[Coco] Homebrew CoCo Games

Zippster zippster278 at gmail.com
Sun Dec 13 12:34:44 EST 2015

There is no additional overhead for the CoCo after the AY (or whatever)
has done it’s part and the signal is put on the SND IN line at the cart port.

It’s all analog from there.  The cart port sound in line is then mixed with
the DAC output at the DAC in the case of the CoCo 2/3, or at the
MC14529B (between the DAC and the modulator) in the case of the 

Nothing would really be gained by a separate jack on the cart except
another output jack, one that would be missing whatever the DAC would
have contributed to the signal.

This is my understanding from the schematics, data sheets, etc.

- Ed

> On Dec 13, 2015, at 9:03 AM, farna at amc-mag.com wrote:
> From Nick Marentes:
> The audio from the sound chip is routed back into the CoCo via the SND
> IN pin of the cartidge edge connector and mixed in with the CoCo
> generated sound  to be played together via the monitor (mixed with
> composite video or the RGB audio out).
> A seperate audio jack is only necessary if the audio we want to hear is
> stereo and that depends if the sound chip chosen has a stereo output. A
> chip like the GI AY is only mono.
> =======================
> I was thinking that with a sound output jack it might be easier to get the
> sound out as the CoCo would have to do nothing but queue the sound chip.
> The sound chip could almost be run independently of the Coco. Well, some
> sound chips. Just feed data and let it go. I guess I'm getting way ahead
> of the original idea.
> -- 
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