Video series: Vic20 Recreation (including VIC chip) in TTL

[beamrider]

https://www.youtube.com/watch?v=epuP5fAuRj0&t=401s

an interesting watch.

[beamrider]

Finding this series fascinating.

He now has a monochrome Vic-20 up and running using only modern parts and no FPGAs, which I belive is a first. Looking forward to him getting colour working in the next video.

Hope someone makes a PCB design for this on PCB-way so I can build it.

https://www.youtube.com/watch?v=giVttGIXC1E

[Orangeman96]

Finding this series fascinating.

He now has a monochrome Vic-20 up and running using only modern parts and no FPGAs, which I belive is a first. Looking forward to him getting colour working in the next video.

Hope someone makes a PCB design for this on PCB-way so I can build it.

https://www.youtube.com/watch?v=giVttGIXC1E

Couldn't you be the one who makes a PCB design based upon this series -- even a monochrome PCB like, right now? -OGM

[Lechuck]

Finding this series fascinating.

He now has a monochrome Vic-20 up and running using only modern parts and no FPGAs, which I belive is a first. Looking forward to him getting colour working in the next video.

Hope someone makes a PCB design for this on PCB-way so I can build it.

https://www.youtube.com/watch?v=giVttGIXC1E

Wow, that's amazing. Thanks for sharing. I remember watching some of Ben Eater's videos and thinking they were impressive. But these, applied to the VIC-20, are even better. I must admit that I can barely understand a small part of what he does, but still, it's very interesting to watch. And I agree that it would be great to see this in DIY kit form to build one.

Cheers

[Wilson]

Like many (I assume) I've always given almost spiritual reverence to the MOS custom chips. Probably born from the scene's focus on uncovering all their secrets.
When I saw Al Charpentier speak at VCF East a couple years back, my world was a little rocked when he described the 6560 as "just a counter".

[Mike]

[...] the 6560 as "just a counter".

Perhaps Mr. Charpentier should take a thorough look at what his creation is capable of when some restrictions on the VIC-20 motherboard that were built in by accident are removed:

[...] Idir was never attacked, and technically never surrendered. Its computer network was taken over by effector weapons, and - freed of designed-in limitations - upgraded itself to sentience, to become a Culture Mind in all but name [...]

... which could quite as well serve as inspiration for the VFLI mod.

Regarding the OP, it's quite interesting what can pass as VIC-20-like substrate. I however doubt this attempt on re-creating the VIC-I chip gets those things right that can't be inferred from the data sheet alone. Neither does the form factor of this VIC-I replacement address the repair of defective VIC-20 units.

[Wilson]

Yes, this is a coarse approximation of the real chip. And I'm sure a finer approximation would result in an exponentially more challenging design. Getting from 0 to 99% accuracy is probably easier than moving from 99 to 100%.
But it's a fun idea!

[beamrider]

Regarding the OP, it's quite interesting what can pass as VIC-20-like substrate. I however doubt this attempt on re-creating the VIC-I chip gets those things right that can't be inferred from the data sheet alone. Neither does the form factor of this VIC-I replacement address the repair of defective VIC-20 units.

I don't think he's aiming for 100% compatibility otherwise he wouldn't be using a 65C02, however it's still an interesting project IMO and 100% compatibility still hasn't been achieved anyway.

I don't see why it can't be made into a Vic-20 compatible PCB i.e. replace the entire motherboard?

[JonBrawn]

And I'm sure a finer approximation would result in an exponentially more challenging design. Getting from 0 to 99% accuracy is probably easier than moving from 99 to 100%.

Yes, yes, it is. Not only are there the internal timing aspects ("Just when should flipping the reverse-video bit take effect? Next CPU clock cycle? Middle of the character? End of the line?"), However, there are electrical considerations, too. A CR mainboard tolerates noisy clocks and address signals much more than an older 2-prong board, so I'm now adding more resistors to prevent ringing on these signals. I might have to add them to the data bus lines as well, but I haven't noticed those ringing so much.

[beamrider]

seems to have colour up and running now, although still work to do