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DXu2
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6 years ago

DDR4 SODIMM 内存 修改位宽Fitter失败

客户目前板子上做的 DDR4(SODIMM 72bit) ,当初做管脚验证的工程都可以编译通过，并且已经制版。 由于成本问题，客户想更换DDR4 厂家 ，接口还是SODIMM。现在修改了DDR4 IP (SODIMM 64bit) ，但是软件无法Fitter通过，请问这个无法Fitter 的原因是什么？ 客户目前布局在 2k ，2l ,2m,2n 4个bank 里面，其中2l 是...
NurAida_A_Intel's avatar
NurAida_A_Intel
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6 years ago

Dear DXu2,

I am sorry for the delay in response due to current workload.

Proper design practice is to verify fitter placement first before proceed to board design.

  • If customer later decided to change EMIF design then I would expect customer to change their board design as well. As far as I'm aware of, there is no other option to this.

Normally it’s fine to reduce DQ width and by right it shouldn’t hit fitter error

  • 72 bits = 64 bits + 8 ECC bits.
    • Changing the design to 64 bits meaning customer just disable ECC option in EMIF IP so fitter should still work with x64 bit DQ
  • Also, make sure that the add/cmd pins located at the middle bank as this is the requirement when using multiple I/O banks.

Sorry I couldn’t be more helpful. This is the best I can do. Let me know if there is any help needed.

Regards,

Aida