Why do some microSD cards work others don't?
I have several larger microSDHC cards (8gb-16gb) which can be read and written to with my 3.3v pro mini. I bought some 128mb cards that fail to initialize using Card info sketches from the sd and sdFat libraries.
I have reformatted the cards using:
The only answer I have been able to find is "some cards just don't work"
Are there any recommendations for getting the right cards?
For others wandering down this path I found some help on reddit:
https://www.reddit.com/r/arduino/comments/b3vpz3/why_do_some_microsd_cards_work_while_others_dont/
Do you have a feeling that one specific answer there was more likely to be the correct one?
I have heard that different cards draw different amounts of current. My hypothesis was that the non-working cards were drawing more current than your power supply could manage. However, that's purely a guess. I see that someone on Reddit mentioned the same idea.
SD cards are meant to work with 5V systems as far as I know.
Asking them to work at 3.3V is stretching.
I think it's the opposite. SD cards are 3.3 V. However, many (though not all) common Arduino SD modules contain level shifting hardware so that they can be used with a 5 V Arduino. If you try to use one of those with a 3.3 V Arduino, that could be problematic.