Released
Datasheet
PM73487 QRT
PMC-Sierra, Inc.
PMC-980618
Issue 3
622 Mbps ATM Traffic Management Device
2.4.2.1 UTOPIA Level 2 Polling
The UTOPIA interface offers three modes of polling, as per the UTOPIA Level 2 specification:
•
•
•
Standard single cell available polling
Multiplexed Status Polling (MSP) using four cell available signals
Direct status indication using four cell available signals
These polling modes allow the QRT to communicate with many different PHY devices. Figure 19
shows the QRT polling PHY devices in a receive UTOPIA operation.
QRT polls PHYs to determine if they have cells.
Serial In
PHY
Device
Serial In
PHY
Data
To Switch Fabric
Device
QRT
(PM73487)
Address
Cell Available
Serial In
PHY
Device
Figure 19. Receive UTOPIA Operation
Figure 20 shows the QRT polling PHY devices in a transmit UTOPIA operation.
QRT polls PHYs to determine if they can accept cells.
Serial Out
Serial Out
PHY
Device
Data
PHY
Device
From Switch Fabric
QRT
Address
(PM73487)
Cell Available
Serial Out
PHY
Device
Figure 20. Transmit UTOPIA Operation
20
PMC [ PMC-SIERRA, INC ]
