Feedback or its agents by quoting the following information: 1. Equipment type 2. Component value 3. Component reference 4. Equipment serial number Components can often be replaced by alternatives available locally, however we cannot therefore guarantee continued performance either to published specification or compliance with international standards i

5 Preface DECLARATION CONCERNING ELECTROMAGNETIC COMPATIBILITY Should this equipment be used outside the classroom, laboratory study area or similar such place for which it is designed and sold then Feedback Instruments Ltd hereby states that conformity with the protection requirements of the European Community Electromagnetic Compatibility Directive (89/336/EEC) may be invalidated and could lead to prosecution. This equipment, when operated in accordance with the supplied documentation, does not cause electromagnetic disturbance outside its immediate electromagnetic environment. COPYRIGHT NOTICE Feedback Instruments Limited All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of Feedback Instruments Limited. ACKNOWLEDGEMENTS Feedback Instruments Ltd acknowledge all trademarks. IBM, IBM - PC are registered trademarks of International Business Machines. MICROSOFT, WINDOWS 98, WINDOWS 95, WINDOWS 3.1 are registered trademarks of Microsoft Corporation. MPLAB and PIC are registered trademarks of Microchip Technology Inc ii

6 Preface COPYRIGHT NOTICE GnB 1995, All Rights Reserved Copyright of the PIC 877 Target Board (PIC 877-TB), its associated software and documentation belongs to GnB and may not be used, sold, licensed, transferred, copied or reproduced in any manner or form other than with written permission of GnB. Purchase of this product entitles the purchaser to use the software on a single machine but does not constitute ownership of the software. Unauthorised copying, lending, or redistribution of the software or documentation in any manner constitutes breach of copyright. Software piracy is theft. DISCLAIMER No warranties of any kind are made with respect to the contents of this software package, nor its fitness for any particular purpose. Neither GnB or any associates or subcontractors shall be liable for errors in the software or documentation, or for any direct, indirect or consequential damages or financial losses arising from the use of the package. TRADEMARKS PIC is a registered trademark of the Microchip Technology Inc. USA iii

7 Preface Notes iv

8 Contents TABLE OF CONTENTS 1 Introduction Getting Started Installing Software Connecting the System Starting the System The Screen Explained Read Details Read Options Read Range Configuration Programming Details The Menus File Menu Load Exit Program Menu Program Program Data Config Erase Program Erase Data Erase All Read Menu Comms TOC-1

9 Contents 2.10 Control Switches Tutorial I/O Connectors Way Connector P Way Connector P Serial I/O Pinout Way Connector P Connector P Board Layout Circuit Diagrams 6-1 Appendix A Data Sheet A-1 TOC

10 Chapter 1 Introduction 1 Introduction The 877-TB (target board) enables the user to program the PIC16F877 microcontroller via a serial port on a PC and then run the program at the flick of a switch without the need to remove the device. The 877-TB is constructed on a high quality double-sided through plated printed circuit board and is powered from a single rail power supply. The board holds all circuitry necessary to program and run programs developed of the PIC16F877 microcontroller. Onboard LED s indicate the current operation (Running a program, Loading a program or Idle) that is controlled using two switches: A pushbutton to start and stop programs (reset or not reset). A slide-switch to switch between programming and operation mode. The 877-TB has a variety of connectors fitted that allow the user to connect their own applications. All available I/O lines are assessable via screw terminals located around the perimeter of the PCB. Each terminal is identified on the PCB and is designated with its respective pin on the PIC16F877. Three IDC connectors are also provided and allow the unit to be connected to a number of application boards. Four switches are also fitted on the board that allow logic 0 and 1 to be set to inputs RC0, RE0, RE1 and RE2 on the 16F877. The power supply requirement is + 6V to +15V unregulated dc at 1A maximum. When purchased as a Microcontroller trainer a suitable PSU is included in the package. Microchips website provides a vast amount of information on the 16F877 microcontroller, including manuals, application notes and data sheets. The crossassembler and MPLAB (an integrated development system for the full range of microcontrollers) can be freely downloaded

