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# Blinky Mbed OS example

The example project is part of the [Arm Mbed OS Official Examples](https://os.mbed.com/code/) and is the [getting started example for Mbed OS](https://os.mbed.com/docs/mbed-os/latest/quick-start/index.html). It contains an application that repeatedly blinks an LED on supported [Mbed boards](https://os.mbed.com/platforms/).

You can build the project with all supported [Mbed OS build tools](https://os.mbed.com/docs/mbed-os/latest/tools/index.html). However, this example project specifically refers to the command-line interface tool [Arm Mbed CLI](https://github.com/ARMmbed/mbed-cli#installing-mbed-cli).
(Note: To see a rendered example you can import into the Arm Online Compiler, please see our [import quick start](https://os.mbed.com/docs/mbed-os/latest/quick-start/online-with-the-online-compiler.html#importing-the-code).)

## Mbed OS build tools

### Mbed CLI 2
Starting with version 6.5, Mbed OS uses Mbed CLI 2. It uses Ninja as a build system, and CMake to generate the build environment and manage the build process in a compiler-independent manner. If you are working with Mbed OS version prior to 6.5 then check the section [Mbed CLI 1](#mbed-cli-1).
1. [Install Mbed CLI 2](https://os.mbed.com/docs/mbed-os/latest/build-tools/install-or-upgrade.html).
1. From the command-line, import the example: `mbed-tools import mbed-os-example-blinky`
1. Change the current directory to where the project was imported.

### Mbed CLI 1
1. [Install Mbed CLI 1](https://os.mbed.com/docs/mbed-os/latest/quick-start/offline-with-mbed-cli.html).
1. From the command-line, import the example: `mbed import mbed-os-example-blinky`
1. Change the current directory to where the project was imported.

## Application functionality

The `main()` function is the single thread in the application. It toggles the state of a digital output connected to an LED on the board.

**Note**: This example requires a target with RTOS support, i.e. one with `rtos` declared in `supported_application_profiles` in `targets/targets.json` in [mbed-os](https://github.com/ARMmbed/mbed-os). For non-RTOS targets (usually with small memory sizes), please use [mbed-os-example-blinky-baremetal](https://github.com/ARMmbed/mbed-os-example-blinky-baremetal) instead.

## Building and running

1. Connect a USB cable between the USB port on the board and the host computer.
1. Run the following command to build the example project and program the microcontroller flash memory:

    * Mbed CLI 2

    ```bash
    $ mbed-tools compile -m <TARGET> -t <TOOLCHAIN> --flash
    ```

    * Mbed CLI 1

    ```bash
    $ mbed compile -m <TARGET> -t <TOOLCHAIN> --flash
    ```

Your PC may take a few minutes to compile your code.

The binary is located at:
* **Mbed CLI 2** - `./cmake_build/mbed-os-example-blinky.bin`</br>
* **Mbed CLI 1** - `./BUILD/<TARGET>/<TOOLCHAIN>/mbed-os-example-blinky.bin`

Alternatively, you can manually copy the binary to the board, which you mount on the host computer over USB.

## Expected output
The LED on your target turns on and off every 500 milliseconds.


## Troubleshooting
If you have problems, you can review the [documentation](https://os.mbed.com/docs/latest/tutorials/debugging.html) for suggestions on what could be wrong and how to fix it.

## Related Links

* [Mbed OS Stats API](https://os.mbed.com/docs/latest/apis/mbed-statistics.html).
* [Mbed OS Configuration](https://os.mbed.com/docs/latest/reference/configuration.html).
* [Mbed OS Serial Communication](https://os.mbed.com/docs/latest/tutorials/serial-communication.html).
* [Mbed OS bare metal](https://os.mbed.com/docs/mbed-os/latest/reference/mbed-os-bare-metal.html).
* [Mbed boards](https://os.mbed.com/platforms/).

### License and contributions

The software is provided under Apache-2.0 license. Contributions to this project are accepted under the same license. Please see [CONTRIBUTING.md](./CONTRIBUTING.md) for more info.

This project contains code from other projects. The original license text is included in those source files. They must comply with our license guide.