Lpc2000

At 02:25 PM 3/14/04 +0100, you wrote:
>Perhaps because if you write wrong things to the booter or abort writing, it
>could be that you must throw away the chip, because you can't flash it
>anymore...

They may also wish to update the flash (and its programming algorithm) and 
that's harder to do if users have been programming the algorithm themselves 
while a callable version can remain the same despite underlying changes.  I 
belive ST changed their interface on the ST10 for just that reason.  They 
had to update the flash and rather than expose a new set of timing 
requirements they hid the details in a "callable" routine.

There are also support costs to consider.  I have heard that one of the 
largest support costs for flash based micros that expose the algorithm is 
supporting customers implementing the programming software.

Finally, the method that Philips uses to store the programming SW leaves 
open the possibility of tweaking the programming parameters on a batch by 
batch or even chip by chip basis.  If they were to do that it would 
obviously be much more difficult to expose to the public.

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III