Abstract: The present invention is an error detection system for liquid crystal display (LCD) devices. The system comprises a photo-scanning device coupled to a computer and a LCD display driver. Faulty LCD cells are detected by using the photo-scanner to produce two images. The first image is produced by displaying a predetermined pattern on the LCD device. This pattern is inverted to produce the second image. By analyzing these two images, faulty LCD cells are located. The results of the analysis give the location of the faulty LCD cells.

Abstract: A video display apparatus for composing video signals for a raster scanned display on a line-by-line basis. Objects are stored in a video RAM and are packed in the RAM without regard to their location on the display. A separate dispatch table contains information on each object and commands. A dispatcher operates on this information, allowing lines of data and commands to be extracted from the RAM as each video line is composed in a buffer.

Abstract: A computer monitor stand is described having a platform for holding the computer monitor, a swivel piece and a base. The platform is coupled to the swivel piece. The swivel piece is coupled to the base. The base allows the swivel piece to rotate in a certain predetermined rotational angle. The swivel piece allows the platform to vary its angle of inclination. The platform is dynamically adjustable but still statically latching. The platform has a convexly curved bottom and a rack on that bottom; the bottom fits into a concavely curved top of the swivel piece. The concavely curved top includes a cantilevered pawl which engages the rack on the bottom of the platform.

Abstract: A system for programming an asynchronous logic cell and a two- or three-dimensional array formed of such cells. Each cell comprises a number of exclusive-OR gates, Muller C-elements and programmable switches. The logic cell is reprogrammable and may even be reprogrammed dynamically, such as to perform recursive operations or simply to make use of hardware which is temporarily idle. Programming is accomplished by setting the states of the switches in each cell. A user-friendly programming environment facilitates the programming of the switches. The programming system facilitates the construction of circuits, circuit modules, black box elements and the like, with provision for storing such building blocks in a library for future reference. With an adequate library, custom hardware can be designed by simply mapping stored blocks onto chips and connecting them together.

Abstract: An enhanced video graphics controller for converting digital signals to a video signal is described. The controller is capable of displaying composite or analog RGB colors as well as providing shades of grey on monochrome displays. The processing of graphics information includes arranging 256 colors into 16 palettes of 16 colors each and is stored in a first memory. Pointers are assigned to each scan line of a frame of a display and these pointers are also stored in the first memory. Data fields which represent bit mapped video data are also stored in the first memory. For each scan line, a corresponding pointer is selected and this pointer selects one of the palettes to be loaded into a second memory. Then data field for that scan line address the second memory to provide color to the stored video data.

Abstract: A crosspoint encoder having a n-key rollover data collection system in which all keystrokes are recognized. A phantom key detection routine detects phantom key conditions and provides for temporary storage of subsequent keystrokes until the phantom condition is removed thus ensuring uninterrupted recordation of all keystrokes.

Abstract: An improved method and apparatus for converting a serial bit stream representative of a composite color video signal to RGB control signals is described. A sliding window is used to determine the video color for each new bit in the stream after the bits are rearranged to their proper order. As soon as a change in color is detected, the prior color is used until a predetermined condition occurs such as the passage of a predetermined number of bits. This prevents displaying of transitional colors which appear as shadows on the display.

Abstract: A memory mapping unit which permits a computer to run programs designed to provide 32-bit or 24-bit address signals to address a 32-bit addressable memory. When a CPU generates a 32-bit address, that address is passed through to provide a 32-bit physical address. However, when the CPU generates a 24-bit address, the most significant bits are processed by the memory mapping unit to provide a remapped 32-bit physical address. The memory mapping unit is implemented on a single semiconductor chip using gate-array technology.

Abstract: A disk drive which includes an automatic parking brake for retaining the driver arm in a predetermined position when power is removed from the disk drive. The brake is mounted externally to the driver arm, reducing the weight of the driver arm. The brake consists of a spring loaded member held in place during operation of the disk drive by a solenoid acting as an electromagnet. When power is cut off, the solenoid releases the member and the spring biases it against the driver arm and forces the driver arm to a parked position.