11 Chapter 1 Introduction 1.1 Getting Started You should have the following: 877-TB unit. PSU (included in Micro trainer package only). Serial Lead. Disk with communication software. Manual. 1.2 Installing Software The communications software consists of a single executable file. Programs are developed using Microchips assembler and are loaded to the 877-TB using the communications software via the serial link (com1 to com4). Place the distribution disk supplied into drive A, start windows explorer and select the drive you wish the copy the communications software to (usually Drive C). Then create a new folder by selecting File New Folder: Figure 1-1 A new folder will appear in the explorer window: Figure 1-2 Right-click the folder and select Rename from the menu. Enter the name you wish to give the folder (877TB)

12 Chapter 1 Introduction Now select drive A and click the 877TB executable file, select copy from the edit menu then enter the new folder (877TB) by double clicking it. Finally select past from the edit menu. The programming software will then be copied from the distribution disk. In order to place a shortcut on the desktop right-click the application file and select Create Shortcut form the menu. A shortcut will appear in the same folder, select it and drag it to the desktop. 1.3 Connecting the System The unit can be connected to serial ports 1 to 4 on any IBM compatible PC running Microsoft Windows 95 or above or Windows NT 4.0 or above. Connect the unit to the serial port, make sure the PRG/RUN switch id in the PRG position, THEN apply the power (the PWR LED will light). PS U 877TB Figure Starting the System The system can now be started from the desktop by double clicking the shortcut on the

13 Chapter 1 Introduction desktop. The application will look on each available serial port and try to detect the unit see Figure 1-4. Figure 1-4 Once the target board has been detected, the onboard 877TB can be programmed, erased and reprogrammed. The Status Bar at the bottom of the window indicates which serial port is being used if the board was detected. If the board could not be detected a Device NOT Found message is indicated on the Status Bar and a number of the menu items (such as program etc) will not be available

14 Chapter 2 The Screen Explained 2 The Screen Explained The screen shown in Figure 1-4 is to some extent self-explanatory. The window is divided into three sections and a pull-down menu: Read Details. Configuration. Programming Details 2.1 Read Details Figure Read Options These radio buttons select which areas of the 877TB will be read into the PC memory. Prog. Memory Prog. and Configuration Prog. Memory + Data All Reads program memory only. Reads program memory and the device configuration. Reads program memory and data memory. Reads program memory, data memory and device configuration

15 Chapter 2 The Screen Explained 2.2 Read Range All operations on the 877TB are performed serially onboard. This is a relatively slow process. Sometimes only a small section of the memory is of interest. In order to cut down the read times the user can choose to read a selected range of program memory. This is achieved using the Read Range sections. Full Range Selected Range Reads all program memory range from 0000 to 1FFFh. Read the program memory range specified in the Read Range section. 2.3 Configuration Figure 2-2 The 877TB has a number of configuration options. Some options cannot be changed here because the device is attached to the PCB and therefore parameters such as oscillator frequency are not selectable. Those parameters that can be selected by the user are done so within the configuration section. WRT CPD Code Protect WDTE This enables/disables flash program memory writes. Switches data EE memory code protection on or off. Selects the level of code protection. Enables/disables the watch dog timer

16 Chapter 2 The Screen Explained 2.4 Programming Details This is very similar to the Read Details section. The difference is that the device is programmed instead of being read. Figure The Menus All operations on the system are performed using pull down menus. There are four main menus: File Program Read Comms Figure File Menu The pull down file menu has only two items: Load Exit

17 Chapter 2 The Screen Explained Load Use load to load a binary program into the computer prior to programming. When load is selected the user is presented with a load dialogue screen, for example: Figure 2-5 The default file extension is HEX as produced by Microchips cross-assembler. When a file is loaded the program range is from the lowest address loaded to the highest address loaded. Of course this can be set by the user simply by clicking into the From and To boxes in the Programming Range box and entering a new value (in hex) Exit Selecting Exit closes the program

18 Chapter 2 The Screen Explained 2.7 Program Menu This menu header has six items: Figure Program This programs the device according to the selections in the Programming Options box. Either program memory only, program and configuration memory, program and data memory or all. A progress bar indicates programming progress Program Data This programs the 64 bytes of data memory in the 16F Config This programs the configuration word into the device as indicated in the Configuration section. (Note that some configuration options cannot be set by the user since the device is fixed onto the board and its circuitry)

19 Chapter 2 The Screen Explained Erase Program Selecting this causes the program memory only within the device to be erased Erase Data Selecting this option causes the data memory within the device to be erased Erase All This erases the whole device including the configuration, even if the protect bits are set to protect all. It is recommended that this operation is performed prior to programming the device. 2.8 Read Menu The Read menu contains five items: Figure Read Prog. This reads the program memory selected by the From and To values in the Read Details section. The Read Selected Range is set by default and the range can be set by clicking into the From and To boxes and entering the required values. Figure

