What to buy - Dedicated Logic Analyzer vs "The new Scopes" aka. SDS824/DHO924(S) - Page 1
Forum section: electronics / testgear

author: Traceless
author_rank: Frequent Contributor
timestamp: November 28, 2024, 09:33:40 pm
content: Hi everyone,I'm currently in the market for a logic analyzer and was thinking about getting one of thoseSaleae Logicones. However I also noticed that the new generation of 12 Bit scopes aka Siglent SDS824 and Rigol 924(S) double as logic analyzers too at a similar price point. In addition to both being a logic anayzer they'd also be a big upgrade over my current scope (Hanmatek DOS1102). So before pulling the trigger I have a couple of questions. One being: How good do the Siglent SDS824 and the DHO924 work as logic analyzers? Is this just a gimmick added on for marketing or is the feature productively usable?I also tried to read up on the Siglent SDS824 vs Rigol 924(S) discussions here on the forum. While both seem to have similar features the most noticable distinguishing mark seems to be the general opinion that the Siglent is much more usable/stable/polished than the Rigol. The DHO devices apparently have been plagued by a lot of bugs, weird glitches, slow patching on the side of Rigol. Is this still an issue?Other than that I like the exterior design and compactness of the Rigol, but find the UI to be way to busy and generally not so well designed, whereas the Siglent uses more bench real estate but seems to have a much cleaner UI design.Currently I'm leaning towards buying the Siglent, however I'd be able to grab a DHO924 40% cheaper that the Siglent scope. So before pulling the trigger I'd like some second opinions. Most importantly:1. If any, which of the scopes works best as logic analyzer - or should I forget the scope idea entirely and go for the dedicated analzer?2. Is the SDS824 worth a 40% markup over the DHO924?3. If I'd go for Rigol, is getting the 924S version with signal generator worth it (or in other words how useful is the signal generator feature)?Cheers Traceless

author: TimFox
author_rank: Super Contributor
timestamp: November 28, 2024, 09:41:30 pm
content: The signal generator in the Rigol 924S works well.However, the "Bode plot" function that uses it as a source to measure gain and phase does not give accurate results.

author: artag
author_rank: Super Contributor
timestamp: November 28, 2024, 10:37:34 pm
content: All these 'logic analysers' are a bit disappointing. They're not logic analysers at all, they're multichannel (for values of multi mostly in the range 8-16) 1-bit oscilloscopes. Some - especially the ones built into scopes - don't even have a proper trigger on the digital side. At best, a single word match. No clock input.Even the Saleae, which is a delight to use as far as it goes, can't do a clocked state trigger like a proper logic analyser.That might be fine for your intended usage, but do think it through. After a period using mixed-signal scopes and USB analysers I've gone back to proper logic state analysers for debugging old microprocessor hardware.

author: Traceless
author_rank: Frequent Contributor
timestamp: November 28, 2024, 10:56:27 pm
content: @Tim thanks pointing out the bodeplot issue and your experience with the signal generator.@artag: Sure clocked state trigger would be great to have. Would you mind sharing which "proper" logic analyzer you currently use?

author: ataradov
author_rank: Super Contributor
timestamp: November 28, 2024, 11:07:48 pm
content: Logic analyzer on DHO924 is a miserable experience. It is a total waste of time. Same goes for the signal generator. Signal generator lacks very basic features. Like it can only set integer value for the duty cycle and generally settings are very limited. There are more settings on a basic siggen from AliExpress.Get dedicated tools, they will always be better.

author: tggzzz
author_rank: Super Contributor
timestamp: November 28, 2024, 11:31:31 pm
content: A lot will depend on what you are trying to find and, more importantly, ignore.If your digital signals are serial comms, then decoding messages may be better with a protocol analyser. Consider a BusPirate5.Make sure whatever you use allows you to filter out irrelevant stuff. That means only triggering/capturing data on a clock transition (i.e. the logical states), and/or when certain conditions are met (e.g. read/write to a specific address/register).

