EEVblog #436 - Saleae USB Logic Analyser Review & Teardown

[EEVblog]

Review and teardown of the 8 channel Saleae USB Logic Analyser
http://www.amazon.com/gp/product/B004G4ZKA6/ref=as_li_ss_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B004G4ZKA6&linkCode=as2&tag=eevblogstore-20



Dave.

[David_AVD]

"Private Video"   

[somlioy]

Seems like its the wrong video attached.
Correct:

[arekm]

http://mdiy.pl/uniwersalna-plytka-analizatora-logicznego/

DIY version of that with VID/PID changed by just pressing micro switch (Attiny25 for that), so it can present itself as different logic analysers. Unfortunately no idea if free software exists for it and without it it's useless :-(

[amyk]

http://mdiy.pl/uniwersalna-plytka-analizatora-logicznego/

DIY version of that with VID/PID changed by just pressing micro switch (Attiny25 for that), so it can present itself as different logic analysers. Unfortunately no idea if free software exists for it and without it it's useless :-(

http://sigrok.org/wiki/Fx2lafw

Note that some of the clones have a buffered input too, as well as 16-channel +analog capability.

[PChi]

Thanks for the Review and Teardown. I have used the 16 channel one at work and agree with your assessment that the trigger facilities are the major limitation. Though having said that the capture length (compared to Oscilloscopes) and the ease of use are good and it has proved useful on SPI and I2C.

[alm]

I agree with the verdict on the basic software. The interface is intuitive, but no major features have been added since it was rewritten in 2010. For example, I complained about the limited triggering options when version 1.1 was released in 2010, but I think the only features that have been added have been Logic16 support, an SDK for analyzers and some extra analyzers.

[dannytt]

you can find a china copycat for only rmb 40
http://item.taobao.com/item.htm?spm=a230r.1.10.25.8qX8Qp&id=18225744876

[baoshi]

AFAIK Saleae logic and USBee are based on the same CY68013A chip. I have a clone that can present itself to be either Saleae or USBee. After comparing the software I found Saleae is far better than USBee in terms of USB throughput.

There's another useful 3rd party free software called "PWM Logic" that turns Saleae logic into a PWM generator.
http://www.brrrbaybay.com/index.php/pwm-logic/about

Bob

[hammil]

In fact, all you need is the dev board. The layout is damn near identical to the one in the product...

http://www.ebay.co.uk/itm/3-3V-5V-CY7C68013A-56-EZ-USB-FX2LP-USB-2-0-Develope-Board-Module-Logic-Analyzer-/281036187315

You don't even need any firmware - all you need to do is change the Product and Vendor IDs using this utility (google it) - all the firmware is transferred from the PC software.

I bought one, and I can confirm that it works fine.

[tinhead]

wondering only why you got these unnamed clips, that should be the E-Z Hooks. Money savings?

I bought my first Saleae right after they started doing the business, year ago however the PCB stopped to work.
For sure i could repair it, but i thought "let's see first what they will do with [long time expired warranty] customers".
And here is the difference between one hung low clones and org. Saleae - they simply send me replacement unit, on no costs.

Sure, i've paid somehow the support by paying the 150$, but i got even more than expected, and that's really unique today.

[alm]

wondering only why you got these unnamed clips, that should be the E-Z Hooks. Money savings?

Yes. They used to advertise that they were shipping genuine E-Z hooks, but they stopped doing that a while ago and started shipping cheaper clips.

[hammil]

And here is the difference between one hung low clones and org. Saleae - they simply send me replacement unit, on no costs.

Sure, i've paid somehow the support by paying the 150$, but i got even more than expected, and that's really unique today.

I guess, but... There's an order of magnitude difference between $12 and $150.

If I bought an original, it would be for the nice enclosure. Really rugged and portable. But if it'll just sit on my computer desk, I'd pay the $12, and if it broke, buy another one for $24 total.

[AlfBaz]

I've heard nothing but good things about this 34 channel one. At $400 you certainly are getting better value when you consider the price of the 16 channel saleae one
http://www.pctestinstruments.com/index.htm

[tinhead]

it seems that Saleae is working on better I2C decoder - with search functionality

http://community.saleae.com/node/332

And it seems the current Beta version is already supporting different proticols, e.g. JTAG

Well, the biggest news is we have several new analyzers! We now have JTAG, PS/2 Keyboard & Mouse,
Atmel Single Wire Interface, and LIN! (Local Interconnect Network)



And this is why it's worth to pay money, not only because of (really nice) enclosure and very good support.
A $12 china clone alone is not doing any work, not even if you pay extra 100$ bucks to chinese seller - they will simply
not write own - working and english (not even ask about multilang) version - software (oh well, if they find a ready-to-use
source somewhere then yes, then you will get sw with new icons and company logo ... ).

[hammil]

Ah... The thing with getting the board I mentioned, is that you can use Saleae's own software with it. I guarantee it works.. I had some problems getting a later version to work with it, but I think that was just a glitch with their software at the time.

EDIT: This, I would imagine, is what the chinese clones do as well.

[exp1]

Ah... The thing with getting the board I mentioned, is that you can use Saleae's own software with it. I guarantee it works.. I had some problems getting a later version to work with it, but I think that was just a glitch with their software at the time.

EDIT: This, I would imagine, is what the chinese clones do as well.

At some point Saleae implemented some routines in their software to identify chinese clones to stop people from using their software without paying.

EDIT: Or rather, what triggered the decision IIRC were chinese ebay sellers bundling the Saleae software with those cheap evaluation boards.

[free_electron]

all these thingies like USBee, Salae et al are based on the well known cypress chip. they essentially flick the FIFO's of that device in permanent streaming mode and go off captureing what comes in. There is no real software involved apart from configuring the endpoints and turning on the stream feature.
The 8051 inside only configures the strema port and then lets the hardware rip.

