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Altera_Forum's avatar
Altera_Forum
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16 years ago

Booting two Nios 2 processors on same FPGA

Hello ,

My design has 2 NIOS 2 processors.

I want to load a boot image into each of the processors.

I want to load it using the boot copier by means of EPCS method.

I have tried this method with one processor and it works just fine with the help of advanced boot copier method.

By modifying this advanced boot copier example even though I do manage to copy the individual boot images of the 2 NIOS processors I can jump to the entry point of only one processor.

How to make the processor work ?

Is there any work around ?

Also i have heard about some signals like ' cpu_reset_request' and 'cpu_reset_taken' that can be made availabe from the advanced feature tab of NIOS 2 processor component selection.

Can these signals be used in this scenario where there are 2 Nios 2 processors on the same FPGA ?

Best regards,

Rohit

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    A couple of ideas:

    1 - Let one processor boot first holding the other processor in reset via the cpu_reset_request signal.

    2 - Consider using a small custom peripheral connected to each CPU with a unique ID. Your bootloader can read this unique ID to determine any processor specific boot procedures that need to be performed (like which address in the EPCS device to grab the code from).

    3 - You don't have to have both CPUs boot from the EPCS Controller directly. You could have one processor use the EPCS controller as it's reset address. The second processor could simply have a piece of onchip memory that it boots from. You might have the second processor sit there and wait for a signal from the first processor; at which point it would begin it's bootloading process of copying needed data from the EPCS device.

    Just some ideas...

    Jake
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Hi Jake ,Thanks for your suggestions. I will try out those within a few days . Best Regards,Rohit