AXI Multichannel DMA Intel® FPGA IP for PCI Express* User Guide

ID 817911
Date 7/22/2024
Public
Document Table of Contents

4.5.8. User Event MSI (user_msi)

Interface clock : axi_lite_clk

Table 31.  User Event MSI Interface
Signal Name Direction Description
user_msi_req Input

MSI request signal. Assertion causes MemWrite TLP to be generated to Host based on the MSI Capability register values and other MSI input ports.

You can deassert MSI request any time after Acknowledge (user_msi_ack) has been asserted.

user_msi_ack Output

Acknowledge for MSI request.

Asserted for 1 clock cycle.

User logic can deassert the MSI request as soon as this signal is asserted.

user_msi_num[4:0] Input

MSI number that indicates the offset between the base message data and the MSI to send.

When multiple message mode is enabled, this signal sets the lower five bits of the MSI Data register.

user_msi_num[4:0] is not an option in the IP Parameter Editor.

The user application provides the MSI vector information when multiple messages are enabled.

For more information, refer to the Message Data Register for MSI in the PCIe base specification.

user_msi_func_num Input

Specifies the function number requesting an MSI transmission

user_msi_status[1:0] Output

Indicates the execution status of requested MSI. Valid when user_msi_ack is asserted.

  • 00: MSI message sent
  • 01: Pending bit is set and no message sent (MSI is masked)
  • 10: Error (MSI is not enabled or not allocated)
  • 11: Reserved