PIC16F7X
4.3
PORTC and the TRISC Register
FIGURE 4-5:
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 Hi-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).
PORTC is multiplexed with several peripheral functions
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, while other peripherals override the TRIS bit to
make a pin an input. Since the TRIS bit override is
in effect while the peripheral is enabled,
read-modify-write instructions (BSF,
BCF, XORWF)
with TRISC as destination should be avoided. The user
should refer to the corresponding peripheral section for
the correct TRIS bit settings, and to Section 13.1 for
additional information on read-modify-write operations.
WR TRIS
PORTC BLOCK DIAGRAM
(PERIPHERAL OUTPUT
OVERRIDE)
Port/Peripheral Select
(2)
Peripheral Data Out
Data Bus
WR Port
D
CK
Q
1
Q
Data Latch
D
CK
Q
Q
N
V
SS
RD TRIS
Peripheral
OE
(3)
Q
D
EN
RD Port
Peripheral Input
Note 1:
I/O pins have diode protection to V
DD
and V
SS
.
2:
Port/Peripheral select signal selects between port data
and peripheral output.
3:
Peripheral OE (output enable) is only activated if
peripheral select is active.
Schmitt
Trigger
I/O
pin
(1)
V
DD
P
0
TRIS Latch
TABLE 4-5:
Name
PORTC FUNCTIONS
Bit#
bit0
bit1
bit2
bit3
bit4
bit5
bit6
bit7
Buffer Type
ST
ST
ST
ST
ST
ST
ST
ST
Function
Input/output port pin or Timer1 oscillator output/Timer1 clock input.
Input/output port pin or Timer1 oscillator input or Capture2
input/Compare2 output/PWM2 output.
Input/output port pin or Capture1 input/Compare1 output/PWM1 output.
RC3 can also be the synchronous serial clock for both SPI and I
2
C
modes.
RC4 can also be the SPI Data In (SPI mode) or Data I/O (I
2
C mode).
Input/output port pin or Synchronous Serial Port data output.
Input/output port pin or USART Asynchronous Transmit or
Synchronous Clock.
Input/output port pin or USART Asynchronous Receive or
Synchronous Data.
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
Legend: ST = Schmitt Trigger input
TABLE 4-6:
Address
07h
87h
SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Bit 7
RC7
Bit 6
RC6
Bit 5
RC5
Bit 4
RC4
Bit 3
RC3
Bit 2
RC2
Bit 1
RC1
Bit 0
RC0
Value on:
POR,
BOR
Value on
all other
RESETS
Name
PORTC
TRISC
xxxx xxxx uuuu uuuu
1111 1111 1111 1111
PORTC Data Direction Register
Legend:
x
= unknown,
u
= unchanged
2002 Microchip Technology Inc.
DS30325B-page 35
MICROCHIP [ MICROCHIP TECHNOLOGY ]
