Abstract: A method and apparatus for automatically synchronizing the polarity of video signals generated by a graphics controller card to a display monitor is described. The present invention includes hardware circuitry comprising a storage unit, a detection unit, a selection unit that store, detect, and select input video signals, particularly a vertical and a horizontal synchronization signals, with the same or different polarity that are received from the graphics controller to a display monitor. The present invention synchronizes the polarity of input vertical and horizontal synchronization signals from the graphics controller prior to transmitting the sync signals to the display monitor. The detect and selection circuits of the present invention enable polarity of input sync signals to be synchronized without the use of software as practiced in the prior art.

Abstract: A graphics controller circuit for converting a plurality of monochrome pixel data into a corresponding set of color pixel data in RGB 888 format. The graphics controller circuit packs the converted color pixel data into a plurality of 64-bit color pixel words, with each color pixel word comprising two complete color pixel words and portion of at least one another color pixel word. By having color pixel data cross word boundaries, graphics controller of the present invention optimally stores color pixel data in color pixel words. The graphics controller circuit further includes a half-word addressable split-RAM which enables continuous availability of subsets of monochrome pixel data during each clock cycle for conversion to color data.

Abstract: A video controller for controlling at least two video displays having independent refresh rates and pixel resolutions. In a first embodiment, two separate data paths are provided within a video controller for each video display (e.g., CRT and LCD). Taking advantage of the increased bandwidth of 64 bit wide DRAMS, data for each data path may be retrieved in separate read cycles. Each datapath may operate at its own clock frequency characteristic of refresh rate and pixel resolution. The dual data path embodiment also reduces the complexity of the software model needed to drive such dual displays. IN an alternative embodiment, a single data path may be provided within a video controller to drive data for two video displays having independent refresh rates and pixel resolutions. A data "tag" (extra bit) is attached to each word or dword passing through the data path indicating the destination (e.g., CRT or LCD) of the video data. At the output of the data path, separate FIFOs (e.g.

Abstract: A multimedia system includes an audio/video decompresser/decoder for decompressing/decoding a compressed/encoded audio/video data stream in order to generate video images for display on a display device and to generate audio signals for audible reproduction. The multimedia system includes an integrated system and video decoder that has a novel memory controller and a novel method for displaying complete decoded/decompressed video frames on a display device without tearing. By use of selective storage of decoded/decompressed video frames in memory, tearing is prevented but information for predicting motion of a video segment is preserved.

Abstract: A decoder is disclosed for decoding MPEG video bitstreams encoded in any color space encoding format and outputting the decoded video bitstream to different sized windows. Both MPEG decompression and color space decoding and conversion are performed on the bitstreams within the same decoder. The disclosed decoder may be programmed to output the decoded video bitstream in any of three primary color space formats comprising YUV 4:2:0, YUV 4:2:2, and YUV 4:4:4. The decoder may also output the decoded bitstream to different sized windows using Discrete Cosine Transform (DCT) based image resizing.

Abstract: A file access history attribute may be encoded and stored with a file in a computer memory. The file access history attribute may provide information as to the date of most recent access and the level of access on which date. In addition, the file access history attribute may provide information concerning recent file history (e.g., previous nine days), quarterly history (e.g., 80 days preceding the previous nine days), as well as long-term history (e.g., beyond the 80 day period). The encoding technique of the present invention may compress file access history information into a compact file access history attribute (e.g., six to twelve bytes). Disk caching software, for maintaining files in a hard drive of a local computer coupled to a network, may utilize the file access history attribute in deciding which files are to be stored in the local hard drive and which should be migrated to network storage or archive.

Abstract: A high performance Local Bus Peripheral Interface (LBPI) for a computer local bus and high performance peripheral interface(s) uses a pipelined architecture to increase use of available data transfer bandwidth. The LBPI coupled between the computer local bus and peripheral interface(s) is provided a pipelined architecture including a Read Ahead Buffer, a Read Ahead Counter, a Data Out Latch, and a controlling State Machine with a Configuration Register. The LBPI supports DMA and PIO data transfers on the peripheral side. In another embodiment, the LBPI translates memory data transfers into IO data transfers to improve efficiency of IO data transfers. A DMA Timeout Counter is used during DMA mode data transfer operations to prevent the system from indefinitely waiting for an appropriate DMA Request Signal from a selected peripheral. During a DMA mode data transfer operation, forced interrupts may be generated and transmitted to the host in order to emulate a PIO mode data transfer operation.

