Anyone using a logic analyser ?

[Spectric]

I am currently looking at logic analysers, the days of the big bulky HP and tektronix beast are now in the past, very high quality machines with plenty of features and channels but now a tad slow for todays systems and the options now seem to be so different to what they were so is anyone using a logic analyser for any projects and if so what are you using and your views / opinions would be appreciated.

 

[John Brown]

I think it all depends on what you want to do. Maximum sampling rate and number of channels would be a good starting point.

 

[Spectric]

For me it is a step change because with my old tektronix which was a standalone unit with 64 channels, these were the days where the systems I worked on had external address / Data buses and we had to map hardware using 74 series logic chips for address decoding but now I only need 16 channels for digital signals and protocol decoding for CAN & SPI. Sampling 4 channels at 100Mhz will be ok for the 20 Mhz signals and the ability to use external clocking.

The market seems to be flooded with asian products, many being either copies or copies of copies and with price ranges starting at £12 which seems amazing, almost to good to be true when bench versions used to set you back a few grand. I suppose a case of technology moving forward, getting more into a single micro or FPGA and overall size just shrinking.

I have found several that initially look reasonable but reviews state things like you cannot save the setup which is not good if you have to repeat previous work, also some of the software looks like it has not been updated for some while and some do not even mention windows 7. The ones I haved taken more interest in are

The LA2016 from Kingst
Picoscope
Intronix
Lapc logic cube

These being USB options for a PC I have also looked at mixed signal scopes as another option but they are more expensive.

What I am looking for is someone using a product that they would recomend on the grounds of it being user freindly, stable and has a feel of quality just to make sense of the confusion out there.

 

[paulrbarnard]

I have a picoscope oscilloscope and it is actually pretty good. As you say the SW tends to stagnate but it was fully featured when it was created and still does the same today.

I’ve not used their logic analyser though.

 

[Sideways]

I've no recent experience to answer the question but I'd offer the following in case you haven't explored all of them already.
Mixed signal scopes from Rigol and Siglent with their logic analyser options
USB connected logic analysers from Saleae - their software is published for win 8,10,11, OS-X and Ubuntu linux (free to download and try it).
Either of these will cost you £800 to £1300. One option gives you a nice digital scope too, the other a better logic analyser.
Have a look and see what the members are saying over on Dave Jones' EEV Blog.

 

[Spectric]

USB connected logic analysers from Saleae

This is the minefield area, the Saleae was the original and still commands a high price but it is also the basis for many clones all using the same Xilinx Spartan 6 FPGA with the Cyprus FX2 bus adaptor which by the way actually has an 8051 processor core built in !

It looks like the hardware just gathers the data and the software provides the GUI and is why software like Sigrok works on many hardware devices including Saleae and then we have the Chinese company Dreamsourcelab with their own version of software hosted on Github but without the ability to save a setup which seems rather daft, my old Tectronix from the eighties could save multiple setups.

I will look at that blog @Sideways , blogs are not something I look at often but maybe they can shed the light.

 

[John Brown]

Why not buy one of the £8 ones and see how you get on? They'll decode async serial, SPI, I2C etc. Won't decode USB, though.
I have a cheap clone version somewhere, found it fairly useful, but pretty much retired now.

 

[John Brown]

By the way, I believe Xilinx supplied the original FPGA code, so no great qualms about buying a clone.

 

[Spectric]

Well that blog from Dave had some good info on MSO's and highlighted some pro's & cons which I had not considered. The one of more importance is that the logic analyser in a low to midrange MSO does not use any data compression so you need to buy the more expensive high end which comes with many features you don't require and captures everything so filling up memory very fast unlike the logic analyser which only captures changing data and compresses the rest in between so using less memory.

From what I have been seeing recently there is a definate worrying trend that stands out which is the amount of information that is many years old, there is less and less new stuff and updates which suggest a falling interest in electronic's and this probably stems from the low numbers of people who now work in this sector.

 

[nickds1]

Analog Discovery 3

I use it all the time. Lovely little thing but a serious bit of kit which does just so much in a tiny package. I had an AD2 for years and have just upgraded. Digilent, who make it, have a long pedigree with this sort of kit and they're now owned by National Instrument so will be around for the long haul. The design for the AD2 was public - they provided a full AD2 h/w design manual, but not for the AD3 unfortunately - the AD2 was beautifully engineered, as is the AD3.

