| 摘要 |
PURPOSE:To shorten a testing time and to grasp the cause of a trouble concretely by handling I/O ports as memories to test the I/O ports under the status a microcomputer is mounted in a system and connecting a resistor and an integrating circuit to the microcomputer. CONSTITUTION:When the microcomputer is to be tested under the mounted status on the system, an input port 13a is connected to a sensor 21 through a resistor 40 and an output port 13b is connected to a transistor (TR)32 through the integrating circuit 50. When prescribed data are to be written in the port 13a at a testing time, the resistor 40 can interrupt the influence of the data even if the sensor 21 is ON. When the prescribed data are written in the port 13b, the data does not exert influence upon the TR32 for a prescribed period. Since the ports 13a, 13b are tested as memories and the resistor 40 and the circuit 50 are connected, the testing time can be shortened and the cause of a trouble can be concretely grasped. |
