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W65C265S Primary + AV Boards

Updated: Apr 20

Continuing my W65C265S project series, I am at a nice milestone where I have a second version of a PCB (actually, a pair of PCBs) -- with significantly expanded functionality from my first PCB. For more background on my work on this up to this point, check out rehsdonline.com/post/w65c265s-single-board-computer. My goal in this post is to work through the two PCBs in the rendering below.


This post will be updated as I work through the design and build.



[February 07, 2026] I have received in the 'Primary' PCB, the lower of the two boards in the image above.






Tone Generators



Maybe a lightweight operating system?







VGA

For my VGA on the AV board, see the VGA page in the AV schematic (below in this post). To support this VGA circuit design, I have three GAL22V10D ICs (PLCC package). I have posted the logic for the GALs under Schematics below, too. As of this point in my build, the snapshot of code and schematics (both Primary and AV boards) are available here.




Audio



Parallel Interface Bus (PIB)





SPI Real-time Clock




SD Card



PS/2 Mouse


SNES Gamepad Controller


Music, Sound Effects, and Video Come Together

Related, older video on PSGs




More to come!



Schematics




Decode logic for AV board, including VGA:



Updated decode logic to support add-on card with two additional VIAs:









Source Code


 
 
 

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