[En-Nut-Discussion] UROM file system and RAM vs Flash allocation on AT91SAM

[Ulrich Prinz]

>
> So given the page:
> 0101-1010 1100-0011 1111-1111 1111-1111
> if you were to want to store 0001-0000 in byte 2 (0 indexed, of
> course) you could either write:
> 0101-1010 1100-0011 0001-0000 1111-1111
> or
> 1111-1111 1111-1111 0001-0000 1111-1111
> into that page without having erasure and it would probably work on
> many devices, but
> wouldn't be guaranteed?
>
On normal FLASH from AMD, Spansion and others, this does not work as you 
get a programm error bit set. The internal comparision fails and the 
programming is aborted. I don't know about modern dataflashes.

Best regards, Ulrich