Datasheet

© 2009 Microchip Technology Inc. DS39632E-page 17
PIC18F2455/2550/4455/4550
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
21919
I/O
I
TTL
Analog
Digital I/O.
Analog input 0.
RA1/AN1
RA1
AN1
32020
I/O
I
TTL
Analog
Digital I/O.
Analog input 1.
RA2/AN2/V
REF-/
CV
REF
RA2
AN2
V
REF-
CV
REF
42121
I/O
I
I
O
TTL
Analog
Analog
Analog
Digital I/O.
Analog input 2.
A/D reference voltage (low) input.
Analog comparator reference output.
RA3/AN3/V
REF+
RA3
AN3
V
REF+
52222
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog input 3.
A/D reference voltage (high) input.
RA4/T0CKI/C1OUT/
RCV
RA4
T0CKI
C1OUT
RCV
62323
I/O
I
O
I
ST
ST
—
TTL
Digital I/O.
Timer0 external clock input.
Comparator 1 output.
External USB transceiver RCV input.
RA5/AN4/SS
/
HLVDIN/C2OUT
RA5
AN4
SS
HLVDIN
C2OUT
72424
I/O
I
I
I
O
TTL
Analog
TTL
Analog
—
Digital I/O.
Analog input 4.
SPI slave select input.
High/Low-Voltage Detect input.
Comparator 2 output.
RA6 — — — — — See the OSC2/CLKO/RA6 pin.
TABLE 1-3: PIC18F4455/4550 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number
Pin
Type
Buffer
Type
Description
PDIP QFN TQFP
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: Alternate assignment for CCP2 when CCP2MX Configuration bit is cleared.
2: Default assignment for CCP2 when CCP2MX Configuration bit is set.
3: These pins are No Connect unless the ICPRT Configuration bit is set. For NC/ICPORTS, the pin is No
Connect unless ICPRT is set and the DEBUG
Configuration bit is cleared.