PM73121ꢀAAL1gator II
Data Sheet
PMC-Sierra, Inc.
PMC-980620
,VVXHꢀꢁ
AAL1 SAR Processor
Field (Bits)
Description
FRAMES_PER_CELL
(13:8)
A 6-bit integer specifying the maximum number of frames required to have enough data
to construct a cell (round up of BYTE_PER_CELL/number of DS0s assigned) plus 1.
For example, for a T1 line in SDF-FR mode with five DS0s, initialize this field to 11. In
T1 SDF-MF, T1 SDF-FR, and E1_WITH_T1_SIG modes, the FRAMES_PER_CELL
is encoded as the number of 24-frame multiframes required in bit 13 and the number of
frames mod 24 in bits 12:8. In all other modes, including unstructured T1 mode, encode
this value as the maximum number of 256 bit increments required to create a cell. For
unstructured mode with full cells, set this value to 3.
NOTES: • For channels with a single DS0, encode the value 48 as one multiframe and
24 frames.
• When calculating the FRAMES_PER_CELL value, do not subtract the
bytes used by signaling nibbles from the value. For example, for an
SDF-MF, single DS0, full cell connection, use the value 47 + 1 = 48 and
not 46 + 1 = 47.
• For SDF-MF connections using partial cells, set FRAMES_PER_CELL to
(round up of BYTE_PER_CELL/number of DS0s assigned) plus 2. This
prevents scheduling more than one cell per frame.
T_CHAN_NO_SIG
(7)
Set to 1 to send cells with no signaling when in SDF-MF mode. This is the same as
using this queue in SDF-FR mode, which means the structure forms on frame
boundaries instead of multiframe boundaries.
T_CHAN_UNSTRUCT
(6)
Set to 1 only when sending cells with a single DS0 without a pointer in the SDF-FR
mode. To conform to the CES standard V 2.0 (refer to Appendix B, “References”, on
page 203) when using a single DS0 in SDF-FR mode, no pointer should be used.
BYTES_PER_CELL
(5:0)
A 6-bit integer specifying how many bytes per cell are required if no structure pointers
are used. For UDF_HS mode, this value must be 47. This number must be set so the cell
generation rate per queue is slower than once per frame. For unstructured lines, this
means between 33 and 47. For structured applications, the BYTES_PER_CELL number
must exceed the number of DS0 channels allocated to the queue. For example, a two
channel queue may have the number set from 3 to 47.
NOTE: For SDF-MF connections with more than 16 channels allocated, the BYTES_
PER_CELL number must exceed the number of DS0 channels allocated to the
queue by two. For example, a 17 channel SDF-MF queue may have the number
set from 19 to 47.
T_CELL_CNT Word Format
Field (Bits)
Description
T_CELL_CNT
(15:0)
A 16-bit count of the data cells transmitted. Rolls to 0 from FFFFh. Initialize to 0. After
initialization, do not write to this word.
ꢀꢂꢅ
PMC [ PMC-SIERRA, INC ]
