Datasheet

© 2009 Microchip Technology Inc. DS41203E-page 37
PIC16F688
4.2.5 PIN DESCRIPTIONS AND
DIAGRAMS
Each PORTA pin is multiplexed with other functions.
The pins and their combined functions are briefly
described here. For specific information about individ-
ual functions such as the comparator or the A/D, refer
to the appropriate section in this data sheet.
4.2.5.1 RA0/AN0/C1IN+/ICSPDAT/ULPWU
Figure 4-1 shows the diagram for this pin. The RA0 pin
is configurable to function as one of the following:
• a general purpose I/O
• an analog input for the A/D
• an analog input to the comparator
• an analog input to the Ultra Low-Power Wake-up
• In-Circuit Serial Programming™ data
FIGURE 4-1: BLOCK DIAGRAM OF RA0
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
RD PORTA
RD
WR
WR
RD
WR
IOCA
RD
IOCA
Interrupt-on-
To Comparator
Analog
(1)
Input Mode
RAPU
Analog
(1)
Input Mode
Change
Q3
WR
RD
01
IULP
WPUDA
Data Bus
WPUDA
PORTA
TRISA
TRISA
PORTA
Note 1: Comparator mode and ANSEL determines analog Input mode.
-
+V
T
ULPWUE
To A/D Converter
Vss