RELEASED
PM73123 AAL1GATOR-8
DATASHEET
PMC-2000097
ISSUE 2
8 LINK CES/DBCES AAL1 SAR
Note: In SDF-FR mode, the CES specification states that if the queue contains
data for only one DS0, no pointer is used. If a queue is configured in this
manner, set R_CHAN_UNSTRUCT in the R_BUF_CFG receive queue table
memory register..
• The value of the payload data depends on the value of INSERT_DATA in the
R_SN_CONFIG receive queue table memory register.. The default is to load
the value of 0xFF. Other options are to use conditioned data as defined by
R_CONDQ_DATA, old data, or pseudorandom data. If old data is chosen, no
data will be written and the old data in the receive buffer will be used. The
receive buffer write pointer will be adjusted to the correct location. If the
pseudorandom data option is chosen, the data played out will be the value of
R_CONDQ_DATA with the MSB replaced by the current value of the
pseudorandom number generator x18 + x7 + 1.
Notes:
• All DS0s within the replaced cell will use the same algorithm. To
minimize the overhead of generating the inserted cells, use the old
data option whenever possible. The old data option still needs to do
internal processing on a byte-by-byte basis, but since it does not have
to write any data, it is about twice as fast as the other options.
• The “Fast SN Algorithm” will, under certain situations, allow bad cells
to pass through. When this occurs the cells are marked as potentially
bad. Any cells marked as potentially bad will not have pointer
verification done on them and any signaling data or SRTS information
they contain will not be written. However, if these cells should contain
pointers or signaling data, adjustments are made to the amount of
payload data written so bit integrity is maintained.
• The pseudorandom option is not available for UDF-HS mode.
The RALP will maintain bit integrity if there is no more than one consecutive
errored cell, or if there are up to six lost. If the receive buffer underruns and
BITI_UNDERRUN is set, then the amount of time that has passed since the last
cell is checked and if it appears that less than 6 cell times have passed then cells
will be inserted if no more than MAX_INSERT cells are detected as lost.
Otherwise the queue will resync and realign with the structure if one exists.
MAX_INSERT controls the maximum number of cells that will be inserted when
cells are lost. If more cells than MAX_INSERT are lost, then the queue will be
forced into an underrun condition unless the lost cells are a result of coming out
of underrun. The default value of MAX_INSERT, “000”, is equivalent to “111”
PMC-SIERRA, INC. PROPRIETARY AND CONFIDENTIAL
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PMC [ PMC-SIERRA, INC ]
