PIC16C72 Series
TABLE 1-1
Pin Name
OSC1/CLKIN
OSC2/CLKOUT
PIC16C72/CR72 PINOUT DESCRIPTION
Pin#
9
10
I/O/P
Type
I
O
Buffer
Type
Description
ST/CMOS
(3)
Oscillator crystal input/external clock source input.
—
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.
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.
RA3 can also be analog input3 or analog reference voltage
RA4 can also be the clock input to the Timer0 module. 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.
RB0 can also be the external interrupt pin.
MCLR/V
PP
1
I/P
ST
RA0/AN0
RA1/AN1
RA2/AN2
RA3/AN3/V
REF
RA4/T0CKI
RA5/SS/AN4
2
3
4
5
6
7
I/O
I/O
I/O
I/O
I/O
I/O
TTL
TTL
TTL
TTL
ST
TTL
RB0/INT
RB1
RB2
RB3
RB4
RB5
RB6
RB7
RC0/T1OSO/T1CKI
RC1/T1OSI
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6
RC7
V
SS
V
DD
Legend: I = input
21
22
23
24
25
26
27
28
11
12
13
14
15
16
17
18
8, 19
20
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
P
P
TTL/ST
(1)
TTL
TTL
TTL
TTL
TTL
TTL/ST
(2)
TTL/ST
(2)
ST
ST
ST
ST
ST
ST
ST
ST
—
—
Interrupt on change pin.
Interrupt on change pin.
Interrupt on change pin. Serial programming clock.
Interrupt on change pin. Serial programming data.
PORTC is a bi-directional I/O port.
RC0 can also be the Timer1 oscillator output or Timer1 clock
input.
RC1 can also be the Timer1 oscillator input.
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).
Ground reference for logic and I/O pins.
Positive supply for logic and I/O pins.
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 the 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 in RC oscillator mode and a CMOS input otherwise
.
DS39016A-page 4
Preliminary
©
1998 Microchip Technology Inc.
MICROCHIP [ MICROCHIP TECHNOLOGY ]
