> You count the time that it takes for the paddle bit to go from low
> to high. When you write a 1 into bit 7 of VBLANK the pots will be
> discharged and the paddle read bits will go low. When you write 0
> into bit 7 of VBLANK the pots will start to recharge. The further
> you have turned a paddle's knob the longer it will take to recharge
> the paddle's pot and the longer it will take the paddle's read bit
> to go high again.
This is completely correct from a programming point of view, but just a
couple minor electrical nitpicks... "Pot" is short for potentiometer,
which is a variable resistor and is pretty much all the paddle is. (The
pots don't discharge or recharge.) When you write the 1 into bit 7 of
VBLANK, a capacitor in the console gets grounded and drained. It stays
grounded until you write a 0 to that bit. Then, it starts recharging
through the potentiometer; the paddle read bit will go high when that
capacitor is fully recharged. How long it takes to recharge is determined
by how much resistance the paddle's potentiometer is currently supplying,
and that's how you get the paddle's position.
Eckhard is completely correct from the software end, though, so feel free
to ignore all of this if it confuses you :)
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