Noobe question

[Uriah]

What I want to do is to clip on to a chip on a known good working
board and record the data coming from the chip. Hopefully finding a
steady clock line as a basis. Then using this data for a certain
period of time I will compare this to a non-working board looking for
any chips that don't match up. I would have to put the board in some
kind of loop mode. What kind of hardware would I need to do something
like this? Using labview of course. I would also like to be able to
compare one pin to another looking for linked pins, or pins shorted to
ground or VCC links and high impedance or low impedance pins also. 96
plus pins. Is there a particular PCI board that can do something like
this? I am just not sure what to buy before jumping in. Any ideas.
Thanks
Uriah

[Conseils]

A lot of testing of this type tends to be done with an associated product known as TestStand.

That's not to say you can't or shouldn't use LabVIEW of course but you would have to ask yourself how appropriate each tool would be in your specific instance.

The case history below should give you a good idea of a typical set up that could also be used in LabVIEW, but I think the first step would be a detailed document defining what the specific goals of the test are. This will enable you to more precisely define the hardware requirements. At its simplest level and with some simple additional circuitry, one could envisage quite a sophisticated test stand with something as simple as the USB 6008.

To help focus on areas one might start an analysis, typically carrying out something like an FMEA (Failure Mode Effects Analysis), perhaps one already exists. The outputs from this can then be used to identify those issues that most need addressing and provide the optimum cost benefit to meet the needs of the business.

Hope this puts you on the right track

Main site
http://www.ni.com/teststand/

Overview
http://zone.ni.com/devzone/cda/tut/p/id/4808

Case history example
http://sine.ni.com/csol/cds/item/vw/p/id/646/nid/124300
http://zone.ni.com/devzone/cda/tut/p/id/5687

[Uriah]

Thank you very much. You have given me a lot to work with so I will
dig in and see what comes of it.
Thanks
Uriah

[Dennis_Knutson]

My very first exposure to automatic test equipment, 30+ years ago, used the exact same approach. You can accomplish this with some basic digital I/O. You need enough for the stimulus and the number of points you need to sense. The problem is that you can only use this for really basic digital designs. Once you start adding processors and other programmable devices, you run into problems. For one, you might have to run the i/o at system speed. This will drive up the cost of the external hardware. Another is the complexity of generating the correct stimulus patterns. It's not enough to simply throw a bunch of random 1's and 0's to the input pins of the UUT. Having the ability to simulate the circuit and output the results can be extremely helpful. You might also have physical problems with using a 'clip'. While that was reasonably effective years ago when everything was 14 and 16 pin DIPs on 100 mil centers, those are pretty rare today.

You might want to investigate a more modern approach. If you are manufacturing a reasonable number of boards, doing an ICT (In-Circuit Test) on the board will test all components, locate all shorts and opens in a fraction of the time, and with greater accuracy than your technique. Fixturing and programming is pretty expensive, though. A lower cost alternative is something called flying probe. A large percentage of contract manufacturers that build and stuff boards will offer both. For a bench test, you should also look at JTAG. A brief overview can by found on Wikepedia.