Datasheet

 2011-2013 Microchip Technology Inc. DS40001609C-page 119
PIC16(L)F1508/9
11.7 PORTC Registers
11.7.1 DATA REGISTER
PORTC is a 8-bit wide, bidirectional port. The
corresponding data direction register is TRISC
(Register 11-13). Setting a TRISC bit (= 1) will make
the corresponding PORTC pin an input (i.e., disable
the output driver). 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). Example 11-1 shows how to
initialize an I/O port.
Reading the PORTC register (Register 11-12) 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).
11.7.2 DIRECTION CONTROL
The TRISC register (Register 11-13) 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’.
11.7.3 ANALOG CONTROL
The ANSELC register (Register 11-15) 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 out-
put 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 exe-
cuting read-modify-write instructions on the affected
port.
11.7.4 PORTC FUNCTIONS AND OUTPUT
PRIORITIES
Each PORTC pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are shown in Table 11-8.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the highest priority.
Analog input and some digital input functions are not
included in the output priority list. These input functions
can remain active when the pin is configured as an
output. Certain digital input functions override other
port functions and are included in the output priority list.
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.
TABLE 11-8: PORTC OUTPUT PRIORITY
Pin Name Function Priority
(1)
RC0 CLC2
RC0
RC1 NCO1
(2)
PWM4
RC1
RC2 RC2
RC3 PWM2
RC3
RC4 CWG1B
CLC4
C2OUT
RC4
RC5 CWG1A
CLC1
(3)
PWM1
RC5
RC6 NCO1
(3)
RC6
RC7 SDO
RC7
Note 1: Priority listed from highest to lowest.
2: Default pin (see APFCON register).
3: Alternate pin (see APFCON register).