Method and apparatus for DMA window display
US4777485A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 5, 1988 |
| Grant date | Oct 11, 1988 |
| Priority date | — |
| Expiry date | Apr 5, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G5/393
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention discloses apparatus and methods for direct memory access (DMA) having particular application for use in displaying digital images in an animated form on a CRT display. The present invention includes a DMA controller coupled over a bus to a frame buffer. The frame buffer includes one or more bit maps representative of the display. A block of memory within the frame buffer is mapped onto corresponding picture elements (pixels) on the display. The frame buffer continuously scans the bit map representing the CRT screen such that modifications to data bits within the frame buffer are correspondingly displayed on the screen. A plurality of windows may be displayed on the CRT having varying predefined widths which are appropriately represented within the frame buffer. Digital images stored as sequential "frames" of data in a memory, such as for example a hard disk or RAM memory, may be directly transferred from the memory to the frame buffer for display without the need for central processing unit (CPU) interaction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.