Microprocessor question

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I have a question that I hope someone on here can answer, or give me
an insight:

1. Is there any way to do a quick check on a microprocessor to
determine if it's "alive"? I realize manufacturers use million-dollar
testers for functional testing, but is there a way to "generically" do
a quick check on the bench using standard test equipment?

2. Ditto for speed? How can one determine if a microprocessor will run
at its marked speed on a bench?

3. If there is a "generic" feature set that is common to most
microprocessors, and what might that be?

4. How can one check for this - as far as hardware and software
requirements?

I guess I am looking for a "generic" test setup that can do something
like a bare-bones electrical QC on different microprocessor families.

Thanks for your help.

Gary

 

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gary s <gary_s@REMexcite.com> wrote in message news:<qfetn0tohn45q767g4okh70obnol7g9a1f@4ax.com>...
> I have a question that I hope someone on here can answer, or give me
> an insight:
>
> 1. Is there any way to do a quick check on a microprocessor to
> determine if it's "alive"? I realize manufacturers use million-dollar
> testers for functional testing, but is there a way to "generically" do
> a quick check on the bench using standard test equipment?
>
> 2. Ditto for speed? How can one determine if a microprocessor will run
> at its marked speed on a bench?
>
> 3. If there is a "generic" feature set that is common to most
> microprocessors, and what might that be?
>
> 4. How can one check for this - as far as hardware and software
> requirements?
>
> I guess I am looking for a "generic" test setup that can do something
> like a bare-bones electrical QC on different microprocessor families.
>
> Thanks for your help.
>
> Gary

Do you have a known "good" board?

If so, you can probe around with an oscope and you will get some
repeatible waveforms. Now go to your "bad" board and do an A-B
comparison. With some trial and error you will find some waveforms
(pins) that will give you a "state-of-health". And this without
knowing anything about the processor or application.

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

Hi Gary,

>1. Is there any way to do a quick check on a microprocessor to
>determine if it's "alive"? I realize manufacturers use million-dollar
>testers for functional testing, but is there a way to "generically" do
>a quick check on the bench using standard test equipment?
>
>
Tough. The only crude way I have used in the past is a coil placed on
top of it in a precisely repeatable position and looking at the
spectrum. But that is crude and only comparative. I just needed it to
see if something was running on it and to figure out if any of the
spectrum would be synchronous to noise I was chasing.

>2. Ditto for speed? How can one determine if a microprocessor will run
>at its marked speed on a bench?
>
>
Only via a full electrical test, since all its functions must keep up at
the rated speed.

>3. If there is a "generic" feature set that is common to most
>microprocessors, and what might that be?
>
>
For me it is the noise spectrum emitted from the enclosure and the lines
but that is different for every processor and circuit board. Kind of
like submarine guys who are able to determine what kind of vessel is
cruising above just from hearing its noise.

>4. How can one check for this - as far as hardware and software
>requirements?
>
>I guess I am looking for a "generic" test setup that can do something
>like a bare-bones electrical QC on different microprocessor families.
>
>
It'll be different for every processor and you would have to obtain the
QC procedure from the manufacturer, if they are willing to share it for
incoming QC purposes.

Regards, Joerg

http://www.analogconsultants.com

 

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On Tue, 26 Oct 2004 15:58:38 -0500, gary s wrote:

> I have a question that I hope someone on here can answer, or give me
> an insight:
>
> 1. Is there any way to do a quick check on a microprocessor to
> determine if it's "alive"? I realize manufacturers use million-dollar
> testers for functional testing, but is there a way to "generically" do
> a quick check on the bench using standard test equipment?

Use a scope. The clock should be clocking, and the address, data, and
control lines will all be going up and down, assuming it's executing
something.

Issue a reset, and you should see some kind of change in the waveforms.

>
> 2. Ditto for speed? How can one determine if a microprocessor will run
> at its marked speed on a bench?

Build up the circuit, and test it. I think it's extremely unlikely that
you'll get one that doesn't meet its own spec.

If you're at the chip factory, and they're chips coming off the line,
then shame on you! ;-)

>
> 3. If there is a "generic" feature set that is common to most
> microprocessors, and what might that be?

