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cbmeeks

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  1. cbmeeks

    68K (no Mac) Designs OK?

    Sega should have done what Atari did and just add up all the bits. The 68K with it's 32-bit registers plus the 16-bit address bus of the Z80. So the Genesis is a 48-bit system. LMAO. At least they had Blast Processing.
  2. cbmeeks

    68K (no Mac) Designs OK?

    Yeah, I think the 68000 and Z80's (for sound) are some of the most popular arcade processors from the 80's/90's.
  3. cbmeeks

    68K (no Mac) Designs OK?

    Oh yeah, huge fan of the Parallax forums. Yeah, I've heard of the MiSTer project. I don't want to use FPGA for the CPU. At least not at first. I will be using FPGA (and/or CPLD) for glue and video but not the CPU. Unfortunately, the project is on temporary hold as we just bought a new house! We are moving first week of September so my entire lab is in boxes right now. lol But I will keep everyone posted.
  4. cbmeeks

    68K (no Mac) Designs OK?

    I haven't decided if the CPU and framebuffer will share RAM. My initial thought is that they would. I don't really want to get into anything like cycle stealing/stretching or anything like that. My intent is to upgrade this machine to '020/030 one day and that method (like the original Mac) is less relevant on those machines. Especially when you start getting into SVGA resolutions/colors. The 10ns SRAM (16-bit) was surprisingly cheap so that's why I wanted to use those. And I figured 10ns wouldn't be any kind of bottleneck for anything I could every dream to design. But for prototyping with my wire wrap board, I will use the "slow" 55ns SRAM that I have that is in a DIP package.
  5. cbmeeks

    68K (no Mac) Designs OK?

    Small update... This weekend was unproductive. I had FOUR large deployments (for my real job) that took up most of my weekend. I did manage to solder the small QFP-64 68SEC000 to a breakout board. This breakout board will next get 64 wire-wrap pins soldered to it so that I can use it. Next after that is free-running it. Someone asked what OS. Well, at first, I *might* try uLinux just to get it running. But my goal is to develop my own OS. But that is a tall order. Either way, I will keep people posted. Thanks.
  6. cbmeeks

    68K (no Mac) Designs OK?

    Thanks everyone for the interest. I don't have a blog yet. But I really should start one. I really like the format that BMOW does with his projects. I might follow something similar. I'll either post my progress here (if no one objects) or just post a link to my eventual blog. In the meantime, I gathered up parts that I already have on-hand. My dream is to design a "Mac like" computer that would fit between the Mac 512K and Amiga 500. Closer to the Mac because the Amiga had advanced chips for it's day and I'm a HDL newbie. I will be wire-wrapping my first prototype starting this weekend. The CPU of choice is a 68SEC000. I have bought a TQFP-64 to DIP converter so I got some soldering to do. The final design will likely use a "largish" FPGA and maybe some smaller CPLD's. I don't want to go insane on the FPGA choice. Mainly because my eyesight restricts me to soldering TQFP-100 to MAYBE -144 packages. I have no interest in BGA. So, what do I actually have right now? Almost everything. However, they are a mixture of small boards, slower parts, etc. So not the final specs. For example, I will be using two SRAM chips for 16 bit memory that run 55ns. BUT, my final design will incorporate 16-bit SRAM at 8-10ns with 1 MiB minimum. I thought about getting DRAM chips because they are very cheap and 16 MiB would cost almost nothing. But, I don't want the extra hassle of DRAM refreshes and column/row logic. Plus, no affordable computer in 1984 - 1986 had 16 MiB anyway. 1-2 MiB for my final design sounds good and the 16-bit SRAM chips are not that expensive. On my CPU adapter, I have a small bag of wire-wrap pins that I will have to painstakingly solder one by one so that the adapter board can be used with wire wrap. Not to mention the small SMD CPU itself. Anyway, my parts so far are (for prototype): 68SEC000 CPU (with adapter) 512 KiB SRAM 55ns x 2 (used for odd/even) memory. 1 MiB total RAM. 128 KiB ROM 70ns NOR flash x 2 (used for odd/even) memory. 256 KiB total ROM. DUART Serial (2 ports) via NXP 28L92. ATF1504 CPLD (32 I/O) ATF1508 CPLD (64 I/O) - 7.5ns TinyFPGA A2 (~21 I/O) TingyFPGA BX (~41 I/O) Parallax Propeller MCU (8 cores, 32 I/O). Possibly used for audio (has great SID emulation) and/or general I/O for keyboard/mouse, SD, etc. Eventual specs for final design: 1-2 MiB RAM 256 KiB ROM SD card running FAT16 USB mouse/KB (MAYBE PS/2 if USB proves to be a headache). 640 x 480 VGA. I don't want SVGA, massive sprites, etc. I'm leaning more towards a simple frame buffer with possibly hardware blitter. For colors, I'd like to shoot for at least 256 (8-bit). I'm undecided if I want to force a static display (like the original Macs) or allow a more dynamic display like the Amiga (and later Macs). Sound. (duh..lol). SID emulation sounds good...but I probably won't use it. If you have memory, then audio buffers and DAC's sound so much better. Just compare the Amiga against the C64. The IIgs should be noted because of the massive number of channels...but still, sampled audio will probably be the way to go. Right now, most things are up in the air. More than likely, I will use the ATF1508 CPLD as a simple VGA controller and MMU. Mainly because it has the most pins. But I'm sure I will find something to do with those other PLD devices. If/When I finish my final design, I hope to have a smallish 4 layer board made. Which I will make available. If this is successful...if I love working on it after all of that....and people still want it....I might look into a second revision where the 68K is handled within an FPGA. Not true "retro", but much easier to sell and source. Any questions, just ask... Wish me luck!! PS, I still haven't thought of a name yet. I want something catchy but not cheesy. One thing I like about "Macintosh" is that it sounds good...looks good...and can be shortened to "Mac". Plus, it falls inline with "Apple". It would be hard to beat that.
  7. I'm sorry if I am way OT here. Last year, I designed a 65C02 computer and had some boards made. It worked very well and I was very happy. My next move was to design his 16-bit big brother using a 65C816. Seemed like a logical choice (still is, really). However, there was something pulling me towards the 68K. Mainly because I was a hard-core Amiga 500 user in the day. And, about 20 years ago, I started collecting classic Macs (I have several 68K series Macs). So I decided to byte the bullet (notice a play on words there) and design my first 68K based computer. It is heavily inspired on the original 128K Mac. But here's my issue...I need a place to bounce questions around and get advice on my design. I don't see many 68K forums online that aren't focused on a platform like the Mac or Amiga. My computer will be neither of them (but pull inspiration from them both in some areas). Am I in the right place? Or, is there somewhere else I should visit? Thanks!
  8. cbmeeks

