Disclosed herein is an LSI apparatus having a CPU and a plurality of functional blocks for controlling an external equipment, the plurality of functional blocks sharing one external terminal connected to the external equipment, including: a mode register having a flag information set by the CPU indicating validity or invalidity of each functional block; a selector for switching the connection between each functional block and the external terminal; and a switch controller retaining a priority sequence among each functional block, for controlling switching of the selector based on the priority sequence and the flag information set at the mode register.