PM73121ꢀAAL1gator II
Data Sheet
PMC-Sierra, Inc.
PMC-980620
,VVXHꢀꢁ
AAL1 SAR Processor
NEW FEATURES
Changes in the AAL1gator II (PM73121) version from the WAC-021-C-X version are as fol-
lows:
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After power-up, setting the CMD_REG_ATTN register bit (refer to page 166) causes the
device revision register to be loaded with code 121Ah.
•
Supports the “Fast Algorithm” method for processing SNs, as specified in the ITU-T
Recommendation I.363.1.
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This method maintains bit integrity through any single corrupted cell, single misin-
serted cell, or up to six missing cells as determined by the value of the SN and SNP
field. However, bit integrity cannot be maintained if an underrun occurs.
If structured cells are used, adjustments for missing or errored pointer cells are consid-
ered. Pointer cells will be predicted to be in the cells that should contain pointers as
determined by the ITU-T Recommendation I.363.1.
The value of the inserted cells can be FFh, old data, one byte of conditioned data, or
pseudorandom data that uses the conditioned data and replaces the MSB with a pseu-
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dorandom pattern x + x + 1. The pseudorandom option is not available for UDF-HS
mode. The pattern used is selectable on a per-VC basis.
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The maximum number of cells, (MAX_INSERT) in the R_SN_CONFIG word (up to
six) inserted per queue is programmable on a per-queue basis (refer to
“R_SN_CONFIG Word Format” on page 160).
There is a bit, DISABLE_SN in the R_SN_CONFIG register (refer to
“R_SN_CONFIG Word Format” on page 160), to optionally disable SN processing
for a queue.
A bit has been added to disable the automatic dropping of the first cell received, as
would be normally required by ITU-T Recommendation I.363.1 (refer to
“NODROP_IN_START” on page 161).
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The UTOPIA interface can operate as an SPHY or MPHY device, in addition to its current
ATM mode.
When a queue underruns, old data, one byte of conditioned data, or pseudorandom data
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that uses the conditioned data and replaces the MSB with a pseudorandom pattern (x + x
+ 1) will be automatically inserted. The choice is selectable per DS0. Pseudorandom
options are not available for UDF-HS mode.
•
Added the following seven new counters per queue:
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number of dropped cells
number of lost cells
number of pointer reframes
number of underruns
ꢃ
PMC [ PMC-SIERRA, INC ]
