PIC18F47J53 Datasheet, PDF (158/586 Pages) Microchip Technology – 28/44-Pin, High-Performance USB Microcontrollers with nanoWatt XLP Technology

PIC18F47J53 FAMILY
10.6 PORTE, TRISE and LATE
Registers
Note: PORTE is available only in 44-pin devices.
Depending on the particular PIC18F47J53 family
device selected, PORTE is implemented in two
different ways.
For 44-pin devices, PORTE is a 3-bit wide port. Three
pins (RE0/AN5/PMRD, RE1/AN6/PMWR and RE2/
AN7/PMCS) are individually configurable as inputs or
outputs. These pins have Schmitt Trigger input buffers.
When selected as analog inputs, these pins will read as
‘0’s.
The corresponding Data Direction register is TRISE.
Setting a TRISE bit (= 1) will make the corresponding
PORTE pin an input (i.e., put the corresponding output
driver in a High-Impedance mode). Clearing a TRISE
bit (= 0) will make the corresponding PORTE pin an
output (i.e., put the contents of the output latch on the
selected pin).
TRISE controls the direction of the RE pins, even when
they are being used as analog inputs. The user must
make sure to keep the pins configured as inputs when
using them as analog inputs.
Note: On a POR, RE<2:0> are configured as
analog inputs.
The Data Latch register (LATE) is also memory
mapped. Read-modify-write operations on the LATE
register read and write the latched output value for
PORTE.
EXAMPLE 10-6: INITIALIZING PORTE
CLRF
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
PORTE
LATE
0Ah
ADCON1
03h
TRISE
; Initialize PORTE by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Configure A/D
; for digital inputs
; Value used to
; initialize data
; direction
; Set RE<0> as inputs
; RE<1> as outputs
; RE<2> as inputs
Each of the PORTE pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is per-
formed by setting bit, REPU (TRISE<6>). The weak
pull-up is automatically turned off when the port pin is
configured as an output. The pull-ups are disabled on a
POR. The integrated weak pull-ups consist of a semi-
conductor structure similar to, but somewhat different,
from a discrete resistor. On an unloaded I/O pin, the
weak pull-ups are intended to provide logic high indica-
tion, but will not necessarily pull the pin all the way to
VDD levels.
Note that the pull-ups can be used for any set of
features, similar to the pull-ups found on PORTB.
DS39964B-page 158
Preliminary
 2010 Microchip Technology Inc.