20 Chapter 2 The Screen Explained The Read Options box controls which memory is read. Only the program memory is read if the Prog. Memory radio button is selected, the program memory and configuration is read if the Prog. and Configuration is selected, the program and data memory is read if the Prog. Memory + Data radio button is selected and program, data and configuration is read if the All radio button is selected Read Data This reads the 64 bytes of data memory only Read Config. This reads the current configuration of the device. The configuration section is set according to the configuration read and the configuration value (in hex) is displayed in the status bar Blank Check This checks that the program memory is blank. This operation can take some time since data must be read serially. The result is shown in the status bar Verify Verify reads the program memory and compares it to the data held in the PC (which will be data read from file or the device using the Read Prog. option), the result is shown in the status bar. 2.9 Comms There is only one item in the comms menu, which is Detect. Figure 2-9 This looks for the 877TB board on all available serial ports, if the system is found the com port used is displayed on the status bar otherwise a device not found message is displayed

21 Chapter 2 The Screen Explained 2.10 Control Switches The operation of the unit is controlled by two switches, slide switch S1 (PRG/RUN) and pushbutton S2 (START/STOP). To program the 16F877 via the software the PRG/RUN switch should be in the PRG position. To run the program, slide the PRG/RUN switch to the RUN position, now pressing the START/STOP switch toggles the reset line to the 16F877. The current state is indicated by the RUN (green) LED

22 Chapter 3 Tutorial 3 Tutorial This section is intended as a practical introduction to developing programs for the PICF877 microcontroller using the 877-TB development system. The program will simply toggle all the bits on port D on and off: Enter the following program using a text editor such and Microsoft Notepad or Edit (do not use a word processor) or use the program ex1.asm on the distribution disk. list p = 16f877 include <p16f877.inc> delay_vhi equ H'20' delay_hi equ H'21' delay_lo equ H'22' ORG goto ORG H'00' start H'10' ;initialise port to safe conditions start BCF STATUS, RP0 ; bank 0 CLRF PORTD ; Initialize PORTD by clearing output latches BSF STATUS, RP0 ; select bank1 movlw 0x00 ; w reg =00 movwf TRISD ; Set RB as outputs movlw 0xFF ; W reg = FF hex BCF STATUS, RP0 ; bank 0 ;************************** main movlw 0xFF ; bit pattern FF movwf PORTD ; output w reg to portb call delay clrf PORTD ; clear portb call delay goto main ;************************************ ;subroutines ;************************************ delay movlw 0x01 movwf delay_lo movlw 0xA1 movwf delay_hi movlw 0xF4 movwf delay_vhi outer mid inner incfsz delay_lo,1 goto inner incfsz goto mid delay_hi,

23 Chapter 3 Tutorial incfsz goto outer return END delay_vhi,1 Cross assemble the program to produce a HEX file using Microchips MPASM for widows which is included on the disk supplied (or other suitable cross assembler). On starting MPASM for windows the following screen will be displayed: Figure

24 Chapter 3 Tutorial Select the 16F877 processor and the file ex1.asm, then click the Assemble button. If all is well, the following screen will be displayed: Figure 3-2 Click the OK button and the window will close. Assuming that the system is connected and the PRG/RUN switch set to the PRG (program) position, start the 877-TB software by double clicking the icon on the desktop (the one that was created previously in the section on installing software). If all is well the software will detect the system and display the connected to port message in the status bar

25 Chapter 3 Tutorial Figure 3-3 Now select Load from the File menu and select the ex1.hex file just created. The program will be loaded into the PC ready for downloading. The Programming Range will be set to the appropriate values (the highest & lowest addresses used) and then select the Prog. and Configure radio button. Figure

26 Chapter 3 Tutorial In order to make sure the PIC16F877 is blank erase the device by selecting Erase All option from the Program menu, then select the Program option to program the device. The progress bar will be displayed indicating programming status and the PRG and RUN (red and green respectively) will light. When programming is complete the LED s will switch off and the screen should look as follows: Figure 3-5 Once programmed successfully, the system can be switched to the run mode by switching the PRG/RUN switch to the RUN position. Initially the PIC16F877 is in the reset condition (reset pin low). Pressing the START/STOP push button toggles the reset line, when the reset is inactive (program running) the RUN LED (green) lights. Use a suitable device (Logic Probe or oscilloscope) to monitor PORT D outputs or connect a suitable circuit, such as an array of LED s (with suitable current limiting resistors)

