COMMUNICATION PORT CONTROL DEVICE OF MICROCOMPUTER FOR VEHICLE

摘要

PURPOSE: A device for controlling a communication port of a microcomputer of a vehicle is provided to promote the use of a microcomputer by using two communication ports via one microcomputer. CONSTITUTION: A microcomputer(20) continuously outputs active low and high signals and response data upon input of active high signals. First and second communication ports(21,22) outputs request signals and discharges the response data to an external device. A first transfer(23) outputs the request signal applied from the first communication port and transfers the response data to the first communication port. A second transfer(24) outputs the request signal applied from the second communication port and transmits the response data to the second communication port. A selector(25) transmits the response data to the request signal to the first and second transfers. Since the request signals are selectively transmitted to the microcomputer by the selector and the response data corresponding to the request signals are selectively discharged to the first and second communication ports, two communication ports are used by one microcomputer.