Looking for a new logic analyser...

[Mark Durham]

My trusty LogicPort 32 channel LA is starting to become a pain as it doesn't seem to work or be detected under Win11. So after 15 years or so, it's time to look for an alternative in the sub 500 GBP price range.

I'm looking for a 32 channel device that can sample at 50MHz - no need to go faster than that - for my 68000 adventures. I looked at the Kingst LA5032 (at around 300 GBP).

I also came across a 24-channel design on github by Agustín Gimenez Bernad that looked interesting in the fact that it appears possible to daisychain a second board in to increase the channels to 48 (or a 3rd board to get 72 channels) and uses a Raspberry Pi Pico. It's also pretty cheap at around 30 GBP per board but I think it's got quite a small capture buffer. But you get what you pay for.

I don't have a lot of desk space so I'm ideally looking for a USB based device rather than one of the trusty old HP or Tektronix hulks.

What do you guys use - other than the $5 8-ch 24MHz clones?

Mark.

Now, I know the Pi device isn't going to deliver the same performance as one of the Saleae devices 

[Ed Silky]

I have the Kingst LA5016. I often wish that I had 24 or 32 channels, as 16 doesn't allow me to see the data and address and control. Other than wanting more channels, the only thing that I wish it had is the ability to use a combination of signals as the trigger. I often need (want) that, so I made a small board that has a PAL, some input pins, and a trigger out, that I can use to trigger. With that small attachment I think it works really well.

-Ed

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[Mark Durham]

Thanks Ed. When you say "combination of signals as the trigger" are you saying that it can only be triggered on a single signal, say, a /WR signal but not a /WR to a specific address. I guess in Z80 speak, could it trigger on a write to a specific 8-bit IO address - so a high to low transition on /WR when A0..A7 are set to address 0x10?

The LA5032 has been in my sights for a while so is a possible contender.

Mark. 

[Ed Silky]

Hi Mark, not that complex... Just, trigger on `/IORQ & /WR`. The Kingst can only trigger on a single signal (as far as I know anyway).

-Ed

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[Tadeusz Pycio]

As for affordable options, I was once thinking of buying the PX Logic USB3.0 32 CH; now there’s another product on the market that might be of interest: the FNIRSI DLA-32 Plus. Unfortunately, I don’t know anyone who uses these analysers, so I don’t know what they’re capable of. I’ve stuck with my LA2016, even though those 16 channels have long since ceased to be sufficient. I have built two analysers based on Agustín Gimenez Bernad’s design, but I haven’t tested them yet, although I can’t expect too much from them given their sampling rate, buffer size and transmission method. It's always good to have the feeling of having 48 channels if the need arises. ;)

[T Gerbic]

Sometimes I hear bragging that one LA or another has huge capture buffers compared to the old HP analyzers, and maybe some opensource ones.  I am generally not impressed. You may need a lot of buffer if you don't understand how to setup triggers.  If you are looking for something specific and set up the trigger(s) for that event, you may only need a K or two of memory depth to see what is happening. As with any test equipment, learn to use it and try to use all the functions the designers put into it.  

Sample rate is mostly important if you are looking for a race condition of needing to check the timing of a pulse.  Most of the time may be looking for data bytes or addresses where you don't need PS accuracy, or just looking to see if the processor switched some read or write signal to store a byte. To me good sample time can be important but only if you really need it. Think about what you will do with the LA.  If you are looking for some nanosecond or faster error, it may be better to look for the transition with an oscilloscope and zoom in to make fine measurements. Use the right tools for the job. 

One reason you may be worried about the transmission method is that you may be trying to capture way too much info for too much time, or you are capturing more channels than you actually need. To see the signals around a flip flop, you probably don't need 24 or 48 channels of capture. Maybe 8 bits of data, three on the FF and a couple of control signals. So maybe five to 15 is all that is needed. In many cases a four channel oscilloscope would actually do the job. 

