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  1. cy384

    Wombat (650, 800) board overclocking limitations

    thanks for the support guys, it's appreciated. I had a little time to experiment today: * under heavy CPU usage (raytracing for a long time), I think 46MHz is the max without locking up or crashing (48 and 50 are not very stable under load) * I've been experimenting with Ghidra to disassemble...
  2. cy384

    Wombat (650, 800) board overclocking limitations

    So I managed to boot with a large RAM disk with 3x128MB plus the 8MB onboard. The memory extension/control panel crashes with a bus error, so the procedure here is kinda funky, I want to note it for the future: * boot with 2x128MB and set the RAM disk to as large as possible * shut down, add...
  3. cy384

    Wombat (650, 800) board overclocking limitations

    yeah, I've been looking at his page here and forum thread here. It's very interesting to see it failing like this, I wonder if it's because something has some hard-coded memory location on the assumption that no 68k Mac will ever have more than 256-ish MB. Or if it's just a failure in the memory...
  4. cy384

    Wombat (650, 800) board overclocking limitations

    I'll admit I didn't test 45, just 44 and 46. Just added bbraun's large SIMM support (one line change in a part of the ROM I already disassembled), just got it going with a total of 264MB (128, 128, and 8 onboard). I'm a little concerned about how this actually works, I guess the 8MB gets...
  5. cy384

    Wombat (650, 800) board overclocking limitations

    I just got a 23MHz oscillator (seems like I'm collecting the full set, huh). It will consistently boot to 46MHz with no video problems (with my latest ROM, with only djmemc speed/config changes) but only with extensions disabled. Unfortunately, it seems like networking won't operate above...
  6. cy384

    Wombat (650, 800) board overclocking limitations

    There's some code in "DepVideoEqu.a" which I think is configuring the video hardware, and there's some stuff like "dafb40MHzConfigW" which seem frequency related and may solve the video problems, if I can figure out how to actually patch that part of the ROM. It seems like this may be one of...
  7. cy384

    Wombat (650, 800) board overclocking limitations

    I tried again a few more times without success, but it did run for a little while! I guess 48-ish MHz is the real limit of the hardware. It's clear that the video hardware, at least, is at its limit. So, here's some possibilities: * some other hardware config registers aren't set right for...
  8. cy384

    Wombat (650, 800) board overclocking limitations

    I was depressed about this, but on my lunch break decided to try booting again (excuse the giant pic, on my phone and can't resize)
  9. cy384

    Wombat (650, 800) board overclocking limitations

    Ok, I have some good news and some disappointing news. Good news: got the socket soldered on, the SIMM programmed, and it seems like my latest ROM hacks with "always 40MHz" settings works, and boots successfully with a 22MHz oscillator. Disappointing news: I immediately popped in a 25MHz...
  10. cy384

    Wombat (650, 800) board overclocking limitations

    This evening I desoldered the ROM socket holes for my mobo, as I have the connector and ROM SIMM coming in this week. There's another trick/technique that nobody has mentioned: solder doesn't stick to pencil lead (graphite). This wouldn't help for normal desoldering where there's a pin or...
  11. cy384

    Micrographic Images Megascreen 3 - SE PDS Video card

    I think the thread got lost, but I found a "MegaScreen for Macintosh SE" that looks much like yours. There is a working driver for system 6. @quorten has a page with some info and drivers: https://github.com/quorten/megascreen I couldn't get mine talking to any displays I have, curous to see...
  12. cy384

    Wombat (650, 800) board overclocking limitations

    that's basically what I thought when I saw it, I was randomly skimming the code for other reasons. it may be a lead on things to mess with if the djmemc changes aren't enough to improve the overclock. I'll note, as an aside, that the nubus interface has its own clock, so maybe if the onboard...
  13. cy384

    Wombat (650, 800) board overclocking limitations

    brief note on something to look at: the video driver for these machines checks the CPU speed, see DAFBDriver.a and search wombatspeed maybe there are other drivers that also check like this
  14. cy384

    Quadra 950 ROM Hack

    do you have a programmer? I've been trying to figure out the most convenient setup for experimenting, but I haven't seen anything great yet.
  15. cy384

    Quadra 950 ROM Hack

    You need a disassembler to turn the hex into instructions, but the problem is that the hex may be either data or instruction, so it needs a lot of manual work to disassemble a whole ROM into something fully useful. based on this, one can search for "7000 72FF 2448" and replace the "7000" with...
  16. cy384

    Wombat (650, 800) board overclocking limitations

    yes, I wrote a little script to calculate and insert a new checksum. (I just also checked with a deliberately incorrect checksum, it looks like BasiliskII will boot anyway, so maybe that's not a good test) Entirely disabling the checksum verification code is also doable, but I kinda like...
  17. cy384

    Wombat (650, 800) board overclocking limitations

    So I had some caffeine today (bad idea), and ended up writing some scripts to mess with ROMs. Since this is probably going to be a bunch of related little bits of stuff, I've made a new github repo for it (see the rom-hacking folder for details). A proper disassembly would be cool, but for now...
  18. cy384

    Wombat (650, 800) board overclocking limitations

    So in reading the code and wondering how to get the other config settings going, here's another twist * the changes in the source for speedbump are dated "9/26/93" * there's some more changes dated "12/7/93" * Centris 650 release date: February 10, 1993 * Quadra 650 release date: October 21...
  19. cy384

    Wombat (650, 800) board overclocking limitations

    all of the stuff it prints is read from the registers or reported by the OS, the "ideal for XX mhz" takes the number of cycles in the register and basically reverses the calculation described in the ROM comments (+/- rounding errors) there are like 6 different ways that the ROM seems to set the...
  20. cy384

    Wombat (650, 800) board overclocking limitations

    Did a little more work on ultra-wombat-hax-tool, code and the new binary are on github (or download from my site). It interprets the bits and nicely prints a little more info.
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