Datasheet

Table Of Contents
© 2008 Microchip Technology Inc. DS41262E-page 65
PIC16F631/677/685/687/689/690
4.2.5.2 RA1/AN1/C12IN0-/VREF/ICSPCLK
Figure 4-2 shows the diagram for this pin. The
RA1/AN1/C12IN0-/V
REF/ICSPCLK pin is configurable to
function as one of the following:
a general purpose I/O
an analog input for the ADC (except PIC16F631)
an analog input to Comparator C1 or C2
a voltage reference input for the ADC
In-Circuit Serial Programming clock
FIGURE 4-2: BLOCK DIAGRAM OF RA1
4.2.5.3 RA2/AN2/T0CKI/INT/C1OUT
Figure 4-3 shows the diagram for this pin. The
RA2/AN2/T0CKI/INT/C1OUT pin is configurable to
function as one of the following:
a general purpose I/O
an analog input for the ADC (except PIC16F631)
the clock input for Timer0
an external edge triggered interrupt
a digital output from Comparator C1
FIGURE 4-3: BLOCK DIAGRAM OF RA2
I/O Pin
VDD
VSS
D
Q
CK
Q
D
Q
CK
Q
D
Q
CK
Q
D
Q
CK
Q
VDD
D
EN
Q
D
EN
Q
Weak
Data Bus
WR
WPUA
RD
WPUA
RD PORTA
RD
PORTA
WR
PORTA
WR
TRISA
RD
TRISA
WR
IOCA
RD
IOCA
Interrupt-on-
To Comparator
Analog
(1)
Input Mode
RABPU
Analog
(1)
Input Mode
Change
Q3
Note 1: ANSEL determines Analog Input mode.
2: Not implemented on PIC16F631.
To A/D Converter
(2)
I/O Pin
VDD
VSS
D
Q
CK
Q
D
Q
CK
Q
D
Q
CK
Q
D
Q
CK
Q
VDD
D
EN
Q
D
EN
Q
Weak
Analog
(1)
Input Mode
Data Bus
WR
WPUA
RD
WPUA
RD
PORTA
WR
PORTA
WR
TRISA
RD
TRISA
WR
IOCA
RD
IOCA
To A/D Converter
(2)
0
1
C1OUT
C1OUT
Enable
To INT
To Tim e r 0
Analog
(1)
Input Mode
RABPU
RD PORTA
Interrupt-on-
Change
Q3
Note 1: ANSEL determines Analog Input mode.
2: Not implemented on PIC16F631.