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Altera_Forum's avatar
Altera_Forum
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20 years ago

Problems compiling VHDL

Hello,

I'm using the NIOS II Development Kit on a Stratix II board equipped with an EP2S60 FPGA.

I need to implement VHDL blocks for image processing. My block needs to read pixels written in memory (about max. 512*512 pixels). I wrote a for-loop in Quartus II 5.0, in a VHDL file, but it doesn't compile. One error occured which is :

"Loop must terminate before or at 10 000 iterations".

But 512*512 pixels = 262 144 iterations !

I also tried to create a for-loop from 0 to 9999 and it works. So I thought I could duplicate this for-loop, but it doesn't compile too.

Has anyone had the same problem, or does anyone know how to make a 262144 iterations for-loop ?

For the moment, the only solution I got is to make a 128 pixels memory acces in one iteration, but I want to know if a VHDL for-loop is limited to 10 000 iterations.

Finally, I also tried to work with While-loops or Illimited-loops (with an exit condition), but the problem still remains : 10 000 iterations maximum.

If you know what to do, feel free to answer. If my problem is not clear exposed, feel free to ask questions.

Thanks for your reading,

Lord_Readbeard

2 Replies

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

    --- Quote Start ---

    originally posted by lord_redbeard@Apr 14 2006, 09:49 AM

    hello,

    i'm using the nios ii development kit on a stratix ii board equipped with an ep2s60 fpga.

    i need to implement vhdl blocks for image processing. my block needs to read pixels written in memory (about max. 512*512 pixels). i wrote a for-loop in quartus ii 5.0, in a vhdl file, but it doesn't compile. one error occured which is :

    "loop must terminate before or at 10 000 iterations".

    but 512*512 pixels = 262 144 iterations !

    i also tried to create a for-loop from 0 to 9999 and it works. so i thought i could duplicate this for-loop, but it doesn't compile too.

    has anyone had the same problem, or does anyone know how to make a 262144 iterations for-loop ?

    for the moment, the only solution i got is to make a 128 pixels memory acces in one iteration, but i want to know if a vhdl for-loop is limited to 10 000 iterations.

    finally, i also tried to work with while-loops or illimited-loops (with an exit condition), but the problem still remains : 10 000 iterations maximum.

    if you know what to do, feel free to answer. if my problem is not clear exposed, feel free to ask questions.

    thanks for your reading,

    lord_readbeard

    <div align='right'><{post_snapback}> (index.php?act=findpost&pid=14377)

    --- quote end ---

    --- Quote End ---

    The design is rather interesting for me.

    Obviously it&#39;s a large design for single HDL hardware, whether or not VHDL either Verilog will support this logic level compilation is a question you might get answer for this by referring HDL library.

    But I have a feeling Quartus II might not to be able to build such a big logic as well as this amount of registers (I think you don&#39;t have access to on chip memory from HDL) in one design.

    For design goal&#39;s sake, I will suggest to use DSP builder or system level design methodology. Buffering data will help.

    Good luck, or if you have any update please post.

    For your reference: Stratix II EP2s60 has total registers : 52,506
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    19 years ago

    --- Quote Start ---

    originally posted by lord_redbeard@Apr 14 2006, 03:49 PM

    my block needs to read pixels written in memory (about max. 512*512 pixels).

    <div align='right'><{post_snapback}> (index.php?act=findpost&pid=14377)

    --- quote end ---

    --- Quote End ---

    What kind of memory are you using? And how fast do you want to read the data? If you have enough time, you could just split up the access into smaller intervals instead of getting everything at once.