USB Logic Analyzer Recommendation

[GreyGnome]

I did a search and came up with a goose egg! ...Eeep... dare I ask?

Do you have a recommendation for a USB-based logic analyzer? I need something portable that I can use to work on my Arduino projects, which are also portable (battery powered). I have felt the need to monitor the outputs of ATmega328 pins, including some fairly short (62.5 ns) pulses, so I'm concerned about having enough bandwidth to accurately grab such things.

I have not used one before, so I don't have the experience to dodge the units that are missing something essential.

Preferably supported by Linux-based software, but I'm not against firing up Wine or even VirtualBox.

Thanks.

[masterx81]

 I have recently bought an dslogic u2 basic. It's a nice unit and have some memory  to use as buffer. And searching a little bit can be upgraded to the plus version (or can buy directly the plus version). Never had a logic analyzer, but in no time i was decoding spi data. The sw is nice. The configurable trigger level is really useful. As this is my first one i not know how the other can be, but this seem a good one. For the speed, 400mhz buffered sample rate on (if i remember well) 4 channels. 100mhz via usb. With more channel goes slower (with all 16ch 20mhz via usb and 100mhz buffered). Used on windows, not know if it run on linix

[0culus]

Saleae is a top brand in this space. Have you looked at them?

[Wimberleytech]

Saleae is a top brand in this space. Have you looked at them?

I second Saleae.  I have one and it saved my bacon once!

[angrybird]

I have several Saleae Logic Pro 16's and I love them to the point where they have lived in some longer-term projects during the entire development.  The ability to capture both analog and digital in such a small package with continuous streaming through USB 3.0 is priceless.

I also have Digilent's digital discovery which is nice as well, albeit limited for my common uses due to its memory capture depth, but it is much (!) cheaper than the Logic Pro 16.

It should come down to what you require as far as memory capture depth, whether or not you need analog + digital in parallel, and what protocol decode options you need.  For instance, I have some of these old ZeroPlus units that seem to have every protocol I can think of, but their capture depth is limited to 2MB per channel.

It is well worth it to ponder what your requirements are before you purchase.  I generally always go for as much functionality as I can afford, which usually pays off later, or at least that's what I tell the wife 

[Tony_G]

Have Saleae added the ability to search the message logs yet? I haven't used my 1st gen unit for a while but that was the number on thing that annoyed me - I wanted to find a specific set of bytes on the I2C/SPI decodes and you couldn't look for a complex pattern.

That said, mine is a great unit and I think unbeatable for the price and quality (at least the gen 1 units).

TonyG

[kripton2035]

along with a >100MHz analyzer (clone eventually)

[Noy]

DSlogic is now providing also USB3 Devices
https://www.dreamsourcelab.com/shop/logic-analyzer/dslogic-u3pro16/

But i already own a dsLogic Plus... Would only be interesting for me if i can decode Highspeed USB but thats not supported yet. Only Full/Low Speed and for that the Plus is enough...

[0xdeadbeef]

Letting aside that even 1Ghz sample rate doesn't seem nearly enough to properly sample a 480Mbit/s signal: at some point, the sample rate isn't the problem any more but the probes' bandwidth, capacitance and inductance. I somewhat doubt that probing highspeed LVDS signals will work well with this kind of probes (even though they are shielded which specifically reduces the inductance loop if connected properly).
Anyway, the price increase just for USB3 is much too hefty. I always use the internal buffer (RLE) with my DSLogic(s) anyway as it was always sufficient for my needs.
This being said, it's nice that the people at DreamSourceLabs are still alive - there were actually also a very few SW updates in the last years. I still wished they would rework the GUI and implement a proper advanced trigger setup. Apart from that, the DSLogic (Plus) is what I use the most currently of all the logic analyzers I own.

[angrybird]

USB 2.0 testing typically consists of two parts: Protocol analysis, and compliance testing.  Compliance testing is done on a scope, protocol analysis done on an analyzer like the TotalPhase Beagle 480.

With this being said, it would certainly be possible to do decode with the beagle 480, but consider that this unit also has only a USB 2.0 interface, so if you are watching a continuous data transfer, you may run into some bandwidth issues here.  My experience is that the Beagle 480 is good enough for most development needs when designing a product and running into protocol issues.

I do have one complaint about it - It is a pass-through device, and actually has a noticeable affect on the USB 2.0 eye diagram.  So if you are already marginal and almost failing, you will be failing once you go through the beagle!

