TMC2300: Setting micro-steps in setup() requires supply reset

[gigiHondaT]

Greetings,

I have been using the release version of this library in combination with the TMC2300-BOB. The breakout board is connected to a RPi Pico which is being programmed via USB/Arduino IDE.

So far I have been able to control the stepper via the legacy- as well as the UART-interface. The issue I came across is, that when I try to set the driver micro-steps inside the setup part of the code, the motor won't start turning until I unplug the motor-supply once. After plugging it back in the motor starts turning. The driver responds just fine with e.g. the micro-step- or RMS-values. If I don't try to set the micro-steps during the setup-part the motor starts without any unplugging. What strikes me as weird, is that the motor runs considerably cooler (with the same current, same speed/ramp) even though the driver reports back the same micro-stepping rate.

I'm probably just doing something wrong, but I haven't been able to wrap my head around what exactly the issue is here. The motor running cooler might have something to do with the autoscaling?

Please see the attached code-snipped I used to ramp the motor up and down:

#include <TMCStepper.h>

#define EN_PIN           4 // Enable
#define SERIAL_PORT Serial1 // HardwareSerial port 
#define DRIVER_ADDRESS 0b00 // TMC2209 Driver address according to MS1 and MS2

#define R_SENSE 0.15f // Match to your driver

bool shaft = false;  // ONLY NEEDED FOR CHANGING DIRECTION VIA UART, NO NEED FOR DIR PIN FOR THIS

TMC2300Stepper driver(SERIAL_PORT, R_SENSE, DRIVER_ADDRESS);
int accel = 0;

void setup() {
  SERIAL_PORT.begin(115200);      // INITIALIZE UART to TMC2300
  Serial.begin(115200);
  delay(500);
  Serial.println(F("Serial Initialized"));

  pinMode(EN_PIN, OUTPUT);
  digitalWrite(EN_PIN, LOW);   

  driver.begin();                // Initialize driver                          
  driver.GSTAT(0b111);           // Reset error flags
  driver.enable_drv(true);       // Unnecessary as 1 is default
  driver.TCOOLTHRS(0x3FF);       // 10bit max

  driver.rms_current(200);       // Set motor RMS current
  Serial.print("current set to:");
  Serial.println(driver.rms_current());

  digitalWrite(EN_PIN, HIGH);

  driver.microsteps(32);          // <--- this requires a supply "reset" to let the motor start
  driver.pwm_autoscale(true);     // Needed for stealthChop
}

void loop() {
  uint16_t msread=driver.microsteps();
  Serial.print(F("Read microsteps via UART to test UART receive : "));   
  Serial.println(msread); 

  Serial.println("TMC2300 UART-Control");
  delay(3000);

  accel=200;
  Serial.print("accel:");
  Serial.println(accel);
  long int spd = 42000;
  Serial.print("spd:");
  Serial.println(spd);

  for (long int i = 0; i <=spd; i = i + accel){
    driver.VACTUAL(i); //SET SPEED OF MOTOR
    delay(100);
  }
  delay(10000);
  for (long int i = spd; i >=0; i = i - accel){
    driver.VACTUAL(i); //SET SPEED OF MOTOR
    delay(100);
  }
  delay(200);
  Serial.println(driver.rms_current());
  shaft = !shaft; // REVERSE DIRECTION
  driver.shaft(shaft); // SET DIRECTION
}