| 摘要 |
A digital display circuit for use with a video game or other displays fabricated as an MOS integrated circuit is described. The circuit permits the simultaneous display of many different patterns (and the simultaneous display of the same pattern) at any locations on a raster scanned cathode ray tube. Content-addressable memories are employed to compare the contents of a digital beam location counter with desired object locations. A random-access memory is then used to address a pattern library where each line of the patterns is stored. When more than one pattern is displayed at the same location, counting in the digital beam location counter is delayed to permit accessing of more than a single pattern line from the pattern library. A displacement counter is employed to store a count representative of the displacement between the actual beam position and the contents of the beam counter. The beam location counter is incremented at a faster rate during non-display periods to compensate for delayed counting. The circuit provides an easy method for detecting the coincidence of patterns and the coincidence of patterns with a grid.
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