Datasheet

PIC16(L)F1516/7/8/9
DS41452C-page 116  2010-2012 Microchip Technology Inc.
12.4 PORTC Registers
12.4.1 DATA REGISTER
PORTC is a 8-bit wide bidirectional port. The
corresponding data direction register is TRISC
(Register 12-12). 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).
Example 12-1 shows how to initialize an I/O port.
Reading the PORTC register (Register 12-11) 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).
12.4.2 DIRECTION CONTROL
The TRISC register (Register 12-12) 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’.
12.4.3 ANALOG CONTROL
The ANSELC register (Register 12-14) 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.
12.4.4 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 12-7.
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 list below. 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 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 12-7: PORTC OUTPUT PRIORITY
Pin Name Function Priority
(1)
RC0 SOSCO
RC0
RC1 SOSCI
CCP2
RC1
RC2 CCP1
RC2
RC3 SCL
SCK
RC3
(2)
RC4 SDA
RC4
(2)
RC5 SDO
RC5
RC6 CK
TX
RC6
RC7 DT
RC7
Note 1: Priority listed from highest to lowest.
2: RC3 and RC4 read the I
2
C ST input when
I
2
C mode is enabled.