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MEtalGuy66

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MEtalGuy66 last won the day on October 17 2009

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About MEtalGuy66

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    River Patroller
  • Birthday 10/19/1973

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    If it aint broke, fix it anyway!
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    Male
  • Location
    Houston, TX, USA
  • Interests
    ATARI XL/XE hardware repair, ICD Multi I/O reproduction/development, SpartaDOS, MAC/65, BASIC XE, ATARI TELNET BBSes and related hardware, AMIGA 1000/500/500+, preservation of the 5.25" floppy as a standard for 8-bit computers.

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  1. Wow. None of the old schoolers care to chime in here? Anywayze, I have a few things further to add. I noticed that StGuild said in an earlier post: Is it a Toggle-switch? I assumed it was a momentary push-button. If it is in fact a toggle switch, then it has something to do with the way the PIA bits are used to address the expansion. One popular "switch" of this sort that would be connected in such an upgrade was to change between "compyshop and rambo XL" similar banking schemes. Another was a "switch" to give back 1 bit of PIA control, reducing extended ram to 192k, but allowing separate ANTIC and CPU access to the currently selected extended bank. This is sometimes called "100% 130xe compatability mode". At any rate, what you should do is download SatanTronic's XRAM prorgam and see which banks show up with various switch positions. This Demo, known as VBLITZ or VIDEO BLITZ used to be the definitive test of 130XE ANTIC Extended Video Mode. (You have to unarc it first) Lastly, here's a picture of a REAL 1meg upgrade, like we used to do back in the 80s.. Looks like it might have been done by the same guy who did your 320k. Notice he has not only replaced the extended bank with 256k DRAMs, but he's piggybacked an additional 3 banks of chips and hand-wired the address lines as necessary. I have forgotten what the various switches do, but you can bet they have to do with banking, compatability, etc. To get enough PIA bits for 1meg, you have to give up Internal BASIC, SELF TEST, Extended video, etc. Scott Petersen was a hardware guy back in the 80s who came up with these upgrades and published them in step-by-step articles which would be distributed as text files on BBS systems. Most Atari user groups had a "hardware guy" that could install these types of mods for people. Petersen did the original 320k article, followed by a 576k, and finally a 1088k... Somewhere, I have all of the original text files, but I'm sure they are available in many places on the web. Oh well. Just thought I'd reminisce a bit, about the way we USED to do things, since STGuild brought it up.
  2. That's not a 1meg XE.. That's a 320k.. How do I know? Only 2 additional PIA bits are used by that expansion (only 2 wires going to the PIA chip). The 130xe used 2bits for extended ram in stock configuration.. Adding 2 more gives you 16 (2^4) banks of 16k.. 16 x 16 = 256... So 64k base ram plus 256k extended.. Thats 320k.. Very popular upgrade.. There's also the fact that there's only 1 bank of (256k)DRAM chips in the extended bank. They did make 1meg DRAMs but no one used them for homebrew atari 8 bit ram expansions because they require additional wiring to connect, and even more additional circuitry for refresh because ANTIC will not refresh that many address bits of DRAM by itself.. What's under the black tape, you ask? Probably a 74HC86.. You see the momentary push button on the back of the case? Hold that button and hit reset to cold-reset the machine without wiping out the contents of the extended ram.. You have to boot back up and use a special ramdisk handler to reconfigure the ramdisk without initializing it, but you can cold boot the machine and still have your data in ram.. Anywayze.. What you have there is a "Scott Petersen 320k upgrade", with a "Bob Wooley freezer switch" mod added.. It looks fine to me.. make sure there's no broken wires, and no exposed wires touching anything metal.. Put it back together and enjoy.. There are plenty of demos that use the extra ram, and you can use it as a 256k ramdisk in both SpartaDOS X, and disk based versions of SpartaDOS.. If I was you I'd either (a) leave it alone and enjoy your 320k XE... Or (b) Buy an "Ultimate 1 Meg" Expansion from Lotharek and find a competant hardware guy to put it in for you. Regards, Ken Jones Metalguy66
  3. _The_Doctor__, wtf is the "almost rice" version? You really should keep your mouth shut on topics you know nothing about. The "blue" wires on the back of the MIOs had several functions and it doesn't matter which side of the PCB they were on. I've seen ICD put them on either side.. top or bottom. One was the deletion of the 12v power circuit from the design which happened fairly early on in the production history of MIOs, so most of them were built this way. The second was a propagation delay for the highest order DRAM address line. It used a few spare gates in one of the ICs to add ~10-20ns of delay to that line so it would more closely line up with the others in the DRAM access timing. Almost Rice (Tuon Ho,) is a personal friend of mine.. I assure you he had nothing to do with MIO firmware development. WareRat is the man responsible.. You should get your shit straight before flapping your jaw. Somewhere, I've got 1.2 and 1.3 ICD MIO EPROM binaries and partial source code. I might get persuaded to dig them up if someone's interested.. But not tonight.
  4. MEtalGuy66

    MEtalGuy66

  5. One PCB, three possible models depending on population/assembly. Makes ALOT more sense than IDC cables anus-rigged into chip sockets.. 90% of needed signals for either/both devices are available at ANTIC socket. It's a "no brainer"..
  6. Awesome. I need about 20 of those. I have another great idea for you.. Merge VBXE and ULTIMATE 1MEG into a single product, and get rid of the stupid "tape-worm" cables..
  7. What we need is an Apple IIgs emulator for the Rapidus+VBXE..
  8. DRAMs were expensive. Possibly he was waiting till he could afford them, or waiting to get the ballz to desolder 8 chips..
  9. Offer the movers a free case of beer if everything arrives perfectly sound with no incidents.
  10. Yeah, 2600 star raiders is not the benchmark, but the exception. Sorry you don't like the 5200 control scheme, but the 8-bit Home computer version is the original version and concept of the game. The 5200 version is even better because analog joysticks allow for proportional steering on two axis within the 3D spaceflight simulation environment. Crappy control buttons or not, this is clearly the BEST version of Star Raiders out there.
  11. My life is a mess.. I don't know if/when I'll ever get time to work on MIOs again. Maybe I'll give everything to WareRat and let him continue.. Truthfully, he was the real brains behind it all anywayze..
  12. Looks great, man. Thanks for sharing.
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