Abstract: A bridge for coupling two buses together utilizes a data buffer to act as a point of synchronization to provide effective data operations between the buses. The bridge includes master and slave capability on both buses and an arbiter for selecting between requests from bus masters on one bus. The data buffer includes a number of dual ported memories for write posting and read ahead operations. Each dual ported memory is allocated to a bus master of the one bus. The bridge allows data operations to each dual ported memory based on data or space availability of the memory. Simultaneous reading and writing capability on alternate buses is provided.

Abstract: A method that identifies the type of LCD panel used in a portable computer system based on the frequency of the oscillator signal of the DC-to-AC inverter in the LCD panel. In this method, only one signal is routed from the LCD panel to the base unit of the portable computer system for the purpose of panel identification. The inverter oscillating signal is used to increment a counter during power on operations. A system counter, which is clocked by a system clock, is used to determine the number of system clocks needed for the panel identification counter to reach a predetermined count. That number is compared with the entries of a table, in which each entry corresponds to a type of LCD panel. In this manner, the type of LCD panel can be identified based on the frequency of the inverter signal. A corresponding entry in a second table is accessed to obtain a table entry for the identified LCD panel to a full table of LCD panel parameters. The table entry is stored in a predetermined location in the Video ROM.

Abstract: A page wide piezoelectric ink jet print engine and a method of manufacturing the same. The page wide ink jet print engine includes lower and upper body parts, each formed from piezoelectric material and having a plurality of generally parallel, spaced projections. Lower side surfaces of the projections of the lower body part are conductively mounted to corresponding bottom side surfaces of the projections of the upper body part to define a plurality of generally parallel, axially extending ink-carrying channels from which ink may be ejected.

Abstract: A modular computer includes a portable computer providing a first set of performance characteristics, an expansion module couplable to the bottom surface of the portable computer to provide, in combination therewith, a second set of performance characteristics, and a docking module couplable to the portable computer through the expansion module to provide, in combination therewith, a third set of performance characteristics. A method of altering the features of a portable computer includes providing a portable computer having a first set of features, operatively coupling the portable computer to a transportable base wherein the coupling provides a second set of features, and operatively connecting the portable computer through the transportable base to a stationary base, wherein the connecting provides a third set of features.

Abstract: A portable, reprogrammable printer diagnostic controller comprising a microcontroller, an EPROM for storing operational programs, a "flash" memory for programmably storing data to be used in the diagnosis of the printer, and connectors for coupling the system to both a computer for the downloading of software into the system and to a printer for downloading the stored programs into a printer for diagnostic testing.

Abstract: A notebook computer is provided with a collapsible keyboard in which a dome sheet with elastomeric key return dome members thereon is horizontally shiftable through elevation and retraction strokes to respectively shift the keys between elevated operating positions in which the domes underlie and support the keys, and retracted positions in which the domes are shifted away from their key-underlying positions. A linkage member interconnected between the computer lid and a drive bar on the dome sheet creates initial triggering movements of the dome sheet through its elevation and retraction strokes in response to opening and closing of the lid. In response to these lid-created triggering movements of the dome sheet, a bistable spring structure connected to the drive bar takes control of the dome sheet and drives it through the balance of the stroke and then releasably retains the fully shifted dome sheet in the resulting stroke end position thereof.

Abstract: A power converter which transfers energy from an output circuit coupled to a secondary winding of a power transformer to an input circuit coupled to a primary winding of the power transformer in order to reduce the power loss and electromagnetic interference (EMI) originating from a primary switch. The reciprocating action of the converter is accomplished by placing the series switched path of a secondary switch in parallel with a diode in the output circuit. A control circuit is coupled to the primary switch and the secondary switch which allows the inherent capacitance of each switch to discharge before turning on the respective switch, thereby reducing the EMI and power losses occurring at these switches. The control circuit includes feedback and feedforward voltage control of the switching duty cycle. The control circuit varies the energy transferred from the output circuit to the input circuit according to changes in the accumulated charge on the primary switch.

Abstract: An audio power management system for a computer eliminates audible noise associated with the cycling of power to an audio amplifier for a computer. A diode is connected between the power supply rail and the power input to the audio amplifier. One or more decoupling capacitors is provided at the power input to the audio amplifier to insulate the audio amplifier from fluctuations at the power supply. The apparatus mutes the amplifier for a brief period shortly after power becomes available and mutes the amplifier immediately when power is removed to eliminate transient noises. In one embodiment, the muting of the audio amplifier is accomplished by FET switches. In a second embodiment, the muting of the audio amplifier is accomplished by analog switches. Additionally, the audio power management system eliminates audible noise associated with the waking-up or putting the computer to sleep. The audio system asserts a speaker mute signal before power is removed from the amplifier to reduce transient conditions.

Abstract: A compact disc drive is mounted within a computer chassis with the rotatable spindle portion of the drive positioned inwardly adjacent an external wall of the chassis a distance substantially less than the radius of a compact disc operatively supportable on the spindle for driven rotation thereby. When a compact disc is placed on the spindle a substantial portion of the disc projects outwardly beyond the chassis during operation of the drive. In this manner, the interior chassis space required for the drive is substantially reduced. To shield the outwardly projecting disc portion during use of the drive a housing structure is carried by the chassis for movement relative thereto between a retracted position in which the housing structure is telescoped with the drive within the chassis interior when the drive is not in use, and an extended position in which the housing structure extends outwardly from the chassis and receives the outwardly projecting disc portion when the drive is operating.

