Re: omap5-uevm sdcard supply woes

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On 3 March 2017 at 17:19, Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> Sounds like we should do that ASAP. Care to send a patch for that?

Never mind!

I'm more familiar with (e)MMC than with SD and incorrectly assumed the
card supply voltage is also its I/O voltage, but apparently an SD card
is required to generate its I/O supply voltage internally, and this is
switched to 1.8V by software command.

Now it all makes much more sense

main 3.3V ---[REGEN3]---> switched 3.3V to sdcard and LDO9
sdcard 3.3V ---[LDO9]---> host-side I/O supply
sdcard 3.3V ---[card-internal LDO]---> card-side I/O supply

Sorry for the false alarm.

There are still things that should be fixed to accurately reflect the
schematics, including the use of REGEN3 to be able to power-cycle the
card, but they are less urgent now and can wait until I've had time to
test them.

Matthijs
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