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XRT83SL28
REV. 1.0.0
8-CHANNEL E1 SHORT-HAUL LINE INTERFACE UNIT
PIN DESCRIPTIONS
HOST MODE INTERFACE
SERIAL MICROPROCESSOR INTERFACE
NAME
PIN
TYPE
DESCRIPTION
CS
89
I
Chip Select Input
Active low signal. This signal enables the serial microprocessor interface by
pulling chip select "Low". The serial interface is disabled when the chip select
signal returns "High".
SCLK
SDI
90
92
91
28
I
I
Serial Clock Input
The serial clock input samples SDI on the rising edge and updates SDO on the
falling edge. See the Serial Microprocessor section of this datasheet for more
details.
Serial Data Input
The serial data input pin is used to supply an address and data string to pro-
gram the internal registers within the device. See the Serial Microprocessor
section of this datasheet for more details.
SDO
Reset
O
I
Serial Data Output
The serial data output pin is used to retrieve the internal contents of a selected
register in readback mode. See the Microprocessor section of this datasheet
for more details.
Hardware Reset Input
Active low signal. When this pin is pulled "Low" for more than 10µS, all internal
registers and state machines are set to their default state.
NOTE: This pin must be pulled "High" to VDD for normal operation.
INT
100
O
Interrupt Output
Active low signal. This signal is asserted "Low" when a change in alarm status
occurs. Once the status registers have been read, the interrupt pin will return
"High". GIE (Global Interrupt Enable) must be set "High" in the appropriate
global register to enable interrupt generation.
NOTE: This pin is an open-drain output that requires an external 10KΩ pull-up
resistor.
HW/Host
81
I
Hardware / Host Mode Select Input
This pin is used to select the mode of operation. By default, the LIU is config-
ured for Host mode. To select Hardware mode, this pin must be pulled "High".
NOTE: Internally pulled "Low" with a 50kΩ resistor.
5
EXAR [ EXAR CORPORATION ]
