Microchip Technology DM164134 Data Sheet
PIC18FXX8
DS41159E-page 10
© 2006 Microchip Technology Inc.
TABLE 1-2:
PIC18FXX8 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type
Description
PIC18F248/258
PIC18F448/458
SPDIP, SOIC
PDIP
TQFP
PLCC
MCLR/V
PP
MCLR
V
PP
1
1
18
2
I
P
ST
—
Master Clear (input) or
programming voltage (output).
programming voltage (output).
Master Clear (Reset) input.
This pin is an active low Reset
to the device.
Programming voltage 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.
unconnected.
OSC1/CLKI
OSC1
CLKI
9
13
30
14
I
I
CMOS/ST
CMOS
Oscillator crystal or external clock
input.
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).
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.
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
)