The smarts sit in the pc side software.

State analysis is not possible as there is no clock input. the problem is that a USb device is a slave only and this would require local buffer until the host can poll for the next packet.

The protection diodes used are special. they actually are esd ptoection structures for very high bandwidth applications like DVI busses. DVIULC6-4SC6 is the part number. it is essentially a transil combined with 8 diodes allowing to protect 4 pins. the capacitance is in the order of half a picofarad.

the on board eeprom only holds a vid/pid pair tat allows the pc side software to ind the device and upload the firmware for the 8051. you can actually store firmware in that eeprom as well but these devices don;t use that feature. they just upload it at first contact. the cypress chip has no real rom and uses ram only. at powerup it either fetches its firmware from the eeprom or waits for the Pc to feed it through the usb port.

the one-hung-lo clones use a different eeprom with a mechanism to switch the addresses around . that is what they can detect.

i have been to their open-house days a couple of times ( they are close to candlestick point in san francisco ) and they had a whole bag of fake clones.
They use altium to make their boards and schematics.
the 16 bit version has a cpld on board to multiplex the 16 bit inot an 8 bit stream for the cypress chip.

keep in mind that this is essentially a streamer. it just samples the state of the 8 input pins as fast as it can. all post processing is done on the pc. as it is capturing it cannot process the data. so setting advanced triggers like 'missing acknowledge' etc are not really possible at it woudl depend on the speed of the pc to be able to crunch it... on a slow pc it would miss packets... so it is all necessarily done in post processing. this is the difference with real logic analyser that have hardware engines to do sequentieal states and fire off the trigger. the logic analyser essentially has a custom 'cpu' that can do a number of custom compares and if the sequence matches they fire off.

these thingies are useful for some fast work , but they are no match for the hardware decoders buitl into MSO scopes. then again you have to tack on a digit to the cost ...

[cloudscapes]

This video has made me really want an MSO/LA with realtime decode. Unfortunately, it also looks like I'd have to spend more than a couple grand for that. 

I have the Saleae. It's helped me in a few occasions but mostly it stays in the bag. That it's not realtime is a major disadvantage for the time of signals I usually deal with.

[alm]

keep in mind that this is essentially a streamer. it just samples the state of the 8 input pins as fast as it can. all post processing is done on the pc. as it is capturing it cannot process the data. so setting advanced triggers like 'missing acknowledge' etc are not really possible at it woudl depend on the speed of the pc to be able to crunch it... on a slow pc it would miss packets... so it is all necessarily done in post processing. this is the difference with real logic analyser that have hardware engines to do sequentieal states and fire off the trigger. the logic analyser essentially has a custom 'cpu' that can do a number of custom compares and if the sequence matches they fire off.

If it can do billions of samples of pre-trigger data, then some buffering for trigger decoding shouldn't be a big deal. 24 MB/s isn't exactly a fast data rate for a modern CPU, and real-time is not required if it can buffer for multiple seconds. It's not like the current triggering is hardware-based, the edge/level triggering is also software-based. Some protocol decoders might be too complex, but basic state machines like in the old HP logic analyzers should definitely be possible.

[cyr]

Fancy box, fancy zooming animation, but lacking basic trigger functions? 

Being able to trigger on a specific event is essential to a tool like this, and with all the processing done on a multi-ghz, multi-core CPU there really is no excuse...

[jpatten]

I own both the Logic and Logic16 and really like both of them. While it's true the software lacks some features found on much more expensive analyzers, in my work the ease of use of the software more than makes up for this. In my experience the lack of advanced triggering options isn't a huge issue when you can record data for very long periods of time. The ease of navigating with the mouse makes it simple to browse through and see specific events, though I agree search would be a nice feature to add.

One thing I've found really handy is the ability to export data in a variety of formats. So for example if you have an rs485 network with a bunch of custom devices on it speaking a custom protocol and you want to make sure they are all communicating correctly you can feed the data from Logic into a Python script or something that verifies everything. The script can print out timestamps where the protocol is violated for further investigation inside the Logic software. For this sort of debugging of networks of embedded sensors and such I've found the Logic to be much easier to use than the analyzer on my scope.

[Bored@Work]

I own both the Logic and Logic16 and really like both of them.

You just signed up, your first posting is about telling us how good the LAs are. So, what is your relation with Saleae?

[shashwatratan]

Hello every one and Hi Dave! love your blog and show. It is my first logged in time on eevblog forum. I am not very good with written words So it always kept me on guest side.     

  I have logic aver 2 years now. It is quite a handy device for basic bus analysis. My favorite thing about Saleae logic is that "It is Very Basic". It is not meant to do too much I mean it is obviously not the replacement of a real thing.
  yes it is little expensive for being just "Basic" but they have good customer support, simple and clean GUI and most importantly it is very Compaq. So i don't mind keeping it in one corner of my work space. It helps when i don't want to fiddle and do all the menu and settings on larger signal analyzer or scope for some simple thing. I agree with Dave and cyr, it should be able to trigger on a specific event.

[jpatten]

I don't have any relationship with them other than as a satisfied customer. I signed up just to make this post as I think Saleae has a great product and Dave's review wasn't super positive about it. (Nothing against Dave, generally I really agree with his reviews...)

I can understand how you might think I'm a shill or a robot so here's a bit about me: I run a small design/technology company in NYC called Patten Studio. We use Logic to debug communications protocols in projects like this LCD ribbon sculpture http://www.pattenstudio.com/projects/ribbon and this science museum exhibit http://www.pattenstudio.com/projects/chem.