Oscilloscope with sound card

[juergui]

I´m an spanish student of telecommunications enginering. I´m designing an oscilloscope and a signal generator using as digital to analog interface the PC sound card.

My application has the user interface and the code that control the user events made in LabWindows/CVI 4.0.1. The sound card events (asynchronous) are controlled with a code made in Visual C++ 6.0 that is linked with the user interface by a Dinamic Link library (.dll)

Sometimes when i´m running my application a message appears telling me

"An asynchronous callback thread has caused an exception. Program will be terminated"

and the program ends. This message appears but no ever under the same conditions.


I don't know why this happens.

Could someone
get me the answer? Please i need help.

[JRA]

Since this error occurs eroneously, it is difficult to fully assess the issue. However, there are a couple of suggestions I would make for troubleshoothing this.

First, make sure that you are not writing and reading at the same time. When using multiple threads, it is possible that a race condition could arise, and you may be reading from your digital to analog card at the same time you are writing to it. This would most certainly cause an error like this.

Next, did you ever get the update for LabWindows/CVI 4.0.1? This fixed a number of bugs that were found with CVI 4.0.1. If you did not get this, I would suggest doing so now. I do not know if you can still obtain it from NI's website since 4.0.1 is a pretty old version (6.0 is the newest). However, if you c
ontact them, they can probably get a hold of it for you. Let us know what you find out.