XRT73LC04A_08 Datasheet, PDF (55/64 Pages) Exar Corporation – 4 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT

REV. 1.0.2
XRT73LC04A
4 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT
FIGURE 36. THE XRT73LC04A EMPLOYING THE TRANSMIT DRIVE MONITOR FEATURES
TxPOS_(n)
TxNEG_(n)
TxLineClk_(n)
TTIP_(n)
TRing_(n)
TPData_(n)
TNData_(n)
TxClk_(n)
MTIP_(n)
R3 = 270Ω
MRing_(n)
Channel (n)
R4 = 270Ω
R1 = 31.6Ω
R2 = 31.6Ω 1:1
J1
BNC
Only One Channel Shown
When the Transmit Drive Monitor circuitry within a
given line is connected to the line, as illustrated in
Figure 36, then it monitors the line for transitions. As
long as the Transmit Drive Monitor circuitry detects
transitions on the line via the MTIP_(n) and
MRing_(n) pins, then it keeps the DMO (Drive Monitor
Output) signal "Low". If the Transmit Drive Monitor
circuit detects no transitions on the line for 128+32
TxClk periods, then the DMO (Drive Monitor Output)
signal toggles "High".
NOTE: The Transmit Drive Monitor circuit does not have to
be used to operate the Transmit Section of the
XRT73LC04A. This is purely a diagnostic feature.
4.6 THE TAOS (TRANSMIT ALL ONES) FEATURE
The XRT73LC04A can command any channel to
transmit an all “1’s" pattern onto the line by toggling a
single input pin or by setting a single bit-field within
one of the Command Registers to "1".
NOTE: When this feature is activated, the Transmit Section
of the configured channel overwrites the Terminal Equip-
ment data with this all “1’s" pattern.
a. Operating in the Hardware Mode
Configure Channel(n) to transmit an all “1’s" pattern
by toggling the TAOS_(n) input pin (pin 45, 46, 135 or
136) “High". Terminate the all “1’s" pattern by tog-
gling the TAOS_(n) input pin “Low".
b. Operating in the HOST Mode
Configure Channel(n) to transmit an all “1’s" pattern
by writing to Command Register CR1-(n) and setting
the TAOS_(n) bit-field (bit D3) to "1".
COMMAND REGISTER CR1-(n)
D4
D3
D2
D1
D0
TxOFF_(n) TAOS_(n) TxClkINV_(n) TxLEV_(n) Reserved
0
1
X
X
X
Terminate the all “1’s" pattern by writing to Command
Register CR1-(n) and setting the TAOS_(n) bit-field
(D3) to "0".
5.0 THE MICROPROCESSOR SERIAL INTER-
FACE
The on-chip Command Registers of XRT73LC04A
DS3/E3/STS-1 Line Interface Unit IC are used to con-
figure the XRT73LC04A into a wide-variety of modes.
This section discusses the following:
1. The description of the Command Registers.
2. A description on how to use the Microprocessor
Serial Interface.
5.1 DESCRIPTION OF THE COMMAND REGISTERS
(repeated as Table 7), lists the Command Registers,
their Addresses and their bit-formats.
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