
PIC18F2450/4450
2006 Microchip Technology Inc.
Advance Information
DS39760A-page 107
9.4
PORTD, TRISD and LATD
Registers
PORTD is an 8-bit wide, bidirectional port. The
corresponding data direction register is TRISD. Setting
a TRISD bit (= 1) will make the corresponding PORTD
pin an input (i.e., put the corresponding output driver in
a high-impedance mode). Clearing a TRISD bit (= 0)
will make the corresponding PORTD pin an output (i.e.,
put the contents of the output latch on the selected pin).
The Data Latch register (LATD) is also memory
mapped. Read-modify-write operations on the LATD
register read and write the latched output value for
PORTD.
All pins on PORTD are implemented with Schmitt
Trigger
input
buffers.
Each
pin
is
individually
configurable as an input or output.
EXAMPLE 9-4:
INITIALIZING PORTD
Note:
PORTD is only available on 40/44-pin
devices.
Note:
On a Power-on Reset, these pins are
configured as digital inputs.
CLRF
PORTD
; Initialize PORTD by
; clearing output
; data latches
CLRF
LATD
; Alternate method
; to clear output
; data latches
MOVLW
0CFh
; Value used to
; initialize data
; direction
MOVWF
TRISD
; Set RD<3:0> as inputs
; RD<5:4> as outputs
; RD<7:6> as inputs