author: 2N3055
author_rank: Super Contributor
timestamp: November 28, 2024, 11:46:41 pm
content: Quote from: Traceless on November 28, 2024, 09:33:40 pmDHO900 is not a very good scope. They are dropping prices so much for a reason.SDS824 is in different class, for many reasons, and fact is that they don't need to drop prices at all tells you all you need to know.And for private use you might not need SDS824xHD, SDS804xHD might be better choice.And if you get a separate AWG from Siglent (like SDG1032X that is on sale now) for price difference, you will get profesional scope and awg that together do very good Bode plot.As for logic analysers that is a weird topic.Logic analyser is actually an old school massive parallel device that have very sophisticated triggering (both in paralel and various state machine settings), external clock options etc etc. It was used to monitor whole buses, backplanes etc.As time went on, these devices were not made anymore (digital designs went on to slow/fast serial busses, or parallel buses that were too fiddly to connect probes to it).USB devices like Saleae are serial protocol interpreters, mostly. Few of them even support external clock, and triggering is very primitive to moderately capable. They are mainly used to decode serial protocols messages for software debug.If that is what you want to do, USB protocol analysers are better choice than MSO scope.For moderate amount of decoding on serial buses (CAN/LIN/SPI/I2C/UART or similar) a 4 channel scope might be all you need.Maybe a bit more detail of intended use?

author: Traceless
author_rank: Frequent Contributor
timestamp: November 29, 2024, 12:20:38 am
content: Hi 2N3055,thanks for your feedback.Quote from: 2N3055 on November 28, 2024, 11:46:41 pmI was also considering the 804X at first, especially since some threads here in the forum suggest you can "upgrade" it to an 824X. However the 804X only comes with 70 MHz probes if I buy the 200MHz ones separately I might just as well go for the 824X. As for the AWG I already own a UTG962E which is currently absolutely sufficient for my purposes. However the price difference between the Rigol DHO924 and DHO924S is currently not that big, so if the function generator in the scope would be okay it wouldn't hurt to have a 2nd one at hand.Quote from: 2N3055 on November 28, 2024, 11:46:41 pmWell Siglent actually offers more or less "proper"logic probe extensionsfor their scopes (Rigol as well), which according to the specs should perform similar to the Saleae. So the idea here was thatifthe implementation by either Rigol or Siglent was good I could basically get a logic analyzer and an upgraded scope as bonus for a similar or lower price than the dedicated logic analyzer from Saleae. As for the inteded use: A current project would be to capture communication between components in embedded devices, for example the communications between a TPM module, CPU/microconroller and memory.

author: 44kgk1lkf6u
author_rank: Regular Contributor
timestamp: November 29, 2024, 04:55:27 am
content: https://siglentna.com/wp-content/uploads/2023/04/SLA-1016-Whitepaper.pdfThe document I found on their website seems to say that it does no more than adding some digital channels to the oscilloscope. (But it has so much stuff inside. Maybe they are just bad at advertising.) Just like the other things that others said are not real logic analyzers, it seems to lack some features that I would expect a logic analyzer to provide.Sampling on a clock input. This means the X axis will be clock cycles instead of time. I find it easier to read a screen when each line is a data transmission than when I have to scroll to find the clock signal switching and then look at what the data signals are. It also means the max sample rate and the max sample duration are available at the same time.Only storing changes. Another way to avoid having to choose between sample rate and duration.A programmable trigger state machine. For example triggering when a sequence of words are transferred on a parallel bus following another sequence of words being transferred on another bus within a certain delay.Also note that a logic analyzer that has these features may lack some features such as decoding SPI.

