
PIC18F2331/2431/4331/4431
DS39616D-page 20
2010 Microchip Technology Inc.
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
219
19
I/O
I
TTL
Analog
Digital I/O.
Analog Input 0.
RA1/AN1
RA1
AN1
320
20
I/O
I
TTL
Analog
Digital I/O.
Analog Input 1.
RA2/AN2/VREF-/CAP1/
INDX
RA2
AN2
VREF-
CAP1
INDX
421
21
I/O
I
TTL
Analog
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/VREF+/
CAP2/QEA
RA3
AN3
VREF+
CAP2
QEA
522
22
I/O
I
TTL
Analog
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
623
23
I/O
I
TTL
Analog
ST
Digital I/O.
Analog Input 4.
Input Capture Pin 3.
Quadrature Encoder Interface Channel B input pin.
RA5/AN5/LVDIN
RA5
AN5
LVDIN
724
24
I/O
I
TTL
Analog
Digital I/O.
Analog Input 5.
Low-Voltage Detect input.
TABLE 1-3:
PIC18F4331/4431 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number
Pin
Type
Buffer
Type
Description
PDIP TQFP QFN
Legend:
TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
O
= Output
P
= Power
Note 1:
RC3 is the alternate pin for T0CKI/T5CKI; RC4 is the alternate pin for SDI/SDA; RC5 is the alternate pin
for SCK/SCL; RC7 is the alternate pin for SDO.
2:
RD4 is the alternate pin for FLTA.
3:
RD5 is the alternate pin for PWM4.