Oscilloscope for Arduino/Raspberry Pi projects. 2 or 4 channel? Critical specs?  - Page 1
Forum section: electronics / testgear

author: max100
author_rank: Newbie
timestamp: August 16, 2016, 05:54:49 pm
content: Hi, I am an inexperienced hobbyist in need of help selecting an oscilloscope for Arduino/Raspberry Pi robotics projects.I will be working with sensors, servos, motors etc. and control systems.I am currently looking at the Rigol DS1054Z 50MHz with 4 channels and the Siglent SDS1102CML 100MHz.Simon Monk's helpful book says "make sure it comes with a bandwidth of at least 100 MHz" which might rule out the Rigol except that I read it is hackable to 100MHz.Do I need 4 channels?Will really appreciate benefit of experienced/expert opinions.Many thanks.

author: Fungus
author_rank: Super Contributor
timestamp: August 16, 2016, 06:13:43 pm
content: Quote from: max100 on August 16, 2016, 05:54:49 pmThe Rigol can unlock a LOT of features, 100MHz, extra memory, serial decoders, extra trigger modes, etc.For general use: AnunlockedDS1054Z is better value for money than just about anything else under $1000-$1200.(and unlocking is very easy - use anonline keygenwith your serial number and enter the unlock code)Quote from: max100 on August 16, 2016, 05:54:49 pmYes. Two channels simply isn't enough for anything with lots of I/O pins, serial communication, etc.

author: JPortici
author_rank: Super Contributor
timestamp: August 16, 2016, 06:37:46 pm
content: No, you don'tneedfour channels unless you have to decode full duplex SPI every day or something like that.and in those two scopes the onboard serial decoding is a pain in the ass if you are used to work with better scopeswhen i have to i put out a picoscope which does that particular job superblya 2 channel scope usually have some advantages over its 4 chan counterpart like better hardware (for example dedicated ADC and memory per channel instead of a single one shared by all the channels)so, i would go with a 2 chan scope. keep in mind that all of these entry level scopes are crap. some are less crap than others

author: Fungus
author_rank: Super Contributor
timestamp: August 16, 2016, 06:53:32 pm
content: Quote from: JPortici on August 16, 2016, 06:37:46 pmIt doesn't matter if you do it every day or not. You still need 4 channels even if you only do it once per year.Quote from: JPortici on August 16, 2016, 06:37:46 pmSure, but:a) Itdoeswork, I've used it with complete success.b) The budget appears to be under $400. Saying that $1000+ 'scopes are better than a $400 'scope isn't really helpful.

author: rstofer
author_rank: Super Contributor
timestamp: August 16, 2016, 06:54:23 pm
content: Since SPI is almost always full duplex even if just transmitting 0x00's to receive stuff on MISO, a 4 channel scope is a blessing. That it includes decoding is just frosting on the cake.You probably want to trigger on CS' and view the clock edges against the MISO and MOSI lines. This way you will know that you have the proper CPOL and CPHA settings.So, yes, given only one instrument, a 4 channel scope is much preferred over a dual channel. Four channels plus decoding is the only reason I bought the 1054 because my old Tek 485 has far superior bandwidth. All the extra measurement stuff is nice but pretty much fluff, to me...I was doing this very thing last week with my DS1054Z and it's a treat!The anti-1054 crowd will be quick to point out that you can get a scope that's twice as good for three times as much money. They're probably right! It's all a tradeoff.Now, the other way to do it with a two channel scope is to put the CS' signal into the Trigger input, put the clock into one channel and then either MISO or MOSI into the other. That's the way I did it for years and years. I just had to do the decoding the hard way. I still got stuff to run...Of course, the 485 doesn't have a single-shot capability so I would have to organize my code to write the pattern over and over.You aren't going to find a better scope at the price or even at twice the price. You will find some at three times the price. Check out EEVBlog videos re: this scope. Overlook the jitter problem, that has been resolved.

author: nctnico
author_rank: Super Contributor
timestamp: August 16, 2016, 07:03:00 pm
content: There is no such thing as the anti-1054 crowd. Although there is the 'if you have the money then buy a better tool' crowd. After all $400 is a large chunk of change and if you waste it, it is gone and you'll end up spending even more to buy a proper tool.

author: Fungus
author_rank: Super Contributor
timestamp: August 16, 2016, 07:14:03 pm
content: Quote from: rstofer on August 16, 2016, 06:54:23 pmIt's a blessing for programminganythingwith lots of I/O pins. When you have some spare channels you can get creative with them.eg. I use it quite a lot for software debugging - I might pulse a pin in an interrupt routine just to show the interrupt is alive, stuff like that. The 'scope lets me see things happening in the code.Last week I was programming an MSGEQ7 spectrum analyzer chip. The chip has three control lines and it's good to see all three lines working at once, even if not 100%necessary.

author: rx8pilot
author_rank: Super Contributor
timestamp: August 16, 2016, 07:14:21 pm
content: 4ch is a fantastic option to have if you can afford it. You may only use 1-2 ch most of the time, but the occasions when you are trying to associate the timing between sensors, motor drivers, i2c, etc - 4 channels can save a ton of time or in some cases offer a solution that would be impossible with only 2ch.My first scope was 2ch and I was immediately regretting that decision and bugging my friend to borrow his 4ch.2ch is better than zero channels. 4ch is better than 2 channels. Only you know how bad the cost difference stings relative to what you are trying to accomplish. If cash is tight, I would go after a used 4ch before I considered a new 2ch.

author: Fungus
author_rank: Super Contributor
timestamp: August 16, 2016, 07:20:35 pm
content: Quote from: nctnico on August 16, 2016, 07:03:00 pmQuote from: nctnico on August 16, 2016, 07:03:00 pmI really cant see an Arduino/RPi hobbyist regretting the purchase of a DS1054Z.Quite the opposite: I'm sure they'll be very, very happy with the purchase. It will open a lot of doors.

author: Muxr
author_rank: Super Contributor
timestamp: August 16, 2016, 07:44:17 pm
content: 4ch can come in handy, it's definitely a cool feature.. but 2ch is not that big of a handicap. Countless engineers used and still use 2ch scopes on a daily basis. My main scope now has 4ch but personally half the time I am too lazy to attach all 3 or all 4 probes to the board I am troubleshooting.. I'll more often save a trace and move my probeMaybe it's because I used a 2ch scope for a while, and old habits die hard.For troubleshooting logic buses like some are giving an example of full duplex SPI.. I use a logic analyzer for that, unless I am looking at the signal fidelity. LAs are better suited for the task otherwise (and you should probably pick one up anyways, they are not expensive).Where I think 4ch could come in really handy is if you ever had to do current measurements using the A+B method, with 4ch you might be able to monitor two at the same time, or monitor current and 2 other signals. Current probes are expensive and hard to find and A+B method might be your best shot for that measurement..In either case. 1054z is an incredible bargain of a scope, it's a good buy, there are also good reasons to step up to more capable scopes (even those with 2ch) too. With broad requirements like yours there is no right answer. They are all valid.

