Lpc2000

--- In lpc2000@yahoogroups.com, "Paul Curtis" <plc@r...> wrote:
>
> Hi, 
> 
> > > Correct! If you want to log data continously only, why you want 
to 
> > > spent a lot of time in implementing a file system? Just write 
your 
> > > data byte4byte to your flash and wrap around if it is full.
> > 
> > Definitely concur on this point. Using a file system just to 
> > do some append-only logging like using a chainsaw to cut butter.
> 
> You can't write byte-by-byte to the LPC flash.  IIRC, an ECC byte 
cannot
> be changed without erasing the flash so you cannot over-program and
> already-programmed word.  Hence you must write in groups of four 
bytes
> aligned to a word boundary.  The other thing to say is that the IAP
> routines write a minimum of 256 bytes to a 256-byte-aligned page, so 
to
> synthesize word-wise writing you need a buffer of 256 bytes and a 
copy
> of the previous flash contents for the page.

Yes, that is very true for the LPC flash. Indeed, I cound not get the 
partial page programming to work reliably. Only full-page proigramming 
works reliably in my experience anyway.

Still, putting a full fs on the LPC flash would be overkill for 
sequential updates.

One thing to consider would be doing a very lightweight log structured 
fs.