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redman

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Everything posted by redman

  1. Hello all, I just finished putting a 27C801 eprom into an 800XL to replace the Basic rom. The eprom holds 128 8K images. I put in just about every 8K image that I could find knowing that some of them wouldn't work. About 80 of them work. Some of them were probably for the 2600 and some may need conversion. I'll post a list soon with the names of games that worked and also those that didn't. I mounted 7 switches on the top right of the computer for rom selection. It turned out to be a good project because my grand niece can't get enough of Pacman & Frogger. Redman
  2. Well it's not on the workbench anymore but I just finished stuffing an 800XL, a Rana 1000 floppy and a few mods into a case from a broken Kaypro 4. The mobo from the Kaypro was bad and I had no luck fixing it, so I decided to use the case for a project. I had the guts from a brand new 9 inch amber composite monitor in the closet. It bolted right up to the Kaypro case. I used an 800XL mobo with the Super Video 2.1 mods installed. If you haven't done this mod, you should. The picture is fantastic. The mobo is mounted in a similar fashion to the original, horizontally across the top. An Atari 1050 wouldn't fit in the case but I trimmed up a Rana 1000 and mounted it on it's side. I installed a Warp+ OS 32-in-1 Module so the thing would have all kinds of compatibility. I replaced the BASIC rom with a 27C1001 eprom loaded with Atari BASIC rev.C, Assember Editor, and 14 games. I switched the top address line with a toggle switch and called in Bank Select and switched the other address lines with a BCD switch removed from an old SCSI device. Each bank has 8 selections. That worked out nice. I built in an SIO2PC circuit and mounted a 25 pin female connec tor on the back because I have a box of them. I added the Freezer reset mod and mounted the switch on the front so you can change roms and reset without turning off the power. I mounted the Atari keyboard inside the Kaypro keyboard case and once again used 25 pin female connectors so a serial cable can be used to hook up the keyboard. It's nice to be able to lean back in a chair with the keyboard on your lap. There's a hole in the top of the case for cartridge access and an SIO connector mounted on back so I still have all the original Atari connectivity options. The color video including separate video (S-Video) and audio are available at the original DIN connector on the back. I added a speaker and an audio amplifier internally so the unit is fully functional as a standalone with the exception of the monochrome video. I wish that I had a good 9 inch color monitor to use. I fed the luma video output to the composite input of the monitor and the video is extremely sharp. I had a small switching power supply that had 12V 1 amp and 5V 1.5 amp outputs. The monitor power is switchable so if you use an external device it can be turned off. I used the original power supply from the Rana 1000 and strapped it to the bottom of the case. I think that this was the nicest project that I ever did but I did run into some problems. The video looked great on the bench but when I put the mobo in the case, all kinds of distortion occurred. The problem was that the video lines had to be moved to the back away from the monitor. The floppy also worked on the bench and quit in the case. After more than a few swear words, I mounted a thin metal shield vertically between the monitor and the floppy and that cured the problem. I have attached some pictures. kaypromod.zip
  3. Congrats! It disables itself... if you put that EPROM on a cartridge board, it'd work. The very first thing River Raid does when it gets control is that it writes zeroes to all the hardware registers... including PORTB, which controls the ROMs on an XL/XE (it's joystick ports 3/4 on an 800)... which isn't a problem when a cartridge does it (can't enable/disable a real cartridge, so the code keeps running). When you install the same code as internal BASIC replacement, it does the same write to PORTB, and the MMU obligingly disables the ROM... whoops! In an emulator, the same thing happens if you tell the emulator to load the BASIC ROM image from "River Raid.rom"... the offending instruction is at $A01B, a STA $D300,Y where Y contains 1. Since River Raid is a "diagnostic" cart, it normally gets control very early in the boot process, which it why it initializes the hardware itself... but when running as a BASIC replacement, the OS has already initialized the hardware, so there's no real need for the River Raid code to do it again... I patched the ROM image and replaced the writes to the PIA with NOPs. The patched image works correctly as "basic.rom" in the atari800 emulator, but I didn't burn to EPROM and test on real hardware (still haven't done the hardware mod to allow me to use 28-pin EPROMs for BASIC). Try it: river_raid_basic_replacement.zip Let me know if it doesn't work, I'll take another crack at it... P.S. I should mention that Star Raiders has the same problem. Someone posted a patched binary to this forum a while back and explained why it was needed, which is how I knew what to look for here. Works perfectly. I didn't go all the way down the river but it looks good. Thanks again. I really like this game and wanted to have it in the 16 rom image eprom.
  4. Congrats! It disables itself... if you put that EPROM on a cartridge board, it'd work. The very first thing River Raid does when it gets control is that it writes zeroes to all the hardware registers... including PORTB, which controls the ROMs on an XL/XE (it's joystick ports 3/4 on an 800)... which isn't a problem when a cartridge does it (can't enable/disable a real cartridge, so the code keeps running). When you install the same code as internal BASIC replacement, it does the same write to PORTB, and the MMU obligingly disables the ROM... whoops! In an emulator, the same thing happens if you tell the emulator to load the BASIC ROM image from "River Raid.rom"... the offending instruction is at $A01B, a STA $D300,Y where Y contains 1. Since River Raid is a "diagnostic" cart, it normally gets control very early in the boot process, which it why it initializes the hardware itself... but when running as a BASIC replacement, the OS has already initialized the hardware, so there's no real need for the River Raid code to do it again... I patched the ROM image and replaced the writes to the PIA with NOPs. The patched image works correctly as "basic.rom" in the atari800 emulator, but I didn't burn to EPROM and test on real hardware (still haven't done the hardware mod to allow me to use 28-pin EPROMs for BASIC). Try it: river_raid_basic_replacement.zip Let me know if it doesn't work, I'll take another crack at it... P.S. I should mention that Star Raiders has the same problem. Someone posted a patched binary to this forum a while back and explained why it was needed, which is how I knew what to look for here. That's funny because the first 27C010 that I burned had Star Raiders and it didn't work either so I took it out because it's not one of my favorite games. Now this makes sense. I'll try your patched version ASAP. Thanks a lot.
