A device I had been testing for over two months suddenly started giving FR_DISK_ERR (I'm using Elm Chan's FAT-FS) [Link]. When I tried debugging, the command (CMD0) which must be clocked in to set the SD card into SPI mode (as described in the SD card spec sheet - SDcard.org [link]) return 0xFF and not 0x01, i.e. it failed.
My question is:
*If CMD0 fails does that mean the SD card controller is not working?
*Will it still work in SDIO mode even if CMD0 fails? (I couldn't test it as my uC does not support SDIO)
*Can an OS (Linux, Windows, Mac) format this SD card to make it working again? If so how does it do it?
Chan's FAT-FS has no method to solve if we have an FR_DISK_ERR, so I need to find a way to solve this remotely.