So google is ALWAYS worth a five minute search
I searched on youtube simply with TMC2208
Third video is this one
at 8:30 the teach tech guy mentions a website which is listed in the text below the video
Sean Sadler’s comprehensive instructable to using the 2208 in dynamic UART (mode 3): https://www.instructables.com/id/UART...
additionally the uart-mode configures the stepper-driver
with uart you can adjust
- the current
- the drive-mode
- the microstepping
for making a stepper-motor rotate in uart-mode you still use the step/dir-inputs
This means feeding the stepper-driver in his step/dir-input makes the stepper-motor rotate
even in UART-mode.
Though there might be one reason why it does not work:
damaged driver-chip.
If you have the power-supply connected to the TMC2208-driver-board and you connect or dis-connect the motorwires the chip can be damaged!
This is due to the high voltage-spikes that occur in the moment you dis-connect te wire.
The stepper-motor has coils just like an electric fence and each time a current flows through the coil and you disconnect the power-supply a high voltage-spike occurs
So if you have fiddled around with the motor-wires connecting / disconnecting the motorwires while the power-supply was switched on and connected to the driverboard you might have damaged the driver-board.
So make sure to connect the motorwires with high reliability and always switch off the power-supply before you change anything on the motorwires.
If you have a new and not yet used TMC2208 stepperdriver board
switch powersupply off.
connect all wiring
and then use a small testcode that does nothing more then creaing step-pulses at a rather low frequency to test if the motor rotates at all.
This basic test does not require any kind of uart-communication.
best regards Stefan