Maker Pro
Maker Pro

weird reboots of embedded pc

J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that john jardine
I'm not sure what "embedded" refers to nowadays

The army gets to tell you what you can say and what you can't.
 
K

keith

Jan 1, 1970
0
I read in sci.electronics.design that john jardine


The army gets to tell you what you can say and what you can't.

No, that's "enlisted". ...and nothing has changed.
 
P

Pooh Bear

Jan 1, 1970
0
Quack said:
Hi,

This is a verry strange one :)

< snip >

Actually there's nothing stange about it at all. You simply need to design for
EMC.

Chances are that the humidity was high when you didn't have a problem. I guess
the air has dried and now there's static about, you're seeing the weaknesses of
the design.

In Europe ( and elsewhere ) we have to design to withstand electrostatic
discharges or we can't legally sell our kit.


Graham
 
R

Rich Grise

Jan 1, 1970
0
Unix, ta, makes more sense now.
I'm not sure what "embedded" refers to nowadays

Well, back when I was young and doing this sort of thing, embedded meant
that the processor is buried somewhere inside of equipment that doesn't
have to look like a desktop PC at all. The most trivial examples would be
the microwave oven and the VCR. Cars have embedded processors these days.
but occasionally a query
will come in for some kind of industrial machine controller that is easily
and cheaply satisfied by use of a standard PC running just DOS.

This is just a PC that's being used for some kind of control function.

If it looks like a PC, it's not embedded.

Hope This Helps!
Rich
 
M

Mike Monett

Jan 1, 1970
0
Guy Macon wrote:

[...]

Either you got lucky, or your "standard PC" was by a company such
as Compaq which was making PCs to the high quality levels needed
for embedded work back then (today's Compaq / HP hybrid is another
matter). Try that with a modern asian motherboard and you are
unlikely to see it survive to its 5th birthday.


You should have worries.

[...]

What would you suggest for a hard disk drive? Most of the hi-rel ones I'm
aware of are only warranteed for three years.

Best Wishes,

Mike Monett
 
J

john jardine

Jan 1, 1970
0
Guy Macon said:
While I agree 100% about DOS, I strongly disagree with your conclusion
that a standard PC is OK for an embedded system. It simply will not
meet any reasonable requirements for reliability or durability.

Ah! but what is a 'reasonable requirement'?. If I was knocking up mil' spec'
gear, then a PC could be a nightmare. Most applications dont' require shock,
dust, temp' and vibration. Even then, an external enclosure can solve most
environmental problems. Don't know about you but for home and work, I've
been buying and using PC's for 15 years and not one has had a hardware
failure. That's more than can be said for the fancy electronic test
equipment I use.
In the system described, the "real world black box stuff" is the
embedded system. The PC is filling the role of a desktop PC, which
is what it is good at.

Yes, Rich also clarified this. I'd mentally deleted the word after noticing
sales people pick up on it a few years ago.
Either you got lucky, or your "standard PC" was by a company such
as Compaq which was making PCs to the high quality levels needed
for embedded work back then (today's Compaq / HP hybrid is another
matter). Try that with a modern asian motherboard and you are
unlikely to see it survive to its 5th birthday.


You should have worries.

I dropped lucky!. That one was a chinese clone bought from the shop down the
road. But ... I enjoy a walk on the wild side, and I've pushed my luck a
few times since :).
Years ago, a previous employer was planning to buy a PC. The company had
just been bought out and word came down from some imperial, corporate I.T.
section that we must buy a quality 'named' PC. Shelled a barrowload of money
out for a Compaq. Yes, for the money we got good quality casings,
components and circuit cards. We also got a non standard PC, that locked us
in to Compaq for the next 2 years.
Compaq had made enormous effort to enginner the PC to be just capable of
running mainstream PC progs' yet not allow any part of it to be upgraded
without having to buy expensive and inferior Compaq parts. We ditched it a
the first opportunity. Lesson learnt for the future.
That is the wise choice. Have you used a scope to look at the
noise and timing margins on the motherboards that are shipping
nowdays?

Yes I have. The logic is so noisy the signals are invisible.
I'm in a minority here but I prefer to use equipment that has withstood the
major tests of time and mass production.
Doesn't matter how cheap it appears, or how few bits it uses, or how noisy
the electrics are. I know it'll work and carry on working.
Like my HP printer is absolute crap quality but just runs and runs. Yet
those beautifully engineered IBM golfballs and line printers used to break
down weekly.
If your PC104 has any special requirements, then something
is wrong. It should act just like any other PC.


