PM73121 Datasheet, PDF (175/223 Pages) PMC-Sierra, Inc – AAL1 Segmentation And Reassembly Processor

Data Sheet
PMC-980620
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PMC-Sierra, Inc.
PM73121 AAL1gator II
AAL1 SAR Processor
R_INCORRECT_SNP Word Format
Field (Bits)
R_INCORRECT_SNP
(15:0)
Description
16-bit rollover count of cells with SNP errors. This is the atmfCESHdrErrors
counter from the CES specification. Initialize to 0. Once initialized, do not
write to this word.
R_CELL_CNT Word Format
Field (Bits)
R_CELL_CNT
(15:0)
Description
16-bit rollover count of received cells. This is the atmfCESReassCells counter
from the CES specification. Initialize to 0. Once initialized, do not write to this
word.
R_ERROR_STKY Word Format
NOTE: Receive sticky bits should be used for statistics gathering purposes only as there is no
means of clearing them without the possibility of missing an occurrence. Initialize to
0.
Field (Bits)
TRANSFER
(15)
CELL_RECEIVED
(14)
Not used
(13:12)
ALLOC_TBL_BLANK
(11)
POINTER_SEARCH
(10)
FORCED_UNDERRUN
(9)
SN_CELL_DROP
(8)
POINTER_RECEIVED
(7)
PTR_PARITY_ERR
(6)
SRTS_RESUME
(5)
Description
This bit is read then written with the same value each time the AAL1gator II receives a
cell. This feature allows the processor to determine if the AAL1gator II was in the
middle of a read then write cycle when the processor cleared the other sticky bits. To
accomplish this each time the processor wants to clear sticky bits, it should complement
this bit. Then, if an additional read of this bit showed it to be the wrong value, then the
AAL1gator II has had its sticky word update interrupted.
A cell was received.
Write with a 0 to maintain future software compatibility.
A cell was dropped because of a blank allocation table or because R_CHAN_DISABLE
(refer to “R_MAX_BUF Word Format” on page 157) was asserted.
A cell was dropped because a valid pointer has not yet been found.
A cell was dropped because a forced underrun condition exists. A forced underrun
condition can be caused by overruns and pointer mismatches.
A cell was dropped in accordance with the “Fast SN Algorithm” (as specified in ITU-T
Recommendation I.363.1).
A valid pointer was received.
A cell was received with a pointer parity error.
An SRTS resume has occurred. A valid SRTS value was received and stored in the
SRTS FIFO.
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