Low cost Logic Analyser

Hi,

I would like to buy a low cost Logic Analyser. I´ve found these devices:

Any recomendation?? Any experiencie with them?

Thank you! ;)

Regards,

Igor R.

I use the Saleae and think it's fantastic, no experience with the others.

EDIT: Just checked out the others, the LAP-C is the standout in term of features, then the Bus pirate, then the others are about the same. If you need the high speed then maybe the LAP-C (but I don't know what the price is and they make it hard to find out), otherwise they will all do pretty well.

What will you be using it for?

BTW: We have exactly the same number of posts. :)


Rob

I have used a Bus Pirate -- http://www.seeedstudio.com/depot/bus-pirate-v3-assembled-p-609.html?cPath=61_68

It has a very rudimentary 4-channel logic analyzer capability. It's fussy to use, but extremely cheap and is capable of useful work.

I have a USBee SX and I like it a lot; it's a solid performer and not too expensive.

I have used a Saleae for a couple of hours, and I plan to buy one when I have some more tool budget. The software is the real standout for this one -- incredibly intuitive and easy to use.

The LAP-C is a huge win in terms of features; how does the price compare?

Thank you for your replies.

The prices are:

  • Saleae is 149 euros.
  • LAP-C 16032 is $120.00 (plus an special introductory offer: 2 free additional protocols).
  • USBee SX is $169.
  • Open Logic Sniffer is only 49 euros.

Now Saleae offers a SDK to develop your own app in .NET... From FAQ: " Is there an SDK available? Yes, right now we have a low-level data access SDK. It's still in development but email us and we can send you the latest. We're also working in an SDK for making your own protocol analyzers, but this isn't ready quite yet. " One good feature, it´s you can have a large capture, although limited to 24 MHz.

LAP C 16032 looks very good.... maybe it´s the best option price vs features. Although, if you want to have more addtional protocols, you have to pay for it. But right now, with the offer you can get the same than the other hardwares..... I´m not sure if 512 KB of capture memory will be a problem....

USBee SX right now allows create your own protocols. "The USBee SX Test Pod is a HUGE sample buffer PC and USB based multifunction logic analyzer and digital signal generator in a single compact and easy to use device and includes a powerful bus decoder that shows ASYNC, I2C, SPI, 1-Wire, USB, CAN, I2S, SMBus, Sync Serial, PS/2 and even your own Custom Serial Bus data.."

I´m interested to have CAN bus... Have you tried with Saleae or USBee ?

Graynomad now you have to reply to have again the same posts´ number.... ;)

Graynomad now you have to reply to have again the same posts´ number....

OK.

I win :)

I have to say that looking at the specs and prices the LAP-C looks pretty darn good and it has a CAN decoder. But if you don't need the speed then there's little benefit.

As for the 512k buffer, do the maths re sample rates for your typical app (CAN @ 1MHz?). At 10x1MHz sample that's only .5 seconds of sample which isn't great. OTOH if it is clever and only samples deltas then it might be OK.

With the Saleae you can sample for a forthnight then drill down to the important bit, same with the USBee it looks like and that also has a CAN decoder.


Rob

I´ve found a similar topic in other forum: http://www.rcgroups.com/forums/showthread.php?t=1023934

Zeroplus is better because you have more speed, but size limited.Not an user friendly soft.Limited the CAN bus protocol analyser (for CAN bus based protocols).
USBee looks a very good and allows to add your own protocols.
Saleae has probably the best software interface.

???

Why is that there’s never a clear winner?

Wait a minute, I just saw this on the Saleae site

Currently supported are I2C, Async Serial, SPI, 1-Wire, CAN, I2S, PCM, and UNI/O, with more on the way

I’ll have to download the latest version, but if it supports CAN then I’d say definately get the Saleae.


Rob

UPDATE: I just downloaded the latest version and CAN is supported. The interface looks better as well, it seems to be easier to select a protocol analyser.

I'd recommend downloading the software and having a play in simulation mode.


Rob

Thank you Rob for your comments. :smiley:

Rocketgeek, what about your experiences with the USBee SX? I like that you can create your own protocols and it can work as generator.

The Open Logic Sniffer is the best hardware (100 MHz) for the minimum price ($49.95). It uses SUMP logic analyzer client. It´s open source and at the moment it has not the level of the other soft interfaces and doesn´t supports many protocols (as a protocol analyzer).
This client looks good => http://www.lxtreme.nl/ols/
Original client => http://www.sump.org/projects/analyzer/client/

Any experience with it?? I can´t find reviews about it.

