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Altera_Forum's avatar
Altera_Forum
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16 years ago

Decoding Cyclone III SOF header

I'm using remote update to go from factory image to application image. After remote update loads the application configuration, I now need to copy the application NIOS II firmware to RAM for execution. I am trying to mimic the bootloader by loading the application from EPCS to upper RAM, skipping the configuration, and copy the application to lower RAM.

When I read the EPCS, I see the 56 that the bootload is syncing to, but after skipping 4 bytes, I see nothing reasonable for the length of the configuration (yes, after bit reversiving the bytes). Here is the beginning of the SOPC .flash file. The 56 is on line 3 - but which bytes are the length? It should be the CFCFCFDF following the bootloader code, but this cannot be the configuration size. What did I miss - where is the configuration size:

S01100004E6577426F6172642E666C617368A0

S32500000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFA

S3250000002056EFEFEFEFCFCFCFDF5F0FDF5F0F9F9F3FBFBF1F5FDF9F9FDF7F5FFFBF9FBF3FF3

S325000000409F3F1F3F1F3F1F5F5F959BFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF08

I do know from the end of the .flash file that it's 0x55B41. Bit reversed that's 0xA0dA82. I don't see this in the header above.

Thanks for anyone's help!

Bill

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Thank you. I've reviewed those files and source code - it's why I asked about syncing on the 0x56 byte - I see the bootloader do this. But in my header in the first post, I don't see the length 4 bytes past the 0x56 - what did I miss?

    Thanks,

    Bill
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    It seems you are using the algorithm to find the length for Cyclone II. You should be looking at boot_loader_epcs_bits_sii_siii_ciii.S to know how to find the length for Cyclone III.

    For Cyclone III, one bit from each of bytes 33-39 and bytes 48-72 form a 32 bit length value for the total number of bits. Using your data, I determined the length to be 0xABB41 bytes. Maybe I picked out the wrong bits when I did this, as this still does not quite match the value you posted.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Thanks so much Kevin! This was the problem - I saw boot_loader_epcs_bits_cyclone.s and then missed the file name with the ciii in the name. Yes, I see how they extract the bits - much more difficult!

    Bill