Computer graphics processing and selective visual display system – Plural display systems – Diverse systems
Patent
1995-06-07
1998-11-24
Hjerpe, Richard A.
Computer graphics processing and selective visual display system
Plural display systems
Diverse systems
345 1, 345115, G09G 500
Patent
active
058414185
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.
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Bindlish Rakesh
Bril Vald
Eglit Alexander Julian
Fuiks Ken
Han Robin Sungsoo
Bell Robert P.
Cirrus Logic Inc.
Hjerpe Richard A.
Lang Kent C.
Shaw Steven A.
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