XPost: comp.sys.sinclair, comp.sys.atari.8bit, comp.sys.apple2   
   XPost: comp.sys.cbm   
   From: mjmahon@aol.com   
      
   Darren Salt wrote:   
      
   > True. But the *layout* of the display memory was certainly influenced by the   
   > CPU.   
      
   In the case of the Apple II, the (somewhat unusual) layout of display   
   memory was a consequence of using the video refresh to accomplish the   
   refresh of the DRAMs.   
      
   The result is that no special refresh circuitry is used, and, since   
   all video accesses occur on the alternate half-cycles not used by   
   the processor, there is never any interference with the processor   
   for video or DRAM refresh.   
      
   A little cleverness simplifies a lot.   
      
   -michael   
      
   Music synthesis for 8-bit Apple II's!   
   Home page:  http://members.aol.com/MJMahon/   
      
   "The wastebasket is our most important design   
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   --- SoupGate-Win32 v1.05   
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