[colorado.rob]

For short pulses, you should consider using an oscilloscope with enough bandwidth. 62ns is easy even for cheap scopes, and many can do basic LA type work including protocol decoding.  For a general-purpose, USB-attached logic analyzer for Arduino projects, the cheap $10 USB logic analyzers found on eBay, along with Sigrok work great.  These are 24MHz LAs.  There are 100Msps LAs that cost around $50 if you want to spend the money, but for Arduino projects, its a bit of overkill.

What sort of 62.5ns (16MHz) signal are you trying to measure from an Arduino?  That's the clock speed of most Arduinos.

[GreyGnome]

For short pulses, you should consider using an oscilloscope with enough bandwidth. 62ns is easy even for cheap scopes, and many can do basic LA type work including protocol decoding.

What sort of 62.5ns (16MHz) signal are you trying to measure from an Arduino?  That's the clock speed of most Arduinos.

Thanks. I already have a Rigol 1052E. Now I'm looking for something with a little more sophistication regarding eg I2C and SPI protocol analysis.

Sometimes I like to pump out register values on a pin using some quick port twiddling for debugging. I also send quick pulses to flag events, using them to measure distances between sections of code, to tighten it up. I did a lot of this sort of thing when I wrote the EnableInterrupt library for the Arduino.

[GreyGnome]

Saleae is a top brand in this space. Have you looked at them?

Yes. They look interesting, although a little pricey. I'm trying to decide if the extra expense is worth it, vs. a $100 Sigrok-supported unit.

Do you know anything about Picoscope? If I'm looking at eg the Logic Pro 8 at $700, I notice that the Picoscope 2206B MSO has 2 analog + 16 digital channels, and its analog scope bandwidth is 50 MHz vs. 5 MHz for the Salae.

[strayelectron]

DSlogic is now providing also USB3 Devices
https://www.dreamsourcelab.com/shop/logic-analyzer/dslogic-u3pro16/

But i already own a dsLogic Plus... Would only be interesting for me if i can decode Highspeed USB but thats not supported yet. Only Full/Low Speed and for that the Plus is enough...

Have you used a saleae? If so, care to comment on which software you liked better, regardless of the specific model analyzer's capabilities?

[Gyro]

IIRC, you can download both software packages and run them in demo mode (you certainly can with the Saleae).

[0culus]

Saleae is a top brand in this space. Have you looked at them?

Yes. They look interesting, although a little pricey. I'm trying to decide if the extra expense is worth it, vs. a $100 Sigrok-supported unit.

Do you know anything about Picoscope? If I'm looking at eg the Logic Pro 8 at $700, I notice that the Picoscope 2206B MSO has 2 analog + 16 digital channels, and its analog scope bandwidth is 50 MHz vs. 5 MHz for the Salae.

I've only used them at work, but they are very very nice IMO. You'd have to decide what your budget can take. One point on Saleae's favor vs most vendors is their first party API and protocol analyzer SDK is fully open, so if you have some programming experience, there is a way forward to implement custom protocols and things that aren't supported out of the box. I have no experience with sigrok, but I presume since it's open source you ought to be able to do the same thing. I also don't have experience with picoscope, sorry.

https://support.saleae.com/saleae-api-and-sdk/protocol-analyzer-sdk

[egonotto]

Hello,

I think the Picoscope 2206B MSO is more versatile. For 62.5ns puls is 5MHz far too little. If you have a question about the Picoscope you can ask in the picotech forum https://www.picotech.com/support/

Best regards
egonotto

[cynric]

Mind if I hijack this thread?
I'm currently in a similar position as the OP and would like your input on choosing a USB logic analyzer.

My current project needs me to log a 4 wire SPI running with 60MHz. The actual data amount is not going to be much, but accesses will likely be spread out over some time (say 1-2 seconds). So I would ideally need the solution to be able to trigger on CS repeatedly. Either that or a device that can "stream" 4 channels at at least 200MSps continuously.

I've looked in detail at the Digilent digital discovery and the DSLogic Plus and the brandnew USB3 editions.
While the DDD seems to have promising hardware, I like that you can use it as a signal generator or for actual communication with the DUT. The software seems to suck and be pretty inflexible regarding the classic LA/protocol decoder part - sadly there is no Sigrok support for the DDD, not even planned.
DSView being based on Sigrok seems to be both expansive and intuitive, however the demo mode does not allow me to dig too deep into the DSLogic hardware capabilities, so I am not sure it that would work for me either..

The new DSLogic U3Pro16 seems to be doing all I want, however I do not really want to spend more than 200€ on this (taking customs of ~50-60€ to come on top of the U3Pro's 270€). Additionally this thing is so new that there seem to be no reports of it yet..

