[Coco] Homebrew CoCo Games

Nick Marentes nickma at optusnet.com.au
Sun Dec 13 14:47:20 EST 2015

On 14/12/2015 3:34 AM, Zippster wrote:
> 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
> CoCo1.
> 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

That's right Ed. You can mix the sounds and essentially have 2 sound 
systems playing.

And it lowers cost by avoiding extra jacks and holes drilled on the 
cartridge casing.

It's about keeping it simple, elegant and low cost.


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