Lpc2000

Jaya, 

> The AT91SAM7A3 very different to LPC I am afraid:
> 
> 1/ The AT91SAM7A3 has memory protection while LPC has none.

That isn't the issue under discussion.

> 2/ Flash programming is protected in AT91SAM7A3 manual while 
> it is not in LPC:

> I have not bothered checking up on your other references ... 
> and I ask that you do your homework first before making ambit
> claims.  I have done mine.

The protection offered by the SAM7S isn't safe as you suggest--the flash
programming registers are still available and can still be accessed, you
just need to get lucky and hit on an 8-bit key.  Given truly random
writes to this register, your probability of hitting the key is 1 in
256.

What *is* safe is, for instance, the MAC7100.  So safe, in fact, that
when the evaluation system was delivered to us it was fully locked down.
Unless you know the password programmed into the device, you cannot even
gain access to the flash programming registers.  At all.  Not only that,
the flash is protected so it is execute only, and you can't even READ it
if you download a program into RAM or if you're running the provided
monitor from flash.  That is secure.  However, my challenge was to find
such a system on a non-automotive ARM7 part.

--
Paul Curtis, Rowley Associates Ltd  http://www.rowley.co.uk
CrossWorks for MSP430, ARM, AVR and now MAXQ processors

> 
> Regards,
> 
> Jaya
> 
> >--- In lpc2000@yahoogroups.com, "Paul Curtis" <plc@...> wrote:
> > > The LPC2000 is no different to the SAM7 to the
> > > ADuC70x0 to the STR7 and so on.  None of these ARM 
> processors protect
> > > their flash registers from inadvertent access.  Same for 
> many other
> > > architectures with integrated flash--like the MSP430, 
> which I am very
> > > familiar with.
> > >
> > > Again, you are misunderstanding my question, deliberately or
> > > accidentally.  This is, I think, the central issue in 
> many of these
> > > discussions.
> > >
> > > --
> > > Paul Curtis, Rowley Associates Ltd  http://www.rowley.co.uk
> > > CrossWorks for MSP430, ARM, AVR and now MAXQ processors
> > >
> 
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