Tempest Posted July 9, 2001 Share Posted July 9, 2001 Ok, by now someone else should have recieved their EPROM Tester/Prototype thing from ebay (you know, the 2600/7800/8-bit EPROM chips). Has anyone found anything on those EPROMs yet? I have mine (a 7800 tester) but it needs a mod before it will play EPROMs so we wont know for a bit. I was just curious... Tempest Quote Link to comment Share on other sites More sharing options...
Eckhard Stolberg Posted July 10, 2001 Share Posted July 10, 2001 Your Karateka prototype looks as if the EPROMs are socketed. This game is 48K big, so one of the chips should be 32K and the other one 16K. I think the one labeled HI is the 32K chip and is also mapped in at the correct address range. You could try to carefully lever this chip out with a flat screwdriver, making sure that you don't bend any of the pins. Then you could put in your new EPROMs into the socket. (The notch must point into the same direction as it is on the chip currently in the socket.) This would allow you to try out the EPROMs on a real 7800 console. Ciao, Eckhard Stolberg Quote Link to comment Share on other sites More sharing options...
Tempest Posted July 10, 2001 Author Share Posted July 10, 2001 That's not a bad idea, I'll give it a shot when I get home. I'm still not holding out much hope though. So does that mean the 16K chip is just some generic chip that all the games have? BTW, did you read the message on Tom Sloper's webpage where he said that that's his handwriting on the label? Let that be a lesson to all the nay sayers out there who said it looked "funny" (you know who you are ). Tempest Quote Link to comment Share on other sites More sharing options...
Eckhard Stolberg Posted July 10, 2001 Share Posted July 10, 2001 No, the 16K chip contains additional data for Karateka. But if the games on your new EPROMs are only 32K big, they wouldn't expect any data at the address range where the 16K chip is mapped in, and therefore not access it. So there should be no problem if you just leave it in. If the EPROMs contain different versions of Ballblazer, they would try to access the POKEY chip at this address range though. But that shouldn't be a problem either, except that you wouldn't get any sound of course. Ciao, Eckhard Stolberg Quote Link to comment Share on other sites More sharing options...
Tempest Posted July 10, 2001 Author Share Posted July 10, 2001 Interesting. How do you know that they're only 32K games on those EPROMs (not that I'm doubting you, I'm just curious)? Speaking of which, what games required more than 32K? Tempest Quote Link to comment Share on other sites More sharing options...
Eckhard Stolberg Posted July 10, 2001 Share Posted July 10, 2001 I don't know. I'm just guessing. The 6502C processor in the 7800 can only access 64K. For a simple design the first 16K are reserved for the MARIA registers and the 4K of internal RAM. Therefore the 7800 can have games with up to 48K. Anything bigger than that needs a form of bankswitching. EPROMs with 28 pins can have a maximum of 32K. (8K and 16K EPROMs also come in this size.) Since they came with the POKEY board, I suppose they are meant to work in it. Again for the simpleness of design the POKEY uses a full 16K of address space, even though it only has 16 registers. Therefore all games that are supposed to work on the Ballblazer board can have a maximum of 32K. Ciao, Eckhard Stolberg p.s. I don't have my 7800 bankswitching list handy right now, but if you want to find out about the game sizes, you could just download the ROMs from this site. [ 07-10-2001: Message edited by: Eckhard Stolberg ] Quote Link to comment Share on other sites More sharing options...
Tempest Posted July 10, 2001 Author Share Posted July 10, 2001 Well I pried out the chip and plugged my EPROM in. What could be on that chip? Is it Klax? Was it Sky Fox? Maybe it's Electro Cop... The answer? Nada! Zip Zero Zilch! As far as I can tell those chips are permently scrambled or had nothing on them to begin with. I suppose it could just be that my Karateka board just isn't up to handling these EPROMs but it isn't looking good. Maybe we'll get some answers when I get them dumped but it's looking bleaker than ever now... Tempest Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted July 10, 2001 Share Posted July 10, 2001 Too bad Tempest... I know I was hoping you might find some kick butt proto 7800 game that we didn't even know existed. But you kind of expected this would be the case with them...they are old...don't have stickers over the glass...and probably weren't handled real well. Oh well...perhaps something can be found from them sometime. You could always send me those eproms and your karateka board..and I can dump them?! Quote Link to comment Share on other sites More sharing options...
Eckhard Stolberg Posted July 11, 2001 Share Posted July 11, 2001 While it seems most likely that these EPROMs are blank or corrupted, there still is a small chance that the programs on them just didn't contain a proper signature key yet and therefore wouldn't work on a normal 7800. Afterall the first version of the 7800 development system is said to have come with a BIOS without the encryption check, and sending in the code to Atari for every revision would have been pretty tedious, especially since Tom Sloper says he was the only person at Atari at the time dealing with the 7800 programmers. Ciao, Eckhard Stolberg 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.