RAM calibration for iMX8mq custom board.

[trongthinh]

I have following the instruction in this document (https://community.nxp.com/docs/DOC-340179). I have already generated  "ddr_init.c" and "ddrphy_train.c" by using tool mscale_ddr_tool_v210_setup.exe.zip for one custom board. I have some questions need to be clarified:

1. I do calibration process for one board then I apply the result for all or I need to do for each board? Please advice!

2. If I do calibration process for more than one custom boards, How many custom board I need to do? 

3. If I do calibration process for more than one custom boards, there will be a lot of "ddr_init.c" and "ddrphy_train.c". How can I choose the correct one to integrate with u-boot?

[art]

The typical procedure of choosing the DDR calibration values for mass production units is as follows.

The calibration is performed on some reasonable (e.g. some tens of units) number of boards. Then, the average values of calibration parameters are calculated and applied for mass production.

Have a great day,
Artur

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[trongthinh]

how to calculate the average values of calibration parameters? Is there any document or example? 

Thank for your advice. 

[art · Accepted solution]

Sorry, I was wrong, what I've talked about is for i.MX6/i.MX7 series processors. For i.MX8M, due to the fact that the calibration procedure is self-training and performed at each board start-up, it is enough to use a single calibration procedure on a single hardware unit and use a single set of "ddr_init.c" and "ddrphy_train.c" to implement them to a target application (u-boot).

Best Regards,
Artur

[trongthinh]

It sounds great. Thank you for your answer.