Datasheet

PIC16F870/871
DS30569C-page 8  2000-2013 Microchip Technology Inc.
TABLE 1-2: PIC16F871 PINOUT DESCRIPTION
Pin Name
DIP
Pin#
PLCC
Pin#
QFP
Pin#
I/O/P
Type
Buffer
Type
Description
OSC1/CLKI 13 14 30 I
ST/CMOS
(4)
Oscillator crystal input/external clock source input.
OSC2/CLKO 14 15 31 O — Oscillator crystal output. Connects to crystal or resonator in
Crystal Oscillator mode. In RC mode, OSC2 pin outputs CLKO,
which has 1/4 the frequency of OSC1, and denotes the
instruction cycle rate.
MCLR
/VPP/THV 1 2 18 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 2319I/OTTL RA0 can also be analog input 0.
RA1/AN1 3420I/OTTL RA1 can also be analog input 1.
RA2/AN2/V
REF- 4521I/OTTL RA2 can also be analog input 2 or negative analog
reference voltage.
RA3/AN3/V
REF+ 5622I/OTTL RA3 can also be analog input 3 or positive analog
reference voltage.
RA4/T0CKI 6723I/O ST RA4 can also be the clock input to the Timer0
timer/counter. Output is open drain type.
RA5/AN4 7824I/OTTL RA5 can also be analog input 4.
PORTB is a bi-directional I/O port. PORTB can be software
programmed for internal weak pull-up on all inputs.
RB0/INT 33 36 8 I/O
TTL/ST
(1)
RB0 can also be the external interrupt pin.
RB1 34 37 9 I/O TTL
RB2 35 38 10 I/O TTL
RB3/PGM 36 39 11 I/O
TTL/ST
(1)
RB3 can also be the low voltage programming input.
RB4 37 41 14 I/O TTL Interrupt-on-change pin.
RB5 38 42 15 I/O TTL Interrupt-on-change pin.
RB6/PGC 39 43 16 I/O
TTL/ST
(2)
Interrupt-on-change pin or In-Circuit Debugger pin.
Serial programming clock.
RB7/PGD 40 44 17 I/O
TTL/ST
(2)
Interrupt-on-change pin or In-Circuit Debugger pin.
Serial programming data.
PORTC is a bi-directional I/O port.
RC0/T1OSO/T1CKI 15 16 32 I/O ST RC0 can also be the Timer1 oscillator output or a Timer1
clock input.
RC1/T1OSI 16 18 35 I/O ST RC1 can also be the Timer1 oscillator input.
RC2/CCP1 17 19 36 I/O ST RC2 can also be the Capture1 input/Compare1 output/
PWM1 output.
RC3 18 20 37 I/O ST
RC4 23 25 42 I/O ST
RC5 24 26 43 I/O ST
RC6/TX/CK 25 27 44 I/O ST RC6 can also be the USART Asynchronous Transmit or
Synchronous Clock.
RC7/RX/DT 26 29 1 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 or LVP mode.
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.