PIC16C7X
TABLE 3-3:
PIC16C74/74A/77 PINOUT DESCRIPTION
DIP
Pin#
PLCC
Pin#
QFP I/O/P
Pin# Type
Buffer
Type
Pin Name
Description
(4)
OSC1/CLKIN
13
14
14
15
30
31
I
ST/CMOS
—
Oscillator crystal input/external clock source input.
OSC2/CLKOUT
O
Oscillator crystal output. Connects to crystal or resonator in
crystal oscillator mode. In RC mode, OSC2 pin outputs
CLKOUT which has 1/4 the frequency of OSC1, and
denotes the instruction cycle rate.
MCLR/VPP
1
2
18
I/P
ST
Master clear (reset) input or programming voltage input.
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
RA0/AN0
2
3
4
5
3
4
5
6
19
20
21
22
I/O
I/O
I/O
I/O
TTL
TTL
TTL
TTL
RA1/AN1
RA2/AN2
RA3/AN3/VREF
RA3 can also be analog input3 or analog reference
voltage
RA4/T0CKI
6
7
7
8
23
24
I/O
I/O
ST
RA4 can also be the clock input to the Timer0 timer/
counter. Output is open drain type.
RA5/SS/AN4
TTL
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.
(1)
RB0/INT
RB1
33
34
35
36
37
38
39
40
36
37
38
39
41
42
43
44
8
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
TTL/ST
TTL
RB0 can also be the external interrupt pin.
9
RB2
10
11
14
15
16
17
TTL
RB3
TTL
RB4
TTL
Interrupt on change pin.
RB5
TTL
Interrupt on change pin.
(2)
RB6
TTL/ST
TTL/ST
Interrupt on change pin. Serial programming clock.
Interrupt on change pin. Serial programming data.
(2)
RB7
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 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.
1997 Microchip Technology Inc.
DS30390E-page 15
MICROCHIP [ MICROCHIP ]
