[Al Skierkiewicz]

Wow,
This is an old issue. The input to the OI is a simple voltage divider where one side of a joystick pot is connected to 5 volts and the wiper is in series with a resistor in the OI. (The other terminal is not connected) As the joystick varies so to does the voltage inside the OI. The A/D convertor is scaled for this value (100K) to produce the 256 steps. The important thing to remember is that OI operation demands a return to zero (PWM=127) if the joystick should get pulled out by accident. This is the failsafe. The rule about the 100K is to insure that the joystick input tracks from joystick to joystick and allows the correct sensing in the event of a joystick failure. It is conceivable that a small value pot could be interpreted as an open joystick. As Jack has dicussed above, a change in value disrupts the A/D conversion and at the very least, does not give the maximum control/resolution that a 100K pot will give.

The common misconception of the RC circuit comes from many years ago, the robot controller (pre IFI) used the Basic Stamp. The Basic Stamp device does use the RC process to read pot values. Hence the confusion.