.. _blink-led-sample:
PWM: Blink LED
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Overview
********
This is a sample app which blinks a LED using PWM.
The LED will start at a blinking frequency of 1 Hz. Every 4 seconds,
the blinking frequency will double. When the blinking frequency
reaches 64 Hz, the blinking frequency will be halved every 4 seconds
until the blinking frequency reaches 1 Hz. This completes a whole
blinking cycle. This faster-then-slower LED blinking cycle repeats forever.
Wiring
******
Nucleo_F401RE, Nucleo_L476RG, STM32F4_DISCOVERY, Nucleo_F302R8
==============================================================
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 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.
Building and Running
********************
This sample can be built for multiple boards, in this example we will build it
for the arduino_101 board:
.. zephyr-app-commands::
:zephyr-app: samples/basic/blink_led
:board: nrf52840_pca10056
:goals: build flash
:compact:
After flashing the image to the board, the user LED on the board should start to
blinking as discussed in overview
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