Datasheet

PIC16F87XA
DS39582C-page 8  2001-2013 Microchip Technology Inc.
TABLE 1-2: PIC16F873A/876A PINOUT DESCRIPTION
Pin Name
PDIP, SOIC,
SSOP Pin#
QFN
Pin#
I/O/P
Type
Buffer
Type
Description
OSC1/CLKI
OSC1
CLKI
9
6
I
I
ST/CMOS
(3)
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
10 7
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
126
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 bidirectional I/O port.
RA0/AN0
RA0
AN0
227
I/O
I
TTL
Digital I/O.
Analog input 0.
RA1/AN1
RA1
AN1
328
I/O
I
TTL
Digital I/O.
Analog input 1.
RA2/AN2/V
REF-/
CV
REF
RA2
AN2
V
REF-
CV
REF
41
I/O
I
I
O
TTL
Digital I/O.
Analog input 2.
A/D reference voltage (Low) input.
Comparator V
REF output.
RA3/AN3/V
REF+
RA3
AN3
V
REF+
52
I/O
I
I
TTL
Digital I/O.
Analog input 3.
A/D reference voltage (High) input.
RA4/T0CKI/C1OUT
RA4
T0CKI
C1OUT
63
I/O
I
O
ST
Digital I/O – Open-drain when configured as output.
Timer0 external clock input.
Comparator 1 output.
RA5/AN4/SS
/C2OUT
RA5
AN4
SS
C2OUT
74
I/O
I
I
O
TTL
Digital I/O.
Analog input 4.
SPI slave select input.
Comparator 2 output.
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 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.