* Matthijs van Duin matthijsvanduin@gmail.com [170306 10:26]:
On 3 March 2017 at 17:19, Tony Lindgren tony@atomide.com 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.
OK good to hear there's no urgent need for fixes.
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.
OK
Regards,
Tony