More or less - they have all the features of a processor. Clock,
address, data, ALU, some control logic. Other than that, it's a
free-for-all. ;-)

>
> 4. How can one check for this - as far as hardware and software
> requirements?

In-circuit test is the only way to really verify the whole thing,
and this shouldn't be in the end item, but a dedicated bench
fixture with some diagnostic firmware and misc. peripherals and
stuff, which will depend on your needs there.

> I guess I am looking for a "generic" test setup that can do something
> like a bare-bones electrical QC on different microprocessor families.
>
I'm afraid each family will need its own tester, or at least personality
modules.

I don't even know if any manufacturers sell different versions that are
plug-compatible, except maybe versions of the HC11 or so. But from
one manufacturer to another, they're different enough that this would
be a wild goose chase.


> Thanks for your help.

Sorry I couldn't be more helpful.

Good Luck!
Rich

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

gary s <gary_s@REMexcite.com> wrote in message news:<qfetn0tohn45q767g4okh70obnol7g9a1f@4ax.com>...
> I have a question that I hope someone on here can answer, or give me
> an insight:
>
> 1. Is there any way to do a quick check on a microprocessor to
> determine if it's "alive"? I realize manufacturers use million-dollar
> testers for functional testing, but is there a way to "generically" do
> a quick check on the bench using standard test equipment?

Just use a scope and look for square waves on various pins of the
micro. That will tell you something is happening, maybe correct,
maybe not. If you don't have a scope, use a DMM to measure the
DC voltage on various pins. The DC voltage will vary from 0 to 5 volts
or 0 to the power supply voltage indicating something is happening on
that particular pin. But it's hard to tell exactly what is going on
without knowing the program. And then it would be difficult to
interpret the digital signals from the program. If you have a good
micro, you can compare the waveforms of the test micros to the known
good micro and usually identify the problems.

>
> 2. Ditto for speed? How can one determine if a microprocessor will run
> at its marked speed on a bench?

You probably need to use a external clock to drive the micro
at the rated speed or greater.

> 3. If there is a "generic" feature set that is common to most
> microprocessors, and what might that be?

A generic feature would be the number of I/O lines and internal
program RAM and ROM available.

>
> 4. How can one check for this - as far as hardware and software
> requirements?

Is this a homework problem?

>
> I guess I am looking for a "generic" test setup that can do something
> like a bare-bones electrical QC on different microprocessor families.
>

You need different tests for different processors. The pin assignments
will be different, so you have to look at different pins for different
activity of different processors.

-Bill

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

In comp.sys.ibm.pc.hardware.chips gary s <gary_s@remexcite.com> wrote:
> 1. Is there any way to do a quick check on a microprocessor
> to determine if it's "alive"? I realize manufacturers use
> million-dollar testers for functional testing, but is there
> a way to "generically" do a quick check on the bench using
> standard test equipment?

Of course. Plug it into a known-good mobo, fix a heatsink
& boot.

> 2. Ditto for speed? How can one determine if a microprocessor
> will run at its marked speed on a bench?

Leave booted for a while and watch for lockups.
You could try running one of my cpuburn utils

> 3. If there is a "generic" feature set that is common to
> most microprocessors, and what might that be?

Yes, the x86 instructions set is common to all x86
processors. At least the original IBM PC BIOS tested
some basic functionality.

> 4. How can one check for this - as far as hardware and
> software requirements?

There are pgms that will check operations.

> I guess I am looking for a "generic" test setup that can
> do something like a bare-bones electrical QC on different
> microprocessor families.

JTAG might work if you've got the money.

-- Robert

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

If you're testing older processors such as the Z-80 and the 6502, you could
buy some cheap PCs such as the TRS-80 (Z-80), an Apple II (6502), a Radio
Shack Color Computer (6809) and/or an original Macintosh (68000) and use the
sockets on the motherboards or install one if not already provided. Then
just use each computer as a test bench.

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

Thanks for all the prompt replies I've seen so far.