author: TheSteve
author_rank: Unknown
timestamp: August 16, 2016, 07:46:08 pm
content: Buy the DS1054Z, enable all features and enjoy it, it is a great little scope.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 16, 2016, 08:12:46 pm
content: I'd go for my combination of a LeCroy 93xx and a cheap Salae clone. But that is just me, of course...

author: dxl
author_rank: Regular Contributor
timestamp: August 16, 2016, 08:26:39 pm
content: Quote from: TAMHAN on August 16, 2016, 08:12:46 pmI'd prefer the Rigol for Arduino stuff, mostly because it'a able to decode standard serial Protocols, and the bandwidth is enough for such low-speed stuff. The old Lecroy stuff is probably also pretty nice, but i think decode capability would be more important for me than other DSO parameters.

author: rob77
author_rank: Super Contributor
timestamp: August 16, 2016, 08:49:11 pm
content: for robotics projects definitely go for the 4 channels... for anything involving quadrature signals and servo drives the more channels the better.so from my side definitely the 4 channel 1054Z , i have one as well as my second scope. but honestly i'm using the 1054Z more often so it's more like a primary scope nowfor those who say spending 400$ on 1054Z is a waste of money... the 1054Z was never meant to be and never will be a high-end scope. it is what it is and actually it's a great value for the money for many users . it's like saying that 15kEur for a cheap dacia duster is a waste of money because there is a much better audi Q7 for 80k+ (same analogy: both are offroad capable but the second one is a completely different league, while the first one is popular because it's cheap and does the job for many users ) .

author: CustomEngineerer
author_rank: Frequent Contributor
timestamp: August 17, 2016, 01:32:38 am
content: Quote from: TAMHAN on August 16, 2016, 08:12:46 pmCare to elaborate why?

author: ian.rees
author_rank: Contributor
timestamp: August 17, 2016, 03:16:36 am
content: For the uses discussed above (decoding IIC, SPI, etc), I'd recommend using a USB logic analyser instead an oscilloscope. I have of those Rigols at home, and use a Saleae Logic 16 at work (the older model - similar speed to the current non-pro models, but 16 channels) and prefer to do software debugging type stuff with the Saleae vs the 1054Z.The Saleae software has a much nicer interface than the scope for decoding, you can look at more digital signals at the same time, have essentially infinite memory, there's less hassle to export data in to a text file for post processing, etc.So, depending on money constraints, I'd suggest any decent scope (likely 2 channel) as a first step, then pick up a logic analyser when you need it. -Ian-

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 05:39:53 am
content: Quote from: Muxr on August 16, 2016, 07:44:17 pmWould those "countless engineers" have had 4 channels if it was cheap and widely available back then?Of course they would...(Did 4-channel analog 'scopes even exist? I'm sure theymustbut I've never seen one. They would have been in millionaires-only territory if they do).

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 05:55:54 am
content: Quote from: CustomEngineerer on August 17, 2016, 01:32:38 amThis is a Lecroy 93xx:Hope you've got aBIGtable....and have some extra budget for theelectricity bill.(...and live in a cold country where an extra heat source in the room is always welcome)PS: Yes, Iknowyou can stand them vertically on the floor next to your chair to save some table space - that's what the triangular feet at the back are for!Quote from: ian.rees on August 17, 2016, 03:16:36 amMaybe, but it's not all good. There's a lot to be said for just seeing things happening on screen instead of hitting 'record', recording a whole load of signals into memory, sit down to analyze it with keyboard/mouse.Plus: Not all 'digital' work is based around decoding long sequences of serial data and dumping the contents of flash memory chips to text files.Me? I'd say hardly any of the work is like that. In the Arduino world there's switches, sensors, analog inputs, PWM signals, etc. This is all stuff you want to see happening live on screen while you press buttons and twist potentiometers. Saleae is no good for that (and for that you need more than 2 channels).

author: boffin
author_rank: Unknown
timestamp: August 17, 2016, 06:26:27 am
content: Quote from: max100 on August 16, 2016, 05:54:49 pmWell, I'll be the unpopular person here, but for something as simple as stuff like that you need to ask yourself "What are you looking for with the scope?"If you just need to know if stuff is high or low, or even producing a PWM waveform, you can do all of that with a good meter such as the EXTECH EX330. About US$55. In addition to measuring voltage, current, resistance etc, it's got a good little frequency counter, with measurement for mark/space ratio for PWM (0-100%), which is probably going to satisfy most of what you need to do.The next step up is something like the nscope (nscope.org), or a digilent Analog Discovery (if you can find one used), or buy a used cathode ray scope for well under 100 quid, all that being said, it's pretty hard to go wrong with the Rigol if you do decide on a modern scope.but I would still argue that if you only have a limited budget thatExtech EX330(maybe *2) + Good Soldering Iron + Panavise + Reasonable Bench Power Supplyis a better buy thanRigol Scope + Bad Solder Iron + bad bench tools + no regulated/limited power supplyone or two good multimeters are going to be with you for likely the rest of your life. They're a great investment, and stepping up from 10quid to 50quid makes a hell of a difference.

author: CustomEngineerer
author_rank: Frequent Contributor
timestamp: August 17, 2016, 06:51:26 am
content: Quote from: Fungus on August 17, 2016, 05:55:54 amI know. Not that I've actually used one, but I have seen/heard about them. I posted because TAMHAN gave absolutely no reasons to back up his suggestion that OP should go for an old Lecroy. I wasn't trying to say the Lecroy is a good or a bad recommendation, just that throwing out a name with absolutely no reasons is honestly a pretty worthless comment. No offense to TAMHAN, but why should OP consider a Lecroy 9300 and Salae clone.

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 07:09:41 am
content: Quote from: CustomEngineerer on August 17, 2016, 06:51:26 am...or where you'd actually buy one, who sells the printer paper, where do you get floppy discs for the screenshots, what actually comes out of that strange "dispensing slot" above the screen, etc., etc.I stopped asking questions like "why?" a long time ago.Remember:Beauty is in the eye of the beholder.

author: JPortici
author_rank: Super Contributor
timestamp: August 17, 2016, 07:24:44 am
content: Quote from: rob77 on August 16, 2016, 08:49:11 pmand who said so, in this thread?now consider this: tool X has a feature that should be handy. however, it is not so handy to me to use the feature to the point that i prefer to (apparently) waste the time to take tool Y out of its box and set it updo you think that i consider -feature- in tool X a plus or a waste of resources?apply to any tool.i want tool that works how i want to. this tool doesn't, but saying it and suggesting alternatives apparently is against the accepted dogma

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 07:36:28 am
content: Quote from: JPortici on August 17, 2016, 07:24:44 amWe weren't recommending a 'scope foryou.

author: nctnico
author_rank: Super Contributor
timestamp: August 17, 2016, 07:44:53 am
content: Still when working with a microcontroller I'd go for a scope with protocol decoding AND 4 channels. Unfortunately decoding is crippled on the Rigol DS1000Z series; probably so Rigol's DS2000 and DS4000 series don't get too much competition from their lower end offerings.

