Arria 10 DDR4 SODIMM calibration fails occasionally. How to remove this bug?

I'm assuming the 900 MHz you refer to is the external memory speed. Are you running your user logic at half or quarter rate (and meeting timing)?

Have you considered enabling the EMIF Debug Toolkit feature so you can see the results of calibration and figure out where the issue may be? See this online training for details:

https://www.intel.com/content/www/us/en/programmable/support/training/course/omem1124.html

#iwork4intel

Thank you for reply.

We running user logicat quarter rate (225 MHz)

Yes we know about EMIF Debug Toolkit .

At the moment when the bank is not calibrated, we see deviations along some lines.

But when the bank starts to calibrate after a series of Reset signals, then we see that everything is normal.

This situation occurs randomly.

At first we will try decrease memory frequency and use half rate at user logic

Best Regards

Igor

Make sure you run the DDR timing report in the Timing Analyzer to verify that you are meeting timing. This sounds like a potential timing issue.

#iwork4intel

Probably I should clarify. We now have more than one PCB we have 180 same boards. On some boards, bank B is calibrated stably at 900 MHz; on another number of PCBs, bank B is not calibrated continuously. sometimes yes, sometimes no. On the third, it does not calibrate at all. Today we decrease the frequency at the input oscillator so that the total became 600 MHz and those banks that were not calibrated are calibrated. It is very likely that in one batch of PCB there are differences in impedances on data lines and memory addresses. FPGA design is always the same.