Looking for low cost usb logic analyzer with real time view - Page 1
Forum section: electronics / testgear

author: grips03
author_rank: Contributor
timestamp: February 13, 2016, 11:25:06 am
content: Looking for a low cost usb logic analyzer with real time view. I bought Saleae, but it does not provide real time view.

author: Karel
author_rank: Super Contributor
timestamp: February 13, 2016, 12:08:17 pm
content: Quote from: grips03 on February 13, 2016, 11:25:06 amIt doesn't exist. It's impossible to transport, process and display 500MByte/sec. realtime on a pc via USB.

author: grips03
author_rank: Contributor
timestamp: February 13, 2016, 12:12:14 pm
content: I noticed Analog Discovery has 2 port digital DC voltage meter. Any device like this with 8 channels?

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 13, 2016, 12:23:46 pm
content: The software for my (patched) ZeroPlus Logic Cube LAP-C(16032) has a "repetitive run" feature which automatically captures and displays the result periodically.I was too lazy to connect my Logic Cube as it rests in a drawer since I bought an IkaLogic ScanaPlus some years ago, but in demo mode, it updates the screen about every second.There a certain scenarios where this is somewhat helpful, but it's of course very limited.

author: grips03
author_rank: Contributor
timestamp: February 13, 2016, 12:59:46 pm
content: For my use case sampling about 100 times per second would be fine.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 13, 2016, 01:06:57 pm
content: Well, sample rate and display rate are not quite the same. I'd be surprised if there was any USB2 based solution that can display more than a few Hz with very limited sample buffer.BTW: does your PC's display allow for more than 60Hz at all?

author: grips03
author_rank: Contributor
timestamp: February 13, 2016, 01:12:15 pm
content: display rate of 60 would be fine

author: grips03
author_rank: Contributor
timestamp: February 13, 2016, 01:19:53 pm
content: I've not use logic analyzers in the past, however I was thinking they would sample at some rate and display whatever it could in real time. Then if stopped would provide full details.If the sample rate had to adjusted to 50/s or 60p/s to match the display rate I guess that would be fine too.

author: forrestc
author_rank: Unknown
timestamp: February 13, 2016, 01:37:31 pm
content: Quote from: grips03 on February 13, 2016, 11:25:06 amI agree, it doesn't exist, at least I haven't found it. That's part of the reason why I purchased the logic analyzer add-on when I recently bought a higher-end scope.Just curious, what are you decoding/looking at?My personal quest is less for a logic analyzer and more for a real-time protocol decoder. I regularly need to watch the traffic on some serial or parallel bus or another, and it's extremely hard to do so without high-end specialized tools. I'd love something which could attach to a bus and decode and capture the traffic on it in a streaming fashion without losing any data.

author: han
author_rank: Frequent Contributor
timestamp: February 13, 2016, 01:37:59 pm
content: Maybe you can describe why you need real time one.Perhaps you need DAQ (data acquisition) not Logic Analyzer.

author: han
author_rank: Frequent Contributor
timestamp: February 13, 2016, 01:39:35 pm
content: If Protocol analyzer you need, tryhttp://realterm.sourceforge.net/

author: forrestc
author_rank: Unknown
timestamp: February 13, 2016, 01:48:32 pm
content: Quote from: han on February 13, 2016, 01:39:35 pmYeah, I use realterm when I'm dealing with something serial. The problem is that the I2c/SPI support is more of a 'host adapter' support and not useful for troubleshooting a protocol issue say between a microcontroller and flash when using SPI. I also do a lot of 9 bit serial which is simply not supported as well.I'll probably end up just buying one of the beagle I2c/SPI protocol analyzers :http://www.totalphase.com/products/beagle-i2cspi/I already have a USB one and it works great for reverse engineering the USB protocols on not-well-documented devices I want to drive from a microcontroller.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 13, 2016, 01:57:34 pm
content: I still don't get why you'd need live view for this. I did SPI, I2C, SENT, LIN, CAN and UART analysis with my Ikalogic ScanaPlus and in the cases where I was concerned about the physical signal or a live view, I connected a scope in parallel.