I work for a reseller, and my company acts as the broker for large
batches of different types of microprocessors bought on the "gray"
market to meet production shortages. There is no longer any
manufacturer's warranty, therefore there is a desire to screen out
parts that are dead, slow, or counterfeit. It appears there are folks
out there who are making a living remarking slow parts, or assembling
parts that have been scrapped off the manufacturer's production
line...

I've been told that after a microprocessor leaves the manufacturer,
there is really no way to test it except on a motherboard/application
board (or some kind of evaluation board). My customers are doing this
after their assembly process. But it would be nice to have some kind
of meaningful acceptance testing at my end before they get the part.

I've received suggestions that (1) maybe there is a way to see if the
thing wiggles (the assumption is if you can wiggle it (maybe getting
it in and out of reset?), it's probably good - or there is a live chip
inside anyway), and (2) maybe there is a way to do something like
adding 2 and 2 (or loop on something) to see if the thing can perform
at the advertised speed.

Evidently I would need the services of an EE to attempt something like
this. And if this "generic microprocessor checker" can be built, I
suspect it's going to be a challenge mechanically, owing to all the
different pin-outs and package types. I just wanted to know from the
experts on here if this is something that is worth pursuing, or
proposing to my management.

Thanks again -

Gary

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

"gary s" <gary_s@REMexcite.com> wrote in message
news:k7qtn0lclsqhurcvlm0pnsa10jp5ov38hq@4ax.com...
> Thanks for all the prompt replies I've seen so far.
>
> I work for a reseller, and my company acts as the broker for large
> batches of different types of microprocessors bought on the "gray"
> market to meet production shortages. There is no longer any
> manufacturer's warranty, therefore there is a desire to screen out
> parts that are dead, slow, or counterfeit. It appears there are folks
> out there who are making a living remarking slow parts, or assembling
> parts that have been scrapped off the manufacturer's production
> line...
>
> I've been told that after a microprocessor leaves the manufacturer,
> there is really no way to test it except on a motherboard/application
> board (or some kind of evaluation board). My customers are doing this
> after their assembly process. But it would be nice to have some kind
> of meaningful acceptance testing at my end before they get the part.
>
> I've received suggestions that (1) maybe there is a way to see if the
> thing wiggles (the assumption is if you can wiggle it (maybe getting
> it in and out of reset?), it's probably good - or there is a live chip
> inside anyway), and (2) maybe there is a way to do something like
> adding 2 and 2 (or loop on something) to see if the thing can perform
> at the advertised speed.
>
> Evidently I would need the services of an EE to attempt something like
> this. And if this "generic microprocessor checker" can be built, I
> suspect it's going to be a challenge mechanically, owing to all the
> different pin-outs and package types. I just wanted to know from the
> experts on here if this is something that is worth pursuing, or
> proposing to my management.
>
> Thanks again -
>
> Gary
>
What I have done to test a new board is to write a simple program that
executes on power up:
1) write 55 to some memory location
2) write AA to same memory location
3) Read memory location
4 loop back to 1)

Hor an Intel type chip, I also did an IOR and IOW.

This obviously requires different hardware for each type of chip. I don't
see any way around that.

Tam

 

[budgie]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

On Tue, 26 Oct 2004 19:18:31 -0500, gary s <gary_s@REMexcite.com> wrote:

>Thanks for all the prompt replies I've seen so far.
>
>I work for a reseller, and my company acts as the broker for large
>batches of different types of microprocessors bought on the "gray"
>market to meet production shortages. There is no longer any
>manufacturer's warranty, therefore there is a desire to screen out
>parts that are dead, slow, or counterfeit. It appears there are folks
>out there who are making a living remarking slow parts, or assembling
>parts that have been scrapped off the manufacturer's production
>line...
>
>I've been told that after a microprocessor leaves the manufacturer,
>there is really no way to test it except on a motherboard/application
>board (or some kind of evaluation board). My customers are doing this
>after their assembly process. But it would be nice to have some kind
>of meaningful acceptance testing at my end before they get the part.

(snip)

Because of the diversity of types/pinouts I suspect you are chasing the
unachievable unless you have a '70s NASA budget.

