
PIC16F688
DS41203E-page 6
2009 Microchip Technology Inc.
TABLE 1-1:
PIC16F688 PINOUT DESCRIPTION
Name
Function
Input
Type
Output
Type
Description
RA0/AN0/C1IN+/ICSPDAT/ULPWU
RA0
TTL
CMOS
PORTA I/O w/prog pull-up and interrupt-on-change
AN0
AN
—
A/D Channel 0 input
C1IN+
AN
—
Comparator 1 input
ICSPDAT
TTL
CMOS
Serial Programming Data I/O
ULPWU
AN
—
Ultra Low-Power Wake-up input
RA1/AN1/C1IN-/VREF/ICSPCLK
RA1
TTL
CMOS
PORTA I/O w/prog pull-up and interrupt-on-change
AN1
AN
—
A/D Channel 1 input
C1IN-
AN
—
Comparator 1 input
VREF
AN
—
External Voltage Reference for A/D
ICSPCLK
ST
—
Serial Programming Clock
RA2/AN2/T0CKI/INT/C1OUT
RA2
ST
CMOS
PORTA I/O w/prog pull-up and interrupt-on-change
AN2
AN
—
A/D Channel 2 input
T0CKI
ST
—
Timer0 clock input
INT
ST
—
External Interrupt
C1OUT
—
CMOS
Comparator 1 output
RA3/MCLR/VPP
RA3
TTL
—
PORTA input with interrupt-on-change
MCLR
ST
—
Master Clear w/internal pull-up
VPP
HV
—
Programming voltage
RA4/AN3/T1G/OSC2/CLKOUT
RA4
TTL
CMOS
PORTA I/O w/prog pull-up and interrupt-on-change
AN3
AN
—
A/D Channel 3 input
T1G
ST
—
Timer1 gate
OSC2
—
XTAL
Crystal/Resonator
CLKOUT
—
CMOS
FOSC/4 output
RA5/T1CKI/OSC1/CLKIN
RA5
TTL
CMOS
PORTA I/O w/prog pull-up and interrupt-on-change
T1CKI
ST
—
Timer1 clock
OSC1
XTAL
—
Crystal/Resonator
CLKIN
ST
—
External clock input/RC oscillator connection
RC0/AN4/C2IN+
RC0
TTL
CMOS
PORTC I/O
AN4
AN
—
A/D Channel 4 input
C2IN+
AN
Comparator 2 input
RC1/AN5/C2IN-
RC1
TTL
CMOS
PORTC I/O
AN5
AN
—
A/D Channel 5 input
C2IN-
AN
Comparator 2 input
RC2/AN6
RC2
TTL
CMOS
PORTC I/O
AN6
AN
—
A/D Channel 6 input
RC3/AN7
RC3
TTL
CMOS
PORTC I/O
AN7
AN
—
A/D Channel 7 input
RC4/C2OUT/TX/CK
RC4
TTL
CMOS
PORTC I/O
C2OUT
—
CMOS
Comparator 2 output
TX
—
CMOS
USART asynchronous output
CK
ST
CMOS
USART asynchronous clock
RC5/RX/DT
RC5
TTL
CMOS
Port C I/O
RX
ST
CMOS
USART asynchronous input
DT
ST
CMOS
USART asynchronous data
VSS
Power
—
Ground reference
VDD
Power
—
Positive supply
Legend:
AN
= Analog input or output
CMOS = CMOS compatible input or output
OC = Open collector output
TTL
= TTL compatible input
ST
= Schmitt Trigger input with CMOS levels
HV
= High Voltage
XTAL
= Crystal