What logic analyzers to look at?

[ormandj]

Hi,

I'm in the market for a logic analyzer. I've been looking at the Saleae Logic Pro 16, but want to make sure I look at other offerings. I've tried searching, and found a few others such as the USBee, but they don't seem to be as polished/supported. What brands should I look at? I'd like 16 channels if possible. Thank you!

[Gyro]

I don't know where you're located but there's an original Saleae Logic 16 (not pro) for sale in the Buy/sell/wanted section at the moment.

https://www.eevblog.com/forum/buysellwanted/fs-saleae-logic-%28original-8%29-and-logic-16-%28original%29-us-buyer/

I have no connection and don't know how the price holds up...

[uncle_bob]

Hi,

I'm in the market for a logic analyzer. I've been looking at the Saleae Logic Pro 16, but want to make sure I look at other offerings. I've tried searching, and found a few others such as the USBee, but they don't seem to be as polished/supported. What brands should I look at? I'd like 16 channels if possible. Thank you!

Hi

This quickly spirals off into a bunch of "what do you need to do" / "how much can you afford to spend" sort of questions. There are cheaper gizmos that will at least capture logic signals at some frequency. There are more expensive gizmos (some MUCH more) that will run faster / jump higher / have more features. My main gripe about the Pro 16 is that they bumped the price up recently. It's a great little gizmo with good support. It's main competition are dirt cheap Chinese copies of their previous generation device.

The biggest discriminator on the USB gizmos is the software on the computer. This or that neat hardware feature is pretty useless if the software only runs on Windows 95 These companies tend to go into business with high hopes. They run for a bit (maybe many years) and then vanish. Often they are killed off by pirate copies. (Why buy the real one when the clone runs all the same software ...). Once the company is gone, software updates for newer OS releases are pretty much impossible. If there is a change in "driver signing", you have to pick an OS upgrade --OR-- your USB gizmo. 

More questions than answers ...

Bob

[plazma]

Also consider the Analog Discovery 2. There is an academic discount for it if you are a student.

[0xdeadbeef]

I still think Ikalogic Scanaplus is a very good choice if you don't intend to capture signals with more than ~12MHz permanent signal changes (sample rate is fixed at 100MHz and data is compressed, still USB2 bandwidth limits apply) or need things like a trigger output or a clock input. I think no other analyzer in this price range offers comparable trigger options (complex multi level, protocol trigger). Plus you can easily write your own decoders in Javascript or modify/extend the existing ones.

A new entry in my LA collection is a DSLogic Pro which has very good HW specs (up to 400MHz sampling, RLE, streaming below 10MHz, 16MSa capture buffer  above that, trigger output, clock input) and the Sigrok based software looks quite sleek. Plus everything is open source as far as I understand. The trigger system could need some rework though. Even though it offers 16 trigger levels and some parallel/serial options, it seems to lack import things as time constraints and the setup is about as messed up as with the existing GUIs for the Open Bench Logic Sniffer. My main concern though is that the protocol decoding is incredibly slow. Obviously Sigrok's Python decoder scripts go through the capture buffer sample by sample instead of transition by transition. It takes minutes to decode a few (like 5 or so) UART transmissions in a 128M buffer. The same thing takes a split second in ScanaStudio (the GUI for the ScanaPlus).

[BloodyCactus]

I got from ebay a LWLA1034 (32channel) which is supported + endorsed by sigrok and runs fine with PulseView (sigroks front end software)

http://sigrok.org/wiki/Sysclk_LWLA1034

dslogic... i kickstarted it, not impressed. I would not get one. they forked sigrok (which is fine) but did not bother to submit any patches back (which sucks imo but its all part of open source!). the unshielded wires they gave with it were very noisy to the point of useless. the newer versions ship with shielded ones which should be better. its basically the same as all the other chinese usb la's.

[alank2]

I'm the guy with the Logic 16 up for sale.  I'm on the fence about selling it because I really do love it.  I have had the Saleae original logic, Saleae Logic 16 (which I'm selling), Intronix LogicPort, and I just added a Saleae Logic Pro 16.

FWIW, I love the Saleae software and UI.  I can't say the Intronix is bad, but I prefer the Saleae, it is easier to use.  And it is open, I can write a custom protocol analyzer for it if I need to (like the HD44780 LCD interface one I wrote).

I was on the fence about how useful the analog would be in the Pro 16, but after 10 minutes of using it on a project, I am sold.  You don't have to get out your scope or clunky scope probes and you can turn on the analog for signals you want to see how they are behaving, and then turn them back off to save bandwidth/memory once you are happy that they are stable.

