
PIC18F66K80 FAMILY
DS39977F-page 190
2010-2012 Microchip Technology Inc.
11.8
PORTG, TRISG and
LATG Registers
PORTG is a 5-bit wide, bidirectional port. The
corresponding Data Direction and Output Latch registers
are TRISG and LATG.
PORTG is multiplexed with EUSARTx and CCP, ECCP,
Analog, Comparator and Timer input functions
have Schmitt Trigger input buffers. The open-drain
functionality for the EUARTx can be configured using
ODCON.
Each of the PORTG pins has a weak internal pull-up. A
single control bit can turn off all the pull-ups. This is per-
formed by clearing bit, RGPU (PADCFG1<4>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on any device Reset.
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTG pin. Some
peripherals override the TRIS bit to make a pin an out-
put, 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 register. This allows read-modify-write of the
TRIS register without concern due to peripheral
overrides.
EXAMPLE 11-7:
INITIALIZING PORTG
Note:
PORTG is only available on 64-pin
devices.
CLRF
PORTG
; Initialize PORTG by
; clearing output
; data latches
CLRF
LATG
; Alternate method
; to clear output
; data latches
MOVLW
04h
; Value used to
; initialize data
; direction
MOVWF
TRISG
; Set RG1:RG0 as
; outputs
; RG2 as input
; RG4:RG3 as inputs
TABLE 11-13: PORTG FUNCTIONS
Pin Name
Function
TRIS
Setting
I/O
Type
Description
RG0/RX1/DT1
RG0
0
O
DIG
LATG<0> data output.
1
I
ST
PORTG<0> data input.
RX1
1
I
ST
Asynchronous serial receive data input (EUSARTx module).
DT1
0
O
DIG
Synchronous serial data output (EUSARTx module); takes priority over port data.
1
I
ST
Synchronous serial data input (EUSARTx module); user must configure
as an input.
RG1/CANTX
RG1
0
O
DIG
LATG<1> data output.
1
I
ST
PORTG<1> data input.
CANTX
0
O
DIG
CAN bus TX.
RG2/T3CKI
RG2
0
O
DIG
LATG<2> data output.
1
I
ST
PORTG<2> data input.
x
I
ST
Timer3 clock input.
RG3/TX1/CK1
RG3
0
O
DIG
LATG<3> data output.
1
I
ST
PORTG<3> data input.
TX1
0
O
DIG
Asynchronous serial data output (EUSARTx module); takes priority over port data.
CK1
0
O
DIG
Synchronous serial clock output (EUSARTx module); user must
configure as an input.
1
I
ST
Synchronous serial clock input (EUSARTx module); user must configure
as an input.
RG4/T0CKI
RG4
0
O
DIG
LATG<4> data output.
1
I
ST
PORTG<4> data input.
x
I
ST
Timer0 clock input.
Legend:
O = Output; I = Input; ANA = Analog Signal; DIG = CMOS Output; ST = Schmitt Trigger Buffer Input;
x
= Don’t care (TRIS bit does not affect port direction or is overridden for this option)
Note
1:
This is the alternate pin assignment for T0CKI on 64-pin devices when the T0CKMX Configuration bit is cleared.
2:
This is the default pin assignment for T3CKI on 64-pin devices when the T3CKMX Configuration bit is set.