Datasheet

PIC18FXX8
DS41159E-page 10 © 2006 Microchip Technology Inc.
TABLE 1-2: PIC18FXX8 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type
DescriptionPIC18F248/258 PIC18F448/458
SPDIP, SOIC PDIP TQFP PLCC
MCLR/VPP
MCLR
VPP
11182
I
P
ST
—
Master Clear (input) or
programming voltage (output).
Master Clear (Reset) input.
This pin is an active low Reset
to the device.
Programming voltage input.
NC — — 12, 13,
33, 34
1, 17,
28, 40
— — These pins should be left
unconnected.
OSC1/CLKI
OSC1
CLKI
9 133014
I
I
CMOS/ST
CMOS
Oscillator crystal or external clock
input.
Oscillator crystal input or
external clock source input. ST
buffer when configured in RC
mode; otherwise, CMOS.
External clock source input.
Always associated with pin
function OSC1 (see OSC1/
CLKI, OSC2/CLKO pins).
OSC2/CLKO/RA6
OSC2
CLKO
RA6
10 14 31 15
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 Analog = Analog input
I = Input O = Output
P = Power OD = Open-Drain (no P diode to V
DD)