
PIC18FXX39
DS30485A-page 14
Preliminary
2002 Microchip Technology Inc.
TABLE 1-3:
PIC18F4X39 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type
Description
DIP
QFN TQFP
MCLR/VPP
MCLR
VPP
118
18
I
ST
Master Clear (input) or high voltage ICSP
programming enable pin.
Master Clear (Reset) input. This pin is an active
low RESET to the device.
High voltage ICSP programming enable pin.
OSC1/CLKI
OSC1
CLKI
13
32
30
I
CMOS
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source
input.
External clock source input. Always associated
with pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
OSC2/CLKO/RA6
OSC2
CLKO
RA6
14
33
31
O
I/O
—
TTL
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal
or resonator in Crystal Oscillator mode.
In EC mode, OSC2 pin outputs CLKO,
which has 1/4 the frequency of OSC1 and
denotes the instruction cycle rate.
General purpose I/O pin.
PORTA is a bi-directional 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-
RA2
AN2
VREF-
421
21
I/O
I
TTL
Analog
Digital I/O.
Analog input 2.
A/D Reference Voltage (Low) input.
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
RA4
T0CKI
623
23
I/O
I
ST/OD
ST
Digital I/O. Open drain when configured as output.
Timer0 external clock input.
RA5/AN4/SS/LVDIN
RA5
AN4
SS
LVDIN
724
24
I/O
I
TTL
Analog
ST
Analog
Digital I/O.
Analog input 4.
SPI Slave Select input.
Low Voltage Detect input.
RA6
(See the OSC2/CLKO/RA6 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 VDD)