In a memory controller, a serial data including an instruction bit train with addition of a start bit, a clock signal, a chip enable signal, and a reset signal are inputted. During the active period in which the chip enable signal is being inputted, the serial data is stored depending on the clock signal and an enabling signal is generated based on the end timing of active period. Thereby, memory access is executed depending on contents of the instruction bit train. However, when the relevant apparatus is reset during the active period, generation of the enabling signal based on the end timing of the active period is inhibited.