Can anybody clarify a few issues as listed below with respect to the embedded software that is normally used on automobiles - say typically the engine management system or the climate control system:

1. Do they use a core that is different from the ones we normally use - say MCS51 for instance ?

2. What is the normal bus width for such applications - 4 / 8 / 16 bits ?

3. Are there any special conditions of reset / watchdog / safety etc. ( I would not like my car's EMS to freeze in the middle of nowhere because the watchdog kicked in )

4. And are they developed on a RTOS kernel always ?

In my line of profession I do quite a bit of hydraulic test rigs with the 8051 derivatives, and recently there was a customer who wanted to know the difference between the embedded software that we supply vis-a vis the ones on automobiles. Hence the query.

Thanks.

Raghunathan