Microcomputer including program for rewriting data in an internal flash memory

A microcomputer comprising:

• a first storage means that stores a program for rewriting of an internal flash memory;
• a second storage means that stores internal flash information with respect to the internal flash memory;
• an interface that makes a connection to a debugging tool;
• and
• a CPU, wherein
• the CPU allows
• execution of debugging based on an instruction code of a debug program held in a first register by the debugging tool through the interface in conjunction with holding internal flash information stored in the second storage means in a second register so that the internal flash information is readable by the debugging tool through the interface, and
• a rewrite operation in which write data based on the internal flash information held in a third register is written into the internal flash memory in accordance with the program for rewriting data into the internal flash memory by the debugging tool through the interface.