27 Chapter 3 Tutorial Notes

28 Chapter 3 I/O Connectors 4 I/O Connectors Way Connector P Function PIN No Function PIN No N/C 1 N/C 2 N/C 3 N/C 4 N/C 5 N/C 6 N/C 7 N/C 8 N/C 9 N/C 10 N/C 11 N/C Volts Volts 14 RA0 15 RE1 16 RA1 17 RE0 18 RA2 19 RA5 20 RA3 21 RA4 22 RD0 23 RD7 24 RD1 25 RD6 26 RD2 27 RD5 28 RD3 29 RD4 30 RB0 31 RB7 32 RB1 33 RB6 34 RB2 35 RB5 36 RB3 37 RB Volts 39 0 Volts

29 Chapter 3 I/O Connectors Way Connector P Function PIN No Function PIN No RA0 1 RA1 2 RA2 3 RA3 4 RA4 5 RA5 6 RE0 7 RE1 8 0 Volts 9 RD0 10 RD1 11 RD2 12 RD3 13 RD4 14 RD5 15 RD6 16 RD Volts 18 RB0 19 RB1 20 RB2 21 RB3 22 RB4 23 RB5 24 RB6 25 RB

30 Chapter 3 I/O Connectors 4.3 Serial I/O Pinout P2 D Type Socket Pin Function 1 N/C 2 RxD 3 TxD 4 DTR 5 GND 6 DSR 7 RTS 8 CTS 9 N/C

31 Chapter 3 I/O Connectors Way Connector P Function PIN No Function PIN No RA0 1 RA1 2 RA2 3 RA3 4 RA4 5 RA5 6 RE0 7 RE1 8 RE2 9 RC0 10 RC1 11 RC2 12 RC3 13 RC4 14 RC5 15 RB Volts 17 RB1 18 RB2 19 RB

32 Chapter 3 I/O Connectors 4.5 Connector P4 Pin 1 +5V Function 2 Ground 3 Ground 4 RC4/SDA 5 RC5/SAO

33 Chapter 3 I/O Connectors Notes

34 Chapter 4 Board Layout 5 Board Layout All available I/O lines are also connected to the screw terminal connectors TB1 to TB4 on the top and bottom edges of the PCB. Figure

35 Chapter 4 Board Layout Notes

36 Chapter 5 Circuit Diagrams 6 Circuit Diagrams The circuit diagrams are shown on the following two pages:

37 Chapter 5 Circuit Diagrams VCC P SERIAL PORT + C3 + C5 U1 4.7uF 4.7uF + C4 4.7uF V -10V T1out T2out R1in R2in Gnd +C 1 +10V -C 1 +C 2 -C 2 T1in T2in R1out R2out C6 4.7uF R14 1K U3 8 V+ 5 4 REF SHDN 7 LX MAX761 3 FB LBO 1 2 LBI 6 GND C10 0.1uF 10K R7 R8 10K + L1 44uH C12 44uF VCC + C11 44uF 12V D4 1N5817 Max232 R6 1K Q1 BC109 Q2 BC212L IC4 MCLR VCC + VCC R2 10K C7 10uF R3 10K R R U2 RA2 RA1 RA3 RA0 RA4 MCLR Vss RB0 RB1 RB2 OSC1 OSC2 Vdd RB7 RB6 RB5 RB3 RB4 PIC16F Y1 4MHz C8 33pF C9 33pF IC4 RB7 (PGD) IC4 RB6 (PGC) IC4 RC6 (TX) R5 330 D2 PROG R R11 10K Q3 BC109 R9 10K VCC R D3 RUN S1 IC4 RC7 (RX) S2 RUN RUN/PROG Figure 6-1 Circuit Diagram 1 of

38 1 TARGET BOARD PIC877-TB Chapter 5 Circuit Diagrams 9V 1 2 P1 + C1 100uF 3 REG1 LM317 VIN ADJ VOUT 2 + C2 100uF C13 0.1uF C14 0.1uF Vcc C15 0.1uF R1 330 D1 POWER IC4 16F C16 33pF XT2 CRYSTAL RE0 R15 10K S4 SW SPDT VCC 15 C17 RE2 R16 S6 33pF 10K SW SPDT V RE1 RC0 R17 10K R18 S5 SW SPDT S3 RC4/SDA RC5/SDO P PIN D IN 34 10K SW SPDT Figure 6-2: Circuit Diagram 2 of

