PIC18F4321 Datasheet, PDF (116/396 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

PIC18F4321 FAMILY
10.4 PORTD, TRISD and LATD
Registers
Note: PORTD is only available on 40/44-pin
devices.
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.
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”.
Note: On a Power-on Reset, these pins are
configured as digital inputs.
PORTD can also be configured as an 8-bit wide micro-
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:
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
CLRF
MOVLW
MOVWF
PORTD
LATD
0CFh
TRISD
; Initialize PORTD by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Value used to
; initialize data
; direction
; Set RD<3:0> as inputs
; RD<5:4> as outputs
; RD<7:6> as inputs
DS39689E-page 114
Preliminary
© 2007 Microchip Technology Inc.