| 摘要 |
PURPOSE:To set freely an optional area matching to the using condition of a shared memory by a system CPU by providing an address latch means to store the address of the shared memory and providing the common area at the shared memory. CONSTITUTION:An address latch circuit 22 is provided with a local CPU 2, and stores the address of the shared memory 3. Between systems CPU 1 and CPU 2, the common memory areas are set which both can read/write the data in the memory 3. Namely, first, the CPU 1 divides the head address of the area in the memory 3 through a common bus 4 into the lower order position and the higher order position and latches it to the circuit 22. Next, through a microprocessor 21 of the CPU 2 and an AND circuit 23, the area is determined, thereby the CPU 1 divides optimally the whole of the area of the memory 3 to areas on the processing and can be used. Consequently, the CPU 1 can freely set the common area matching to the using condition of the memory 3.
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