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Topic: anyone knows a decent affordable logical analyzer ? (Read 4433 times) previous topic - next topic

fourchette

following my post about the  08SUR-32S connectors, my ultimate goal is to monitor data exchanges

i beleive the info is likely to be usb data, i know it's pretty much master/slave approach

i think i'm likely to need what's often refered to as a "logic analyzer" (not sure though)

once i'd get the analog measures, i'll need to convert that into something usable

to acquire the data i was thinking of using maybe lxardoscope
http://hackaday.com/2011/09/20/lxardoscope-is-a-linuxarduino-oscilloscope/
but what will perform the sinusoide conversion into hexadecimal numeric data then ?

i've also though of the usbee combinaison

http://www.usbee.com/products.htm
it looks like the cheapest option would be
USBee SX (hardware) ==> 169 USD
USBee Suite Pro (software, works on windows) ==> 299 USD

wow... even though both hardware/software may be good, honestly spending 500 USD sounds a bit extreme given the context. not to mention that i'm not  even sure i'll be capable of using it anyway :(

i've also heard of the bus pirate thing http://dangerousprototypes.com/bus-pirate-manual/
=> its 30 USD price tag sounds much more reasonable for educational purposes but still i'll have the analog data -> numeric data conversion to be performed somehow and i dont know how...?


anyone would help me point in the right direction ? i'm feeling kinda lost here :-|

thanks

cyclegadget


  Here is a recent thread, http://arduino.cc/forum/index.php/topic,74216.0.html
Good links: Eagle tutorial= http://www.youtube.com/playlist?list=PLDE1858BD83D19C70
General Arduion tutorials = http://tronixstuff.wordpress.com
http://www.gammon.com.au/forum/bbshowpost.php?bbtopic_id=123

Graynomad

#2
Oct 08, 2011, 02:08 am Last Edit: Oct 08, 2011, 02:22 am by Graynomad Reason: 1
AFAIK Dangerous Prototypes/Gadget Factory haven't got a multi signal device, all their analysers are digital only.

They have been working on this

http://dangerousprototypes.com/docs/Dangerous_DSO

But I don't know if it's available yet.

______
Rob


Rob Gray aka the GRAYnomad www.robgray.com

FeersumEndjinn

http://www.sparkfun.com/products/8938

$150 including cross-platform software - the build quality is exceptional, and I highly recommend it.

Graynomad

That's the Saleae Logic, I've got one and they are great, no analog though.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

Grumpy_Mike

Quote
wow... even though both hardware/software may be good, honestly spending 500 USD sounds a bit extreme given the context. not to mention that i'm not  even sure i'll be capable of using it anyway

That is nothing for a quality instrument, it won't even get you a decent scope. I spent £10,000 on a logic analiser (at work) when I lived in a house that cost me £8,000.

FeersumEndjinn

Quote
That's the Saleae Logic, I've got one and they are great, no analog though.

______
Rob


Correct, but the original question was for a logic analyzer to monitor USB data exchanges so the Saleae logic would be his cheapest option.

fourchette

Quote
Quote
wow... spending 500 USD sounds a bit extreme given the context.

That is nothing for a quality instrument, it won't even get you a decent scope. I spent £10,000 on a logic analiser (at work) when I lived in a house that cost me £8,000.


at work -- it used to be a factory assembling & repairing electronic devices -- they have a complete room full of dozens of unused supposedly expensive HP oscilloscopes somewhere in the back of a warehouse. They have not been used for years. kinda forgotten there. I asked if i could be donated one to have fun at home but i have been told that even though they are not used now, they are too expensive to be donated to employees. i have not been given a price, but it seems they were paid about several thousands EUR

i have used oscilloscopes back at school, it was kind of fun, but well... playing video games was fun too back then :)
so i have not used any since high-school and embedded hardware is a recent hobby of mine. basically i am not sure i could do anything with an oscilloscope, and an expensive one feels like it might not be a good option of a n00b like me. not to mention that i doubt the oscilloscope would convert the UP/DOWN signals into usable bytes like wireshark does with network.

i have the feeling they will be sent to the trash in the next few months
Should i take one in the trash for a future use then ?

fourchette

Quote
Quote
That's the Saleae Logic, I've got one and they are great, no analog though.

