| 摘要 |
<p>PURPOSE:To effectively utilize an output latch as a pull-up register by providing a pull-up resistance control circuit controlled with the outputs of a direction register and the output latch. CONSTITUTION:In a single chip microcomputer, an output latch 3 holding data from an internal data bus 6 by an output latch writing signal and an output buffer 4 outputting the data of the output latch 3 to an input/output terminal 1 are provided. A direction register 5 controlling the operation or non-operation of the output buffer 4 and an input buffer 2 inputting the data of the input/ output terminal 1 to the internal data bus 6 are provided. A control circuit 7 controlling the presence or absence of the pull-up resistance by the contents of the output latch 3 and the direction register 5 is provided. Thus, the output of the output latch 3 can be utilized as the control register controlling the presence or absence of the pull-up register at the time of setting input.</p> |
