Lpc2000

At 07:59 AM 3/7/04 +0000, you wrote:
> > I am starting to evaluate LPC2100 family and I've got a question
> > about interrupt vector 0x14, which is checked by the bootloader. Is
> > there a way to tell the linker, that it must be an inverted
>checksum
> > of remaining vectors? Or Philips ISP utility automaticaly sets it
>to
> > a proper value?

The Philips ISP program does indeed do this.

> > Isn't there also a shortcomming in a bootloader logic? Suppose for
> > example that the flash is unprogrammed (all vectors are
> > 0xffffffff's). So their checksum is 0, which for the bootloader is
>a
> > valid program! Or may be the checksum, which is used is not simple
> > EORing of all 8 vectors?

Since the boot logic only checks the exception vectors, I don't see that it 
matters.  It doesn't guarantee that the program is complete anyway.  It's 
also more checking than at least some ISP chips do (they simply execute 
whatever is there).


" '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