Hi,
I am making the design of a audio product that may be connected to stereo + mic earphones. I have to detect if a button on the earphone cable (used to control volume, mute microphone, answer, etc ...) has been pressed.
These 3 BTNs are
1) VOL+,
2) VOL-,
3) mulit function (Play/pause, next track, previous track answer ...)
This kind of earphone has a 3.5 mm stereo plug with 4 pins : GND, HPL, HPR, MIC.
I think that to detect btns, impedance can be measured, but I am not sure. I have to do this with a AIC3204 codec (or perhaps AIC3104/5). Any idea about the way to detect these btns, or to measure impedance ?
Thanks.
Nicolas