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 08:00:00 am
content: Quote from: nctnico on August 17, 2016, 07:44:53 amIt seems to work...

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 08:21:22 am
content: If anybody has a suggestion for a 4 channel, 100Mhz DSO with serial decoding abilities for approx. $400 thatisn'tthe DS1054Z then please step up.Otherwise this is just devolving into the usual pointless, sour grapes, scope-waving thread.I'm with TheSteve:Quote from: TheSteve on August 16, 2016, 07:46:08 pm

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2016, 08:48:10 am
content: Quote from: max100 on August 16, 2016, 05:54:49 pmGeneral principle: structure your inplementation, integration and testing so that - as far as possible - you can use a multimeter LEDs and switches. That is a surprisingly effective discipline for many but not all purposes: it enforces doing things step-by-step. But eventually a scope and a signal generator will be necessary, particularly for analogue control loops.For sensors, servos, motors, control systems, it is unlikely that you will need a 100MHz scope. You may find it beneficial/necessary to have one with a particularly sensistive input, but at that point noise and interference will become important.For digital systems, a two-pronged strategy is necessary:first signal integrity; there's no point in looking at the digital signals if they are wrong due to crosstalk, ground bounce, reflections, noise etc. Thatrequiresa >=100MHz scope, which can be analogue or digitising.secondly digital content. This can be done with a scope or a logic analyser, whichever is more convenient. Even low-end logic analysers wll give you more channels (8/16/32) plus protocol decoding.Whether the extra channels are beneficial depends on the system under test, but they can beveryvaluable if you need to understand what the software is trying to do in real time. Useful technique: have the software write bits to an output port whenever it does something, e.g. FSM's current state or enter/exit a function.So, a 100MHz 1054Z is one way to skin your cat, but are others which may have some additional benefits.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 17, 2016, 09:13:40 am
content: Quote from: CustomEngineerer on August 17, 2016, 06:51:26 amFrankly, even I wouldn't recommend to buy a LeCroy 9300 scope to someone like the OP. Not that they were bad scopes (they were in fact the most advanced scopes when they were current back in the '90s), but even the last ones (9384) are now 19 years old, and the (by todays standard) slow processing and burn-in prone CRT doesn't make them very attractive when increasingly often you can get the much newer, a lot faster and physically smaller WaveRunner2 LT for similar money.Realistically, at $400, there isn't much choice if you want a 4ch scope that can be hacked to enable (woeful) serial decode. If you defer decoding to another device then the GW Instek GDS1054B is probably the better alternative (more mature, faster platform, better FFT but lacks serial decode) for roughly the same price.As to 2nd hand, $400 isn't really going to buy you a better scope as in that price class you usually only find overpriced analog boat anchors, old sampling scopes and real-time scopes with very low sampling rates and little memory. You can get some HP 54600 scopes which are nice but the ones in that price range usually have 2 channels and 200MSa/s sample rate. Same with LeCroy, you might find a working 9300 scope in that range but then it will be one of the early ones with 200MSa/s or so sample rate only which isn't great (the faster 9300s still fetch a lot more than $400).The 2nd hand scope market has often some great bargains but rarely in the $400 range.

author: borjam
author_rank: Unknown
timestamp: August 17, 2016, 09:29:33 am
content: Quote from: tggzzz on August 17, 2016, 08:48:10 amAn oscilloscope can be really useful to look at timings, for example. If your device is intended to be battery powered, it can be really useful to monitor consumption using an oscilloscope so that you can check the power consumption for each program "function" (I mean, reading this sensor, transmitting the value, etc). You can measure it directly (with a current probe or something like a µCurrent) or derive an indirect estimate by knowing at least how long does it take for your WiFi transmission to complete.Cheap oscilloscopes have dramatically lowered the bar to afford one. I've got an "upgraded" Rigol 1074Z and, despite its limitations, well, I am much better with it than without it!

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2016, 10:15:45 am
content: Quote from: borjam on August 17, 2016, 09:29:33 amAgreed.For "PSU" testing I use a low-speed (<=10MHz) digitising scope, e.g. for startup transients or with very slow sweep speeds like your use-case. It is one area where an analogue non-storage scope cannot be made to do the job. A 1054Z would, of course, be perfectly adequate for this.

author: JPortici
author_rank: Super Contributor
timestamp: August 17, 2016, 10:47:47 am
content: Quote from: Fungus on August 17, 2016, 07:36:28 amso the only valuable information should come from you and everybody with other experiences or opinions is a rigol basher and shouldn't be allowed to speak on the mattergod you are more of a buffoon with each post i read(i didn't want to go there but yeah, i did. peace out)

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 11:17:20 am
content: Quote from: JPortici on August 17, 2016, 10:47:47 amNope. If you have a sensible suggestion that fits the OPs budget then please post it.(crickets chirping)What you actually posted was this:Quote from: JPortici on August 17, 2016, 07:24:44 amNo explanation, no justification, just "it doesn't work the wayJPorticiwants it" (whatever that is).Quote from: JPortici on August 17, 2016, 07:24:44 amIndeed.PS: The word you want isn't "dogma", it's "pragmatism".

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 11:22:12 am
content: Quote from: Wuerstchenhund on August 17, 2016, 09:13:40 amThe GDS1054B also lacks a couple of other things: eg. 100MHz bandwidth.(Oh, right, you conveniently forgot that one...)But yeah,ifit turns out you need huge amounts of serial decoding you can get a $10 logic analyzer on eBay.I'll say it again:Quotenb. I added the extra "or without", just for you. The fact is though, there isn't an alternative 4 channel, 100MHz DSO evenwithoutserial decoding. The DS1054Z has serial decodingas well. It's double-icing on the cake.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 17, 2016, 11:47:47 am
content: Quote from: Fungus on August 17, 2016, 11:22:12 amTrue.QuoteI hope you don't want to imply I didn't mention bandwidth by purpose because if so it would present a pretty ugly and immature image of yourself.Also, you said 'a couple of other things'. We have lack of serial decode and (hacked) bandwidth. What else?

