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Altera Arria V Avalon-ST User Manual

Page 185

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The following table shows the layout of the descriptor fields following the descriptor header.

Table 16-8: Chaining DMA Descriptor Format Map

Bits[31:22]

Bits[21:16]

Bits[15:0]

Reserved

Control Fields (refer to Table 18–9) DMA Length

Endpoint Address

RC Address Upper DWORD

RC Address Lower DWORD

The following table shows the layout of the control fields of the chaining DMA descriptor.

Table 16-9: Chaining DMA Descriptor Format Map (Control Fields)

Bits[21:18]

Bit[17]

Bit[16]

Reserved

EPLAST_ENA

MSI

Each descriptor provides the hardware information on one DMA transfer. The following table describes

each descriptor field.

Table 16-10: Chaining DMA Descriptor Fields

Descriptor Field

Endpoint

Access

RC Access

Description

Endpoint

Address

R

R/W

A 32-bit field that specifies the base address of the

memory transfer on the Endpoint site.

RC Address
Upper DWORD

R

R/W

Specifies the upper base address of the memory

transfer on the RC site.

RC Address
Lower DWORD

R

R/W

Specifies the lower base address of the memory

transfer on the RC site.

DMA Length

R

R/W

Specifies the number of DMA DWORDs to transfer.

2014.12.15

Chaining DMA Descriptor Tables

16-15

Testbench and Design Example

Altera Corporation

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