On Fri, 5 Mar 2010 05:05:11 -0800 (PST), wrote:

On Mar 4, 11:45*pm, "
wrote:
On Thu, 04 Mar 2010 21:42:55 -0500, wrote:
On Thu, 4 Mar 2010 14:44:16 -0800 (PST), wrote:

On Mar 4, 11:05*am, wrote:
On Mar 4, 12:23*am, wrote:

On Wed, 3 Mar 2010 07:49:16 -0800 (PST), wrote:
On Mar 3, 10:06*am, dpb wrote:
wrote:

...

Yes, but you missed my whole point. * You acknowledged that it's
desirable to have some kind of interlock to keep the car from being
shifted into at least Park while it's moving. * OK, so I implement
that system via an interlock system consisting of a solenoid driven by
the computer. * That's right, the same computer that is malfunctioning
and has the throttle pegged. * ...

Automotives don't use simply a single computer -- hence there is no "the
computer". *There are a multitude of very small (and some not so small)
microprocessors. *The likelihood of there being multiple systems on the
same processor is small.

Nonsense. *Sure there are multiple computers in a car. *Common ones
are for the engine control, ABS, climate control, etc. * But nothing
says that one computer cannot be responsible for many systems. *Why
would it seem unusual to have a case where the engine start/shutoff
was in the same computer as that which determines the throttle
position? *It is part of the engine control, is it not? * *And if
there was an electronic shift interlock, why would it be unusual for
that same computer to control it? * That computer is the one that
knows if the car is running, what speed it's traveling at etc.

I don't know what exactly any of the computers in these cars controls
or how the system is put together. * Yet, you among others, are
jumping to conclusions on what is possible or impossible without any
facts.

And in FACT, on most current production vehicles, there is either one
or 2 computers that control everything. Common practice seams to be a
PCM (Powertrain control module) and a BCM (Body control module).
The PCM handles *engine and transmission and all related functions -
often including cruise control, stability control, ABS, etc, while the
BCM handles the AC, power windows, sometimes cruise control etc, and
the instrument panel, among others.

SOME vehicles use only one computer to handle everything (including,
apparently, the RADIO.

Here's a much better source that says you don't know what you're
talking about:

http://www.embedded.com/columns/sign...6?_requestid=5...

For background, embedded processors are the computers that are
embedded in something else, as opposed to being a desktop, notebook,
server, etc. *That something else could be your TV, cell phone,
microwave, or in this case car. *They have a cpu, memory, input/output
and execute a program. * *Here's what they have to say about how many
of these are in cars today and it's even more than I would have
guessed. *I think many here will be surprised at how high the numbers
actually are.

"How many embedded processors does your car have? Go ahead, guess. If
you've got a late-model luxury sedan, two or three processors might be
obvious in the GPS navigation system or the automatic distance
control. Yet you'd still be off by a factor of 25 or 50. The current 7-
Series BMW and S-class Mercedes boast about 100 processors apiece. A
relatively low-profile Volvo still has 50 to 60 baby processors on
board. Even a boring low-cost econobox has a few dozen different
microprocessors in it. Your transportation appliance probably has more
chips than your Internet appliance."

Like I said, there are a lot of "smart switches" in the canbus system
- but although they may use"microprocessors" they are not computers.

Tell us, how is a microprocessor (any microprocessor) *not* a computer?

Yeah, I think everyone wants to know the answer to that question.
It's amazing how when some people are dead wrong on something, instead
of just saying "you're right", they prefer to really make an ass of
themselves.



The microprocessor is used as a switch. Switches are binary digital
devices too - canbus switches are solid state and remote control. They
do NO data processing so are not REALLY computers.

Huh?


Using even a trivial example, where a microprocessor is used as a
switch, then it:

has a CPU
has memory
executes a program
has input and output


That's the basic definition of a computer.

I'd draw the line between hardware implementation of a function and a
"computer" whether or not it has a _stored_program_. How that stored program
is accessible is up for discussion. ;-)

How about I write a
simple assembly language program that implements a switch function,
turning a keyboard light on and off, put it in a flash memory chip,
and replace the bios on my PC with it? The light is now flashing.
Is my PC no longer a computer just because it's running a very simple
program?

The computer is not the switch, in this usage anyway. It may control a
switch, but it is not in itself one.

That said, even if you count them, and use a Bimmer as your example
(likely the most over-computerized space-ships in tha galaxy) finding
100 microprocessor controlled devices, muchless microprocessors, would
be a big stretch.

Who should we believe, you or a website dedicated to embedded
control? Let's say they are off by 2X. That's still a long way from
your claim that there are only one or two computers in any car. I'm
still waiting for a source on that.



And counting the display driver on an LCD display as a "computer" is a
real stretch of litterary licence!!!!!- Hide quoted text -


It's no stretch at all if the display is in fact implemented by using
a microprocessor or microcontroller. If it's implemented strictly
via a digital hardware device, ie, it isn't a cpu running a program,
then yes it would be just a display driver. I think the embedded
system development folks know the difference. Some key point are that
it makes sense to use a computer as opposed to just digital logic
because it's cheap, easy to design, re-programmable during
developemt, manufacturing or potentially in the field without changing
the hardware and once you have it in the display, you can then add all
kinds of nifty features because the cpu is already there and can
handle more stuff for free. If you read the article I provided,
they even point to the first use of a Motorolla 6802 microprocessor in
the 1978 cadillac dashboard display to implement the trip computer.

There is a murky area here, which you even alluded to. Is an FPGA a computer?
(no need to answer that