On 2023-06-13, Wols Lists wrote: > On 13/06/2023 03:01, John Blinka wrote: >> Good to know it all works, but if you're sticking a new card in an old >> reader, they may not be compatible. >> >> >> Don’t know what constitutes new/old, but these are <1 year old >> cards. Satisfied with empiric evidence that it all works. Have >> written mp3 files to this card and played them via Arduino/attached >> mp3 board. Sufficient for my purposes. Amazed that it all works! >> (Pushing beyond my comfort level with card reader/Arduino/mp3 >> board/wiring all this stuff together.) > > Basically, just a little bit of history ... > > When these cards came out, they were true SD. With a max capacity of > 4GB (4GB cards are actually rare as hens teeth ...) > > As 2GB became cheap and common, the technology transitioned to SDHC, > so your 4GB card is almost certainly SDHC, and will not work in a true > SD reader (like my 2009-era satnav). > > That had a limit of - iirc - 32GB, and as that became common the > technology transitioned to SDXC. This is where my knowledge becomes > rather hazy... > > But anyways, everywhere the card is newer than the reader, you have > the possibility of problems. It rarely happens, but I've been bitten > twice trying to upgrade the chips in cameras ... > > Cheers, > Wol
Curiously, I've just recently bought a bigger capacity card (32GB I think?), µSDHC, with an "SD adapter", and I learned that the (multi-slot) USB dongle I've been using does not support µSDHC (only µSD, apparently?)... but does support SDHC! -- Nuno Silva
