I 'm working on a project building a recorder with WM8731 that record sound from MICIN, using ADC to handle it , then pass to DAC and feed Lineout. I tried DE2_MEDIA_COMPUTER and the effect of play-back is awesome. But after I copied the original code to my NIOS2 project and build it, it turns out to be a failure. I can record sound like DE2_MEDIA_COMPUTER but can only lasted for about 4 secs( which is almost 10 secs in DE2_MEDIA_COMPUTER) and there exists considerable background noise there. What's the problem?
I've figure out how to make a high-quality recording of MICIN inputs finally. i'll share with u. Just use interrupt from AUDIO CORE to handle the data stream by calling HAL in UP core provided by altera. The sound quality is fabulous. If you use the reference design from altera's Media Computer, you'll find the quality quite disgusting. Just change to code, and use interrupt. It'll work out fine