Design consideration help - Memory tester

Just testing the memory with your CPU's data master (what you're doing with your proposed test) is not good enough. The data master cannot read from the memory as quickly as the CPU's instruction master. A DMA will help you to truly "exercise" your memory's limits.

Take a look at what the Memory Test software example is doing. It already provides something along the lines of what you're trying to do...you may want to modify it to suit your needs, rather than starting from scratch.

Cheers,

- slacker

Excellent point about the DMA. Yes, the memory interface should be tested fully as well.

the other half of the testing should be to fully test each individual bit in memory, which obviously isn't possible if I bootload into the SDRAM. So does the multi-program approach where the memory tester is loaded into on-chip memory make sense?

Regards,

Kevin

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originally posted by kwolfe@Aug 8 2006, 08:39 AM

excellent point about the dma. yes, the memory interface should be tested fully as well.

the other half of the testing should be to fully test each individual bit in memory, which obviously isn't possible if i bootload into the sdram. so does the multi-program approach where the memory tester is loaded into on-chip memory make sense?

regards,

kevin

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Certainly. You&#39;d probably want to design a small piece code to run in on-chip RAM, that would fully exercise every bit in the memory.

Cheers,

- slacker

I really appreciate your help slacker. Thanks.

Hopefully I can pick your (or anyone elses) brain for one last issue. I&#39;ve loaded the mem test program onto my development board but adjusted it so that I&#39;m running out of the ext_ram (SRAM) and am trying to exercise the test routine on the SDRAM.

I&#39;m running into an issue where I get data corruption (the program &#39;crashes&#39;) if I run the test on addresses starting at 0x0100.0000 (which is SDRAM_BASE). However, I have no issues running the test at 0x0100.01c8 (VMA + LMA as reported in the objdump) and beyond.

Am I understanding it correctly that my SDRAM addresses are simply adjusted during the compile? Therefore, when I run the test at SDRAM_BASE, I&#39;m in fact really adjusting some other memory in the system space? If so, is there any way to dynamically hard code in what the SDRAM addresses will be? Or am I just way off and have a seperate issue at hand.

Thanks again,

Keivn

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originally posted by kwolfe@Aug 8 2006, 11:54 AM

i really appreciate your help slacker. thanks.

hopefully i can pick your (or anyone elses) brain for one last issue. i&#39;ve loaded the mem test program onto my development board but adjusted it so that i&#39;m running out of the ext_ram (sram) and am trying to exercise the test routine on the sdram.

i&#39;m running into an issue where i get data corruption (the program &#39;crashes&#39;) if i run the test on addresses starting at 0x0100.0000 (which is sdram_base). however, i have no issues running the test at 0x0100.01c8 (vma + lma as reported in the objdump) and beyond.

am i understanding it correctly that my sdram addresses are simply adjusted during the compile? therefore, when i run the test at sdram_base, i&#39;m in fact really adjusting some other memory in the system space? if so, is there any way to dynamically hard code in what the sdram addresses will be? or am i just way off and have a seperate issue at hand.

thanks again,

keivn

<div align='right'><{post_snapback}> (index.php?act=findpost&pid=17450)

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You&#39;re probably overwriting the code located at your Exception Address. Change this to something other than SDRAM (in SOPC Builder) and recompile.

Regarding your addressing question, it&#39;s absolute, but the switch fabric only makes the connections (master<=>slave) where necessary. SDRAM_BASE will always be SDRAM_BASE to those masters (CPU-IM, CPU-DM, DMA) that are connected to it.

- slacker

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originally posted by slacker@Aug 8 2006, 04:08 PM

you&#39;re probably overwriting the code located at your exception address. change this to something other than sdram (in sopc builder) and recompile.

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You nailed it. *smacks forhead*

Thanks again,

Kevin