PIC16F818/819
TABLE 1-2:
Pin Name
PIC16F818/819 PINOUT DESCRIPTIONS
PDIP/
SSOP QFN
SOIC
Pin# Pin#
Pin#
I/O/P
Type
Buffer
Type
Description
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
RA1/AN1
RA1
AN1
RA2/AN2/V
REF
-
RA2
AN2
V
REF
-
RA3/AN3/V
REF
+
RA3
AN3
V
REF
+
RA4/AN4/T0CKI
RA4
AN4
T0CKI
RA5/MCLR/V
PP
RA5
MCLR
17
19
23
I/O
I
TTL
Analog
TTL
Analog
TTL
Analog
Analog
TTL
Analog
Analog
ST
Analog
ST
ST
ST
Bidirectional I/O pin.
Analog input channel 0.
Bidirectional I/O pin.
Analog input channel 1.
Bidirectional I/O pin.
Analog input channel 2.
A/D reference voltage (low) input.
Bidirectional I/O pin.
Analog input channel 3.
A/D reference voltage (high) input.
Bidirectional I/O pin.
Analog input channel 4.
Clock input to the TMR0 timer/counter.
Input pin.
Master Clear (Reset). Input/programming
voltage input. This pin is an active-low Reset
to the device.
Programming threshold voltage.
Bidirectional I/O pin.
Oscillator crystal output. Connects to crystal or
resonator in Crystal Oscillator mode.
In RC mode, this pin outputs CLKO signal
which has 1/4 the frequency of OSC1 and
denotes the instruction cycle rate.
Bidirectional I/O pin.
Oscillator crystal input.
External clock source input.
18
20
24
I/O
I
1
1
26
I/O
I
I
2
2
27
I/O
I
I
3
3
28
I/O
I
I
4
4
1
I
I
V
PP
RA6/OSC2/CLKO
RA6
OSC2
CLKO
15
17
20
P
I/O
O
O
–
ST
–
–
RA7/OSC1/CLKI
RA7
OSC1
CLKI
16
18
21
I/O
I
I
ST
ST/CMOS
(3)
–
Legend:
I = Input
O = Output
I/O = Input/Output
P = Power
– = Not used
TTL = TTL Input
ST = Schmitt Trigger Input
Note 1:
This buffer is a Schmitt Trigger input when configured as the external interrupt.
2:
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
3:
This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
2004 Microchip Technology Inc.
DS39598E-page 7
MICROCHIP [ MICROCHIP TECHNOLOGY ]
