Did anybody else see this week’s news about problems with Hubble’s 80s-vintage onboard computer and think: *gasp* My moment in life has arrived! Hold my beer. “Hello, NASA? Did you guys try PR#6? Sometimes the boot disk gets dust on…
Driving 11111111 from RAM through the ‘245 onto the data bus is causing trouble. I can see this clearly – other chips begin to glitch the moment the ‘245 is enabled. But driving 11111111 from the FPGA through the ‘245…
All the clues surrounding Yellowstone’s glitching problems seem to point towards a power supply problem with the ‘245 bus driver and/or the SRAM. The good news is that I now have a “solution” that seems to fix the glitches, and…
I’ve discovered something very useful about the signal glitching problem with Yellowstone: I can reproduce the problem (or a form of it) without booting a disk, and even without any disk drive attached. After many hours, I think I’ve narrowed…
This Yellowstone glitching problem has gone from puzzling to frustrating to potentially project-ending. I’m still not exactly sure what’s going wrong, let alone how to fix it, and I’ve nearly exhausted all my troubleshooting ideas. In the hopes that maybe…
I’m still chasing the cause of a rare Q3 clock glitch on the Yellowstone board. I’ve collected some more data that may help point to the underlying cause. It’s quite a puzzle, but I like a good mystery. I began…
I’ve found a rare clock glitch in the Yellowstone hardware, but I’m not sure how to fix it. This seems to be the source of the “mysterious signal glitching” I mentioned in my previous post, that disappeared after some minor…
I’m still testing the latest prototype of Yellowstone, my FPGA-based universal disk controller for Apple II computers. After a great deal of poking and prodding, the disk controller is now mostly working with all of the Floppy Emu’s disk emulation…
I just spent more than two hours troubleshooting a seemingly simple HTML problem. When I copied and pasted a small section of HTML, the web browser displayed the newly-pasted section differently from the original. The horizontal spacing between some of…
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