PIC16F688
4.2.5.2
RA1/AN1/C1IN-/VREF/ICSPCLK
4.2.5.3
RA2/AN2/T0CKI/INT/C1OUT
Figure 4-2 shows the diagram for this pin. The RA1 pin
is configurable to function as one of the following:
Figure 4-3 shows the diagram for this pin. The RA2 pin
is configurable to function as one of the following:
• a general purpose I/O
• a general purpose I/O
• an analog input for the A/D
• an analog input for the A/D
• the clock input for Timer0
• an analog input to the comparator
• a voltage reference input for the A/D
• In-Circuit Serial Programming™ clock
• an external edge triggered interrupt
• a digital output from the comparator
FIGURE 4-2:
BLOCK DIAGRAM OF RA1
FIGURE 4-3:
BLOCK DIAGRAM OF RA2
Analog(1)
Input Mode
Analog(1)
Input Mode
Data Bus
D
Data Bus
D
Q
Q
VDD
Q
Q
VDD
WR
CK
WR
CK
Weak
Weak
WPUA
WPUA
RAPU
RD
WPUA
RAPU
RD
WPUA
C1OUT
Enable
VDD
VDD
D
Q
Q
D
Q
Q
WR
PORTA
WR
PORTA
CK
CK
C1OUT
1
0
I/O pin
I/O pin
D
Q
Q
D
Q
Q
WR
TRISA
WR
TRISA
CK
CK
VSS
VSS
Analog(1)
Analog(1)
Input Mode
Input Mode
RD
TRISA
RD
TRISA
RD
PORTA
RD
PORTA
D
Q
Q
D
Q
Q
Q
Q
D
Q
Q
D
CK
WR
IOCA
CK
WR
IOCA
Q3
EN
Q3
EN
RD
IOCA
RD
IOCA
D
D
EN
EN
Interrupt-on-
change
Interrupt-on-
change
RD PORTA
RD PORTA
To Comparator
To A/D Converter
To Timer0
To INT
To A/D Converter
Note 1: Comparator mode and ANSEL determines analog
Input mode.
Note 1: Analog Input mode is based upon ANSEL.
DS41203C-page 38
© 2007 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
