Released
PMC-Sierra, Inc.
PM9311/2/3/5 ETT1™ CHIP SET
Data Sheet
PMC-2000164
ISSUE 3
ENHANCED TT1™ SWITCH FABRIC
3.4.2.40 Output Backpressure/Unbackpressure Threshold
Symbol: EOPBPTHR
Address Offset: 000A0h
Default Value: 00001C46h
Access:
Read/Write
These thresholds are for Multicast queues only.
Bits
Description
31:15 Reserved
Output Unbackpressure Threshold. This specifies when the output port processor
de-asserts backpressure. When the Output Scheduler grants to an output queue, the output
port processor checks if the number of cells in that queue is equal to the threshold value. If the
two values are equal, then an unbackpressure signal is sent to the central scheduler. If the EPP
is in OC-48c mode, then this value should be changed to 1Fh.
14:8
7
Reserved
Output Backpressure Threshold. This specifies when the output port processor asserts
backpressure. When a cell from crossbar enters an output queue, the output port processor
checks if the number of cells already in that queue is equal to the threshold value. If the two
values are equal, then a backpressure signal is sent to the central scheduler.
6:0
3.4.2.41 Egress OC-48/OC-192c Mode Map
Symbol: EEMM
Address Offset: 000A4h
Default Value: 00000000h
Access:
Read/Write
Chooses OC-48c/OC-192c Mode.
Bits
Description
Port Mode select. Bits 0:31correspond to individual ports. If the bit is set to 1, the port is
OC-48; if set to 0, the port is OC-192c.
31:0
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
189
PMC [ PMC-SIERRA, INC ]
