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Yellowstone 2.2 First Look

Yellowstone version 2.2 is up and running! If you don’t remember what’s changed in v2.2, well… that makes two of us. Luckily we can both go read this August 20 post for a reminder. Hand assembly took about two hours, and this was the first time any of the Yellowstone prototypes have worked straight away without needing any troubleshooting or fixes. The board has only been through one superficial test so far, confirming the ROM contents and booting a 5.25 inch disk, but I’m feeling optimistic it’s a winner.

After going through board v1.0, v2.0, v2.1, and v2.2, I’m sincerely hoping that this will be the final hardware version. The return of the DIP switch is the most visible change here – now the much-discussed -12V supply can be manually enabled or disabled. Leaving it enabled will almost always be OK, but there are a couple of polyfuses to protect the hardware just in case. There’s also a fix in v2.2 for a minor problem that prevented an Apple 3.5 Drive’s eject button from working if the drive was plugged into Yellowstone’s connector #2.

There are still some software issues to clean up, but (crossing my fingers) I think I can see the finish line now.

Just for fun, here’s a shot of the new Yellowstone board along with all of the disk drives I’ve amassed for testing. All of these will work with Yellowstone, and many others too.

And a bonus feature: here’s a peek at a 50 pin Apple peripheral card breakout board that I whipped up. It has all the signals labeled, because I don’t trust myself while debugging. With this breakout board, it’s possible to run a peripheral card on a breadboard instead of inside the Apple II. That’s exactly what I’m doing with the work-in-progress version of the Yellowstone tester shown here.

Read 6 comments and join the conversation 

6 Comments so far

  1. Buddy - September 2nd, 2021 6:42 pm

    Super awesome work!

  2. GaryFDes - September 2nd, 2021 7:22 pm

    Congratulations! Love the blue color. What an achievement. You should be proud.

  3. Ricshaw - September 2nd, 2021 9:51 pm

    Congratulations, you have worked so hard to get this board to this stage, and you are to be commended. I look forward to the release, as my Apple Liron card is broken.

  4. Byte Knight - September 3rd, 2021 12:15 pm

    Nice job – way to see this project through until the end!

  5. Steve - September 3rd, 2021 1:12 pm

    Thanks, it’s not done yet but it’s definitely getting closer.

  6. Joel Mc - September 3rd, 2021 3:27 pm

    I can tell it’s been a journey. You’ve done an amazing piece of work here Steve!

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