Datasheet
PIC16F7X
DS30325B-page 10 2002 Microchip Technology Inc.
TABLE 1-3: PIC16F74 AND PIC16F77 PINOUT DESCRIPTION
Pin Name
DIP
Pin#
PLCC
Pin#
QFP
Pin#
I/O/P
Type
Buffer
Type
Description
OSC1/CLKI
OSC1
CLKI
13 14 30
I
I
ST/CMOS
(4)
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode. Otherwise
CMOS.
External clock source input. Always associated with pin
function OSC1 (see OSC1/CLKI, OSC2/CLKO pins).
OSC2/CLKO
OSC2
CLKO
14 15 31
O
O
— Oscillator crystal or clock output.
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
MCLR
VPP
1218
I
P
ST Master Clear (input) or programming voltage (output).
Master Clear (Reset) input. This pin is an active low
RESET to the device.
Programming voltage input.
PORTA is a bi-directional I/O port.
RA0/AN0
RA0
AN0
2319
I/O
I
TTL
Digital I/O.
Analog input 0.
RA1/AN1
RA1
AN1
3420
I/O
I
TTL
Digital I/O.
Analog input 1.
RA2/AN2
RA2
AN2
4521
I/O
I
TTL
Digital I/O.
Analog input 2.
RA3/AN3/V
REF
RA3
AN3
V
REF
5622
I/O
I
I
TTL
Digital I/O.
Analog input 3.
A/D reference voltage input.
RA4/T0CKI
RA4
T0CKI
6723
I/O
I
ST
Digital I/O – Open drain when configured as output.
Timer0 external clock input.
RA5/SS/
AN4
RA5
SS
AN4
7824
I/O
I
I
TTL
Digital I/O.
SPI slave select input.
Analog input 4.
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.