imx6dl - ddr3 issues.

theodebrouwere · ‎02-23-2017

Hi,

I have a custom design with a imx6dl, combined with 4 * 2Gbit DDR3 ram

Samsung K4B2G1646F-BCK0, running as DDR3-800.

I generated timings

* using the I.MX6DQSDL DDR3 Script Aid V0.10 document

* reading data sheets & calculating the register contents (attached)

I've been trying to obtain additional settings with the DDR_Tester application. (ddr_stress_tester_v2.60)

However, the tool always ends with the following issue.

Starting DQS gating calibration

*** snip ***
ERROR FOUND, we can't get suitable value !!!!
dram test fails for all values.

Error: failed during ddr calibration

It seems that the first part (Write level HW calibration) runs fine.

I've search the forum, and I noticed that there are others with similar problems.

I've tried several things (like increasing WALAT), but without any results.

I also tried several boards, all of them have the same problem.

Any idea what could be wrong? Is one of my settings wrong? Hardware failure?

Anything that I can try next?

Original Attachment has been moved to: ddr3.txt.zip

Original Attachment has been moved to: MX6DL_samsung_ddr3.inc.zip

theodebrouwere · ‎03-01-2017

Just for reference: we discovered that one of our NVcc pins was connected to ground instead of 3V3.

So, this is/was a hardware issue.

But, thanks for the reply. :smileyhappy:

Yuri · ‎02-27-2017

Hello,

You may look at sections 3.3.1 (Identifying Issue on Calibrations)

and 3.3.2 (Identifying Issue on Stress Test) of the following document.

Most often calibration errors concern with PCB design inaccuracy.

Please check Your PCB design using Chapter 3 (i.MX 6 Series Layout Recommendations) of the Hardware Development Guide

In particular, please use to Excel page named “MX6 DRAM Bus Length Check” in “HW Design Checking List for i.Mx6”, linked below.

Have a great day,

Yuri

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