An electronic control unit having a microcontroller provided with RAM associated with variable data and ROM associated with the code of a software operating system incorporating a real time core for executing computer tasks. The RAM and ROM include zones corresponding to partitions, one of which is allocated to the real time core, while each of the others is allocated to at least one of the tasks. The RAM and the ROM are associated with an address bus that is physically programmed so that each partition is prevented firstly from writing in another one of the zones of the RAM, and secondly from executing another one of the zones of the ROM. The real time core is associated with a timer for allocating an execution time to each partition.