still correcting & being corrected (was adaptive ECU)

[isham-research.freeserve.co.uk at pop.pol.net.uk]

> But, on the subject of non-volatile memory, I will
> assert that a memory circuit that you can wipe by
> simply removing power _IS_ VOLATILE!  The ECU is
> simply obtaining some of its power sources straight
> from the battery rather than through key switches,
> relays, etc.

All memory circuits are ultimately volatile - it's just a question
of the size of the bomb.  My point is that the MAC14 is non-volatile
in normal use, whereas MAC01/02/05/07/11/12 lose their stored codes
whenever the ignition is switched off.

> I've worked on a tremendous amount of electronic gear
> with backup batteries (often lithium) used for memory,
> product configuration, clock/calendars, ad nauseam.
> It is my understanding that true "non-volatile" memory
> means you have memory that won't change state when all
> power is removed.  There was one group of products
> that had a very stringent method to change said
> battery...if you got it wrong, you needed to send the
> product back to the factory for reprogramming.

The radio originally envisaged for the ur-quattro had seventy memories
that were guaranteed to retain programmed frequencies for ten years
using EEPROMS.

Unfortunately Audi decided that Blaupunkt had a better reputation in
overseas markets than Philips - just as Daimler-Benz has had to drop
the superb Becker range in many export markets because the brand is
virtually unknown.

--
 Phil Payne
 UK Audi quattro Owners Club
 Phone +44 7785 302803   Fax: +44 7785 309674