AnsweredAssumed Answered

mx28 DDR2 vs core speed

Question asked by Bogumil P on Mar 4, 2014
Latest reply on Jul 1, 2014 by Yixing Kong

Hi

I have a pilot series of custom boards with imx287, 64MB DDR2, power + boot _prep, non OS.

I tested configurations from Table14 in datasheet - recommended operating states.

These are first test results:

1) core 454MHz DDR2 205MHz - RAM R/W errors sometimes, on some units (max. config)

2) core 454MHz DDR2 160MHz - RAM R/W errors sometimes, on some units (this is not listed in datasheet as recommended state)

3) core 393MHz DDR2 160MHz - everything ok an all units, acceptable for our application.

Tested few voltages, including max. levels, don't really change results.

 

What I don't know is where is the problem - core speed, DDR2 speed or relationship between them?

I understand this could be poor layout of DDR2, cause we're using simple EDA PCB software.

I also know that DDR2 configuration might need some changes in software - a fine tuning of timings, but I don't want to do it now.

But if above is true, than test 2) and test 3) should work the same, right?

Core 454MHz without external RAM R/W (runs from internal RAM - boot_prep) run stable on all units, so it seems it's not an issue.

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