[Coco] CocoFlash Updates

RETRO Innovations go4retro at go4retro.com
Mon Sep 12 13:25:37 EDT 2016


With apologies to Zippster, but in July or so, Barry asked if I could 
squeeze the Orchestra 90 functionality into the CocoFlash, so folks 
could assume some additional sound options for games and such.

This Summer was hectic, but I was able to do so, and the conversation in 
the list around the circuitry was very enlightening.  The Orch90 
functionality analog section is the top right of the cart, the R2R 
ladders are most prominent.  I used discrete resistors since I helped 
with layout and I could get the wattage rating I wanted more easily and 
more cheaply.

In any event, the (hopefully) finished cart design is shown above.  (The 
wire is due to a trace issue caused by some debugging efforts).  I have 
verified the sound waveform matches the OR90 output, but has a but more 
Vp-p, since I opted for some newer ABT-family latches, which drive to 
the rails a bit better.

When I get some time, I'll put some more information on the design on 
the web page, but feel free to ask questions if desired.


RETRO Innovations, Contemporary Gear for Classic Systems

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