| 摘要 |
A machine, for example, a document copier is controlled by a microprocessor. A number of the machine elements are controlled by data from corresponding add-on memory modules (106, 107). In operation, these modules are accessed in sequence to retrieve data to control operation of the corresponding machine elements. Each add-on memory includes a flag (33) which when set, or not set, respectively indicates whether the corresponding machine element is essential or inessential of operation of the machine. When an add-on memory is accessed, its data content is checked, if it is invalid the flag is then checked. If the flag indicates the corresponding machine is essential, then the machine is stopped, otherwise the next add-on memory is accessed. |
