Dual displays having independent resolutions and refresh rates
US5841418A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2360/04
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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 allow…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.