PM7366 datasheet(71/286 Pages) PMC

71 / 286 page

RELEASED

PM7366 FREEDM-8

DATA SHEET

PMC-1970930

ISSUE 4

FRAME ENGINE AND DATA LINK MANAGER

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

Figure 11 – Transmit Descriptor Table

TDTB[31:4] = Tx Descriptor Table Base register

TDR[13:0] = Transmit Descriptor Reference

TD_ADDR[31:0] = Transmit Descriptor Address

TDTB

Bit 0

Bit 31

TD_ADDR

TD1

TD2

TD 16384

Dword 0

Dword 1

Dword 2

Dword 3

TDTB[31:4]

TDR[13:0]

Bit 31

Bit 0

TD_ADDR[31:0]

Dword 0

0000

Dword 3

Transmit Queues

Pointers to the transmit descriptors (TDs) containing packet(s) ready for transmission are passed

from the host to the TMAC using the Transmit Descriptor Reference Ready (TDRR) queue, which

resides in host memory. Pointers to transmit descriptor structures whose buffers have been read

by the TMAC are passed from the TMAC to the host using the Transmit Descriptor Reference

Free (TDRF) queue, which also resides in host memory. The TMAC contains a Free Queue

cache which can store up to six TDRs. If caching is enabled, free TDRs are written into the TDRF

queue six at a time, to reduce the number of host memory accesses. The Free Queue cache is

PM7366 Datasheet(PDF) 71 Page - PMC-Sierra, Inc