Datasheet
PIC16C55X
DS40143E-page 26 Preliminary 1996-2013 Microchip Technology Inc.
FIGURE 5-4: BLOCK DIAGRAM OF RB3:RB0 PINS
TABLE 5-3: PORTB FUNCTIONS
TABLE 5-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB AND TRISB
Name Bit # Buffer Type Function
RB0/INT Bit 0 TTL/ST
(1)
Bi-directional I/O port. Internal software programmable weak pull-up.
RB1 Bit 1 TTL Bi-directional I/O port. Internal software programmable weak pull-up.
RB2 Bit 2 TTL Bi-directional I/O port. Internal software programmable weak pull-up.
RB3 Bit 3 TTL Bi-directional I/O port. Internal software programmable weak pull-up.
RB4 Bit 4 TTL Bi-directional I/O port (with interrupt-on-change). Internal software programmable
weak pull-up.
RB5 Bit 5 TTL Bi-directional I/O port (with interrupt-on-change). Internal software programmable
weak pull-up.
RB6 Bit 6 TTL/ST
(2)
Bi-directional I/O port (with interrupt-on-change). Internal software programmable
weak pull-up. Serial programming clock pin.
RB7 Bit 7 TTL/ST
(2)
Bi-directional I/O port (with interrupt-on-change). Internal software programmable
weak pull-up. Serial programming data pin.
Legend: ST = Schmitt Trigger, TTL = TTL input
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Value on
POR
Value on
All Other
RESETS
06h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx uuuu uuuu
86h TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 1111 1111 1111 1111
81h OPTION RBPU
INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111
0BH, 8BH INTCON GIE
Reserved T0IE INTE BRIE T0IF INTF RBIF 0000 000x 0000 000x
Legend: x = unknown, u = unchanged
Note 1: Shaded bits are not used by PORTB.
P
N
VSS
VDD
RBPU
(1)
P
V
DD
I/O
Data Bus
WR PORTB
WR TRISB
RD TRISB
RD PORTB
weak
pull-up
RD PORTB
Latch
TTL
Input
Buffer
pin
ST
Buffer
RB0/INT
VDD
VSS
ST
Buffer
EN
Q
D
Data Latch
TRIS Latch
QD
CK
QD
Q
CK
Note 1: TRISB = 1 enables weak pull-up if RBPU = ‘0’ (OPTION<7>).