Missing writes on Custom board

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originally posted by shmueld@May 16 2006, 05:10 PM

i have an interesting problem. i have designed a nios system that i have implemented onto a custom boad. i have written a simple frimware program to check parts of the system. when i execute the firmware using the debug download of the ide i get all the expected writes. however when i execute the firmware using the "run" download a lot of the writes are missed. i thought this may be related to some sort of configuration of the ide. however when i downloaded my code to the epcs and ran from there on a reset i got the same results !?

i found this bug both when writing to my dual port ram (via a custom component) and also my logic interface (via a custom component)!

does anyone has any suggestion ?

<div align='right'><{post_snapback}> (index.php?act=findpost&pid=15408)

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Try to use a NIOS without caches - if it then works you should check your hardware access commands (always use IO commands to access hardware and not C pointers).

Try to use a NIOS without caches - if it then works you should check your hardware access commands (always use IO commands to access hardware and not C pointers).

<div align='right'><{post_snapback}> (index.php?act=findpost&pid=15424)</div>

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Dear stonie,

Thanks for your reply. I am not a software guy, so could you please explain to me what you mean by : "always use IO commands to access hardware and not C pointers" and why this should make a difference when running the code on my custom hardware directly compared to debug mode (which doesn&#39;t work properly)?

Are you using -O2 or -O3 in the run configuration? there may be some optimizations done by the compiler that removes some "unuseful" writes to memory.... did you declared your data as "volatile"?

Paolo

Another Interesting result:-

When I was carrying out single writes to my cusotmized NIOS logic Interface component, after every write I found that reads of every single address in the range of the interface was being done. With further investigation I found that these reads were even being done during the initialization of the pointers - (yes we are using pointers - I have requested from the software enginner to look into changing this and use "IO commands to access hardware " - although we are not yet sure what these are !) !

Does Anyone have any further suggestions ?

Note I have also requested from the Software Engineer to try to bypass the cache - it is all done through the softeware right ?

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originally posted by shmueld@May 16 2006, 08:10 AM

i have an interesting problem. i have designed a nios system that i have implemented onto a custom boad. i have written a simple frimware program to check parts of the system. when i execute the firmware using the debug download of the ide i get all the expected writes. however when i execute the firmware using the "run" download a lot of the writes are missed. i thought this may be related to some sort of configuration of the ide. however when i downloaded my code to the epcs and ran from there on a reset i got the same results !?

i found this bug both when writing to my dual port ram (via a custom component) and also my logic interface (via a custom component)!

does anyone has any suggestion ?

<div align='right'><{post_snapback}> (index.php?act=findpost&pid=15408)

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Read through the Nios II Software User&#39;s Guide. All of your answers/options are clearly stated there.

- slacker