Let the preprocessor decide wether this piece of code is compiled
at all. Previous behaviour was to compile it unconditionally and
rely on the optimizer to remove it after that. Trusting the
optimizer is fine, but only if the code is warning-free in all cases.
This is all the commands to read from and write to SPI,
initializing the card, read in blocks and so on. This should
make Petit FatFs actually usable.
So far read-only and no M-codes to let end users play with
this stuff.
The demonstration code was changed to list the SD card's
top level directory over and over again.
Some modifications to avoid file name conflicts with other parts and
make it compile. As the glue code to the hardware (spi.c/.h) is
still missing, there are a few warnings, of course.
Changes to this library are tracked in pff.c.
Markus Hitter