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 11:55:05 am
content: Quote from: Wuerstchenhund on August 17, 2016, 11:47:47 amIt has less memory and the display persistence is a bit poor but I'm not going to be childish and say "lacking" for those (unlike the people busy saying the DS1054Z serial decode is somehow useless, for example).What does itlackcompared to the DS1054Z? I'll say "Build quality"(not my words, Dave's - see his teardown video)And now I declare this thread truly descended into the usual pointless, sour grapes, scope-waving thread. Yawn.

author: nctnico
author_rank: Super Contributor
timestamp: August 17, 2016, 11:58:18 am
content: Quote from: Fungus on August 17, 2016, 08:21:22 amSince the OP didn't state a budget at all your point is moot. On the Rigol DS1000Z serial decoding is crippled, the UI seems to be slow, the samplerate is low, no really advanced features, memory shared between channels, etc. Besides that you have to hack the Rigol DS1050Z for the $400 to be a good deal which could be something the OP objects to. And what if Rigol decides to plug the hole in the next firmware update? All in all you still don't get what you don't pay for. Spending a bit more can gain a lot in neat features not found on the Rigol DS1000Z series. The GW Instek GDS2000E series have (for example) adjustable input filtering which can be usefull for looking at PWM signals with the modulation frequency removed.

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 12:04:46 pm
content: Quote from: nctnico on August 17, 2016, 11:58:18 amIn what way?Quote from: nctnico on August 17, 2016, 11:58:18 amHe didn't mention he wants serial decoding either, but that isn't stopping you from laboring it.Quote from: nctnico on August 17, 2016, 11:58:18 amWeirdly enough: He actuallydidmention that one...

author: nctnico
author_rank: Super Contributor
timestamp: August 17, 2016, 12:06:29 pm
content: Quote from: Fungus on August 17, 2016, 12:04:46 pmYou just won the tripple face palm award:It only decodes what is on screen which is utterly utterly utterly useless. Now go and wash your hands because they must be very dirty trying to polish a turd.

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 12:11:53 pm
content: Quote from: nctnico on August 17, 2016, 12:06:29 pmMany thousands of people have found it useful - including me!Maybe we all need our realities adjusting by nctnico. We onlythoughtit was useful.

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2016, 12:15:48 pm
content: Quote from: nctnico on August 17, 2016, 12:06:29 pmThe question then becomes "how much can you get on a screen and decode". Any rules of thumb?If it is only a few bytes, then the benefit of such decoding would be limited to "have I transmitted my message as expected" or "what should I have received". That's useful for low-level system integration.For debugging a complete system's operation, it is usually necessary to capture a sequence of short messages spread over a potentially long time. That's where logic analysers and printf statements are useful - and scopes aren't.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 17, 2016, 12:16:35 pm
content: Quote from: Fungus on August 17, 2016, 11:55:05 amFair enough, although 10Mpts is plenty for a scope with a low sample rate of 1GSa/s or less.Hasn't the persistence display been improved with a firmware update recently?QuoteI haven't tried serial decode on a DS1000z myself but wasn't it limited to decoding what's on the display? If so then this is a serious limitation. Certainly not useless as it still can decode something, but if you need to actually work with the decoded data (i.e. scroll through sequences) then you'll have difficulties doing this with displayed data only.QuoteI'm not sure I'd agree with Dave here. And besides, wasn't this a pre-production scope (or was that another GWI scope)?But since you mention build quality, what about design quality?https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/I don't believe you'll find a similar flaw in the GWI, and even though Rigol seems to have plastered it over with a firmware patch as I understand it the hardware issue is still there.QuoteMaybe, but if so then you can most certainly take some credit for that

author: nctnico
author_rank: Super Contributor
timestamp: August 17, 2016, 12:23:48 pm
content: Quote from: tggzzz on August 17, 2016, 12:15:48 pmUnfortunately printfs aren't always available especially if you are diagnosing a black box. Try to find an intermittent I2C problem with a scope which only decodes what is on screen. You'll need to zoom in on the problem area but as soon as you scroll the I2C start outside the screen the decoding will be gone. Using a scope for protocol problems is very handy and maybe even more usefull than a logic analyser because a scope with decoding also shows analog domain problems and usually lets you save the messages to a text file so you can process/filter them on a PC.

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 12:29:48 pm
content: Quote from: Wuerstchenhund on August 17, 2016, 12:16:35 pmYes it "only" shows what's on the display, but guess what: The display can be zoomed and scrolled.Turn the memory size to max (24Mb), optionally set the trigger for a particular sequence of data, do a single shot capture and you'll have many screenfulls of data. You can then zoom/scroll to view the contents (choose from ASCII, HEX, decimal...)Imperfect? Sure.Worse than a dedicated logic analyzer for long transactions? No argument there.But it's a loooooong way from "utterly utterly utterly useless (facepalm)(facepalm)(facepalm)".

author: madires
author_rank: Super Contributor
timestamp: August 17, 2016, 12:44:40 pm
content: I'd suggest either the DS1054Z or an used 2-ch scope plus an USB logic analyzer, Saleae for example. If you're interested more in the digital signals than in analog stuff, go for the latter.

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 12:59:14 pm
content: Quote from: Wuerstchenhund on August 17, 2016, 12:16:35 pmExpert plasterer, perfect paint job => zero measurable effect on screen.Lets call it quits...

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 01:10:51 pm
content: Quote from: nctnico on August 17, 2016, 12:23:48 pmOK, but:a) None of that qualifies the DS1054Z as 'useless' - you can see short transactions perfectly and check if the pullups are correct (ie. everything you need to find most I2C problems).b) How much does a 'scope that meets nctnico standards cost? What model?c) How does option (b)'s I2C decode compare to a $10 USB logic analyzer+PC?

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2016, 02:45:25 pm
content: Quote from: nctnico on August 17, 2016, 12:23:48 pmSure; there are no silver bullets, all tools have their limitations, frequently there is more than one tool that can do a job, and with imagination you can often use a tool outside its nominal application domain. (E.g. using my shiny old TDR as a 60ps risetime source for measuring scope transient response)Nonetheless, my statement stands. And anything other than a completely "toy" LA should be able to capture and decode far more than a scope,andupload it to a PC for postprocessing. external clock, or only store sample on rising edge of a signal, or only store a sample when X and Y true.

author: nctnico
author_rank: Super Contributor
timestamp: August 17, 2016, 03:05:40 pm
content: Define non-toy logic analyser... IMHO you quickly arrive at the Tektronix or Agilent logic analysis mainframes and even the portable ones weigh around 10kg. Traditionally these don't come with protocol decoding or triggering either. Maybe one of the more advanced USB logic analysers can do what you describe (some kind of segmented recording would be nice but chances are time relation is lost) but all in all using a scope/MSO is just way easier in most cases when it comes to protocol troubleshooting.

