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

Matthijs van Duin matthijsvanduin at gmail.com
Thu Aug 17 16:56:26 CEST 2017


On 17 August 2017 at 16:49, Matthijs van Duin <matthijsvanduin at gmail.com> wrote:
> On 17 August 2017 at 15:38, Michael Mrozek <EvilDragon at openpandora.org> wrote:
>> * The timings are DIFFERENT when running with 400MHz (DDR3-800) and
>> often not in the datasheets.
>
> The datasheet of the RAM does specify the timings to be used for
> DDR3-800, and we are using them. These timings are also the same as
> for the single-rank ram.

Ignore me, I wasn't awake yet. I was confusing the pyra with the
beaglebone I think :-/

I think you can mostly get away with using DDR3-1066 parameters at 400
MHz, although it would unnecessarily slow. A few parameters need to be
adjusted however, like the max time a row is allowed to be open
(tRAS_max) and the refresh interval.


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