Resources Contact Us Home
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
Apparatus and method for scrolling a screen of a portable terminal having a touch screen
Intake parameter-calculating device for internal combustion engine and method of calculating intake parameter
System and method for leveraging independent innovation in entertainment content and graphics hardware
Method and apparatus for transcoding and transrating in distributed video systems
Radio communication system, base station device and mobile station device utilizing an intermittent reception
Query optimization with awareness of limited resource usage
Vanadium, cobalt and strontium additives for use in aluminum back solar cell contacts
  Randomly Featured Patents
Database table look-up
Generation triple-targeting, chiral, broad-spectrum antimicrobial 7-substituted piperidino-quinolone carboxylic acid derivatives, their preparation, compositions and use as medicaments
Gas oven
Epitaxy profile engineering for FinFETs
Compression relief retarders for supercharged internal combustion engines
Method and device for capacitive detection of objects
Package for an active medical device
Modified thermo-resistant DNA polymerases
Composition for improved adhesion of vinylidene chloride latex to ionomer films
Inkjet printable electrode composition, electrode including the same, and secondary battery including the electrode