This is a sample app which blinks a LED using PWM. The LED will start at a blinking frequency of 0.5Hz. Every 4 seconds, the blinking frequency will double. When the blinking frequency reaches 500Hz, the blinking frequency will be halved every 4 seconds until the blinking frequency reaches 0.5Hz. This completes a whole blinking cycle. From now on, the LED will repeat the blinking cycle for ever. Arduino 101 and Quark D2000 CRB =========== You will need to connect the LED to ground and PWM0 via the shield. You may need a current limiting resistor. See your LED datasheet.