Abstract: An integrated circuit allows a user or system designer to program the length of a transaction cycle by programming the lengths of the setup time period, the command time period and the recovery time period, individually. An eight-bit register is used to store a two-bit prescaler value and a six-bit count value for each of the setup, command and recovery time periods. The value represented by the prescaler is then multiplied by the count value and the resulting value is input to a timer which counts down from the resulting value, signalling to a state machine when it has reached zero. A four-state state machine sends the command to begin each transaction cycle and each setup, command and recovery time period within each transaction cycle. The state machine is notified by the timer when the time period has elapsed for each of the three states so that it can send the signal to begin the next state.

Abstract: A periodic training signal is transmitted over a communications channel from a transmitter to a receiver. At the receiver, a spectrum estimation module is used to measure the spectrum of a set of uncorrected samples of the periodic training signal. The spectrum estimate is available at a discrete frequency spacing of an integer fraction (L>1) of the frequency spacing of the set of samples of the periodic training signal. A timing offset estimation module is then used to measure the ppm offset between the local and remote crystals. The timing offset estimation module runs in parallel with the spectrum estimation module. The spectrum estimate is convolved with the DFT of a periodic ramp function and the result squared to product an error spectrum. The error spectrum represents the error induced by differences between timing in the transmitter and receiver clock. The error spectrum is subtracted from the estimated spectrum to produce a corrected spectrum.

Abstract: An apparatus for controlling a flat panel display with reduced flicker, particularly during grey scale shading. Three shading pattern lookup tables are provided, one for each sub-pixel color (Red, Blue, Green). Each shading pattern lookup table outputs a plurality of shading pattern duty cycle signals, each representing a different shade level. The phase of the three duty cycle signal patterns may be altered by adding a predetermined offset amount to one or more of the shading pattern lookup table addresses. By altering the phases of the outputs of the shading lookup tables, peak current demand within the flat panel display may be reduced and flicker or strobing of individual pixels may be reduced or eliminated.

Abstract: A multimedia system including an audio/video decoder/decompresser for decoding/decompressing a compressed encoded audio/video data stream to generate video images for display and audio signals for audible reproduction. The multimedia system includes an integrated system and video decoder with an audio/video synchronization circuit for substantially synchronizing the display of video images with audio playback. In addition, a step control is provided to allow for viewing of video images on a frame-by frame basis or to freeze or play video in slow motion. When step control is activated, audio output is muted. Audio data corresponding to displayed video is transmitted to the muted audio decoder. An internal system clock may be suppressed to the system clock counter. An external CPU may provide system clock start times corresponding to video frames to be displayed. The external CPU may increment the system clock counter by a an amount corresponding to the difference between a successive frame or number of frames.

Abstract: A display controller for a computer or the like stored display data in a tiled format in a display memory. Tile shape may be dynamically altered depending upon display mode (resolution, pixel depth, or the like) or other display factors. Tile shape (height versus width) may be optimized for different types of display (e.g., video, text, graphics, or the like). A display memory address conversion apparatus may receive pixel position data (e.g., from a BIT BLT engine or the like) and tile shape data and convert pixel position data to a tiled display memory address.

Abstract: An apparatus for providing register compatibility between integrated circuits having different register and interrupt configurations is designed to operate with software that was written for previous hardware. Versions of software written for previous hardware attempt non-native register accesses for which the integrated circuit is designed to emulate the non-native register set. Versions of software specifically written for the present hardware attempt native register accesses for which no emulation is necessary. In the preferred embodiment only one physical register set is included on the integrated circuit and a compatibility engine is used when a non-native register access is attempted. The compatibility engine is coupled between a bus interface unit and the physical register set and allows a user or system designer to address a register set of another integrated circuit having a different configuration than the physical register set.

Abstract: A display controller to upscale a source video image for display on a display unit of a computer system. An encoder circuit in the display controller circuit stores in a local memory pixel data of previous scan lines required for interpolation in a compressed format using differential pulse code modulation (DPCM) scheme. Encoder circuit avoids a slope overload condition by generating compressed data for a first pixel of each scan line by using the first pixel itself as a reference. Encoder circuit generates compressed data for other pixels by using at least one prior pixel in the corresponding scan line. A decoder circuit decompresses the pixel data into original format prior to sending to an interpolator. The interpolator receives a present scan line and the decompressed data of previous scan lines, and interpolates the received pixels to generate additional pixels required for upscaling the source video image.

