PIC16F627A_05 Datasheet, PDF (41/180 Pages) Microchip Technology – Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

PIC16F627A/628A/648A
FIGURE 5-12:
RBPU
BLOCK DIAGRAM OF RB4/PGM PIN
VDD
P _{weak pull-up}
Data Bus
WR PORTB
WR TRISB
RD TRISB
LVP (Configuration Bit)
RD PORTB
PGM input
D
Q
CK Q
Data Latch
D
Q
CK Q
TRIS Latch
Schmitt
Trigger
Set RBIF
From other
RB<7:4> pins
VDD
RB4/PGM
VSS
TTL
input
buffer
Q
D
EN
Q1
Q
D
Q3
EN
Note: The low-voltage programming disables the interrupt-on-change and the weak pull-ups on RB4.
© 2005 Microchip Technology Inc.
DS40044D-page 39