Author Topic: saleae logic ??  (Read 6840 times)

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Offline SuperMiguel

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saleae logic ??
« on: November 22, 2010, 11:40:59 am »
What you guys think about the saleae logic is it any good?
 

alm

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Re: saleae logic ??
« Reply #1 on: November 22, 2010, 12:12:33 pm »
I have one and like it. It's a streaming USB (24MS/s, 8 channels, almost unlimited depth) type, as opposed to the FPGA (more channels, faster sampling rate, limited memory, examples are Zeroplus and Intronix Logicport) type. Since you're basically forced to use their software all the time, I think this is an important consideration. In my opinion, Saleae's software is really nice to use, and now the cross-platform version is released, it's regularly updated again. The fact that I can use it under Linux without any emulation was the deciding factor when I purchased it. The streaming USB analyzers don't tend to work well with virtualization, since they depend on max. USB throughput. Occasionally I'd like more channels or sampling rate, if I had the budget, I'd probably get the Intronix Logicport. But with modern serial protocols, 8 channels are often enough, and 8-bit MCU don't tend to communicate at more than 4MHz or so. The main exception is LCD displays, which often have parallel interfaces (HD44780 is just possible, graphical like KS006x is not). I haven't had any issues achieving the max. 24MS/s.

Last time I checked, the Zeroplus software was horrible, Logicport had many features, but felt a bit clumsy, and USBee was mediocre. USBee have rewritten their software (inspired on the Saleae software) since, but I haven't tried it. The bang/buck award goes to the open hardware OLS, but the software wasn't that mature last time I checked. It's hard to beat the $40 or so, however.
 

Offline TheDirty

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Re: saleae logic ??
« Reply #2 on: November 22, 2010, 12:45:12 pm »
I have one.  Software is nice.  It's worked for everything I've used it for, except one time when I needed to monitor an 8 bit data bus, plus some control signals, but that doesn't happen very often for me.
Mark Higgins
 

Offline SuperMiguel

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Re: saleae logic ??
« Reply #3 on: November 22, 2010, 01:11:46 pm »
how is that compared to something like this: http://tampa.craigslist.org/pnl/ele/2034386166.html
 

Offline Hypernova

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Re: saleae logic ??
« Reply #4 on: November 22, 2010, 03:44:41 pm »
Nice thing with unlimited memory at 24MHz is that you don't have to sacrifice timing resolution when you need to monitor ports across sever seconds.
 

alm

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Re: saleae logic ??
« Reply #5 on: November 22, 2010, 08:58:05 pm »
One important difference between modern logic analyzers and the older boat anchors is that the older stuff was designed as traditional logic analyzer, which means hook it up to the address bus of a CPU and follow the execution with inverse assembler. Not much use for this with modern MCUs with internal RAM/ROM and on-chip debugging. They're usually not that good at decoding serial buses, since these weren't that common when they were designed. The specs (channels / sampling rate / memory depth) are usually much better than anything affordable new. Make sure to get the pods, since these can be hard to get, and the analyzer is useless without them.
 

Offline thakidd

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Re: saleae logic ??
« Reply #6 on: November 23, 2010, 12:32:08 am »
Just got the OBLS in the mail from China. Hooked it up to a few things and noticed that it is spot on with the JAVA software but also noticed that it could only grab a part of the serial data I was sending off of a simple Arduino. My setup was this...Programmed the Arduino to transmit over simple serial (pins 0 and 1) "Jason's new Open Bench Logic Sniffer". Got decent results but noticed that it could not quite interrupt the whole message with the built in analyzer. Seemed to go by too quickly the higher (towards 100 MHz) and seemed to not read correctly the lower I went. 100Khz seemed to work just great but after analysis only decoder the first 10-11 letters sent from the Arduino.

Questioning whether I should get the Saleae at this point. Could give better results on serial/spi/etc but the OBLS might be the way to go for faster protocols. Either way, it was $40. I am not bitching (too much)!

