Semiconductor integrated circuit with voltage-detecting circuit and signal transmitting and receiving system

Abstract

A first semiconductor integrated circuit is connected to a second semiconductor integrated circuit with a cable. In the first semiconductor integrated circuit, when a power supply voltage becomes less than a set voltage detection level, a voltage-detecting circuit outputs a voltage-detected signal to lower the voltage of the cable and to stop the operation. The second semiconductor integrated circuit detects the decrease in the voltage of the cable to recognize the halt of the operation of the first semiconductor integrated circuit. In the first semiconductor integrated circuit thus configured, in testing the operation under low-voltage conditions in which the power supply voltage is less than the set voltage detection level, the voltage-detecting circuit receives a control signal from an external terminal to stop the operation forcibly. Consequently, even when the power supply voltage is made lower than the set voltage-detecting level, the first semiconductor integrated circuit properly operates until the power supply voltage reaches a predetermined lower limit of operating voltage. Thus, evaluation of operation is possible under low-voltage conditions.