Ah, I see I have been blessed once again with an ad hominem from the great St. Eric Helgeson, the Only Person Who Understands SCSI On The Internet, YouTube Approved™.
Let's be clear here . Here's a quotation from the draft of the ANSI/ISO SCSI-3 parallel interface standard for single-ended operation. (I don't have access to the final standard and I'm not buying it for the sake of this argument.)
Let's look at the datasheet for a totally random STM32 part, under "Absolute Maximum Ratings":
Blue Pills are so variable that obviously there isn't a single datasheet for it, so this will do. Let's take the 48 mA
per signal in the standard. Let's be nice to the BlueSCSI and pretend there are only 8 data lines, and let's also be charitable to BlueSCSI and say that the actual current is 24 mA. Even this wild standards- and reality-defying underestimate is 192 mA, well above the absolute maximum rating of this chip.
And don't forget, when they say absolute maximum, they mean it. That is the amount of current that can pass through the chip before it is actively damaged.
BlueSCSI works by luck and by guess, is strongly susceptible to variations in the Blue Pill boards used, and is nowhere near standards compliant.
@erichelgeson - we have all cocked up designs. People here haven't seen my cockups but I have made them, dramatically and awfully. I have done really stupid things in my professional career, much worse than this. Mature engineering practice would be to fix it and move on. It's not a huge change. You could fix this in an afternoon. Instead of which you spend your life finding people on the Internet who give your product bad reviews and abusing them, which takes far more energy and achieves very, very little. Get over your insecurities and learn to be an engineer instead of a cult leader. Electricity doesn't care if you bluster. Only the concrete, measurable reality matters. Learn this and your hardware and your demeanour will both improve.