PIC18F2420/2520/4420/4520
PORTD can also be configured as an 8-bit wide micro-
10.4 PORTD, TRISD and LATD
Registers
processor port (Parallel Slave Port) by setting control
bit, PSPMODE (TRISE<4>). In this mode, the input
buffers are TTL. See Section 10.6 “Parallel Slave
Port” for additional information on the Parallel Slave
Port (PSP).
Note:
PORTD is only available on 40/44-pin
devices.
PORTD is an 8-bit wide, bidirectional port. The corre-
sponding 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).
Note:
When the enhanced PWM mode is used
with either dual or quad outputs, the PSP
functions of PORTD are automatically
disabled.
EXAMPLE 10-4:
INITIALIZING PORTD
CLRF
PORTD
; Initialize PORTD by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Value used to
; initialize data
; direction
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.
CLRF
LATD
All pins on PORTD are implemented with Schmitt Trig-
ger input buffers. Each pin is individually configurable
as an input or output.
MOVLW
MOVWF
0CFh
Three of the PORTD pins are multiplexed with outputs
P1B, P1C and P1D of the Enhanced CCP module. The
operation of these additional PWM output pins is
covered in greater detail in Section 16.0 “Enhanced
Capture/Compare/PWM (ECCP) Module”.
TRISD
; Set RD<3:0> as inputs
; RD<5:4> as outputs
; RD<7:6> as inputs
Note:
On a Power-on Reset, these pins are
configured as digital inputs.
DS39631E-page 114
© 2008 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