There are lots of ways to get around many of the perceived shortcomings in some LAs.  Of course if you really need lots of channels you can get a large LA.  I believe my vintage 16500C with five boards plugged in will give me 200 state channels at 100Mhz, 4 channels for clocks, with four 250Mhz (1G sample) oscilloscope channels all synced together to zero into really difficult timing problems. Triggering options are extensive. There are also smaller portable analyzers that have up to 136 channels at 150Mhz state with 500Mhz timing.   Of course these are not as cool as one that runs on your laptop and decoders are much harder to do but a mix of a USB based, maybe 16 channel, modern one with a high channel count vintage model might make for a much more useful setup.  Of course a good four channel scope with high bandwidth will show stuff you may never see with an LA. 

[Dylan Hall]

I have the Picoscope 2206B. It's only 16 digital channels and is at the expensive end of the spectrum. However, the two analogue channels have proven useful often enough to justify the compromise. I also have the added requirement that the software must run on a Linux desktop which narrows the options somewhat.

Dylan

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[7alken]

hi Mark, not much LA experience here yet (soon I hope), but recently I peeked into this also when I looked for oscilloscope, if it is somehow nice to have LA with it integrated; I went with one cheaper and older Siglent which has some weird custom hdmi-like connector and needs expensive (active) LA brick (not expecting it), as I have in fact here for a while already Digilent Digital Discovery, expecting this will be enough for what I plan --  ...its 3V3 powered but has 5V tolerant inputs, but threshold only at 1.42V for these inputs (3V3 outputs) - this was not so expensive, but that LA5032 is probably far better thing

https://cz.mouser.com/en/new/digilent/digilent-digitaldiscovery-module/?utm_id=506177819&utm_marketing_tactic=emeacorp&msclkid=6b6d58fac6a11b37f9c43265a2cb1635&utm_source=bing&utm_medium=cpc&utm_campaign=Digilent%20Supplier%20Czech%20Republic&utm_term=Digilent%20Digital%20Discovery&utm_content=Digilent%20Digital%20Discovery
https://cz.mouser.com/en/ProductDetail/Digilent/410-338?qs=Mv7BduZupUhYmUUUdFKS9A%3D%3D
https://cz.mouser.com/pdfdocs/Digital_Discovery_RM_Web.pdf
(this is datasheet and last paragraphs mention that threshold, fixed ..)

while searching I found also some weirdo modern way, ngscopeclient software with some magic ways to setup triggerings and combine scopes and LA, but only for very brave warriors maybe )))
it is expeected to support more devices (not that LA5032 though) ... guy who works on this had also older version "glscopeclient" and there i some ThunderScope hardware, but its only FAST scope
(many pro devices arent do good, internally they are not so fast but this is about 500MHz, again, because of SI - but I relaxed around this with unlocking the siglent)

https://www.youtube.com/watch?v=Sx9cRnWOk2A
https://www.crowdsupply.com/eevengers/thunderscope
(only if somebody is interestedd also with some new weirdo)

P.

[7alken]

btw, for that pico thing here John Winans glued 4 of them but found something in firmware to work on ... its  in good hands, I feel ))
https://www.youtube.com/watch?v=S5vlARRwfCc
https://www.youtube.com/watch?v=c1qEvPajQzI
P.

[Rob Gray]

I was looking at this model a while back

https://www.dreamsourcelab.com/shop/logic-analyzer/dslogic-u3pro32/

I have an old Logic 8ch so still haven't bought this one but probably will, I did download the software and like that.

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Regards
Rob

GRAYnomad ❖ Nature photographer extraordinaire PO Box 450, Gin Gin, QLD 4671, Australia ☎ 0428 920 333, +61 428 920 333  www.robgray.com       r...@robgray.com

[Mark Durham]

Tadeusz, the FNIRSI DLA-32 looks interesting. I've got one of their DPS-150 mini power supplies to power my RCBus projects. I will download their software to see if it has a demo mode.

Rob, I was also looking at the DSL 32 channel device. At first glance both devices appear to have similar specs but the FNIRSI device is around 200 GBP whereas the DSL device is around 360 GBP.

