PIC16F688 Datasheet, PDF (39/174 Pages) Microchip Technology – 14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

4.2.4.3 RA2/AN2/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
• an analog input for the A/D
• the clock input for TMR0
• an external edge triggered interrupt
• a digital output from the comparator
FIGURE 4-3:
Data Bus
DQ
WR
WPUA
CK _Q
RD
WPUA
DQ
WR
PORTA
CK _Q
WR
TRISA
DQ
CK _Q
RD
TRISA
BLOCK DIAGRAM OF RA2
Analog⁽¹⁾
Input Mode
VDD
Weak
RAPU
C1OUT
Enable
VDD
C1OUT 1
0
I/O pin
VSS
Analog⁽¹⁾
Input Mode
RD
PORTA
DQ
WR
IOCA
CK _Q
RD
IOCA
Interrupt-on-
change
QD
EN
Q3
QD
EN
RD PORTA
To TMR0
To INT
To A/D Converter
Note 1: Analog Input mode is based upon ANSEL.
PIC16F688
4.2.4.4 RA3/MCLR/VPP
Figure 4-4 shows the diagram for this pin. The RA3 pin
is configurable to function as one of the following:
• a general purpose input
• as Master Clear Reset with weak pull-up
FIGURE 4-4:
BLOCK DIAGRAM OF RA3
MCLRE
VDD
Weak
Data Bus
Reset
RD
VSS
TRISA
RD
PORTA
DQ
WR
IOCA
CK _Q
RD
IOCA
Interrupt-on-
change
MCLRE
MCLRE
QD
EN
QD
EN
RD PORTA
Input
pin
VSS
Q3
 2004 Microchip Technology Inc.
Preliminary
DS41203B-page 37