PIC16F636-I Datasheet, PDF (55/234 Pages) Microchip Technology – 8/14-Pin, Flash-Based 8-Bit CMOS Microcontrollers with nanoWatt Technology

PIC12F635/PIC16F636/639
4.2.4.2 RA1/C1IN-/VREF/ICSPCLK
Figure 4-2 shows the diagram for this pin. The RA1 pin
is configurable to function as one of the following:
• a general purpose I/O
• an analog input to the comparator
• In-Circuit Serial Programming™ clock
FIGURE 4-2:
Data Bus
DQ
WR
WPUDA
CK _Q
RD
WPUDA
WR
WDA
DQ
CK _Q
BLOCK DIAGRAM OF RA1
Analog
Input Mode⁽¹⁾
VDD
Weak
RAPU
Weak
VSS
RD
WDA
DQ
VDD
WR
PORTA
CK _Q
WR
TRISA
DQ
CK _Q
RD
TRISA
I/O pin
VSS
Analog
Input Mode⁽¹⁾
RD
PORTA
DQ
WR
IOCA
CK _Q
RD
IOCA
QD
EN
Q1
QD
EN
Interrupt-on-
change
RD PORTA
To Comparator
Note 1: Comparator mode determines Analog Input mode.
4.2.4.3 RA2/T0CKI/INT/C1OUT
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
• the clock input for Timer0
• an external edge-triggered interrupt
• a digital output from the comparator
FIGURE 4-3:
BLOCK DIAGRAM OF RA2
Data Bus
DQ
WR
WPUDA
CK _Q
RD
WPUDA
WR
WDA
DQ
CK _Q
RD
WDA
WR
PORTA
DQ
CK _Q
WR
TRISA
DQ
CK _Q
RAPU
C1OUT
Enable
C1OUT 1
0
VDD
Weak
Weak
VSS
VDD
I/O pin
VSS
RD
TRISA
RD
PORTA
DQ
WR
IOCA
CK _Q
RD
IOCA
Interrupt-on-
change
QD
EN
Q1
QD
EN
RD PORTA
To Timer0
To INT
© 2007 Microchip Technology Inc.
DS41232D-page 53