After a few unsuccessful attempts, I got Smoothie to move my stepper motors on the PrntrBoard controller.
At first the smoothie had a bug in the SPI dirver and was unable to talk to the TMC2130 chips. Fixed that, then the steppers still would not move.
I can see the drivers were sending current, because my power supply would start the fans up, but zero steps. I spend the day trying to diff the configuration between Marlin and Smoothie, but nothing was wrong. Finally caught a bug in the Stepper timers and lo and behold movement.
I’ll make a video of my Rigidbot running Smoothie on STM32 next week.