Datasheet

PIC18F2331/2431/4331/4431
DS39616D-page 16  2010 Microchip Technology Inc.
TABLE 1-2: PIC18F2331/2431 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type
Description
SPDIP,
SOIC
QFN
MCLR
/VPP
MCLR
VPP
126
I
P
ST
Master Clear (input) or programming voltage (input).
Master Clear (Reset) input. This pin is an active-low
Reset to the device.
High-voltage ICSP™ programming enable pin.
OSC1/CLKI/RA7
OSC1
CLKI
RA7
96
I
I
I/O
ST
CMOS
TTL
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode; CMOS otherwise.
External clock source input. Always associated with pin
function OSC1. (See related OSC1/CLKI, OSC2/CLKO
pins.)
General purpose I/O pin.
OSC2/CLKO/RA6
OSC2
CLKO
RA6
10 7
O
O
I/O
—
—
TTL
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.
General purpose I/O pin.
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
227
I/O
I
TTL
Analog
Digital I/O.
Analog Input 0.
RA1/AN1
RA1
AN1
328
I/O
I
TTL
Analog
Digital I/O.
Analog Input 1.
RA2/AN2/V
REF-/CAP1/INDX
RA2
AN2
V
REF-
CAP1
INDX
41
I/O
I
I
I
I
TTL
Analog
Analog
ST
ST
Digital I/O.
Analog Input 2.
A/D reference voltage (low) input.
Input Capture Pin 1.
Quadrature Encoder Interface index input pin.
RA3/AN3/V
REF+/CAP2/QEA
RA3
AN3
V
REF+
CAP2
QEA
52
I/O
I
I
I
I
TTL
Analog
Analog
ST
ST
Digital I/O.
Analog Input 3.
A/D reference voltage (high) input.
Input Capture Pin 2.
Quadrature Encoder Interface Channel A input pin.
RA4/AN4/CAP3/QEB
RA4
AN4
CAP3
QEB
63
I/O
I
I
I
TTL
Analog
ST
ST
Digital I/O.
Analog Input 4.
Input Capture Pin 3.
Quadrature Encoder Interface Channel B input pin.
Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power