39 Chapter 5 Circuit Diagrams Notes

40 Appendix A Data Sheet Data Sheet Pages 5 to 9 of PIC16F87X Data Sheet are provided in Appendix A. Note: The Microchip Technology website provides development tools relevant to the Target Board at: A-1

41 Appendix A Data Sheet Notes A

42 PIC16F87X 1.0 DEVICE OVERVIEW This document contains device-specific information. Additional information may be found in the PICmicro Mid-Range Reference Manual, (DS33023), which may be obtained from your local Microchip Sales Representative or downloaded from the Microchip website. 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. There are four devices (PIC16F873, PIC16F874, PIC16F876 and PIC16F877) covered by this data sheet. The PIC16F876/873 devices come in 28-pin packages and the PIC16F877/874 devices come in 40- pin packages. The 28-pin devices do not have a Parallel Slave Port implemented. The following two figures are device block diagrams sorted by pin number; 28-pin for Figure 1-1 and 40-pin for Figure 1-2. The 28-pin and 40-pin pinouts are listed in Table 1-1 and Table 1-2, respectively. FIGURE 1-1: PIC16F873 AND PIC16F876 BLOCK DIAGRAM Device Program Bus OSC1/CLKIN OSC2/CLKOUT Program FLASH FLASH Program Memory 14 Instruction reg Instruction Decode & Control Timing Generation Data Memory 8 13 Program Counter 8 Level Stack (13-bit) Direct Addr 7 Power-up Timer Oscillator Start-up Timer Power-on Reset Watchdog Timer Brown-out Reset In-Circuit Debugger Low-Voltage Programming Data EEPROM PIC16F873 4K 192 Bytes 128 Bytes PIC16F876 8K 368 Bytes 256 Bytes Data Bus RAM File Registers RAM Addr (1) Addr MUX ALU W reg 8 FSR reg 8 Indirect Addr STATUS reg MUX PORTA PORTB PORTC RA0/AN0 RA1/AN1 RA2/AN2/VREF- RA3/AN3/VREF+ RA4/T0CKI RA5/AN4/SS RB0/INT RB1 RB2 RB3/PGM RB4 RB5 RB6/PGC RB7/PGD RC0/T1OSO/T1CKI RC1/T1OSI/CCP2 RC2/CCP1 RC3/SCK/SCL RC4/SDI/SDA RC5/SDO RC6/TX/CK RC7/RX/DT MCLR VDD, VSS Timer0 Timer1 Timer2 10-bit A/D Data EEPROM CCP1,2 Synchronous Serial Port USART Note 1: Higher order bits are from the STATUS register Microchip Technology Inc. DS30292B-page 5

43 PIC16F87X FIGURE 1-2: PIC16F874 AND PIC16F877 BLOCK DIAGRAM Device Program FLASH Data Memory Data EEPROM PIC16F874 4K 192 Bytes 128 Bytes PIC16F877 8K 368 Bytes 256 Bytes Program Bus OSC1/CLKIN OSC2/CLKOUT FLASH Program Memory 14 Instruction reg Instruction Decode & Control Timing Generation 8 13 Program Counter 8 Level Stack (13-bit) Direct Addr 7 Power-up Timer Oscillator Start-up Timer Power-on Reset Watchdog Timer Brown-out Reset Data Bus RAM File Registers RAM Addr (1) Addr MUX ALU W reg 8 FSR reg 8 Indirect Addr STATUS reg MUX PORTA PORTB PORTC PORTD RA0/AN0 RA1/AN1 RA2/AN2/VREF- RA3/AN3/VREF+ RA4/T0CKI RA5/AN4/SS RB0/INT RB1 RB2 RB3/PGM RB4 RB5 RB6/PGC RB7/PGD RC0/T1OSO/T1CKI RC1/T1OSI/CCP2 RC2/CCP1 RC3/SCK/SCL RC4/SDI/SDA RC5/SDO RC6/TX/CK RC7/RX/DT RD7/PSP7:RD0/PSP0 In-Circuit Debugger Low-Voltage Programming Parallel Slave Port PORTE RE0/AN5/RD MCLR VDD, VSS RE1/AN6/WR RE2/AN7/CS Timer0 Timer1 Timer2 10-bit A/D Data EEPROM CCP1,2 Synchronous Serial Port USART Note 1: Higher order bits are from the STATUS register. DS30292B-page Microchip Technology Inc.

