Released
Datasheet
PM73487 QRT
PMC-Sierra, Inc.
PMC-980618
Issue 3
622 Mbps ATM Traffic Management Device
Figure 72 shows an example of connecting the QRT to the QSE using the Vitesse VSC7135 and
the VSC7214.
× 16
PLD
VSC7135
VSC7214
PLD
QRT
QSE
(PM73487)
(PM73488)
BP_ACK
Figure 72. Connecting the QRT to Gigabit Ethernet Transceivers
Another interconnection method is to put all the signals from two or three interfaces over a link,
including the SOC line.
NOTE: The BP_ACK_IN(3:0) signal does not always go to the same card as the data and SOC signals. For
example, the data signals might go to the first stage of the fabric and the BP_ACK_IN(3:0) signal
would go to the third stage of the fabric. For this reason, the BP_ACK_IN(3:0) signal often cannot
be combined with the data and SOC signals in a serialized interface. These signals can be combined
in a switch fabric that had the first and last stages of the fabric on the same card.
11.2 Connecting to Standard Serializer/Deserializer Chipsets
The QRT/QSE can be connected using standard serializer/deserializer chipsets such as those pro-
®
®
vided by Hewlett Packard and National Semiconductor .
The Hewlett Packard serializer/deserializer chipsets, HDMP-1012/1014, HDMP-1022/1024, and
HDMP-1032/1034 (preliminary), are ECL, 5V and 3.3V devices, respectively, that can run at 66
Mhz.
These devices are ideally suited for gang four applications, where the 16 data lines and a single
copy of the SOC can be turned into a single differential pair.
In certain 3-stage fabrics, the BPACK and data can share the serializer: 16 data lines, a single
copy of the SOC and the four BPACK signals can be turned into a single differential pair when
the devices run at 62.5 Mhz.
More infomation about these devices can be found at:
http://www.hp.com/HP-COMP/fiber/sg/gen_chip.html
227
PMC [ PMC-SIERRA, INC ]
