PIC16F87XA
TABLE 1-3:
Pin Name
OSC1/CLKI
OSC1
PIC16F874A/877A PINOUT DESCRIPTION
DIP
Pin#
13
PLCC
Pin#
14
QFP
Pin#
30
I/O/P
Type
I
Buffer
Type
ST/CMOS
(4)
Description
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).
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.
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 bi-directional I/O port.
CLKI
OSC2/CLKOUT
OSC2
14
15
31
O
—
CLKO
MCLR/V
PP
MCLR
V
PP
RA0/AN0
RA0
AN0
RA1/AN1
RA1
AN1
RA2/AN2/V
REF
-/CV
REF
RA2
AN2
V
REF
-
CV
REF
RA3/AN3/V
REF
+
RA3
AN3
V
REF
+
RA4/T0CKI/C1OUT
RA4
T0CKI
C1OUT
RA5/SS/AN4/C2OUT
RA5
SS
AN4
C2OUT
Legend: I = input
1
2
18
I/P
ST
2
3
19
I/O
I
TTL
Digital I/O.
Analog input 0.
TTL
I/O
I
Digital I/O.
Analog input 1.
TTL
I/O
I
I
O
Digital I/O.
Analog input 2.
A/D reference voltage (Low) input.
Comparator V
REF
output.
TTL
I/O
I
I
Digital I/O.
Analog input 3.
A/D reference voltage (High) input.
ST
I/O
I
O
Digital I/O – Open drain when configured as output.
Timer0 external clock input.
Comparator 1 output.
TTL
I/O
I
I
O
Digital I/O.
SPI slave select input.
Analog input 4.
Comparator 2 output.
P = power
ST = Schmitt Trigger input
3
4
20
4
5
21
5
6
22
6
7
23
7
8
24
O = output
— = Not used
I/O = input/output
TTL = TTL 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.
DS39582A-page 10
Advance Information
2001 Microchip Technology Inc.
MICROCHIP [ MICROCHIP TECHNOLOGY ]
