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DDR4 controller DQS pins

User1580871742356367
357 Views

I wonder if the polarity of DQS signal can be inverted inside FPGA (not HPS), for example, bank 3F or 3H. 

The DQS_P and DQS_N connection are reversed at one DDR4 device side and there 4 DDR4 devices forming a 64 bit memory bank. 

Hope to hear from ASAP. Thank you.

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4 Replies
AdzimZM_Intel
Employee
347 Views

Hi Sir,


Thanks for posting your question in Intel Community.


Unfortunately, you cannot change the polarity of the DQS signal.


Regards,

Adzim


User1580871742356367
328 Views

Hi Adzim,

 

Appreciate quick response.

I know the DQS P/N pins can not be changed or swapped.

I meant inverting DQS in the VHDL or Verilog code, for example, somewhere in the MIG, like put a NOT gate.

ASAP, thank you.

AdzimZM_Intel
Employee
279 Views

Hi Sir,

 

I don't think you can do that due to timing related issue.

Besides, the signals are harden circuitry that you not able to change it.

 

Regards,

Adzim

sstrell
Honored Contributor III
304 Views

I'm presuming you're using a hard controller and PHY.  If so, no, you can't do that.  You wouldn't want to either due to extra delay.

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