Microchip Technology DM164130-2 Data Sheet
PIC16(L)F1946/47
DS41414D-page 142
2010-2012 Microchip Technology Inc.
12.11 PORTE Registers
PORTE is an 8-bit wide, bidirectional port. 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.,
enable the output driver and put the contents of the
output latch on the selected pin).
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.,
enable the output driver and put the contents of the
output latch on the selected pin).
shows
how to initialize an I/O port.
Reading the PORTE register (
Reading the PORTE register (
) reads
the status of the pins, whereas writing to it will write to
the PORT latch. All write operations are
read-modify-write operations. Therefore, a write to a
port implies that the port pins are read, this value is
modified and then written to the PORT data latch
(LATE).
the PORT latch. All write operations are
read-modify-write operations. Therefore, a write to a
port implies that the port pins are read, this value is
modified and then written to the PORT data latch
(LATE).
12.11.1
ANSELE REGISTER
The ANSELE register (
) is used to
configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELE bit high will cause all
digital reads on the pin to be read as ‘0’ and allow
analog functions on the pin to operate correctly.
The state of the ANSELE bits has no effect on digital
output functions. A pin with TRIS clear and ANSEL set
will still operate as a digital output, but the Input mode
will be analog. This can cause unexpected behavior
when executing read-modify-write instructions on the
affected port.
The TRISE register (
Setting the appropriate ANSELE bit high will cause all
digital reads on the pin to be read as ‘0’ and allow
analog functions on the pin to operate correctly.
The state of the ANSELE bits has no effect on digital
output functions. A pin with TRIS clear and ANSEL set
will still operate as a digital output, but the Input mode
will be analog. This can cause unexpected behavior
when executing read-modify-write instructions on the
affected port.
The TRISE register (
) controls the PORTE
pin output drivers, even when they are being used as
analog inputs. The user should ensure the bits in the
TRISE register are maintained set when using them as
analog inputs. I/O pins configured as analog inputs
always read ‘0’.
analog inputs. The user should ensure the bits in the
TRISE register are maintained set when using them as
analog inputs. I/O pins configured as analog inputs
always read ‘0’.
12.11.2
PORTE FUNCTIONS AND OUTPUT
PRIORITIES
PRIORITIES
Each PORTE pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are shown in
pins, their combined functions and their output priorities
are shown in
.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the highest priority.
Each PORTE pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are briefly described here. For additional information,
refer to the appropriate section in this data sheet.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the lowest number in
the following lists.
Analog input and some digital input functions are not
included in the list below. These input functions can
remain active when the pin is configured as an output.
Certain digital input functions, such as the EUSART RX
signal, override other port functions and are included in
the priority list.
control goes to the peripheral with the highest priority.
Each PORTE pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are briefly described here. For additional information,
refer to the appropriate section in this data sheet.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the lowest number in
the following lists.
Analog input and some digital input functions are not
included in the list below. These input functions can
remain active when the pin is configured as an output.
Certain digital input functions, such as the EUSART RX
signal, override other port functions and are included in
the priority list.
Note:
The ANSELE register must be initialized
to configure an analog channel as a digital
input. Pins configured as analog inputs
will read ‘0’.
to configure an analog channel as a digital
input. Pins configured as analog inputs
will read ‘0’.
TABLE 12-11: PORTE OUTPUT PRIORITY
Pin Name
Function Priority
(1)
RE0
P2D
(2)
(CCP)
RE0
RE1
P2C
(2)
(CCP)
RE1
RE2
P2B
(2)
(CCP)
RE2
RE3
P3C
(2)
(CCP)
COM0 (LCD)
RE3
RE3
RE4
P3B
(2)
(CCP)
COM1 (LCD)
RE4
RE4
RE5
P1C
(2)
(CCP)
COM32(LCD)
RE5
RE5
RE6
P1B
(2)
(CCP)
COM3 (LCD)
RE6
RE6
RE7
CCP2
(3)
/P2A
(3)
(CCP)
SEG31 (LCD)
RE7
RE7
Note 1: Priority listed from highest to lowest.
2:
Default pin (see APFCON register).
3:
Alternate pin (see APFCON register).