Microcontrollers used in OEM systems

[Mike Palmer]

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

> > 
> Depends on the hc11 derivative.  Each derivative has its own
> memory map (A8, F1, K4, E9, ...).  "Reserved" generally means
> unimplemented.  If you try to read one,
> you might get $FF, or you might get an address back, depending
> on the addressing mode & what was last driven on the internal
> data bus.

Yes...I'm aware of the differences between each of the commercially 
available variants like those you mention. But when Delco built the 
P4 for example, the core of the HC11 they apparently used was clearly 
different than that which the public can buy. For example, the 
registers aren't at $1xxx anymore and even resetting the COP timer 
seems wacky when compared to how the 'normal' HC11 does it.

In my Nippon Denso Probe GT PCM, there are references to registers 
that are either labeled in every HC11 data book as "reserved" or are 
not documented at all (e.g. $1063). It seems N/D left many of the 
original HC11 registers mapped to $1xxx but are using those not 
identified by Motorola.

So the makers can seem to get Motorola to customize the die for each 
application, hence my reference to "ASIC". I considered that the 
function of a register, say, $1063, might be predefined by Motorola 
and the makers would be free to make use of the functions provided 
there, and if so, maybe someone had figured some of them out. They 
just wouldn't fill the rest of the world in on these nifty regs.

> 
> And yes, there are application specific hc11 derivatives that 
> are not available on the general market.
> 

Yup. As I said, the N/D 84-pin PLCC or Delco's 16079434 (what I think 
is the processor :) are clearly, by virtue of the opcodes, running 
with HC11 cores, but they've been heavily massaged by Motorola to 
match the exact requirements of N/D or Delco or whomever.

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?
 
> 
> -- 
> Matthew D. Sale,  IC Development Engineer, Delco Electronics Corp.

<*sigh*> cool job :)

 


- 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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