author: rstofer
author_rank: Super Contributor
timestamp: August 17, 2016, 03:18:44 pm
content: Quote from: tggzzz on August 17, 2016, 12:15:48 pmFor my purposes, at the moment, the maximum SPI packet I actually want to decode is 9 bytes and I can easily decode 12 bytes across the screen. I am only looking at framing and a couple of prototypical transactions. Once the driver is working, CPOL and CPHA are correct, I receive back what I expect having transmitted some command, that's all I need. The longer transactions (entire TCP packets) will use the same driver and I don't expect to have to decode them. Worst case, I need to look at the first few bytes to make sure I sent the data to the correct memory block. I have no reason to decode the entire packet and, even if I could, it would be a complete waste of time to paw through it. Wireshark comes to mind...There are probably ways to cheat the decoding of long streams. Maybe dump the CS' signal for framing and just set an output bit just ahead of the region of interest and sync on that. The decoder just wants to see something that starts a frame but it has no way of knowing that the packet started days ago. I2C is different and a lot more difficult to work with.To get 100 MHz and 4 channels with the Instek GDS2000 series, as previously suggested, you would need to consider the GDS2104A - a pretty nice scope at 3-1/2 times the price. Or, we could scale up to Keysight and move into the $16k or even $25 arena. Those scopes are way better! There simply has to be a concept of 'utility' or, more properly, 'marginal utility'. How much is it worth to get an incrementally better scope?Good enough is just that! This is just a hobby, one of several, and not even the most expensive. Living on a fixed income means being just a little careful with where I spend my money. The DS1054Z will meet my simple needs for a very long time.

author: rstofer
author_rank: Super Contributor
timestamp: August 17, 2016, 03:30:11 pm
content: Here's a screen shot of the 12 byte SPI image. Only 9 bytes are in the first frame.Ignore the ringing; considering the way I have the wires dangling off the breadboard, it is no surprise. Nor of any concern...

author: Fungus
author_rank: Super Contributor
timestamp: August 17, 2016, 04:39:46 pm
content: Quote from: rstofer on August 17, 2016, 03:30:11 pmLooks useful - to a buffoon like me, at least.

author: nctnico
author_rank: Super Contributor
timestamp: August 17, 2016, 05:24:18 pm
content: Quote from: rstofer on August 17, 2016, 03:30:11 pmNow try and look at the clock versus data timing for the 6th bit in the 8th byte. You can't see things like that on the timescale your screendump is at. If you need to look at an I2C, CAN or SPI bus then you are likely dealing with a problem in the analog domain (signal levels or timing) and to see such problems you need to look at the bit level of a message which means zooming in.

author: rstofer
author_rank: Super Contributor
timestamp: August 17, 2016, 06:01:19 pm
content: Quote from: nctnico on August 17, 2016, 05:24:18 pmGiven that the SPI timing is all generated by the LPC1768, why would the 6th bit of the 8th byte be any different than any other bit? The operation is atomic so even if an interrupt came along mid-byte, nothing would change. Yes, the inter-byte timing might change but nothing within the byte.OK, maybe the problem is with the slave device. Even then, I can see the 6th bit of the 8th byte (or even the 10th repetition of the 6th bit of the 8th byte if I don't mind twiddling the knob to scroll through) but what I can't do is decode that particular byte because I don't have the CS' edge on the screen. And I'm not even sure I can't decode it.So I manually set the scope to use the maximum storage size (6 Mb/channel) and I captured a long sequence of packets (while(1) loop). Each packet itself is less than 10 bytes. It seems I can scroll through the entire memory and the decoding stays on the screen. And I keep scrolling and scrolling and scrolling... It just keeps decoding.I need to think about this! I have many packets, far more than a single screen so I have multiple start conditions and one is always on the screen but I am not losing the decoding of a packet whose start condition has just scrolled off the screen.I got tired of twiddling the knob in the mid-400 us range. Each clock is 1 us so I'm pretty far into the buffer. And I'm still getting decoding. I'm not sure I know what I think I know about decoding!

author: rstofer
author_rank: Super Contributor
timestamp: August 17, 2016, 06:09:38 pm
content: Quote from: Fungus on August 17, 2016, 05:36:27 pmOK, now I know where the defect is in the DS1054Z. I finally found it! It has too many features! ZOOM - are you kidding me? How many years is it going to take me to learn all of the features in a low end digital scope. Thank goodness I didn't buy a high end scope!I never had to worry about this stuff with my old analog scope. What I saw was what I got. Now I can store the trace, expand it at will, slide traces up over other traces, get programmatic measurements and it's all in color.Actually, I knew ZOOM was there, I just haven't had an opportunity to use it. Pretty slick!

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2016, 08:35:16 pm
content: Quote from: nctnico on August 17, 2016, 03:05:40 pmYou can infer it from the footnote in my post - the one immediately before your response.Since you missed it somehow, a "non-toy" LA has " external clock, or only store sample on rising edge of a signal, or only store a sample when X and Y true."Thecanonicaltoy LA is one that has an internal 100MHz clock that is asynchronius w.r.t. the UUT.QuoteThat depends entirely on what you are trying observe. See my earlier posting for examples where it sufficient and where it is not.

author: lem_ix
author_rank: Regular Contributor
timestamp: August 17, 2016, 08:43:01 pm
content: The rigol ds1054z seems like a very powerful scope for a beginner, I'm pretty sure you won't outgrow it any time soon. It can decode your basic serial protocols, also has enough bandwidth for what you're planning to do with it.

author: nctnico
author_rank: Super Contributor
timestamp: August 17, 2016, 09:41:46 pm
content: Quote from: tggzzz on August 17, 2016, 08:35:16 pmI was trying to make you name some specific devicesQuoteThat is a rather generic statement. If you attack a (suspected) protocol problem by connecting a logic analyser before checking the analog domain you might end up staring at a screen which makes no sense at all for days (yes, that happens to people for real!). Form that point: if you already have analog channels connected it is much easier to enable decoding on a scope than disconnecting the scope and connecting a logic analyser (and set it up, etc). Sure you can make-do without and use alternative ways but the easier life is the better.

author: rstofer
author_rank: Super Contributor
timestamp: August 17, 2016, 10:08:40 pm
content: Quote from: tggzzz on August 17, 2016, 08:35:16 pmAbsolutely, a logic analyzer must accept an external clock. It should also have multiple layers of triggers where each layer is a logic equation including all of the bits on the display. "If this pattern, followed by that pattern, followed by this other pattern, trigger". Even the Sump logic analyzer can do this kind of thing.http://www.sump.org/projects/analyzer/client/See the second screen image "...complex trigger": There are 4 levels of 32 bits. Pretty neat!Note that for state analysis, the maximum clock rate is slowed down to 50 MHz. It's usually 100 MHz for 32 channels or 200 MHz for 16 channels.

author: tggzzz
author_rank: Super Contributor
timestamp: August 18, 2016, 12:00:13 am
content: Quote from: nctnico on August 17, 2016, 09:41:46 pmSigh; this is becoming tediously repetitious. See what I wrote earlier in this thread:https://www.eevblog.com/forum/testgear/oscilloscope-for-arduinoraspberry-pi-projects-2-or-4-channel-critical-specs/msg1006185/#msg1006185QuoteFor a subset ofsystemintegration and debugging problems (e.g. a serial bus), maybe. But if the problem might be correlated with processor load, or 99.9 percentile latency, or eventsequences, etc etc etc, then an LAwillbe necessary.It is possible to use a hammer to insert screws with a hammer. Often that is very convenient. But having a screwdriver in your toolkit (and knowing when to use it) is beneficial.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 18, 2016, 08:44:17 am
content: Hello,sorry for starting a "farty party" here - did not intend to cause grief.To be honest: I dislike small oscilloscopes, probably due to a horror experience in past militia service. if I can pick up a scope and throw it easily, it is not for me. Plus, the insane measuring capabilities of the LeCroy really make keeping an eye on things easy - think frequency changes, for example.To answer the questions:x) Re Paper: stay tuned. I am currently sniffing out some sourcesx) Re floppy disk: same.Re the serial decoding: this is, of course, a topic one can fight for hours. But I tend to do rather "big" things, which is why I - um - always want to see my code next to the logic output. Could be Dementia, I know....