Abstract: An enclosure having an improved seam for inhibiting passage of electromagnetic radiation through the enclosure is described. The enclosure having a housing and a removable cover are joined at its respective edges. A plurality of spaced-apart tabs extend from an edge and slideably engage a plurality of slots which are formed on an interior surface adjacent to a corresponding mating edge. A domed projection on each tab slides into recessed cavities located on each slot to form a tight mechanical connection. The enclosure has a metal-coated interior surface and mating surface, wherein the tabs and slots operate to electrically couple the cover to the housing.

Abstract: A floppy disk drive controller interface implemented as an integrated circuit on a single semi-conductor chip. The controller connects to a host computer data bus and one or more floppy disk drives. Based upon clocking and control signals received from a digital computer, the controller generates serial encoded data for recording on a floppy disk and receives serial encoded data previously recorded on a floppy disk. The controller comprises a read control circuit including a read data register, write control means including a write data register, a mode register, a status register, state latches, a decoder and special function registers. The controller operates by the setting and clearing of the state latches and reading or writing the mode register, the status register, the special function registers, the read data register and the write data register. The setting of a state latch and accessing of a register is done simultaneously.

Abstract: A circuit for accepting serial data from a source meant for video display and displaying it on a liquid crystal display. The data is converted to parallel and is stored in address locations corresponding to four quadrants of a display screen. An input counter controls the writing of data to the memory, while an independent output counter controls the reading of data from the memory and its display on the liquid crystal screen display.

Abstract: A disk drive which includes an actuator motor whose magnets and iron path are mounted on the arm assembly to act as a counter weight. The coil of the actuator motor is mounted to the base of the disk drive with the iron path disposed around the coil and the iron core disposed through the center of the coil and all are mounted on the iron path and face the coils. By utilizing the iron path and magnets as a counterbalance, the total mass of the arm is reduced, reducing the inertia of the arm and of the power requirements of the actuator motor to move the arm.

Abstract: A local area network is disclosed including apparatus and methods for transferring data between a plurality of data processing resources ("agents") coupled to a cable. In the preferred embodiment, a plurality of agents are coupled to a common cable for data transmission and reception. An agent newly coupled to the cable dynamically assigns itself a unique address on the cable to which other agents may send data. Once an agent has been assigned a final address, it may then transmit to, and receive data from, other agents on the cable. An agent desiring to send data to a receiving agent follows a three step handshake, wherein the sending agent transmits an "RTS" signal and within a predetermined time must receive a "CTS" signal from the receiving agent. The sending agent then transmits a data frame within a predetermined time after the CTS signal is received. The failure to detect a return CTS signal within the predetermined time denotes a collision condition.

Abstract: A cursor control device having particular application to a computer display system is disclosed. The cursor control includes a unitary frame, having a domed portion substantially surrounding and retaining a ball which is free to rotate. X-Y position indicating means are provided, such that rotation of the ball provides signals indicative of X-Y positions on the display system. The ball is free to "float" in the vertical direction within the dome, and thereby maintain good surface contact. X-Y positions are established by movement of the control device over a surface. A display system and method is disclosed for use in conjunction with the cursor control device, which permits a user to select command options simply by movement of the displayed cursor over a "pull-down" menu bar.

Abstract: A cursor control device having particular application to a computer display system is disclosed. The cursor control includes a unitary frame, having a domed portion substantially surrounding and retaining a ball which is free to rotate. X-Y position indicating means are provided, such that rotation of the ball provides signals indicative of X-Y positions on the display system. The ball is free to "float" in the vertical direction within the dome, and thereby maintain good surface contact. X-Y positions are established by movement of the control device over a surface. A display system and method is disclosed for use in conjunction with the cursor control device, which permits a user to select command options simply by movement of the displayed cursor over a "pull-down" menu bar.