XRT73LC03A Datasheet, PDF (57/61 Pages) Exar Corporation – 3 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT

XRT73LC03A
3 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT
REV. 1.0.1
Bit D4 - SR/DR_(n) (Single-Rail/Dual-Rail Data
Output - Channel(n))/(B3ZS/HDB3 Encoder/De-
coder-Disable - Channel(n))
This Read/Write bit-field is used to configure Chan-
nel(n) to output the received data from the Remote
Terminal in a binary or Dual-Rail format and Enable or
Disable the B3ZS/HDB3 Encoder and Decoder
blocks.
Writing a "1" to this bit-field enables the B3ZS/HDB3
Encoder and Decoder blocks. Writing a "0" to this bit-
field disables the B3ZS/HDB3 Encoder and Decoder
blocks.
NOTE: This Encoder/Decoder performs HDB3 Encoding/
Decoding if the XRT73LC03A is operating in the E3 Mode.
Otherwise, it performs B3ZS Encoding/Decoding.
.Writing a "1" to this bit-field also configures Chan-
nel(n) to output data to the Terminal Equipment in a
binary (Single-Rail) format via the RPOS_(n) output
pin, RNEG_(n) is grounded. Writing a "0" to this bit-
field configures Channel(n) to output data to the Ter-
minal Equipment in a Dual-Rail format via both the
RPOS_(n) and RNEG_(n) output pins.
Bit D3 - LOSMUT_(n) (Recovered Data Muting,
during LOS Condition - Channel(n))
This Read/Write bit-field is used to configure Chan-
nel(n) to not output any recovered data from the line
while it is declaring an LOS condition.
Writing a "0" to this bit-field configures the chip to out-
put recovered data even while the XRT73LC03A is
declaring an LOS condition. Writing a "1" to this bit-
field configures the chip to NOT output the recovered
data while an LOS condition is being declared.
NOTE: In this mode, RPOS_(n) and RNEG_(n) is set to "0",
asynchronously.
Bit D2 - RxOFF (Receive Section - Shut OFF Se-
lect)
This Read/Write bit-field is used to shut-off the Re-
ceive Sections. The purpose is to conserve power
consumption when this device is the back-up device
in a Redundancy System.
Writing a "1" into this bit-field shuts off the Receive
Sections. Writing a "0" into this bit-field turns on the
Receive Sections.
Bit D1 - RxClk_(n)INV (Invert RxClk_(n))
This Read/Write bit-field is used to configure the
Channel(n) Receiver to output the recovered data on
either the rising edge or the falling edge of the
RxClk_(n) clock signal.
Writing a "0" to this bit-field configures the Receiver to
output the recovered data on the rising edge of the
RxClk_(n) output signal. Writing a "1" to this bit-field
configures the Receiver to output the recovered data
on the falling edge of the RxClk_(n) output signal.
Bit D0 - Reserved
This bit-field has no defined functionality
Command Register CR4-(n)
The bit-format and default values for Command Reg-
ister CR4 are listed below followed by the function of
each of these bit-fields.
COMMAND REGISTER CR4-(n)
D4
D3
Reserved STS-1/DS3_(n)
0
0
D2
D1
D0
E3_(n) LLB_(n) RLB_(n)
0
0
0
Bit D4 - Reserved
This bit-field has no defined functionality
Bit D3 - STS-1/(DS3_(n)) - Channel(n) - Mode Se-
lect
This Read/Write bit field is used to configure Chan-
nel(n) to operate in either the SONET STS-1 Mode or
the DS3 Mode.
Writing a "0" into this bit-field configures Channel(n)
to operate in the DS3 Mode. Writing a "1" into this bit-
field configures Channel(n) to operate in the SONET
STS-1 Mode.
NOTE: This bit-field is ignored if the E3_(n) bit-field (e.g.,
D2 within this Command Register) is set to "1".
Bit D2 - E3 Mode Select - Channel(n)
This Read/Write bit-field is used to configure Chan-
nel(n) to operate in the E3 Mode.
Writing a "0" into this bit-field configures Channel(n)
to operate in either the DS3 or SONET STS-1 Mode
as specified by the setting of the DS3 bit-field within
this Command Register. Writing a "1" into this bit-
field configures Channel(n) to operate in the E3
Mode.
Bit D1 - LLB_(n) (Local Loop-Back - Channel(n))
This Read/Write bit-field along with RLB_(n) is used
to configure Channel(n) to operate in any one of a va-
riety of Loop-Back modes.
Table 8 relates the contents of LLB_(n) and RLB_(n)
and the corresponding Loop-Back mode for Chan-
nel(n).
Bit D0 - RLB_(n) (Remote Loop-Back - Chan-
nel(n))
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