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Altera_Forum's avatar
Altera_Forum
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14 years ago

Qsys to custom HW interface

My FPGA design, including a Nios II, resides mostly inside the Qsys environment. However, I have some custom hardware elements outside of Qsys. I need to pass data and control signals between the two environments, but not having much success.

I tried using an Avalon-MM Pipelined Bridge, exporting the master, but that didn't work. Now I am using a Tristate Conduit Bridge in line with a Tristate Conduit Pin Sharer and Generic Tristate Controller. It seems that the TCB wants to connect to pins rather than internal logic.

Can someone please recommend a good way to connect Qsys with on-chip logic outside of the Qsys environment?

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    What are the requirements of your interface? Timing, throughput, and format all impact the best choice. For simple devices, just use a PIO...

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    I am trying to connect Qsys to on-chip logic outside the Qsys environment and would like for the logic to appear to the Nios II SW as a wrtie-able location (such as RAM). In other words, when SW writes to this address it generates an external write signal along with the output data. I also need to read from a separate address.

    I use this method to connect to external SRAM with no problem, but it does not seem to work with on-chip logic.

    The problem with a PIO is that it does not generate a write signal. I suppose I could create one as on of the PIO bits, but that's a lot of extra SW that I would rather do without.
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    If you can do it with SRAM, the same should work with on chip component, too.

    You can expose the master signals or use those of a SRAM interface.

    Is your problem in exporting the interface out of Qsys block or did you implemented and connected everything but it doesn't work?

    The latter is definitely a problem in your component logic or timing related.