How small could a fully functional Vic 20 be?

[Gary_Leeds]

Comparing the size of circuit boards at work today and we have some that do the same job but made about 25 years apart and the size reduction is amazing.

This got me thinking. Using only direct replacement parts or where no replacement is available, original Commodore/MOS chips (i.e. no FPGA cheating), how small could a fully functional Vic 20 board be? And by fully funtional I mean with serial, datasette, IEC, video, joystick and cart ports all present.

There are a lot of the chips on the vic that now have surface mount replacements that are a 10th of the size, along with much smaller resistors and capacitors. Even the roms could be blown onto much smaller devices. you can get a smaller 6502 so all that would need to stay original would be the Vic specific chips

I think by having a top loading cart slot, the whole main board could come down by at least half. or if you moved slots to the right side of the board you could keep it back loading

One for Jim Brain I think

[TarkaTOtter]

I have an apple 1 replica that is 5 chips in size about the size of an Iphone.

I would love a vic 20 that cold fit into the size of a Dummies book

Vic 20 for Dummies with all the ports and a PC keyboard socket

I think you would need fpga for the fancy Vic chip?

Tarka

[English Invader]

A standard reset button might be a possibility as well. I recently bought a VIC that's been modded in this way, so it can be done.

I don't see any need to make the VIC smaller, though. As computers go, it's not that big. It fits quite nicely on my coffee table along with the datasette. The 1541 I keep on a small cardboard box beside it. All in all, it's not a bad setup.

[Gary_Leeds]

Looking into it the 6580 and 6522(x2) are the ones that would have to stay the original size (and be stripped from a donor Vic), everything else can have a newer version which is much smaller than the original.

A "Vic20 for dummies" size should be possible, but what about the keyboard?

[Gary_Leeds]

A standard reset button might be a possibility as well. I recently bought a VIC that's been modded in this way, so it can be done.

I don't see any need to make the VIC smaller, though. As computers go, it's not that big. It fits quite nicely on my coffee table along with the datasette. The 1541 I keep on a small cardboard box beside it. All in all, it's not a bad setup.

My thoughts behind as to what it could be used for is going back to the C64 laptop that needed the main board cutting up to make it fit into a reasonable size case. I know you could do it with FPGA designs on a board the size of a cd case but is that retro computing or emulation? My idea would be to take the Vic as is and just shrink it a bit with more modern and reliable components

As for the built in reset button, that would be a given, along with probably an IEC/SD drive designed straight onto the IEC bus, plus switchable ram expansion (thats if I ever did go for the laptop idea)

[Jeff-20]

It is an interesting idea, but the best thing about the VIC 20 is the feel of it under my hands. I like the keyboard and the form.

A more interesting idea for me would be cramming all of normally external add-ons and accessories into the VIC's current case. Imagine a small door on the side where a tape slides in sideways like a car's tape deck; a slim disk door similar to a Mac's CD entry; well, everything expect a printer.

[carlsson]

And by fully funtional I mean with serial, datasette, IEC, video, joystick and cart ports all present.

Even with a top-loading cartridge slot, you need to find space for all the other connectors. I suggest a keyboardless box using all four sides of it:

Back side: power, video, user port
Front side: cartridge, power button
Right side: joystick, tape
Left side: keyboard, serial

I assume you would use a DB25 to connect the external keyboard. In order to not have the connectors allocate too much space, I would arrange the four on left/right sides as above.

Now this is purely hypothetical. The 6502, 6522's, 6560/61 and ROMs take quite a lot of space. Perhaps you can find smaller replacements for the ROMs and RAM without going into programmable arrays.

Anyway, I'm really fond of the idea of a detachable keyboard. I've seen some homemade hacks but none in a larger scale. Imagine how bizarre a VIC-20D (think C128D) would have been. Perhaps a VIC-20T for Tape, a homage to the first PET 2001.

[TarkaTOtter]

If it was a keyboard-less box about the size of a Wii I can convince my wife to let me leave it under the TV (beside the Wii) and I could just plug in the megacart and Joystick to play or a keyboard to write code.

I think a standard PC keyboard with a decoder chip would mean only 1 keyboard that can be used by Vic20D or my laptop or the Apple 1 replica
(see http://www.brielcomputers.com/replica1.html)

I would love to own some setup like that - at the moment my Vic is boxed up and only used about twice a month (although that will change when I get my Megacart)

[carlsson]

Jim Brain has made an interface C=Key that I believe lets you connect a PC keyboard to a Commodore computer, mostly or fully programmable too. I'm not sure if it is produced and for sale yet.

[nbla000]

If it was a keyboard-less box about the size of a Wii I can convince my wife to let me leave it under the TV (beside the Wii) and I could just plug in the megacart and Joystick to play or a keyboard to write code.

It's incredible how Mega-Cart increase creativity

[Pedro Lambrini]

There is a thread (started by Jim Brain) regarding manufacturing cart cases. Maybe it wouldn't be so hard to create a case for the Vics keyboard. There was a keyboard case that allowed you to retrofit your Amiga keyboard and use it externally with a tower case...

If the Vic was in a slick wee case with the ability to use the original keyboard came about I would buy it in a heartbeat.

[Gary_Leeds]

Well there is a case for the keyboard that can kind of be used, its called a C64c

As Carlsson says nothing can be done about the 6522 and 6560/1 but there are 65c02 chips that are a lot smaller and the roms can be put on smaller surface mount roms and the ram could use a single smaller chip if you rerouted the tracks, if not then there are much smaller replacement chips available.

Can anyone recommend a decent PCB design software that has a lot of default components built in? I might have a look at converting one of the schematics just to see

[Pedro Lambrini]

This is a bit OT but maybe someone should produce a Vic version of this:

http://tinyurl.com/cv38xr

It would mean you could use your old motherboard and still have a small footprint...

[Gary_Leeds]

Pedro, thats one of the reasons I started to look into this.

The C64 motherboard has been cut up, ports removed and butchered to fit in there, much as most of Bens stuff is. The guy is a wizz at putting things in cases when they should not fit. Rather than hacking the function keys off and putting them round the 1541MkIII screen I was wondering if a plus 4 keyboard could be made to work? Much smaller but still with the basic feel of a Vic keyboard.

Edit: just looked at the matrix of the plus 4 keyboard and 90% of the keys seem to match but its the last 3 rows of the matrix that fails to match (cursor keys, +, -, home and @) so would need the tracks redoing to make that work

[carlsson]

65C02 may not support the exact same set of op-codes and possible side effects though. If I recall correctly, all the illegal op-codes have been NOP:ed in the 65C02, and a couple new ones were added. I don't know about the demo and game coders, if they use any illegal instructions but you may end up with a slight bit of incompatibility.

Anyway, if you make a multi-layered circuit board, can't you place custom chips both on top and bottom of the board? You just need a way to secure it to the case.