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AR# 19455

9.1i EDK - "ERROR:MDT - opb_v20 (d_opb) - more than 16 slave(s) assigned!"


When generating a processor design with 18 devices on the OPB bus, I receive the following error messages from the EDK design tools:

"opb_v20 (opb) - C:\system.mhs:150 - 1 master(s) : 226 slave(s)

ERROR:MDT - opb_v20 (opb) - C:\system.mhs:150 - more

than 16 slave(s) assigned!

ERROR:MDT - platgen failed with errors!

make: *** [implementation/ppc405_0_wrapper.ngc] Error 2"


This is not a limitation of the OPB bus, but rather an arbitrary limit to the number of slaves supported. This restriction can be removed as follows:

1. From the EDK install, copy the entire OPB bus peripheral to a local pcore directory inside of the EDK project directory or other pcore repository. The OPB bus core can be found in a path similar to C:\EDK\hw\XilinxProcessorIPLib\pcores\opb_v20_v1_10_b.

2. In the local OPB bus copy, open the OPB bus ".mpd" file in a text editor from the data directory of the core. The file path will be similar to C:\myproject\pcores\opb_v20_v1_10_b\data\opb_v20_v2_1_0.mpd.

3. Modify the attribute OPTION MAX_SLAVES = 16 to be a larger number.

4. Save the file.

5. Close and re-open XPS.

NOTE:MAX_SLAVES values other than 16 have not been extensively tested by Xilinx. This solution applies to the opb_v1.10.c Core.

Alternatively, you can solve this issue by having a second OPB bus in the system and placing the extra peripherals on this bus. Using a second OPB bus in this way requires the use of an OPB-2-OPB bridge.

AR# 19455
Date Created 09/03/2007
Last Updated 12/15/2012
Status Active
Type General Article