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

5.1.8.2. Write Descriptor Controller Avalon-MM Master Interface

The Avalon-MM Descriptor Controller Master interface is a 32-bit single-DWORD master with wait request support. The Write Descriptor Controller uses this interface to write status back to the PCI-Express domain and possibly MSI when MSI messages are enabled. This Avalon-MM master interface is only available for the internally instantiated Descriptor Controller.

By default MSI interrupts are enabled. You specify the Number of MSI messages requested on the MSI tab of the parameter editor. The MSI Capability Structure is defined in Section 6.8.1 MSI Capability Structure of the PCI Local Bus Specification.

Table 43.   Write Descriptor Controller Avalon-MM Master interface

Signal Name

Direction

Description

WrDCMAddress_o[63:0]

Output

Specifies the descriptor status table or MSI address.

WrDCMByteEnable_o[3:0]

Output

Specifies which data bytes are valid.

WrDCMReadDataValid_i

Input

When asserted, indicates that the read data is valid.

WrRdDCMReadData_i[31:0]

Output

Specifies the read data for the descriptor status table entry addressed.

WrDCMRead_o

Output

When asserted, indicates a read transaction.

WrDCMWaitRequest_i

Input

When asserted, indicates that the Avalon-MM slave device is not ready to respond.

WrDCMWriteData_o[31:0]

Output

Specifies the descriptor status table or MSI address.

WrDCMWrite_o

Output

When asserted, indicates a write transaction.