Datasheet

© 2008 Microchip Technology Inc. DS39646C-page 149
PIC18F8722 FAMILY
11.6 PORTF, LATF and TRISF Registers
PORTF is an 8-bit wide, bidirectional port. The corre-
sponding Data Direction register is TRISF. Setting a
TRISF bit (= 1) will make the corresponding PORTF pin
an input (i.e., put the corresponding output driver in a
high-impedance mode). Clearing a TRISF bit (= 0) will
make the corresponding PORTF pin an output (i.e., put
the contents of the output latch on the selected pin).
The Data Latch register (LATF) is also memory
mapped. Read-modify-write operations on the LATF
register read and write the latched output value for
PORTF.
All pins on PORTF are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output.
PORTF is multiplexed with several analog peripheral
functions, including the A/D converter and comparator
inputs, as well as the comparator outputs. Pins RF1
through RF2 may be used as comparator inputs or
outputs by setting the appropriate bits in the CMCON
register. To use RF<6:0:> as digital inputs, it is
necessary to turn off the A/D inputs.
EXAMPLE 11-6: INITIALIZING PORTF
Note 1: On a Power-on Reset, the RF<6:0> pins
are configured as analog inputs and read
as ‘0’.
2: To configure PORTF as digital I/O, set the
ADCON1 register.
CLRF PORTF ; Initialize PORTF by
; clearing output
; data latches
CLRF LATF ; Alternate method
; to clear output
; data latches
MOVLW 0x0F ;
MOVWF ADCON1 ; Set PORTF as digital I/O
MOVLW 0xCF ; Value used to
; initialize data
; direction
MOVWF TRISF ; Set RF3:RF0 as inputs
; RF5:RF4 as outputs
; RF7:RF6 as inputs