40 80 column cards

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cobracon
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40 80 column cards

Postby cobracon » Thu Jan 11, 2018 3:03 pm

Has anyone made a modern 40 80 card? Imagine bbs's in 80 column mode. or irc ,rss. Makes me foam at the mouth ;)

eslapion
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Re: 40 80 column cards

Postby eslapion » Fri Jan 12, 2018 3:01 pm

cobracon wrote:Has anyone made a modern 40 80 card? Imagine bbs's in 80 column mode. or irc ,rss. Makes me foam at the mouth ;)

No, but I have the Protecto 80. I would know how to clone it but it was a better investment in time to make PLAnktons and TOLBs.

The Protecto 80 is actually easy to replicate.
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orion70
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Re: 40 80 column cards

Postby orion70 » Fri Jan 12, 2018 3:45 pm

I always wondered why it was never cloned. IMO, there would be a fair amount of people who'd be interested in this. Including myself, of course :)

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Re: 40 80 column cards

Postby eslapion » Fri Jan 12, 2018 4:09 pm

orion70 wrote:I always wondered why it was never cloned. IMO, there would be a fair amount of people who'd be interested in this. Including myself, of course :)

For one thing, the ROMs have an inverted chip select pin. Until I figured that one out, I wasn't able to dump their content.

Now that I have them, this is a cluster of 74_ series of logic chips with a large number of connections, surrounding a 6545/6845 (both work). It's a long and tedious job to make the circuit board and the market is fairly small so the price tag will end up quite high.
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Re: 40 80 column cards

Postby sjgray » Fri Jan 12, 2018 8:23 pm

I started an 80-column cartridge for the C64 here:
http://www.6502.org/users/sjgray/projec ... index.html

This cartridge uses a Yamaha video chip like used in the MSX2 computers, a Yamaha sound chip, and a Link-232 inspired RS-232 circuit.
I designed this to learn about the Yamaha V9958 video chip, which is like a VIC-II on steroids, plus the FM sound. The firmware/software would still have to be written to make it all work, since it's totally different than the existing 6545/6845-based solutions. The Yamaha chip is actually more like the C128's 80-column VDC chip.

Unfortunately other projects have sidetracked my progress.

At some point once the C64 cart was working I planned to adapt it for the VIC-20. I did start it but I haven't got the correct VIC-20 cartridge edge-connector in Kicad, and I was also going to add RAM which I haven't looked into yet. If anyone wants to take on the project I'm willing to share what I've done. Or, if anyone can help me with getting the RAM added and proper cartridge port I'm still willing to work on it, but it'll be a low priority as I have a bunch of other projects ongoing.

Steve

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orion70
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Re: 40 80 column cards

Postby orion70 » Sat Jan 13, 2018 2:11 pm

Eslapion, I sorry but I cannot understand if this is really
actually easy to replicate

or if
It's a long and tedious job to make the circuit board

:)

Someone, if not yourself, should hijack Steve's undone project. If there's a market for (expensive, albeit very good) new games on cartridge, I guess most old time collectors of VIC stuff miss a 40/80 column card, and would gladly spend some bacon on it.

eslapion
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Re: 40 80 column cards

Postby eslapion » Sat Jan 13, 2018 4:42 pm

orion70 wrote:Eslapion, I sorry but I cannot understand if this is really
actually easy to replicate

or if
It's a long and tedious job to make the circuit board

:)

Imagine when teachers punished naughty school kids with having to rewrite the same sentence 200 times.

It's not 'complicated'. It's long and tedious...

That's what cloning the Protecto 80 represents. It uses only through-hole circuits and there's no copy protection per se. Everything about it is known.
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dragos
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Re: 40 80 column cards

Postby dragos » Sat Jan 13, 2018 5:20 pm

The video chip may not be easy to get in quantities, we have been considering this for two years...
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Re: 40 80 column cards

Postby sjgray » Sat Jan 13, 2018 6:04 pm

A quick look on ebay shows plenty of V9958 chips available in quantity. In the past I've purchased parts from G&C and Polida2008 without any problems. Also funkward-tech can put together the V9958 with whatever supports components you need for a fairly reasonable price (look for "yamaha v9958 kit").