author: ebastler
author_rank: Super Contributor
timestamp: November 29, 2024, 07:06:06 am
content: Quote from: Traceless on November 28, 2024, 09:33:40 pmIf you are specifically interested in using the digital channels, I'd say the answer is yes.The DHO924 has 1.25 GSa/s total acquisition rate, which is already on the low side. (Only 312 MSa/s in three- or four-channel mode, i.e. not sufficient for the stated bandwidth of the scope.) If you enable the digital channels, they cut that sampling rate in half! An unusual design for a mixed-signal scope, and it leaves you with somewhat crippled analog channels.The SDS8..X HD has a more generous 2 GSa/s to begin with. The optional logic probe comprises its own sampling subsystem in the external unit. Which implies some limitations (e.g. no mixed-signal triggering), but also means that you get 1 GSa/s for the digital channels without affecting the analog sampling rate at all.In general, a dedicated PC-based logic analyser will give you more screen space, a more tailored UI, more signal decoder options. The built-in logic analysers in the scopes will make it easy to view and correlate analog and digital signals. I'd say it depends on your application which solution works best.However, when you state that the Salea logic analysers are "at a similar price point" as the entry-level 12 bit scopes, that can only refer to Salea's most basic "Logic 8" -- only 8 channels and 100 MSa/s. Again, it depends on your application whether that's enough. There are B-brand alternatives with better hardware performance, e.g. the DSLogic series from DreamSourceLabs, although with less refined software.

author: kripton2035
author_rank: Super Contributor
timestamp: November 29, 2024, 07:20:17 am
content: don't forget you can use sigrok app to connect to these scopes if they are connected to the same networkyou will get a ton of protocols decoders, and more memory to store that signal.more here :https://www.eevblog.com/forum/testgear/new-sigrokpulseview-hardware-support-(siglent-sds-hd-rigol-dho800-)/msg5555753/#msg5555753

author: Traceless
author_rank: Frequent Contributor
timestamp: November 29, 2024, 08:49:37 am
content: Quote from: artag on November 28, 2024, 10:37:34 pmQuote from: 44kgk1lkf6u on November 29, 2024, 04:55:27 amI see that the missing trigger feature is a weakness. But since both the scopes and the Saleae logic probe suffer the same weakness I'd call it a tie between the dedicated probe and the scopes in that regard. That being said in the thread that kripton2035 linked there is a screenshot of the sigrok application showing a capture of the 16 data channels on the Siglent scope overlayed with the scope's channel 1, in the bottom right corner there is a box "Trigger C1 DC".Does that mean I could use the analog input channel of the scope to trigger on a clock signal for the logic probe or is this just an unrelated overlay?Are there any logic analyzer options with capabilities similar to the Saleae that would provide the missing trigger feature? I mean sure a Keysight 16861A would probably be a nice device but a) its probably massive overkill for my applications and b) if the only price you can find is "get an offer" on the Keysight website that usually means you can probably sell your car and/or your house and still not have enough money to afford the device(Note: I'm in the EU, so used, reasonably priced Keithley/HP gear that is not a complete basket case is basically unobtainium)Quote from: ebastler on November 29, 2024, 07:06:06 amOkay based on that observation plus what I've read on other threads and the comments of ataradov and 2N3055 about the DHO924 I can definitely rule out the Rigol already. So the race is between Saleae and Siglent SDS 824 + SLA1016.Quote from: ebastler on November 29, 2024, 07:06:06 amIIRC you can hook up the new scopes to an external monitor via HDMI, or see the display content via a Desktop application, which would at least solve the screen real estate problem.Quote from: ebastler on November 29, 2024, 07:06:06 amWell maybe I was using the term "similar" to liberal here. The Siglent SDS824 + SLA1016 costs somwhere around 1100-1200€, the Saleae 1700-1800€. Since a good instrument is pretty much a one time purchase I consider that to be still in the same ballpark aka. "similar". As a counter example the Keysight 16861A is not available at a "similar" price point with high likelihood

