[Arm-netbook] [EOMA68] RS232 on SoCs

joem joem at martindale-electric.co.uk
Sun Sep 8 11:57:33 BST 2013


> This entire thread sounds wrong.

 joe: it's not the A20 that's the problem, it's the AXP209 Power
Management Integrated Circuit.

 when the AXP209 Power Management Integrated Circuit is fed 3.3V into
its pins whilst it is powered off, it can get damaged.

 absolutely nothing to do with the CPU whatsoever.

--
OK I know how sort out such issues.
Which pins of the AXP209 are prone to this effect?
And define power off - i.e. which pin(s) (or is it entire board) is not receiving power?

I have to make SoM2 power supply again because of a pad size error.
This time I make it as a module with QFN like pads on square postage
stamp size PCB module which can be changed out until all engineering
issues are gone.



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