Abstract: A disc recording and reproducing device and method record video data using a new file system other existing device cannot recognize. However, when a disc thus recorded is loaded in the existing device, the user is prevented from being instructed to format the disc (initialize the file system) or inadvertently erasing data thereon. The disc recording and reproducing device comprises the following elements. A first write-enable state setting unit checks a write inhibit flag when a disc is loaded, and sets the flag on the disc to a write-enable state when the flag is in a write-protect state. A first write-protect state setting unit checks information in a record history information storage when the disc is unloaded, and sets the flag on the disc to the write-protect state when data is recorded thereon or the flag in the memory is in the write-protect state and no data is recorded.

Abstract: A disc recording and reproducing device and method record video data using a new file system other existing device cannot recognize. However, when a disc thus recorded is loaded in the existing device, the user is prevented from being instructed to format the disc (initialize the file system) or inadvertently erasing data thereon. The disc recording and reproducing device comprises the following elements. A first write-enable state setting unit checks a write inhibit flag when a disc is loaded, and sets the flag on the disc to a write-enable state when the flag is in a write-protect state. A first write-protect state setting unit checks information in a record history information storage when the disc is unloaded, and sets the flag on the disc to the write-protect state when data is recorded thereon or the flag in the memory is in the write-protect state and no data is recorded.

Abstract: A microprocessor includes an assign function for assigning ports to a mode identifying unit, test signal input unit, and test result signal output unit, a test implement function for sending test results to the test result signal output unit according to the test data signals input from the test signal input unit, and an activation control function for activating the test implement function upon identifying a test mode by the status of the mode identifying unit. When a test mode signal from test equipment is received at the test mode identifying unit assigned to one port of the microprocessor, the test signal input unit and the test result signal output unit are assigned to other ports of the microprocessor, and when the test data signals from the test equipment are received at the test data signal input unit, test result signals according the test data signals are output from the test result signal output unit.

Abstract: An external expansion bus interface circuit is provided for connecting a peripheral to a micro control unit to exchange digital information under an external expansion memory mode of the micro control unit. For this purpose, the eternal expansion bus interface circuit includes a means for storing a writing data. Address decoder and a strobe decoder are connected to the micro control unit to directly receive the writing data, an address strobe, and a write strobe. Then the address decoder and strobe decoder produce a write enable signal for enabling the memory to store the data at address designated thereby.