Lots of add-ons for it too. Properly supported with regular updates to both the host application and the AD - it's the host s/w that updates the AD - communication is over USB3 with a C-type connector.

Used to do a lot of long haul flights (one every couple of weeks) lasting 7+ hours each and used the time for quiet & productive s/w development using just an AD2, my laptop and a TI Launchpad... (*)


(") Always told the crew & my seat neighbors (if any) in advance what I was up to in case anyone got jittery about wires and the blinking LEDs on the bootloader etc.

 

[paulrbarnard]

Analog Discovery 3

I use it all the time. Lovely little thing but a serious bit of kit which does just so much in a tiny package. I had an AD2 for years and have just upgraded. Digilent, who make it, have a long pedigree with this sort of kit and they're now owned by National Instrument so will be around for the long haul. The design for the AD2 was public - they provided a full AD2 h/w design manual, but not for the AD3 unfortunately - the AD2 was beautifully engineered, as is the AD3.

Lots of add-ons for it too. Properly supported with regular updates to both the host application and the AD - it's the host s/w that updates the AD - communication is over USB3 with a C-type connector.

Used to do a lot of long haul flights (one every couple of weeks) lasting 7+ hours each and used the time for quiet & productive s/w development using just an AD2, my laptop and a TI Launchpad... (*)


(") Always told the crew & my seat neighbors (if any) in advance what I was up to in case anyone got jittery about wires and the blinking LEDs on the bootloader etc.

Your braver than me I often write software but never taken a HW target with me on a flight.

 

[Spectric]

have a long pedigree with this sort of kit and they're now owned by National Instrument

That sounds good and will take a look as having used Labview in the past and the associated hardware for instrumentation and control it is a good start. The Labview gui was really great and usable so NI have a good track record.

The AD3 is a lot more than just a logic analyser, it is also a waveform generator but already have these as standalone instruments and looks like a potential choice so will download and take a look at the waveforms software.

@nickds1 do you have any issues with it, not yet read the full specs does it provide streaming and record modes as well as data compression ?

 

[nickds1]

@nickds1 do you have any issues with it, not yet read the full specs does it provide streaming and record modes as well as data compression ?

The client is normally the free WaveForms app which runs on both Windows & Linux. I've not tried using it with LabView as I find WaveForms more than adequate for my needs. Hardware silo depth is 32k for each of the 16 channels but you can record millions of samples in WaveForms and then wind through (or export to CSV etc.) as necessary. Again, it may do data compression on the link but I'm not aware of it as USB-C more than caters for any bandwidth I need - I've never noticed it throttling.

And, no, neither the AD2 or AD3 have missed a beat - very solid - nicely made, which helps as my AD2 went all over the world and into some pretty hostile environments (deserts etc.) and never complained.

One good tip - get multiple flylead sets (they're quite cheap)... WaveForms saves all the pin designations etc. in a "project". One thing I've found very useful is to have a set of flyleads for each project and leave them connected to the project board. To switch to a new board, just unplug the AD from the board you were using, open the appropriate new project file in WaveForms (which re-defines all the pins) and then plug the AD into the new set of flyleads - saves ages in frigging around rewiring the tools as you move between projects.

Also worth mentioning is that support is excellent. There are peer-to-peer fora, e.g. Digilent Forum, as well as Wikis etc. See Support

 

[MikeJhn]

I married my logic analyser, but as the first post its getting a bit slow with age.

 

[Spectric]

Well having spent to much time not making saw dust I have narrowed the options down, thanks @nickds1 for pointing out the Digilent AD3 and @Sideways for that blog as that Dave guy has done a video on the AD3. Having tried various demo software from different vendors I must say none of it really jumped out but then I am more used to having benchtop equipment, so discounted Sigrok's Pulse view and then the Chinese version of it called DSview from Dream labs which I thought was much better than pulse view but still felt like a beta version. Saleae was good, much better interface and some solid looking devices but at more of a premium price. What I liked about the AD3 as shown in a video by the Quantizer, yes the Z gives him away as being American was the AD3's ability to not only to input digital signals but to output a protocol like SPI or I2C and therefore interogate a device or module with that interface which can make coding a microcontroller easier. So it looks like I will be going for the AD3 and BNC interface board once I find a stockist with stock.

Having not been so involved with the test equipment market for some time, I have now realised it has gone in the same direction as a lot of woodworking machinery in that there is so much asian imports and clones of this or that and they seem to dominate the lower sectors.