About a logic analyser  - Page 1
Forum section: electronics / beginners

author: Microcode
author_rank: Newbie
timestamp: August 09, 2017, 08:24:58 pm
content: Hi everybody !I'm moving my very first steps in digital electronics. Up to now I have simply used LED to check logical states, but now I'm looking for a method a bit smarter. Googling, I have just bumped into in a cheap toy logic analyser ARM FPGA M100. I have understood that it draws, on the computer screen, a time vs state plot of the circuit's monitored points. Please, con you confirm or disprove that ?Thanks for your replies ! Have a great day !

author: Pseudobyte
author_rank: Frequent Contributor
timestamp: August 09, 2017, 08:33:48 pm
content: A good option would be anything that is compatible with sigrok.https://sigrok.org/wiki/Supported_hardwaregreat tool! You can also use sigrok with some oscilloscopes.

author: daybyter
author_rank: Frequent Contributor
timestamp: August 09, 2017, 10:40:19 pm
content: I think, you can find such an LA at ebay.com or aliexpress for under 10$ ?

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 10, 2017, 03:29:48 am
content: Look for Saleae clones and be sure to use them with the Sigrok software. Do not download the software from the Saleae site. Those logic analysers work pretty well, especially considering their price.If you ever have some money to spare, consider buying a real Saleae. Those have a few options that are pretty neat.

author: Microcode
author_rank: Newbie
timestamp: August 10, 2017, 05:56:56 am
content: Thanks for replyes !"A good option would be anything that is compatible with sigrok."Great hint ! I'm looking for ..."I think, you can find such an LA at ebay.com or aliexpress for under 10$ ?"I found it at Amazon"If you ever have some money to spare, consider buying a real Saleae. Those have a few options that are pretty neat."Unfortunately, it lies out of my present budget. But I will keep my eyes on it."Do not download the software from the Saleae site."Is it flawed ?

author: Kalvin
author_rank: Super Contributor
timestamp: August 10, 2017, 09:26:05 am
content: Quote from: Microcode on August 10, 2017, 05:56:56 amUsing a chinese clone with the official Saleae software is not ethically a good thing. Saleae has put a lot of effort and resources to develop and support their fine hardware and software, so using a cloned hardware with their software is not fair although it may be possible.

author: Zero999
author_rank: Super Contributor
timestamp: August 10, 2017, 10:46:07 am
content: Quote from: Kalvin on August 10, 2017, 09:26:05 amEthics are an interesting thing. Some would argue that overcharging (beyond recouping development and manufacturing costs) for hardware and getting it made low wage country with little labour protection laws, is also unethical but I don't know whether this is the case or not here.A more relevant question is whether it's legal to use said software, with a third party hardware? Does the licence agreement contain a clause saying it is only to be used with official Saleae hardware? If not, they clearly don't mind you using it with third party hardware, so there's no ethical question to answer. If there is, then there it clearly is illegal to use the software with a clone.

author: alm
author_rank: Super Contributor
timestamp: August 10, 2017, 11:09:09 am
content: Quote from: Hero999 on August 10, 2017, 10:46:07 amThey are charging for hardware + software (+ support). Whether you think this is worth the money over Sigrok/PulseView + cheap FX2 board is up to you. At least a couple of years ago, production was pretty much all in the US. They even bought their own pick & place machine at some point.Quote from: Hero999 on August 10, 2017, 10:46:07 amFrom the license of Logic 1.2.12:QuoteAnd they definitelymindthe clones.

author: abraxa
author_rank: Frequent Contributor
timestamp: August 10, 2017, 11:28:21 am
content: As usual when the issue comes up, I'd like to provide an alternative point of view regarding those "clones":https://www.eevblog.com/forum/beginners/new-oscilloscope/msg1191802/#msg1191802In essence, those devices "clone" parts of a development kit from Cypress. They're really just breakout boards. Saleae can whine all they want, they knew exactly that they were writing software for a development kit, without any kind of protection in place. It may not be legal that people use their software without purchasing the hardware dongle (which fails being a dongle) but they are partly to blame themselves.So like I said, when you purchase a $10 FX2LP eval board from China, it only turns into a "Saleae Logic clone" when used with the Saleae Logic software. When used with sigrok, it's not a Saleae Logic, it's a generic FX2LP breakout board that we use with our own firmware. Saleae did not spend any significant effort on hardware or firmware. That has all already been provided by Cypress.

author: frenky
author_rank: Unknown
timestamp: August 10, 2017, 11:36:01 am
content: In latest versions of Saleae hardware they have put some extra characters into eeprom so they can check in software for those characters...This way they tried to prevent users from using clones with Saleae software.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 10, 2017, 11:38:19 pm
content: Quote from: Hero999 on August 10, 2017, 10:46:07 amEthics are an interesting thing. Some would argue that overcharging (beyond recouping development and manufacturing costs) for hardware and getting it made low wage country with little labour protection laws, is also unethical but I don't know whether this is the case or not here.A more relevant question is whether it's legal to use said software, with a third party hardware? Does the licence agreement contain a clause saying it is only to be used with official Saleae hardware? If not, they clearly don't mind you using it with third party hardware, so there's no ethical question to answer. If there is, then there it clearly is illegal to use the software with a clone.Saleae has issues a plea to the community at large to use the clones with software other than theirs. Regardless of the legal aspects, it would be a shame to see a company go under because of people who happily used their efforts without paying for any of it. They make good hard- and software and have been good sports about it until they felt they could no longer continue.It is all about being reasonable. I'm sure they don't mind a few people using their software, but if it starts weighing on the company, putting it at risk, it seems fair to point people towards very reasonable alternatives.If you insist on using the software, you might consider making a donation as compensation.Quote from: abraxa on August 10, 2017, 11:28:21 amBuy a clone, use it with Sigrok and everyone is happy. Let's not make this more complicated than it has to be.It would be horrible to pretend that not protecting your software or hardware is asking for it to be used by others. I think many people here would object vehemently to that notion.

