[Letux-kernel] 2GB vs. 4GB Pyra RAM tests

Tony Lindgren tony at atomide.com
Tue Aug 15 05:51:25 CEST 2017


* Matthijs van Duin <matthijsvanduin at gmail.com> [170814 02:31]:
> On 14 August 2017 at 06:39, Tony Lindgren <tony at atomide.com> wrote:
> > 1. Configure smps6 to 1.39V instead of 1.35V
> >
> > So what does this mean? Not enough power from palmas or too
> > low voltage for the 4GB DDR3 chip? Any ideas?
> 
> One thought that crossed my mind is that the 60Ω termination value
> configured in the ram might be inappropriate with two ranks. This
> value is configured in bits 24-26 of sdram_config:
> 0 = no termination
> 2 = 120Ω
> 1 = 60Ω
> 
> I think it would be worth testing 120Ω termination or even no
> termination at all (this should work if the drive strength on the omap
> side matches the traces to ram, and would reduce power consumption).

So far it seems that just changing your original timings
to have 0 for termination work with increased voltage
possibly the same way as the igepv5 settings.

With termination at 2 I don't think I got u-boot to load at
all.

Regards,

Tony


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