The question is...How might the OBLS be modified to have more depth?
 

Offline SuperMiguel

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Re: saleae logic ??
« Reply #7 on: November 23, 2010, 03:16:02 am »

All i want to do is connect something to my atmega chip, or my arduino, and know if the pin is 0 or 1.. I been using my oscilloscope but it only has 2 channels and some times i need to know more than 2 pins at the time.

So hopefully this will do the trick.

wondering if i should get the http://www.seeedstudio.com/depot/preorder-open-workbench-logic-sniffer-p-612.html?cPath=75 for a 1/3 o the price
« Last Edit: November 23, 2010, 03:26:27 am by SuperMiguel »
 

Offline FreeThinker

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Re: saleae logic ??
« Reply #8 on: November 23, 2010, 03:50:35 am »
Machines were mice and Men were lions once upon a time, but now that it's the opposite it's twice upon a time.
MOONDOG
 

Offline Hypernova

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Re: saleae logic ??
« Reply #9 on: November 23, 2010, 12:49:04 pm »
Just got the OBLS in the mail from China. Hooked it up to a few things and noticed that it is spot on with the JAVA software but also noticed that it could only grab a part of the serial data I was sending off of a simple Arduino. My setup was this...Programmed the Arduino to transmit over simple serial (pins 0 and 1) "Jason's new Open Bench Logic Sniffer". Got decent results but noticed that it could not quite interrupt the whole message with the built in analyzer. Seemed to go by too quickly the higher (towards 100 MHz) and seemed to not read correctly the lower I went. 100Khz seemed to work just great but after analysis only decoder the first 10-11 letters sent from the Arduino.

Questioning whether I should get the Saleae at this point. Could give better results on serial/spi/etc but the OBLS might be the way to go for faster protocols. Either way, it was $40. I am not bitching (too much)!

The question is...How might the OBLS be modified to have more depth?

If you really have to read them at reasonable resolutions over sever seconds then yes the saleae or others like it are pretty much mandatory. In fact it can sample at 24MHz for 10GS, that's nearly 7 minutes of data. The 24MHz will be more than sufficient for I2C and 921600 serial. You are probably pushing it for 10MHz SPI but other wise it would perform beautifully.
 

alm

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Re: saleae logic ??
« Reply #10 on: November 24, 2010, 06:39:39 am »
The question is...How might the OBLS be modified to have more depth?
FPGA with more RAM or external RAM. A second revision with external RAM was planned, but I don't know if it will materialize. There's a reason why many FPGA-based logic analyzers have these kind of limits.
 

Offline tinhead

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Re: saleae logic ??
« Reply #11 on: November 24, 2010, 09:35:08 am »
OBLS is based on Sump LA (or in principle sump LA with PIC for communication).
I have two private versions of sump LA design based Logic Analyzers, both based on Altera Stratix :
- EP1S10 - with huge memory per channel and 64 chans
- EP1S80 - with fast clock/sample rate but only 64k per channel - which is even more than Intronix LogicPort.
So you can see there is enough room in sump LA design for improvements, it is only question about price
(the Spartan 3E used in OBLS is 440x cheaper than Stratix EP1S80)

There is another one free LA design available, miniLA:

http://minila.sourceforge.net/

I did some tweaks in VHDL and my buddy MockUp did some circuit improvements,
now we have 32 chans with 512k sample memory per channel, 100MHz sample clock, USB isolator (ADUM4160)
and of course USB powered (with some brand new DC/DC converters from Murrata).

http://www.mikrocontroller.net/articles/Minila_Version_MockUp

Of course it costs more than OBLS (actually we have ~5 left, price about 160USD), but as always - you get what you paid for.

And btw, i have Saleae too, i do support people like Joe. For protocol sniffinig (like unknown displays), reverse engineering it is just perfect,
you can't have too much sample memory .. never.
« Last Edit: November 24, 2010, 10:08:45 am by tinhead »
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 


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