warerat

Should be a group of jumpers on the board near the floppy connector. Even a newer model 1.2MB 5.25" I have from the PC days has them-- they're labeled S0-S3 on my drive, and the jumper is on S0.

I have! I have a semi-working prototype right now (Almost Rice has seen it). It makes the 800 into a 576K XL machine (gives 32K to main memory, and full 512K to ramdisk), only uses four ICs. That frees up slot 3, and slot 3 already has the $D6XX select for an internal MyIDE. The RAM board requires a few extra wires to the ports 3 and 4 for the bank selects and extra RAM enable. Now it's just a matter of cleaning up my connections-- I have some intermittent failure somewhere on my protoboard that causes it to work sometimes and not others, but the design is complete. Booting SpartaDOS on the 800 is surreal, running RD.COM and getting a ramdisk is insane. 1025904[/snapback] Sounds cool, but I'd need 64k; 32k restricts you further it seems to me making the other upgrades less effective( or pointless in the case of the XL OS), might as well keep the 48k ram and just do an Axlon compatible memory upgrade for ramdisk. What does it matter if you have a ramdisk and MyIDE if you can only run 32k programs (which are fewer and older)? Am I misunderstnding you somehow? Isn't the whole point of having the XL OS so that you can have a full 64k of main memory and compatibility with all the 64k software?!? 1026127[/snapback] It is a 32K RAM board with extra XL banked memory in slot 2, leaving slot 3 free. This is used in conjunction with the 16K in slot 1-- there's your 48K. The additional 16K RAM is on the OS board, so it *is* a full 64K 800XL with extra memory. The point of this whole upgrade is to make an 800 run the newer programs, not take away any functionality. So: OS Board 16K RAM/ROM + Slot 1 16K RAM + Slot 2 32K RAM & extra = 64K main memory + extra RAM with an XL OS in an 800. With both boards in place my 800 is a 576K 130XE, sans switchable BASIC, self-test, and HELP key.

I have! I have a semi-working prototype right now (Almost Rice has seen it). It makes the 800 into a 576K XL machine (gives 32K to main memory, and full 512K to ramdisk), only uses four ICs. That frees up slot 3, and slot 3 already has the $D6XX select for an internal MyIDE. The RAM board requires a few extra wires to the ports 3 and 4 for the bank selects and extra RAM enable. Now it's just a matter of cleaning up my connections-- I have some intermittent failure somewhere on my protoboard that causes it to work sometimes and not others, but the design is complete. Booting SpartaDOS on the 800 is surreal, running RD.COM and getting a ramdisk is insane.

You can disable the ROM by dropping RD4 and RD5 on the cart slot. Grounding RD4 would show the ram from $8000-$9FFF and RD5 would be $A000-$BFFF. Some bank switched cartridges latch them through /CCTL so you can turn off the ROM. The XL/XE has the self-test ROM from $5000-$57FF selectable via PB7.

Can you toss one of those 130XE's my way? Mine just died 999256[/snapback] I'll take your broken one off your hands!

I thought that was the case and have always wondered why it seemed little was made for it compared to the 800xl. 1003376[/snapback] Probably because even though the 800 had slots, there was no way to access the FULL bus (easily) like the PBI/ECI on the XL/XE line. It is VERY conceivable for one to have PBI devices on the 800-- it is after all, an Atari 8-bit. You'd need to run a line from the $D1XX select on the personality module (which is unused) to the testing slot. Also would need some logic changes in the MMU to allow the FP ROM to be deselected and a few lines to deal with that. Other than the physical interface (and the OS ROM, which has been solved), all the signals are there are on the back connector.

That's great for Apple and Commodore owners but I don't see anywhere on the page that it works with any Atari. Allan 1003017[/snapback] I think I can use the 44-pin VIC-20 connector for my 800 hacks!

I guess the 800 with an XL OS wouldn't be complete without extended memory. This is an "80K" memory module, with the standard 16K as the main bank, and a single 64K SRAM for the extended bank (got to love hi-density SRAM, makes me want to convert all the 800's RAM to SRAM to get rid of those bi-polar supply power hungry 4116 DRAMs!). Three connections to the joystick port for this one. One for extended bank select, and two for the bank numbers. This more or less makes the 800 look like a 130XE. I got a slight timing problem with the memory to work out, but I can switch between DRAM/SRAM and get different banks. Work in progress... Couldn't you call this a "real" 800XE?

Hi everyone. Thanks for the interest in this, didn't know there was still an interest in the 800. I'm cleaning up the design (minimizing pin count on GAL) and will write up what needs to be done. Anyone know of a good PCB service? I'd like to make a real PCB and make a small run of the new boards.

I like the way you think. I was thinking about putting a simm into my 800xl or XEGS, but this would be much more interesting. 997284[/snapback] I am in the Clear Lake area.

