Abstract: Data in a write request (RE1) transmitted by a processor (PR) to a read/write controller (CM) must be written in a non-volatile memory (MNV) in a portable electronic object, such as a smart card. An application can be executed in the processor simultaneously with the writing of the data in the memory in response to an acknowledgement (AC) indicating the availability of the controller for writing. However, another write request transmitted before the end of the writing is put on standby until the end of the writing. The controller also provides a verification of integrity of the data to be written in the memory.