PIC18F25J11-I/PT MICROCHIP [Microchip Technology], PIC18F25J11-I/PT Datasheet - Page 129

• Manufacturer Part Number: PIC18F25J11-I/PT
• Description: 28/44-Pin, Low-Power, High-Performance Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

9.2
PORTA is a 7-bit wide, bidirectional port. It may
function as a 5-bit port, depending on the oscillator
mode selected. Setting a TRISA bit (= 1) will make the
corresponding PORTA pin an input (i.e., put the
corresponding output driver in a high-impedance
mode). Clearing a TRISA bit (= 0) will make the
corresponding PORTA pin an output (i.e., put the
contents of the output latch on the selected pin).
Reading the PORTA register reads the status of the
pins, whereas writing to it, will write to the port latch.
The Data Latch (LATA) register is also memory mapped.
Read-modify-write operations on the LATA register read
and write the latched output value for PORTA.
The other PORTA pins are multiplexed with analog
inputs, the analog V
parator voltage reference output. The operation of pins,
RA<3:0> and RA5, as A/D converter inputs is selected
by clearing or setting the control bits in the ADCON1
register (A/D Control Register 1).
Pins, RA0 and RA3, may also be used as comparator
inputs and by setting the appropriate bits in the CMCON
register. To use RA<3:0> as digital inputs, it is also
necessary to turn off the comparators.
All PORTA pins have TTL input levels and full CMOS
output drivers.
The TRISA register controls the direction of the PORTA
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.
© 2009 Microchip Technology Inc.
Note:
PORTA, TRISA and LATA Registers
On a Power-on Reset (POR), RA5 and
RA<3:0> are configured as analog inputs
and read as ‘0’.
REF
+ and V
REF
- inputs and the com-
PIC18F46J11 FAMILY
EXAMPLE 9-2:
CLRF
CLRF
MOVLW
MOVWF
MOVWF
MOVWF
MOVLW
MOVWF
PORTA
LATA
07h
ADCON1 ; for digital inputs
07h
CMCON
0CFh
TRISA
; Initialize PORTA by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Configure A/D
; Configure comparators
; for digital input
; Value used to
; initialize data
; direction
; Set RA<3:0> as inputs
; RA<5:4> as outputs
INITIALIZING PORTA
DS39932C-page 129