Spin Semiconductor

I have been trying to rework slacker's tap tempo code to use one of the ADC inputs for the switch. I have been able to get it it work-ish, for the most part anyway. I feel that if I had more info on how the ADC is read vs the POT inputs then things would be much easier.

I see in the manual that the POTs are read with 10bit resolution and range from 0 to 0.999 while the ADCs have 24bit resolution and range from -1 to +0.999. I have observed that the input sits at a nice 1.65V and doesn't seem to fluctuate at all regardless if there is signal present or not. I am assuming this is to get the full 3.3V peak-to-peak of headroom. And of course the POT inputs range from 0 to 3.3V depending on where the potentiometers are set.

I guess my real question is what exactly is the ADC reading in terms of voltage and how does changing this voltage change how the signal is read, if at all?

The ADC input is biased to a mid level which is the 1.65 volts you are seeing. The real problem is the ADC expects an AC signal while a switch provides a DC signal, as a result it will do what you are seeing in that it may sort of work.

Bottom line is the ADC inputs are not designed for DC level reading and you really need to use a POT input. Also the POT inputs have low pass filtering to help get rid of noise, the ADC inputs have high pass filtering to remove DC.

Just to further my understanding, the FV-1 utilizes delta-sigma ADC architecture?

Yes they are delta-sigma