Hi. I'm a beginner in DSP. I want to use tones to turn GPIO pins HIGH or LOW. It looks like it would be good to employ DSP to achieve this. I've been directed towards the ADAU1701 product, but it could be that another one is more suitable. But, for now, lets stick with the ADAU1701. I've downloaded SigmaStudio so I can mess about.
I believe the technique I should be employing is to filter the signal (a set of discrete tones at about 18Khz - only one present at any moment). Now, what filter should I be using? A bandpass filter? I was thinking of having 100hz between tones. Not sure how realistic this is. If I can be given a heads up on the filter type I can start messing about. Thanks.