Microcomputer and functional evaluation chip

A microcomputer for functioning based on a plurality of operation modes comprising;

• a mode signal output unit that outputs a mode signal in accordance with a level of a mode setting signal applied to a mode setting terminal, wherein the mode signal represents one of the operation modes;
• a clock input terminal;
• a data terminal through which serial data is inputted synchronously with a serial clock signal applied to the clock input terminal;
• a serial-to-parallel conversion unit that converts the serial data into parallel data and stores the parallel data in an input data buffer;
• and
• a switching means that switches to a state that a CPU is capable of accessing to the input data buffer when the mode signal represents a test mode, wherein;
• in the test mode, test instruction data is capable of being inputted from an external circuit, and
• the mode signal output unit sets a width of a voltage range corresponding to a user mode to be larger than a width of a voltage range corresponding to other operating mode.