Arria® 10 or Cyclone® 10 GX Avalon® Memory-Mapped (Avalon-MM) DMA Interface for PCI Express* Solutions User Guide

ID 683425
Date 9/10/2024
Public
Document Table of Contents

5.1.7. Avalon-ST Descriptor Control Interface when Instantiated Separately

After fetching multiple descriptor entries from the Descriptor Table in the PCIe* system memory, the Descriptor Controller uses its Avalon® -ST Descriptor source interface to transfer 160-bit Descriptors to the Read or Write DMA Data Movers.

Table 36.   Avalon® -ST Descriptor Sink InterfaceThis interface sends instructions from Descriptor Controller to Read DMA Engine.

Signal Name

Direction

Description

RdAstRxData_i[159:0]

Input

Specifies the descriptors for the Read DMA module. Refer to DMA Descriptor Format table below for bit definitions.

RdAstRxValid_i

Input

When asserted, indicates that the data is valid.

RdAstRxReady_o

Output

When asserted, indicates that the Read DMA read module is ready to receive a new descriptor.

The ready latency is 1 cycle. Consequently, interface can accept data 1 cycle after ready is asserted.
Table 37.   Avalon® -ST Descriptor Sink Interface This interface sends instructions from Descriptor Controller to Write DMA Engine.

Signal Name

Direction

Description

WrAstRxData_i[159:0]

Input

Specifies the descriptors for the Write DMA module. Refer to DMA Descriptor Format table below for bit definitions.

WrAstRxValid_i

Input

When asserted, indicates that the data is valid.

WrAstRxReady_o

Output

When asserted, indicates that the Write DMA module engine is ready to receive a new descriptor. The ready latency for this signal is 1 cycle. Consequently, interface can accept data 1 cycle after ready is asserted.