author: btest
author_rank: Newbie
timestamp: November 29, 2024, 08:55:45 am
content: (My first post!)I've been doing embedded software for going on 30 years now and my needs have definitely changed over the years. I own an Agilent 16903A logic analyzer that I haven't turned on in years. I also own a Saleae that I haven't taken out of its case in years. It comes down to what are you trying to look at. If you are trying to analyze the handshake between 2 devices use a PC based logic analyzer. if you are trying to look at signal integrity (eye diagram, noise, jitter) then you will need a scope. At the end of the day you probably need both. And I have never found a scope that had actually useful logic channels. The ones I tried in the past could only do serial decode on the analog channels - go figure. Not sure how true that is today.The instrument I go to most lately is a DreamSource DSLogic U3pro16. With it I can sample at high rates and get long (10+ minutes or more) captures of serial data. I2C, SPI, UART and lately a lot of CAN. It's real easy to scroll through the data or it can be exported. If you use buffer mode it has multi-stage triggering. The app is based on Sigrok and is open source. It's the depth of capture that makes these so valuable. Even the best scopes are limited as to memory depth while the DS just pushes the data over USB to your hard drive. One thing that is often not mentioned is the DS has terminated coax flying leads while analyzers like the Saleae is just a wire. It makes a difference, trust me, when you are looking at higher speed signals.But there are times when a scope is your only answer. I have been debugging a CAN device that seems to lose arbitration with itself as it is the only device transmitting on the bus. It sends out a handful of bits, stops and then immediately retries the message. While this event is visible on the DS it does not have the ability to trigger on Start-Of-Frame like my scope can so you spend a lot of time looking for it in the data. The ability to trigger on SOF is also important to do things like generate an eye diagram. That being said, if I were buying a scope making sure it had all the licenses necessary for protocol decoding and analysis would be my first priority.

author: ebastler
author_rank: Super Contributor
timestamp: November 29, 2024, 11:11:14 am
content: Quote from: Traceless on November 29, 2024, 08:49:37 amBut even the top-model Saleae (Logic Pro 16) gives you very limited analog capabilities: 50 MSa/s max., and no analog probes included at all. So you should really compare to to a combination of SDS804X HD + SLA1016, which comes at half the price of the Logic Pro 16. Or maybe a combination of SDS8..X HD and a DSLogic U3pro16 or similar?QuoteThe Siglent scope does not have an HDMI output, but you can use the web interface to view the screen (and drive the scope via the mouse or touch) from a web browser. The update rate is reduced vs. the built-in screen, but it is certainly usable. But since the UI was designed to work with the small screen, it is still a bit limited compared to Saleae or similar logic analyzer software which was designed for a large monitor from the start.Edit: Typos...

author: tggzzz
author_rank: Super Contributor
timestamp: November 29, 2024, 11:13:15 am
content: Quote from: btest on November 29, 2024, 08:55:45 amWelcome to the forumThose points areveryvalid. Unfortunately too many people don't understand the distinction between analogue waveforms (e.g. TTL/CMOS/etc) and digital signals. Use the analogue domain tool to verify and validate analogue signals, then flip to the digital domain and use digital domain tools to verify and validate digital signals.QuoteMy preference is to have two tools each of which is good at one job, rather than one tool that is poor at two jobs. Of course that implies knowing what "the job" entails; for digital signals to sort the wheat from the chaff you need good filtering and triggering.The one area where a single toolmightbe more capable is where it is necessary to have an analogue signal trigger the digital tool, or a digital signal trigger the analogue tool. However, the limitations of a specific toolmightmake that impractical, and skill and imaginationmightmean it can be achieved with two separate tools. The only way to assess that is to define a use case, then carefully read and understand the user manuals (not the datasheets!).

