PIC18F87J10 Datasheet, PDF (129/394 Pages) Microchip Technology – 64/80-Pin High-Performance, 1-Mbit Flash Microcontrollers with nanoWatt Technology

PIC18F87J10 FAMILY
10.6 PORTE, TRISE and
LATE Registers
PORTE is a 7-bit wide, bidirectional port. The corre-
sponding 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).
All pins on PORTE are digital only and tolerate voltages
up to 5.5V.
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.
All pins on PORTE are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output.
Note: These pins are configured as digital inputs
on any device Reset.
On 80-pin devices, PORTE is multiplexed with the
system bus as part of the external memory interface.
I/O port and other functions are only available when the
interface is disabled, by setting the EBDIS bit
(MEMCON<7>). When the interface is enabled,
PORTE is the high-order byte of the multiplexed
address/data bus (AD15:AD8). The TRISE bits are also
overridden.
Each of the PORTE pins has a weak internal pull-up.
The pull-ups are provided to keep the inputs at a known
state for the external memory interface while powering
up. A single control bit can turn off all the pull-ups. This
is performed by clearing bit REPU (PORTG<6>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on any device Reset.
PORTE is also multiplexed with Enhanced PWM
outputs B and C for ECCP1 and ECCP3 and outputs B,
C and D for ECCP2. For all devices, their default
assignments are on PORTE<6:3>. On 80-pin devices,
the multiplexing for the outputs of ECCP1 and ECCP3
is controlled by the ECCPMX configuration bit. Clearing
this bit reassigns the P1B/P1C and P3B/P3C outputs to
PORTH.
For devices operating in Microcontroller mode, pin RE7
can be configured as the alternate peripheral pin for the
ECCP2 module and Enhanced PWM output 2A. This is
done by clearing the CCP2MX configuration bit.
When the Parallel Slave Port is active on PORTD, three
of the PORTE pins (RE0, RE1 and RE2) are configured
as digital control inputs for the port. The control
functions are summarized in Table 10-11. The reconfig-
uration occurs automatically when the PSPMODE
control bit (PSPCON<4>) is set. Users must still make
certain the corresponding TRISE bits are set to
configure these pins as digital inputs.
EXAMPLE 10-5: INITIALIZING PORTE
CLRF
CLRF
MOVLW
MOVWF
PORTE
LATE
03h
TRISE
; Initialize PORTE by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Value used to
; initialize data
; direction
; Set RE<1:0> as inputs
; RE<7:2> as outputs
 2005 Microchip Technology Inc.
Advance Information
DS39663A-page 127