So the modular board, the circuit board that was going to solve all my Mitochondrion problems, what I spent about a month designing, and finally managed to make last weekend, has a major problem. The problem is, I plug it in and just wierd stuff happens. Things that really shouldn’t be.
So after a week of staring at it, thinking, testing, re-thinking and swearing, I’d found 9 mistakes. Some were bleedin obvious, like bits that didn’t work coz I’d forgotten to connect them up. So fix that, no probs. Some were easy to diagnose – the chip couldn’t be programmed coz it was always reseting itself, coz I’d connected the reset pin to the voltage that means “reset”, instead of the voltage that means “don’t reset”. Okay, fixed all that.
But it was still doing just plain wierd stuff. Obviously, something was still wrong. Big, horrible wrong. So I slept on it. And then there was another hour of poking until, yup, finally spotted it.
The chips that switch the leccy around (Darlington arrays for the technical) are tiny and look like this:
There’s only two ways that you can connect one up – the right way, with the top end at the top, or the wrong way, top end at the bottom. Yup, I’d put them in the wrong way around. Both of them. So the power wires are connected to the signal pins and vice versa. Hence, wierd stuff.
Fixed it, it works.
You know, it’s taken me many years of training, education and experience to get to the point where I can make this kind of mistake. The average man in the street can only dream of making this kind of screw up.
I am clevur.