Abstract: In a data transmission apparatus for transmitting data between a main system and a microcomputer a controller generates transmission control signals based on first control signals received from the main system, and a memory system receives the transmission control signals and second control signals from the microcomputer. The memory system transfers data between the main system and the microcomputer based on the transmission control signals and the second control signals.

Abstract: A data transmission apparatus for transmitting a data between a main system and a microcomputer which can apply to the system the microcomputer which is not provided with a logic circuit performing an interface with the main system, sense both the main system and microcomputer by using an error sensing bit to sense a problem in transmission, and improve a transmission speed of the system by increasing a size of the data to be processed at one time, includes: a signal controller sensing the data transmission and outputting first and second transmission control signals; a data transmission detector communicating the data transmission to the microcomputer according to the first control signal from the signal controller; and a double buffer latching the data for a predetermined period in order for the main system or microcomputer to read through a corresponding port the data to be transmitted according to the first and second transmission control signals from the signal controller, and a method thereof.

Abstract: An apparatus for moving a cursor finely on a screen moves the cursor in an application program such as a CAD that requires high accuracy. The apparatus includes a mouse button formed at a predetermined portion of a mouse for selecting data; fine movement buttons formed to predetermined portions around the mouse button for moving a mouse cursor upward, downward, left and right by a preset value; and a fine movement interval regulator formed to a predetermined place of the mouse button for providing a fine movement signal per preset time while a user presses the fine movement button.