The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 12, 2000
Filed:
Aug. 19, 1998
Vlad Bril, Campbell, CA (US);
Rakesh Bindlish, San Jose, CA (US);
Ken Fuiks, Fremont, CA (US);
Robin Sungsoo Han, Saratoga, CA (US);
Sridhar Kotha, Fremont, CA (US);
Alexander Julian Eglit, San Carlos, CA (US);
Cirrus Logic, Inc., Fremont, CA (US);
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., 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.