44 PIC16F87X TABLE 1-1: PIC16F873 AND PIC16F876 PINOUT DESCRIPTION Pin Name DIP Pin# SOIC Pin# I/O/P Type Buffer Type Description OSC1/CLKIN 9 9 I ST/CMOS (3) Oscillator crystal input/external clock source input. OSC2/CLKOUT O Oscillator crystal output. Connects to crystal or resonator in crystal oscillator mode. In RC mode, the OSC2 pin outputs CLKOUT which has 1/4 the frequency of OSC1, and denotes the instruction cycle rate. MCLR/VPP/THV 1 1 I/P ST Master clear (reset) input or programming voltage input or high voltage test mode control. This pin is an active low reset to the device. PORTA is a bi-directional I/O port. RA0/AN0 2 2 I/O TTL RA0 can also be analog input0 RA1/AN1 3 3 I/O TTL RA1 can also be analog input1 RA2/AN2/VREF- 4 4 I/O TTL RA2 can also be analog input2 or negative analog reference voltage RA3/AN3/VREF+ 5 5 I/O TTL RA3 can also be analog input3 or positive analog reference voltage RA4/T0CKI 6 6 I/O ST RA4 can also be the clock input to the Timer0 module. Output is open drain type. RA5/SS/AN4 7 7 I/O TTL RA5 can also be analog input4 or the slave select for the synchronous serial port. PORTB is a bi-directional I/O port. PORTB can be software programmed for internal weak pull-up on all inputs. RB0/INT I/O TTL/ST (1) RB0 can also be the external interrupt pin. RB I/O TTL RB I/O TTL RB3/PGM I/O TTL RB3 can also be the low voltage programming input RB I/O TTL Interrupt on change pin. RB I/O TTL Interrupt on change pin. RB6/PGC I/O TTL/ST (2) Interrupt on change pin or In-Circuit Debugger pin. Serial programming clock. RB7/PGD I/O (2) TTL/ST Interrupt on change pin or In-Circuit Debugger pin. Serial programming data. PORTC is a bi-directional I/O port. RC0/T1OSO/T1CKI I/O ST RC0 can also be the Timer1 oscillator output or Timer1 clock input. RC1/T1OSI/CCP I/O ST RC1 can also be the Timer1 oscillator input or Capture2 input/ Compare2 output/pwm2 output. RC2/CCP I/O ST RC2 can also be the Capture1 input/compare1 output/pwm1 output. RC3/SCK/SCL I/O ST RC3 can also be the synchronous serial clock input/output for both SPI and I 2 C modes. RC4/SDI/SDA I/O ST RC4 can also be the SPI Data In (SPI mode) or data I/O (I 2 C mode). RC5/SDO I/O ST RC5 can also be the SPI Data Out (SPI mode). RC6/TX/CK I/O ST RC6 can also be the USART Asynchronous Transmit or Synchronous Clock. RC7/RX/DT I/O ST RC7 can also be the USART Asynchronous Receive or Synchronous Data. VSS 8, 19 8, 19 P Ground reference for logic and I/O pins. VDD P Positive supply for logic and I/O pins. Legend: I = input O = output I/O = input/output P = power = Not used TTL = TTL input ST = Schmitt Trigger input Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt. 2: This buffer is a Schmitt Trigger input when used in serial programming mode. 3: This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise Microchip Technology Inc. DS30292B-page 7

