| 摘要 |
PURPOSE:To transfer data with a small quantity of hardware, by supplying the address of a slave input/output control device, where the access should be started, from a CPU to a master input/output control device. CONSTITUTION:A CPU1000 initializes a mastrer input/output control device IOC 100 for read/write designation, address, and data length. The CPU1000 causes the IOC100 to issue the first bus use request signal to a bus use request signal line A1 to start the IOC100. Next, when conditions satisfy the request due to the bus use request signal, the CPU1000 transmits a bus use permission signal and an IOC designating signal to signal lines B and C respectively. The IOC100 designated by this designating signal outputs initialized read/write designation, address, read or write control signal, and IOC access signal to signal lines F, H, D or E, and G respectively. Thus, data is transferred between the IOC100 and a designated slave IOC200. |
