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Re: IIgs Analog Video Circuitry
- Subject: Re: IIgs Analog Video Circuitry
- From: Daniel Kruszyna <dan@krue.net>
- Date: Wed, 28 Sep 2011 15:31:06 +0000 (UTC)
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MdntTrain <js@cimmeri.com> wrote:
> I don't have my schematic handy, but two types of chips (post the VGC)
> contribute to the rear port signals: there is the RGB-> NTSC converter
> chip around there (I believe it's the MC1377 or similar), and then
> there's the video D->A converters (DACs). I'm not sure whether the
> DACs are off shelf.
Each 4 bit component of the VGC output is first connected to a smaller SIP,
which I believe is an R/2R ladder DAC. From memory, the DACs are marked H2, H3,
and H4. It's the analog outputs of these three DACs which are then input to the
module in my original question. Apologies for not providing this detail
earlier.
-- Daniel