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MFric2
Beginner
465 Views

SDR SDRAM Controller MAX II

Hey guys,

iam trying to Interface an SDR SDRAM from Micron with a MAX II CPLD.

 

Iam able to read between 10 - 400 Adresses but then i think because of timing issues the Read fails...

 

Because iam using an MAX II iam not able to get a PLL for the SDRAM Clock.... are there any reliable ways to Phase Shift the SDRAM Clock without a PLL ? Or does someone can give me tipps to constraint my Design with a Zero Phase shift ?

 

Currently iam driven the Controller and SDRAM with the same 100 Mhz clock from an external oscillator.

 

SDRAM : Micron MT48LC4M32B2B5-7 Max II : EPM1270

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3 Replies
NurAida_A_Intel
Employee
36 Views

Hi Sir,

 

You can try to constraint the output clock from the FPGA using generated clock constraint as explain in this link:

https://www.intel.com/content/www/us/en/programmable/support/support-resources/design-examples/desig...

 

Hope this is helpful.

 

Thanks.

 

Regards,

NAli1

a_x_h_75
New Contributor III
36 Views

Are you issuing refresh cycles regularly enough? The fact you can successfully read something suggests to me it might not be a timing issue...

 

Cheers,

Alex

MFric2
Beginner
36 Views

Hey,

 

it has turned out that my sdram controller wont take care if there is a read request at the same time with an automatic auto refresh command so they overlap... which obviously fails

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