Trying out software cap-sense

[mmoskal]

This is raw, low-level API. To be tested and higher level ones to be built.

[mmoskal]

Can be done in TS, probably need to drop this PR.

let v = 0
let t = 0

function cap(p:PwmPin) {
    p.digitalWrite(true)
    p.setPull(PinPullMode.PullNone)
    p.digitalRead()
    control.waitMicros(50)
    return p.analogRead()
}

game.onPaint(() => {
    let n= control.millis()
    if (n-t>400) {
        t=n
        v=cap(pins.P0)
    }
    screen.print("v:" + v, 3, 3, 3)
})