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The values are read in from the various sources in either of two ways.
The two-terminal resistance of the joysticks, the "wheels" and the auxiliaries with a tricky "discharge a capacitor and count how long it takes to get back to a threshold voltage" charge-timing circuit A la IBM game port {see also Apple ][ and later}; the digital inputs just feed into a shift register and are clocked in.
The Innovation First program just sucks it all in, and blows it all out in a programmed order which avoids having two successive bytes of 255 (see the PBasic argument thread). The RC input program takes the bytes in, in the same preprogrammed order, and then passes the user-selected (CON = 1) bytes to the Stamp, in the order ordained in the SERIN statement.
Can you mess with it ? no. Should you mess with it ? NO! It is because it is so "out-of-your-hands" that you may have such wide latitude in your choice of input controls. Nothing can go wrong.*
* explanation
refers to a joke from the age of Dinosaurs: the airplane PA system comes on: "Good Afternoon, Ladies and Gentlemen. This is a recording (on a disk with grooves - pre Jurassic). This airplane has no pilot. Through the Wonders of Modern Science, a computer will fly this airplane from takeoff to landing. Nothing can go wrong ..putt! (as the needle ships back a groove).. Nothing can go wrong ..putt..!"
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