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 18, 2016, 09:40:14 am
content: Quote from: TAMHAN on August 18, 2016, 08:44:17 amI don't think you caused grief. Some discussions have a tendency to veer off, but that's natural in a forum like this.QuoteI have nothing against lightweight scopes but I agree that there's a limit, which is when it's so light that pressing a button moves the whole scope.And with larger scopes you usually get larger screens, which can be a big benefit. Many of the entry-level scopes come with small screens which can become very cramped when using all channels and doing other stuff.QuoteNo argument here. The measurement capabilities of entry-level scopes are generally very simple and limited.QuoteI wouldn't bother with the printer, it's about the same quality as a cash register receipt (i.e. poor), and even less so with the floppy.If your scope has the PCMCIA option (a hardware option on the 9300 Series, standard on later scopes) is much more useful as if you enable the HDD or HD01 software option then you can use a cheap PCMCIA to Compact Flash adapter and a small CF card and use that as a removable "hard disk" to store screenshots, measurement data and settings. Most cards up to 2GB work, although the single partition is limited to 512MB (which is still plenty enough for data and screenshots). After you've done you just put the card in a card reader and voila, you got a simple and reliable medium for transferring data.

author: Fungus
author_rank: Super Contributor
timestamp: August 18, 2016, 11:29:54 am
content: Quote from: TAMHAN on August 18, 2016, 08:44:17 amDid you find out what comes out of the mystery dispensing slot?(or goes in...the photo is inconclusive)

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 18, 2016, 12:27:10 pm
content: Quote from: Fungus on August 18, 2016, 11:29:54 amThat is the PCMCIA slot I wrote about.

author: Karel
author_rank: Super Contributor
timestamp: August 18, 2016, 12:36:44 pm
content: Quote from: nctnico on August 17, 2016, 11:58:18 amDon't worry, even a non-hacked DS1054Z is still unbeaten for price/performance ratio.

author: max100
author_rank: Newbie
timestamp: August 21, 2016, 01:44:47 pm
content: Many thanks to everyone for all the informative advice.

author: tggzzz
author_rank: Super Contributor
timestamp: August 21, 2016, 03:29:57 pm
content: Quote from: Karel on August 18, 2016, 12:36:44 pmWho cares what the price/performance ratio ofanythingis? That's something marketeers dream up to convince PHBs (and preferably "upsell" to them!).What matters is:does it do whatIneed it to do inmyapplication?canIafford it?is there a significantly cheaper choice that will fulfilmyneeds?

author: Karel
author_rank: Super Contributor
timestamp: August 21, 2016, 03:36:37 pm
content: Quote from: tggzzz on August 21, 2016, 03:29:57 pmWrong. What really matters for hobbyists is this:"I want the best oscilloscope there is, but I can't afford it. So, what is the best oscilloscope I can buy with a given budget?"

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 21, 2016, 04:24:34 pm
content: Hello,to be honest: overbuying is not true in every case.At least for me, multiple criteria need to be met - one of which is the way the whole thing looks and feels. I am just a sucker for the old Iwatsu Combiscopes - if you dim the light, they even become photogenic:EDIT: One more thing, as I have it handy. Here is a screenshot of my Salae Clone decoding something. IMHO, it beats the crap out of any scope as you can zoom in and out as you see fit.Regarding the LeCroy: if you send me a photo of the "slot" to tamhan at tamoggemon dot com, I will look up what it does.

author: max100
author_rank: Newbie
timestamp: August 21, 2016, 04:31:45 pm
content: I can only speak for this hobbyist - I just want the most economical solution and don't want to make the mistake of buying an inadequate instrument that I subsequently need to replace because of inadequate research.I am learning so I am unsure of the needs that may develop like more channels, higher bandwidth etc. The responses in this thread are very helpful and I have found the advice on Logic Analyzers very useful too. Thanks all!

author: Fungus
author_rank: Super Contributor
timestamp: August 21, 2016, 05:05:25 pm
content: Quote from: tggzzz on August 21, 2016, 03:29:57 pmSure... so long as you know what your "needs" are for the next 5 years or so.(or were you planning to throw it away after this application is done...)

author: nctnico
author_rank: Super Contributor
timestamp: August 21, 2016, 05:20:33 pm
content: Don't expect to buy any equipment which last a lifetime (unless you are 110 years old). I upgrade my equipment every few years because technology keeps moving on fast.

author: Karel
author_rank: Super Contributor
timestamp: August 21, 2016, 05:35:09 pm
content: Quote from: nctnico on August 21, 2016, 05:20:33 pmAre you talking about your work environment or at home (hobbyist environment)?In general, on this forum, at least to me, it's not always clear if people talking about professional or hobbyist usage...

author: nctnico
author_rank: Super Contributor
timestamp: August 21, 2016, 05:55:17 pm
content: Quote from: Karel on August 21, 2016, 05:35:09 pmI make a living using my equipment so it is professional use but then again I have always spend money on test equipment (even when I was studying).

author: stj
author_rank: Super Contributor
timestamp: August 21, 2016, 06:07:27 pm
content: a lot of people posting irelevent rubish and ignoring the question - it's related to robotics.those 4 channels will be a must if your working with stepper motors that "lock" or vibrate / hum.and also for monitoring regular motors that have quadrature-encoded feedback.scopes are not intended for grabbing and storing huge serial streams - get the right tool for the job if that's what you need to do.a $5 8channel 24MHz usb LA from china will sort that need.