Well after a little bit of work, I'm pleased to report that I have successfully converted my Atari 800 into an 800XL, sans switchable BASIC and self-test. Nothing makes me beam with pride more as my old friend boots up SpartaDOS 3.2d in Ultraspeed. Time to toss my 130XE's away! To do this only required a change to the 10K OS personality module. I added the XL OS, a SRAM for the RAM-under-ROM, and a custom 800 MMU GAL for the additional decoding. I now have a true 64K Atari 800 with switchable RAM. It only requires one external connection to PB0 on joystick port 3 for the OS RAM/ROM switch to make it software controlled like the XL/XE. The wire hanging out on the right is what is connected to PB0. Phase two will be to get a switchable BASIC, but I will require some additional jumpers to the last memory slot to do this, as I have some spare pins on the GAL to implement it. I'm ready to hold down OPTION! I'd like to make a real PCB for this, as this rat's nest of wiring is driving me crazy. The old dinosaur just got a new lease in life! Take this mod, coupled with SIMM mod in one of the RAM slots and plugged into port 4, and the venerable Atari 800 can be made to look like an XL/XE!

ALMOST there! The SRAM is wired and addressable. I have a joystick cable plugged into port 3 and have "up" (PB0) jumped to the personality board. I can almost boot SpartaDOS 3.2! It now gets past the "Error: Not XL/XE computer" and begins to load in ultraspeed, but it glitches and displays garbage after a few sectors. I'll double check my wiring and go back to the logic analyzer if I can't see anything obvious.. I can put $FE in $D301 (disable OS) and the machine crashes, so that is a good sign. SysInfo shows it as an XL/XE computer w/ 64K RAM in DOS 2.5. This is surreal. I loaded the self test from disk into $5000 and it runs. So the bottom line is: *YES*, an Atari 800 can be modified to work like an XL/XE and I am 90% there. In fact, if I was willing to get more motherboard signals to the OS board, I could even use an Atari CO60618 MMU. I just wanted it to be as self contained as possible and require minimum hacking so you could switch back and forth if you wanted to. With an extended RAM board in the middle slot, I think it is very possible to make it look like a 130XE.

Well, I'm able to run the 800 with the XL OS now. It can boot up completely in cartridges or with BASIC. Had to do a slight mod to the NMI reset vector code as the 800 has a software reset via NMI. So the reset key works now. Now all I have to do is wire up the SRAM, connect it to the joystick port, and boot up SpartaDOS 3.2.... And I'll have a true 64K 800! The pinout I have for the 130XE keyboard is: 1 +5V 2 LED power 3 GND 4 IN 6 5 OUT 3 6 OUT 5 7 OUT 7 8 IN 2 9 IN 7 10 IN 5 11 IN 1 12 OUT 6 13 OUT 1 14 OUT 4 15 OUT 2 16 IN 3 17 IN 0 18 OUT 0 19 IN 4 20 RSC 21 START 22 SELECT 23 OPTION 24 RESET

Hate to see another 800 hacked up... At least it's still an Atari and not as crazy as this: http://www.mini-itx.com/projects/atari800/ If anyone is interested, I'm modifying a personality module to have the XL OS and the RAM under the ROM. I've got the 16K EPROM retrofitted with the XL OS, and it almost works all the way. I can play Star Raiders with an XL OS on my 800 . My goal was to turn my 800 into at least a 64K 800XL with *minimum* hacking by just switching out the ROM module and adding a joystick dongle. There is 16K RAM under the ROM via a 62256 SRAM-- well 14K, the hardware chips can't be mapped out. I was going make an external connector in the back and run it to the joystick port to get PB0. I have my equations worked out and a GAL programmed to do this right now. Initially the switchable self-test and BASIC won't be available yet, but are indeed possible, just may need to jumper some signals between the slots externally. Damn it, why didn't Atari give me A13 & A14 on the OS board!?! It's getting stuck somewhere in the initialization sequence and I have it on my logic analyzer trying to figure out why it's dying (nothing like pressing the trigger on joystick 4 to simulate RD5 for a cartridge insertion!). I think it's do-able. Attached is a picture of the module--consider it a 16K Personality Board without the RAM yet. It works as an Omnimon board too now. As I'm not able to see a blue screen yet, I can't declare victory on the ROM side...

The stock 16K board is just inverting /RAS to generate /CAS. If you look at the output from the 'LS10, /RAS is the active-low output. Past the RL delay, the third mux in the second 'LS158 has bus A tied high, and bus B tied low. /RAS is tied to the data select, and as /RAS is active low (bus A), the output will be high (inverse). So they're just using one of the muxes as an inverter. How will you be doing the bank select? The Axlon method?

If you're using the OS-B 10K binary image, you must offset the start of data. That way you're starting at $D800 which is where the 800 OS starts, as $C000-$D7FF are unused (EPROM absolute addresses $0000-$17FF). So in your EPROM burning software, make sure to load the binary file at offset $1800. I've done this on my 130XE. Use a 27128.

Anyone know where to get card-edge connectors to plug into the cartridge slot and PBI slot? (maybe even blank PCBs that take EPROMs). What I'm looking to do is to interface some home-brew devices to my 130XE. Thanks!