PWM: Fade LED

Overview

This is a sample app which fades a LED using PWM.

The LED will start from dark and increases its brightness gradually for 10 seconds. Then, the brightness reduces gradually for 10 seconds and finally the LED becomes dark again. The LED will repeat this cycle for ever.

Wiring

Nucleo_F401RE, Nucleo_L476RG

Connect PWM2(PA0) to LED

Nucleo_F103RB

Connect PWM1(PA8) to LED

Nucleo_L496ZG

No special board setup is necessary because there are three on-board LEDs (red, green, blue) connected to the Nucleo’s PWM.

Hexiwear K64

No special board setup is necessary because there is an on-board RGB LED connected to the K64 PWM.

nrf52840_pca10056

No special board setup is necessary because there is an on-board LED connected.

Arduino 101

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.

Building and Running

This sample can be built for multiple boards, in this example we will build it for the nrf52840_pca10056 board:

Using west:

west build -b nrf52840_pca10056 samples/basic/fade_led
west flash

Using CMake and ninja:

cmake -B build -GNinja -DBOARD=nrf52840_pca10056 samples/basic/fade_led
ninja -C build
ninja -C build flash