# Run the model on development board

## In this learning path

- [Introduction](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/tflow_nn_stcube/)
- [Prepare development environment](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/tflow_nn_stcube/setup/)
- [Collect training data](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/tflow_nn_stcube/train_nn/)
- [Train the model](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/tflow_nn_stcube/test/)
- [Feature extraction](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/tflow_nn_stcube/features/)
- [Run the model on development board](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/tflow_nn_stcube/run_nn/)
- [Next Steps](https://learn.arm.com/learning-paths/embedded-and-microcontrollers/tflow_nn_stcube/_next-steps/)

In this section, you will deploy the model directly on the STM32 board.

## Setup STM32CubeMX project

[STM32CubeMX](https://www.st.com/en/development-tools/stm32cubemx.html) is a graphical tool for configuring STM32 microcontrollers.  
[STM32Cube.AI](https://www.st.com/content/st_com/en/campaigns/stm32cube-ai.html) is an extension of STM32CubeMX to import ML models.

1. Download and install STM32CubeMX from the [STM32CubeMX product page](https://www.st.com/en/development-tools/stm32cubemx.html).
2. Open STM32CubeMX IDE.
3. Click `Access to Board Selector`. Find your `B-L475E-IOT01A` board and click `Start Project`.
4. Go to `Project Manager`. Enter a project name and select the project location where the project will be saved.
5. Under `Pinout & Configuration`, expand `Pinout` menu, and click `Clear pinouts`.
6. Expand `Software Packs` menu, and click `Select Components`.
7. Locate `X-CUBE-AI`, and click its `Install` button.
8. Expand the menu and enable `X-CUBE-AI` > `Core`. For device application, choose `Validation`. If the status shows a yellow warning, click `Resolve` to install any necessary dependencies.
9. Click `OK` when done.

## Validate the NN model

You will now validate the NN model built in the previous section on the desktop and the development board.

### Validate on desktop

1. On the STM32CubeAI menu, locate `X-CUBE-AI` configuration from the list of `Categories`.
2. click `Add network`. Browse to the generated model (`.h5` file). You can also specify other values, such as validation input, and validation output. Leave as default for now.
3. Click `Analyze`, then it will generate a detailed report on the model. You can check the number of parameters, the size of the weights, and the amount of memory to be used.
4. Click `Show graph` to visualize your model.
5. Click `Validate on Desktop` to validate the model with the provided input and output on your desktop.

### Validate on development board

To validate the model on the target, you need to first generate code and install the code on the target.

1. Click `Validate on target`, and enable `Automatic compilation and download`. Select the appropriate toolchain (`STM32CubeIDE`), and click `OK`.

## Demo with the sample application

A sample application is provided. This uses a feature-based model, trained with the letters `O` and `S` written in a horizontal plane.

**Notice**  
There is a bug in the example as supplied. You must edit `/Core/Src/main.c` before building.  
Locate the function call in `main()` to
- `MX_USART1_UART_Init()`
and move to before the call to
- `MX_X_CUBE_AI_Init()`

1. Using a terminal application (such as `PuTTY`), set up the serial connection to the board. `COM` number will be as before. The baud rate should be 115200.
2. Import the application. Click the File tab and click `Import`. Select `Existing project into workspace`. Go to `tf_stm32` folder and select `MCU_Activity_Recognition`.
3. Open `X-CUBE-AI/App/app_x-cube-ai.c`. Observe that functions are provided for data acquisition from the accelerometer sensor and feature extraction.
4. Build application and flash to target with `Run As`.
5. Observe output on the terminal.
6. Press the blue button on the board, draw a letter, then press the button again.

## Create your own application

You can create your own application from the model you have trained.

1. Open the list of Software Packages. Change the device application as `Application`.
2. Click `Generate Code` then the project is updated.
3. Open `STM32CubeIDE`. Since you re-generated the code again, you need to delete the existing project and import the project again.
4. Open `X-CUBE-AI/App/app_x-cube-ai.c`. This is the auto-generated code by `STM32CubeMX`.
5. Between `USER_CODE_BEGIN` and `USER_CODE_END`, you can write code for your application.

There are two main functions that you should implement:
- `acquire_and_process_data()` is for getting data from sensors and processing the data, for example, extracting features.
- `postprocess()` is for postprocessing the output.