AD2 + DWF on Raspberry Pi using C# (.NET 5)

[Andras]

Hi,

I have a very basic .NET 5 based C# console application that opens the Analog Discovery 2 using the DWF.cs wrapper class included in the WaveForms SDK v3.15.5 (64-bit) on Windows.

I could install the .NET 5 runtime on my Raspberry Pi 4 B, and I could run other .NET apps on it without any issues.

I created a small application that opens my AD2 and starts acquiring data from its CH1 input.

It runs as expected on Windows 10, but when I run it on the 32-bit Raspberry Pi OS I got the following error:

Unhandled exception. System.DllNotFoundException: Unable to load shared library 'dwf.dll' or one of its dependencies. In order to help diagnose loading problems, consider setting the LD_DEBUG environment variable: libdwf.dll: cannot open shared object file: No such file or directory
   at dwf._FDwfGetVersion(StringBuilder szVersion)
   at dwf.FDwfGetVersion(String& szVersion) in /home/pi/Work/BioBalanceDetector/Measurements/WaveForms/Experiments/SleepLogging/csharp/SleepLogger/dwf.cs:line 212
   at SleepLogger.Program.Main(String[] args) in /home/pi/Work/BioBalanceDetector/Measurements/WaveForms/Experiments/SleepLogging/csharp/SleepLogger/Program.cs:line 17

Is there a way to install the missing DWF DLLs or their Linux/Raspberry alternatives on my Raspberry Pi and make my app work?

I have WaveForms 3.14.3 (32-bit) already installed on the Raspberry Pi.

[attila]

Szia @Andras

The WF (application and runtime) is available for Linux ARM32 (armhf) and ARM64 (arm64):
https://reference.digilentinc.com/reference/software/waveforms/waveforms-3/start

For Linux you could try changing in the dwf.cs wrapper the DllImport("dwf.dll" to DllImport("libdwf.so" or DllImport("dwf.so" or DllImport("dwf"
... Sorry but I'm not familiar with .Net on Linux

[Andras]

Szia @attila,

I fixed the C# wrapper, now it works on both Windows and Linux and I corrected two method signatures in that file, please find it attached.

I played around with the Record function (using the FDwfAnalogInStatusRecord method) on my Windows desktop and on Raspberry Pi 4. I used .NET 5 and C#, so my actual source code is identical on both platforms.

I noticed that as I raised the sampling rate, I started to get corrupted recordings above a certain sampling rate. On Windows I could reach 1 MHz, but the highest value was only 125kHz on the Pi.

I also tested this with WaveForms and I got the same results, so I suppose it's a hardware limitation. I also realized that I could potentially double the maximum rate if I could change the mode of my AD2 to the one that have 2x16k buffer for the scope. Is there a way to change to that mode programmatically using DWF?

dwf.cs

[attila]

Szia @Andras

Thank you for the dwf.cs observation. 

See the following post:

 

[Andras]

Excellent, thanks @attila!