author: grips03
author_rank: Contributor
timestamp: February 13, 2016, 02:40:21 pm
content: I'm basically trying to use a LA as a multi-port digital voltmeter (0-5v DC)

author: forrestc
author_rank: Unknown
timestamp: February 13, 2016, 04:34:46 pm
content: Quote from: grips03 on February 13, 2016, 02:40:21 pmIt really sounds like you're just trying to see the status of the signal lines in real time? Are these slow-changing signals?I think we're all a bit confused as to what you're trying to accomplish. Maybe give an application example. I.E. "I have a X and I'd like to be able to tell when...." or something like that...Most of the time a logic analyzer is designed to show you signals which are way too fast to even observe in real time. For example, the communication on a typical SPI bus is in the millions of bits per second range. The USB logic analyzer will record a certain amount of time, then stop recording and display what it recorded.

author: uncle_bob
author_rank: Unknown
timestamp: February 13, 2016, 04:49:58 pm
content: Quote from: grips03 on February 13, 2016, 02:40:21 pmHiOk, don't go for a logic analyzer if you need a multi channel DVM. You will be paying a lot of money for things you don't need. You also will have compromised functionality on the part that you do need.The next question becomes:How many ports do you need to sample?Do they need to be simultaneously sampled?Do you need a complete set of data (all inputs) 50 to 60 times a second?How accurate do you need the voltage to be? Is 8 bits good enough or do you need 24 bits?Take the number of ports x the number of sets per second and that gives you readings per second. IF it's serial (not simultaneous) the task is to find a mux and an ADC that will meet your needs. Multiply that times the number of bits and you have a number that will or will not fit on a USB data stream on a version 1, 2, 3, or 3.1 connection.If it needs to be simultaneous, you need a system with an ADC per channel. That's a different set of things to chase after and a bit different set of constraints.Lots of possibilities....Bob

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 13, 2016, 05:28:05 pm
content: Quote from: grips03 on February 13, 2016, 02:40:21 pmBut you are aware that a logic analyzer is fully digital? The better ones allow you to set the hi/lo threshold, but that's it.It sounds more like you're looking for a multichannel AD capture solution. Maybe something like this?https://www.picotech.com/data-logger/picolog-1000-series/multi-channel-daqBut again, while the according software allows realtime display to some degree, the update rate in the software will be limited to some Hz.

author: lux
author_rank: Newbie
timestamp: February 15, 2016, 09:40:23 pm
content: Install sigrok with PulseView:http://sigrok.org/PulseView shows the trace live. I have tested it with a Saleae clone from ebay.

author: KL27x
author_rank: Super Contributor
timestamp: February 15, 2016, 10:26:01 pm
content: QuoteThe LA will register 0V or 5V, not 0-5V. Maybe you want a really cheap USB oscilloscope.Or if realtime 0v/5V is what you really want to see, you could take your logic analyzer and breakout the inputs to add a logic probe to the channels. (I built an 8 channel logic probe, into which my LA can plug into, for instance).A logic probe typically indicates the difference between hi-Z and fast switching, so you can at least differentiate hi, low, hi impedance, and high speed switching that is too fast to see. If you are already plugged into the computer, the Sigrok software sounds like it would fit the bill.

author: fake-name
author_rank: Regular Contributor
timestamp: February 15, 2016, 11:22:20 pm
content: I'm not too sure why you think the Salele logic can't do this.The bundled Saleae logic *application* can't do this, but the actual saleae logic hardware is completely capable. I've written streaming protocol decoders for it in the past, and they have a pretty decent API.

author: uncle_bob
author_rank: Unknown
timestamp: February 16, 2016, 01:04:55 am
content: Quote from: fake-name on February 15, 2016, 11:22:20 pmHiProbably a good idea to let us know who you are addressing the comment to....Bob (the often ambiguous to the extreme).

author: leftek
author_rank: Regular Contributor
timestamp: February 18, 2016, 02:37:57 pm
content: A very good choice is SIGMA2 from ASIX. Designed and made in Czech (not China) and is high quality. Have competitive specs, you can see inwww.asix.net.It is not toy. Its far better choice compared Ikalogic.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 18, 2016, 06:50:22 pm
content: Quote from: leftek on February 18, 2016, 02:37:57 pmYou must be joking.The software looks like from the nineties, no streaming mode, there are three (!) free decoders without possibility to write your own and no protocol trigger.Regarding the HW, the DsLogic Pro has much better than the Sigma2 specs in almost any regards at half the price. Hell, this thing doesn't even have any kind of input protection.I actually don't see any reason why I would trade in either my ScanaPlus for my DSLogic Pro for this. Where actually I will most probably never really use the DSLogic unless I need more than 9ch or higher clock signals than 10MHz.And how should you take a company seriously that lists feature like this in the 21st century?Waveforms can be saved and loaded to a computer hard disc.Waveforms can be exported to a text file for further processing.Waveforms can be printed on a printer.

