Title:
VIDEO GRAPHICS CONTROLLER HAVING LOCKED AND UNLOCKED MODES OF OPERATION
Document Type and Number:
WIPO Patent Application WO1999026145
Kind Code:
A3
Abstract:
A video graphics controller (VGC) for communicating with a frame buffer memory and a display device includes a first-in, first-out (FIFO)-configured memory, a memory controller for communicating with the frame buffer memory and controlling the FIFO-configured memory, and read and write pointers for the FIFO-configured memory. A subtractor is coupled to the read and write pointers for generating a difference signal which is coupled to the memory controller, and the read pointer generates a read carrier signal which is provided to a lock detector along with an end-of-frame signal. The lock detector generates an output signal which is coupled to the memory controller in order to place the video graphics controller in a locked mode of operation if no read carry signal is generated during an inputting of an entire frame of information into the FIFO-configured memory, and in an unlocked mode of operation if a read carry signal is generated prior to the completion of the inputting of an entire frame of information.
Inventors:
WALSH CHRISTOPHER
Application Number:
PCT/IB1998/001605
Publication Date:
July 29, 1999
Filing Date:
October 12, 1998
Export Citation:
Assignee:
KONINKL PHILIPS ELECTRONICS NV (NL)
PHILIPS SVENSKA AB (SE)
PHILIPS SVENSKA AB (SE)
International Classes:
G06F5/10; G09G5/00; G09G5/395; H04N5/907; (IPC1-7): G09G5/08; G06F13/00; G09G5/00
Foreign References:
| US5682554A | 1997-10-28 | |||
| US5471583A | 1995-11-28 |
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