| 摘要 |
<p>PURPOSE:To decide a state of a signal input/output terminal by an electronic device itself, by inputting a data to be outputted and a data which appears actually in the signal input/output terminal, into the electronic device through the first and the second selecting circuit, respectively. CONSTITUTION:In case of a data output control to a signal input/output terminal 40, AND of a register address number ADR1 which is allocated to a mode register 10, and a write control signal WR is taken by an AND circuit 11, and an output signal of the AND circuit 11 is inputted as a write clock to the mode register 10. Whether a state of the signal input/output terminal 40 is an output state or an input state can be determined by the mode register 10. At the time of input, which data is to be inputted into a microcomputer is selected by a selecting gate 53 by using the respective address numbers ADR2 and ADR3.</p> |
