Datasheet

PIC18F6390/6490/8390/8490

9.8 PORTH, LATH and

TRISH Registers

PORTH is an 8-bit wide, bidirectional I/O port. The cor-

responding Data Direction register is TRISH. Setting a

TRISH bit (= 1) will make the corresponding PORTH

pin an input (i.e., put the corresponding output driver in

a high-impedance mode). Clearing a TRISH bit (= 0)

will make the corresponding PORTH pin an output (i.e.,

put the contents of the output latch on the selected pin).

The Data Latch register (LATH) is also memory

mapped. Read-modify-write operations on the LATH

PORTH.

All pins on PORTH are implemented with Schmitt

Trigger input buffers. Each pin is individually

configurable as an input or output.

PORTH is also multiplexed with LCD segment drives

controlled by the LCDSE5 register. I/O port functions

are only available when the segments are disabled.

EXAMPLE 9-8: INITIALIZING PORTH

Note: PORTH is available only on 80-pin

devices.

Note: On a Power-on Reset, these pins are

configured as digital inputs.

CLRF PORTH ; Initialize PORTH by

; clearing output

; data latches

CLRF LATH ; Alternate method

; to clear output

; data latches

MOVLW 0CFh ; Value used to

; initialize data

; direction

MOVWF TRISH ; Set RH3:RH0 as inputs

; RH5:RH4 as outputs

; RH7:RH6 as inputs