author: leftek
author_rank: Regular Contributor
timestamp: February 19, 2016, 11:50:20 am
content: Quote from: 0xdeadbeef on February 18, 2016, 06:50:22 pmA very good choice is SIGMA2 from ASIX. Designed and made in Czech (not China) and is high quality. Have competitive specs, you can see inwww.asix.net.It is not toy. Its far better choice compared Ikalogic.Quote from: 0xdeadbeef on February 18, 2016, 06:50:22 pmYes, and i think that YOU don't see not any reason to change YOUR ScanaPlus. Is the BEST.Quote from: 0xdeadbeef on February 18, 2016, 06:50:22 pmIf there are your criteria .......

author: plazma
author_rank: Frequent Contributor
timestamp: February 19, 2016, 12:30:33 pm
content: Analog Discovery seem to support live view for the logic analyzer:https://youtu.be/Aymumu3mYl8?t=828

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 19, 2016, 04:59:52 pm
content: Quote from: leftek on February 19, 2016, 11:50:20 amThat is a very unique way of arguing. Just repeat everything over and over again until everybody is so annoyed they go away!?Quote from: 0xdeadbeef on February 18, 2016, 06:50:22 pmI own at least four logic analyzers. Plus I have a few more at my desk at work - including one the size (and noise level) of a microwave oven.And while there are limitations and issues with the ScanaPlus of course, it's the LA that I use the most at work and at home.I'd exchange it for something better of course but this happened yet. E.g. the DSLogic Pro has superior HW but without improvement on the trigger system and the decoder speed, I'll only use it for specific tasks.Quote from: 0xdeadbeef on February 18, 2016, 06:50:22 pmAgain, I'm not sure you really got the argument. But an unprofessional web site hints towards unprofessional attitude. And there are more clues like offering a LA for a professional environment that lacks any kind of input protection. That's simply a no-go.

author: leftek
author_rank: Regular Contributor
timestamp: February 19, 2016, 06:24:22 pm
content: Quote from: 0xdeadbeef on February 19, 2016, 04:59:52 pmI am a simply user, not seller as you...

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 19, 2016, 07:35:45 pm
content: Quote from: leftek on February 19, 2016, 06:24:22 pmWow and I just thought your way of arguing couldn't get worse. So instead of bringing up anything at least barely resembling an argument you insinuate commercial interest now?While I'm still not sure your understanding of English is sufficient to understand the irony, I'd suggest you'd read your own utterances regarding that SIGMA2 thing.Maybe you'll notice they sound much more like an advertisement than anything I ever wrote regarding any of the devices I ever owned.

author: leftek
author_rank: Regular Contributor
timestamp: February 20, 2016, 07:33:14 am
content: First i have write in this thread, to suggest an other device. There is not only the Ikalogic.I see that in all your messages you are manic with Ikalogic.This explains why all the rest are worse for you.Anyone reading your messages on all threads for "usb logic analyzers", easily understand that your aim is to underestimate anything else from Ikalogic. Maybe you sell it!That's why i do not care your opinion. Its not objectively. Unfortunately i do not have any more time to spend for you. You are able to continue your advertising promotion free of my interrupt.

author: pascal_sweden
author_rank: Super Contributor
timestamp: February 20, 2016, 01:00:17 pm
content: I think the best summary about Ikalogic products and the company itself is the following:Logic Analyzers for bricoleurs, made by bricoleursIf you don't speak french, this can help:https://en.wiktionary.org/wiki/bricoleur

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 20, 2016, 01:13:25 pm
content: Quote from: leftek on February 20, 2016, 07:33:14 amIf you had better understanding of the English language or simple counting you could see that I didn't even mention the ScanaPlus in my first two replies in this thread. In other threads, I also mentioned bugs and issues with the ScanaPlus and the according software. It's just that with all the Logic Analyzers I tried (and I tried a lot), I personally like the ScanaPlus the most at this moment. Some years ago I said the same about the Open Bench Logic Sniffer in comparison to my Zeroplus LAP-C. I don't see why this makes my opinion less valuable than that of a kid recommending a Saleae clone or some unknown brand without proper input protection.