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MX6Q Custom Board : DDR3 ODT Settings & Bypass LDO

Question asked by ottawa-imx6 on Feb 26, 2014
Latest reply on Apr 10, 2014 by Yixing Kong

Hello everyone,

I am trying to optimize power and thermal on a custom MX6D board since it is running a little bit too hot for me and am interested in hearing about other peoples results.

Currently I am running mainline 3.14.1 on a custom mx6D board with 2GB of MT41K256M16HA-125E.

 

This week, I tried two things in an effort to cool things down a little bit.

 

1. Modifying the ODT Settings  based on app note 4579.  http://cache.freescale.com/files/32bit/doc/app_note/AN4579.pdf.

This states that power savings of up to 40% can be seen by optimizing this value.

I have updated the following  (for P0 and P1) to see if any change was evident:

 

DATA 4, MX6_MMDC_P0_MPODTCTRL, 0x00022227

to

DATA 4, MX6_MMDC_P0_MPODTCTRL, 0x00000007

 

but I do not see any changes at all.

Are there other modifications required for this change to take effect? I was surprised that there was no difference since everything I have read stated that this would have an effect.

 

 

2. Next, I have also tried to switch to using my external PFuze regulator and disabled the internal LDOs by putting the system in LDO Bypass mode. Everything boots up fine using VCORE 1.1V, and VSOC 1.2V andI had to disable cpufreq to get this working since I have not implemented the voltage scaling yet.
In this case however, I do not see any thermal or power improvements either. I was expecting things to cool down a little by using an external pmic.

 

Does anyone have any experience or thoughts on these two things or any other methods of improving the thermal performance of a custom board using software methods?

 

Thanks!

 

Brent

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