Ok so the propeller microprocessor has 32 Input/output ports. That is 32 wires from the CPU that can connect to other circuits. Now with a pinball machine project that uses many lights to make it look pretty, solenoids for the playfield, a video screen that I may use up to 4096 LEDs with, plus all the sound/music. 32 ports are simply just not enough.
So the solution is to use an Integrated Circuit (little black plastic chip with pins sticking out of it) called a Shift-Register. Basically it takes the serial signal from 1 single port from the CPU and splits it up to 8 outputs. So my next project was to make a 24 LED chaser circuit. Which worked flawlessly.
Next project …to get a shitload of LEDs together to make a video screen.