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Visitor
Visitor
6,482 Views
Registered: ‎06-30-2012

memory test fails for ddr ram on spartan 3E

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hi, we are doing a project on spartan 3e 500k revision D board.we are having problem with our ddr sdram . we tried using opb_ddr, opb_mch v1.00b, opb_mch v1.00a and opencore IPs for ddr-sdram controllers without any success. the main problem is that memory is not  being refreshed. if we read data in the very next line of code after writing it its fine but later its garbage. how to solve the problem? plz do reply.

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Professor
Professor
8,381 Views
Registered: ‎08-14-2007

Re: memory test fails for ddr ram on spartan 3E

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Any hardware can be (or become) faulty.  If you want to know whether the board itself is

bad, and this is one of the standard development kits, there should be some pre-built

applications you can download and run to see if the board is working.  If the pre-built stuff

fails, then you probably have a bad board.

 

-- Gabor

-- Gabor

View solution in original post

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Professor
Professor
6,471 Views
Registered: ‎08-14-2007

Re: memory test fails for ddr ram on spartan 3E

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If I had to guess, I'd say the memory isn't working at all.  The fact that you can read it back

in the next line of code may mean that it is still in cache, or that the compiler has optimised

out the read.  If you change your C code to write / read using a volatile pointer like:

 

int * volatile mem_ptr;

int foo;

 

mem_ptr = (int *)DRAM_BASE;

*mem_ptr = 0x12345678;

foo = *mem_ptr;

 

Do you still get the correct data back?

 

-- Gabor

-- Gabor
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Visitor
Visitor
6,465 Views
Registered: ‎06-30-2012

Re: memory test fails for ddr ram on spartan 3E

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infact i was using the very same method that you have told but in vain. if i go for a virtex 2 pro ml300 board which i have never used previously will it be difficult for me. i have worked a lot with this spartan 3e created many peripherals and this and that, so how to resolve the issue , i use another board or i may get this ram working???

 

regards,

 

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Historian
Historian
6,457 Views
Registered: ‎02-25-2008

Re: memory test fails for ddr ram on spartan 3E

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@ibnejava wrote:

infact i was using the very same method that you have told but in vain. if i go for a virtex 2 pro ml300 board which i have never used previously will it be difficult for me. i have worked a lot with this spartan 3e created many peripherals and this and that, so how to resolve the issue , i use another board or i may get this ram working???

 

regards,

 


You could try debugging, you know.

----------------------------Yes, I do this for a living.
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Visitor
Visitor
6,454 Views
Registered: ‎06-30-2012

Re: memory test fails for ddr ram on spartan 3E

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Be a bit more specific. how to debug.?? regards, ibnejava
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Historian
Historian
6,449 Views
Registered: ‎02-25-2008

Re: memory test fails for ddr ram on spartan 3E

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@ibnejava wrote:
Be a bit more specific. how to debug.?? regards, ibnejava

How to debug?

How much electronics-engineering experience do you have?

 

----------------------------Yes, I do this for a living.
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Visitor
Visitor
6,445 Views
Registered: ‎06-30-2012

Re: memory test fails for ddr ram on spartan 3E

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sorry i mean what sort of debugging you meant. if you are talking of ordinary cutting-out-extra and check thing well we have done that for both H/W and S/W components but to no good. suggest any other solution. our seniors got the same board in their project and they left out the ddr sdram saying it was faulty and both of them were among the toppers of their time. one works for mentor graphics and the other is doing his phd. i just wanted to confirm if rams really can be faulty??

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Professor
Professor
8,382 Views
Registered: ‎08-14-2007

Re: memory test fails for ddr ram on spartan 3E

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Any hardware can be (or become) faulty.  If you want to know whether the board itself is

bad, and this is one of the standard development kits, there should be some pre-built

applications you can download and run to see if the board is working.  If the pre-built stuff

fails, then you probably have a bad board.

 

-- Gabor

-- Gabor

View solution in original post

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Visitor
Visitor
6,432 Views
Registered: ‎06-30-2012

Re: memory test fails for ddr ram on spartan 3E

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i think the board is faulty after all. :(

thanx for the help though

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