PIC16LF720_11 Datasheet, PDF (62/244 Pages) Microchip Technology – 20-Pin Flash Microcontrollers with nanoWatt XLP Technology

PIC16(L)F720/721
6.3 PORTC and TRISC Registers
PORTC is a 8-bit wide, bidirectional port. The
corresponding data direction register is TRISC
(Register 6-12). 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 6-3 shows how to initialize PORTC.
Reading the PORTC register (Register 6-11) 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.
The TRISC register (Register 6-12) 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’.
EXAMPLE 6-3: INITIALIZING PORTC
BANKSEL PORTC
CLRF PORTC
BANKSEL TRISC
MOVLW B‘00001100’
MOVWF TRISC
;
;Init PORTC
;
;Set RC<3:2> as inputs
;and set RC<7:4,1:0>
;as outputs
6.3.1 ANSELC REGISTER
The ANSELC register (Register 6-13) 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.
REGISTER 6-11: PORTC: PORTC REGISTER
R/W-x
RC7
bit 7
R/W-x
RC6
R/W-x
RC5
R/W-x
RC4
R/W-x
RC3
R/W-x
RC2
R/W-x
RC1
R/W-x
RC0
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7-0
RC<7:0>: PORTC General Purpose I/O Pin bits
1 = Port pin is > VIH
0 = Port pin is < VIL
DS41430B-page 62
Preliminary
 2011 Microchip Technology Inc.