| 摘要 |
PROBLEM TO BE SOLVED: To attain communication via both a serial port and a shared memory without changing the software for communication of a CPU board for control at all. SOLUTION: A CPU board 11 for control is mounted on an extended bus slot 14 of a personal computer 12, and provided with a shared memory 13 accessible from a CPU 17 side of the personal computer 12. A CPU 15 at the CPU board 11 side for control operates communication through the serial communication hardware 30 by interrupting processing 27. At the time of the interrupting processing 27, information stored in a buffer 20 ensured on the shared memory 13 is used. At the time of transmission processing 28 and reception processing 29, the information stored in the buffer 20 is processed. Even when the storage of information is directly from the personal computer 12 side to the buffer 20 of the shared memory 13, the CPU board 11 side for control is allowed to operate the transmission processing 28 and the reception processing 29 in the same way as the interrupting processing 27.
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