Cirrus Logic Inc.

Telecruz Technology, Inc.

Nvidia Corporation

Nvidia International, Inc.

Vlad Bril

Alexander Julian Eglit

Rakesh Kumar Bindlish

Sridhar Kotha

Robin Sungsoo Han

Sagar Waman Kenkare

Paul W Heller

Mahmud M Assar

Fred D Harris

Dwarka Partani

David Keene

Chester F Bassetti, Jr

Boyd Gayle Pett

Ken Fuiks

Keith H Uhlin

Prakash C Agarwal

Dennis Z Lin

Thomas Shieh-Luen Ho

Chin-Hsian Chang

Prakash Pai

Edmund Christian Strauss

Muralidhar Reddy Jammula

A display controller in a computer system controls the asynchronous output of graphics display data in a computer system having at least one fixed resolution flat panel display. Fixed panel displays may have problems displaying non-native resolutions particularly at lower resolutions. The controller of the present invention uses a time base converter, horizontal and vertical Discrete Time Oscillators (DTO), and polyphase interpolator, which may be Discrete Cosine Transform (DCT)-based to expand graphics display data asynchronously from native resolution to at least one resolution suitable for display on a fixed resolution panel. Graphics data may also be output asynchronously to a CRT. Time base converter receives frequency related input parameters and generates at least one asynchronous output at the desired output resolution.

Method and apparatus for asynchronous display of graphic images

A display controller in a computer system controls the asynchronous output of graphics display data in a computer system having at least one fixed resolution flat panel display. Fixed panel displays may have problems displaying non-native resolutions particularly at lower resolutions. The controller of the present invention uses a time base converter, horizontal and vertical Discrete Time Oscillators (DTO), and polyphase interpolator, which may be Discrete Cosine Transform(DCT)-based to expand graphics display data asynchronously from native resolution to at least one resolution suitable for display on a fixed resolution panel. Graphics data may also be output asynchronously to a CRT. Time base converter receives frequency related input parameters and generates at least one asynchronous output at the desired output resolution.

A flat panel display controller is provided with a circuit for monitoring clocking signal(s) to the flat panel display. A clocking signal output to the flat panel display may be fed back to the display controller using a conventional I/O pad. In the preferred embodiment, the fed back clocking signal resets a counter. In a second embodiment, the fed back clocking signal may then pass through an edge detector whose output then resets the counter. The counter will overflow if a edge signal is not received within a predetermined time period. If an overflow occurs, the carry signal of the counter will initiate a flat panel power shutdown through power control circuitry. The clock signal for the counter may be derived from an off-chip oscillator such that if a failure occurs within the display controller, the counter will continue to function.

Method and apparatus for providing LCD panel protection in an LCD display controller

A low pass digital filter using cascade polyphase recursive digital signal processing circuit. The filter in the receive direction may contain a re-sampling Hogenauer filter followed by an equalizer filter to correct for its non-flat pass-band spectral response. The output of the spectral equalizer may be processed by a poly-phase re-sampling filter to reduce the sample rate. A clean-up filter may insert two stop-band spectral intervals in the frequency response of the earlier stages. The filter in the receive direction may be implemented by using similar components in the reverse order.

Low pass digital filter implemented in a modem of a television system

A television system (TV) which enables a user to view display represented by a television signal as well as to access data network applications. The TV includes an on-screen-display (OSD) controller which stores the network application data and other display entities in a memory module as separate bit maps. A single image for display on a TV display screen is generated by overlaying all the display entities (including television signal, network application data, pointer, and low resolution data) according to a predetermined priority. Display entities (other than TV signal) are stored in separate portions of the memory module as independent surfaces to enable the displays of individual display entities to be generated and modified according to the individual display entity requirements.

Method and apparatus for enabling a user to access data network applications from a television system

A clock generation circuit for use in a television system displaying images encoded in television signals and images represented by network application data. The clock generation circuit generates a clock signal synchronized with HSYNC signals of the television signals. The clock generation circuit includes a phase-lock-loop (PLL) circuit and a tracking block. PLL circuit includes an oscillator (e.g., VCO) driven by an error signal to generate an internal periodic signal having frequency substantially equal to the frequency of the desired clock signal. The tracking block includes a resettable VCO (RVCO) driven by the error signal. A restart signal is asserted prior to the expected arrival time of the HSYNC edge to cause the RVCO to stop generating the desired clock signal. The restart signal is deasserted on receiving the HSYNC edge to cause the RVCO to start generating the clock signal. Accordingly, the clock signal is synchronized with the HSYNC signal.

