Lord-Chaos Posted January 27, 2003 Share Posted January 27, 2003 I have some Telegames carts which contain EPROMs. These games are Bump n Jump and Quest for Quintana Roo , both 8K. It is maybe possible to use the boards and the EPROMs for homebrewn games. I can desolder the EPROMs and erase them.I also have an EPROM Burner , it´s for a C64 , but it´s good enough for 8K.C64 Floppies can be easily connected to a PC , I already have the cable. Both I don´t know which kind of bankswitching these games use. Both games are Telegames PAL versions (very common in Europe). If it´s possible to use the same bankswitching,these carts could be used for own 8K games or 8K games using the same bankswitching. Or is it possible to use only 2/4 K of the EPROMs although the carts are 8K ? BTW : If anyone in Germany is interested in making carts for the 2600 or the ATARI XL/XE or maybe even the 7800 oder the Colecovision you may contact me. Thimo Quote Link to comment Share on other sites More sharing options...
Cupcakus Posted January 27, 2003 Share Posted January 27, 2003 It is maybe possible to use the boards and the EPROMs for homebrewn games. Yes... but probably at a greater cost then you can buy custom made PCB's for the same task. Both I don´t know which kind of bankswitching these games use. Both games are Telegames PAL versions (very common in Europe). Both games used F8 bankswitching... the most common 8k bank switching scheme... all 8k homebrews use this method. What is interesting is the M-Network Bumb 'n Jump is E7 bankswitched, which is quite different then F8, and the ROM was dumped at 16k. Very interesting.... But the Telegames version is definetly F8. If it´s possible to use the same bankswitching,these carts could be used for own 8K games or 8K games using the same bankswitching. As long as the EPROM's you use have the same pinout as the EPROM used before, absolutely. Or is it possible to use only 2/4 K of the EPROMs although the carts are 8K ? No... that is not possible, the bankswitch logic looks for specific addresses x1FF7 and x1FF8 to know which bank to switch to. If you placed a 4k game onto the EPROM that had an instruction, or data in either of those addresses, the cart will bankswitch and crash. However not every game has data in that area... so it may work on certain games. Quote Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted January 27, 2003 Share Posted January 27, 2003 No... that is not possible, the bankswitch logic looks for specific addresses x1FF7 and x1FF8 to know which bank to switch to. If you placed a 4k game onto the EPROM that had an instruction, or data in either of those addresses, the cart will bankswitch and crash. But you can put multiple copies of the same game into the card. Then, when hitting such an address, the cart would just switch to another bank containing the same code. Quote Link to comment Share on other sites More sharing options...
Lord-Chaos Posted January 27, 2003 Author Share Posted January 27, 2003 It is maybe possible to use the boards and the EPROMs for homebrewn games. Yes... but probably at a greater cost then you can buy custom made PCB's for the same task. This is the problem - don´t know where to get PCBs in Europe and were to get cheap 8K Eproms.There already are EPROMs in the carts and there are the boards AND they are easy to open and removing the label is no problem. It´s difficult to find 4 or 8K Eproms today and old PC BIOS EPROMs are usually bigger. So this should be a cheap source of EPROMs. The problem with the 4K games : If I or somebody else writes a 4K game , the easiest solution would be not to use these addresses so that the cart does not bankswitch or make a 2-in-1 cart or something like that. Thimo Quote Link to comment Share on other sites More sharing options...
CPUWIZ Posted January 27, 2003 Share Posted January 27, 2003 Thimo, hast Du schon mal von Conrad gehoert ? Conrad Electronics EPROM's Quote Link to comment Share on other sites More sharing options...
Cupcakus Posted January 29, 2003 Share Posted January 29, 2003 No... that is not possible, the bankswitch logic looks for specific addresses x1FF7 and x1FF8 to know which bank to switch to. If you placed a 4k game onto the EPROM that had an instruction, or data in either of those addresses, the cart will bankswitch and crash. But you can put multiple copies of the same game into the card. Then, when hitting such an address, the cart would just switch to another bank containing the same code. I thought of this Thomas... but I thought it was determined that the data read from the 1ff7 & 1ff8 area's of ROM would not be reliable because of the switch... Quote Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted January 29, 2003 Share Posted January 29, 2003 I thought of this Thomas... but I thought it was determined that the data read from the 1ff7 & 1ff8 area's of ROM would not be reliable because of the switch... AFAIK you just would not know from which bank you are reading. But that wouldn't matter, because both banks would be identical. But I'm not 100% sure about this. Quote Link to comment Share on other sites More sharing options...
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.