More progress, more setbacks to report. First, I realized when I booted up my laptop that I never saved the Arduino code that I wrote the other day. That was dumb. Fortunately it wasn’t much, so I rewrote it. Then I did an optimization pass through my code and changed things that ended up cutting my memory footprint down by 10%. Most of that was F()-wrapping static strings, changing return values to boolean when possible, and using char instead of int when I needed small numbers. (Pro Tip: on the Arduino, boolean and char are the same size!)
As I rewrote the display code, I also added the function that updates the display based on coiling progress, and temporarily hooked it up to the left (home) limit switch to increment the coil number.
I also did more reading up on the DRV8825 driver that I’m using, and traced out where the +5v logic should be connected to the RESET and SLEEP pins and found the point on the board to tap in and hook that up. I also found a ground that wasn’t connected and made a jumper for that, too. More crimping of tiny connector pins, yay!
So after I got it all wired back together, I found it still didn’t energize. Then Marty (who designed the board years ago) dug up the original files for the board and realized that the one he gave me was an early version that didn’t work anyway (the voltage to the Mode0, Mode1, and Mode2 pins was VMOT, 12v in my case, and not VCC, 5v). He’s going to find the newer version of the board and bring one in for me to switch over to. It may have burned out the DRV8825s but I have spares.
Below are pictures of the coiling progress display screen, my crimping “workspace” for the evening, the expanded Arduino connector with the enable pin connected, the driver board after adding VCC connections and ground jumper, and everything hooked up.