Ok, I finally got the board populated. The MCU is powered, and I found the SAME51J19 bootloader. Kudos to jepler! Unfortunately my solder station is out of order, and I can’t get a decent connection without soldering the SWD pins to flash. I was able to reflow without glue, using two different solder pastes with different melting points. To fill the vias, going to the bridges, I need to remove the solder resist from the bottom side as seen on the main power vias. There was a error in the TMC2209 design (I somehow missed a cap), so that part will have to wait. But hay! It’s definitely progress. I’m exited to se how well the Stepper support is for simpleFoc. Apparently the best and most power efficient way to drive a stepper is to treat it as a bldc with 2 phases (closed loop current control). This will be my focus for motor control with this board. The disadvantage with open loop steppers is the lag of speed due to the time it takes to charge the coils, since there is so many poles.
Here is a webinar on closed loop steppers ( skip to 17m 30s for the important part).
