
PIC18CXX8
DS30475A-page 12
Advanced Information
2000 Microchip Technology Inc.
TABLE 1-2:
PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
Pin
Type
Buffer
Type
PIC18C658
PIC18C858
TQFP
PLCC
TQFP
PLCC
Description
MCLR/VPP
MCLR
VPP
7
16920
I
P
ST
Master clear (RESET) input. This pin is
an active low RESET to the device.
Programming voltage input
NC
—
1, 18,
35, 52
—
1, 22,
43, 64
——
These pins should be left
unconnected
OSC1/CLKI
OSC1
CLKI
39
50
49
62
I
CMOS/ST
CMOS
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
40
51
50
63
O
I/O
—
TTL
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 VDD)