Hey stephane

Is it a MUST to have a onchip ADC?

There are more ADC chips on the market than can be counted in a week, most of them with some kind of serial interfcae. That way around, you could use the LPC 900 chips, and choose whatever ADC suits your demands.

BTW - I would have guesed that siemens (infenion) was on your list - BOSCH (have) used a lot of 80535 µC's for ignition systems.

kind regards

Per Guldmann