PIC16F636-I Datasheet, PDF (56/234 Pages) Microchip Technology – 8/14-Pin, Flash-Based 8-Bit CMOS Microcontrollers with nanoWatt Technology

PIC12F635/PIC16F636/639
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
• a high-voltage detect for Program mode entry
FIGURE 4-4:
BLOCK DIAGRAM OF RA3
VDD
Program
Mode
MCLRE
HV Detect
Weak
Data Bus
RD
TRISA
RD
PORTA
DQ
WR
IOCA
CK _Q
RD
IOCA
Reset
VSS
MCLRE
MCLRE
Input
pin
VSS
QD
EN
Q1
QD
EN
RD PORTA
Interrupt-on-
change
WURE
Sleep
DS41232D-page 54
© 2007 Microchip Technology Inc.