What a $20 logic analyzer looks like

delroy666

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I just scored this HP 1630D on eBay. The starting bid was $19.99 and I was the only one to bid on it!

bYu80.jpg


I had been looking for one of these units for a while, since I had been using a cheapo 8-channel USB logic analyzer. It works and all the pods and cables were included. Shipping price was good too, since it was located relatively nearby in Toronto. It's not often I find great deals like this, so I felt the need to brag. :p
 
Good deal!

Can you provide some info about the cheapo 8 channel USB one you used?

... Altan
 
How exactly are the "pods" set up? Are they just connectors with wires? Or do they have any electronics in them?

I've seen a number of cheap logic analyzers on Ebay that don't have the probes with them, but if all they are is plugs then I might take a chance at hacking one to use different connectors (probably standard 25-pin) and home made probes. Also I notice a few use crappy 3.5 floppy drives to boot, so I wonder if they could be upgraded to use one of the USB floppy emulators?
 
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You can get a really cheap 16 channel thing at http://www.seeedstudio.com/depot/preorder-open-workbench-logic-sniffer-p-612.html?cPath=75

It's basically an FPGA with some buffers. You need a PC to run it, but it's pretty darn useful for a lot of stuff. It's also freaking TINY. I've got one and it's nice for a lot of things.

That looks very cool!

Any experience with it? How long (in seconds) does the 16k buffer last?

Does someone make a case to put it in? I'd surely short it out eventually this way.

... Altan
 
That looks very cool!

Any experience with it? How long (in seconds) does the 16k buffer last?

Does someone make a case to put it in? I'd surely short it out eventually this way.

... Altan

I've used it a few times, and I hot-melt glued some cardboard to the bottom to keep from doing too much damage (I really should build a box around, but I'm kinda lazy). The software takes me a bit of bumbling around in each time I try to use it, and it's triggering isn't as rich as the HPs, but I eventually remember how to set the thing up correctly and I get the job done. It did a good job for me when I was completing my understanding of the EL panel controller on the NEO-GEO, and I've used it for work a few times (I work from home and so if I really need to know what's going on with hardware I/O, I'm kind of on my own).

The length of time for the buffer depends on the rest of your settings - at a given sample rate the buffers are smaller than what you'll find in HP analyzers, but not too shabby.

16K samples @ 200 MHz is 0.00008 seconds (that's 80 microseconds).
16K samples @ 100 Mhz is 0.00016 seconds (160 microseconds)
16K samples @ 10 Mhz is 0.0016 seconds (1.6 milliseconds)
16K samples @ 1 Mhz is 0.016 seconds (16 milliseconds)

For most older arcade systems, you don't need to sample at the real high rates (if the clock on the system is 1Mhz, then 4Mhz sampling is going to allow you to see the clock itself pretty well, and everything else will be SLOWER that the clock, and therefore 4Mhz will be just fine).

8 channels is really enough for much of what we do, but 16's even better for some stuff. The board can SAMPLE 32 channels, but only 16 channels have buffers (and connectors). You'd have to do some work and add some chips to make it do 32 signals.
 
Thanks. I'll stop hijacking this thread and, perhaps, start a new one.

... Altan
 
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