6845's (or equivalent) are also easy to find.

I wish I had more time for all of my projects. The V9958 is a pretty neat chip, as is the YM sound chip. I'd like to see what they can do in a 6502 system.

Steve

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orion70
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Re: 40 80 column cards

Postby orion70 » Sun Jan 14, 2018 2:06 am

@Eslapion: ok thanks, now i got it. Too bad such a card will probably remain in my dreams.

sjgray
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Re: 40 80 column cards

Postby sjgray » Mon Jan 15, 2018 1:01 pm

Well, I've sorted out the cartridge edge connector footprint. Just need to add the RAM.
Anyone know of schematics for a simple 1-ram-chip circuit? I think I have room for a skinny-dip ram and one more chip.
It looks lke Eslapion's ram expander uses one 32K chip and a single LS'08...

The PCB is already 95% routed from the VYM64 cart. I'd just need to add the ram, fix up the connections to the vic-20 cart slot and that would be it.

Steve

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Re: 40 80 column cards

Postby eslapion » Mon Jan 15, 2018 1:24 pm

sjgray wrote:It looks lke Eslapion's ram expander uses one 32K chip and a single LS'08...

Yes. The Ultimate Expander used a 62256 SRAM IC or equivalent and a 74LS08.

Since the BLK 1,2,3 and 5 areas represent 8kBytes each, it is required to re-encode these signals for compatibility with a single 32kBytes memory chip. Using a 74LS08 or 74HCT08 to re-encode the Chip Select line and the A13 and 14 lines is as follows:

!CS = (BLK1 AND BLK2) AND (BLK3 AND BLK5) - 3 gates

A14 = BLK1 AND BLK2 - signal from 1st gate used above

A13 = BLK1 AND BLK3 - 4th gate from 74_08

For full electrical compatibility use ONLY 74LS08 or 74HCT08.

DO NOT use 74HC08!
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sjgray
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Re: 40 80 column cards

Postby sjgray » Mon Jan 15, 2018 5:31 pm

eslapion wrote:
sjgray wrote:It looks lke Eslapion's ram expander uses one 32K chip and a single LS'08...

Yes. The Ultimate Expander used a 62256 SRAM IC or equivalent and a 74LS08.

Since the BLK 1,2,3 and 5 areas represent 8kBytes each, it is required to re-encode these signals for compatibility with a single 32kBytes memory chip. Using a 74LS08 or 74HCT08 to re-encode the Chip Select line and the A13 and 14 lines is as follows:

!CS = (BLK1 AND BLK2) AND (BLK3 AND BLK5) - 3 gates

A14 = BLK1 AND BLK2 - signal from 1st gate used above

A13 = BLK1 AND BLK3 - 4th gate from 74_08

For full electrical compatibility use ONLY 74LS08 or 74HCT08.

DO NOT use 74HC08!


Nice! Appreciated. I'll update my schematics and you can take a look to see if I got it right.

BTW, Nice meeting you at World of Commodore 2017!

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Re: 40 80 column cards

Postby sjgray » Wed Jan 17, 2018 11:47 am

I have completed a preliminary design of the VIC-20 version of my VYMS64 cart.
This includes V9958 Video with 64K VRAM, YM2413 Audio, 6551 ACIA RS-232, plus 32K RAM for main VIC memory.

Schematics and info is available on my VYMS web page: http://www.6502.org/users/sjgray/projec ... index.html

I need to do additional tweaking, including making sure all parts and footprints are correct before making a board run. I also need to verify operation of the RS-232 circuit. This applies to both the C64 and VIC-20 versions.

This is NOT a commercial product, but I may be willing to sell blank pcb's when the design is fully tested. I do fully intend to complete both VYMS64 and VYMS20 when I get time. As this is a hobby there are no guarantees.

Comments, feedback etc are welcome, but don't ask me for a timeline ;-)

Steve

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Re: 40 80 column cards

Postby eslapion » Wed Jan 17, 2018 12:00 pm

sjgray wrote:BTW, Nice meeting you at World of Commodore 2017!

Nice meeting you too! :wink:
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