  5. I got a 27C010 128x8K eprom working as a replacement for the BASIC rom on an 800XL. I used a s.p.s.t. switch to turn address line 16 on & off and this selects 2 blocks of 8 8K rom images. Lines 13, 14, & 15 are connected to the 1,2,4 terminals on a bcd switch removed from an 8bit SCSI device. The common switch connection is connected to GND. Rom selection works perfectly. The only problem that I have is that River Raid doesn't work. I got the cart image from 2 different sources and they match. I burned 2 different eproms with R.R. in a different spot on the eprom and the 15 other rom images work but not R.R. Has anyone ever burned R.R. on an eprom and had it work? I know that the real cart works with an 800XL so why doesn't it run from an eprom? This has been a great project and I'll be adding big eproms to all my Atari 8bits.
  6. Yep, that's the stuff. I have a couple of nice 28-pin sockets like that. They look like the legs are too stiff to bend though... will try it. I actually have an old ISA board with 5 or 6 of the nice sockets on it, but so far no luck desoldering them (the pins get too hot, and melt the plastic carrier). That'd be a lot nicer than DIP switches... where were you thinking of mounting them? Looks like the side of the case, behind the joystick ports, might have room if the switches are small... otherwise I guess they have to go on the back, next to the SIO port. Means you can't see the numbers on the switches without moving the Atari to look at the back, but also means no visible holes in the case when looking at the front of the computer. I haven't looked into parts placement yet. I want to make sure that this will work before I start drilling holes. I usually drill holes first and think later. I've screwed up a lot project cases that way. This time I'm going to slow down and try to make it look good. You're right about not seeing the switches on the back. That would make it very hard to use.
  7. I think bending them out will not work, the pins are so rigid they will just snap off. On the 'adapter-socket' I'd just cut off the narrow lower section of the pins that are not supposed to make contact with the original socket. The wider section just below the plastic carrier then leaves a perfect place to solder the rerouted wires to. Remember to measure with a multimeter afterwards to be sure the snipped pins do not make unwanted contact, and you should be allright. As you already observed, desoldering such a socket will give you a helluva job. I've never succeeded desoldering one intact. It looks to me, that the pins are such a tight fit into the PCB that, especially with through plated holes, the capillary of the solder will prevent them from loosening enough to get the socket out in one piece. re-atari Maybe something like this might work. I remember many years ago seeing a bunch of soldering iron attachments similar to this idea. http://www.geocities.com/BourbonStreet/3220/PCB_remov.html If I can find something that lines up with dip pins, I'm going to give this a try.
  8. It'll be a while before I get a chance to work on this... I've got a dead 130XE to fix first, and some non-Atari-related stuff. Replacing BASIC and the OS with one 27512 each would give 8 cart ROMs (3 select bits) and 4 OS ROMs (2 bits), can you think of a good way to select 5 bits other than DIP switches? I was thinking of using 2 BCD switches that I took off old SCSI devices. One for the OS and the other for the 8K roms. These have 4 leads that switch the common lead with the 1, 2, and 4 leads in a binary fashion. When 0 is selected there's no connections. When 3 is showing, the common is connected to the 1 and the 2 leads. Looks like this will work to me.
  9. I think I understand how to do it... Most of the pins on the 24-pin ROM match the positions on the 28-pin, so you only have to bend up a few pins in the new socket, and solder a couple of jumpers to those pins, then plug new socket in the old one, and new EPROM into the new socket... is this about right? If I'm going to do this, I'll probably use a 27256 or 27512 with some DIP switches or something, so I can have BASIC plus 3 or 7 more 8K ROMs. ASM/ED is a good one, so is the patched Star Raiders that a8isa1 put in his 800XL in place of BASIC... too bad Montezuma's Revenge isn't an 8K ROM, would love to have that built in. I really like the idea of having 7 more 8K roms built in to an 800XL. Please post all the specifics when this gets worked out. I've got a few 27C512's just looking for something to do.
  10. I have an 800XL with the RamRodXL board in it with OSNXL rom as one of the OS'. I can dump it this evening, if you want, as long as there are no objections from anyone. I really would like to see the dump of your eprom. I have 2 OmnimonXL images that differ by 2 bytes. If yours matches one of them, then that's the one I should use.
  11. I thought OSNXL was the OS that contained Omnimon. I wasn't sure if they were separate OS's or not. If they are, then I already have what I need.
  12. Hello all, Does anyone have the 16K rom image for the OSNXL upgrade? I can't find it anywhere on the net. I want to switch between 4 different OS's on an Atari 800XL and I would like to use (1) the original rom, (2) fix xl, (3) Omnimon, and (4) OSNXL. I'm going to burn them all into a 27C512 eprom and use a switch from an old SCSI hard drive to select the OS's. TIA. Ralph
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