| 摘要 |
PURPOSE:To change the setting of the number of priority levels and the allotment of levels to each interruption in an extremely simple way, by reducing the storage area of an RAM, etc. which is used as a stack area. CONSTITUTION:The occurrence of interruption requests INT0-INT15 is informed by rising the signal lines of these requests to a high level. When a masked-off interruption request is supplied to a highest rank detecting circuit 12, the circuit 12 selects the request having the highest priority among those having the permission for acceptance. On the other hand, the information of 3 bits corresponding to the priority of the highest interruption request INT'15 is delivered from the circuit 12. The priority level information given from the circuit 14 is stored in a priority level register 16 with a certain timing when the interruption is accepted. |