45 PIC16F87X TABLE 1-2: PIC16F874 AND PIC16F877 PINOUT DESCRIPTION Pin Name DIP Pin# PLCC Pin# QFP Pin# I/O/P Type Buffer Type Description OSC1/CLKIN I ST/CMOS (4) Oscillator crystal input/external clock source input. OSC2/CLKOUT O Oscillator crystal output. Connects to crystal or resonator in crystal oscillator mode. In RC mode, OSC2 pin outputs CLK- OUT which has 1/4 the frequency of OSC1, and denotes the instruction cycle rate. MCLR/VPP/THV I/P ST Master clear (reset) input or programming voltage input or high voltage test mode control. This pin is an active low reset to the device. PORTA is a bi-directional I/O port. RA0/AN I/O TTL RA0 can also be analog input0 RA1/AN I/O TTL RA1 can also be analog input1 RA2/AN2/VREF I/O TTL RA2 can also be analog input2 or negative analog reference voltage RA3/AN3/VREF I/O TTL RA3 can also be analog input3 or positive analog reference voltage RA4/T0CKI I/O ST RA4 can also be the clock input to the Timer0 timer/ counter. Output is open drain type. RA5/SS/AN I/O TTL RA5 can also be analog input4 or the slave select for the synchronous serial port. PORTB is a bi-directional I/O port. PORTB can be software programmed for internal weak pull-up on all inputs. RB0/INT I/O TTL/ST (1) RB0 can also be the external interrupt pin. RB I/O TTL RB I/O TTL RB3/PGM I/O TTL RB3 can also be the low voltage programming input RB I/O TTL Interrupt on change pin. RB I/O TTL Interrupt on change pin. RB6/PGC I/O TTL/ST (2) Interrupt on change pin or In-Circuit Debugger pin. Serial programming clock. RB7/PGD I/O (2) TTL/ST Interrupt on change pin or In-Circuit Debugger pin. Serial programming data. PORTC is a bi-directional I/O port. RC0/T1OSO/T1CKI I/O ST RC0 can also be the Timer1 oscillator output or a Timer1 clock input. RC1/T1OSI/CCP I/O ST RC1 can also be the Timer1 oscillator input or Capture2 input/compare2 output/pwm2 output. RC2/CCP I/O ST RC2 can also be the Capture1 input/compare1 output/ PWM1 output. RC3/SCK/SCL I/O ST RC3 can also be the synchronous serial clock input/output for both SPI and I 2 C modes. RC4/SDI/SDA I/O ST RC4 can also be the SPI Data In (SPI mode) or data I/O (I 2 C mode). RC5/SDO I/O ST RC5 can also be the SPI Data Out (SPI mode). RC6/TX/CK I/O ST RC6 can also be the USART Asynchronous Transmit or Synchronous Clock. RC7/RX/DT I/O ST RC7 can also be the USART Asynchronous Receive or Synchronous Data. Legend: I = input O = output I/O = input/output P = power = Not used TTL = TTL input ST = Schmitt Trigger input Note 1: This buffer is a Schmitt Trigger input when configured as an external interrupt. 2: This buffer is a Schmitt Trigger input when used in serial programming mode. 3: This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel Slave Port mode (for interfacing to a microprocessor bus). 4: This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise. DS30292B-page Microchip Technology Inc.

46 PIC16F87X TABLE 1-2: PIC16F874 AND PIC16F877 PINOUT DESCRIPTION (CONTINUED) Pin Name DIP Pin# PLCC Pin# QFP Pin# I/O/P Type Buffer Type RD0/PSP I/O ST/TTL (3) Description PORTD is a bi-directional I/O port or parallel slave port when interfacing to a microprocessor bus. RD1/PSP I/O ST/TTL (3) RD2/PSP I/O ST/TTL (3) RD3/PSP I/O ST/TTL (3) RD4/PSP I/O ST/TTL (3) RD5/PSP I/O ST/TTL (3) RD6/PSP I/O ST/TTL (3) RD7/PSP I/O ST/TTL (3) PORTE is a bi-directional I/O port. RE0/RD/AN I/O ST/TTL (3) RE0 can also be read control for the parallel slave port, or analog input5. RE1/WR/AN I/O (3) ST/TTL RE1 can also be write control for the parallel slave port, or analog input6. RE2/CS/AN I/O (3) ST/TTL RE2 can also be select control for the parallel slave port, or analog input7. VSS 12,31 13,34 6,29 P Ground reference for logic and I/O pins. VDD 11,32 12,35 7,28 P Positive supply for logic and I/O pins. NC 1,17,28, 40 12,13, 33,34 These pins are not internally connected. These pins should be left unconnected. Legend: I = input O = output I/O = input/output P = power = Not used TTL = TTL input ST = Schmitt Trigger input Note 1: This buffer is a Schmitt Trigger input when configured as an external interrupt. 2: This buffer is a Schmitt Trigger input when used in serial programming mode. 3: This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel Slave Port mode (for interfacing to a microprocessor bus). 4: This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise Microchip Technology Inc. DS30292B-page 9