author: Traceless
author_rank: Frequent Contributor
timestamp: November 29, 2024, 07:18:24 pm
content: @btestHi welcome to the forum and thanks for reporting your experience with the DreamSource DSLogic U3pro16. Since @ebastler also brought this device up earlier I took a closer look and hardware-wise it looks really nice. However ebastler mentioned "less refined" software. Does less refined mean less features or really bad design/lots of bugs? I took a look at the DSLogic github repo, OpenSource is definitly a plus, however development does not seem to be super active. The sigrok wiki states that support for theDSLogic U3pro16is planned (no mention of the 32 channel version). If the software is good I might as well consider to get the SDS824 without the SLA1016 and get the DSLogic U3Pro32 as a standalone logic analyzer, it does not cost much more than the SLA1016 addon from Siglent. Also is there any reason *not* to prefer the 32 channel version of the DSLogic over the 16 Channel version, e.g. missing software support?@tggzzz: I also took a quick look at the bus pirate that you mentioned earlier, it seems to be an interesting little device. The website unfortunately seems to lack a manual so its hard to tell from the brief specs and texts to tell what it can and can't do compared to the other devices discussed here.BTW: As far as I can tell from the specs the SDS824 has more memory than the lower SDS8XX versions. I assume using the unofficial upgrade path 804X -> 824X will unlock the 200MHz bandwidth but the additional memory is physically missing? Has anybody tried and can confirm that?

author: tggzzz
author_rank: Super Contributor
timestamp: November 29, 2024, 08:24:06 pm
content: The buspirate 5 is an interesting device that does more than capture and process data. It cannot easily be characterised in conventional terms, since it is in a different niche.There is a lot of information on the website and forumhttps://forum.buspirate.com/, but not a conventional manual. The principal creator is active there, and the natives seem friendly.It is open source, so in theory you could create addons - but that wouldn't be trivial.Overall it is useful to know the tool exists, so that you can use it when your needs fall into its niche.

author: btest
author_rank: Newbie
timestamp: November 30, 2024, 02:21:38 am
content: Quote from: Traceless on November 29, 2024, 07:18:24 pmTraceless,Sorry, I did not mean in any way to imply that the software was 'less refined'. I think it being based off of Sigrok is a good thing. I was just saying to not expect it to have the triggering capability of a scope, but I do not know of any PC based logic analyzers that do. The fact that it has multi-stage triggering puts it above almost all of the others, although that's a feature I have maybe used twice over the years. The strength of a PC based LA is the ability to do long captures for post analysis. You do not need fancy triggering to do that. I've only had the software crash a couple of times over the years and cannot remember the last time it did so.Just for grins I got my Logic Pro 8 out and downloaded their latest software. It's come a long way since the last time I used it. But at over 3x the price of the DSLogic I don't see how anyone can justify it. Turning the Analog channels on puts such a limit on the sample rate that for me it becomes pointless. As tggzzz said: "My preference is to have two tools each of which is good at one job, rather than one tool that is poor at two jobs". I think we have all learned that lesson the hard way. Worst case you can always run the trigger out of the scope into an LA input to time correlate domains.I also want to point out you need to buy for your specific needs. I write embedded control software on many different platforms but at a top level its all the same: gather data from multiple sensors, analyze it and generate a control output. My last job one of the inputs was IMU data at the rate of 4000 messages per second over a UART. My current job is primarily a combination of CAN and UART. In the digital domain the DSLogic has easily met all my needs. I am not sure what you are trying to do but take a good look at what type of signals you are trying to analyze and buy the appropriate tools. You can download the DSView app and run it in demo mode before buying the hardware. Same with the Saleae.As much as I do in the digital domain there are times where you have to be in the analog domain. If you get noise coupled onto your signal lines the LA will show you the invalid transitions but to really see what is going on you need a scope. It's the only way to see how much your square wave has rounded off when sent over long cables. Or, like in a case I had a couple of years ago, where the EE team tried to get away with just using the RC clock internal to a STMicro instead of putting an external crystal oscillator on it. Worked great until it got warm. Then the RC clock drifted so much that it corrupted the CAN bus timing. Not obvious on the LA but clearly shown on the scope doing an eye diagram.Hope this helps. Again, I can only relate to my needs which I am sure are not the same as yours and these are the tools that make me most efficient.Just realized I missed your comment on 16 vs 32 channels. The issue with any PC based LA is USB bandwidth. The more channels you have active the lower the max sample rate. For me personally I rarely have more than 7 or 8 active channels and typically its 2 or 3 so 32 channels is way way overkill so I did not spend the extra $100. Again, it's what meets your needs. It's the same software for both, and with 3 channels or less they both can sample at 1GHz. For 6 channels it's 500MHz, etc. I have no experience with Siglent scopes so cannot make any comments there.

