| 摘要 |
PURPOSE:To eliminate an access competition by determining an access right to a dual port memory according to the state of a flip-flop. CONSTITUTION:The flip-flop 34 is set by a CPU 11, and reset by a CPU 21. When it is confirmed that the state Q of the flip-flop 34 becomes L, by a state detecting circuit 37, and it is known that the access right to the dual port memory is obtained, the CPU 11 writes a message to the CPU 21, in the dual port memory. The CPU 21 which knows that the terminal Q becomes L, by a state detecting circuit 38, and secures the access right executes the read processing of a message from the CPU 11, and writes a result in the dual port memory.
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