| 摘要 |
<p>PURPOSE:To drive and monitor the load via a single port of a microcomputer by providing a load monitor circuit, a load monitor feedback circuit, a current direction detecting circuit, and an output drive circuit. CONSTITUTION:A load monitor feedback FB circuit 23 outputs the FB voltage of a high level while a load monitor circuit 22 is detecting the increase of the load voltage and feeds the FB voltage back to a microcomputer 10. A port input circuit 13 of the microcomputer 10 decides a high or low level of the FB voltage based on the proper input threshold value. If the output voltage of a port output circuit 11 has a high level under such a condition, a current I+ flows to a load driving circuit 20 form the microcomputer 10. A current direction detecting circuit 24 detects the directions of currents I+ and I- and controls an output driving circuit 21. As a result, the load can be driven and monitored via a single port of the microcomputer 10.</p> |