What you COULD do is consider moving the client testing into YOUR facility. If
they can provide either end-product or a test jig for the specific micro they
purchase, your outfit could do the testing before on-shipping the chip. That
would relieve them of that burden and give your firm not only confidence in the
shipped part but also a reputation for actually giving a stuff about the client.

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

On Wed, 27 Oct 2004 09:52:49 +0800, budgie wrote:

> On Tue, 26 Oct 2004 19:18:31 -0500, gary s <gary_s@REMexcite.com> wrote:
> [about uP testing]
> Because of the diversity of types/pinouts I suspect you are chasing the
> unachievable unless you have a '70s NASA budget.
>
> What you COULD do is consider moving the client testing into YOUR facility. If
> they can provide either end-product or a test jig for the specific micro they
> purchase, your outfit could do the testing before on-shipping the chip. That
> would relieve them of that burden and give your firm not only confidence in the
> shipped part but also a reputation for actually giving a stuff about the client.

Hear! Hear! This is actually a very good idea.
Guess I'm getting old in my old age. ;-)

Have Fun!
Rich

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

It is not beyond feasible to build a test jig for each microprocessor
family.

For example, I've been messing about learning the 8051 processor family. I
have an EPROM / Flash programmer I bought new from ebay for about $45 which
will program almost everything. My "Test Jig" consists of a prototyping
breadboard into which I've plugged a simple power supply, the processor
(with onboard flash memory), one crystal and 2 capacitors (for the clock)
and a reset switch. You can write a trivial looping program to output a
square wave, program the processor using your PC, use the maximum crystal
frequency, and see if you get a square wave. For processors without onboard
program space you can add an EPROM to the breadboard and blow that instead.
This jig should work for all processors in the 8051 family of the same
package (number of pins). This will indicate the processor can run a basic
function at maximum rated speed. There could be other faults of course
(falty onboard RAM) but it sounds like this simple test is what you need.

If all this sounds too daunting, get a Microprocessor Programming book and
spend a few evenings reading it, and you may find it's well within your own
capability. This isn't rocket science despite appearances.


Gareth.









"gary s" <gary_s@REMexcite.com> wrote in message
news:qfetn0tohn45q767g4okh70obnol7g9a1f@4ax.com...
>I have a question that I hope someone on here can answer, or give me
> an insight:
>
> 1. Is there any way to do a quick check on a microprocessor to
> determine if it's "alive"? I realize manufacturers use million-dollar
> testers for functional testing, but is there a way to "generically" do
> a quick check on the bench using standard test equipment?
>
> 2. Ditto for speed? How can one determine if a microprocessor will run
> at its marked speed on a bench?
>
> 3. If there is a "generic" feature set that is common to most
> microprocessors, and what might that be?
>
> 4. How can one check for this - as far as hardware and software
> requirements?
>
> I guess I am looking for a "generic" test setup that can do something
> like a bare-bones electrical QC on different microprocessor families.
>
> Thanks for your help.
>
> Gary
>
>
>

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

"Gareth Magennis" <sound.service@btconnect.com> wrote in message
news:clnris$c7d$1@titan.btinternet.com...
> It is not beyond feasible to build a test jig for each microprocessor
> family.
>
> For example, I've been messing about learning the 8051 processor
family. I
> have an EPROM / Flash programmer I bought new from ebay for about $45
which
> will program almost everything. My "Test Jig" consists of a
prototyping
> breadboard into which I've plugged a simple power supply, the
processor
> (with onboard flash memory), one crystal and 2 capacitors (for the
clock)
> and a reset switch. You can write a trivial looping program to output
a
> square wave, program the processor using your PC, use the maximum
crystal
> frequency, and see if you get a square wave. For processors without
onboard
> program space you can add an EPROM to the breadboard and blow that
instead.
> This jig should work for all processors in the 8051 family of the same
> package (number of pins). This will indicate the processor can run a
basic
> function at maximum rated speed. There could be other faults of
course
> (falty onboard RAM) but it sounds like this simple test is what you
need.
>
> If all this sounds too daunting, get a Microprocessor Programming book
and
> spend a few evenings reading it, and you may find it's well within
your own
> capability. This isn't rocket science despite appearances.