Abstract: A docking base for a portable computer includes a hollow housing with a generally horizontal support portion for supporting the portable computer thereon and a generally upright portion disposed on a rear end of the support portion. The docking base further includes a connector unit provided on the upright portion of the housing. The connector unit is adapted to engage corresponding connector units on a rear side of the portable computer for connecting the portable computer to at least one computer peripheral device. The upright portion of the housing includes a front wall that is formed with a vent hole to be juxtaposed with a heat-dissipating fan unit on the rear side of the portable computer so that hot air from the fan unit can enter into the housing. The upright portion is further formed with an exhaust hole to prevent the hot air from being trapped in the housing.

Abstract: A computer system includes a display controller which supports video display. The display controller includes circuitry for determining which portions of one or more video windows should be written to the frame buffer responsive to the locations of other screen objects which may overlie the video window on the display. An unused portion of frame buffer memory is used to stored a plurality of transition groups, each group defining which portions of the video window are visible within a range of scanlines. The transition information is used by clipped circuitry to enable or disable writing of video information to the frame buffer.

Abstract: A portable notebook computer has a base housing with a keyboard structure movably supported on its top side. The keyboard structure is movable relative to the base housing between a forwardly disposed, generally horizontal storage and transport orientation and a rearwardly shifted use orientation in which the keyboard structure is upwardly and rearwardly tilted. When the keyboard structure is in its storage and transport orientation a front side portion thereof covers an underlying pointing device, representatively a trackball device. When the keyboard structure is rearwardly shifted to its use orientation it uncovers the pointing device for operation by the computer user. Due to this vertical stacking of the keyboard structure and pointing device, the front-to-rear dimension of the computer base housing may be advantageously reduced. Additionally, due to the rearwardly and upwardly tilted use orientation of the keyboard structure its user operating comfort is enhanced.

Abstract: A computer docking station has a disk drive module incorporated therein which is capable of operatively receiving a disk drive therein. The disk drive module is also capable of being operatively installed within a desktop computer or other enclosure having a half-height bay therein. Security features of the docking station include preventing access by unauthorized persons to the disk drive, and preventing ejection of the disk drive from the disk drive module. Additionally, multiple disk drive modules may be cooperatively linked in the docking station so that the security features relating to each of the disk drive modules may be simultaneously actuated.

Abstract: A computer system for communicating with a network including a host processor, memory, an interface bus and a network interface device for reducing data transfer latency between the computer system and the network. The network interface device includes a buffer for temporarily storing data, a media interface device for transferring data between the buffer and the network, a bus interface for transferring data between the computer system's memory and the buffer, and a local processor for writing a unique value at a predetermined location within the buffer, for periodically comparing the data value at the predetermined location with the unique value and for initiating data transfer from the buffer to the computer's memory when the data value does not match the unique value. The network interface device is preferably a network interface card (NIC) for plugging into a slot of the interface or expansion bus of the computer system.

Abstract: The present invention relates to the placement of signal traces on a two-sided printed circuit board such that impedance of the traces is controlled and so that the number of power and ground pins required on an integrated circuit are minimized.

Abstract: A distributed direct memory access (DMA) architecture where greater than seven DMA channels are provided and utilized. Alternative methods are disclosed for paging or swapping DMA channels so that more than seven may exist in a computer system, but only seven may be available at a time to remain compatible with conventional DMA controller software. In one method, channels may be assigned identical addresses, with one enabled at one time. In another method, channels are assigned unique addresses but the DMA master addresses only a subset of of the total number of channels so that up to seven are available to compatible software at any one time.

Abstract: A power distribution system for a multi-layer circuit board includes a board having a component layer with signal runs formed thereon, a ground layer, an insulation layer, and a power supply system. The power supply system includes a supply bus, discrete voltage supply planes, and isolation devices mounted on the component layer, each connecting one of the discrete voltage supply planes to the supply bus. The component layer has a first area for components which perform a first function and a second area for components which perform a second function. The discrete voltage supply planes include a first supply plane corresponding to the first area and a second supply plane corresponding to the second area. The first supply plane is disposed directly beneath and is shaped substantially the same as the first area, and the second supply plane is disposed directly beneath and is shaped substantially the same as the second area.

Abstract: An in-band/out-of-band alert delivery system for a computer system manager includes an alert log which maintains a record of alerts to be delivered and the status of those alerts, an alert manager for making a first atop to deliver each alert, and a retry manager for making subsequent attempt to deliver alerts as becomes necessary and appropriate. The alert delivery system may also include a bus master interface manager for making in-band alert deliveries and a communications manager for making out-of-band alert deliveries. Telephone numbers are provided to the communications manager by an alert destination list. Out-of-band alert deliveries nay be made via a modem, a universal asynchronous receiver transmitter, or the like.

Abstract: A computer system having an interconnection apparatus for connecting processors, peripherals and memories, the system including a plurality of electronic devices, and a multiple long bus structure with impedance elements disposed thereon for providing non-terminal termination points.

Abstract: A variable-input-voltage variable-switching-frequency power converter with a minimum frequency limit. The switching frequency never goes below a certain minimum while the converter is on. Thus switching frequency is dependent on input voltage, for input voltages in one range, and is NOT dependent on input voltage, for input voltages in another range.