PIC16F87X
TABLE 1-2:
Pin Name
OSC1/CLKIN
OSC2/CLKOUT
PIC16F874 AND PIC16F877 PINOUT DESCRIPTION
DIP
Pin#
13
14
PLCC
Pin#
14
15
QFP
Pin#
30
31
I/O/P
Type
I
O
Buffer
Type
ST/CMOS
(4)
—
Description
Oscillator crystal input/external clock source input.
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.
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
RA2 can also be analog input2 or negative analog
reference voltage
RA3 can also be analog input3 or positive analog
reference voltage
RA4 can also be the clock input to the Timer0 timer/
counter. Output is open drain type.
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.
MCLR/V
PP
/THV
1
2
18
I/P
ST
RA0/AN0
RA1/AN1
RA2/AN2/V
REF
-
RA3/AN3/V
REF
+
RA4/T0CKI
RA5/SS/AN4
2
3
4
5
6
7
3
4
5
6
7
8
19
20
21
22
23
24
I/O
I/O
I/O
I/O
I/O
I/O
TTL
TTL
TTL
TTL
ST
TTL
RB0/INT
RB1
RB2
RB3/PGM
RB4
RB5
RB6/PGC
RB7/PGD
33
34
35
36
37
38
39
40
36
37
38
39
41
42
43
44
8
9
10
11
14
15
16
17
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
TTL/ST
(1)
TTL
TTL
TTL
TTL
TTL
TTL/ST
(2)
TTL/ST
(2)
RB0 can also be the external interrupt pin.
RB3 can also be the low voltage programming input
Interrupt on change pin.
Interrupt on change pin.
Interrupt on change pin or In-Circuit Debugger pin. Serial
programming clock.
Interrupt on change pin or In-Circuit Debugger pin. Serial
programming data.
PORTC is a bi-directional I/O port.
RC0 can also be the Timer1 oscillator output or a Timer1
clock input.
RC1 can also be the Timer1 oscillator input or Capture2
input/Compare2 output/PWM2 output.
RC2 can also be the Capture1 input/Compare1 output/
PWM1 output.
RC3 can also be the synchronous serial clock input/output
for both SPI and I
2
C modes.
RC4 can also be the SPI Data In (SPI mode) or
data I/O (I
2
C mode).
RC5 can also be the SPI Data Out
(SPI mode).
RC6 can also be the USART Asynchronous Transmit or
Synchronous Clock.
RC7 can also be the USART Asynchronous Receive or
Synchronous Data.
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
Legend:
Note 1:
2:
3:
4:
I = input
15
16
17
18
23
24
25
26
16
18
19
20
25
26
27
29
32
35
36
37
42
43
44
1
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
ST
ST
ST
ST
ST
ST
ST
ST
O = output
I/O = input/output
P = power
— = Not used
TTL = TTL input
ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as an external interrupt.
This buffer is a Schmitt Trigger input when used in serial programming mode.
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).
This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise.
DS30292B-page 8
©
1999 Microchip Technology Inc.
ETC [ ETC ]