author: JimboJack
author_rank: Regular Contributor
timestamp: November 30, 2024, 07:02:28 am
content: My take is1. check the min pulse width they can detect on.2. purchase a 'High speed' USB 2.0 isolator. supporting 480Mbps , I have not got around to using a USB 3.0 isolator 'superspeed' be on my next moveBe a good EEvblog video to see how they fairas mentioned check the waveform in the osciliscope then use a PC logic analyser with opensource tools to data capture, then you can decode CPU instructions later.

author: tggzzz
author_rank: Super Contributor
timestamp: November 30, 2024, 09:48:34 am
content: Quote from: btest on November 30, 2024, 02:21:38 amJust so, hencemyreluctance to make A Pronouncement on this topic. (Doesn't stop me on other topics, though)The more difficult triggering example is where a digital signal needs to trigger the analogue capture, e.g. when writing a specific value to a specific register might be causing analogue infelicities. Naturally if you don't need that, you don't need that, and often some skill and imagination can compensate for tool deficiencies.

author: Kean
author_rank: Unknown
timestamp: November 30, 2024, 10:12:41 am
content: Quote from: tggzzz on November 29, 2024, 08:24:06 pmThe Bus Pirate 5 can operate as a basic logic analyser, but also so much more. It can also act as a device programmer, and supports many protocols like 1-Wire/SPI/I2C/UART/IR/analog for debug and reverse engineering. Think of it a bit like a swiss-army knife for embedded developers.Usage does require some practice, and there is a learning curve compared to some other device - but it is incredibly versatile and extensible. There are also various adapters and accessories available to help get started.The better doc site for exploring the capabilities of bp v5 ishttps://firmware.buspirate.com/

author: Traceless
author_rank: Frequent Contributor
timestamp: November 30, 2024, 01:22:08 pm
content: Quote from: btest on November 30, 2024, 02:21:38 amHi btest, no worries you didn't imply that the software was less refined, it was ebastler who actually mentioned this:Quote from: ebastler on November 29, 2024, 07:06:06 amSince I don't have hands on experience with either the Saleae nor the DSLogic I thought I'd double check with you and ebastler, who based on the comment also seems to have some experience either with the device or at least the sofware, how to interpret "less refined". I just wanted to make sure that I'm not running into buggy banana-ware situations as was reported in context of the Rigol scopes on multiple occasions in the forum.Quote from: btest on November 30, 2024, 02:21:38 amI'm actually very grateful for you helping me out with your very first post here on the forum, and ebastler commenting on the same device. Together with all the input from other users here on the downsides of the scope based solutions I decided to go with the DSLogic U3Pro32. I could still get the SDS824HD without the SLA1016 as standalone scope, albeit I'm currently considering to just stick with my current Hanmatek DOS1102 for now.Quote from: btest on November 30, 2024, 02:21:38 amQuote from: tggzzz on November 30, 2024, 09:48:34 amCurrently I'm mostly interested in reverse engineering finished designs. Thus I don't expect to have to deal with analog design/noise issues because the designers of the DUT probably have figured this out already. As mentioned in my post above currently I'm interested into investigating the communication between Memory, CPU/Microcontroller andTPMs. I've also worked with CAN-bus communication in the past, however currently there is nothing CAN-related in the pipeline. I'm sure once I have the analyzer I'll quickly come up with more use cases. So buying a device with some headroom might just save me a redundant upgrade purchase later down the road.One sophisticated use case in context of the TPM scenario would bedifferential power analysis. A stand-alone logic analyzer is not the right tool for that and the Scope/Logic combos might be more useful here. The basic idea here is: Cryptographic operations involve a key, depending on the key bits power consumption changes. As a simple example theSquare-And-Multiplyalgorithm squares in each step but if there is a one bit you also have an additional multiplication operation which increases the power consumption. Of course you have to correlate your power consumption with key-based instructions somehow. If this is observable the issue is called "side-channel". Apart from the power consumption there is also often an observable timing difference (due to the different number of instructions in key-bit dependent code paths). Proper implementations will be "constant-time", i.e. perform "unnecessary" dummy operations so that both code paths for 1-bits and 0-bits in the key use the same amount of time, and power. This prevents leaking information about the secret key through timing and/or power consumption.Quote from: btest on November 30, 2024, 02:21:38 am32 channels are indeed a lot. But double the channels for 100$ extra seemed like a no brainer. Even if I don't need the additional 16 channels, DSLogic sells the fly-wires for 25$, so the additional wires alone are worth the price difference. Plus currently they have a sale so the 32 channel version is sold at the 16 channel version price@Kean: Thanks for the bus pirate link I'll take closer look later. At its price point it might be worth to just get one and see what it can do. Currently I'm mostly using the el-cheapo USB-Uart adapters, and a RT809-F, T48 or CH341A for programming.

