PIC18F2525 MICROCHIP [Microchip Technology], PIC18F2525 Datasheet - Page 119

• Manufacturer Part Number: PIC18F2525
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

10.5
Depending on the particular PIC18F2525/2620/4525/
4620 device selected, PORTE is implemented in two
different ways.
For 40/44-pin 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., 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.
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.
 2004 Microchip Technology Inc.
Note:
PORTE, TRISE and LATE
Registers
On a Power-on Reset, RE2:RE0 are
configured as analog inputs.
PIC18F2525/2620/4525/4620
Preliminary
The fourth pin of PORTE (MCLR/V
only pin. Its operation is controlled by the MCLRE con-
figuration 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:
10.5.1
For 28-pin devices, PORTE is only available when
Master Clear functionality is disabled (MCLRE = 0). In
these cases, PORTE is a single bit, input only port
comprised of RE3 only. The pin operates as previously
described.
CLRF
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
Note:
PORTE
LATE
0Ah
ADCON1 ; for digital inputs
03h
TRISE
On a Power-on Reset, RE3 is enabled as
a digital input only if Master Clear
functionality is disabled.
PORTE IN 28-PIN DEVICES
; Initialize PORTE by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Configure A/D
; Value used to
; initialize data
; direction
; Set RE<0> as inputs
; RE<1> as outputs
; RE<2> as inputs
INITIALIZING PORTE
PP
DS39626B-page 117
/RE3) is an input