PM5364 pmc-sierra, PM5364 Datasheet - Page 271

• Manufacturer Part Number: PM5364
• Description: Tupp 2488 Assp Telecom Standard
• Manufacturer: pmc-sierra

14.9
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2011334, Issue 7
High Order Receive Path Alarm
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All signals on the High Order Receive Alarm port are referenced to the HRALMCLK signal.
HRALMCLK is a nominal 20.736 MHz 33% high duty cycle clock. It is generated by gapping
an internal 25.92 MHz clock. This means every 2 out of 10 clock edges are skipped to trigger
exactly 2,592-clock pulses between each 125 µs interval. Note that all signals on this alarm port
are updated on the falling edges of HRALMCLK.
The HRALMFP signal provides synchronization between the alarm port and the transport
frame. It asserts high for 1 HPOHCLK clock cycle for every 125 µs. HRALMFP is used to
identify the first of 2,592-clock pulses of HRALMCLK.
Figure 88 shows the functional timing of HRALM for one complete 125 µs interval. HRALM is
time-multiplexed among the 48 STS-1/STM-0 paths. Each HRALM path is asserted or negated
for 24 HRALMCLK consecutive cycles and the HRALM value cannot be changed during this
duration. In each frame, HRALM reports all 48 paths alarm indications 2 times (two
opportunities). The two opportunities are mostly identical, but they could be different when
HRALM transitions in a frame depending on the frame timing. During the first 48
HRALMCLK and the last 240 HRALMCLK, the HRALM signal should be ignored.
Figure 88 High Order Receive Path Alarm Timing
The TUPP-2488 serially outputs the path alarm for all 48 paths through the High Order
Receive Path Alarm port. The HRALM signal is set high for each of the 48 high order
SONET/SDH paths when any of the following defects is active: LOP-P, AIS-P, RDI-P,
ERDI-P, LOPC-P, PAISC-P, UNEQ-P, PSLU, PLM, and PDI-P. Each defect can be
independently enabled or disabled for each path.
The High Order Receive Path Alarm port is comprised of the following signals:
HRALMCLK.
HRALMFP.
HRALM.
TUPP™ 2488 ASSP Telecom Standard Product Data Sheet
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