PIC18F258 MICROCHIP [Microchip Technology], PIC18F258 Datasheet - Page 100

• Manufacturer Part Number: PIC18F258
• Description: High Performance, 28/40-Pin Enhanced FLASH Microcontrollers with CAN
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18FXX8
9.3
PORTC is an 8-bit wide, bi-directional port. The corre-
sponding Data Direction register is TRISC. 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.,
put the contents of the output latch on the selected pin).
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 9-5). PORTC pins have Schmitt Trigger input
buffers.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTC pin. Some
peripherals override the TRIS bit to make a pin an output,
FIGURE 9-8:
DS41159B-page 98
Peripheral Enable
Peripheral Out Select
Peripheral Data Out
RD LATC
Data Bus
WR TRISC
RD TRISC
RD PORTC
Peripheral Data In
Note 1: I/O pins have diode protection to V
WR LATC
or
WR PORTC
PORTC, TRISC and LATC Registers
PORTC BLOCK DIAGRAM (PERIPHERAL OUTPUT OVERRIDE)
TRIS Latch
Data Latch
D
D
CK
CK
Q
Q
Q
Q
Override
DD
Preliminary
TRIS
0
1
and V
Q
SS
.
EN
D
while other peripherals override the TRIS bit to make a
pin an input. The user should refer to the corresponding
peripheral section for the correct TRIS bit settings.
The pin override value is not loaded into the TRIS reg-
ister. This allows read-modify-write of the TRIS register,
without concern due to peripheral overrides.
EXAMPLE 9-3:
CLRF
CLRF
MOVLW
MOVWF
Schmitt
Trigger
V
V
N
P
SS
DD
PORTC
LATC
0CFh
TRISC
I/O pin
RC0
RC1
RC2
RC3
RC4
RC5
RC6
RC7
Pin
INITIALIZING PORTC
(1)
; Initialize PORTC by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Value used to
; initialize data
; direction
; Set RC3:RC0 as inputs
; RC5:RC4 as outputs
; RC7:RC6 as inputs
 2002 Microchip Technology Inc.
Override
TRIS OVERRIDE
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Timer1 OSC for
Timer1/Timer3
Timer1 OSC for
Timer1/Timer3
—
SPI/I
Clock
I
SPI Data Out
USART Async
Xmit, Sync Clock
USART Sync
Data Out
2
C Data Out
Peripheral
2
C Master