> Gareth.

You're right about a microcontroller like the 8051. But the common
microprocessor has more than ten times the number of pins, and it's a
lot more than rocket science to get it running without any support
system.


> "gary s" <gary_s@REMexcite.com> wrote in message
> news:qfetn0tohn45q767g4okh70obnol7g9a1f@4ax.com...
> >I have a question that I hope someone on here can answer, or give me
> > an insight:
> >
> > 1. Is there any way to do a quick check on a microprocessor to
> > determine if it's "alive"? I realize manufacturers use
million-dollar
> > testers for functional testing, but is there a way to "generically"
do
> > a quick check on the bench using standard test equipment?
> >
> > 2. Ditto for speed? How can one determine if a microprocessor will
run
> > at its marked speed on a bench?
> >
> > 3. If there is a "generic" feature set that is common to most
> > microprocessors, and what might that be?
> >
> > 4. How can one check for this - as far as hardware and software
> > requirements?
> >
> > I guess I am looking for a "generic" test setup that can do
something
> > like a bare-bones electrical QC on different microprocessor
families.
> >
> > Thanks for your help.
> >
> > Gary
> >
> >
> >
>
>

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

On Wed, 27 Oct 2004 09:59:56 +0000 (UTC), "Gareth Magennis"
<sound.service@btconnect.com> wrote:

>It is not beyond feasible to build a test jig for each microprocessor
>family.
>
>For example, I've been messing about learning the 8051 processor family. I
>have an EPROM / Flash programmer I bought new from ebay for about $45 which
>will program almost everything. My "Test Jig" consists of a prototyping
>breadboard into which I've plugged a simple power supply, the processor
>(with onboard flash memory), one crystal and 2 capacitors (for the clock)
>and a reset switch. You can write a trivial looping program to output a
>square wave, program the processor using your PC, use the maximum crystal
>frequency, and see if you get a square wave. For processors without onboard
>program space you can add an EPROM to the breadboard and blow that instead.
>This jig should work for all processors in the 8051 family of the same
>package (number of pins). This will indicate the processor can run a basic
>function at maximum rated speed. There could be other faults of course
>(falty onboard RAM) but it sounds like this simple test is what you need.
>
>If all this sounds too daunting, get a Microprocessor Programming book and
>spend a few evenings reading it, and you may find it's well within your own
>capability. This isn't rocket science despite appearances.

This is similar to what was suggested to me. My problem is in somehow
"generalizing" this to a superset to include 16 and 32-bit parts with
hundreds of pins.

Thanks -

Gary

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

"gary s" <gary_s@REMexcite.com> wrote in message
news:qfetn0tohn45q767g4okh70obnol7g9a1f@4ax.com...
> I have a question that I hope someone on here can answer, or give me
> an insight:
>
> 1. Is there any way to do a quick check on a microprocessor to
> determine if it's "alive"?

Most single chip micros will configure all the pins as inputs on Reset/POR.
Early in the code the programmer has to configure the pins to be inputs or
outputs. If you see all the pins floating or pulled hi/low by external
components then it probably hasn't executed that early code. If we are
talking about a new flash programmable part then it's also possible someone
forgot to program it (eg it's still blank!).

 

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"gary s" <gary_s@REMexcite.com> wrote in message
news:k7qtn0lclsqhurcvlm0pnsa10jp5ov38hq@4ax.com...

> My customers are doing this after their assembly process.

Please let us know who your customers are so we can avoid buying from them!

 

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On Wed, 27 Oct 2004 19:24:05 GMT, "CWatters"
<colin.watters@pandoraBOX.be> wrote:

>
>"gary s" <gary_s@REMexcite.com> wrote in message
>news:k7qtn0lclsqhurcvlm0pnsa10jp5ov38hq@4ax.com...
>
>> My customers are doing this after their assembly process.
>
>Please let us know who your customers are so we can avoid buying from them!

Chances are you have something in your house from one of my customers.
But rest assured their outgoing QC is 100%.

