Datasheet

Table Of Contents
© 2009 Microchip Technology Inc. DS39689F-page 19
PIC18F2221/2321/4221/4321 FAMILY
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-/CVREF
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.
Comparator reference voltage 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
RA4
T0CKI
C1OUT
62323
I/O
I
O
ST
ST
Digital I/O.
Timer0 external clock input.
Comparator 1 output.
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.
RA7 See the OSC1/CLKI/RA7 pin.
TABLE 1-3: PIC18F4221/4321 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 P = Power
I
2
C = ST with I
2
C™ or SMB levels O = Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.