Hello again,
and thank you for your posts, it is a big motivation for me to continue with this project, when I see more and more people involved in my project. Some posts were about the compilation on linux platform. I can’t remember exactly, but the script “arm_linux/Makefile” and necessary changes in “common/build.mk” were done by some guy here on this forum. When I am looking again to these files, it seems there are some errors like wrong slashes, and so on… Unfortunatelly I am not keeping the linux build scripts up to date, because I don’t have a linux machine to test it. It maybe needs some light changes, so if someone finds out what to change to get it working, please let me know, or push me a request on github with your changes.
About the line ending. I thought that github autmatically changes the line endings to linux style when committing the files to the server. Maybe it does not know what to do with “.hex” files. So again, if you have any idea how to fix this problem, let me know… Installing a windows virutal machine just for compiling the source codes is stupid (sorry for this word). After all gcc was initially developed for unix platform, not for windows
I am currently working on the calibration process, during the weekend I have made a lot of measurements to find out what will be the best approximation algorithm for correcting the ADC values. Yesterday I made some graphs to review these measurements, but something went wrong and for negative voltages I get incorrect values. If you are interested, here is a screenshot:
and here is an interactive view of this graph:
http://pub.valky.eu/calibbad/meas9mage.html
Every curve represents different Vpos setting (from -20 to 280), on the horizontal axis there are voltages from -2.0 to +2.0 with step 0.1V. On the horizontal axis there is measured ADC value. These ADC values were calculated as average of full sampled waveform.
I am still having problems to understand, why the negative voltages are measured incorrectly. I used RIGOL signal generator as voltage source. I was changing the voltage offset of sine wave with amplitude set to minimum (it did not allow to set the amplitude to zero, but it was under 0.4mV or so). This DC voltage was measured accurately with UNI-T digital multimeter. And this voltage was connected with the A channel probe of DSO.
Maybe it has something with the ground loop…
To answer your question, no currently there isn’t any way to calibrate the oscilloscope from the application. After I finish initial measurements and I will find a good correction algorithm, I will prepare a calibration application. But this app will be implemented probably in html/javascript with the use of DSO SDK, due the lot of calculations in floating point arithmetics.
gabriel