DAC Output Problem

[eglaser]

Hello,

I have wired my Quixote so that the DSP Timer 2 (DIO pin 47), External ADC Start Trigger (pin 48), and External DAC Start Trigger (pin 49) are all connected. My DacStream and AdcStream objects are both setup with an appropriate FramedTmb timebase. DacStream.Buffer is filled up with a simple waveform.

I have separate input and output threads. The output thread is very simple; it basically just calls DacStream.SetDefaultImage(), then DacStream.PlayDefaultImage(), then Sleep(SYS_FOREVER).

Once the DSP Timer is enabled, i can see the output waveform on a scope hooked up to the DAC0 port. However, after some time (a few seconds to a few minutes) the output disappears. My input thread is still running fine, but for whatever reason, the output waveform stopped playing.

Do you have any ideas what could be causing this? I built a trivial example based on the AnalogOut sample and that seems to play fine for as long as the board is powered. My application has a good amount of processing (FFTs, filters) and host communication, but the output thread shouldn't be affected by that as far as I can tell.

Any help is greatly appreciated.

Thanks,

Eli

[jhenderson]

Try commenting-out portions of your processing code until your application degenerates into something similar to the vanilla AnalogOut example. Along the way, I suspect you'll find an offending code fragment that may be trashing the output thread, or the Default output image used by that driver.

Have you debugged the output thread to determine whether it stops Put()ing buffers? If so, the object is probably getting trashed. If not, only the image is being affected.

Track to the processing code to the point where the timer or the Output thread cease operating.