One thing both seem to have in common looks to be quite short signal leads. I guess that is to be expected with high frequency signals. The ancient Tektronix 3001GPX I used at work had quite long cables but they went into a small signal conditioning pods (I guess that's what they were) before the final short (15cm?) signal lead to the probe/clip.

Mark.

[Tom Storey]

A couple of years ago I bought myself a DreamSourceLab DSLogic U3Pro32 to upgrade from a Saleae 8 channel. I would say quite confidently that I am impressed so far. It wasn't cheap, but it was a heck of a lot cheaper than a 16 channel Saleae, which I just couldn't justify the price of.

Their software (DSView) is a fork of Sigrok, and there was some contention around that some time ago because (I think?) they claimed it was their own without crediting Sigrok. That has (I think?) been addressed now.

But with this new setup I took the opportunity to learn how to write protocol decoders, and have written one for the 68000 bus, screenshot attached. The more signals you add to it, the more it can decode and show you (this was just after adding some interrupt support). Their decoding API is compatible with Sigrok as far as I am aware, so if you write a decoder for one it should work with the other. Happy to share my decoder with anyone that wants to give it a try.

I also made one for the 286 when I started playing around with that, but I haven't done much with that in a while now.

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[Mark Durham]

Pretty impressive, and thanks for your thoughts on the DSL unit.

[Earth Person]

Greetings,

Back in 2019 I purchased the DreamsourceLabs DSLogic Plus. It does well. Kinda wish I had a better bench unit, but I don't have the room for one. I use it a lot with 6800 projects and easily need more channels. So if you can get one with over 16 channels, that is great. Some tout that DreamsourceLabs U3Pro32 is good to use. The software is okay.

- William

[Ed Silky]

Hi,

For those that have the DSL unit... I'm looking at the LA5032 to upgrade my LA5016 (to give me 32 channels), but I'm open to others. Does the DSL U3Pro32  support triggering on something other than a single signal?

-Ed

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[Joao Miguel Duraes]

I use several GusmanB logicanalyzers chained together when I need more than 24 channels:

Open source, cheap and cheerful: https://github.com/gusmanb/logicanalyzer

M

[Mark Durham]

Ed, Thinking back to what you said earlier, it seems strange that the LAxxxx devices can't trigger on a pattern (if that's the correct phrase). I took a quick look at the user manual for the LAxxxx series and it appears to imply that you can get it to trigger on a pattern match. The manual says:

"Except the edge and level trigger condition for single channel, the logic analyzer also supports the condition combinations of multiple channels, such as levels, one edge and multiple levels. The final condition is the “logical AND” of these conditions, which means the sampling process starts when all conditions are met. In this way, the trigger can be the result of certain parallel data."

Re the GusmanB units, I've taken a gamble and ordered 2 of them - non WiFi - same as your photo. If they don't work out, then I figured I could always sell them on. How do you get on with those dupont connectors on your flying leads? I've used some with my LogicPort LA and it appears that the "spring" inside the female connector slowly loosens over a few insertions and they then don't grip the male pins. Perhaps I have cheap female crimps or I'm beginning to suspect that I may have cheap male pins that don't have such a nice chamfered point to them.

Mark.

[Joao Miguel Duraes]

Hey Mark,

Yes, there are cheap dupont leads and then very, very cheap ones. I have them both. It depends on what you attach them to but I always double check, just in case.

I reserve the cheaper ones to solder points or THT pins. The nicer quality ones I then attach to finer components, SMD, etc. It's trial and error but not too onerous to get it right. 

I've recently spent some time with them on my TurboSound module, monitoring both the pins and the SMD Atmega8 (very fine). It was good with only a couple of jumps early on.

I got a batch of 5 Gusmans done at JLCPCB - under $100 for the lot with me then adding the Pico 2/2Ws - I have plenty around. I could not justify spending more than that for what is effectively a hobby for me. 

As a side note, I'm currently studying an RCBus snooper module to reduce how many leads I then need on the Gusman. 

M

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[Ed Silky]

Hi Mark,

I've never seen a way to do it in the menus. I'm away from my shop for a couple weeks, but when I get back I'll dig in and see if it does. 

-Ed

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