| 摘要 |
A semiconductor integrated circuit is provided with a terminal functioning as a port terminal and a pulse circuit terminal, a port mode control register for storing data designating whether the terminal should function as the port terminal or the pulse circuit terminal, a port register for holding data to be externally output, a pulse circuit for outputting a pulse signal, a selector for supplying one of the outputs from the port register and the pulse circuit in response to the value held in the port mode control register, and a switching circuit coupled to the selector and set by a signal for writing data in the port register, for causing the selector to select the output from the port register regardless of the output from the port mode control register. When a voltage of the terminal is fixed to a predetermined voltage independent of a level of the output signal from the pulse circuit, predetermined data is written in the port register, and the switching circuit causes the selector to select the output from the port register.
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