Products > Test Equipment

SainSmart DDS120 & DDS140 USB Oscilloscope

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mmark:

--- Quote from: doctormord on November 13, 2014, 01:46:01 am ---
--- Quote from: psynapse on November 12, 2014, 10:08:22 pm ---Doctormord

That is very strange, I can decompress both my original local copy of scope2.zip and a copy I just downloaded from this board;

--- End quote ---

Well, downloaded again and get the same errors on the same files on linux and windows. (Even on C:\ .. )

--- End quote ---

FWIW: I could download and unzip scope2.zip without any issues on my mac... And after changing the .pro file a bit I was able to compile and run it as well, but had no time to add support for the DDS120 yet, but will hopefully in the next few days.

doctormord:
@ganzuul,

i actually get this, when starting the app.

Possible solution:

http://qt-project.org/forums/viewthread/22908

Edit:

I'm on Win7 32bit.

ganzuul:
Our cooperation so far has proven itself an obvious strength. We've been screaming along at supersonic speed and consequently it's difficult to tell at this point which way we are going.

The vagrancies of the Win32 version of OpenHantek can be hidden away within the .pro file, and right now the project is otherwise identical to mmark's. The actual code base compiled without alteration once the correct compiler/qmake combo was unlocked. That's why it's quite interesting that stop/start works on Windows but not on Linux.
We don't seem to have a functioning trigger. It ought to be possible to make one in software that behaves like a Schmitt trigger. With some scaling and adaptivity this in turn would easily lend itself to frequency counting. For that stuff we'll probably have to rely on an FFT library.

Miscellaneous thoughts:
I have had the FX2 dev board in my Aliexpress shopping cart for a while now too, and I have been learning a lot about electronics. I have ideas for data acquisition hardware modules which I hope to explore. An FX2 talking with an FPGA or CPLD is a great and versatile combo that the DDS120 avoids with the skin of its teeth.
Gnuradio has a scope built-in, along with its uncountable other features. Its GUI is based on WX. The developer community is quite helpful and there is lots of documentation. They are well-versed in DSP and bridge out to an academic, industrial and even military audience. The code-base is huge though, and far from portable.
For heavy-duty compute, GPUs seem to beat FPGAs. FPGAs excel in high-throughput with light compute situations and the latest generation of entry-level FPGAs from Xilinx and Altera have high-speed Ser/Des at low cost. For GPU documentation and education, nVidia's has more. For FOSS, one has to choose OpenCL. If a laptop just a few years old has trouble with FFTs, we might want to consider some rudimentary OpenGL/OpenCL interop to alleviate that. 


------

doctormord,
On it!

ED:

https://nya.dy.fi/secure/Ledioskope.zip
user: eevblog
pass: eevblog

CRC32: EE3DAF51
MD5: 6D5F867C992EF571A0824202BC863221
SHA-1: 09FF567F9936E4A820EB5C267B81064BECB31CFE

Server SSL SHA-256: 8F:42:26:3D:09:F2:2D:5B:1E:CB:CE:04:5E:9F:B4:50:70:E7:B8:40:82:83:BB:B2:FF:24:49:70:85:D9:4D:F4

doctormord:
And.. it's working!  :scared:

Thanks alot, now i'll go to bed.  :-+

Edit: From Start i got CPU-load of 90+%, but then, somehow, it droped to ~8%.

Can't reproduce for sure, but it seems like there's something with the trigger settings.


System is a C2D 6750 @3GHz 4GB, NVIDIA GFX..

psynapse:
Doctormord

I will dig out a windows machine later today and see if I can replicate the problem on that.  All I did was use the Ubuntu archive manager to zip up the directory .......  And do not judge my coding skills on what is in the ZIP, it is a mess!  More objectively perhaps you should judge my coding skills by what is in the ZIP!  Seriously, it is just a vehicle for trying out ideas and not debugged bomb proof code.

Ganzuul,

I agree, and it is good to know that there is a close convergence between your code and that of mmark.  I have the feeling that the easiest thing I can do is to ride on the coat tails of you two, though I still have my doubts about the openhantek code.

I do have a functioning trigger in software (though only in my adaptation of Donut6 WX based code).  It is based on generating the first differential of the input data (more simply the difference between current and previous input value) .  By keeping track of the maximum of this value and where it occurs in the dataset you have a plot startpoint.  To speed the process and to avoid late syncs which leave too little data to plot, I scan just the first 25% of the input in this way.

Later today, I shall be wiring Int5 to the external socket of the DDS140 and writing a small ISR to allow Int5 to generate a "go code".  This will give an external trigger to the device, limited only by the fact that data acquisition will start a few microseconds after the trigger pulse.  The ISR could equally invoke a stop code, but I am no longer certain that stop really does stop the device!  I think we need to work on that to get a clean end state (ie one which does not pollute the start of the next capture, something we are all seeing at the moment.  BTW , what I thought were FIFO flush commands seem to trash the DDS140)

MMark,

Glad the code worked for you. I would not worry too much about developing it ... It was really a vehicle for showing some ideas (I have since added the variable timebase stuff and plan on doing the Int stuff as soon as family obligations permit).  I am very happy to "go with the flow" (you and Ganzuul) as long as I can expand the code to get hardware triggering in and the variable timebase stuff.  However, I did like the pan and zoom on the display,  which is basically my mash of other peoples code.  And if I really get really stuck, I will steal your good ideas and support for the DDS120 and put them in my code, with your permission of course.  How goes the firmware?

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