Datasheet

 2010 Microchip Technology Inc. DS39616D-page 19
PIC18F2331/2431/4331/4431
TABLE 1-3: PIC18F4331/4431 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type
Description
PDIP TQFP QFN
MCLR
/VPP/RE3
MCLR
VPP
RE3
11818
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. Available only when MCLR
is disabled.
OSC1/CLKI/RA7
OSC1
CLKI
RA7
13 30 32
I
I
I/O
ST
CMOS
TTL
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
14 31 33
O
O
I/O
—
—
TTL
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or resonator
in Crystal Oscillator mode.
In RC mode, OSC2 pin outputs CLKO, which has 1/4 the
frequency of OSC1 and denotes the instruction cycle rate.
General purpose I/O 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
Note 1: RC3 is the alternate pin for T0CKI/T5CKI; RC4 is the alternate pin for SDI/SDA; RC5 is the alternate pin
for SCK/SCL; RC7 is the alternate pin for SDO.
2: RD4 is the alternate pin for FLTA
.
3: RD5 is the alternate pin for PWM4.