author: tggzzz
author_rank: Super Contributor
timestamp: November 30, 2024, 01:38:34 pm
content: Quote from: Traceless on November 30, 2024, 01:22:08 pmAlternative strategy: buy something cheap that will allow you to understand what you really need to spend money on.QuoteYou should understand a scope's ENOB as a function of frequencies. That's particularly important when you are subtracting two nearly equal numbers. Z=X-Y, where X and Y are +-1% doesnotmean Z is +-1%!I suspect you would benefit from an analogue tool dedicated to generating an analogue signal that is related to the power, and capturing that signal on a scope.

author: ebastler
author_rank: Super Contributor
timestamp: November 30, 2024, 01:41:10 pm
content: Quote from: Traceless on November 30, 2024, 01:22:08 pmI'd rather defer to people who have used the Saleae or DSLogic in earnest, or ideally both. My own experience with the software is only based on trying a cheap 8-channel "logic analyser" module with both, Saleae's software and Sigrok (on which DSLogic have based their software).I just never quite "got" Sigrok, while Saleae's software seemed more logical and consistent to me. I have had similar experiences with other open-source projects, e.g. picture, video, audio editors: While they are powerful, they often can't hide their "design by committee" and "I'll implement my favorite feature here!" background.A while ago I downloaded the DSLogic software since I was contemplating to buy one of their U3pro units. My impression was that while they had re-skinned Sigrok to make it look cooler (dark theme!), the UI logic was still largely the same. Usable, but not very satisfying (for me, personally). On the other hand, I would not expect bugs to be a major issue, since the underyling Sigrok base is pretty mature.I never pulled the trigger on actually buying a better logic analyser -- thinking it over, I did not really have a need for more than the 4 channels of my scope so far. So again, someone who has used the actual DSLogic or Saleae units can hopefully provide better insight.

author: ebastler
author_rank: Super Contributor
timestamp: November 30, 2024, 01:57:43 pm
content: Quote from: tggzzz on November 30, 2024, 01:38:34 pmI agree that this may be a challenging project -- both on the analog side (picking up the potentially small power variations, which may sit on an uncorrelated background of other fluctuations), and on the digital/logic analysis side (getting from the fluctuation patterns to the actual key).But if the planned approach involves physically opening the device and tapping into as many digital signals as you can access (outside of the chip under investigation), then it would certainly be a use case which benefits from a mixed-signal scope which captures and displays the analog and digital channels in sync.

author: Traceless
author_rank: Frequent Contributor
timestamp: November 30, 2024, 02:29:26 pm
content: Quote from: ebastler on November 30, 2024, 01:57:43 pmChallenging - definitely. I might be wrong but I think background noise might be less of a problem if you applydifferentialpower analysis. You repeat your measurement multiple times and then correlate the signal across many experiments lets say a dozen or maybe a few hundred. This should basically eliminate your noise floor leaving mostly the common signal across all experiments intact. The tricky part is, that all your measurements need to be exactly over the same key related instruction sequence. I.e. every trace must start exactly when the crypto operation begins and stop when it ends.

