Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Video memory system










Image Number 6 for United States Patent #4644495.

An improved video memory system includes a program memory, a display data memory, and a plurality of data fetchers. The data fetchers are used to indirectly address the display data in the display data memory. The data fetchers are programmed during vertical blanking so that selected display data is fetched at selected vertical display positions. During each scan line each data fetcher is "read" by: (1) decrementing a counter in the data fetcher; (2) comparing the counter value against preselected top and bottom values; and (3) using the counter value to indirectly address display data that is to be displayed on the current scan line if the counter value is between the top and bottom values. This relieves the host computer of having to keep track of the current vertical display position, thereby freeing it to use the saved computer cycles to produce more interesting viedo games with more complex display graphics. In addition there are provided data fetchers that can be programmed to periodically issue signals usable either for drawing a line with a predefined slope or modulating the amplitude of a sound generator.








 
 
  Recently Added Patents
Ice tray for refrigerator
Rose plant named `Esm R068`
Vehicle hood
Reading apparatus and reading method
Security authentication method, apparatus, and system
Method and system for reduction of quantization-induced block-discontinuities and general purpose audio codec
Manufacturing process for cellular screening substratum, resultant substratum, and method and apparatus for screening
  Randomly Featured Patents
Recycled suppressor regenerants
Connecting device for ignition systems of internal combustion engines
Planar structure for non-volatile memory devices
Amphoteric polyelectrolite, method for production thereof, and organic sludge dehydrater
Barrier coating process using olefin resin and urethane resin
Magnetic tape cartridge for housing a reel
Device for measuring rotation having magnetic relative positioning of encoder and sensor
Valve construction and method of use
Drive compensation circuit for synchronous rectifier and method of operating the same
Infrared radiation sensor