Hi All,
I am starting some work that would be using an SD card (in MMC-SPI mode) and I was hoping to use a PIC or similar low memory chip.
The idea was to use Lewin Edward's DOSFS
The problem is that according to the SANDISK spec one can do sector writes of 512 bytes, but that an erase will operate on 32 sectors. This means that to update the directory or the FAT one needs to read out
16KB of data, do the erase, update the byte(s) in ram and write it all back again. This 16K block won't fit in a PIC.Have I misunderstood the requirements relating to SD / MMC for updating a sector?
--Rocky