I have been delving (groping blindfold, more accurately) into the Arduino compiler adaptation code to try to determine how it handles the switch-over between its pwm activities, its set-I/O-to-output ...

Comprising a microprocessor, an LCD, a 32.768-kHz crystal, and little else, the basic countdown-timer circuit in Figure 1 operates from a commonly available CR2032 lithium-coin-cell battery. Based on ...