| 摘要 |
PURPOSE:To reduce the occupied time of a main bus for communication of a sub-CPU by providing a register to give an indication of start to the sub-CPU from a main CPU. CONSTITUTION:A sub-CPU2 is always reading a command register 5 through a sub-CPU local bus 8 while waiting for a command given from a main CPU1. When the CPU1 needs to give processing request to the CPU2, the CPU1 prepares a command name and data at a main memory 3 and sets ''1'' to the register 5. Thus the CPU2 uses a main bus to read the memory 3 and then uses a local memory 4 to execute the requested work. When this processing is over, the CPU2 writes the processing result to the memory 3 and also writes ''1'' to an interruption register 6 to give an interruption to the CPU1. Thus the end of the processing is informed. While the register 5 is reset as soon as ''1'' is written to the register 6. |
