New retro Vic-20 clone

[danwerner]

Finally, the VIC-2020 is working well and is far enough along where I can publish all of the project materials. The board works great and has passed all of my initial tests. I really like the Cherry MX keyboard and the custom printed keycaps.

All of the KiCad files, Gerber files and the Keycap art is located at:

https://bitbucket.org/danwerner21/vic2020


There are some project docs that describe the differences from the original VIC-20 and give some general information on how to build the system. ONE NOTE THOUGH -- the 3d printed case is still a work in progress (and will be for a few more days) do not print the STL files that are in the project as the boards will not quite fit in them yet. Will post again once the case is complete and ready to print.

Enjoy - and please feel free to reach out with any questions.
Dan Werner

(I apologize for the flipped images, this appears to be an artifact of the image editing software I use, and no matter what orientation I save them in, the always appear flipped)

[Mike]

Hi, Dan,

first of all, welcome to Denial!

I already stumbled across your project today when I was lurking in the 6502.org forums.

That is a nice reproduction and re-imagination of the VIC-20 mainboard we are seeing here. It is interesting that you also aimed to remove some restrictions that had been built into the original mainboard by accident.

Quoting from your repository:

[...] the 6522 IO port that was dedicated to the user port on the VIC-20 has been repurposed as a "Page Register" (located at 0x9110 or 37136) on the VIC-2020 allowing 128 pages of color ram to be available for the VIC chip. This should give the ability for some very interesting color effects to be produced on the VIC-2020, while still keeping the VIC mostly compatible.

[...] the VIC-2020 in even its lowest memory configuration has the VIC 3K memory expansion enabled at RAM1, RAM2, and RAM3, giving it's base ram to be 6k.

Well, those are actually 8 KB RAM from $0000 to $1FFF, of which the OS takes 1K for zeropage, stack and OS workspace. Another 0.5K are reserved for the text screen and so you are left with 6.5K for BASIC programs.

That configuration (including the re-use of VIA #1 port B as colour RAM banking register) indeed allows for very colourful bitmap graphics over a large display size (i.e., overscan). You should check out my VFLI mod.

Unfortunately, the name of your project, "VIC-2020 FICHTER EDITION", clashes with another project of mine, VIC-2020 MINIMON. It is a utility cartridge still under development, but there already exist functioning prototypes.

Greetings,

Michael

[danwerner]

Thanks for the Reply!

Well, those are actually 8 KB RAM from $0000 to $1FFF, of which the OS takes 1K for zeropage, stack and OS workspace. Another 0.5K are reserved for the text screen and so you are left with 6.5K for BASIC programs.

You are, of course, correct -- too hasty of typing and too little thinking I guess! I have corrected the repo to reflect the correct information.

. . . . You should check out my VFLI mod.

Nice -- I guess there should be some nice effects possible indeed . . . since it looks like you have already shown that this can create some very nice images!

Unfortunately, the name of your project, "VIC-2020 FICHTER EDITION", clashes with another project of mine, VIC-2020 MINIMON. It is a utility cartridge still under development, but there already exist functioning prototypes.

Again, looks like you are correct -- If you think the name conflict will create confusion, it would be simple enough for me to change to VIC-2021 If you feel strongly about it, let me know and I will revise my documentation.

Dan

[Mike]

If you think the name conflict will create confusion, it would be simple enough for me to change to VIC-2021 If you feel strongly about it, let me know and I will revise my documentation.

There is a precedent. At those times the cartridge "VIC-1001 Waterloo BASIC" used the same numerical designator (or part number) as the Japanese initial release VIC-1001, by mistake.

Now, if we agree upon that the four digit part numbers are the default case for peripherals, furthermore that I announced my project quite early in 2019 then both points give priority to the cartridge. I have no hard feelings about this though.

Here is a suggestion: as you have already included quite some improvements to the original PCB, how about you incorporate the MINIMON cartridge as well? After all one of its main functions is to de-multiplex the I/Ox select signals between a 2 KB memory chip ((E)EPROM or RAM) and a slave cartridge. In that sense it acts more like an extension of the mainboard, not so much as a dedicated cartridge.

If you are interested, we can discuss this in more detail in PM.

Michael

[Vic20-Ian]

Fantastic project. Well done on your achievement.

I don't see any clash or confusion in calling your Machine the Vic 2020 - it was released in 2020 and is hardware not a cartridge that could be confused with 2020 Minimon.

There is room for both.

[Jeff-20]

[crusti]

8bit guy had a Youtube episode


Are they available for purchase yet?
I've bought 4 VICs now and each one has some issue and Im not techy enough to find the faults.
This could be very cost effective way instead of my hunt for the perfect VIC.

It looks very nice.

[prowlr]

I just finished watching the 8-bit guy video myself. I was also curious on if/when/where/who much one of these would be.

[Falkon215]

Has anyone watched the 8-bit guy assemble a vic-2020 kit.Can't find any information or a websight for this kit build.

[Mike]

...

...

The OP contains a link to all KiCad files, Gerber files and Keycap art: https://bitbucket.org/danwerner21/vic2020.

I'd presume The 8-Bit Guy used that info to order all those parts by himself.

[beamrider]

Looks good, he's chopped a few too many corners for me personally though i.e. a cassette connector and an external switch block for memory configuration.

[Vic20-Ian]

Looks good, he's chopped a few too many corners for me personally though i.e. a cassette connector and an external switch block for memory configuration.

It is not beyond the skills of any hobbyist assembling this kit to move the switches off the motherboard to a bit of vero board and mount on the back plate of the case.

[beamrider]

Looks good, he's chopped a few too many corners for me personally though i.e. a cassette connector and an external switch block for memory configuration.

It is not beyond the skills of any hobbyist assembling this kit to move the switches off the motherboard to a bit of vero board and mount on the back plate of the case.

True, but you can't disable the built-in 3K so things like super-expander won't work? I think that would have been a complication worth having.

Also, I'm seem to recall there are some unexpanded games that don't work with 3K installed. I know you can do a POKE, but that's a bit of a pain for the average user that just wants to load up a cassette and play.

[Mike]

True, but you can't disable the built-in 3K so things like super-expander won't work? I think that would have been a complication worth having.

I suppose the new mainboard explicitly pulls up the /RAMx signals on the cartridge port to silence external +3K RAM expansions, like the one of Super Expander. I took the very same precautions with my VFLI mod. So your concerns get an unexpected answer: of course the Super Expander cartridge still works, but it now uses the internal +3K RAM expansion instead.

Also, I'm seem to recall there are some unexpanded games that don't work with 3K installed. I know you can do a POKE, but that's a bit of a pain for the average user that just wants to load up a cassette and play.

That mainly affects machine code programs/games with a BASIC stub. Nothing that can't be cured by a simple unexpand program. With BASIC programs, neither is the screen relocated as it is with bigger RAM expansions (+8K or more), also reorganisation of the memory - to protect user defined characters from being overwritten (with POKEs to 55/56 and CLR) - works the same with both unexpanded and +3K RAM.

I did not include a switch with the VFLI mod on my VIC-20 to revert to unexpanded RAM. That should tell something.

[beamrider]

Sorry, having to type in or load a loader program before every unexpanded game is still an inconvenience too far for me. If he addresses these issues in a future version I would probably build it, but not as it stands.