Datasheet

PIC12F635/PIC16F636/639

4.2.4 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 individual functions,

such as the comparator, refer to the appropriate section

in this data sheet.

4.2.4.1 RA0/C1IN+/ICSPDAT/ULPWU

Figure 4-2 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 to the comparator

• In-Circuit Serial Programming™ data

• an analog input for the Ultra Low-Power Wake-up

FIGURE 4-1: BLOCK DIAGRAM OF RA0

I/O pin

VDD

VSS

VDD

Weak

RD PORTA

IOCA

Interrupt-on-

Analog

Input Mode

(1)

Change

IULP

WPUDA

Data Bus

WPUDA

PORTA

TRISA

PORTA

Note 1: Comparator mode determines Analog Input mode.

ULPWUE

–

WDA

Analog

Input Mode

(1)

RAPU

Weak