$300 will get you a fine 386SX PC104 stack. That's three
hours of my time at my standard consulting rate.

Last time I looked (UK) they were over £300. Hopefully the prices are
dropping.
I envy being able to charge an hourly rate thing :). Round here the buggers
won't stand for it. They demand a fixed price quote for all jobs, start to
finish. Tricky but can have its upsides.
If your PC104 isn't standard, then something is wrong.
It should act just like any other PC.

I agree yes it should. I'm jaundiced though by the knowledge that given even
a remote chance, any specialist supplier will (dutifully!) try and lock a
user in. Last thing they want is to compete only on price. The earlier
Compaq was advertised and sold as standard, but wasn't.
If your PC104 locks you in, then something is wrong.
You should be able to replace it with any PC104 board.


I have no idea what you are getting at here. PC104s use standard
parts such as Intel 386SX or 386EX - parts that Intel will be
cranking out long after they stop making the latest Pentium X.
It's this non-standard-standard thing again. I've no choice now but what I
didn't want, is to buy some companies industrial PC type gear and then
discover much later down the line that the makers by clever engineering have
subtlely managed to pull a fast one.
I never ever, want to be in the disasterous position that posters here some
times indicate. eg "Having customer returns problems when using an Acme
Mk4/b2 message translator unit being driven by a Putzin model 1234 modem,
fed from a Yanking EZ USB driver. The USB driver company went bust and am
having to use so and so's later version but it don't seem to work the same".

regards
john
 
R

Rich Grise

Jan 1, 1970
0
Guy Macon wrote:

[...]

Either you got lucky, or your "standard PC" was by a company such
as Compaq which was making PCs to the high quality levels needed
for embedded work back then (today's Compaq / HP hybrid is another
matter). Try that with a modern asian motherboard and you are
unlikely to see it survive to its 5th birthday.


You should have worries.

[...]

What would you suggest for a hard disk drive? Most of the hi-rel ones I'm
aware of are only warranteed for three years.

If you're looking at mechanical ruggedness, I'd look at drives that are
designed for laptops.

As far as PC drives, my first Windoze 95 computer, which I bought in about
1996, died about a year ago, but the 4 GB drive is still operating, in a
new used computer from ebay.

If you really want your drives to last a long long time, back up all your
data religiously, so that when it breaks, it doesn't piss you off so bad. ;-)

That would be Murphy at work, of course, much like sitting at a red light
when there's no cross-traffic at all, like at 3 AM. The light waits until
some cross-traffic comes along that it can annoy before it turns your
light green. ;-)

Cheers!
Rich
 
F

Frithiof Andreas Jensen

Jan 1, 1970
0
BTW: QNX is the only system to use with embedded PC
architecture, don't bother with anything else, sorry
Linus.

Go tell that to Linksys - I'm sure they care (not)!

....or here fwiw...

QNX et. al. are for people who want to write Infrastructure - i.e.
Engineers - and that's not The Game anymore.

The real money are made by Integrating what is already there and making it
usable or applicable for "normal people". That vein is only beginning to be
tapped; there would be products for the next 3-5 years even if Linux
development was frozen today, which it is not.
 
G

Guy Macon

Jan 1, 1970
0
Frithiof said:
...


Go tell that to Linksys - I'm sure they care (not)!

I am with Frithiof on this one. QNX is a fine product, but it
is no longer the only game in town, and the various flavors of
Embedded Linux are really outstandingly good.

On the other hand, if I was designing a control system for a
nuclear reactor, I would quit if they didn't let me specify QNX.
 
M

Mark Jones

Jan 1, 1970
0
Guy said:
I am with Frithiof on this one. QNX is a fine product, but it
is no longer the only game in town, and the various flavors of
Embedded Linux are really outstandingly good.

On the other hand, if I was designing a control system for a
nuclear reactor, I would quit if they didn't let me specify QNX.

Curious, out of the different CPU's that are compatible with QNX, is
there a "best" match?
 
G

Guy Macon

Jan 1, 1970
0
Mark said:
Curious, out of the different CPU's that are compatible
with QNX, is there a "best" match?

I haven't studied this question, but I know that as soon as I
can get my hands on a processor and OS that supports the Execute
Disable Bit, I am going to switch top that and never look back.
 
V

Vlad

Jan 1, 1970
0
Hi,

This is a verry strange one :)

The system;
A large cabinet (casino slot machine) - made of wood.
-1 x standard pc motherboard (p4 1.5ghz)
-1 x standard ide disk
-1 x 17" flat panel with resistive touchscreen/usb controlled
-1 x key operated switch, connected to the CDS line of the serial port

The problem;
If someone with a slight static charge touches the key to the keyswitch - it
sometimes hard boots. As if the power was cycled.

