PIC16F870/871
TABLE 1-1:
PIC16F870 PINOUT DESCRIPTION
DIP
Pin#
SOIC
Pin#
I/O/P
Type
Buffer
Type
Pin Name
Description
(3)
OSC1/CLKIN
9
9
I
Oscillator crystal input/external clock source input.
ST/CMOS
OSC2/CLKOUT
10
10
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 can also be analog input0
RA1 can also be analog input1
RA0/AN0
2
3
4
2
3
4
I/O
I/O
I/O
TTL
TTL
TTL
RA1/AN1
RA2/AN2/VREF-
RA2 can also be analog input2 or negative analog reference
voltage
RA3/AN3/VREF+
RA4/T0CKI
RA5/AN4
5
6
7
5
6
7
I/O
I/O
I/O
TTL
ST
RA3 can also be analog input3 or positive analog reference
voltage
RA4 can also be the clock input to the Timer0 module. Output
is open drain type.
TTL
RA5 can also be analog input4
PORTB is a bi-directional I/O port. PORTB can be software
programmed for internal weak pull-up on all inputs.
(1)
RB0/INT
21
21
I/O
RB0 can also be the external interrupt pin.
TTL/ST
TTL
RB1
22
23
24
22
23
24
I/O
I/O
I/O
RB2
TTL
(1)
RB3/PGM
RB3 can also be the low voltage programming input
TTL/ST
TTL
RB4
25
26
27
25
26
27
I/O
I/O
I/O
Interrupt on change pin.
Interrupt on change pin.
RB5
TTL
(2)
(2)
RB6/PGC
Interrupt on change pin or In-Circuit Debugger pin. Serial
programming clock.
TTL/ST
RB7/PGD
28
11
28
11
I/O
I/O
Interrupt on change pin or In-Circuit Debugger pin. Serial
programming data.
TTL/ST
PORTC is a bi-directional I/O port.
RC0/T1OSO/T1CKI
ST
RC0 can also be the Timer1 oscillator output or Timer1 clock
input.
RC1/T1OSI
RC2/CCP1
12
13
12
13
I/O
I/O
ST
ST
RC1 can also be the Timer1 oscillator input
RC2 can also be the Capture1 input/Compare1 output/PWM1
output.
RC3
14
15
16
17
14
15
16
17
I/O
I/O
I/O
I/O
ST
ST
ST
ST
RC4
RC5
RC6/TX/CK
RC6 can also be the USART Asynchronous Transmit or
Synchronous Clock.
RC7/RX/DT
18
18
I/O
ST
RC7 can also be the USART Asynchronous Receive or
Synchronous Data.
VSS
8, 19
20
8, 19
20
P
P
—
—
Ground reference for logic and I/O pins.
Positive supply for logic and I/O pins.
VDD
Legend: I = input
O = output
— = Not used
I/O = input/output
TTL = TTL input
P = power
ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as the 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 in RC oscillator mode and a CMOS input otherwise.
1999 Microchip Technology Inc.
Preliminary
DS30569A-page 7
MICROCHIP [ MICROCHIP ]