    New Favorite, Mac 512K

    Holy crap...I forgot I have one of those Apple II 3.5" drives! I got it with my IIgs years ago. So, is it easier to transfer disk images over to it than 400K disks? Your blog is looking good. Do you plan on doing any posts about how to transfer images over to those disks? My primary PC is a Windows 10 machine. I also have a bunch of disks for the Amiga. I wonder if I could take a couple of them and format them for the Mac 512K?
  9. cbmeeks

    New Favorite, Mac 512K

    Yeah, I may be interested. I will send you a PM. Thanks!
  10. cbmeeks

    New Favorite, Mac 512K

    I've tried 15 times to upload more pics but all I get is an error message. Even pictures much smaller than the ones that worked. Not sure what that's about. https://www.dropbox.com/s/72u5g2aa1b64lab/Photo Dec 08%2C 2 14 01 PM.jpg?dl=0
  11. cbmeeks

    New Favorite, Mac 512K

    Some pictures of my new setup.... Half of the pictures would not upload for some stupid reason.
  12. cbmeeks

    Top screws SE30.. rounded out?

    Spiders are smarter than other insects. They like to "think different". What I hate finding in old computers are blood stains and rat turds. lol (yes, found both).
  13. cbmeeks

    New Favorite, Mac 512K

    So I just bought a (new to me) Macintosh 512K for $60 (USD). It came with the 512K (dur), keyboard (original), mouse (IIc mouse) and 400K external floppy drive. Oh, and a non-Apple bag to carry it all in. The computer has a small crack in the case on the top-right but I think I can eventually fix that or even replace it. It's also VERY yellowed so I got some retro-brighting to do. I will post some pictures later. The first thing I do is power it on. The seller showed a picture of it working. I don't have any software for it so all I got is the disk with a flashing ? on it. Which is a great sign! The startup tone was great too. The screen is superb. I cannot believe how great it actually looks. In fact, it's so bright that I have to turn DOWN the brightness to a comfortable level. The next thing I do is open it all up to see what damage it has. There is a SMALL amount of battery corrosion on the terminal leads. But it's so minimal I think I can literally put vinegar on it and scrape it off. When I opened the case, I was amazed how clean it was! Other than a little dust, there is NOTHING wrong with it. Almost mint. As you know, there are only three electrolytic capacitors on there. I will be replacing those soon. But they show no signs of leakage. I still cannot believe this board is all THT. Oh, even the ports on the board (DE-9, etc.) are super clean with no rust. I swear this board looks new. On to the analog board. Again, aside a little dust it's pristine. I will certainly want to re-cap it. I should start on that after Christmas. None of the caps look to be bulging. But I'm going to replace them anyway. So, as you can see, I'm very excited about this find. I think with some hard work I can make this computer almost new and mint with a few dings here and there (just like me...lol). Now, I have a few questions. 1) I attempted to remove the annode wire (I think that's what it's called) from the CRT. I made sure to properly discharge it first by connecting a long screwdriver to the ground wire of the CRT and slowly sliding it under the suction cup. I never heard any kind of pop. But I'm 100% sure I touched the metal under it. The problem is that I couldn't get it to come off. I didn't want to pry very hard but that wire seems to be bolted on tight or something. Is there a safe way to pry that thing off without cracking the tube? I've pulled them off on other Macs before. Not sure why this one has a death grip like it does. BTW, the suction cup is black and not red/maroon like someone mentioned in a previous thread. I thought they were all red/maroon too until I saw this one. 2) I'm pretty sure I have an 800K floppy as a spare. I have a super drive on a non-working SE/30 that I might be talked into using on this computer. But the fact of the matter is, 400K is going to be a problem. HOWEVER, since I have literally 0 disks/programs for this, is it possible to just buy some 400K software somewhere and use it? I just want to play a few games, mess with a few music programs and type a few letters. Nothing major. And since I have the external drive (also 400K) maybe the disk swapping won't be that hard. What are your suggestions? Do I need to upgrade the ROM if I use >400K drives? If I upgrade that drive, seems then that the external drive would be worthless. 3) Are there any recapping kits for the analog board on this computer? So that I don't have to manually trace down each size? Thanks!!!!!
  14. cbmeeks

    Apple Mouse IIc on Mac?

    I confirmed that you were correct! It indeed worked on my new Mac 512K. Thanks
  15. cbmeeks

    Apple Mouse IIc on Mac?

    Will the Apple Mouse IIc work on a Mac 512K without any adapters or conversions? I finally have one and I may swap it out between my IIc computer and my new 512K. Thanks!
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