Before opening the Arduino software, wire up the Arduino according to the circuits page using the 8MHz minimalist breadboard circuit but with a 10k pull-up resistor on the reset pin (physical pin 1).

Many of us know the basic Blink Arduino sketch, or have coded similar routines on other microcontrollers. Flashing an LED on and off—it doesn’t get much simpler than that. But how big should a blink ...