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2006-05-24 by Anurag Chugh
2006-05-24 by Larry Barello
No experience, but 2048 samples seems a bit shallow. I am using the Cleverscope, which is NOT a logic analyzer, but has a 2 mega-sample deep buffer. They claim they are adding protocol decode & triggering which will help me out immensely when it is available. As it is I can trigger on simple logic state (e.g. I2C start or stop conditions) which gets me pretty close to the data and I am getting pretty good at interpreting the logic signals looking for problems. It is nice to be able to capture .25 seconds of data (many poll cycles) and still maintain enough resolution to resolve timing problems.
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Larry Barello
www.barello.net
From:
AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf Of Anurag Chugh
Sent: Wednesday, May 24, 2006
12:12 AM
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Logic Analyzer
Hello everyone.
I was thinking of buying a Logic Analyser for developing some extensive AVR applications.
I wanted to know what you guys feel about http://www.pctestinstruments.com/index.htm
Have anyone of you have any experience with this beauty?
Is it worth the buy?
Thanking you all.
Anurag Chugh
VU2AXC
2006-05-24 by Ned Konz
Anurag Chugh wrote: > Hello everyone. > I was thinking of buying a Logic Analyser for developing some extensive > AVR applications. > I wanted to know what you guys feel about > http://www.pctestinstruments.com/index.htm > > Have anyone of you have any experience with this beauty? > > Is it worth the buy? I'm sure that Larry Barello will pitch in, as he's recently gotten a Cleverscope. I flooded him with a lot of info about the solutions from Agilent and Tek that were available on eBay. I haven't used this LA (haven't seen it before, actually), but these points stand out for me: * Proprietary interface? I wouldn't get a PC-based instrument that didn't have a documented over-the-wire interface, or at least a documented interface to driver libraries (this is a distant second, as anyone who's had to update operating systems can tell you). As I see it, one of the advantages of PC-based instruments is the ability to make customized data analysis tools. For this you need some way to get the data out. Unlike a stand-alone instrument, unless you're willing to dedicate a computer to being a logic analyzer interface, you're going to want to upgrade your operating system from time to time. And if your instrument vendor has stopped supporting the instrument, you won't be able to get software updates. So you run the risk of the instrument not working with newer OS versions. At least having a documented over-the-wire interface means that (worst case) you can write a tool to get the data out and then use an open-source front end. http://minila.sourceforge.net/ http://xoscope.sourceforge.net/ * Small trace buffer: A 2K trace buffer (even with the delta-T compression) is not very much. Especially for debugging serial buses. This is in the class of the older (1990-ish) HP and Tek logic analyzers. I just got rid of an HP 1653B mixed-signal scope that had a 1K (I think) trace buffer, and I was often running into its limits. If there is smart triggering on (say) I2C transactions, you may not need as much of a trace buffer. * Trigger output? You may want to add a PC-based oscilloscope or use it with an external sampling scope. Does it have a trigger output so that you can use its logic triggering to trigger the other unit? It doesn't seem like it does (they say you can't cross-trigger if you have multiple units). Thanks, -- Ned Konz ned@bike-nomad.com http://bike-nomad.com