Omegamatrix Posted October 23, 2008 Author Share Posted October 23, 2008 The moon patrol roms are the same rom. Nothing is different between them. Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 24, 2008 Author Share Posted October 24, 2008 The Stand Alone Test Cart and Diagnostic Test Cart 2.6 differences are interesting. The roms are different. No question about it since there is a byte difference at $FCEE. But since 2k roms are repeated in a 4k space, the same code appears between $F000 - $F7FF (2k of rom) as address $F800 - $FFFF (2k of rom). Now look at what is happening at this point: Stand Alone Test Cart STX SWCHA ; 4 JSR LFF04 ; 6 Diagnostic Test Cart 2.6 STX SWCHA ; 4 JSR L7F04 ; 6 These are jumping to the same routine, but in different halves of the 4k rom. There is no difference in functionality, yet the code is different between these two roms. Now the interesting part: F in binary 1111 7 in binary 0111 You can see there is one "bit" difference between the two. Bit rot could explain the difference between the two roms. I would expect that the Stand Alone Test Cart is the actual good dump as all the other JSR's (Jump to Subroutine) and JMP's (Jump) use $Fx instead of $7x as the high address in the call. The funny thing is even with this bit rot, the game functions 100% the same, by chance. Quote Link to comment Share on other sites More sharing options...
Tempest Posted October 24, 2008 Share Posted October 24, 2008 Was this test cart from my collection? Tempest Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 24, 2008 Author Share Posted October 24, 2008 I only see the 2.0 version of the Diagnostic Test Cart in your collection, Matt. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted October 24, 2008 Share Posted October 24, 2008 How does it compare to the PAL test cartridge? I would guess some of the code would be reused from the NTSC one. Mitch Quote Link to comment Share on other sites More sharing options...
Nukey Shay Posted October 24, 2008 Share Posted October 24, 2008 The Stand Alone Test Cart and Diagnostic Test Cart 2.6 differences are interesting. The roms are different. No question about it since there is a byte difference at $FCEE. But since 2k roms are repeated in a 4k space, the same code appears between $F000 - $F7FF (2k of rom) as address $F800 - $FFFF (2k of rom). Now look at what is happening at this point: Stand Alone Test Cart STX SWCHA ; 4 JSR LFF04 ; 6 Diagnostic Test Cart 2.6 STX SWCHA ; 4 JSR L7F04 ; 6 These are jumping to the same routine, but in different halves of the 4k rom. There is no difference in functionality, yet the code is different between these two roms. Now the interesting part: F in binary 1111 7 in binary 0111 You can see there is one "bit" difference between the two. Bit rot could explain the difference between the two roms. I would expect that the Stand Alone Test Cart is the actual good dump as all the other JSR's (Jump to Subroutine) and JMP's (Jump) use $Fx instead of $7x as the high address in the call. The funny thing is even with this bit rot, the game functions 100% the same, by chance. This makes no difference to the hardware. 1111 and 0111 both have the important low bit set to 1 (that is the only bit that the hardware uses in the upper nybble of the MSB to determine if the address is RAM or ROM. It's not "by chance" that it works. Address $FF04 - the 2600 "sees" $1F04 (rom) Address $7F04 - the 2600 "sees" $1F04 (rom) It would be an entirely different story if the rightmost bit of the nybble were set to zero, however. In that case, the address would be translated as $0F04 (ram). It could have been "bit rot"...on the other hand, it could have been a bad dump that accidentally lost the high bit. Quote Link to comment Share on other sites More sharing options...
+batari Posted October 24, 2008 Share Posted October 24, 2008 F in binary1111 7 in binary 0111 You can see there is one "bit" difference between the two. Bit rot could explain the difference between the two roms. I would expect that the Stand Alone Test Cart is the actual good dump as all the other JSR's (Jump to Subroutine) and JMP's (Jump) use $Fx instead of $7x as the high address in the call. The funny thing is even with this bit rot, the game functions 100% the same, by chance. That's probably not bit rot. Changing zeros to ones happens during erasure, and is a passive process that can happen naturally. Changing ones to zeros happens during programming and is an active process that occurs under very specific conditions. Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 24, 2008 Author Share Posted October 24, 2008 This makes no difference to the hardware. 1111 and 0111 both have the important low bit set to 1 Yep, you are right. I had it in my head that I was looking at $F7FF. My mind was playing tricks on me. The $7FFF address would go to the same place in the rom as the 3 high bits in the high octect are don't care conditions since they are not addressed. Were games still being hard coded in hex back then or did they have assemblers? If it was an assembler translating a label then its very unlikely that the $7F value occured (would have been $FF instead). Quote Link to comment Share on other sites More sharing options...
