3 ms·
I would have guessed a signal to the local microprocessor to stop any writes as well. Oh well. So would the solution be for the host, or some SD adapter, to pr
by zaroth 9y ago
I would have guessed a signal to the local microprocessor to stop any writes as well. Oh well.
So would the solution be for the host, or some SD adapter, to provide a super-cap to ensure smooth shutdown of the SD unit as a whole?
- joezydeco 9y agoA supercap is indeed one way go to, but it's useless without a decent brownout detection circuit that doesn't freak out every time you lose an AC halfwave (happens more than you think).
- mschuster91 9y agoHmm. A supercap combined with a diode on 5V and a line to a GPIO from Vcc to provide enough time for the OS to shut down... like this (RPi GPIO) <-----------(resistor to 3v3)-| (RPi microUSB in) <-------------(diode <-)------+---- Vcc | Supercap (RPi GND) ----------------------------------- GND When the supercap is huge enough (or, for what its worth, use a powerbank with passthrough capability!), this should work - when the GPIO goes low, the system can initiate a safe shutdown, and especially it can signal a "shutdown" signal to the microSD.