author: rx8pilot
author_rank: Super Contributor
timestamp: August 21, 2016, 06:17:36 pm
content: Quote from: Karel on August 21, 2016, 05:35:09 pmThere is a big gray area there. When I was purely an enthusiast, I still purchased the professional equipment for whatever I was doing. Maybe older, used, fixer-upper, but generally pro level. I never had much because of it but in that small area of interest - I was able to operate like a pro. For the most part - I really hated doing all the work to solve a problem or make a project work only to spend the majority of that time fiddling with tools that were marginal. If I was going to fail, I want it to be because I did not figure out the problem, not because I could not effectively measure the solution. I tailored my projects to the availability of the equipment I had available and my ability to use the instruments.As I transitioned to professional work, I have a similar desire - SOLVE THE PROBLEM without being distracted by the limitations of the available equipment. I regularly buy test equipment that I don't really know how to use, or at least not well. That learning opportunity moves my skill level up just by learning how to measure something and why it needs to be measured.For me, getting to the title topic, I would look at a cheap 4ch scope for basic signal integrity measurements, a Saleae LA for timing on long sequences, and a Beagle for decoding. They can be purchased at different times as money becomes available and the three are used for different things that add up to a complete measurement. This is how I was setup until recently - Old Tek scope, Saleae, and Beagle and was able to get through some complex projects that I could not have done practically without all three things that were purchased over time (because I was VERY short on cash).The scope is definitely the first thing in line, and having one that allows decoding is great. Keep in mind that the fancy new Keysight scope I recently won still di not replace the Total Phase Beagle for I2C and SPI when I am looking at the bigger picture issues. I would not get a scope without 4ch, especially for the stated task.

author: nctnico
author_rank: Super Contributor
timestamp: August 21, 2016, 06:34:23 pm
content: Quote from: stj on August 21, 2016, 06:07:27 pmAn oscilloscope is the perfect tool for that job (analysing serial streams) because a lot of problems are in the analog domain which a logic analyser won't show at all. Unfortunately sometimes that means capturing lots of messages and sorting through them to find an intermittant problem.

author: rx8pilot
author_rank: Super Contributor
timestamp: August 21, 2016, 06:42:17 pm
content: Quote from: nctnico on August 21, 2016, 06:34:23 pmI use the scope for close looks at errors. They can be analog in nature or some other source of glitches. I use the Beagle to record and analyze long streams that allow me to see errors from logic in the programming of the system not physical layer errors. Those errors are hard to see up close as the scope see things and easier to see from a distance. At least with my designs anyway.

author: lem_ix
author_rank: Regular Contributor
timestamp: August 21, 2016, 09:22:28 pm
content: For example the two robots in the back of this video were made with an occasional use of a very crappy instek scope ( no decode, grading, etc, think it was a gds-1000) and cheap Chinese dmms.Both have a raspberry pi connected to several sub boards which control actuators, sensors,motion, etc by modbus/rs485 and are autonomous, have collision detection and path finding. The ds1054z is capable of viewing pretty much anything in there, lacking maybe rs485 decoding? Don't worry too much about it and get a good C book, you'll spend most of your time on that.

author: max100
author_rank: Newbie
timestamp: August 21, 2016, 11:47:26 pm
content: Quote from: stj on August 21, 2016, 06:07:27 pmThat is the first step I will take thanks to the advice in this thread.But what software do these use? Investigating LAs this week I get the impression that Saleae has found a way to block the use of its s/w by other manufacturers' devices. There is an open source project called sigrock.org ... Is that good? All the Chinese LAs I have come across rely on 3rd party s/w.

author: stj
author_rank: Super Contributor
timestamp: August 22, 2016, 01:08:00 am
content: you can use Sigrokhttp://sigrok.org/or the saleae software, if you dont use the latest.*or* replace the eeprom in the LA with a microchip brand 24LC00(dont forget to copy the contents)'

author: max100
author_rank: Newbie
timestamp: August 22, 2016, 01:56:54 am
content: Thanks,Is Sigrok good?How do you get hold of the last open Saleae s/w?

author: stj
author_rank: Super Contributor
timestamp: August 22, 2016, 02:11:30 am
content: latest:http://support.saleae.com/hc/en-us/articles/210245583-saleae-logic-beta-softwareolder:http://support.saleae.com/hc/en-us/articles/210245603-Older-Saleae-Logic-Beta-Downloads

author: Fungus
author_rank: Super Contributor
timestamp: August 22, 2016, 04:08:31 am
content: Quote from: max100 on August 21, 2016, 11:47:26 pmYep, that's why they're so cheap - no programmer's salaries to pay (or offices, or chairs...)Quote from: max100 on August 22, 2016, 01:56:54 amNot as good as saleae.https://sigrok.org/wiki/PulseView

author: max100
author_rank: Newbie
timestamp: August 22, 2016, 05:53:59 am
content: Quote from: max100 on August 22, 2016, 01:56:54 amNot as good as saleae.https://sigrok.org/wiki/PulseViewFunctionally not as good? If so in what way?I can live without a fancy user interface.

author: Fungus
author_rank: Super Contributor
timestamp: August 22, 2016, 08:32:46 am
content: Quote from: max100 on August 22, 2016, 05:53:59 amYou're the only person who knows what you want. See the websites for manuals, documentation, etc.At a screenshot level it's this:vs. this:

author: Fungus
author_rank: Super Contributor
timestamp: August 22, 2016, 09:23:04 am
content: Quote from: TAMHAN on August 18, 2016, 08:44:17 amYou once threw a scope and it wasn't heavy enough? Now you have nightmares?Details, man, details...

author: max100
author_rank: Newbie
timestamp: August 22, 2016, 11:15:50 am
content: Quote from: Fungus on August 22, 2016, 08:32:46 amHave you used them or is your opinion based on the user interface screenshots?

author: Fungus
author_rank: Super Contributor
timestamp: August 22, 2016, 11:42:42 am
content: Quote from: max100 on August 22, 2016, 11:15:50 amSaleae is nicer, more complete.Sigrock does the job.More info here:https://encrypted.google.com/search?q=sigrock#q=sigrok&tbm=vid

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 22, 2016, 11:48:48 am
content: Quote from: Fungus on August 22, 2016, 09:23:04 amLet us just say: higher-ranking girly with extra sexy feet (sexy-meter:even in highest setting) and a very beepy and crashy scope from an unnamed manufacturer. And no, I didnt throw it. Just hated it.But back to the main topic: one more very important feature, IMHO, is Peak Detect. I linked my video in the page before...and tonight just thought that this kind of problem is likely to also happen in robotics.P.S. That PulseView screenshot looks better than Salae TBPH, at least for me. I dislike Salaes "farty-party" user interface.

author: Fungus
author_rank: Super Contributor
timestamp: August 22, 2016, 11:52:37 am
content: Quote from: TAMHAN on August 22, 2016, 11:48:48 amMe too.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 22, 2016, 12:06:31 pm
content: Sadly, my Chinese clone is said to show preference to Salae ;(

author: madires
author_rank: Super Contributor
timestamp: August 22, 2016, 01:06:01 pm
content: Quote from: TAMHAN on August 22, 2016, 11:48:48 amI fully agree. Salae's UI looks too cool to be useable, more like a fancy gadget for kids or a hacker movie. PulseView on the other hand focuses on the data, which I'd consider a tool. When I have to look hard to see the data, the UI is done wrong.

