| 摘要 |
<p>A franking machine is disclosed in which the accounting memories are implemented by memory devices (15, 16) in which each storage location comprises a volatile and a non-volatile cell. During normal operation data is written to the volatile cells of the storage locations and in the event of a power down the data is transferred from the volatile to non-volatile cells. The volatile cells preferably are semi-conductor and the non-volatile cells are ferreoectric capacitative devices which retain their polarisation without supply of power. The memory devices may provide storage for accounting data and other data processed by a micro-controller (10) of the franking machine. In addition the memory device (15, 16) may be utilised to store other data which is not to be processed by the micro-controller. Such data includes program data. In order to prevent such data being erased or over-written gating circuits (32) are provided to prevent write accesses by the micro-controller to areas of memory utilised for storing data which is not to be changed. <IMAGE></p> |
