Mitsubishi Denki Kabushiki Kaisha

Fumitaka Fukuzawa

Shunichi Iwata

Takashi Nasu

A microcomputer comprises a serial interface for receiving a debugging program applied thereto from a debugging tool, a register for holding an instruction code included with the debugging program, which is applied to the microcomputer via the serial interface, and a central processing unit or CPU for executing the instruction code held by the first register to debug the microcomputer. The microcomputer can further comprise a buffer for holding one or more instruction codes supplied thereto from the register. The CPU can execute each of the plurality of instruction codes held by the buffer. Preferably, the serial interface is a JTAT (Joint Test Action Group) interface.

Microcomputer which can execute a monitor program supplied from a debugging tool

A microcomputer of the present invention permits a direct control of a rewrite operation on an internal flash-memory to enhance the efficiency of a debugging operation. The microcomputer has a first storage means that stores a program for rewriting data into an internal flash memory, a second storage means that stores internal flash information about the internal flash memory, an interface that makes a connection to a debugging tool, and a CPU. The CPU allows reading of the internal flash information by the debugging tool through the interface, receiving of write data based on the internal flash information from the debugging tool through the interface, and rewriting of the write data as new contents into the internal flash memory in accordance with the program for rewriting data into the internal flash memory.

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Tokyo, Japan

Fumitaka Fukuzawa