author: Fungus
author_rank: Super Contributor
timestamp: August 22, 2016, 01:32:02 pm
content: Quote from: madires on August 22, 2016, 01:06:01 pmPale grey on slightly darker grey is fashionable. You see it in every modern UI.PulseView looks like it was written before 2010.

author: rf-loop
author_rank: Super Contributor
timestamp: August 22, 2016, 04:55:00 pm
content: Quote from: Fungus on August 22, 2016, 01:32:02 pmModern is not synonym for better or good.

author: tggzzz
author_rank: Super Contributor
timestamp: August 22, 2016, 05:18:54 pm
content: Quote from: rf-loop on August 22, 2016, 04:55:00 pmVery true.While I don't like skeuomorphic GUIs, the modern "flat" design has gone to the opposite extreme. It has regressed to the middle-80s style where it can be difficult to determine whether a widget (e.g. tab) is activated, or even whether something is a pressable widget! I remember when Motif introduced the "3D" effect, and how much easier it made using GUIs.One simple example: my ISP has a web page with two tabs, one black and one white. Guess which tab is already visible, and which can be pressed to show the other information. With even a minimal 3D cue, it is obvious.

author: rstofer
author_rank: Super Contributor
timestamp: August 23, 2016, 12:41:20 am
content: Quote from: Fungus on August 22, 2016, 11:52:37 amI went looking at the Salae Pro 16 (it is recommended around here from time to time) and I have already installed Sigrok for one of the uber cheap LAs. The Salae doesn't seem to support state analysis and, for me, that is fatal. I'm pretty sure the cheap LA I have hooked to Sigrok doesn't support it either and I have no idea whether the software itself supports it.State analysis, to me, is the most important capability. I may not use it every single time but many times I want to know the state of signals at the actual clock edge, not some sampled clock.The Salae software, AFAICT, doesn't have much of a triggering system. First of all, I want 32 channels. Ignoring that, I want a staged trigger such that I can form 4 stages (layers) of trigger logic states. See this pattern, followed by that pattern, followed by another pattern, followed, finally, by the last pattern: trigger now! I should be able to include or exclude all bits, invert all bits and form AND equations. I don't see it in the Salae documentation and I don't think I'll find it in the Sigrok stuff either.Some of these logic analyzers aren't analyzers at all. They are just binary scopes sampled at some low rate with no timing relationship to the device under test.All that said, the Salae software is pretty polished. That's easy when they aren't trying to interface to hundreds of different devices. Sigrok has quite a list of compatible pieces of gear.

author: stj
author_rank: Super Contributor
timestamp: August 23, 2016, 01:15:06 am
content: if you want a real clock, and not just a 33rd channel, you probably need to look at something like a sump.http://www.sump.org/projects/analyzer/

author: rstofer
author_rank: Super Contributor
timestamp: August 23, 2016, 04:03:21 am
content: Quote from: stj on August 23, 2016, 01:15:06 amActually, I have the Sump logic analyzer. If you search the site, you will probably see where I contributed a level shifter design.There are a couple of things I don't care for: First, I don't have it 'packaged' so it lays around my bench like another project. Second, i'm not stoked about Java and, more particularly, having to find the 'look and feel' library and the RXTX library. About 3 Java updates back, the GUI quick working and I have never gotten it working again. My fault, I just haven't spent the time it takes to get it working. I'm sure somebody has already figured it out.That LA is a really sweet unit for the cost. The original design for the Spartan 3 Starter Board was a blessing when I was working on my 1130 project because it also used the Starter Board. I'm not sure what boards are currently supported but it does talk about the issue on the site. The Starter Board is no longer available.

author: Rick Law
author_rank: Super Contributor
timestamp: August 23, 2016, 04:28:31 am
content: Quote from: max100 on August 16, 2016, 05:54:49 pmQuote from: max100 on August 21, 2016, 04:31:45 pmI am a fellow hobbyist, so my opinion is definitely NOT an expert's opinion. But having the "engine starting" not so long ago, I remember how it was like. The discussions about which scope is useful/good are no doubt very valuable. But I suggest perhaps you should see what problems stand in your way first.If I am to say: to really do electronics right, you should learn calculus first - you (or I should say, most) would not get started in electronics. No doubt calculus is both important and enlightening in solving many electronic problems. But you don't need that just to play with Arduinos/Raspberry.At the get-go, I saw all those candies and I want them. I ran in circles at the starting-gate. I eventually just got moving with a low cost DMM, then later added a low cost Scope. At the get-go, I wanted to have a 100,000 count DMM, but it turns out I don't need it. I wanted to have a 100mhz 1meg datapoint scope. Turns out in my case I rarely use a scope... I still want a 100,000 count+ DMM, but I don't need it to get started. I still like a 400Mhz scope, but I don't need it to get started..Don't worry too much about having to replace your equipment. By the time you learn enough to need a better DMM or a better Scope, there will be far better choices (performance) products then. You also would be much better equipped to find one much more suitable for your need. Besides, there is a good chance you may make newbie mistakes that even the very best equipment may not survive. So top shelf stuff may not be best for a new-newbie.The trouble with a Lamborghini is, you really don't want to learn how to drive with it.When you get to the point of doing the upgrade, the old/cheap stuff that you used to learn with will always have a home. A second scope or a second DMM (low cost starter) will always have a use.Again, just a fellow novice merely a steps or two ahead of you - trying to share what I know.Rick

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: August 23, 2016, 06:37:42 am
content: Quote from: Rick Law on August 23, 2016, 04:28:31 am+1And not just calculus, also a general understanding of the basic physics and math behind it (i.e. that all waveforms are made up of multiple sine waves at various frequencies).

author: Rick Law
author_rank: Super Contributor
timestamp: August 23, 2016, 07:34:17 pm
content: Quote from: Wuerstchenhund on August 23, 2016, 06:37:42 amAbsolutely - Basic Physics and basic calculus are indispensable in understanding electronics and many other things. Even some MBA programs requires calculus. Their importance can not be overstated.It had been posited (by a TV documentary) that it was Albert Speer's Engineering skills that got him off the noose in Nuremberg - the only one in Hitler's inner circle that escaped the noose. He worked it like an engineering problem: find out what the customer (judges) want, and present his case accordingly. He shown remorse and highlighted his own resistance to Hitler's instructions got him 20 years instead of the noose.Andy Grove, an Engineer and one of the most successful Intel-CEOs : "a strategicinflection pointis a time in the life of business when its fundamentals are about to change..." He didn't say where "inflection point" came into his mind, but those of us who had calculus has no doubt where he got it.However, if one must have calculus before electronics, not so many would get started. I was/am justencouraging the OP to jump-inget get his hair wet first. In the year that the OP spins up, newer scopes will come in on-line. Nice equipment is of course nice, but as I said, "The trouble with a Lamborghini is, you really don't want to learn how to drive with it."