zephyr

History

Sebastian Bøe 55ee53ce91 cmake: Prepend 'cmake_minimum_required()' into 'app' build scripts Prepend the text 'cmake_minimum_required(VERSION 3.8.2)' into the application and test build scripts. Modern versions of CMake will spam users with a deprecation warning when the toplevel CMakeLists.txt does not specify a CMake version. This is documented in bug #8355. To resolve this we include a cmake_minimum_required() line into the toplevel build scripts. Additionally, cmake_minimum_required is invoked from within boilerplate.cmake. The highest version will be enforced. This patch allows us to afterwards change CMake policy CMP000 from OLD to NEW which in turn finally rids us of the verbose warning. The extra boilerplate is considered more acceptable than the verbosity of the CMP0000 policy. Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>		2018-08-15 04:06:50 -07:00
..
src	…
CMakeLists.txt	cmake: Prepend 'cmake_minimum_required()' into 'app' build scripts	2018-08-15 04:06:50 -07:00
README.rst	…
prj.conf	…
sample.yaml	…

README.rst

.. _blink-led-sample:

PWM: Blink LED
##############

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
******

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.

Nucleo_F401RE, Nucleo_L476RG, and STM32F4_DISCOVERY
===================================================
Connect PWM2(PA0) to LED

Nucleo_F103RB
=============
Connect PWM1(PA8) to LED

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

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: arduino_101
   :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