Open Source Logic Analyzers? 29
Rorschach1 asks: "I'm a hardware hacker, doing my part to develop useful open source projects, but my projects are getting more ambitious and my test equipment just isn't keeping up. PC based oscilloscopes have been discussed here before, but I'm particularly in need of a logic analyzer. The BitScope does offer an 8-channel analyzer with Linux support, but that hardly compares to most commercial offerings. I'm also concerned by the fact that I can't find any independent reviews of the device, and I'm hesitant to shell out $500 without knowing what I'm getting into. A logic analyzer is a pretty simple device. My current setup runs on a dedicated 486 with ancient DOS-based software. Surely there must be a more modern option available that'll work under Linux, but so far I've been able to find nothing. Perhaps someone can point me in the right direction?"
found via google (Score:1, Interesting)
Re:found via google (Score:2)
Re:found via google (Score:1)
Ask a better question... (Score:4, Insightful)
Sometimes I think that all you need to get your question in "Ask Slashdot" is to preface it with "I'm looking for an open-source blah blah blah..."
Re:Ask a better question... (Score:4, Informative)
Something that could look at a data line and clock line and give me a hex dump of the data would be nice, but I don't really need any more intelligence than that.
Re:Ask a better question... (Score:2)
Re:Ask a better question... (Score:2)
I guess I shouldn't complain. This time it only came out sounding poorly defined. Last time my question just sounded stupid.
Look at this project... (Score:4, Interesting)
Check out his Carmon project if you're interested in long term GPS data tracking (stores a GPS data stream to a compact flash card)
-Adam
Re:Look at this project... (Score:2)
Re:Look at this project... (Score:2)
-Adam
Re:Look at this project... (Score:2)
Yup. And and this [pipercubforum.com] is the same as this [boeing.com].
And and this [shoptheplace.com] is the same as this [fas.org].
(all links safe for work)
BTW: This is only for laughs.
But on a serious note, a modern FPGA can have a LOT of extra goodies on board, such as hardware multipliers, embedded dual-port RAM and FIFOs, PLLs, and even pro
Whatever you do... (Score:2, Funny)
On a semi-related note (Score:3, Interesting)
It had been a while since I shopped for this stuff and I happily found that Agilent (used to be HP) has what they call "mixed signal scopes". Specifically, we purchased a 54622D. It's 100MHz 2 channel oscillscope, but then it's also got a 16 channel logic analyzer built in. (See full specs here [testequity.com].) We purchased it used for around $2600. To get that price we had to play two of the used dealers against each other a little bit. We have been really happy with it so far. $2600 is quite a bit more than $500, but you do get both a scope and a small logic analyzer for that... It's got a built in serial interface and floppy, and it's more portable than dragging a computer around. Take care, and good luck with your quest!
Re:On a semi-related note (Score:2)
Re:On a semi-related note (Score:2)
Comment removed (Score:4, Insightful)
Timing? (Score:2)
You'll probably only be able to get timing resolution near that of the OS tick interrupt interval, right? Sounds like the makings of a piss-poor logic analyzer.
I suppose if you were using an open source OS kernel, one where you could change the OS tick interval -- you might be able to make use of your logic analyzer idea.
Re:Timing? (Score:3, Informative)
Only if you do it using a hardware resource under control of the OS and do polling. Even the parallel port can generate interrupts to the OS. Add a microcontroller and/or some custom hardware and the OS doesn't come into play except for display.
You can do your own with a FPGA easy (Score:3, Informative)
Anything more than 10-20mhz you are going to have to buy something though.. although I never did tests to see how fast or reliable my hacked apparatus was.
Go ebay hunting. Lots of deals on there.
Re:You can do your own with a FPGA easy (Score:1)
I am now currently developing an microcontroller with an CPLD type logic analyser, still in its breadboard stage and it contains:
- DS89C420, Fast 8051 derivative from maxim-ic, its available for free as part of their excellent sample program. (free)
- 32K 10ns SRAM's out of an 80486 mainboard. (free from a mainboard)
- Several 74F244 bus drivers. (F logic for high speed) But maybe would b
I thought these sounded pretty cool... (Score:3, Interesting)
http://www.rockylogic.com/products/ant16.html [rockylogic.com]
HP 1631D (Score:3, Interesting)
The oscilloscope channels have limited voltage swings, but are good enough for most of the work I have done. You can always build/purchase dividers to measure higher voltages.
If you do get a 1631 or something similar, make sure it has the pods and test clips. They get pretty expensive to purchase/replace.
Dean
Cheapest Logic Analyzer? Heh, got you all beat! (Score:4, Interesting)
With some level shifting circuitry you can turn any common RS232 serial port into a 4 channel logic analyzer. It you've got +5 volt TTL levels, you can probably get away without any extra circuitry.
Say what?!
Yep. Most anyone can do this. In my case, I went so far as to write a device driver that makes it work under Windows NT/2K/XP. It hooks the serial ports interrupt service routine and logs the state of the UART's modem status register or MSR. Four bits from the MSR tell us the state of the CTS, DCD, DST, and RI input pins. I use the RDTSC instruction which offers ridiculous accuracy (theoretically, it's the CPU's clock speed) compared to most other software based solutions - even betten than some coarse-grained hardware solutions.
The same could easily be done under Linux or anything with a serial port and Pentium compatible processor.
I never thought anyone would be interested so no website or anything. Interested persons can send me an email ...
mailto:rfmobile@swbell.net
-rickRe:Cheapest Logic Analyzer? Heh, got you all beat! (Score:2)
*sigh* Typo ... sorry, that's the CTS, DCD, DSR, and RI input pins.
-rick