Datasheet

Table Of Contents
PIC18F1220/1320
DS39605F-page 8 © 2007 Microchip Technology Inc.
TABLE 1-2: PIC18F1220/1320 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type
Description
PDIP/
SOIC
SSOP QFN
MCLR
/VPP/RA5
MCLR
VPP
RA5
441
I
P
I
ST
ST
Master Clear (input) or programming voltage (input).
Master Clear (Reset) input. This pin is an active-low
Reset to the device.
Programming voltage input.
Digital input.
OSC1/CLKI/RA7
OSC1
CLKI
RA7
16 18 21
I
I
I/O
ST
CMOS
ST
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
15 17 20
O
O
I/O
ST
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or
resonator in Crystal Oscillator mode.
In RC, EC and INTRC modes, OSC2 pin outputs
CLKO, which has 1/4 the frequency of OSC1 and
denotes instruction cycle rate.
General purpose I/O pin.
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
1126
I/O
I
ST
Analog
Digital I/O.
Analog input 0.
RA1/AN1/LVDIN
RA1
AN1
LVDIN
2227
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 1.
Low-Voltage Detect input.
RA2/AN2/V
REF-
RA2
AN2
V
REF-
677
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 2.
A/D reference voltage (low) input.
RA3/AN3/VREF+
RA3
AN3
V
REF+
788
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 3.
A/D reference voltage (high) input.
RA4/T0CKI
RA4
T0CKI
3328
I/O
I
ST/OD
ST
Digital I/O. Open-drain when configured as output.
Timer0 external clock input.
RA5 See the MCLR
/VPP/RA5 pin.
RA6 See the OSC2/CLKO/RA6 pin.
RA7 See the OSC1/CLKI/RA7 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
OD = Open-drain (no P diode to V
DD)