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AR# 36741

MIG v3.5, Spartan-6 MCB - Traffic Generator Data Pattern cannot be modified


The Spartan-6 FPGA MIG tool includes a Debug Signal for a Memory Controller option which allows debug signals to be monitored using the ChipScope tool. 

This feature is very useful in hardware testing. 

The debug signals included are a part of the provided MIG Example Design (Traffic Generator).

In MIG 3.5, the debug port removed the ability to change the data pattern through the VIO ChipScope core. 

This was done to reduce logic and to ensure that the debug port was sized appropriately for all Spartan-6 devices. 

With the previous implementation, enabling the debug port with ChipScope cores caused the design to be too large for smaller Spartan-6 devices (specifically the XC6SLX9). 

If users wish to change the data pattern, minor rtl changes can be made to the example design. 

These changes are detailed in this answer record.


MIG 3.5 modified the assignment of DATA_PATTERN from DGEN_ALL to DGEN_ADDR. 

This limits the available data pattern to address as data. 

See UG416 > Traffic Generator Signal Descriptions for full details on the available data patterns. 

To enable the ability to use all data patterns in the debug port, modify the following:

1. Open the example_top.v module and modify the cx_vio_data_mode_value:

    // assign c3_vio_data_mode_value = 3'b010;
    assign c3_vio_data_mode_value = c3_vio_out[5:3] ;

This change allows the data mode to be changed using VIO.

2. Open the memcx_tb_top.v module and modify the assignment of the DATA_PATTERN parameter:


Note: These changes are required to run the SP60x reference design demos in hardware.

Linked Answer Records

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
35180 Spartan-6 - 12.4 Software Known Issues related to the Spartan-6 FPGA N/A N/A
AR# 36741
Date 09/02/2014
Status Active
Type General Article
  • Spartan-6 LX
  • Spartan-6 LXT
  • MIG
Boards & Kits
  • Spartan-6 FPGA SP601 Evaluation Kit
  • Spartan-6 FPGA SP605 Evaluation Kit
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