+Mitch Posted October 24, 2008 Share Posted October 24, 2008 2600 PAL diag ROM for comparison. Mitch 2600paldiag.zip Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 25, 2008 Author Share Posted October 25, 2008 This is interesting. The PAL rom is 4k, so I split it in half. The roms are not the same at all however. They will have to be compared to each other and the NTSC one to see if one is perhaps an earlier version stuck inside. Diagnostic_Test_Cart_2_6_PAL__2k_halves.zip This is each comparision: ;----------------------------------------------------------------------------- Stand Alone Test Cart (NTSC) ; LFF04 subroutine is called ~ nine places LFCEC: JSR LFF04 Diagnostic Test Cart ver 2.6 (NTSC) ; same as Stand Alone Test Cart except for one byte at $FCEE ; L7F04 subroutine is called once, subrountine LFF04 is called ~ eight places LFCEC: JSR L7F04 Diagnostic Test Cart ver 2.6 (PAL) $F000 - $F7FF ; Because of differences between PAL and NTSC rom, subroutine is now at address $FEF1 ; LFEF1 subroutine is called ~ nine places LFCDC: JSR LFEF1 Diagnostic Test Cart ver 2.6 (PAL) $F800 - $FFFF ; Because of differences between the 2k halves of the PAL rom, subroutine is now at address $FEFF ; LFEF1 subroutine is called ~ nine places LFCEA: JSR LFEFF ;----------------------------------------------------------------------------- So the Diagnostic Test Cart (NTSC) is the only one that has an odd ball address. All the other roms use the same label nine times. I would say it is pretty convincing that the dump is not good. BTW the routine they are all calling is just a 17 line delay: LDX #$10 .loopDelay: STX WSYNC DEX BPL .loopDelay RTS Just what does the test cart exactly do anyhow? IIRC AtariProtos said they think extra equipment might be required to make it work properly. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted October 25, 2008 Share Posted October 25, 2008 Regarding bitrot, if I remember correctly, the NTSC 2600 diag cart was released on ROMs not EPROMs. Not sure about the PAL ones. I've never opened either my NTSC or PAL diag carts becuase I didn't want to destroy the label. Could be a bad dump though. The extra hardware that is mentioned are the joystick port loopback plugs. From what I remember you only need them for the joystick port test. Mitch Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 25, 2008 Author Share Posted October 25, 2008 Are they sliding trap door? Would you be able to see a hex inverter inside or is it too small a gap? I would like to learn more of bit rot too. We did a little bit of how transistors strore a charge in school, but honestly I can't remember the connections or if that is how an eprom is done. Failure of prom is a different story. I know Bomb carts were bad for it, but I don't know why or what exactly happens to them. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted October 25, 2008 Share Posted October 25, 2008 Yes, they have the sliding dust cover. Pretty much impossible to tell without opening them up. Mitch Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 25, 2008 Author Share Posted October 25, 2008 Mitch do you have the 2.6 version? I'm wondering if you could do a dump of it. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted October 25, 2008 Share Posted October 25, 2008 Mitch do you have the 2.6 version? I'm wondering if you could do a dump of it. NTSC 2.6? Yeah, that's the one I have, probably won't have time to dump it till later this weekend though. Mitch Quote Link to comment Share on other sites More sharing options...
Tempest Posted October 25, 2008 Share Posted October 25, 2008 Just what does the test cart exactly do anyhow? IIRC AtariProtos said they think extra equipment might be required to make it work properly. There were joystick port plug shorters for example, I have a pair of them. There may have been other things as well, but I don't have the manual. Tempest Quote Link to comment Share on other sites More sharing options...
Rom Hunter Posted October 25, 2008 Share Posted October 25, 2008 Tempest, Do you also have the ROM of the 4.2 version? Quote Link to comment Share on other sites More sharing options...
