Run at Velocity via SPI

FlowBo commented 5 years ago

Hej, I'm trying to implement a homing routine with Stallguard. (TMC5160) Normally I'm running the drivers via SPI in Position mode. For homing I switch to Velocity mode. But since I'm not using the step/dir pins I wonder how to get the Stepper running at a constant velocity? I have set the VMAX and AMAX but the motor does not move. Is there a specific command like "Start" or "run"?

teemuatlut commented 5 years ago

You can refer to my unfinished TRAMS code. It's quite old at this point but as the chips are very similar and I did have homing working, you should be able to get started from there.

https://github.com/teemuatlut/Marlin/blob/trams-updated/Marlin/TRAMS.cpp#L77

FlowBo commented 5 years ago

Thanks. revisiting what I wanted to achieve I decided to go for positioning mode as it is also done in the example. Reasons:

if something goes wrong while homing in velocity mode the motor would stall indefinitely. With positioning an end of the routine is defined
To max travel distance for homing is defined by the physical structure

I post my code here for others as a starting point:

initSG(){
  driver.rms_current(200);
  driver.sgt(3);
  driver.sg_stop(true);
  driver.TCOOLTHRS(80000);
  driver.AMAX(10000); 
  driver.VMAX(100000);
  driver.XACTUAL(0);
  driver.XTARGET(int(maxTavelDistance*1.5));
}

updateHomingRoutine(){
  if (driver.status_sg() == true){
    driver.RAMPMODE(3);
    homed = true;
    driver.XACTUAL(0);
    driver.XTARGET(0);
    driver.sg_stop(false);
    // RESET YOUR MOTIONCURVE VALUES  AFTER HOMING
  }
}

teemuatlut / TMCStepper

Run at Velocity via SPI #11