Microcontrollers used in OEM systems

[Mike Palmer]

> From:          Matt Sale <mds at mot.delcoelect.com>
> Subject:       Re: Microcontrollers used in OEM systems
> 
> 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

<*snip*>

> 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.
> 

Your point is well taken. Mind you, the P4 ECM PCB looks like it's 
got plenty of room for more stuff...it's not dense at all :)


> 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.
> 

So the beancounter legend is real!...I thought that was just an old 
wives tale: "If you can save $0.02, make it so!"

But seriously, the HC11 as it comes from Motorola can be had with an 
8-channel A/D converter and SCI built in. Why then does the P4 seem 
to require a separate UART device and separate A/D converters?  If 
cost minimalization was paramount, surely a few cheesy signal 
conditioners (a few op amps, caps and resistors) would have been 
cheaper than spreading block functionality (i.e. SCI, A/D etc) around 
the board in separate chunks of silicon and the effort required to 
route the PCB and place the parts...

...well, of course it wasn't, otherwise the (what I imagine were) 
extensive cost analysis studies undertaken be GM/Delco as to the unit 
cost of, say, a P4 would have fleshed this out.

This is quite fascinating and I thank you for taking the time.

 


- Mike

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1994 Probe GT 
Leather/PMoonroof/5-speed
"You'll laugh, you'll cry, you'll hurl..."

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