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Altera_Forum's avatar
Altera_Forum
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20 years ago

Problem with Peripheral Communication

Hello,

i'm using the SOPC-Builder version 4.2 Build 178.

I have created a Custom Peripheral with the new component wizard. This peripheral has a avalon tristate slave interface with data, adresses , read_n write_n and wait_request_n. The communication to my peripheral look very well. But sometimes i have two accesses to the peripheral, but in my "C"-Code i make only one read access. I use a 16bit peripheral, a 16bit interface and a 16bit-pointer to read.

Do anyone know this effect?

What can I do against this?

Because if I read the peripheral address the data will be deleted. So I read out a ZERO.

Thanks for answers

Jens.

1 Reply

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

    Judging by your description this peripheral is a FIFO?

    When you used component editor to import the logic did you specify a native or memory type? Unless the peripheral is actually memory then you would probably want native addressing.

    Assuming you go with native addressing, are you bypassing the Nios II data cache? (if you have a data cache that is)

    Have you tried to capture the signals either using an external LA or SignalTap II? (looking at the signals may shed more light on what you are seeing).