PIC16C55X(A)
TABLE 3-1:
Name
PIC16C55X(A) PINOUT DESCRIPTION
DIP
SSOP
Pin #
I/O/P
Type
Buffer
Type
SOIC
Pin #
Description
OSC1/CLKIN
16
15
18
17
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.
4
4
I/P
ST
Master clear (reset) input/programming voltage input.
This pin is an active low reset to the device.
MCLR/VPP
PORTA is a bi-directional I/O port.
RA0
17
18
1
19
20
1
I/O
I/O
I/O
I/O
I/O
ST
ST
ST
ST
ST
RA1
RA2
RA3
2
2
RA4/T0CKI
3
3
Can be selected to be the clock input to the Timer0
timer/counter. Output is open drain type.
PORTB is a bi-directional I/O port. PORTB can be
software programmed for internal weak pull-up on all
inputs.
(1)
RB0/INT
6
7
I/O
RB0/INT can also be selected as an external
interrupt pin.
TTL/ST
RB1
RB2
RB3
RB4
RB5
RB6
RB7
VSS
7
8
8
9
I/O
I/O
I/O
I/O
I/O
I/O
I/O
P
TTL
TTL
9
10
TTL
10
11
12
13
5
11
TTL
Interrupt on change pin.
12
TTL
Interrupt on change pin.
(2)
(2)
13
TTL/ST
TTL/ST
—
Interrupt on change pin. Serial programming clock.
Interrupt on change pin. Serial programming data.
Ground reference for logic and I/O pins.
Positive supply for logic and I/O pins.
14
5,6
15,16
VDD
14
P
—
Legend:
O = output
— = Not used
TTL = TTL input
I/O = input/output
I = Input
P = power
ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
Note 2: This buffer is a Schmitt Trigger input when used in serial programming mode.
1997 Microchip Technology Inc.
Preliminary
DS40143B-page 11