The Intronix LogicPort advantages are (1) you can set the logic threshold using 0.05V increments from -6V to +6V which is fantastic, (2) it can sample all of its inputs (34 of them!) at full speed (up to 500M), and (3) its software is stable and can run even on slower PC's.  Downsides are that it has a short buffer (2K) which means that you must fiddle around with trigger settings to get the data you want, the UI is not as polished, doesn't have as many analyzers, and the software isn't updated as often.

The Saleae advantages are that you don't have to fuss with trigger settings, there is no sample buffer so you can capture as much as want (given your memory) and look through it at your leisure.  I can't say enough positive things about the Saleae team, they are always helpful and just all around great guys to deal with.  They have a 6 month trial period and a 3 year warranty so you can't go wrong there either.

The Saleae original Logic 16 is USB2 and can capture 100M for 3 channels, 50M for 6 channels, 40M for 7 channels, 32M for 9 channels, 25M for 12 channels, or 16M for all 16 channels.

The Saleae Pro 16 is USB3 (or USB2 but it is 7 times slower on USB2, speeds like the original Logic 16) and can capture 500M for 4 channels, or 100M for all 16 channels.  The analog will use considerable bandwidth if enabled and slow down the sample speed for digital as well.

Good luck!

[tggzzz]

You need to define the logic families you will probe (voltages, differential, etc ), the sampling rate, synchronisation with UUT clock signals, arm/trigger values and sequences, protocol decoding, number of samples, time resolution, frame decoding, etc.

You may find that, with a little imagination, you can use printf statements and oscilloscopes.

[nctnico]

I'd get an MSO with decoding and if necessary a real logic analyser from Tektronix (TLA700/7000 series) or from HP/Agilent (16000 series). An MSO will be useful for 99.9% of the logic analysis tasks and a real logic analyser can be used to crack the really tough problems.

[0xdeadbeef]

I got from ebay a LWLA1034 (32channel) which is supported + endorsed by sigrok and runs fine with PulseView (sigroks front end software)

dslogic... i kickstarted it, not impressed. I would not get one. they forked sigrok (which is fine) but did not bother to submit any patches back (which sucks imo but its all part of open source!). the unshielded wires they gave with it were very noisy to the point of useless. the newer versions ship with shielded ones which should be better. its basically the same as all the other chinese usb la's.

The DSLogic Pro sold now is an improved version and has shielded wired. No noise problems whatsoever from what I can tell. Also the input stage is improved (variable threshold between 0.1 and 5V in 0.1V steps).
As I said it looks like a solid piece of hardware with a usable software. Just the protocol decoders are so slow they are nearly unusable - but this seems to be a limitation that comes from the Sigrok PulseView decoder architecture.
The LWLA1034 you propose seems to be worse in any regard expect for more channels. It features only 256K samples per channel compared to 16M for the DSLogic. Also no input protection whatsosever (DSLogic: -30V to +30V), no selectable thresholds and the wires don't look shielded either. I also understand the trigger system is very basic. Just one trigger level  based on either edge or level for all the channels. So for only 20€ more, the DSLogic Pro seems like quite a bargain.

[Muxr]

Can't go wrong with a Saleae. When it comes to USB instruments companies often screw it up. Saleae software is clean, provides the essentials and works great. It works, and it's really easy to use.

[ormandj]

Sounds like Saleae is the way to go for something well supported that will work with minimal fuss. I appreciate all of the suggestions, I've been looking through all the specification sheets and seems like this is the way to go.

[BloodyCactus]

The DSLogic Pro sold now is an improved version and has shielded wired. No noise problems whatsoever from what I can tell. Also the input stage is improved (variable threshold between 0.1 and 5V in 0.1V steps).
As I said it looks like a solid piece of hardware with a usable software. Just the protocol decoders are so slow they are nearly unusable - but this seems to be a limitation that comes from the Sigrok PulseView decoder architecture.
The LWLA1034 you propose seems to be worse in any regard expect for more channels. It features only 256K samples per channel compared to 16M for the DSLogic. Also no input protection whatsosever (DSLogic: -30V to +30V), no selectable thresholds and the wires don't look shielded either. I also understand the trigger system is very basic. Just one trigger level  based on either edge or level for all the channels. So for only 20€ more, the DSLogic Pro seems like quite a bargain.

nice, didnt know about the pro, if they fixed the issues, cool beans!

for the lwla1034, I only use it for spi/i2c stuff. (the model with lesser channels has issues). If I need more than 4 channels, I break out my big boy agilent 1670G with 130 channels and state comparison and real triggers.

