Logic Analyzer Vs. Oscilloscope

I'll second all of that. A logic analyser is useful in very specific circumstances - where one needs to watch a lot of logic states at the same time. This is usually a hardware debugging phase... and if you're careful with the design, you might never need it. (I think I've used one once in 30 years.)

A decent 'scope, however, is a very handy thingy indeed. I like to probe around new boards just to ensure that there's nothing lurking that could bite me. The 'scope needs to have decent bandwidth; there's no point looking for e.g. good rise and fall times if the 'scope is the limiting factor. For the kind of thing I do, I'd say that a 60-100Mhz 'scope is the absolute minimum that's worth having - anything slower is fine for audio, but not too much help with modern digital. Needn't cost an arm and a leg - I bought mine second-hand for $small_sum.

Oh - and a *storage* 'scope is a very, very, very useful thingy.

HTH,

Steve

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Reply to
Steve at fivetrees
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How about using WINE?

~Dave~

Reply to
Dave

Yes it does, although there are a couple annoyances. One is that you must plug in the USB device after the virtual machine is up and running. You can not tell VMWare to just grab an existing USB connection and transfer it to the virtual machine. Disclaimer: My copy of VMWare is one version behind and I have used it Windows hosts only.

Reply to
Roberto Waltman

With an oscilloscope, you can only view one or two lines at a time. With a logic analyzer you can view 8,16 or 32 lines at a time.

Reply to
A Holt

With an analyzer you can only see a logic state. With a 'scope you can see the effects of crosstalk, ringing, risetime, etc.

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Reply to
CBFalconer

Don't even think about doing a PROJECT without BOTH a logic analyzer AND a high sampling rate digital storage oscillocscope.

A PROJECT has defined objectives, a defined budget, a defined schedule and someone who gets upset if ALL are not met.

Now, if you're just dinking around with simple programs that don't use interrupts and don't interact heavily with the environment, you can get by with NEITHER.

Using debugging statements that light leds, output RS232 etc, you can find many simple bugs by inspection of the code.

A simple analog scope with 50MHz or so bandwidth will help you find the stupid mistakes like, signal ain't there, levels messed up, bad timing (if it's repetitive), ringing etc. But it won't tell you jack about the program 'cause the error happens so infrequently that you can't see the trace.

A digital storage scope is a big help when you know what you're looking for and it's simple to trigger on. Yep, that pulse was the right width... Modern scopes have simple logic triggering capability and can trigger on a signal's analog characteristics. You can also trigger a DSO after the fact from your logic analyzer. Can't do that with analog.

A logic analyzer has similar issues. A simple logic analyzer can help with simple addressing issues. But your problem ain't simple, or you'd have found it by inspecting the code. Your problem happens only when input a happens within 25mS of input b, but only on the 344554th execution of the interrupt...on Thursdays. Bottom line is that the triggering capability of your logic analyzer has to be more flexible than your program logic and hardware interaction.

Read that again...A logic analyzer has to have a state machine in the trigger that is at least as complex as the states your hardware and software can muster.

The problems that will keep you up at night just can't be found with a 10MHz scope with a dim tube and a logic analyzer with a single trigger word. These problems come from parts that don't do what the spec sheet sez (or you misinterpreted the spec sheet) or from conditions that you thought would never happen (or failed to anticipate). They can't be found by inspection, cause the interpretation in you head doesn't match what's actually going on (for whatever reason).

If you think you can only afford one, think again. If your budget is that tight, either one you buy will probably be inadequate anyway.

But every lab with a soldering iron already has an oscilloscope...right??

Enough ranting!! Here's what I do. I have a GAL20V8 socketed on a little breadboard with flying probes. I program the trigger algorithm into the 20V8 and use that to trigger my DSO or simple logic analyzer. It's a real PITA to reprogram for each test, but it sure beats not finding the problem.

mike

Reply to
mike

... snip ...

... snip ...

What I want to know is how, using Thunderbird, you managed to remove all references from the headers, and thus break all threading to the original message. Just fouling the subject line is not enough to do this.

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Reply to
CBFalconer

CBFalconer schrieb:

Take a closer look.

Reply to
Andreas Schwarz

Rich Wrote: ...

I use a HP54645D and I still use the LogicPort Analyser when it comes to lots of digital analysis. With 34 channels to go at you just can't beat it (for the price)!. In my opinion its a great little PC tool.

Jim

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Reply to
Jim

I made no overt attempt to do so. Thunderbird seems to think the thread is still intact. ??? mike

Reply to
mike

Can there be any low cost alternative for these? The logic analyzers and oscillopes are pretty expensive? Any other way out, home made pc based logic analyzer??

Reply to
Himanshu Chauhan

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Reply to
dmm

I bought one a few months back and am happy with it. It's the only one I could find that supported Linux.

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Grant Edwards                   grante             Yow!  Maybe we could paint
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Reply to
Grant Edwards

Ebay is your best bet. I picked up a 1630D for about $50 ... with scopes and probes in working order ... shipping was another $50 and that was 3 months ago.

Two years ago I got a dual channel 100Mhz scope for about $230 one of the Tektronics models ... its saved me many a sleepless night in light of the hobby work I do at home

Reply to
samiam

I looked at the site and was unable to figure out what they cost. What do they cost, including S&H in the US?

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Reply to
Allan Adler

Just a warning: I've run into a couple problems recently.

1) Chop mode doesn't work. You can't reliably acquire two or more analog waveforms simultaneously. I reported this bug a couple weeks ago, and I'm _hoping_ they'll have a bug fix out soon, but I haven't actually heard that they're working on it. 2) There's also a problem with the "zoom timebase" feature. If you capture a lot of data (say 100K points), you usually can't zoom in on a portion of the waveform. Sometimes you can, but I've had very little luck with that.

The prices are all listed in the online store. Go to

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Click on the "buy online" link on the main page. Then click on a product line. Clicking on "digital oscilloscopes" gets you here:

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If you put one in your basket and click "checkout", it'll show you shipping costs as well for whatever shipping option you choose. For example, a Bitscope 310 is $495 + $18.43 for standard shipping.

If you're thinking about ordering, send them an e-mail first and ask if they're working on getting chop mode and the zoom timebase working.

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Grant Edwards                   grante             Yow!  .. hubub, hubub,
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Reply to
Grant Edwards

Also take a look at

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. Based in NZ, but I've seen them advertised at saelig.com in the US. I've just been looking at their software (which you can download and run) and I think I like it better than the Bitscope software (but then I'm biased being a NZ'er :).

- Charles

Reply to
Charles Oram

AFAICT, there's no Linux support.

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Grant Edwards

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