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Message
From: John Sheahan<jrsheahan@o...>
Date: Tue Oct 26 11:51:30 CEST 2004
Subject: [oc] Problems accessing SDRAM with mem_ctrl
Surely a little bit of debugging information could be in order here.
For eample - what do the the SDRAM transactions on the pins look like?
Has the SDRAM been initialized (wait+precharge + couple refresh + mode
write ?
etc....
john
Alexander Wirtz wrote:
> Sorry for being a pain in the a.., but could anyone *please* help me
> with this? I really need to get the memory going!
>
> Thanks again,
> Alex
>
> Alexander Wirtz wrote:
>
>> Hi folks,
>>
>> I'm trying to access two 256Mb MT48LC16M16A2 Chips with the Memory
>> Controller, which I have hooked up with the RS232 System Controller
>> for testing purposes. Accessing the configuration registers works
>> just fine, no problems there. The chips are using CS0 and I've set
>> the CSC0 to 0x91 to set the memory size to 256 Mb, bus width to 16
>> bit, type SDRAM and enable this chip select. I've left everything
>> else just as I've found it. The registers now look like this:
>>
>> 60000000 : 00000000 00024A9A 000007FF 00000000
>> 60000010 : 00000091 FFFFFFFF 00000000 00000000
>>
>> So the SDRAM is initialized with some random noise - ok. Accessing
>> the chips gives me
>>
>> 00000000 : 00024A9A 00024A9A 00024A9A 00024A9A
>>
>> Hmm... everything's the same... writing to it seems to work (writing
>> 0xFF to address 0x0). Reading again
>>
>> 00000000 : 000000FF 000000FF 000000FF 000000FF
>>
>> Hmpf... so now I'm stuck here. I've been following the manual to the
>> letter (I hope :)), wiring the memory controller to the wishbone and
>> the SDRAM. As I can access the configuration registers, the wishbone
>> doesn't seem to be the problem. The output to the chips is buffered,
>> I've checked the wiring of the pins at least twice... and I'm out of
>> my depth.
>>
>> I'd really appreciate some hints or help here...
>>
>> Thanks in advance,
>> Alexander
>>
>> P.S. If someone needs a bit of code or anything else, I'd be more
>> than happy to provide it in private email.
>> _______________________________________________
>> http://www.opencores.org/mailman/listinfo/cores
>>
> _______________________________________________
> http://www.opencores.org/mailman/listinfo/cores
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