Datasheet

© 2009 Microchip Technology Inc. DS41341E-page 73
PIC16F72X/PIC16LF72X
6.4 PORTC and TRISC Registers
PORTC is a 8-bit wide, bidirectional port. The
corresponding data direction register is TRISC
(Register 6-11). 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 6-10) 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 6-11) 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
The location of the CCP2 function is controlled by the
CCP2SEL bit in the APFCON register (refer to
Register 6-1)
BANKSEL PORTC ;
CLRF PORTC ;Init PORTC
BANKSEL TRISC ;
MOVLW B‘00001100’ ;Set RC<3:2> as inputs
MOVWF TRISC ;and set RC<7:4,1:0>
;as outputs
REGISTER 6-10: PORTC: PORTC REGISTER
R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x R/W-x
RC7 RC6 RC5 RC4 RC3 RC2 RC1 RC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘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 > V
IH
0 = Port pin is < VIL
REGISTER 6-11: TRISC: PORTC TRI-STATE REGISTER
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
TRISC7 TRISC6 TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 TRISC<7:0>: PORTC Tri-State Control bits
1 = PORTC pin configured as an input (tri-stated)
0 = PORTC pin configured as an output