I'm pretty sure you can hook up your 1 wire to 1 input. That's the idea here right. What you can then do is define things that can happen in the skin which depend on that 1 inputs value.
(This is if you are using FCC Uber edition)
so you define and name an analog input, then in the logic section of the skin you can use the value of the analog input to toggle new variables, which can then be used... well, however you want
<iochannel id="SteerCom" port="1" brain="MainBrain" type="analogue_input">
initialize some variables:
This code isn't actual and you would have to go by the examples in the configuration file. I think this would have to be done in the UberFCC release, to do it in this general way. The psuedocode sucks, but I hope it puts the point across, or elicits a response from the expert.
Vol-Up = 0
Vol-Dn = 0
Ch-Up = 0
Ch-Dn = 0
Mode = 0
StrComErr = 0
if SteerCom < 4.5 & SteerCom > 3.55V
then all variables = 0
SteerCom is > 3.05V
then mode = 1 and all others = 0
SteerCom is > 2.25V
then Ch-Up = 1 and all others = 0
SteerCom is > 1.45
then Ch-Dn = 1 and all others = 0
SteerCom is > 0.75
then Vol-Up = 1 and all others = 0
else if SteerCom is > 0.2
then Vol-Dn = 1 and all others = 0
StrComErr = 1 and all others = 0
The values I chose were to split the difference between the values to minimize non-responsiveness. False positives might occur though, if so the bands could be tightened.
And the err variable could make some error message or indicator happen or even go into the log. But then you have now some digital signals (the variables) that you can use to make things happen with.
(I don't quite know how FCC will communicate to make volume change in windows, or tracks and mode for PC-radio usage yet).