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

ID 683425
Date 6/03/2021
Document Table of Contents

Test Interface SignalsThe test_in bus provides run-time control and monitoring of the internal state of the IP core.






The bits of the test_in bus have the following definitions. Set this bus to 0x00000188.

  • [0]: Simulation mode. This signal can be set to 1 to accelerate initialization by reducing the value of many initialization counters.
  • [1]: Reserved. Must be set to 1’b0.
  • [2]: Descramble mode disable. This signal must be set to 1 during initialization in order to disable data scrambling. You can use this bit in simulation for Gen1 and Gen2 Endpoints and Root Ports to observe descrambled data on the link. Descrambled data cannot be used in open systems because the link partner typically scrambles the data.
  • [4:3]: Reserved. Must be set to 2’b01.
  • [5]: Compliance test mode. Set this bit to 1'b0. Setting this bit to 1'b1 prevents the LTSSM from entering compliance mode. Toggling this bit controls the entry and exit from the compliance state, enabling the transmission of Gen1, Gen2 and Gen3 compliance patterns.
  • [6]: Forces entry to compliance mode when a timeout is reached in the state and not all lanes have detected their exit condition.
  • [7]: Disable low power state negotiation. Intel recommends setting this bit.
  • [8]: Set this bit to 1'b1.
  • [31:9]: Reserved. Set to all 0s.


Indicates the current speed of the PCIe link. The following encodings are defined:

  • 2b’00: Undefined
  • 2b’01: Gen1
  • 2b’10: Gen2
  • 2b’11: Gen3