[pallisi]

Hallo all,

I am searching for a logic analyzer these days. I would like some advice about this purchase. My main use would be to decode SPI, I2C, UART and CAN protocols from low end MCU (arduino, MSP430, C2000). My main concern is to the decoding function of the analyzer's software. I want it to be fast.

So far I am between: Saleae, DSLogic, ScanQuad. I find the Saleae software more user-friendly and fast, but the devices seems to be  overpriced. The DSlogic is powerful but I do not even like the interface of the DSview. The ScanQuad seem ok in both of price and device. I think that the Saleae has the best support.

Which of those analyzer would you choose according to my specs? Any advice would be helpful.

[0xdeadbeef]

Regarding DSLogic vs. ScanaQuad (I have both, don't ask): keep in mind that the ScanaQuad doesn't support RLE compression while the DSLogic does. Besides the DSLogic supports streaming for lower sample frequencies (forgot the exact number, I think it's like <= 10MSa/s). So compared to the DSLogic, the ScanaQuad can only capture quite a small period. And it has only four channels and doesn't have a trigger output. Well, I asked about this in the Ikalogic forum a while ago and there was a cryptic statement that it will be possible in the future by additional hardware, but at the moment, there is no trigger output.
Then again, ScanaStudio has much better trigger possibilities than what DSLogic provides (there are 16 trigger levels, but not time contraints) and the protocol decoding is MUCH faster. In a comparison of ScanaPlus (yeah, have that as well) vs. DSLogic I compared a UART message sent every 100ms over a second with 100MSa in each case. ScanaStudio decodes this more or less immediately while DSView (the DSLogic software) needs several minutes (!) for a few messages since it goes through the buffer sample by sample.
So if decoding speed is important to you, I can't recommend Sigrok based stuff like the DSLogic to you. Then again, the ScanaPlus is very limited (capture period and number of channels).
Of the five LA I own (plus some very expensive ones at work), I still like ScanaPlus the best. But at the moment, I find it hard to recommend it as there are major issues with the new software and the Ikalogic team was not very responsive in the last weeks. Still, with the old ScanaStudio (V2.3) and older FTDI drivers it works perfectly well and I kinda assume the issues will be fixed (e.g. they seem to have their own driver certified). But, yeah well, it's a bit frustrating right now.

[pallisi]

It seems that with the present limitation in hardware (ScanaQuad) or in software (DSlogic) the Saleae is a one way solution.
It seems that it justifies its price but it is still high for me.

Any other suggestion will be helpful.

[0xdeadbeef]

I understand that the Saleae analyzers have only very basic trigger capabilities (no trigger levels at all). Even though I was alleged of being paid by Ikalogic (which unfortunately is not the case) for repeating that,  but I still find that the ScanaPlus is a pretty good solution for the price. As stated before, there are currently somewhat severe issues with the latest V2.4 beta software though (only with ScanaPlus, ScanaQuad works fine) but I used V2.3 very intensively lately and this version is very mature and stable. The only major thing it lacks is the protocol triggering. And I'm still optimistic that the guys at Ikalogic will fix that V2.4 beta issues soon.

[alank2]

With the Saleae, the triggering works like this:  You can set a channel for positive edge, negative edge, positive pulse, or negative pulse.  You can set the min/max width of the pulse.  For other channels you can set whether they must be low, high, or don't care.  I also discovered there is a glitch filter too that you can enable for each channel.

I barely use the trigger settings at all - that is the nature of hitting capture and recording all you want and then looking through it to find what you want.  The one time I do use it is if I want to keep the timeline consistent.  If I am zoomed into an event occurring 3 milliseconds from startup that might be present or not, I can trigger on reset and my view/zoom will stay the same so the event will either be present or not or show the change I was hoping it would.

[pallisi]

Hi all! At last I bought the scanaquad SQ100. The device was delivered immediately. The software is snappy and does a very good job. I only had a problem with the windows 7 driver, but the tech support of the ikalogic helped me. For now I only had limited time to test it. For SPI and UART protocols works just fine and the decoder is fast.

[diyaudio]

I own a sale logic 8 (clone) works well, however after watching mike`s videos reverse engineering an Apple IPOD LCD it became very clear how important a MSO real-time logic analyser is. however if cost is an issue, we have no choice but to use what we can afford.