XRT79L71_1 Datasheet, PDF (45/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

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XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
BIT NUMBER
NAME
0
General Purpose Data[0]
TYPE
R/W
DESCRIPTION
General Purpose Data - GPIO_0:
The exact function of this bit-field depends upon whether Gen-
eral Purpose I/O Pin, GPIO_0 (Pin T7) has been configured to
function as an input or an output pin, as described below.
If GPIO_0 is configured to function as an input pin
If GPIO_0 is configured to function as an input pin, then the user
can monitor the state of this particular input pin by reading out
the state of this bit-field.
If this bit-field is set to "0" then it means that GPIO_0 is currently
pulled to a logic "Low" level. Conversely, if this bit-field is set to
"1", then it means that GPIO_0 is currently pulled to a logic
"High" level.
NOTE: If GPIO_0 is configured to function as an input pin, then
writing to this particular register will have no affect on the
state of this pin.
If GPIO_0 is configured to function as an output pin
If GPIO_0 is configured to function as an output pin, then the
user can control the state of this particular output pin by writing
the appropriate value to this bit-field.
Setting this bit-field to "0" will cause GPIO_0 to be driven to a
logic "Low" level. Conversely, setting this bit-field to "1" will
cause GPIO_0 to be driven to a logic "High" level.
NOTE: GPIO_0 can be configured to function as either an input
or output pin, by writing the appropriate value to Bit 0
(General Purpose Pin Direction[0]) within the "Operation
General Purpose Pin Direction Control" Register
(Address = 0x014B).
Operation General Purpose Pin Direction Control Register (Address = 0x014B)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
General
General
General
General
Purpose Pin Purpose Pin Purpose Pin Purpose Pin
Direction [3] Direction [2] Direction [1] Direction [0]
R/O
R/W
R/W
R/W
R/W
0
0
0
0
0
BIT NUMBER
NAME
7 -4
Unused
TYPE
R/O
DESCRIPTION
36