COMMUNICATION SYSTEM AND ELECTRONIC CIRCUIT

A communication system includes an I2C device, an SPI device, a selection circuit and an electronic circuit. The selection circuit selects the first data signal when the CS signal is not received, and generates a signal corresponding to the CS signal and transmit the CS signal to the SCL terminal as the stop signal and at the same time. The selection circuit selects the second data signal when the CS signal is received. The electronic circuit functions as a slave of the SPI communication in a case where the CLK signal has made a transition. The electronic circuit further functions as a slave of the I2C communication in a case where the CLK signal does not make a transition and signals indicating a condition under which the I2C communication is started are transmitted to the CS/SCL terminal and the data terminal.