Tempest Posted October 25, 2008 Share Posted October 25, 2008 Tempest, Do you also have the ROM of the 4.2 version? Yes it should be in the directory called Test Cart (no idea why I separated them). I actually have the EPROM right here and it's labeled 4.2 DOM 6-1-82. Tempest Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 25, 2008 Author Share Posted October 25, 2008 Just what does the test cart exactly do anyhow? IIRC AtariProtos said they think extra equipment might be required to make it work properly. There were joystick port plug shorters for example, I have a pair of them. There may have been other things as well, but I don't have the manual. Tempest I looked at a few pictures on Atarimania and see what you mean. Has the manual for the cart ever been scanned? I'm curious what pins are grounded, and if the led turns on each time something is tested, etc.. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted October 25, 2008 Share Posted October 25, 2008 I looked at a few pictures on Atarimania and see what you mean. Has the manual for the cart ever been scanned? I'm curious what pins are grounded, and if the led turns on each time something is tested, etc.. The 2600 service manual was scanned to a PDF by atariguide.com, you can download it from there. Mitch Quote Link to comment Share on other sites More sharing options...
Rom Hunter Posted October 25, 2008 Share Posted October 25, 2008 Tempest, Do you also have the ROM of the 4.2 version? Yes it should be in the directory called Test Cart (no idea why I separated them). I actually have the EPROM right here and it's labeled 4.2 DOM 6-1-82. I see. That brings me to my next question: What exactly is wrong with these? non_working_proto_dumps.zip Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 25, 2008 Author Share Posted October 25, 2008 I looked at a few pictures on Atarimania and see what you mean. Has the manual for the cart ever been scanned? I'm curious what pins are grounded, and if the led turns on each time something is tested, etc.. The 2600 service manual was scanned to a PDF by atariguide.com, you can download it from there. Mitch That explains the 'blue" shortening plugs as they are mentioned in section 3, testing and troubleshooting. I saw a picture of the blue plugs here, but I thought they were a homemade job at the time as the rest I saw were black (on Atarimania). http://cgi.ebay.com/Atari-2600-service-car...1QQcmdZViewItem Quote Link to comment Share on other sites More sharing options...
Omegamatrix Posted October 25, 2008 Author Share Posted October 25, 2008 Tempest, Do you also have the ROM of the 4.2 version? Yes it should be in the directory called Test Cart (no idea why I separated them). I actually have the EPROM right here and it's labeled 4.2 DOM 6-1-82. I see. That brings me to my next question: What exactly is wrong with these? non_working_proto_dumps.zip LOTR, Ewok, and Miner all seem to work no problem. What problems were you having with these? Quote Link to comment Share on other sites More sharing options...
+Mitch Posted October 25, 2008 Share Posted October 25, 2008 Tempest, Do you also have the ROM of the 4.2 version? Yes it should be in the directory called Test Cart (no idea why I separated them). I actually have the EPROM right here and it's labeled 4.2 DOM 6-1-82. I see. That brings me to my next question: What exactly is wrong with these? non_working_proto_dumps.zip Gremlins was not joined correctly. Here is the corrected version. The others mostly just need the bankswitching specified. Fatal Run I believe needs to be reordered. I was not able to get ms pacman or the diag working and I don't have any more time to look at them right now. Mitch Gremlins31284.zip Quote Link to comment Share on other sites More sharing options...
Rom Hunter Posted October 25, 2008 Share Posted October 25, 2008 Tempest, Do you also have the ROM of the 4.2 version? Yes it should be in the directory called Test Cart (no idea why I separated them). I actually have the EPROM right here and it's labeled 4.2 DOM 6-1-82. I see. That brings me to my next question: What exactly is wrong with these? non_working_proto_dumps.zip LOTR, Ewok, and Miner all seem to work no problem. What problems were you having with these? They don't seem to work in Z26. But I noticed they do to work in Stella. I will include Miner Prototype and LOTR (Earlier). Is Ewok Adventure (NTSC,F6) a hack/conversion or something? Fatal Run (NTSC) , Gremlins 2-12-84, MsPacMan 920 and Test Cart (Dom42) 06-01-82 do nothing, though. 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.