60 second timer countdown
Count down from the number specified by the max_count variable. Button A restarts the timer when expired. Button B restarts the timer at any other time. Pressing B when the timer has expired, however, changes the smiley displayed. In this case it is set to 60. The number scrolls across the LED display, so the time taken to scroll must be accounted for. Once we reach single digits (now able to display them on the LED array) scrolling stops and the numbers are displayed statically. A smiley indicates the timer has expired. This remains until the timer is restarted by pressing A.