DDR3L calibration frequency

[martinneumaier]

Hi, we use i.MX6D (industrial) under Linux with dynamic CPU frequency from 400MHz-1200MHz. Our uboot makes DDR3L calibration with 800MHz during startup.

During DRAM test under Linux (memtester) we sometimes get errors on individual CPUs. Do you think this is because the frequency during calibration is just 800MHz? We tried to increase the frequency to 1200MHz but then the Linux boot sometimes crashes.  

[igorpadykov]

Hi Martin

please try nxp latest ddr tester for calibration (not from uboot)

https://community.freescale.com/docs/DOC-105652 

In general memtester stresses board better than ddr test so it may produce errors,

while ddr test not. In such case one can pay attention to power supplies stability guidelines

described in i.MX6 System Development User’s Guide

http://cache.freescale.com/files/32bit/doc/user_guide/IMX6DQ6SDLHDG.pdf

If issues happen only with 1200MHz seems this is supplies/board noise issue.

Best regards
igor
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[martinneumaier]

At the moment we use one 4Amp single supply for CORE and SOC instead of a PMIC, maybe this is not enough?

In your personal opinion, do you think the i.MX6D (industrial 800MHz) is stable at 1200MHz ?

[igorpadykov]

for 1.2GHz marking should be like: MCIMX6Q5EYM12AC, industrial
(marking MCIMX6D7CVT08AC) works only up to 800MHz,

its stable opearation at 1200MHz is not guaranteed.

~igor