Abstract: A data storage device using SDRAM as data storage unit is disclosed. The data storage device of the present invention comprises a SDRAM controller is used to control one or more than one SDRAM. According to an aspect of the present invention, a plurality of SDRAM is stacked over each other to form stacked SDRAM structure for increasing the storage capacity. The data storage device of the present invention is capable of continuously and accurately storing and retrieving data, and it is highly resistant to vibrations. Further, the data storage device of the present invention is capable of reducing the manufacturing and maintenance cost.

Abstract: A converting circuit, for preventing wrong error correction code from occurring due to an error correction rule during data reading operation is provided. When the flash memory controller writes all 0×FF data into the flash memory, the byte error correction rule generates a set of correct error correction codes and the error correction code converting circuit converts the set of correct error correction codes into 0×FF error correction codes, and values stored in the data area and error correction code area of the flash memory are converted into 0×FF to prevent wrong error correction code from occurring during data reading operation when the error correction codes are not completely 0×FF.

Abstract: A pen drive is described. The pen drive has a control chip, a flash memory controller, at least one flash memory and a USB, a wireless wide bandwidth local network module and an antenna module. The pen drive can connect to a host equipped with a USB, such as, a notebook computer equipped with USB. This allows the host not only to save or retrieve data (or command) to or from the flash memory, but also allows the use of wireless wide bandwidth local network module to link to a wireless wide bandwidth local network. Thus, the pen drive can store data of the host, as well as allows the host to link to the wireless network allowing the user to enjoy the convenience and value added features.

Abstract: A scramble circuit for protecting data stored in a read only memory is provided including an initial value generator, a shift register, a logic circuit, an adder and a lock circuit. In said scramble circuit, the initial value generator is used to generate an initial value. The shift register is used to selectively load in the initial value and the data stored in the read only memory. The logic circuit is used to process the data stored in the shift register to generate an output transmitted back to the shift register. The adder is used to add the data stored in the read only memory and the data stored in the shift register having the same lengths, so as to obtain scrambled data. The lock circuit is used to output or lock the scrambled data according to a lock signal.

Abstract: A key switch system for switching in a cyclic pattern between a plurality of wireless communication apparatuses of a computer, comprising a function key, mounted on the computer, for generating an interrupt signal after depression; software for activating and deactivating the wireless communication apparatuses according to the signal, with one activated at a time; and a display window for displaying the activated/deactivated status of the wireless communication apparatuses; wherein cyclic switching between the wireless communication apparatuses are enacted by the depression of the function key; the wireless communication apparatuses include incompatible ones; and the cyclic pattern follows the sequence of, firstly, activating in turn each one of the apparatuses in a round and then, secondly, deactivating all of the apparatuses after a round is finished and starting another round.

Abstract: A measuring instrument includes a casing served as a rule, an angular level secured in a central portion of the casing having a rotational protractor rotatably mounted in the level for measuring any angles, a horizontal gauge provided in a right side portion of the casing for checking a horizontality, a vertical gauge formed in a left side portion of the casing for checking a verticality, a reelable plummet provided in the casing and protruded outwardly for checking a vertical line or plane, a measuring tape wound in the casing and pulled outwardly for measuring a length, and a protractor template rotatably secured on the casing having a plurality of guide slots of many geometric shapes punched in the template for guiding the drawing of many geometric shapes and having a plurality of angular graduations circularly formed on a pivotal portion of the template also for measuring planar angles, so as to provide a measuring instrument having multiple measurement uses.