T8207 Datasheet, PDF (123/158 Pages) Agere Systems – ATM Interconnect

Advance Data Sheet
September 2001
CelXpres T8207
ATM Interconnect
14 Registers (continued)
Table 98. PPD Information 6 (PPDI6) (0210h)
Name
ppd_pnt2_sel[5:0]
ppd_pnt3_sel[5:0]
Reserved
Bit Pos.
5:0
11:6
Type Reset
Description
RW X PPD Pointer 2 Select.
The ppd_pnt2_sel[5:0] bit field selects which bit of the cell
header, the cell bus routing header, or the tandem routing
header is used as this offset bit.
RW X PPD Pointer 3 Select.
The ppd_pnt3_sel[5:0] bit field selects which bit of the cell
header, the cell bus routing header, or the tandem routing
header is used as this offset bit.
15:12 RO
PPD Pointer 2 and 3 Select.
The ppd pointer select bits are used to create an offset into the
PPD state memory. The PPD state memory is used to keep
track of AAL5 virtual channels for partial packet discard. Up to
8192 virtual channels may be supported with these select
fields. The ppd_pnt12_sel[5:0] bits select the most significant
bit of the PPD state memory offset, and the ppd_pnt0_sel[5:0]
bits select the least significant bit of the offset. A value of zero
to 31 selects bits in the cell header where zero is the CLP bit
and 31 is the most significant bit of the GFC/VPI field. A value
of 32 to 47 selects bits in the tandem routing header where 32
is the least significant bit and 47 is the most significant bit. A
value of 48 to 63 selects bits in the cell bus routing header
where 48 is the least significant bit and 63 is the most signifi-
cant bit. The value, “110000,” is a special case and may be
used to force the value of this bit to ‘0.’ If this bit is forced to
zero, the bit position in the resultant pointer is always ‘0’ and is
not extracted from the received cell.
0 Reserved.
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