A lot of my inventory comes from OEMs in sealed, virgin condition so
there is little that needs to be done. There is a huge market for
excess and obsolete parts, and there is always a demand somewhere for
them. Unfortunately, it is the stuff of questionable pedigree that's
giving everybody headaches.

Regards -

Gary

 

[Guest]

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"gary s" <gary_s@REMexcite.com> wrote in message
news:qfetn0tohn45q767g4okh70obnol7g9a1f@4ax.com...
> I have a question that I hope someone on here can answer, or give me
> an insight:
>
> 1. Is there any way to do a quick check on a microprocessor to
> determine if it's "alive"? I realize manufacturers use million-dollar
> testers for functional testing, but is there a way to "generically" do
> a quick check on the bench using standard test equipment?
>
> 2. Ditto for speed? How can one determine if a microprocessor will run
> at its marked speed on a bench?
>
> 3. If there is a "generic" feature set that is common to most
> microprocessors, and what might that be?
>
> 4. How can one check for this - as far as hardware and software
> requirements?

Elektor magazine had a suggestion way back: fill a memory with NOP's
suitable for the processor. If everything is working, you should see halving
the frequency on every higher address line. And you may use a variable clock
source to see when things start to go wrong.

Wim

 

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Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

On Tue, 26 Oct 2004 20:13:23 -0700, Tom Seim wrote:

> gary s <gary_s@REMexcite.com> wrote in message news:<qfetn0tohn45q767g4okh70obnol7g9a1f@4ax.com>...

>> Thanks for your help.
>>
>> Gary
>
> Do you have a known "good" board?
>
> If so, you can probe around with an oscope and you will get some
> repeatible waveforms. Now go to your "bad" board and do an A-B
> comparison. With some trial and error you will find some waveforms
> (pins) that will give you a "state-of-health". And this without
> knowing anything about the processor or application.

I believe you've just invented the "signature analyzer."

Cheers!
Rich

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

Yes, sorry about that, I was assuming the poster was talking
microcontrollers in consumer equipment rather than big computing systems. I
see a lot of this stuff.



>
> You're right about a microcontroller like the 8051. But the common
> microprocessor has more than ten times the number of pins, and it's a
> lot more than rocket science to get it running without any support
> system.
>
>

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

Good reason to stay away from "independent" distributors - No
warranty, suspicious circumstances re how they get their product.
Stick with the "franchised" distributors. They get their parts
directly from manufacturers. They also receive full technical support
from manufacturers (as opposed to having to ask questions on Usenet)

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

> 1. Is there any way to do a quick check on a microprocessor to
> determine if it's "alive"? I realize manufacturers use million-dollar
> testers for functional testing, but is there a way to "generically" do
> a quick check on the bench using standard test equipment?

What you have in mind is a real challenge! A semiconductor
manufacturer is happy, if the test coverage exceeds 95% of all the
nodes inside the chip. That means that roundabout 5% of the chip
remains untested. And that is done with very sophisticated and
expensive test equipment, which can access the internal test logic. In
addition to the very fundamental IDDq test (measuring the qiescent
current), this results in a failure rate of a few ppm at the customer.

Without access to the test structures inside the device and without
thorough understanding of its design, you will hardly ever test more
than a third of the device with any test software. The other simple
tests which have been proposed here in other posts, will probably not
cover more than just 5 to 10% of the device.

One can find about 70% of all possible failures by means of dedicated
test software. We have done that for a 32-bit RISC CPU. It requires
the RTL description of the device and many days of simulation time per
iteration on expensive machines with even more expensive software.

The most simple test that you could do is the IDDq test (assuming the
device is CMOS and fully static). Measure the current consumption of
the device during Reset and then clock the device slowly. Measure the
static current after each clock edge. If it is more than the specified
leakage current, then discard the device. This test can find more than
50% of all possible bugs and therefore it is better than most test
software (which would still increase the coverage though). The idea
behind the IDDq test is that a failure will probably be caused by a
gate that is stuck at high or stuck at low, i.e. a transistor that is
constantly switched on or off. If the other transistor switches on,
then a short circuit exists and the leakage current is increased. Note
that such a short doesn't draw amps, but microamps...

