Microchip Technology MA180025 Data Sheet
PIC18F87J90 FAMILY
DS39933D-page 128
2010 Microchip Technology Inc.
10.6
PORTE, TRISE and
LATE Registers
LATE Registers
PORTE is a 7-bit wide, bidirectional port. The
corresponding Data Direction and Output Latch registers
are TRISE and LATE. All pins on PORTE are digital only
and tolerate voltages up to 5.5V.
All pins on PORTE are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output. The RE7 pin is also
configurable for open-drain output when CCP2 is active
on this pin. Open-drain configuration is selected by
setting the CCP2OD control bit (TRISG<6>)
corresponding Data Direction and Output Latch registers
are TRISE and LATE. All pins on PORTE are digital only
and tolerate voltages up to 5.5V.
All pins on PORTE are implemented with Schmitt
Trigger input buffers. Each pin is individually
configurable as an input or output. The RE7 pin is also
configurable for open-drain output when CCP2 is active
on this pin. Open-drain configuration is selected by
setting the CCP2OD control bit (TRISG<6>)
Each of the PORTE pins has a weak internal pull-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.
Pins, RE<6:3>, are multiplexed with the LCD common
drives. I/O port functions are only available on those
PORTE pins depending on which commons are active.
The configuration is determined by the LMUX<1:0>
control bits (LCDCON<1:0>). The availability is
summarized in Table 10-11.
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.
Pins, RE<6:3>, are multiplexed with the LCD common
drives. I/O port functions are only available on those
PORTE pins depending on which commons are active.
The configuration is determined by the LMUX<1:0>
control bits (LCDCON<1:0>). The availability is
summarized in Table 10-11.
TABLE 10-11: PORTE PINS AVAILABLE IN
DIFFERENT LCD DRIVE
CONFIGURATIONS
CONFIGURATIONS
Pins, RE1 and RE0, are multiplexed with the functions
of LCDBIAS2 and LCDBIAS1. When LCD bias genera-
tion is required (i.e., any application where the device
is connected to an external LCD), these pins cannot be
used as digital I/O.
of LCDBIAS2 and LCDBIAS1. When LCD bias genera-
tion is required (i.e., any application where the device
is connected to an external LCD), these pins cannot be
used as digital I/O.
RE7 is multiplexed with the LCD segment drive
(SEG31) controlled by the LCDSE3<7> bit. I/O port
function is only available when the segment is disabled.
RE7 can also be configured as the alternate peripheral
pin for the CCP2 module. This is done by clearing the
CCP2MX Configuration bit.
(SEG31) controlled by the LCDSE3<7> bit. I/O port
function is only available when the segment is disabled.
RE7 can also be configured as the alternate peripheral
pin for the CCP2 module. This is done by clearing the
CCP2MX Configuration bit.
EXAMPLE 10-5:
INITIALIZING PORTE
Note:
These pins are configured as digital inputs
on any device Reset.
on any device Reset.
LCDCON
<1:0>
Active LCD
Commons
PORTE Available
for I/O
00
COM0
RE6, RE5, RE4
01
COM0, COM1
RE6, RE5
10
COM0, COM1
and COM2
RE6
11
All (COM0
through COM3)
None
Note:
The pin corresponding to RE2 of other
PIC18F parts has the function of
LCDBIAS3 in this device. It cannot be used
as digital I/O.
PIC18F parts has the function of
LCDBIAS3 in this device. It cannot be used
as digital I/O.
CLRF
PORTE
; Initialize PORTE by
; clearing output
; data latches
CLRF
LATE
; Alternate method
; to clear output
; data latches
MOVLW
03h
; Value used to
; initialize data
; direction
MOVWF
TRISE
; Set RE<1:0> as inputs
; RE<7:2> as outputs