
2009 Microchip Technology Inc.
DS39887C-page 11
PIC18F2458/2553/4458/4553
TABLE 1-2:
PIC18F2458/2553 PINOUT I/O DESCRIPTIONS
Pin Name
Pin
Number Pin
Type
Buffer
Type
Description
SPDIP,
SOIC
MCLR/VPP/RE3
MCLR
VPP
RE3
1
I
P
I
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
9
I
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
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
Note 1:
Alternate assignment for CCP2 when CCP2MX Configuration bit is cleared.
2:
Default assignment for CCP2 when CCP2MX Configuration bit is set.