XRT73L03A Datasheet, PDF (54/62 Pages) Exar Corporation – 3 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT

XRT73L03A
3 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT
REV. 2.0.4
FIGURE 37. THE XRT73L03A 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)
R4 = 270Ω
Channel (n)
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 37, 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". However, 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 XRT73L03A.
This is purely a diagnostic feature.
4.6 THE TAOS (TRANSMIT ALL ONES) FEATURE
The XRT73L03A can command any channel to trans-
mit an all “1’s" pattern onto the line by toggling a sin-
gle 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 “High". Terminate
the all “1’s" pattern by toggling 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) TxBIN_(n)
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 XRT73L03A
DS3/E3/STS-1 Line Interface Unit IC are used to con-
figure the XRT73L03A 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.
52