PIC16F872
TABLE 3-3:
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
bit2
bit3
TTL
TTL
TTL/ST(1)
Input/output pin. Internal software programmable weak pull-up.
Input/output pin. Internal software programmable weak pull-up.
RB2
RB3/PGM
Input/output pin or programming pin in LVP mode. Internal software
programmable weak pull-up.
RB4
bit4
bit5
bit6
bit7
TTL
Input/output pin (with interrupt on change). Internal software programmable
weak pull-up.
RB5
TTL
Input/output pin (with interrupt on change). Internal software programmable
weak pull-up.
RB6/PGC
RB7/PGD
TTL/ST(2)
TTL/ST(2)
Input/output pin (with interrupt on change) or In-Circuit Debugger pin.
Internal software programmable weak pull-up. Serial programming clock.
Input/output pin (with interrupt on change) or In-Circuit Debugger pin.
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 configured as the external interrupt or LVP mode.
2: This buffer is a Schmitt Trigger input when used in serial programming mode.
TABLE 3-4:
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Value on: Value on all
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3 Bit 2 Bit 1 Bit 0
POR,
BOR
other
resets
06h, 106h
86h, 186h
PORTB
RB7
RB6
RB5
RB4
RB3
RB2
PS2
RB1
PS1
RB0 xxxx xxxx uuuu uuuu
TRISB
PORTB Data Direction Register
RBPU INTEDG T0CS T0SE PSA
1111 1111 1111 1111
81h, 181h
OPTION_REG
PS0 1111 1111 1111 1111
Legend: x= unknown, u= unchanged. Shaded cells are not used by PORTB.
DS30221A-page 26
Preliminary
1999 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
