PM7366-PI datasheet(68/286 Pages) PMC

68 / 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

channels. The TMAC also performs per-channel sorting of packets received in the TDR ready

queue to eliminate head-of-line blocking.

9.6.1

Data Structures

The TMAC communicates with the host using Transmit Descriptors (TD), Transmit Descriptor

References (TDR), the Transmit Data Reference Ready (TDRR) queue and the Transmit Data

Reference Free (TDRF) queue.

The TMAC reads packet data from data buffers in host memory. The TD, TDR, TDRR queue, and

TDRF queue are data structures which are used to transfer host memory data buffer information.

All four data structures are manipulated by both the TMAC and the host computer. The TD holds

the data buffer size, data buffer address, and other packet information. The TDR is a pointer

which is used to index into a table of TDs. The TDRR queue and TDRF queue allow the TMAC

and the host to pass TDRs back and forth. These data structures are described in more detail in

the following sections.

Transmit Descriptor

The Transmit Descriptors (TDs) pass buffer and packet information between the TMAC and the

host. Both the TMAC and the host read and write information in the TDs. TDs are stored in host

memory in a Transmit Descriptor Table. The Transmit Descriptor structure is shown in Figure 10.

Figure 10 – Transmit Descriptor

Reserved (5)

TCC[6:0]

Bytes In Buffer [15:0]

Transmit Buffer Size [15:0]

Data Buffer Start Address [31:0]

Host Next TD Pointer [13:0]

TMAC Next TD Pointer [13:0]

Bit 31

Bit 0

IOC

ABT

Reserved (16)

Res(2)

Table 11 – Transmit Descriptor Fields

Field

Description

Data Buffer Start Address

[31:0]

The Data Buffer Start Address[31:0] bits point to the data buffer

in host memory.

The Data Buffer Start Address field is valid in all TDs

Bytes In Buffer [15:0]

The Bytes In Buffer[15:0] field is used by the host to indicate the

total number of bytes to be transmitted in the current TD. Zero

length buffers are illegal.

PM7366-PI датащи(PDF) 68 Page - PMC-Sierra, Inc

PM7366-PI датащи(HTML) 68 Page - PMC-Sierra, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL