February 22nd, 2018
Atari Xegs (#1) Change the internal game
As some of you may know, the Xegs has Missile Command built in. Which activates when the keyboard isn't plugged in. I'm experimenting with changing this game to another 8KB game.
Unlike several other Atari 8bit computers. I'm making presumptions that the ic contains the OS (16KB), Basic (8KB), on the same eprom. As their are no independent ic identified as to the ic containing the basic kernel on the Xegs mobo. Assuming it holds the game rom. (Edit: Source found, it does in fact contain the game rom, basic, and os). It took several tries, experimenting with the order to concatenate the 3 roms. So far only the OS and Basic have had functionality restored. Sadly, no game as of yet. I've used both generic 27256 (nmos) and TMS27c256 (cmos) eproms.
Order of concatenated files, that allowed for Basic and Self Test to be booted.
RevB.rom Basic (8KB) short hand B
SpaceInvaders.rom (8KB) short hand si
Rev4.rom OS (16KB) short hand 4
Possible combinations to concatenate the roms.
4/B/SI Failed
4/SI/B N/A
B/SI/4 Basic and Self Test accessible, so far no game.
B/4/SI Failed
SI/4/B Failed
SI/B/4 N/A
I'm using the direct rom dumps, as anything with a xex, etc have headers for emulators. This size difference would surpass the maximum of 32KB (32,768 bytes) available to a 27256 eprom.
What will happen in the next portion of the experiment. I want to verify that the missile command is in fact on the same eprom. Through a process of elimination, a new file will be concatenate with B(8KB)/B(8KB)/4(16KB) and programmed onto a 27c256 (32KB). If this works and i'm able to access Basic, self test and missile command. More digging will be required to find the missile command rom's location on the mobo.
Alternatively, if missile command does not boot and the order of B/GameRom/4 is correct. I must surmise that my game rom files tested so far, are in fact bad dumps. Testing of the rom(s) in a emulator, will then be required prior to proceeding. If the roms pass via the emulator. A eprom will be programmed as B/Missile Command/4 bin file later and giving that a try. If that works, I will continue to proceed with say Qix.
Update 1: Still February 22nd
I burned an eprom with RB/RB/R4 (Basic RevB 8KB/ Basic RevB 8KB/ OS Rev4). Inserted into the xegs, and it booted directly to Basic. Then executed the self test. Using the Reset button to access the feature. It preformed Rom Ram and Visual Audio Test. Rom Ram Test, all showed green. 2 for the Rom, and 48 dots for ram. Last 16 are reserved for special programs, as noted on February 21st, Atari 65xe (Part 3), check Manual. As before, Visual and Audio Test worked flawlessly. No game rom was observed.
Update 2: Still February 22nd
Here is where it gets confusing. So I burned a RB / Missile Command / R4. Placed it in the socket. Keyboard is not plugged in. Boots up into basic. Reset allows Self Test as usual. Turn her off and plug in the keyboard. Proceed to turn her on and the unit boots into Missile Command. This throws me back. So I figure, perhaps my previous assertion about the order was in fact wrong. So I burn another eprom. 100% guessing the first two 8KB are interchangeable in the series of 8KB/8KB/16KB. Upon turning the system with Missile Command / RB / R4. A black screen comes up with either the keyboard plugged in or not.
My short hand again
Rev4 OS = 4
RevB Basic = B
SI= Space invaders (Rom was a bad dump)
MC = Missile Command (Seen Working on Xegs)
Status of Possible combinations to concatenate roms.
4/B/SI Failed
4/SI/B -N/A-
SI/4/B Failed
MC/B/4 Failed
B/4/SI Failed
B/SI/4 -Basic and Self Test accessible, so far no game.
B/MC/4 Basic, Self Test, and MC all work.
With the oddity of Missile command booting with the keyboard plugged in, and basic booting with it unplugged.
Next on my check list. Will be going back to the B/B/4 eprom. Observing its behavior with the keyboard. This is when I wish I had an oscilloscope. May try do up an eprom with RevC Basic. As a quick search found an article by digital press identifying RevC as the version of Basic used by XE units.
Next best thing is research to find out what controls the selection between Basic and Game rom. Assuming the keyboard normally performs a loop in the connector. I need to find a diagram for the xegs. Though in the meantime, I found a diagram that I will have to look at later. Looks like you could hook up a xegs keyboard to other 15p connectors on 130xe units.
Update 3: Still February 22nd
Just felt like relaxing outside of the work shop this evening. So I decided to continue my work on the laptop. Found the rom of C101687 online. Time to do some investigating, using a hex editor. As I do believe its human error at this point. So I loaded the C101687, RevC Basic, Rev4 OS and Missile Command into individual windows. Did a quick visual comparison of several lines of code that indicated the order in which it is concatenated; Missile Command / RevC Basic / Rev4 OS. Which is a order that has not worked for me. Though in previous attempts I did try to use RevB Basic. Even with the known working Missile Command rom.
Then I remembered HxD allowed file comparison under the analysis menu. Literally 2 bytes of information are different. That exist in the Missile Command portion of the code. I'm not a programmer. Nor am I pretending to be one. Only knowing enough to fool around with this editor and figure stuff like this out. Again, its half the fun.
Line 000011C0
C101687 original rom
BD 51 FB C9 3A B0 0A C9 30 90 06 E9 30 85 86 10
My concatenated rom
BD FE FE C9 3A B0 0A C9 30 90 06 E9 30 85 86 10
So tomorrow I will be burning my own concatenated rom. Testing it and see how it turns out. As all my previous concatenated files were using RevB basic. Not sure if this would have made any issues. Though, Id rather work on this before making modifications to hardware after doing more research.
On the plus side, this may also resolve the issue that I had created in previous attempts. With the Basic being first 8KB portion of the 32KB rom. Causing it to boot with no keyboard attached. Then Missile Command booting with the keyboard attached.
Update 4: Yeap, its still the 22nd. Quick Update
Decided I need to go back into the workshop. I fervently needed to know the burning question in my head. If those two bytes would be at fault for the issues i've been experiencing. That being very unlikely, as it's already been seen working.
On the other hand, was it the RevB Basic I had used, vs RevC Basic. The new concatenated file that minus those two bytes is identical to the original C101687. Indeed, it did in fact work. RevB was part of the problem. It also resolved the issues with the keyboard. So my original presumption of Basic / Game Rom / OS was incorrect. It is in fact Game Rom / RevC Basic / Rev4 OS.
Tomorrow, I will attempt to install a different game. I will be using HxD hex editor for this. Due to its many features.
Update 5: February 23rd Final Update for now.
So I tried installing Tetris by radosoft, this game is smaller then 4KB. So the three attempts, were to place it at the beginning, end, and flush end of the 4KB. None of these attempts worked. Take into account that the file was a xex extension. So probably doomed from the beginning.
Next attempt was with Star Raiders, .rom extension. This one also did not work. I acquired my roms with the .rom extension from Here. SR and Qix were both verified roms from cartridges. If you do a search, this is signified with a K under the Dump column. With no desire to mess around with SR any more I proceeded onward.
This time, I went for my goal and tried Qix. The actual game i've wanted to install from the beginning. Woo successes has been achieved. Its not the super nice 5200 port, but still good none the less. Pictures below.
Additional References:
How to install a game on the 1200xl, post 19 and 21.
Info on OS revisions. Additional info on OS revisions.
Info on chip identification.
Summary:
Order of roms (Game Rom 8KB / RevC Basic 8KB / Rev4 OS 16 KB) to be concatenated. Image must be 32.0 KB (32,768 bytes).)Success was only achieved with .rom extension game roms, but is not guaranteed. Nor was my testing extensive. The HxD hex editor was used to do most of the work. Eprom tms27c256 was programmed with a gq-4x. Rom extension images from cartridge dumps marked K in dump column are Here . Most of the Atari basic and os roms are Here.
Atari Age Thread
Atari Xegs (#1) Change the internal game
As some of you may know, the Xegs has Missile Command built in. Which activates when the keyboard isn't plugged in. I'm experimenting with changing this game to another 8KB game.
Unlike several other Atari 8bit computers. I'm making presumptions that the ic contains the OS (16KB), Basic (8KB), on the same eprom. As their are no independent ic identified as to the ic containing the basic kernel on the Xegs mobo. Assuming it holds the game rom. (Edit: Source found, it does in fact contain the game rom, basic, and os). It took several tries, experimenting with the order to concatenate the 3 roms. So far only the OS and Basic have had functionality restored. Sadly, no game as of yet. I've used both generic 27256 (nmos) and TMS27c256 (cmos) eproms.
Order of concatenated files, that allowed for Basic and Self Test to be booted.
RevB.rom Basic (8KB) short hand B
SpaceInvaders.rom (8KB) short hand si
Rev4.rom OS (16KB) short hand 4
Possible combinations to concatenate the roms.
4/B/SI Failed
4/SI/B N/A
B/SI/4 Basic and Self Test accessible, so far no game.
B/4/SI Failed
SI/4/B Failed
SI/B/4 N/A
I'm using the direct rom dumps, as anything with a xex, etc have headers for emulators. This size difference would surpass the maximum of 32KB (32,768 bytes) available to a 27256 eprom.
What will happen in the next portion of the experiment. I want to verify that the missile command is in fact on the same eprom. Through a process of elimination, a new file will be concatenate with B(8KB)/B(8KB)/4(16KB) and programmed onto a 27c256 (32KB). If this works and i'm able to access Basic, self test and missile command. More digging will be required to find the missile command rom's location on the mobo.
Alternatively, if missile command does not boot and the order of B/GameRom/4 is correct. I must surmise that my game rom files tested so far, are in fact bad dumps. Testing of the rom(s) in a emulator, will then be required prior to proceeding. If the roms pass via the emulator. A eprom will be programmed as B/Missile Command/4 bin file later and giving that a try. If that works, I will continue to proceed with say Qix.
Update 1: Still February 22nd
I burned an eprom with RB/RB/R4 (Basic RevB 8KB/ Basic RevB 8KB/ OS Rev4). Inserted into the xegs, and it booted directly to Basic. Then executed the self test. Using the Reset button to access the feature. It preformed Rom Ram and Visual Audio Test. Rom Ram Test, all showed green. 2 for the Rom, and 48 dots for ram. Last 16 are reserved for special programs, as noted on February 21st, Atari 65xe (Part 3), check Manual. As before, Visual and Audio Test worked flawlessly. No game rom was observed.
Update 2: Still February 22nd
Here is where it gets confusing. So I burned a RB / Missile Command / R4. Placed it in the socket. Keyboard is not plugged in. Boots up into basic. Reset allows Self Test as usual. Turn her off and plug in the keyboard. Proceed to turn her on and the unit boots into Missile Command. This throws me back. So I figure, perhaps my previous assertion about the order was in fact wrong. So I burn another eprom. 100% guessing the first two 8KB are interchangeable in the series of 8KB/8KB/16KB. Upon turning the system with Missile Command / RB / R4. A black screen comes up with either the keyboard plugged in or not.
My short hand again
Rev4 OS = 4
RevB Basic = B
SI= Space invaders (Rom was a bad dump)
MC = Missile Command (Seen Working on Xegs)
Status of Possible combinations to concatenate roms.
4/B/SI Failed
4/SI/B -N/A-
SI/4/B Failed
MC/B/4 Failed
B/4/SI Failed
B/SI/4 -Basic and Self Test accessible, so far no game.
B/MC/4 Basic, Self Test, and MC all work.
With the oddity of Missile command booting with the keyboard plugged in, and basic booting with it unplugged.
Next on my check list. Will be going back to the B/B/4 eprom. Observing its behavior with the keyboard. This is when I wish I had an oscilloscope. May try do up an eprom with RevC Basic. As a quick search found an article by digital press identifying RevC as the version of Basic used by XE units.
Next best thing is research to find out what controls the selection between Basic and Game rom. Assuming the keyboard normally performs a loop in the connector. I need to find a diagram for the xegs. Though in the meantime, I found a diagram that I will have to look at later. Looks like you could hook up a xegs keyboard to other 15p connectors on 130xe units.
Update 3: Still February 22nd
Just felt like relaxing outside of the work shop this evening. So I decided to continue my work on the laptop. Found the rom of C101687 online. Time to do some investigating, using a hex editor. As I do believe its human error at this point. So I loaded the C101687, RevC Basic, Rev4 OS and Missile Command into individual windows. Did a quick visual comparison of several lines of code that indicated the order in which it is concatenated; Missile Command / RevC Basic / Rev4 OS. Which is a order that has not worked for me. Though in previous attempts I did try to use RevB Basic. Even with the known working Missile Command rom.
Then I remembered HxD allowed file comparison under the analysis menu. Literally 2 bytes of information are different. That exist in the Missile Command portion of the code. I'm not a programmer. Nor am I pretending to be one. Only knowing enough to fool around with this editor and figure stuff like this out. Again, its half the fun.
Line 000011C0
C101687 original rom
BD 51 FB C9 3A B0 0A C9 30 90 06 E9 30 85 86 10
My concatenated rom
BD FE FE C9 3A B0 0A C9 30 90 06 E9 30 85 86 10
So tomorrow I will be burning my own concatenated rom. Testing it and see how it turns out. As all my previous concatenated files were using RevB basic. Not sure if this would have made any issues. Though, Id rather work on this before making modifications to hardware after doing more research.
On the plus side, this may also resolve the issue that I had created in previous attempts. With the Basic being first 8KB portion of the 32KB rom. Causing it to boot with no keyboard attached. Then Missile Command booting with the keyboard attached.
Update 4: Yeap, its still the 22nd. Quick Update
Decided I need to go back into the workshop. I fervently needed to know the burning question in my head. If those two bytes would be at fault for the issues i've been experiencing. That being very unlikely, as it's already been seen working.
On the other hand, was it the RevB Basic I had used, vs RevC Basic. The new concatenated file that minus those two bytes is identical to the original C101687. Indeed, it did in fact work. RevB was part of the problem. It also resolved the issues with the keyboard. So my original presumption of Basic / Game Rom / OS was incorrect. It is in fact Game Rom / RevC Basic / Rev4 OS.
Tomorrow, I will attempt to install a different game. I will be using HxD hex editor for this. Due to its many features.
Update 5: February 23rd Final Update for now.
So I tried installing Tetris by radosoft, this game is smaller then 4KB. So the three attempts, were to place it at the beginning, end, and flush end of the 4KB. None of these attempts worked. Take into account that the file was a xex extension. So probably doomed from the beginning.
Next attempt was with Star Raiders, .rom extension. This one also did not work. I acquired my roms with the .rom extension from Here. SR and Qix were both verified roms from cartridges. If you do a search, this is signified with a K under the Dump column. With no desire to mess around with SR any more I proceeded onward.
This time, I went for my goal and tried Qix. The actual game i've wanted to install from the beginning. Woo successes has been achieved. Its not the super nice 5200 port, but still good none the less. Pictures below.
Additional References:
How to install a game on the 1200xl, post 19 and 21.
Info on OS revisions. Additional info on OS revisions.
Info on chip identification.
Summary:
Order of roms (Game Rom 8KB / RevC Basic 8KB / Rev4 OS 16 KB) to be concatenated. Image must be 32.0 KB (32,768 bytes).)Success was only achieved with .rom extension game roms, but is not guaranteed. Nor was my testing extensive. The HxD hex editor was used to do most of the work. Eprom tms27c256 was programmed with a gq-4x. Rom extension images from cartridge dumps marked K in dump column are Here . Most of the Atari basic and os roms are Here.
Atari Age Thread