40/80 column cartridge

carlsson · Post by **carlsson** » Sat Apr 01, 2006 5:06 am

See also Mayhem's dumping thread in the General section; Mike posted some POKEs and SYSes useful for quick dumping of a memory block.

ral-clan · Post by **ral-clan** » Sun Apr 02, 2006 7:05 am

saundby wrote:Slick trick with the cart case, btw. And yes, I see why you need a low-profile motherboard. You've got about fourteen more inches in width for your space than I've got, which is why I don't have my green screen going again yet.

But yes, that C= monitor stand is =low=. Perhaps you could give yourself another half inch by putting some thick rubber feet on the bottom of it? I've used that trick more than once myself.

Ah! Rubber feet. What a simple yet ingeneous idea!

As for the monitor stand. It is very low, but since the whole desk and monitor stand is rather scarce original Commodore gear made just for the VIC-20/C64, I would prefer to use it rather than make a custom job. (Part of my enjoyment in using the VIC-20 is actually using the original gear - i.e. having an authentic 'atmosphere' - kind of goofy I know, but I'm nostalgic that way).

ral-clan · Post by **ral-clan** » Sun Apr 02, 2006 7:07 am

saundby wrote: Here's an article that will help explain some things:
http://www.atarimagazines.com/compute/i ... modore.php

Unfortunately that link appears to be broken right now (Sunday morning EST).

CORRECTION: Working now.

ral-clan · Post by **ral-clan** » Wed Apr 29, 2009 3:38 pm

Hi guys, I finally dumped the ROM from my DATA-20 40/80 column board ("Display Manager").

Hopefully there's some interesting stuff in there.

http://www3.sympatico.ca/clarke-santin/ ... 20_rom.zip

carlsson · Post by **carlsson** » Wed Apr 29, 2009 3:54 pm

Has anyone reverse engineered those 40/80 column cartridges? Maybe someone even considers developing a brand new one, ideally one that does colour and custom graphics and/or sprites. Or would that be cheating on the VIC chip?

ral-clan · Post by **ral-clan** » Wed Apr 29, 2009 4:35 pm

Those who downloaded it in the last hour before this message was posted, please download again. I realized afterward that I forgot to re-enable the switch on my multi-slot expander before dumping block 5.

6502dude · Post by **6502dude** » Wed Apr 29, 2009 6:55 pm

carlsson wrote:Has anyone reverse engineered those 40/80 column cartridges?

It would not be difficult to do. It is very simple circuit based on 6845 CRT chip.

carlsson wrote:Maybe someone even considers developing a brand new one, ideally one that does colour and custom graphics and/or sprites.

I sort of did, but I did not intended to use it for Vic-20

http://sleepingelephant.com/ipw-web/bul ... c&start=15

The downside of 40/80 column carts is that everything is copied from internal video memory to video memory on card in expansion slot. This is needed to maintain compatibility witd software for screen writes.
All of these video ram copies slow down Vic-20 by about 30%-40%

The other downside is that it takes up expansion slot, and who really wants to remove their MegaCart once they have it?

gklinger · Post by **gklinger** » Wed Apr 29, 2009 7:18 pm

6502dude wrote:The other downside is that it takes up expansion slot, and who really wants to remove their MegaCart once they have it?

That's no joke to me. I stopped looking for a 40/80 column unit for my VIC-20 once I placed the order for my MC. As a consolation, you guys included the 40 column terminal in the MC so I can't complain.

carlsson · Post by **carlsson** » Thu Apr 30, 2009 1:34 am

I dunno, they would serve two rather different tasks. But I know if I want to make games for a 6502 based computer with higher resolution, hardware sprites and so on, I already own at least five distinct systems to choose from.

Schema · Post by **Schema** » Thu Apr 30, 2009 9:10 am

gklinger wrote:
6502dude wrote:The other downside is that it takes up expansion slot, and who really wants to remove their MegaCart once they have it?
That's no joke to me. I stopped looking for a 40/80 column unit for my VIC-20 once I placed the order for my MC. As a consolation, you guys included the 40 column terminal in the MC so I can't complain.

My solution is to have two VIC-20s. One with the MegaCart (and uIEC), and another one for 40/80 column cartridges, Ham radio cartridges and other stuff.

gklinger · Post by **gklinger** » Thu Apr 30, 2009 2:11 pm

I'm trying to get away from having two (or three or four or...) of everything.

amramsey · Post by **amramsey** » Thu Apr 30, 2009 7:27 pm

gklinger wrote:I'm trying to get away from having two (or three or four or...) of everything.

Ha ha... my sixth vic-20 just showed up the mail today.

I started off wanted a backup for my original vic-20 but now I can't help myself when I see a poor little one just waiting for someone to love it.

gklinger · Post by **gklinger** » Thu Apr 30, 2009 7:39 pm

amramsey wrote:Ha ha... my sixth vic-20 just showed up the mail today.

Yeah, I was bidding on that VIC-20 for a friend.

Schema · Post by **Schema** » Fri May 01, 2009 7:31 am

gklinger wrote:I'm trying to get away from having two (or three or four or...) of everything.

We'll have to start plans for a MegaCart 2.0 with 10x the games, 40/80 column output, Ethernet, VGA, and coffee maker.

rhurst · Post by **rhurst** » Fri May 01, 2009 8:07 am

I would love to see Mega-Cart-V, whereas V stands for virtual. All the nifty engineering in Mega-Cart extended to an emulator format -- no VIC 20 required. EEPROM burning optional.