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Valued Contributor III
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Problem in using DDR

Hello everyone, 

 

I have a problem in using ddr on Cyclone III starter kit.When I have compiled the design,it failed at the fitter with this error notification. 

 

 

Error: can't place pin mem_dqs[1] to location T8. 

can't place VREF pin T6 (VREFGROUP_B3_N0) for pin mem_dqs[1] of type bidirectional with SSTL-2 Class I / o standard at location t8. 

 

can anyone help me please?
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2 Replies
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Valued Contributor III
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Re: Problem in using DDR

I face this problem before. You have to do some setting because there is too much bidir pins for 1 Vref.:) 

 

1st : 

Assigment-Device-Device and Pins option-Dual purpose pins(set all value to: use as regular I/O accept for DClock&nCEO. 

2nd : 

Assigment-Assigment Editor- Change all DQ,DQS and DM pins to (Output Enable Group). For the Value column, set any number same for those pins. 

eg: DQ[0]->Output Enable Group->123456(Value) 

3rd : 

Assigment-Pins(Change IO standard for all DDR related pins to SSTL-2 Class I.) 

 

You now are able to compile without any fail hopefully. I face this before and want to help you.:o 

 

Thank you: 

Shahril
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Valued Contributor III
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Re: Problem in using DDR

You are welcome. Just want to ask, is it currently you also work on DDR memory? It will be great if we can work together. I just want to store a series of data inside DDR SDRAM. Is it you already start to do the software part? 😮

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