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Re: C64/128 vs Apple -- Video?
- Subject: Re: C64/128 vs Apple -- Video?
- From: Linards Ticmanis <ticmanis@gmx.de>
- Date: Mon, 26 Jun 2006 23:28:27 +0200
- In-reply-to: <75xng.123172$dW3.43899@newssvr21.news.prodigy.com>
- Newsgroups: comp.sys.apple2
- Organization: Arcor
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Bryan Parkoff wrote:
> Now, what about C64/128? It has 40x25 lines so it looks like 640x200
> resolution. Do C64/C128 use CGA font? Is video circuit more complex, but
> Apple II's video circuit is little simpler? I am curious.
Commodore doesn't use artifact color. Their circuit creates the chroma
signal independently of the luma. So they are not bound to a n�3.58 MHz
pixel clock. In Commodores, there are 7 (NTSC) or 9 (PAL) chroma cycles
per 8 luma cycles.
Also this makes it easy to use almost the same circuit and still be
fairly compatible in software for NTSC and PAL.
The Euroapple uses a very indirect method of PAL color creation: It
reads and interprets the NTSC output signal of the normal circuits, then
duplicates it in PAL. The European Commodores create PAL directly.
--
Linards Ticmanis