We tried changing power supplies.
We tried grounding everything, including the keyswitch.
We tried with everything except power disconnected from the motherboard,
still happens.
(thats right, everything disconnected, including the keyswitch!)

It still happens, even when the keyswitch is completely disconnected - the
keyswitch is also mounted in wood so makes absolutely no connection
anywhere - but for some reason, touching it can reboot the machine.. wow.

Also, there are 10 machines, all worked fine for 3 months - this problem
just 'started' one day - on all 10 machines. So we assumed an external
influence caused it.

So, we replace all motherboards with a different brand - the problem
disappeared.
We added a regulator to feed a UPS for _each_ machine.

This ran for a few weeks - and now the problem has returned. Wow - how
weird!.

any ideas ? this is killing me.

Alex.

Wireless devices like keyboards and mice are not reliable around
airports.

Once I install a radio station that had a power voltage regulator that
behaved in a very strange way. With the transmitter connected to the
dummy load everything was fine, Filtering the line that fed the
control circuit, fixed the problem.

Vlad
 
Q

Quack

Jan 1, 1970
0
Thankyou everyone for your suggestions.
A lot of useful info in there :).

It has been decided to use a standard PC case in the existing machines,
hopefully this will sort it out.
Also we will make a much better attempt at grounding things.

For the future, the enclosures will be made with metalic frames (well
grounded) and _REAL_ embedded boards will be used, no more cheap pc crap :).

The motherboard changes already would have covered the extra cost for using
good quality embedded boards. Oh well. Live and learn :).

Regarding comments about humidity and anti-static carpet spray's, for
obviouse reasons the environment can not be under our direct control all the
time, so whatever we do has to be pretty tough. Other machines seem to
handle it fine.


Thanks again

Alex.
 
P

Pooh Bear

Jan 1, 1970
0
Quack said:
Thankyou everyone for your suggestions.
A lot of useful info in there :).

It has been decided to use a standard PC case in the existing machines,
hopefully this will sort it out.
Also we will make a much better attempt at grounding things.

For the future, the enclosures will be made with metalic frames (well
grounded) and _REAL_ embedded boards will be used, no more cheap pc crap :).

The motherboard changes already would have covered the extra cost for using
good quality embedded boards. Oh well. Live and learn :).

Regarding comments about humidity and anti-static carpet spray's, for
obviouse reasons the environment can not be under our direct control all the
time, so whatever we do has to be pretty tough. Other machines seem to
handle it fine.

Using a metal PC case won't stop ppl discharging themselves into the controls
though !

You need to ensure that the user interface ( touchscreen and switch ) doesn't
allow a path for electrostatic discharges that simply fly through the interface
board and upset the PC's internals.


Graham
 
J

John Perry

Jan 1, 1970
0
Rich Grise wrote:
....
for embedded applications - you'd only need something as high-level as QNX
(which, AFAIK, is just another unix) if you're doing some massive

OUCH!

At least as far along as QNX4 (the last version I used), the only
relationship between QNX and unix was deliberately superficial. QNX used
the superficial appearance to unix to ease transition of programmers to
QNX, and used a completely unrelated substructure to gain reliability,
speed, and real-time response far beyond anything any "standard" OS is
capable of.

A similar self-hosted system is OS-9 from Microware; there are many
cross-hosted systems that are supposed to be about as good. I only have
direct experience with QNX and OS-9, though.
 
R

Rolavine

Jan 1, 1970
0
Subject: Re: weird reboots of embedded pc
From: John Perry [email protected]
Date: 12/22/04 7:38 PM Pacific Standard Time
Message-id: <N2ryd.4583$ce6.3669@lakeread07>

Rich Grise wrote:
...

OUCH!

At least as far along as QNX4 (the last version I used), the only
relationship between QNX and unix was deliberately superficial. QNX used
the superficial appearance to unix to ease transition of programmers to
QNX, and used a completely unrelated substructure to gain reliability,
speed, and real-time response far beyond anything any "standard" OS is
capable of.

A similar self-hosted system is OS-9 from Microware; there are many
cross-hosted systems that are supposed to be about as good. I only have
direct experience with QNX and OS-9, though.
Why not run DOS? It's real time enough for most applications, and the last
versions of it, as well as the development tools, were reliable as can be.

Rocky
 
Top