Abstract: A memory has a plurality of areas, anyone of which may be assigned a status from a central control unit as to whether it is writable or non-writable and as to whether it is or is not write protected. When an order to write is received, a deciding circuit indicates the status assigned to the pertinent memory area. A certain period of time is measured during which write protection may be canceled if a predetermined procedure is followed. Then the deciding circuit gives or denies writing access according to the assigned status and to whether a proper protection cancellation procedure has been followed.