For this project we used a STM32-F4 discovery board, equipped with a display and a joystick shield by Funduino. The project was to program a Space Invaders game to run on this hardware. Therefore the freeRT – operating system was used as a foundation for a multitasking program. As part of the project, the game has to support single player and multiplayer as well. For the multiplayer game two boards are connected via UART. Here a protocol for the connection has to be implemented, for both boards to communicate with each other.