> 2. Ditto for speed? How can one determine if a microprocessor will run
> at its marked speed on a bench?

Run the device at nominal conditions (specified voltage and room
temperature) and use 1.5 times the specified clock frequency. That
should assure that the device works at minimum voltage and maximum
temperature at the specified speed.

I hope that helps.

Michael

 

[budgie]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

On Wed, 03 Nov 2004 15:32:34 -0600, geneguy <gene@nothx.biz> wrote:

>Good reason to stay away from "independent" distributors - No
>warranty, suspicious circumstances re how they get their product.
>Stick with the "franchised" distributors. They get their parts
>directly from manufacturers.

Not always the case. Here in down-under-land, Maxim (as one example, also
LinearTechnology) are officially distibuted by Arrow Electronics Australia,
AFAIK a wholly owned subsidiary of Arrow Electronics in the U.S. Arrow Aus
order through Arrow in U.S. who in turn order from the factory. While that
distinction may sound minor, the US-based parent won't move until it has factory
MOQ orders in hand from its downstream. That means we can wait an indefinite
time for parts through "our" franchised distributor simply because of their
organisational structure. We had to wait 14 weeks for a Maxim eval kit that
was ex-stock Maxim throughout the entire waiting period because of this "food
chain". We also have to order factory MOQ as this sytem does not warehouse or
break down factory MOQ at any point.

As an alternative, there is a Maxim distributor next door (in N.Z.) who doesn't
seem to have the same hangups. His delivery is typically a couple of weeks vs
many months via the "official" chain - AND we get to order 20 chips instead of
500. So when we needed 20 chips for a pre-production run, guess which small
distributor got the business.

>They also receive full technical support
>from manufacturers (as opposed to having to ask questions on Usenet)

Not with Arrow Aust. If it isn't on the chip manufacturer's website then you
may as well forget it - or ask on usenet. Maybe they aren't representative of
authorised/franchised distributors elsewhere, but they certainly don't support
your model.

 

[Guest]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

On Thu, 04 Nov 2004 09:35:17 +0800, budgie <me@privacy.net> wrote:

>On Wed, 03 Nov 2004 15:32:34 -0600, geneguy <gene@nothx.biz> wrote:
>
>>Good reason to stay away from "independent" distributors - No
>>warranty, suspicious circumstances re how they get their product.
>>Stick with the "franchised" distributors. They get their parts
>>directly from manufacturers.
>
>Not always the case. Here in down-under-land, Maxim (as one example, also
>LinearTechnology) are officially distibuted by Arrow Electronics Australia,
>AFAIK a wholly owned subsidiary of Arrow Electronics in the U.S. Arrow Aus
>order through Arrow in U.S. who in turn order from the factory. While that
>distinction may sound minor, the US-based parent won't move until it has factory
>MOQ orders in hand from its downstream. That means we can wait an indefinite
>time for parts through "our" franchised distributor simply because of their
>organisational structure. We had to wait 14 weeks for a Maxim eval kit that
>was ex-stock Maxim throughout the entire waiting period because of this "food
>chain". We also have to order factory MOQ as this sytem does not warehouse or
>break down factory MOQ at any point.
>
>As an alternative, there is a Maxim distributor next door (in N.Z.) who doesn't
>seem to have the same hangups. His delivery is typically a couple of weeks vs
>many months via the "official" chain - AND we get to order 20 chips instead of
>500. So when we needed 20 chips for a pre-production run, guess which small
>distributor got the business.

I myself have used independent distributors to cover small-quantity
shortages as the original poster mentioned. Other OEMs do the same -
their buyers do this "under the table" so to speak (off the approved
vendor list). If the material is in original boxes then you can safely
say it's ok. All bets are off if the seal has been broken. I had one
batch with dead parts once. Failure analysis showed wrong die inside -
the outside marking was bogus.

>>They also receive full technical support
>>from manufacturers (as opposed to having to ask questions on Usenet)
>
>Not with Arrow Aust. If it isn't on the chip manufacturer's website then you
>may as well forget it - or ask on usenet. Maybe they aren't representative of
>authorised/franchised distributors elsewhere, but they certainly don't support
>your model.

