XRT75L04D Datasheet, PDF (33/98 Pages) Exar Corporation – FOUR CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER

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XRT75L04D
REV. 1.0.1 FOUR CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER
Case 1:
MTIP_1 connected to TTIP_1
MRING_1 connected to TRING_1
TxMON_1 (bit) = 0
As shown in the figure 18, connect MTIP_1 to TTIP_1 and MRING_1 to TRING_1 via the 270 Ω resistors.
When no transitions on the line are detected for 128 ± 32 TxClk_1 periods, the DMO_1 pin will toggle “High”.
The DMO_1 and the DMOIS_1 bits also will be set in the control register. When the transitions are detected,
the DMO_1 pin will toggle back to normal state. The DMO_1 bit also will be cleared. However, the DMOIS_1 bit
will remain set until read. If the DMOIE_1 bit has been set, an interrupt will be generated.
Case 2:
MTIP_1 connected to TTIP_1
MRING_1 connected to TRING_1
TxMON_1 (bit) = 1
This has the same effect as in Case 1. It is redundant to use the MTIP_1/MRING_1 pins in this case.
Case 3:
MTIP_1 not connected to TTIP_1
MRING_1 not connected to TRING_1
TxMON_1 (bit) = 1
When no transitions on the TTIP_1/TRING_1 are detected for 128 ± 32 TxClk_1 periods, the DMO_1 pin will
toggle “High”. The DMO_1 and the DMOIS_1 bits also will be set in the control register. When the transitions
are detected, the DMO_1 pin will toggle back to normal state. The DMO_1 bit also will be cleared. However, the
DMOIS_1 bit will remain set until read. If the DMOIE_1 bit has been set, an interrupt will be generated. Please
note that the MTIP_1/MRING_1 pins cannot be used to monitor any other adjacent channels.
Case 4:
MTIP_m not connected to TTIP_m +n where m = 0,1...3 and n = 0,1...3
MRING_m not connected to TRING_m +n where m = 0,1...3 and n = 0,1...3
TxMON_n (bit) = 0
In this case, with external connection, any of the MTIP/MRING can be connected to any of the adjacent
channel to be monitored.
Please note that if TxMON_n bit is set, then monitoring will be done for that channel n. By toggling the
TxMON_n bit from 0 to 1, the monitoring can be switched between self-monitoring to monitoring any adajcent
channels.
NOTE: The Drive Monitor Circuit is only for diagnostic purpose and does not have to be used to operate the transmitter.
4.5 Transmitter Section On/Off:
The transmitter section of each channel can either be turned on or off. To turn on the transmitter, set the input
pin TxON_n to “High” (in Hardware Mode) or write a “1” to the TxON_n control bits (in Host Mode) with
TxON_n pins tied “High”.
When the transmitter is turned off, TTIP_n and TRing_n are tri-stated.
NOTES:
1. This feature provides support for Redundancy.
2. If the XRT75L04D is configured in Host mode, to permit a system designed for redundancy to quickly shut-off the
defective line card and turn on the back-up line card, writing a “1” to the TxON_n control bits transfers the control
to TxON_n pins.
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