Assignment 5: The Do Nothing Box.

A popular electronics project is to build a ``Do Nothing Box.'' Such a box does nothing except flash its LED's in seemingly random ways, so that you think that it is doing something, or you are otherwise amused even though you know it is doing nothing.

Your Do Nothing Box will flash the 8 LED's on the DEMBOARD is a seemingly random fashion by using a Pseudorandom number generator built from a software shift-register and a 1-bit exclusive-or.

Yours will be the deluxe model Do Nothing Box: it will have 8 speed settings selectable using the RA1 push-button. Pushing the button will switch the PIC from display random lights mode to select speed mode. If the push-button is not again pushed for a certain number of seconds, the PIC automatically returns to display random lights mode, at the current speed setting.

Entering select speed mode, one of the 8 LED's is lit, to indicate the current speed setting. The rightmost LED indicates the slowest setting, the leftmost LED indicates the fastest setting. While in select speed mode, pushing the button advances the speed one setting. Advancing past the fastest setting returns to the slowest setting.

Extra Credit: For extra credit, uses the timer and interrupts in your implementation.

Last Modified: Fri Nov 7 11:51:11 EST 1997