author: tggzzz
author_rank: Super Contributor
timestamp: November 30, 2024, 03:16:45 pm
content: Quote from: Traceless on November 30, 2024, 02:29:26 pmWell, "the solution to all signal processing problemsisto integrate for longer".Nonetheless it helps to reduce noise and increase the signal (as far as possible) before measuring it.

author: awakephd
author_rank: Regular Contributor
timestamp: November 30, 2024, 05:48:20 pm
content: Quote from: Traceless on November 29, 2024, 07:18:24 pmIt doesn't look like anyone has answered this bit (apologies if I just missed it).The upgrade path not only unlocks the bandwidth, but also the additional memory. IOW, the physical memory is present in the 804, just disabled.

author: nctnico
author_rank: Super Contributor
timestamp: November 30, 2024, 06:23:41 pm
content: I don't think the really cheap scopes bring much to the table where it comes to logic analysis due to limitations in triggering, display abilities and memory. Same for low cost USB 'logic analysers' which offer very little in terms of triggering. If you want to dig deep into a protocol, then a real logic analyser like Tektronix TLA700 / TLA7000 series is a much better option due to having elaborate trigger sequencing. Recently some information got released for these series of logic analysers (https://groups.io/g/logicanalyzers/topic/109776434#msg803) which seemingly allows to create all kinds of wild protocol decoding algorithms to run on the logic analyser itself.But that is not where it stops. On the TLA700 you can use the TLA7AA4 module which has 125ps time resolution (albeit in a short buffer). On the TLA7012 mainframe, you can use the TLA7BB4 module which has (IIRC) 25ps time resolution (albeit in a short buffer). On top of that these modules have analog outputs which allow to pick up any signal from the probe and feed that into an oscilloscope. Using the trigger output, this allows to show an event both in the analog and digital domain with extreme resolution (assuming using a low noise 12 bit oscilloscope). And I'm not done yet... The modules can use active FET probe heads which have a bandwidth of around 2GHz and which can be fitted straight onto a circuit board using a specific footprint. So if you want to analyse a TPM module, create an interposer board for it which can connect to the logic analyser probe and you can look at the signals through an almost perfect probing system.Last but not least: these logic analyser systems aren't even expensive. Lowball some of the sellers on Ebay and I'm sure one will bite.

author: Traceless
author_rank: Frequent Contributor
timestamp: December 01, 2024, 11:50:17 am
content: Quote from: awakephd on November 30, 2024, 05:48:20 pmHey awakephd, thank you for commenting I started readingyour thread, didn't get all the way through though. Thank you for clarifying that the memory is present in all models.Quote from: nctnico on November 30, 2024, 06:23:41 pmHey nctnico, the TLAs sound tempting. I took a quick look at ebay there are tons of versions and addons there so I'd have to do some research before being able to tell them apart. But at a glance I currently see two problems. The items seem to be in the 2000-4000€ ballpark not sure low-balling @500€ will work. The 2nd and bigger problem might be - it won't fit on my bench. I mean technically it will fit, but it will occupy the whole working area. A side rack/shelf on wheels would be a possible solution but that would require extremely long probe leads which I assume is gonna cause all kinds of issues at high frequencies.

author: pdeal
author_rank: Contributor
timestamp: December 01, 2024, 01:53:28 pm
content: I had a salea logic pro 8 but sold it. It worked well for my needs which was decoding spi signals. I had two complaints with it. The first is that the usb aspect i found to be a pain. Working on a project it seems to complicate and clutter life a lot having to use the pc both for writing and debugging code and as another instrument. I prefer stand alone instruments. The second is that while the salea works well it’s very expensive for what it is. A lot of what they’re selling will that is cuteness. So I sold it for pretty close to what i bought it for. I bought instead a scope with logic inputs with the proceeds. Haven’t yet used it so i can’t say if that was a good move or not.Another thing, the salea analog inputs are a joke. Maybe for a few hundred hertz but for anything faster forget it.