So I've got some questions for you guys: Does the DSLogic allow its RLE compression to be used in streaming too, so that maybe I can get my 200MSps from the Plus when the bus is mostly idle? Or maybe it supports repeated triggering while still retaining the data of the former instances? Maybe I am mistaken about Digilent's WaveForms and it better than it seems at first look? Or are there any other LAs that fit my bill (8+ channels, 200+MSps, Streaming or with a huge buffer, good sofware/Sigrok support, not too much over 200€)?

Thank you!

[GreyGnome]

Have you looked at the ASIX SIMGA2? They've got 32MB (== 256Mbit) of RAM onboard, and 198 Euros. You could check with their support staff about your other requirements.

Plus, they seem to have played well with sigrok- although the triggering is apparently non-functional at present.

[GreyGnome]

Right now the top pick in my list is the ASIX Sigma2 http://www.asix.net/dbg_sigma.htm . (Available in the US at https://microcontrollershop.com/product_info.php?products_id=1970&osCsid=5uu1adptl33g7m6rsa3sjh1kv3 ). Linux support is limited to WINE, but I can live with that for now.

DSlogic is attractive, but they have been poor players with the sigrok folks, and I can't support that.

From my chat in their IRC channel: "(one of the sigrok developers is) still very much hostile towards them because of their continued acting in bad faith... For example, they initially shipped a firmware for the DSLogic based on our fx2lafw (without crediting us). They now have a new firmware that they refuse to open source, meaning we cannot verify whether they still use parts of fx2lafw or not. Also, they love merging tons of on commits into one huuuuge commit that they then put on the public repo so that everything is entangled and no one can take over anything. Alas, people love them because it's cheap and they keep syncing with the libsigrokdecode repo to benefit from our protocol decoder work..."

[PKTKS]

Another vote for Saleae + Sigrok

Doing the math this combination allows you
to decode so much stuff using sigrok .. which
makes those very expensive "soft options"
hardware  looking like (expensive) crap

Unbeatable price effective combo
You may of course expend more..
I doubt the support and use would be better

Paul

[Gandalf_Sr]

I own a Salae Logic 8 and it's good.  The biggest issue I have is that it doesn't have the ability to send out signals.

I also own a Bus Pirate which can send and receive data in multiple bus standards and has neat macro stuff like scanning every address in an I2C range and telling you what responses it got - that has helped me realize that the devices on my bus weren't at the addresses I thought they were.  I must caution that the Bus Pirate is crude, buggy, the UI is a serial terminal like TeraTerm, and hard to find the instructions for. But it works and it's cheap.  I have a 3.6 and a 3.8 - I don't recommend buying the 4.0 as it seems to have been abandoned as a project but I own one and it works, sort of.

[0culus]

I own a Salae Logic 8 and it's good.  The biggest issue I have is that it doesn't have the ability to send out signals.

I also own a Bus Pirate which can send and receive data in multiple bus standards and has neat macro stuff like scanning every address in an I2C range and telling you what responses it got - that has helped me realize that the devices on my bus weren't at the addresses I thought they were.  I must caution that the Bus Pirate is crude, buggy, the UI is a serial terminal like TeraTerm, and hard to find the instructions for. But it works and it's cheap.  I have a 3.6 and a 3.8 - I don't recommend buying the 4.0 as it seems to have been abandoned as a project but I own one and it works, sort of.

The Xipiter Shikra is way better (based on personal experience borrowing one from a friend), unfortunately, they are out of stock for the foreseeable future.

[kahuna0k]

Have you checked DigiView (https://www.tech-tools.com/DV518-logic-analyzer.htm), I was some time ago looking for the same thing and those seem cheaper that Saleae and not worse. I ended up buying a DSLogic plus (to add to my Digital Discovery and many other super cheap LA) as $500 was hard to justify, but I know that I will end up buying it

[Gandalf_Sr]

Have you checked DigiView (https://www.tech-tools.com/DV518-logic-analyzer.htm), I was some time ago looking for the same thing and those seem cheaper that Saleae and not worse. I ended up buying a DSLogic plus (to add to my Digital Discovery and many other super cheap LA) as $500 was hard to justify, but I know that I will end up buying it

Hmmm, another $600 listen-only logic analyzer.  The Bus Pirate 3.6 is available for $30 on Amazon and can transmit and receive in 1-Wire, UART, I2C, SPI, raw 2-wire, raw 3-wire, HD44780 LCDs, and MIDI. With a firmware upgrade it can also do PC keyboard, DIO, and JTAG.

Does it have a slick interface? No. Does it get the job done? Yes.

YMMV