Abstract: A device for sharing a memory of a microcontroller with an external device is provided. The device according to the present invention includes a communication unit for exchanging information between the external device and the memory, a bus controlled circuitry for exchanging information between CPU of the microcontroller and the memory. The bus control circuitry is also adapted to generate CPU status signals. The device for sharing a memory space of a microcontroller further includes memory arbitration circuitry, coupled to the communication unit and to the bus control circuitry, for receiving the CPU control status signals and responsive to this signals operatively coupling the communication unit to the memory when the CPU status signals indicate that the CPU will not access the memory for a predetermined time.