Abstract: A method and apparatus for monitoring and controlling power to a device such as a PCMCIA/PC card. A PCMCIA/PC card adapter is provided for communicating data and control signals to and from a PCMCIA/PC card and a host processor. The PCMCIA/PC card adapter may communicate with the PCMCIA/PC card to determine the correct voltage(s) for the PCMCIA/PC card. The PCMCIA/PC card may then communicate instruct a power control circuit to provide an appropriate voltage to the PCMCIA/PC card. The power control circuit may be provided with status monitoring registers containing status data reflecting monitored conditions of the PCMCIA/PC card and power supply. A System Management Bus (SMB) may link the power control circuit and the PCMCIA/PC card adapter. If an abnormal status is detected in the PCMCIA/PC card or power supply (e.g.

Abstract: A VGA compatible graphics controller receives character data, attribute data and font data, each of which are stored in different planes of a display memory. The font data comprises bit maps of at least two character fonts, which may be user fonts or default fonts loaded from a controller BIOS. The video controller detects attempts by a host CPU to write data into plane two of display memory (where character font bit maps reside). The address generated by the host CPU is scrambled to produce a video font cache address. The character font bit maps are stored in a video font cache at the scrambled address. The font select bits of the CPU generated address are used as a byte select to store a particular font at a byte location at a selected video font cache address. In the preferred embodiment, eight fonts may be stored in the video font cache, one scan line each font of each character as a different byte at each address of the video font cache in a 64 bit wide DRAM.

Abstract: A method and apparatus to stretch video images in a graphics controller chip of a computer system. The graphics controller chip fetches four pixel data comprising two pixel data each from a first scan line and a second scan line of a source video image, and generates a set of additional pixels in a rectangular area defined by the four pixels. The graphics controller chip stores the pixels of rectangular portions in a display memory, and displays the pixel data of the stretched video image in a scan line order.

Abstract: A peripheral interface system and apparatus including a pair of integrated circuits, referred to as a system adapter and a socket controller, use a communication protocol, referred to as a windowed-interchip-communication protocol, to interface peripherals, such as PCMCIA cards or infrared devices, and other subsystems having different formats with a CPU system bus. The system adapter communicates to a hard disk drive subsystem using the ATA communication standards to interface an ATA hard disk drive with the CPU system bus. Communication between the system adapter and the socket controller, which communicates with PCMCIA peripheral cards and IR peripherals, is accomplished using the windowed-interchip-communication protocol which may share hardware resources with other communication protocols. Communication between the system adapter and the hard disk drive and between the system adapter and the socket controller may be provided on the same chain of a standard 40 signal ribbon cable.

Abstract: A method and apparatus for integrating a row address strobe signal monitoring circuit in a graphics controller is described. The present invention includes an improved graphics controller comprising a bi-directional input/output pad and a row address strobe signal snooping circuit to monitor the row address strobe signal to detect the pre-charge status of the signal prior to a memory access by the graphics controller. The input/output pad of the present invention enables the graphics controller to simultaneously receive and drive a row address strobe signal upon being granted permission to access memory. The row address snooping method of the present invention enables the graphics controller to pre-charge the row address strobe signal while the controller is in an inactive memory access state.

Abstract: A selective low power clocking apparatus and method is used to reduce power consumption by an electronic system or integrated circuit that is coupled to an external system via a system bus which is configured to selectively transmit or receive signals from the electronic system or integrated circuit. The electronic system or integrated circuit includes a plurality of sub-circuits or functional blocks. Each sub-circuit or functional block is configured to operate under control of a clock signal and further includes an apparatus for holding or rejecting the clock signal. Once each sub-circuit within the electronic system or integrated circuit rejects the clock signal, the clock signal to that sub-circuit is disabled. The arbiter circuit continuously monitors the system bus. Upon detecting that the external system needs to transmit or receive signals from the electronic system or integrated circuit, the arbiter re-enables the clock signal to the sub-circuits which are required for the transmission or reception.