By contractual agreement franchised distributors can refer their
customers to manufacturers for technical support (because the
questions tend to be application-specific and distributors are just
basically warehouses), and manufacturers are pretty supportive about
it in my experience. Independent distributors are not recognized by
manufacturers. As a matter of fact independent distributors are often
considered the cowboys of the industry, peddling parts of unknown
origin. Having said that, there is a place for them in the food chain.
You just have to be really careful.

 

[budgie]

Archived from groups: sci.electronics.design,sci.electronics.basics,sci.electronics.components,sci.electronics.misc,comp.sys.ibm.pc.hardware.chips (More info?)

On Thu, 04 Nov 2004 15:41:37 -0600, geneguy <gene@nothx.biz> wrote:

>On Thu, 04 Nov 2004 09:35:17 +0800, budgie <me@privacy.net> wrote:
>
>>On Wed, 03 Nov 2004 15:32:34 -0600, geneguy <gene@nothx.biz> wrote:
>>
>>>Good reason to stay away from "independent" distributors - No
>>>warranty, suspicious circumstances re how they get their product.
>>>Stick with the "franchised" distributors. They get their parts
>>>directly from manufacturers.
>>
>>Not always the case. Here in down-under-land, Maxim (as one example, also
>>LinearTechnology) are officially distibuted by Arrow Electronics Australia,
>>AFAIK a wholly owned subsidiary of Arrow Electronics in the U.S. Arrow Aus
>>order through Arrow in U.S. who in turn order from the factory. While that
>>distinction may sound minor, the US-based parent won't move until it has factory
>>MOQ orders in hand from its downstream. That means we can wait an indefinite
>>time for parts through "our" franchised distributor simply because of their
>>organisational structure. We had to wait 14 weeks for a Maxim eval kit that
>>was ex-stock Maxim throughout the entire waiting period because of this "food
>>chain". We also have to order factory MOQ as this sytem does not warehouse or
>>break down factory MOQ at any point.
>>
>>As an alternative, there is a Maxim distributor next door (in N.Z.) who doesn't
>>seem to have the same hangups. His delivery is typically a couple of weeks vs
>>many months via the "official" chain - AND we get to order 20 chips instead of
>>500. So when we needed 20 chips for a pre-production run, guess which small
>>distributor got the business.
>
>I myself have used independent distributors to cover small-quantity
>shortages as the original poster mentioned. Other OEMs do the same -
>their buyers do this "under the table" so to speak (off the approved
>vendor list). If the material is in original boxes then you can safely
>say it's ok. All bets are off if the seal has been broken. I had one
>batch with dead parts once. Failure analysis showed wrong die inside -
>the outside marking was bogus.
>
>>>They also receive full technical support
>>>from manufacturers (as opposed to having to ask questions on Usenet)
>>
>>Not with Arrow Aust. If it isn't on the chip manufacturer's website then you
>>may as well forget it - or ask on usenet. Maybe they aren't representative of
>>authorised/franchised distributors elsewhere, but they certainly don't support
>>your model.
>
>By contractual agreement franchised distributors can refer their
>customers to manufacturers for technical support (because the
>questions tend to be application-specific and distributors are just
>basically warehouses), and manufacturers are pretty supportive about
>it in my experience. Independent distributors are not recognized by
>manufacturers. As a matter of fact independent distributors are often
>considered the cowboys of the industry, peddling parts of unknown
>origin. Having said that, there is a place for them in the food chain.
>You just have to be really careful.

Our experiences certainly differ. After waiting over three months for the "ex
stock" Maxim eval-kit, we commenced our product design in parallel with
evaluating the eval-kit. (Normally these would have been sequential but we had
lost 12 weeks).

A couple of complex design questions arose. I wasn't about to waste more time
dealing with/through the franchised distributor. I just fired emails into Maxim
tech support. They neither asked nor presumably cared where the parts were
sourced. I got exceptional one-to-one tech/design support.

We don't go down dark alleys seeking cheaper sources. We use known (and
long-standing) suppliers but don't get hung up on where they stand in the
official food chain. And we DON'T go anywhere near Arrow Aust any more.