PIC16F87XA Datasheet, PDF (12/234 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers

PIC16F87XA
TABLE 1-3: PIC16F874A/877A PINOUT DESCRIPTION
Pin Name
PDIP PLCC TQFP QFN I/O/P
Pin# Pin# Pin# Pin# Type
Buffer
Type
Description
OSC1/CLKI
OSC1
CLKI
13
14 30
32
ST/CMOS^{(4) Oscillator crystal or external clock input.}
I
Oscillator crystal input or external clock source
input. ST buffer when configured in RC mode;
otherwise CMOS.
I
External clock source input. Always associated
with pin function OSC1 (see OSC1/CLKI,
OSC2/CLKO pins).
OSC2/CLKO
OSC2
CLKO
14
15 31
33
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
1
2
18
18
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
2
3
19
19
TTL
I/O
I
Digital I/O.
Analog input 0.
RA1/AN1
RA1
AN1
3
4
20
20
TTL
I/O
I
Digital I/O.
Analog input 1.
RA2/AN2/VREF-/CVREF 4
5
21
21
TTL
RA2
I/O
AN2
I
VREF-
I
CVREF
O
Digital I/O.
Analog input 2.
A/D reference voltage (Low) input.
Comparator VREF output.
RA3/AN3/VREF+
RA3
AN3
VREF+
5
6
22
22
TTL
I/O
I
I
Digital I/O.
Analog input 3.
A/D reference voltage (High) input.
RA4/T0CKI/C1OUT
6
7
23
23
ST
RA4
I/O
T0CKI
I
C1OUT
O
Digital I/O – Open-drain when configured as
output.
Timer0 external clock input.
Comparator 1 output.
RA5/AN4/SS/C2OUT
7
8
24
24
TTL
RA5
I/O
AN4
I
SS
I
C2OUT
O
Digital I/O.
Analog input 4.
SPI slave select input.
Comparator 2 output.
Legend:
Note 1:
2:
3:
I = input
O = output
I/O = input/output
P = power
— = Not used TTL = TTL input ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as the external interrupt.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
DS39582B-page 10
 2003 Microchip Technology Inc.