Denial

Hi,

I’d like to try something similar to what Chysn has done here. I plan to start trying to fix a couple of non-working cartridges I’ve got. For that, I plan to burn the corresponding .crt file (removing first 2 bytes) to an eprom and replace, with it, the original cartridge ROM.

If I get this working, I’d like to try burning my own game to the eprom and place it in an existing cartridge.

Following the messages exchanged in this thread, I think I’ve got the .crt file (8192 bytes) correctly configured (at least I can run xvic with -cartA <filename> and it autostarts and responds OK to a soft reset (restarting the game)

But I’m not sure how to do the HW part. I have some 2764 and 27c64 eproms. I also have 2364 to 27xx adapters. Would this be the right components to use? Regarding the cartridge, I assume I’d need one for 8k configured to use memory at $A000 (that is the address where my game loads now). How can I identify, from the cartridge PCB, ROM size and loading address?

Thanks!

Lechuck wrote: ↑Thu Sep 23, 2021 12:52 pm But I’m not sure how to do the HW part. I have some 2764 and 27c64 eproms. I also have 2364 to 27xx adapters. Would this be the right components to use?

Yeah, you'd use 2764 EPROMs for your cartridges, or 28C64B* EEPROMs. You don't use a 2364 adapter for cartridges.

* Corrected

Regarding the cartridge, I assume I’d need one for 8k configured to use memory at $A000 (that is the address where my game loads now). How can I identify, from the cartridge PCB, ROM size and loading address?

It depends on the PCB. The original Commodore PCBs will have a solder blob crossing a jumper pad, with the block number indicated next to the jumper pad. Most of these are already set up for 8K at Block 5 ($A000). If you're lucky, there's already a socket.
If you get a PCB from The Future was 8-Bit, there are jumper pads clearly labeled that make it easy to set it the way you want. I use 0-Ohm SMD resistors as jumpers, since they're more widely-spaced than typical jumper pads.

Thanks a lot Chysn, that was really fast!

chysn wrote: ↑Thu Sep 23, 2021 1:32 pm Yeah, you'd use 2764 EPROMs for your cartridges, or 28C74B EEPROMs. You don't use a 2364 adapter for cartridges.

Ah, great. Much better. For some reason I thought ROMs in cartridges would be similar to the Kernal and BASIC ones...

chysn wrote: ↑Thu Sep 23, 2021 1:32 pm It depends on the PCB. The original Commodore PCBs will have a solder blob crossing a jumper pad, with the block number indicated next to the jumper pad. Most of these are already set up for 8K at Block 5 ($A000). If you're lucky, there's already a socket.

OK, perfect. I haven't openned the cartridge yet. Not sure if I'll be so lucky to find a socket. If I'm not will need to practice my disoldering skills...

Thanks again!

Hi Chysn,

I have tried with 4 cartridges (Mole Attack, Poker, Lunar Lander and Sargon II Chess) and they have 24 pins ROMS (no socket ).
They all look very similar:


I have also opened PinBall Espectacular and this one is a bit different. It has 2 ROMs (I guess it is a 16 Kb game) and, although the ROMs are also 24 pins, PCB has 4 extra holes for each ROM, so, I guess, this might be used with 24 and 28 pins ROMs:


I guess there were versions of Cartridge PCBs for 24 and for 28 pins ROMs...

I'll give it a try with one of the 24 pins (a couple of them are not working) using 27c64 EPROM and an adaptor. I have also ordered a couple of PCBs from TFW8B, in case I don't get it working with the Commodore ones. Will let you know the result... It will be funny, anyway

Thanks!

It worked!...

For this first try, I decided to use a Mole Attack cartridge. First I removed the ROM and soldered a 24 pins socket:


For the EPROM, I have used a ST M27C64A:


And this is the 2764->2364 adaptor I have used:


Bought from eBay:
https://www.ebay.es/itm/233778951283

This is how the 'Cartridge' looks like:


(Next time I should use fewer sockets, will be dificult to close the cartridge this way...)


And, once plugged in my Vicky Twenty....




Next try will be with one PCB from TFW8B. Maybe that way I'll get a cartridge I can close...

Thanks a lot for your help!

Cheers

You may want to take a look at the following thread that contains some open source PCB designs that can accommodate modern eproms directly so you don't need to mess about with adapters etc.

http://sleepingelephant.com/~sleeping/i ... 4&start=30

beamrider wrote: ↑Sat Sep 25, 2021 6:33 am You may want to take a look at the following thread that contains some open source PCB designs that can accommodate modern eproms directly so you don't need to mess about with adapters etc.

http://sleepingelephant.com/~sleeping/i ... 4&start=30

Thanks, Beamrider, very interesting. Yes, important to avoid building adapters and, also, to not being dependant on Commodore cartridge PCBs that are certainly limitted…

Cheers

Much better with one the TFW8B's PCBs



And, with the EPROM plugged in:



As I had the case from the Mole Attack game, I decided to reuse it for my new cartridge. So, after removing the label, and some cleaning and retrobrighting:



And, to get something similar to the original cartridges, I have drawn a new label...



It really works...



I have uploaded the label I have drawn, in svg format, in case anyone wants to reuse it for other games/applications

Cheers

Nice.

Are you intending to release this on cartridge?

beamrider wrote: ↑Fri Oct 15, 2021 12:58 pm Nice.

Are you intending to release this on cartridge?

No, I’m afraid not. I think it looks nice getting something close to the original case (with a modern case it doesn’t look that nice) but I don’t have more cases I can ‘reuse’. I was doing it just for fun

Cheers

Lechuck wrote: ↑Fri Oct 15, 2021 1:20 pm

beamrider wrote: ↑Fri Oct 15, 2021 12:58 pm Nice.

Are you intending to release this on cartridge?

No, I’m afraid not. I think it looks nice getting something close to the original case (with a modern case it doesn’t look that nice) but I don’t have more cases I can ‘reuse’. I was doing it just for fun

Cheers

Will you (or did you) make the ROM image available, so we can make our own Space Invaders cartridge?

chysn wrote: ↑Sat Oct 16, 2021 10:26 am Will you (or did you) make the ROM image available, so we can make our own Space Invaders cartridge?

Yes, of course!. I have attached it.

Cheers

Did you consider asking TFW8B to distribute it on cartridge, you would probably make some money by way of commission.

Lechuck wrote: ↑Sat Oct 16, 2021 10:34 am

chysn wrote: ↑Sat Oct 16, 2021 10:26 am Will you (or did you) make the ROM image available, so we can make our own Space Invaders cartridge?

Yes, of course!. I have attached it.

Cheers

Thanks! I burned it onto a 28C64B and it works great!

beamrider wrote: ↑Sat Oct 16, 2021 10:50 am Did you consider asking TFW8B to distribute it on cartridge, you would probably make some money by way of commission.

Thanks for the idea Beamrider. But, not sure if it would be legal selling it since it is 100% based in an existing game (for which, I clearly don't have the copyright). I assume it is OK offering it for free (as I'm doing here) but not sure if it would be the same if I try to earn money with it.

But, again, thanks for the idea, and for your interest.

Cheers