Circuit and method for generating a clock signal synchronized with time reference signals associated with television signals

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., LCD and CRT) are provided to temporarily store video data. FIFO pointers are fed back to a sequence controller to drive data read cycles from display memory. The use of tags and FIFO pointer feedback allows two video displays to be driven at different data rates, allowing for independent resolution and refresh rates in each display.

Dual displays having independent resolutions and refresh rates

A memory controller for controlling accesses to a memory storing display entities including network application data displayed on a display screen of a television system. For performing a display screen refresh operation, the network application data is retrieved with a predetermined period. Accordingly, the memory controller determines an expected time for receiving the next request for retrieving the network application data for screen refresh. The memory controller blocks any lower priority memory access requests from a few clock cycles prior to the determined expected time. As a result, the requests for retrieving network application data can be serviced in an acceptable time.

Method and apparatus for refreshing a display screen of a television

An integrated circuit such as a video controller may be provided with core logic circuitry using CMOS technology which may be operated at different supply voltages such as 3.3 or 5 Volts. At lower supply voltages, the CMOS circuitry may run slower. For a video controller, certain higher resolution, pixel depths, and refresh rates may require high speed operation of the video controller. A monitoring circuit monitors the video mode, pixel resolution, pixel depth, and refresh rate and determines which supply voltage may be used to operate the video controller at such levels. An output signal from the monitoring circuit may be used by a switching circuit to supply an appropriate supply voltage to the integrated circuit. At lower performance levels, the integrated circuit may be operated at lower voltages to conserve power.

Programmable core-voltage solution for a video controller

A television system (TV) with an interlaced display screen for displaying network application data. A flicker filter is preferably implemented as an infinite impulse response (IIR) filter to eliminate sharp transitions in the network application data images. A random access memory is used to store the lines of the filtered images and any adjacent lines used for the filtering operation. Alternate lines of the filtered images are retrieved from the random access memory to provide an interlaced image of the filtered network application data images. The interlaced images are displayed on an interlaced display unit of a television system.

Flicker filter and interlacer implemented in a television system

A display controller in a computer system controls the output of graphics display data in a computer system having a fixed resolution flat panel display. Fixed panel displays may have problems displaying non-native resolutions particularly at lower resolutions. The controller of the present invention uses a Discrete Time Oscillator (DTO) based clock divider and DCT based polyphase interpolation to upscale graphics display data from a first resolution to the panel resolution. DTO clock divider circuit synchronizes scan clocks between the input resolution and the desired output resolution. Within graphics display area, MVA.TM. display at greater color depth and resolution may be accommodated by additional DTO divider and interpolation steps.

Method and apparatus for expanding graphics images for LCD panels

Method and apparatus for enabling a user to access data network

Motion video may be imported into a personal or portable computer through an I/O port having a limited data bandwidth, such as a PCMCIA interface. Motion video data is compressed by sub-sampling both luminance and chrominance difference data for different sized groups of pixels. The compression apparatus may be formed on a PCMCIA card which interfaces with a personal or portable computer. Motion video data, compressed by as much as 5:1 or 6:1, is transferred through the PCMCIA card to a host computer. The host computer may serialize the compressed data and store the data in serialized compressed format in a video memory of a video controller. The video controller is provided with decompression circuitry to decompress the motion video data into luminance and chrominance difference data. The luminance and chrominance difference data is converted into RGB data and displayed in a video display.

PCMCIA video card

A television system (TV) with an interlaced display screen for displaying network application data. Pixel data elements representing network application data display are received in a non-interlaced mode. The received data is filtered to reduce sharp transitions in the display. The filtered data is provided in an interlaced format (i.e., only alternate lines of a frame) for display on the television display screen. The interlaced image display is combined with the television signal display by selecting one of them on point by point basis. Flicker is reduced substantially in the final display of network application data due to the filtering.

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Campbell, CA, United States of America

Vlad Bril