Go Down

Topic: Hobbyist Logic Analyzer (Read 2 times) previous topic - next topic

sdebruin

Hello Arudino Community,

Although I am an avid Arduino user, this is my first post to this forum.

I am a researcher at the University of Michigan and I am working on a project to bring lab equipment to the hobbyist user. We are not trying to compete with Saleae, merely create an affordable (~$25) logic analyzer for hobbyist users. For reference, the Saleae units are ~$150 and are typically out of range for a hobbyist user looking to spend $30 on a project. We are using an FPGA coupled with the TI CC2540 Bluetooth chip to create a front end for a smartphone logic analyzer. The GUI will be on the phone, as well as most of the data storage.

We are in the process of designing our hdl for the FPGA and I was wondering if the Arduino community had any inputs on this project. After all, this is for you. My lab already has several products on Sparkfun and if this project goes through, it will hopefully be available on Sparkfun as well. With that in mind, what do you, the user, want in a low-end logic analyzer?
1. Is 8Msps fast enough?
2. Is 250M samples in storage enough?
3. What will be typical applications that you will use this for?
4. Is four inputs (enough for typical SPI) enough or do we need 8 like Saleae?

Thank you very much for your help. I hope to use this project as an opportunity to give back to the hobbyist community that fostered my love of embedded electronics. Go Blue! 

Sam

frank26080115

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

Open Bench Logic Sniffer can do 70 MHz with 32 channels, you should aim for at least 24 MHz with 16 channels, which should be doable for your target price and hardware.

The 8 channels on my Saleae is barely enough for a lot of what I've used it for, you should try for more channels.

I think 250 million samples should be enough if you use compression.
Freelance engineer, consultant, contractor. Graduated from UW in 2013.

Graynomad

8Msps is borderline, if you're using an FPGA why is it restricted to this?

250M samples is plenty (how on earth are you getting that much?), the open logic sniffer only has a few k (not enough IMO although it is still a very useful gadget).

More channels is always good but I find 8 is enough for just about everything I do.

One of the most important features of an LA is triggering, what are you doing in that respect.

Just re reading your post I assume the huge storage and lowish speed are due to the data being streamed to the phone.

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

dhunt

Have you seen the two Dangerous Prototypes analyzers?  The Logic Shrimp is 4 channel, 20MHz, 256K samples and the Logic Sniffer is 32 channels at 50MHz 6K samples or 16 channels at 100Mhz with 12K samples.

They use an open source analyzer project Sump Analyzer Client that you might be able to target with your project giving you a ready to run client.


TonyD


Have you seen the two Dangerous Prototypes analyzers?  The Logic Shrimp is 4 channel, 20MHz, 256K samples and the Logic Sniffer is 32 channels at 50MHz 6K samples or 16 channels at 100Mhz with 12K samples.

They use an open source analyzer project Sump Analyzer Client that you might be able to target with your project giving you a ready to run client.

Yeap, the Dangerous Prototypes analysers should suit your application and they are well support at their website

pito

#5
Oct 06, 2011, 09:54 pm Last Edit: Oct 06, 2011, 10:01 pm by pito Reason: 1
..Logic Sniffer does 200MHz sampling freq with 16channels.. You can hardly design something better with Spartan3 than the LS does.. What is still open are the probes' design for LS - there are none for such frequencies, those probes they deliver are crap.. P.

Go Up