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Altera_Forum's avatar
Altera_Forum
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12 years ago

Problem about the alternative boot method

I have used the method in AN485(alternative nios boot method) to build one boot loader(copier), but I have some problems.

1. if there is no interrupt in the boot copier, the exception section must be erased to FF before initialized. Otherwise, the interrupt in the application can't be triggered. But if there is one interrupt in the boot copier, the erasing process in not needed.

2. in the method proposed in the article, the application sections overwrite the boot sections. So there must be some bankruptcy with the application section writes to the section where the pc points to. However, we don't meet this problem using this method. How did you avoid that bankruptcy, and is there some risk of bankruptcy using this method?

Best Wish

Eric

1 Reply

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

    Hi Eric,

    1. As the boot copier is simple and single threaded, I believe it designed where interrupt support is not needed.

    2. Hmm based on my understanding, the boot copier code is reside under ROM area such as the memory within the EPCS controller. With that, it would not be corrupted. Or maybe you can point the particular page mentioned about this?

    Thanks

    Chin Liang