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Altera_Forum's avatar
Altera_Forum
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15 years ago

SOPC error, SLAVE at two addresses

Let's see if I can paint the picture here:

I have a separate clock domain behind a Avalon Clock Crossing Bridge. In this clock domain I have a slave which can be accessed by our NIOS on the other side of the bridge, but this slave is also accessed by a master on the same side of the bridge as the slave. I get an error message that the slave is now at two addresses. Do I need a pipeline transfer bridge between the second master and slave? How do I fix this problem?

Pinscore

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    Could you please raise a SR. This issue has been going around for a long time now. It is a bug of SOPC Builder.

    The solution (fix) is to give the bridge and your slave the address 0x0.
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    Not really an option with the rest of the system and the way it is defined.

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    Hi Pinscore, Moov,

    Alas, for historical reasons, SOPC Builder enforces a "flat" address space. Usually, with some clever topology and bridges, you can make it flat.

    You can force SOPC Builder to generate even though there's an error, by holding the control key and clicking generate. (We don't promise the results will work, though!)

    Obviously, this address-space limitation is a little bit artificial. The switching fabric is just fine with it. But the Nios II BSP tools might not do well when confronted with the "mirage" address.

    We hope to relax this restriction in the future.
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    --- Quote Start ---

    You can force SOPC Builder to generate even though there's an error, by holding the control key and clicking generate.

    --- Quote End ---

    That's a great tip!

    I actually ran into the same addressing problem just a couple days ago. I changed the address of my problem bridge to zero to fix it, but I can foresee cases where that wouldn't work.

    --- Quote Start ---

    (We don't promise the results will work, though!)

    --- Quote End ---

    Do you promise my system will work when not forcing SOPC Builder to ignore the errors? :p