Logic analyzers

Phil Hobbs · 2023-01-10T22:12:36+00:00

We've been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese knockoff of a Saleae Logic 8. It's been pretty handy for characterizing the ADC in a bathymetric lidar chip we've been helping design.It'll stream data forever at 16 MS/s. However, at higher sample rates it quits after ~100k samples. Sheesh, and we spent eight bucks on it. ;)The USB form factor is nice, because it's the sort of instrument you want to pull out and attach down in the guts of some gizmo, and with USB you can just use a longer cable, which is convenient.Sooo, I'm considering buying something a bit better than our $8 Chinesium knockoff. Suggestions?ThanksPhil Hobbs

Jan 10, 2023 Last reply: 3 years ago 35 Replies

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Michael Schwingen 3 years ago

If you can use it with sigrok, it should be quite future-proof. USB works fine if you don't push it to the maximum possible throughput - a USB3 connection has advantages.

What I like about the USB logic analyzers is that you can record huge amounts of data (limited by PC memory, and the software does on-the-fly compression) and later zoom in on the details - with a classic analyzer with integrated memory, you need to setup triggers beforehand - buf after triggering, those can be faster.

What is better depends on the problem you are analyzing.

cu Michael

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Phil Hobbs 3 years ago

With our stuff, there are usually three or four boat anchors in use already, so having the logic analyzer be unobtrusive is a win.

Cheers

Phil "Still trying to figure out that weird ADC thing" Hobbs

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Lasse Langwadt Christensen 3 years ago

there must be bits miswired, missing, or shorted

it never recovers, after the glitch the slope/gain/offset looks different

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Phil Hobbs 3 years ago

Maybe. It's a vendor IP block that they changed around for us, to make the floor plan long and skinny. All of the bits seem to be changing independently, though. I'll check for supply current glitches if the problem is reproducible on another chip.

Cheers

Phil Hobbs

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Klaus Vestergaard Kragelund 3 years ago

I cannot get enough instruments. Can you share a link to the one you have?

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Phil Hobbs 3 years ago

It's actually 24 MHz, I misspoke. If you search Amazon for logic analyzers and sort by price, there are about 20 very similar to these ones. AFAICT they all have that same Nordic chip in them.

Cheers

Phil Hobbs

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Three Jeeps 3 years ago

agreed, but a name would save a lot of inference....

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Flyguy 3 years ago

You can sort out the riff-raff by searching for "64 channel". This eliminates most, if not all, of the low end logic analyzers. For instance, I found:

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Lasse Langwadt Christensen 3 years ago

something like this:

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Phil Hobbs 3 years ago

Dunno exactly--I didn't buy them.

Cheers

Phil Hobbs

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Klaus Vestergaard Kragelund 3 years ago

Nice, thanks. And even a Danish site, only 100km from my location :-)

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Arie de Muijnck 3 years ago

Or like this, exactly what Phil describes:

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They actually run a bit faster than 16 Msample/s, I get about 24 Msample/s. They go for less than EUR 10, including shipping. I have two, just in case I blow up one.

Arie

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