Micro controller development system

The present invention relates to a development of a semiconductor chip; and, more particularly, to a micro controller development system (MDS) capable of helping a development of hardware and related software of a micro control unit (MCU). The present invention relates to a micro controller development system (MDS) capable of helping a development of hardware and related software of a micro control unit (MCU). The micro controller development system according to the present invention includes: a micro controller including first and second data I/O ports; a memory unit for storing commands for a program to be transplanted to an internal code ROM in the micro controller; a switch for transferring address signals to the memory unit in response to a first control signal and for transferring the commands from the memory unit to the micro controller in response to the first control signal, wherein the address signals are transferred via the first data I/O port and wherein the commands are transferred via the second data I/O port; a first I/O interface unit for performing data input or output between the first data I/O port and a single data port of an external device in response to a second control signal; and a second I/O interface unit for performing data input or output between the second data I/O port and the single data port external device in response to the second control signal.