PIC16F818/819
FIGURE 5-15:
BLOCK DIAGRAM OF RB7 PIN
Port/Program Mode/ICD
PGD
1
0
VDD
(2)
RBPU
Weak
Pull-up
P
Data Latch
Data Bus
D
Q
WR
PORTB
(1)
I/O pin
CK
TRIS Latch
D
Q
0
1
WR
TRISB
CK
RD TRISB
T1OSCEN
T1OSCEN
Analog
Input Mode
PGD DRVEN
TTL
Input Buffer
Latch
Q
Q
D
EN
Q1
RD PORTB
Set RBIF
D
From other
RB7:RB4 pins
RD PORTB
Q3
EN
PGD
To T1OSI Input
Note 1: I/O pins have diode protection to VDD and VSS.
2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.
DS39598E-page 52
2004 Microchip Technology Inc.