The CHARLIE unit

Driver for "Charlie Plexing" up to 6 LEDs (3 outputs) or 12 LEDs (4 outputs).

(It would be easy to modify to use more outputs)

There's only one procedure to call: CharliePlexing; it may be called from within an interrupt procedure.

Each time the procedure is called, on LED is treated.

The procedure have to be called often enough to have a smooth rendering for the eyes.