Too many options…hehehe :wink:

I haven't used the SDK for USBee, because I haven't had need of it, and I've only used the generator to familiarize myself and once to un-bork an AVR from a mis-set fuse. I like the simplicity and robustness. I haven't figured out a way to run some channels as outputs and others as inputs, but that's likely for lack of trying. :)

I have to say that looking at the specs and prices the LAP-C looks pretty darn good and it has a CAN decoder. But if you don't need the speed then there's little benefit.

As for the 512k buffer, do the maths re sample rates for your typical app (CAN @ 1MHz?). At 10x1MHz sample that's only .5 seconds of sample which isn't great. OTOH if it is clever and only samples deltas then it might be OK.

With the Saleae you can sample for a forthnight then drill down to the important bit, same with the USBee it looks like and that also has a CAN decoder.

Note: I've only looked at the Saleae, USBee and Zeroplus so I can't comment on the others. I have a USBee SX and have extensively played with the demo software for the other 2.

As far as "sampling for a forthnight" it depends on your environment. Also, better triggering capability, can often eliminate the need for having to sample so much data.

A big difference is that the ZeroPlus design has full buffer memory inside the device. The Saleae and the USBee do not. What that means is that the Saleae and the USBee need a very fast USB bus with no other devices sharing it (to avoid any lantency) in order to function because their internal memory is very limited.

The LogicCube "takes a picture" of the lines and stores all the samples inside the memory first and then dumps that full trace across the USB. The other two stream the data to the host in real time using only a very small buffer inside the device.

Also, the best I can tell, is that the LogicCube has trigger logic inside the device and the other two (at least the USBee) stream all the data to the host and then handle the triggering in the host by looking at the incoming data in real-time. It works but requires a very fast low latency USB.

The logicCube also has some methods of compressing the data samples so that you don't need to store the full data on each sample. This can extend the buffer to act as a larger buffer.

I have a USBee SX and it is nice but when using Vista (dual core 2.8ghz Athlon on an HP slimline) it had problems keeping the USB bus streaming so traces would fail at the higher sample rates > ~12mhz. (worked fine with XP on my Acer Netbook at full 24Mhz sample rate)

The Saleae is a similar design to the Saleae but also has support for MAC and Linux so you are not stuck having to use Windows.

Since the Zero Plus has its full trace memory internal to the device the USB speed and its latencies are removed. This means that you could run the ZeroPlus and its software in environments like a VM or on slower processors or loaded USB busses than would not be possible with the Saleae or USBee. The ZeroPlus design will allow it to always operate at its maximum sample rate of 100mz where as the other designs will require you to lower your sample rate to deal with USB latencies and in some cases it may not work at all, like under a VM.

Remember that with USB even devices that are "idle" consume USB bandwidth (thank you Intel) and if they are slow speed devices like perhaps a keyboard or mouse, your bandwidth is dramatically affected if those slow devices are sharing the same USB internally. A single slow device on a USB will halve the USB bandwidth available to a highspeed device if they are on the same USB even if the slow speed device is "doing nothing" - that is a limitation of the USB protocol.

With respect to pricing of the ZeroPlus, pay close attention to what comes "in the box". Often the low end 032 model does not come with all the clips. That can add $20-30. Yet the 064 model often does come with the clips so it isn't as much more as it might look at first to jump from the 032 to the 064 model.

The USBee can act as a signal generator as well as analyzer. You can define waves or even play back sequences on multiple pins. This can be a very useful feature to simulate hardware.

USBee has more signals than the Saleae. The USBee can be clocked with an external clock and has a separate trigger so you can sample 8 full data lines using an external trigger. You cannot do this on the Saleae. (Obviously you can also do this on the Zeroplus as it has 16 lines)

To me it comes down to a few features that will make the decision. If you need more than 8 signals - ZeroPlus wins. If you need native MAC or Linux support Saleae wins. If you want signal generator support USBee wins. If you need higher than 24mhz sampling rate or want to avoid USB latency issues ZeroPlus wins. (Remember that you need the sample rate to be at least double your signal rate so 24mhz means you are limited to about 12 mhz signals) If you need an external trigger with more than 7 data lines, avoid Saleae. If you want/need HUGEly long traces, avoid the LogicCube. (But keep in mind that if you slow the LogicCube down to 24Mz the trace will be quite large)

They all have their pluses and minuses.

At the time I made my decision (about a year ago) the USBee s/w was better and I opted for it. However, in my case I often find myself needing more than 8 signal lines and higher sample rates and so the LogicCube would have been a better choice for me. (I often use my analyzer to time software or look at hardware strobes and a 24Mhz sampling rate isn't good enough as you can only reliably measure down to about 80ns with it)

--- bill

Thank you Bill and rocketgeek for your replies!!!

I´m going to wait one day more before to make a decision.... ;)

cheers!