The MOS 6567/6569 video controller (VIC-II) and its application in the Commodore 64 |
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Contents 3. Description of the VIC |
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The VIC does five read accesses in every raster line for the refresh of the dynamic RAM. An 8 bit refresh counter (REF) is used to generate 256 DRAM row addresses. The counter is reset to $ff in raster line 0 and decremented by 1 after each refresh access. So the VIC will access addresses $3fff, $3ffe, $3ffd, $3ffc and $3ffb in line 0, addresses $3ffa, $3ff9, $3ff8, $3ff7 and $3ff6 in line 1 etc.
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