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
Single-pass Barankin Estimation of scatterer height from SAR data
Flash multi-level threshold distribution scheme
Error recovery storage along a memory string
Portable hand-held multi-function device for storing, managing and combining rewards
Memory device and semiconductor device
Maize variety X00C175
Low latency interrupt collector
  Randomly Featured Patents
Sinker unit of weft knitting machine
Light-emitting element and display device using same
Water glass-based inorganic material and process for producing the same
Storage rack shelving
Joint lock with improved structure
Method for treating nicotine addiction
Method and system for a client invoking on an interface defined in a first notation to invoke an object having an interface defined in a second notation
Clock generator and USB module
Dual rotor electromagnetic machine
Nest tire structure for a run-flat tire