Datasheet

PIC18(L)F2X/45K50
DS30684A-page 144  2012 Microchip Technology Inc.
11.4 PORTC Registers
PORTC is an 8-bit wide, bidirectional port. The
corresponding data direction register is TRISC. 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).
The Data Latch register (LATC) is also memory
mapped. Read-modify-write operations on the LATC
register read and write the latched output value for
PORTC.
PORTC is multiplexed with several peripheral functions
(Table 11-8). The pins have Schmitt Trigger input buf-
fers.
Some of these pin functions can be relocated to alter-
nate pins using the Control fuse bits in CONFIG3H.
RC0 is the default pin for T3CKI. Clearing the T3CMX
bit moves the pin function to RB5. RC1 is the default pin
for the CCP2 peripheral pin. Clearing the CCP2MX bit
moves the pin function to the RB3 pin.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTC pin. The
EUSART and MSSP peripherals override the TRIS bit
to make a pin an output or an input, depending on the
peripheral configuration. Refer to the corresponding
peripheral section for additional information.
The contents of the TRISC register are affected by
peripheral overrides. Reading TRISC always returns
the current contents, even though a peripheral device
may be overriding one or more of the pins.
EXAMPLE 11-3: INITIALIZING PORTC
11.4.1 PORTC OUTPUT PRIORITY
Each PORTC pin is multiplexed with other functions.
The pins, their combined functions and their output
priorities are briefly described here. For additional
information, refer to the appropriate section in this data
sheet.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the higher priority.
Table 11-4 lists the PORTC pin functions from the
highest to the lowest priority.
Analog input functions, such as ADC, comparator and
SR latch inputs, are not shown in the priority lists.
These inputs are active when the I/O pin is set for
Analog mode using the ANSELx registers. Digital
output functions may control the pin when it is in Analog
mode with the priority shown below.
11.4.2 INTERRUPT-ON-CHANGE
All of the PORTC pins (RC<7:4> and RC<2:0>) are
individually configurable as interrupt-on-change pins.
Control bits in the IOCC register enable (when set) or
disable (when clear) the interrupt function for each pin.
See Section 11.3.2 “Interrupt-On-Change” for
details on operation of interrupt-on-change.
Note: On a Power-on Reset, these pins are
configured as analog inputs.
MOVLB 0xF ; Set BSR for banked SFRs
CLRF LATC ; Initialize PORTC by
; clearing output
; data latches
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISC ; Set RC<3:0> as inputs
; RC<5:4> as outputs
; RC<7:6> as inputs
MOVLW 30h ; Value used to
; enable digital inputs
MOVWF ANSELC ; RC<3:2> dig input enable
; No ANSEL bits for RC<1:0>
; RC<7:6> dig input enable