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Re: Crosspost: Did the cpu influence the display?

Subject: Re: Crosspost: Did the cpu influence the display?
From: "Homer J Simpson" <nobody@nowhere.com>
Date: Sat, 31 Dec 2005 02:38:52 GMT
Newsgroups: comp.sys.sinclair, comp.sys.tandy, comp.sys.atari.8bit, comp.sys.apple2, comp.sys.cbm
References: <1135598972.038067.292460@g47g2000cwa.googlegroups.com> <1135601178.453498.50970@f14g2000cwb.googlegroups.com> <4DDF9231A0%news@youmustbejoking.demon.cu.invalid> <GrWdnfXaiY45NCjenZ2dnUVZ_tydnZ2d@comcast.com>
Xref: g2news1.google.com comp.sys.sinclair:3823 comp.sys.tandy:870 comp.sys.atari.8bit:1610 comp.sys.apple2:2801 comp.sys.cbm:6826

"Michael J. Mahon" <mjmahon@aol.com> wrote in message 
GrWdnfXaiY45NCjenZ2dnUVZ_tydnZ2d@comcast.com">news:GrWdnfXaiY45NCjenZ2dnUVZ_tydnZ2d@comcast.com...

> 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.

Woz was the man!

References:
- Crosspost: Did the cpu influence the display?
  - From: "Bill H" <bill@ts1000.us>
- Re: Crosspost: Did the cpu influence the display?
  - From: "Andrew Owen" <aoweninoz@yahoo.com.au>
- Re: Crosspost: Did the cpu influence the display?
  - From: Darren Salt <news@youmustbejoking.demon.cu.invalid>
- Re: Crosspost: Did the cpu influence the display?
  - From: "Michael J. Mahon" <mjmahon@aol.com>

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