XRT91L80_0507 Datasheet, PDF (38/45 Pages) Exar Corporation – 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER

XRT91L80
PRELIMINARY
2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER
xr
REV. P1.1.0
DIAGNOSTIC CONTROL REGISTER (0X05H)
BIT
NAME
FUNCTION
Register
Type
Default
Value
(HW reset)
D5
Reserved This Register Bit is Not Used
X
X
D4
Reserved This Register Bit is Not Used
X
X
D3
Reserved This Register Bit is Not Used
X
X
D2
DLOOP Digital Local Loopback
R/W
0
Digital local loopback allows the transmit input pins to be looped
back to the receive output pins for local diagnostics. The transmit
serial data output is valid during the digital loopback.
"0" = Disabled
"1" = Enable Digital Local Loopback
NOTE: DLOOP and RLOOPS can be enabled simultaneously to
achieve a dual loopback diagnostic feature.
D1
RLOOPS Serial Remote Loopback
R/W
0
Serial remote loopback allows the receive serial input pins to be
looped back to the transmit serial output pins for remote diagnos-
tics. The receive data output is valid during a serial remote loop-
back.
"0" = Disabled
"1" = Enable Remote Serial Loopback
NOTE: DLOOP and RLOOPS can be enabled simultaneously to
achieve a dual loopback diagnostic feature.
D0
RLOOPP Parallel Remote Loopback
R/W
0
Parallel remote loopback has the same affect as the serial remote
loopback, except that the data input is allowed to pass through the
SIPO before it’s looped back to the transmit path, wherein it
passes through the transmit FIFO, through the PISO, and back out
the transmit serial output. The receive data output is valid during a
parallel remote loopback.
"0" = Disabled
"1" = Enable Remote Parallel Loopback
NOTE: DLOOP and RLOOPS should be disabled when RLOOPP
is enabled. The internal FIFO should also be flushed using
FIFO_RST when parallel remote loopback is enabled/
disabled.
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