| 摘要 |
PURPOSE:To output and read data efficiently by providing a RAM area accessed by a common address and an output port. CONSTITUTION:In the case where output data are such that a CPU 150 does not need to know, data are outputted by using an I/O 140. When outputted data are such that the CPU 150 needs to know, the CPU 150 sends a write signal to a write signal line 170, and gives a command to write the data on a n address. Thereby, the data are stored in the n address of a RAM 120 through a data bus 160, and at the same time, sent to an output port 130 of the n address. When it is intended to know the data sent out, the CPU 150 sends a read signal to a read signal line and gives a command to read data. Thereby, the output data stored in n address of the RAM are read out, and sent to the CPU 150 through the data bus 160.
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