This article describes how to obtain and use the Distribution Package for Android of the STM32MPU Embedded Software for the STM32MP2 family (STM32MP25 boards) development platform, in order to modify or add pieces of software, and to create the right Android distribution for the targeted product.
It lists some prerequisites in terms of knowledge and development environment, and gives step-by-step instructions to download and install the STM32MPU Embedded Software packages for this Package.
1. Distribution Package content
If you are not familiar with the STM32MPU Embedded Software for Android distribution and its Packages, please read the following article:
In summary, this Distribution Package provides:
- An Android build framework (aka distribution builder)
- For the OpenSTDroid distribution (development on Arm Cortex-A processor):
- the BSP (Linux kernel, U-Boot, TF-A, OP-TEE) pieces in binary (prebuilt). Several scripts are provided to load source code and re-build them
- the application frameworks (including hardware abstraction code) pieces in source code
- For the STM32Cube MPU Package (development on Arm Cortex-M processor), all pieces of software in source code: BSP, HAL, middlewares and applications
- A toolset to tune the system for your needs, and to handle the built image (for example STM32CubeProgrammer to install the built image on the board).
2. Prerequisites
2.1. Knowledge
The STM32MPU Distribution Package aims to create an Android distribution for the targeted product: solid knowledge of Linux and Android are recommended to make the most of this Package.
The STM32MPU distribution for Android is an Android distribution based on the Android build framework: a short introduction about Android is available in AOSP[1].
Reading the STM32MPU Embedded Software for Android architecture overview is also highly recommended.
2.2. Development setup
The recommended setup for the development PC (host) is specified in the following article: PC prerequisites.
Whatever the development platform (board) and development PC (host) used, the range of possible development setups is illustrated by the picture below.
The following components are mandatory:
- Host PC for cross-compilation and cross-debugging, installed as specified above
- Board assembled and configured as specified in the associated Starter Package article
- Mass storage device (for example, microSD card) to load and update the software images (binaries)
The following components are optional, but recommended:
- A serial link between the host PC (through Terminal program) and the board for traces (even early boot traces), and access to the board from the remote PC (command lines)
- An Ethernet link between the host PC and the board for cross-development and cross-debugging through a local network. This is an alternative or a complement to the serial (or USB) link
- A display connected to the board, depending on the technologies available on the board: DSI LCD display, HDMI monitor (or TV) and so on
- A mouse and a keyboard connected through USB ports
Additional optional components can be added by means of the connectivity capabilities of the board: cameras, displays, JTAG, sensors, actuators, and much more.
3. Installing the STM32MPU distribution for Android
The installation relies on the repo command. If the Repo tool (a Google-built repository management tool that runs on top of Git) is not already installed and configured on the host PC, refer to the PC prerequisites article.
Create a working directory for the distribution (we recommended using the distribution name):
mkdir <working directory> cd <working directory>
1- Initialize repo in the working directory:
repo init -u https://github.com/STMicroelectronics/android-manifest -b refs/tags/<Tag> -m stm32mp2droid.xml
With
- <Tag> = tag selecting the required version of the STM32MPU distribution for Android™ (see following table)
| OpenSTDroid distribution | ||
| Tag | android-<version> | Release note |
| st-android-13.0.0-2024-07-31 | android-13.0.0_r82 | st-android-13.0.0-2024-07-31 release note (v5.1.0) |
2- Synchronize the local project directories with the remote repositories specified in the manifest:
repo sync
This may take time to get back all sources.
4. Local mirror
It can be of interest to create a local mirror of the different repositories used.
There are two possible kinds of cache:
- REPO mirror: mirror of list of modules in repositories based on provided manifest (for example Android AOSP)
- GIT mirror: mirror of one module (for example Linux kernel)
4.1. REPO mirror
It's mainly used to mirror the Android AOSP sources.
1- Create and go to the cache directory
mkdir <PathToRepoCacheDir> cd <PathToRepoCacheDir>
2- Mirror the required sources
case AOSP sources needed for the required version (recommended)
repo init -u https://android.googlesource.com/platform/manifest -b <Tag> --mirror repo sync -q
case full AOSP sources
repo init -u https://android.googlesource.com/platform/manifest --mirror repo sync -q
3- Create environment variable for this cache directory
export CACHE_DIR=<PathToRepoCacheDir>
 Information
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It's recommended to add this line also in your .bashrc file available in your HOME directory
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4- Use the cache directory
Add --reference=$CACHE_DIR option to your repo init command.
repo init --reference=$CACHE_DIR -u https://github.com/STMicroelectronics/android-manifest -b refs/tags/<Tag> -m stm32mp2droid.xml
4.2. GIT mirror
While the distribution has been installed, a helper script cachesetup is available for this purpose, which creates / updates the mirrors based on the configuration file device/stm/<STM32Series>/scripts/cache/android_cache.config.
Take care that if you change the environment variable name, you have to adapt the associated scripts load_xxxx available in device/stm/<STM32Series>-xxxx/source directory.
Create the mirrors by executing the following commands:
source build/envsetup.sh
cachesetup --new
Regular updating of your mirror is recommended by executing:
cachesetup
For more information on how to use this command, look at the cachesetup usage (execute cachesetup -h).
| Information
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It's possible to update the AOSP or the Android REPO mirror using the command cachesetup aosp or cachesetup android
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5. Building the OpenSTDroid distribution
When the installation is complete, please refer to the How to build OpenSTDroid distribution page to learn how to build it.
6. Flashing the built image
When the distribution has been built, please refer to the How to populate boards for Android page to learn how to flash your device.
7. References