PIC18F23K20-E/MLQTP MICROCHIP [Microchip Technology], PIC18F23K20-E/MLQTP Datasheet - Page 131

• Manufacturer Part Number: PIC18F23K20-E/MLQTP
• Description: 28/40/44-Pin Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

10.6
Depending on the particular PIC18F2XK20/4XK20
device selected, PORTE is implemented in two
different ways.
10.6.1
For PIC18F4XK20 devices, PORTE is a 4-bit wide port.
Three pins (RE0/RD/AN5, RE1/WR/AN6 and RE2/CS/
AN7) are individually configurable as inputs or outputs.
These pins have Schmitt Trigger input buffers. When
selected as an analog input, 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., disable the output driver).
Clearing a TRISE bit (= 0) will make the corresponding
PORTE pin an output (i.e., enable the output driver and
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.
The upper four bits of the TRISE register also control
the operation of the Parallel Slave Port. Their operation
is explained in Register 10-1.
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.
© 2007 Microchip Technology Inc.
Note:
PORTE, TRISE and LATE
Registers
PORTE IN PIC18F4XK20 DEVICES
On a Power-on Reset, RE<2:0> are
configured as analog inputs.
Advance Information
The fourth pin of PORTE (MCLR/V
only pin. Its operation is controlled by the MCLRE
Configuration bit. When selected as a port pin
(MCLRE = 0), it functions as a digital input only pin; as
such, it does not have TRIS or LAT bits associated with its
operation. Otherwise, it functions as the device’s Master
Clear input. In either configuration, RE3 also functions as
the programming voltage input during programming.
EXAMPLE 10-5:
10.6.2
For PIC18F2XK20 devices, PORTE is only available
when
(MCLR = 0). In these cases, PORTE is a single bit,
input only port comprised of RE3 only. The pin operates
as previously described.
PIC18F2XK20/4XK20
CLRF
CLRF
MOVLW
ANDWF
MOVLW
MOVWF
Note:
Master
PORTE
LATE
1Fh
ANSEL,w ; for digital only
05h
TRISE
On a Power-on Reset, RE3 is enabled as
a digital input only if Master Clear
functionality is disabled.
PORTE IN PIC18F2XK20 DEVICES
Clear
; Initialize PORTE by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Configure analog pins
; Value used to
; initialize data
; direction
; Set RE<0> as input
; RE<1> as output
; RE<2> as input
INITIALIZING PORTE
functionality
PP
DS41303B-page 129
/RE3) is an input
is
disabled