Datasheet

PIC18F2450/4450
DS39760D-page 12 © 2008 Microchip Technology Inc.
TABLE 1-2: PIC18F2450 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type
Description
SPDIP,
SOIC
QFN
MCLR
/VPP/RE3
MCLR
VPP
RE3
126
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
OSC1
CLKI
96
I
I
Analog
Analog
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 OSC2/CLKO pin.)
OSC2/CLKO/RA6
OSC2
CLKO
RA6
10 7
O
O
I/O
—
—
TTL
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or resonator
in Crystal Oscillator mode.
In select modes, 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