
PIC16C71X
DS30272A-page 28
1997 Microchip Technology Inc.
FIGURE 5-4:
BLOCK DIAGRAM OF
RB7:RB4 PINS
(PIC16C71)
Data Latch
From other
RBPU(2)
P
VDD
I/O
Q
D
CK
Q
D
CK
Q
D
EN
Q
D
EN
Data bus
WR Port
WR TRIS
Set RBIF
TRIS Latch
RD TRIS
RD Port
RB7:RB4 pins
weak
pull-up
RD Port
Latch
TTL
Input
Buffer
pin(1)
ST
Buffer
RB7:RB6 in serial programming mode
Note 1: I/O pins have diode protection to VDD and VSS.
2: TRISB = ’1’ enables weak pull-up if
RBPU = ’0’ (OPTION<7>).
FIGURE 5-5:
BLOCK DIAGRAM OF
RB7:RB4 PINS
(PIC16C710/711/715)
Data Latch
From other
RBPU(2)
P
VDD
I/O
Q
D
CK
Q
D
CK
Q
D
EN
Q
D
EN
Data bus
WR Port
WR TRIS
Set RBIF
TRIS Latch
RD TRIS
RD Port
RB7:RB4 pins
weak
pull-up
RD Port
Latch
TTL
Input
Buffer
pin(1)
ST
Buffer
RB7:RB6 in serial programming mode
Q3
Q1
Note 1: I/O pins have diode protection to VDD and VSS.
2: TRISB = ’1’ enables weak pull-up if
RBPU = ’0’ (OPTION<7>).
TABLE 5-3:
PORTB FUNCTIONS
Name
Bit#
Buffer
Function
RB0/INT
bit0
TTL/ST(1)
Input/output pin or external interrupt input. Internal software
programmable weak pull-up.
RB1
bit1
TTL
Input/output pin. Internal software programmable weak pull-up.
RB2
bit2
TTL
Input/output pin. Internal software programmable weak pull-up.
RB3
bit3
TTL
Input/output pin. Internal software programmable weak pull-up.
RB4
bit4
TTL
Input/output pin (with interrupt on change). Internal software programmable
weak pull-up.
RB5
bit5
TTL
Input/output pin (with interrupt on change). Internal software programmable
weak pull-up.
RB6
bit6
TTL/ST(2)
Input/output pin (with interrupt on change). Internal software programmable
weak pull-up. Serial programming clock.
RB7
bit7
TTL/ST(2)
Input/output pin (with interrupt on change). Internal software programmable
weak pull-up. Serial programming data.
Legend: TTL = TTL input, ST = Schmitt Trigger input
Note 1: This buffer is a Schmitt Trigger input when congured as the external interrupt.
2: This buffer is a Schmitt Trigger input when used in serial programming mode.