
PIC18F2458/2553/4458/4553
DS39887C-page 16
2009 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-/
CVREF
RA2
AN2
VREF-
CVREF
421
21
I/O
I
O
TTL
Analog
Digital I/O.
Analog input 2.
A/D reference voltage (low) input.
Analog comparator reference output.
RA3/AN3/VREF+
RA3
AN3
VREF+
522
22
I/O
I
TTL
Analog
Digital I/O.
Analog input 3.
A/D reference voltage (high) input.
RA4/T0CKI/C1OUT/
RCV
RA4
T0CKI
C1OUT
RCV
623
23
I/O
I
O
I
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
724
24
I/O
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:
PIC18F4458/4553 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.