| 摘要 |
PURPOSE:To establish increased memory space for many data if necessary by accessing the data memory space of an additionally established memory device by using the input-output port of an existent memory device. CONSTITUTION:To access additionally established memory device 15, address signal C regarding address memory 11 for the additionally established memory is sent from CPU1 to address signal discriminating circuit 3, which supplies address discrimination signal D as a trigger signal to storage 11. At this time, address data E sent from CPU1 to memory 11 is latched in storage 11. On the basis of address discrimination signal F supplied from circuit 3, data E is read out with control signal G generated by control signal generating circuit 13 for the extended memory and addressed as address discrimination signal H to the corresponding data memory space of device 15 via address discriminating circuit 14. Therefore, data are transferred between the data memory space of device 15 and CPU1 via data bus 16. |
