Software migration - Porting embedded application into a new microcontroller unit: within the STM32Fx07xx product series

This bachelor’s thesis looks at porting embedded software to an updated platform. The upgrade takes place in a monitoring and safety device resembling a motor control unit, which has a typical operating environment of industrial hoists and cranes. The device is an existing product of Konecranes. The new hardware environment, the device, is otherwise physically identical, except that the primary microcontroller is upgraded to a newer one. This happens within the STM32 microcontroller family and the process is called migration. The controllers and their peripherals are very similar. Their main difference is their core, the older one being Cortex M3 and the newer M4. The most essential benefit here is more RAM. The thesis first studies microcontrollers and software migration in general. The study found that there are not standardized methods for migration, as there are basically infinite possible scenarios. Next, the migration process was approached with general iterative development process, which was fit for migration. The process is also supported with preliminary and finishing actions, the most significant of which are defining comprehensive acceptance criteria and maintaining a consistent source tree. The practical part includes studying the differences between the mentioned microcontrollers and updating the hardware abstraction layer, which consists of processor-specific libraries and drivers. The results are studied with hardware testing, which was done with a previously implemented test application. This ensures functionality of most peripherals of the microcontroller, but not all. Thus, additional testing is required by debugging the actual user application via the serial communication of the microcontroller. After achieving barely functional user application, the development would be continued with the aid of feedback from automated test sets. Finally, the thesis theorizes how to achieve the goal of the migration process, which is stable operation of the actual embedded application in the new environment. A systematic, iterative and progressive process of trial and error is used