5812-DS01-R datasheet(10/84 Pages) BOARDCOM

10 / 84 page

BCM5812

Advance Data Sheet

3/11/03

B roa dcom Co rpo rat ion

Page 2

Programming Interface

Document

5812-DS01-405-R

host software can sense the MCR1_FULL and MCR2_FULL flags in the DMA Status CSR, bits 30 and 27 respectively.

These flags are zero when their respective MCR FIFO can accommodate at least one new MCR address.

Figure 2: BCM5812 Programming Overview

Each packet descriptor entry is 32 bytes long, and contains a pointer to a command context structure along with initial input

and output fragment chain entries. The chain entry structures are buffer descriptors used to support input and output scatter-

gather operations. Each provides the address and length, in bytes, of a buffer fragment, and a pointer to a next fragment

chain entry. The packet descriptor also supplies the total length of the input. Figure 4 on page 4 diagrams the format of a

packet descriptor.

The command context indicates the actual operation to be performed. The first 32-bit word is common to all command

context types, and indicates the operation to be performed and the total length of the command context structure itself, in

Table 1: MCR Header Word (Input)

Bits

Description

Suppress Interrupts

30:16

Reserved

15:0

Number of Packets

MCR

Host Memory

MCR1@

PCI Memory Space

DMA Control

DMA Status

MCR2@

DMA Error

CSR

Device ID

PCI Configuration Space

Vendor ID

Memory BAR0

PCI Bus DMA

Command Context

Data Buffers

5812-DS01-R 数据表(PDF) 10 Page - Broadcom Corporation.

5812-DS01-R 数据表(HTML) 10 Page - Broadcom Corporation.

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

数据表下载