Datasheet

PIC16C9XX
DS30444E - page 36  1997 Microchip Technology Inc.
5.4 PORTD and TRISD Registers
PORTD is an 8-bit port with Schmitt Trigger input buff-
ers. The first five pins are configurable as general pur-
pose I/O pins or LCD segment drivers. Pins RD5, RD6
and RD7 can be digital inputs or LCD segment or com-
mon drivers.
TRISD controls the direction of pins RD0 through RD4
when PORTD is configured as a digital port.
EXAMPLE 5-4: INITIALIZING PORTD
BCF STATUS,RP0 ;Select Bank2
BSF STATUS,RP1 ;
BCF LCDSE,SE29 ;Make RD<7:5> digital
BCF LCDSE,SE0 ;Make RD<4:0> digital
BSF STATUS,RP0 ;Select Bank1
BCF STATUS,RP1 ;
MOVLW 0x07 ;Make RD<4:0> outputs
MOVWF TRISD ;Make RD<7:5> inputs
Note: On a Power-on Reset these pins are con-
figured as LCD segment drivers.
Note: To configure the pins as a digital port, the
corresponding bits in the LCDSE register
must be cleared. Any bit set in the LCDSE
register overrides any bit settings in the
corresponding TRIS register.
FIGURE 5-6: PORTD<4:0> BLOCK
DIAGRAM
Data Bus
WR
WR
RD
Data Latch
TRIS Latch
Schmitt
Trigger
input
buffer
Q
D
CK
Q
D
CK
EN
Q D
EN
I/O pin
RD TRIS
LCDSE<n>
LCD
LCD Segment
Segment Data
Output Enable
PORT
TRIS
PORT