XRT83VSH28
PRELIMINARY
8-CHANNEL E1 SHORT-HAUL LINE INTERFACE UNIT
FUNCTIONAL DESCRIPTION
REV. P1.0.0
The XRT83VSH28 is a fully integrated 8-channel short-haul line interface unit (LIU) that operates from a 1.8V
and a 3.3V power supply. The LIU features are programmed through a standard microprocessor interface or
controlled through Hardware mode. EXAR’s LIU has patented high impedance circuits that allow the
transmitter outputs and receiver inputs to be high impedance when experiencing a power failure or when the
LIU is powered off. Key design features within the LIU optimize 1:1 or 1+1 redundancy and non-intrusive
monitoring applications to ensure reliability without using relays. Additional features include RLOS, a 16-bit
LCV counter for each channel, AIS, QRSS generation/detection, Network Loop Code generation/detection,
TAOS, DMO, and diagnostic loopback modes.
1.0 HARDWARE MODE VS HOST MODE
The LIU supports a parallel or serial microprocessor interface (Host mode) for programming the internal
features, or a Hardware mode that can be used to configure the device.
1.1 Feature Differences in Hardware Mode
Some features within the Hardware mode are not supported on a per channel basis. The differences between
Hardware mode and Host mode are descibed below in Table 1.
TABLE 1: DIFFERENCES BETWEEN HARDWARE MODE AND HOST MODE
FEATURE
HOST MODE
HARDWARE MODE
Tx Test Patterns
Fully Supported
QRSS diagnostic patterns are not available in Hardware mode.
The TAOS feature is available.
RxRES[1:0]
Per Channel
In Hardware mode, RxRES[1:0] is a global setting that applies to
all channels.
TERSEL[1:0]
Per Channel
In Hardware mode, TERSEL[1:0] is a global setting that applies to
all channels.
EQC[4:0]
Per Channel
In Hardware mode, the EQC[4:0] is a global setting that applies to
all channels.
Dual Loopback
Fully Supported
In Hardware mode, dual loopback mode is not supported.
Remote, Analog local, and digital loopback modes are available.
JASEL[1:0]
Per Channel
In Hardware mode, the jitter attenuator selection is a global setting
that applies to all channels.
RxTSEL
Per Channel
In Hardware mode, the receive termination select is a global set-
ting that applies to all channels.
TxTSEL
Per Channel
In Hardware mode, the transmit termination select is a global set-
ting that applies to all channels.
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