GTS AXI Streaming Intel® FPGA IP for PCI Express* User Guide

ID 813754
Date 11/04/2024
Public
Document Table of Contents

6.5.2. Configuration Extension Bus Response Interface

The application returns read data for requests received from the Configuration Extension Bus Request interface using Configuration Extension Bus Response interface. The GTS AXI Streaming IP is always ready to accept responses from the application. The application should provide response data with a valid qualifier.
Table 66.  Configuration Extension Bus Response Interfacen = 0 or 1, p0 = port 0, and p1 = port 1
Note: Port 1 is only available in D-Series FPGAs
EP = Endpoint, RP = Root Port, BP = TLP Bypass
Signal Name Direction Port Mode Clock Domain Description
p<n>_ss_app_st_cebresp_tvalid Input EP p<n>_axi_lite_clk

The application should assert this signal for one clock to indicate that valid data is driven on the p<n>_app_ss_st_cebresp_tdata bus.

p<n>_app_ss_st_cebresp_tdata[31:0] Input EP p<n>_axi_lite_clk

Response data from the application for read request issued using st_cebreq interface.

The following figure shows the timing diagram for back-to-back write and read commands; the first command sends write for all four bytes of register located at address 4. The second command sends a write for byte 3 and byte 2 of same register. The third command sends a read for same register. Upon receiving the read command on the st_cebreq interface, the application returns data on st_cebresp interface. The data returned is 0x05080201 as the upper two bytes are modified by the second write.
Figure 53. Timing Diagram for Configuration Extension Bus Response Interface