Microcontrollers used in OEM systems

[Matt Sale]

> 
> 
> But it's funny that they'd go to what must be the huge expenditure 
> of custom packaging alot of custom-designed silicon instead of just 
> designing with what is commercially available (i.e. use an 'HC11E9 in 
> expanded mode and an 'HC24 to get the lost ports back etc). Every 
> chip under the 'hood' of a GM ECM seems to be custom...why not use 
> automotive-grade commercially available stuff? Wouldn't that cost 
> quite a bit less overall?
>  

Actually, when you spread the cost over several million parts
per year, it makes quite a bit of sense to spend the extra time
effort and money to create a custom derivative.  Remember too
that much of the chip design remains the same from derivative
to derivative (CPU, timers, SPI/SCI), but some people need 
PWM's, some don't.  Some need EEPROM, some don't.  Some need
A/D, some don't.  Each of these functions carries a price tag
on it.  A chip with unused blocks wastes silicon, and silicon
isn't free (despite what Mickeysoft thinks).  Adding parts to
boards to get functions that can be up-integrated wastes board
space and incurs extra costs for the additional parts.

You'd be amazed at how many 68300 family and TI parts we've
commissioned, I know I am.  Every electronic box in a car has
a micro, or so it seems.  The radio, ABS, air-bag, remote
keyless entry, instrument cluster, HVAC control, and ECM 
each gets its own micro, at least in the high-end cars.  Each
box has a unique set of requirements, and a price/value.

If it weren't for DE, you might not even have a 68332 for 
the EFI332 project.

Printer companies, camera companies, even toy companies 
commission custom micros.  Just look at Motorola's web
site sometime, down in the AMCU and CSIC areas.  Or look
at how many variants of PICs exist from Microchip Technology.
Every customer wants a part that exactly fits his application,
no more, no less.

-- 
Matthew D. Sale,  IC Development Engineer, Delco Electronics Corp.
msale at iquest.net   http://www.iquest.net/~msale
'69 Mustang 351W 5-spd (13.464 at 103MPH using cave-man technology).

All responses are my own and should not be mistaken
for those of Delco Electronics or General Motors.