Microchip Technology AC244049 Data Sheet
PIC16(L)F1825/1829
DS41440C-page 134
2010-2012 Microchip Technology Inc.
12.4
PORTC Registers
PORTC is a 6-bit wide (8-bit wide for PIC16(L)F1829),
bidirectional port. The corresponding data direction
register is TRISC (
bidirectional port. The corresponding data direction
register is TRISC (
). Setting a TRISC bit
(= 1) will make the corresponding PORTC pin an input
(i.e., put the corresponding output driver in a
High-Impedance mode). Clearing a TRISC bit (= 0) will
make the corresponding PORTC pin an output (i.e.,
enable the output driver and put the contents of the
output latch on the selected pin).
(i.e., put the corresponding output driver in a
High-Impedance mode). Clearing a TRISC bit (= 0) will
make the corresponding PORTC 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 a port.
Reading the PORTC register (
Reading the PORTC 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 (LATC).
The TRISC register (
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 (LATC).
The TRISC register (
) controls the
PORTC pin output drivers, even when they are being
used as analog inputs. The user should ensure the bits in
the TRISC register are maintained set when using them
as analog inputs. I/O pins configured as analog input
always read ‘0’.
The INLVLC register (
used as analog inputs. The user should ensure the bits in
the TRISC register are maintained set when using them
as analog inputs. I/O pins configured as analog input
always read ‘0’.
The INLVLC register (
) controls the input
voltage threshold for each of the available PORTC
input pins. A selection between the Schmitt Trigger
CMOS or the TTL Compatible thresholds is available.
The input threshold is important in determining the
value of a read of the PORTC register and also the
level at which an Interrupt-on-Change occurs, if that
feature is enabled. See
input pins. A selection between the Schmitt Trigger
CMOS or the TTL Compatible thresholds is available.
The input threshold is important in determining the
value of a read of the PORTC register and also the
level at which an Interrupt-on-Change occurs, if that
feature is enabled. See
for more information
on threshold levels.
12.4.1
ANSELC REGISTER
The ANSELC register (
) is used to
configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELC 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 ANSELC bits has no effect on digital
output functions. A pin with TRIS clear and ANSELC 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.
Setting the appropriate ANSELC 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 ANSELC bits has no effect on digital
output functions. A pin with TRIS clear and ANSELC 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.
Note:
Changing the input threshold selection
should be performed while all peripheral
modules are disabled. Changing the
threshold level during the time a module is
active may inadvertently generate a
transition associated with an input pin,
regardless of the actual voltage level on
that pin.
should be performed while all peripheral
modules are disabled. Changing the
threshold level during the time a module is
active may inadvertently generate a
transition associated with an input pin,
regardless of the actual voltage level on
that pin.
Note:
The ANSELC bits default to the Analog
mode after Reset. To use any pins as
digital general purpose or peripheral
inputs, the corresponding ANSEL bits
must be initialized to ‘0’ by user software.
mode after Reset. To use any pins as
digital general purpose or peripheral
inputs, the corresponding ANSEL bits
must be initialized to ‘0’ by user software.