PM7375-SC datasheet(103/430 Pages) PMC

103 / 430 page

PM7375 LASAR-155

DATA SHEET

PMC-931127

ISSUE 6

LOCAL ATM SAR & PHYSICAL LAYER

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

9.14.11

Receive Management Queues

RMDRs pointing to free RMD are passed from the PCI Host to the RRM using the

Receive Management Descriptor Reference Free (RMDRF) Queue. In order to take

advantage of burst PCI transfers, the RRM reads up to six RMDs from the RMDRF

Queue and stores them locally. The RRM uses a free RMD to store OAM, Signaling

and Control cells to pass to the PCI Host using the Receive Management Descriptor

Reference Ready (RMDRR) Queue.

Both Queues reside in PCI Host memory and are defined using a common base

pointer residing in the PCID Receive Queue Base register and eight offset pointers,

four per queue. For each queue, two pointers are required to define the start and

the end of a queue while two pointers are required for the current write and read

locations within the queue. The read pointer always points to the last location read

while the write pointer always points to the next location to be written.

A full condition for the queues is defined as the read and the write pointers being

equal. An empty condition is defined as the read pointer being one less then the

write pointer. The last location in a queue is not considered as part of the queue

and thus is not a valid entry.

PM7375-SC Datasheet(PDF) 103 Page - PMC-Sierra, Inc