Here now, finally, are the schematics for the C74-6502.
Truth be told, I had wanted to wait until these were made final before posting. But given the various requests I've received, I decided to relent and put these up in this "not quite finished" state. The attached schematics do accurately reflect the existing prototype, and are annotated to clearly indicate with the various patches that were applied during debugging. I have attached also an accompanying
PCB Patch Guide detailing all such patches as an aid to anyone wishing to build a working unit from the prototype boards (we already have
one such project underway!).
Although work remains before we can officially call an end to this project, I did want to take a moment and say thanks on behalf of Team C74. What an incredible adventure this has been! I am very grateful to all here who supported these efforts with such enthusiasm and interest. It's a wonderful privilege to be part of this community.
And of course, a special thanks also to the rest of Team C74 -- ttlworks and Dr Jefyll -- for their generous help and friendship.
... But there is no rest for the weary, as already work has started on a potential successor to the C74-6502. Can it be made faster still? Stay tuned ...
Notes to the schematics:
- The annotated schematics are large files -- regrettably that had to be the case to make them legible.
- I did not complete annotated schematics for Card C (K24 card). There are a couple of patches for this card outlined in the Patch Guide.
- The K24 SPI circuitry remains untested at this point. All other functions in the K24 Card work as advertised.
- I will in time post Gerbers, BOMs and Eagle files on the project website. In the meantime, please PM me if you are interested.
First up, the PCB Patch Guide:
Attachment:
Block Diagram by ttlworks:
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C74-6502 Block Diagram.png [ 64.06 KiB | Viewed 16469 times ]
Card A Schematic -- Page 1
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Card A-Registers Sch P1 (V1.0 Patched).png [ 8.38 MiB | Viewed 16469 times ]
Card A Schematic -- Page 2
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Card A-Registers Sch P2 (v1.0 Patched).png [ 5.87 MiB | Viewed 16469 times ]
Card A Schematic -- Page 3
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Card A-Registers Sch P3 (V1.0 Patched).png [ 610.23 KiB | Viewed 16469 times ]
Card B Schematic -- Page 1
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Card B-ALU & CU Sch P1 (V1.0 Patched).png [ 7.78 MiB | Viewed 16469 times ]
Card B Schematic -- Page 2
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Card B-ALU & CU Sch P2 (V1.0 Patched).png [ 2.18 MiB | Viewed 16469 times ]
Card C Schematic -- Page 1 (Unannotated)
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Card C-K24 Sch p1.png [ 313.55 KiB | Viewed 16469 times ]
Card C Schematic -- Page 2 (Unannotated)
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Card C-K24 Sch p2.png [ 20.68 KiB | Viewed 16469 times ]