PIC16F7X
TABLE 1-3:
PIC16F74 AND PIC16F77 PINOUT DESCRIPTION
DIP
Pin#
PLCC
Pin#
QFP
Pin#
I/O/P
Type
Buffer
Type
Pin Name
Description
(4)
OSC1/CLKI
OSC1
13
14
30
ST/CMOS
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode. Otherwise
CMOS.
I
I
CLKI
External clock source input. Always associated with pin
function OSC1 (see OSC1/CLKI, OSC2/CLKO pins).
OSC2/CLKO
OSC2
14
15
31
—
Oscillator crystal or clock output.
Oscillator crystal output.
O
O
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.
CLKO
MCLR/VPP
MCLR
1
2
18
ST
Master Clear (input) or programming voltage (output).
Master Clear (Reset) input. This pin is an active low
RESET to the device.
I
VPP
P
Programming voltage input.
PORTA is a bi-directional I/O port.
RA0/AN0
RA0
2
3
4
5
3
4
5
6
19
20
21
22
TTL
TTL
TTL
TTL
I/O
I
Digital I/O.
Analog input 0.
AN0
RA1/AN1
RA1
I/O
I
Digital I/O.
Analog input 1.
AN1
RA2/AN2
RA2
I/O
I
Digital I/O.
Analog input 2.
AN2
RA3/AN3/VREF
RA3
I/O
Digital I/O.
AN3
VREF
I
I
Analog input 3.
A/D reference voltage input.
RA4/T0CKI
RA4
6
7
7
8
23
24
ST
I/O
I
Digital I/O – Open drain when configured as output.
Timer0 external clock input.
T0CKI
RA5/SS/AN4
RA5
TTL
I/O
Digital I/O.
SS
AN4
I
I
SPI slave select input.
Analog input 4.
Legend:
I = input
— = Not used
O = output
TTL = TTL input
I/O = input/output
ST = Schmitt Trigger input
P = power
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.
DS30325B-page 10
2002 Microchip Technology Inc.