Logic Analyzer - why so expensive?

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Hey Freaks,

right now I'm at the start of my final semester project (I implement the USB Connection + GUI for a 'I compute the s**t out of you'-FPGA) and my boss who is designing the FPGA moaned about his "crappy" logic analyzer. The problem is the small memory, thus it can't record enough data. I experienced the same issue with several DSOs.

Problem is that ... those devices with mucho RAM cost the same like a small car, but who am I telling this? Well ... gosh why is this so? If you calculate todays memory prizes down to "$ per Bit" we pretty much get money back.

Plus: I'm eager to lean FPGA programming since about a year. Wouldn't this be a nice starter project? (keep in mind that I learn how to do USB streaming and GUI right now) I'm thinking about 32 Channels scanning a bus which runs with ... maybe 100 MHz? (whew, OK that would produce 400 MB raw data per second(!) )

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I would guess that its considered "premium" and pricing "what the market will tolerate".

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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The $99 Xilinx Spartan 3 board from Digilent can be used with the free Sump.org software:

http://www.sump.org/projects/analyzer/

Leon Heller G1HSM

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leon_heller wrote:
The $99 Xilinx Spartan 3 board from Digilent can be used with the free Sump.org software:

http://www.sump.org/projects/analyzer/


Leon - have you used this before? Just curious. The software looks pretty primitive, but perhaps it is enough?

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I've got one of the Digilent boards, with an S3-400 on it, but I've never actually tried it myself. I did try running the software on my XP system, but had some problems with it; I forget what they were.

XMOS chips can capture 100 MHz events, and will do high-speed USB in software. I'd like to try one of those, with some external RAM.

Leon Heller G1HSM

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It's not high end, but it's a Spartan based logic analyzer using the Sump client:

Dangerous Prototypes' Openbench Logic Sniffer

Cheers,

Tom

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Quote:

The $99 Xilinx Spartan 3 board from Digilent can be used

Please note that that board is 3.3 Volts, so if you plan to attach eg a 5 Volt system you need to add level conversion. The Openbench board claims to have this built in.

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The mentioned openbench logic analyzer kit for $45 is becoming available. I've ordered one and they are supposed to start shipping these days. The kit is designed as logic analyzer and has 16 buffered and 5V tolerant channels (32 channels total, but the other 16 only 3.3V).

See also: https://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=90638

Markus

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Nephazz wrote:
my boss who is designing the FPGA moaned about his "crappy" logic analyzer. The problem is the small memory, thus it can't record enough data. I experienced the same issue with several DSOs.

What kind of logic analyzer it is? USB, built-in to some oscilloscope, or standalone logic analyzer?

In general I have the same experience, either there is too little memory or sampling is too slow.

Nephazz wrote:

Problem is that ... those devices with mucho RAM cost the same like a small car, but who am I telling this? Well ... gosh why is this so? If you calculate todays memory prizes down to "$ per Bit" we pretty much get money back.

What kind of memory? Big difference between fast enough SRAM and too slow DRAM.

Nephazz wrote:

Plus: I'm eager to lean FPGA programming since about a year. Wouldn't this be a nice starter project? (keep in mind that I learn how to do USB streaming and GUI right now) I'm thinking about 32 Channels scanning a bus which runs with ... maybe 100 MHz? (whew, OK that would produce 400 MB raw data per second(!) )

Well that is one thing - You can't stream 400MB/sec through USB. You need to have enough memory to store what you need to see, and transfer it slowly to PC. That is not real-time. The other option is that you stream real-time to PC, but then the sampling rate is slow.

I have two different USB logic analyzers. I use the other to capture short high speed events up to 32 channels (Intronix LogicPort), as it can work up to 500MHz and has 1-2 kilobits of buffer per channel. The other I use is for longer slow speed events up to 8 channels (Saleae Logic), as it can reliably work at 4MHz sampling speed for tens of seconds on my laptop. Shorter few second captures can work up to 8MHz or so, and propably 24MHz sampling speed needs dedicated USB controller and blazing fast PC.

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I remember once I needed to analyze about 10 seconds of fairly high speed traffic and ended up paying the best part of £800/week for a couple of weeks to hire a £20,000 Agilent (well it was HP then) "deep buffer" analyzer.

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I think of getting one from this company. http://www.zeroplus.com.tw/logic...
Their basic model is around €120. (www.eleshop.nl)

Does anyone have experience with this thing?

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Slowly recalling an earlier thread on this subject, and a search reveals it: https://www.avrfreaks.net/index.p...

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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One of the reasons why "real" analyzers cost lots of money is that they pay attention to input circuitry. That circuitry has to be FAST and it has to be tolerant of a wide voltage range and it is replicated MANY times. That makes cost. Or, at least part of it.

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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Thanks for all the answers. Looks like I underestimated high-end LA's. I did a small research thinking "how expansive could fast RAM be?" and BAMM cypress hits my young a*** with like $500 for 72 MB :D