author: cdev
author_rank: Super Contributor
timestamp: August 11, 2017, 12:04:38 am
content: Thanks to Sigrok (and Cypress's engineers' work) I now have an LA thats - as far as what I use it for, immensely valuable for me.There is definitely a lot more learning going on because of the cheap Fx2 devices making it easy to see whats happening "on the bus".And that helps bring a lot more people new electronics knowledge.If the original 8 channel Saleae Logic was cheaper I would have bought one, but it was just way too expensive for me at the time so I got a Sigrok-compatible LA and it gets used all the time, and I'm very happy with it.Edit: However, reading about it, their new LA seems really cool. So, now I am kind of interested in their newer offerings.Quote from: frenky onTodayat 05:36:01

author: cellularmitosis
author_rank: Unknown
timestamp: August 11, 2017, 12:56:12 am
content: I think the ethics argument would be a bit more palatable if Saleae offered an 8 channel analyzer which was more affordable. In the end, I ended up going with the $8 clone. If Saleae had an offering which was, say, $25, I might have considered it.However, their 8 channel model is currently $219. If the $8 clones didn't exist, I wouldn't have spent $219, I would have spent the weekend hacking something together myself.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 11, 2017, 01:45:19 am
content: You can also download the software for the Intronix.http://www.pctestinstruments.com/downloads.htmThe software runs without hardware present in a demo mode.You can play with things like labels and grouping stuff together, decoders, and especially triggering. Gets you a feeling for how they all basically work.Also take some time to learn about state vs timing mode and what it means.I also bought the cheap 24MHz analyzer but have not received it yet.

author: hamster_nz
author_rank: Super Contributor
timestamp: August 11, 2017, 10:07:14 am
content: This AmpHour episode is a good listen on the subject:https://theamphour.com/237-an-interview-with-joe-and-mark-garrison-subtly-spelling-sayleeay/

author: suicidaleggroll
author_rank: Super Contributor
timestamp: August 11, 2017, 02:43:32 pm
content: Quote from: abraxa on August 10, 2017, 11:28:21 amAre you actually arguingFORshitty DRM-protected software that almost universally restricts authorized users in an attempt to stop unauthorized ones? That's a terrible argument. Saleae left their software open so that it would be easy to use by authorized users, with the expectation that people would refrain from being dicks and abusing that privilege. It's against the license terms to use it with 3rd party hardware, it's immoral, it's unethical, don't be an asshole.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: August 11, 2017, 02:44:54 pm
content: Quote from: cellularmitosis on August 11, 2017, 12:56:12 amGo for it, nobody is stopping you, but talk to it using either your own software or open source software, not the proprietary Saleae tools. That's all anyone is saying.

author: Zero999
author_rank: Super Contributor
timestamp: August 11, 2017, 04:28:59 pm
content: Why don't they reduce the price of their hardware and offer to sell the software separately? You can buy their hardware and it includes one licence of their software, or you can just buy their software, to use on something you've made, or a third party product.

author: abraxa
author_rank: Frequent Contributor
timestamp: August 11, 2017, 07:30:41 pm
content: Quote from: suicidaleggroll on August 11, 2017, 02:43:32 pmI'm arguing about the fact that people call those FX2 breakout boards Saleae Logic clones. I understand that that's a catchy name and a lot of Chinese vendors sell them by adding "Saleae" to the item name. That is wrong, no doubt. I'm just trying to make it clear that they're really only breakout boards and that there is nothing morally wrong with purchasing them (and ignoring the CD that comes with them)

author: KL27x
author_rank: Super Contributor
timestamp: August 12, 2017, 09:50:51 am
content: QuoteI have to admit, if Sigrok and $8.00 hardware existed when I got my Logic, I am kinda doubtful I would have gone that route. But it looks like Seleae have upgraded to 10 bit ADC on every channel, since then. I think the 8.00 clones are just logic hi/lo like the original 8 channel Logic?

author: alm
author_rank: Super Contributor
timestamp: August 12, 2017, 10:07:21 am
content: Quote from: KL27x on August 12, 2017, 09:50:51 amYes, I am pretty sure all clones (at least the $8 ones) are of the original Logic which was basically an FX2 breakout board with some input protection and a nice case and leads. There may be clones of the original Logic 16 out there, but I have not seen any with analog channels. Whether this is worth the extra $ is obviously up to the buyer. I think the Saleae software is nicer than PulseView, especially the protocol decoding speed.Quote from: blueskull on August 12, 2017, 09:55:14 amUp to 16 kS sample memory is not amazing, especially with limited triggering. Can it do multi-stage triggering, e.g. look for this serial pattern? Can it do streaming sampling at lower sampling rates, like the Saleae ones, to get essentially infinite sampling depth?

author: hamster_nz
author_rank: Super Contributor
timestamp: August 12, 2017, 11:13:44 am
content: Quote from: blueskull on August 12, 2017, 09:55:14 amThere is also the Digital Discovery - up to 32 channels, up to 800MS/s (for 8 channels), 16 channel pattern generator, 2Gb of sample memory, virtual switches/LEDs for user interaction, a (low current) PSU, driven at the reference voltage,https://reference.digilentinc.com/reference/instrumentation/digital-discovery/reference-manualAt US$199, it is under the price point as the Saleae Logic-8, and has up to 4x as many channels (but zero analogue features).