PM73487 QRT
PMC-Sierra, Inc.
PMC-980618
Issue 3
622 Mbps ATMTraffic Management Device
Released
Datasheet
91
6.4.1
Switch Fabric Cell Formats
Table 21 on page 91 and Table 22 on page 92 define the switch fabric interface cell formats for
data cells and idle cells, respectively.
Table 21. QRT-QSE Interface Cell Format.
*
When the phase aligners are turned on, Tsesu and Tseho are no longer defined. However, the maximum input and output
skew and jitter on these signals with respect to the SE_SOC_IN is constrained to specification listed in this table.
** This is assuming the SYSCLK is operating at 100 Mhz. To operate the device fabric interface at other frequencies, refer to
“Relationships Among Various Clock Domains” on page 229
.
Nibble
Symbol
Definition
Comment
0
Pres(1:0), MC, SP
Pres = 10
b
: Valid cell present.
Pres = 01
b
: Idle cell.
Pres = 00
b
: Invalid cell.
Pres = 11
b
: Invalid cell.
MC = 1
b
:
Multicast cell.
SP:
Spare bit. Programmed via the
RX_CH_CONFIG register (refer
to
section 9.3.1.1
“RX_CH_CONFIG” starting on
page 184
).
1
SP(1:0), Prior-
ity(1:0)
SP(1:0) Spare bits.
Priority = 11
b
High-priority cell.
10
b
Medium-priority cell.
01
b
Low-priority cell.
00
b
Undefined. Cell discarded by
QSE.
The QRT should be configured never to gen-
erate priority 00
b
cells, since they are dis-
carded by the QSE.
2
TAG_0_6
Routing tag 0.
MCG_3
The QSE interprets all four nib-
bles as the MCG.
3
TAG_1_7
Routing tag 1.
MCG_2
4
TAG_2
Routing tag 2.
MCG_1
5
TAG_3
Routing tag 3.
MCG_0
6
TAG_4
Routing tag 4.
7
TAG_5
Routing tag 5.
8
TAG_0_6
Routing tag 6.
9
TAG_1_7
Routing tag 7.
10
OUTCHAN_3
Intepreted as OUTCHAN(15:12) by the QRT.
Not used by the QSE.
Symbol
Parameter
Signals
Min
Max
Unit