Correct, but the original question was for a logic analyzer to monitor USB data exchanges so the Saleae logic would be his cheapest option.


as long as it gets the job done quickly without days of scratching my head not understanding what is going on
==> i guess that's enough.

once i'm used to logic analysis then i will know what i need / want / dont want ==> then i may target something more professional.

for now "cheap that works" is exactly what i am looking for.

so will Saleae be able to understand/capture/decode raw usb frames ? (it is digital signal indeed, sorry if i wasn't clear on that)

Important: i have never read the hundreds pages long of official low level USB norm/protocol definition (what i will call here the "transport protocol"). However i am expert with the targeted peripheral "application-level protocol" i want to see on the device under test while it is operating.


cyclegadget

Should i take one in the trash for a future use then ?

Grab them all if possible, the worst thing that could happen is that you would trash them yourself. Maybe, you could sell them for an easy profit.
Good links: Eagle tutorial= http://www.youtube.com/playlist?list=PLDE1858BD83D19C70
General Arduion tutorials = http://tronixstuff.wordpress.com
http://www.gammon.com.au/forum/bbshowpost.php?bbtopic_id=123

madworm

You can answer that question yourself.

a) whats the sample rate of the logic analyzer?
b) whats the raw bit-speed of the usb link?

a) should be at least 10x of b)
• Upload doesn't work? Do a loop-back test.
• There's absolutely NO excuse for not having an ISP!
• Your AVR needs a brain surgery? Use the online FUSE calculator.
My projects: RGB LED matrix, RGB LED ring, various ATtiny gadgets...
• Microsoft is not the answer. It is the question, and the answer is NO!

Graynomad

Quote
so will Saleae be able to understand/capture/decode raw usb frames ?

No, it doesn't have a USB decoder.

Also, if you are talking about sniffing the raw USB signals they aren't 5v logic, that's why I was talking about the Salaea not having analog.

The cheapest analyser I know of that can do this is the Usbee AX that you already know about.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

fourchette

ok. i'll try to grab my hands on such oscillospes then (rumour is : "everyone wants one", so you guys are probably right anyway ;))

here is some info i found in the documentation regarding the usb device

Quote
USB Low Layer Protocol
The integrated USB driver of the xxxxxxxxxxx device emulates a RS232 serial port.
The xxxxxxxxxxx device is processed as a Communication Device Class (CDC), in accordance with the "USB Device Class Specifications, version 2.0" available from the http://www.usb.org/ web site, in "developers, document" section.
The xxxxxxxxxxx device use the full speed transfer rate 12 Mbits/s, and is compatible with USB 1.1 and USB 2.0 Host Systems or hubs.


thanks madworm for the rule of thumb, it makes the picture much clearer now.

so if the transfer is 12Mbits/s i need about 120 "capture per second"
assuming this is the Msps unit mentioned there
www.usbee.com/products.htm

then i need the USBee RX as it's the only one offering 100 Msps sampling rate. that's a 1945 USD

however, it seems the Beagle 12 made by totalphase http://www.totalphase.com/products/beagle_usb12/ would do the job for 475 USD

i have also seen the
Quote
You can get a Saleae Logic clone for $50, I'm talking about the Mini Logic on iTead Studio

on the other post
is it this ? ==> http://iteadstudio.com/produce/seleae-logic-usbee-ax-usb-blaster/
sorry if i sound stupid, but this is some sort of a "3 in 1" cheap chinese copy, right ? (no offense to chinese ppl)
and it seems the highest sample rate is 24 msps which not enough, so buying this would just be a waste of money


so the Beagle 12 is the best option here then, right ? anyone ever tried it ?

NiHaoMike

It's surprising just how just how easy it is to make a logic analyzer. All you need is a FPGA board.

Making a scope is much harder, since you'll need to make a good analog front end. I recently finished a design for a digital power meter AFE and it was surprisingly hard to design even though it only has a 5kHz bandwidth. (The main problems were accuracy and crosstalk.)
"Optiboot: the Tiffany Yep of Arduino bootloaders."

fourchette

Open Vizla on paper seems to be exactly what i need
==> http://www.kickstarter.com/projects/bushing/openvizsla-open-source-usb-protocol-analyzer

unfortunately it is not finished just yet :'(

given that bushing from hackmii team is behind, i'd bet it should end up with interesting results

btw it looks like it certainly wasn't a simple weekend project


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