TMC2209 UART

main.cpp

/**
 * Author Milan Divkovic
 *
 * You can control the motor with following commands:
 * 0: Disables the motor
 * 1: Enables the motor
 * + or -: Increase or decrease speed in respect to rotation direction
 */

#include <Arduino.h>
#include <TMCStepper.h>

#define STALL_VALUE      50 // [0... 255]
#define TOFF_VALUE        4 // [1... 15]

#define EN_PIN            6 // Enable pin
#define SW_RX             2 // SoftwareSerial receive pin
#define SW_TX             3 // SoftwareSerial transmit pin
//#define SERIAL_PORT Serial1 // HardwareSerial port
#define DRIVER_ADDRESS 0b00 // TMC2209 Driver address according to MS1 and MS2

#define R_SENSE 0.11f // Match to your driver
                      // SilentStepStick series use 0.11
                      // UltiMachine Einsy and Archim2 boards use 0.2
                      // Panucatt BSD2660 uses 0.1
                      // Watterott TMC5160 uses 0.075

// Select your stepper driver type
//TMC2209Stepper driver(&SERIAL_PORT, R_SENSE, DRIVER_ADDRESS);
TMC2209Stepper driver(SW_RX, SW_TX, R_SENSE, DRIVER_ADDRESS);

using namespace TMC2209_n;

int32_t speed = 5000;

void setup() {
  Serial.begin(115200);         // Init serial port and set baudrate
  while(!Serial);               // Wait for serial port to connect
  Serial.println("\nStart...");

  //SERIAL_PORT.begin(115200);
  driver.beginSerial(115200);
  driver.begin();

  // Sets the slow decay time (off time) [1... 15]. This setting also limits
  // the maximum chopper frequency. For operation with StealthChop,
  // this parameter is not used, but it is required to enable the motor.
  // In case of operation with StealthChop only, any setting is OK.
  driver.toff(TOFF_VALUE);

  // VACTUAL allows moving the motor by UART control.
  // It gives the motor velocity in +-(2^23)-1 [μsteps / t]
  // 0: Normal operation. Driver reacts to STEP input.
  // /=0: Motor moves with the velocity given by VACTUAL. 
  // Step pulses can be monitored via INDEX output.
  // The motor direction is controlled by the sign of VACTUAL.
  driver.VACTUAL(speed);

  // Comparator blank time. This time needs to safely cover the switching
  // event and the duration of the ringing on the sense resistor. For most
  // applications, a setting of 16 or 24 is good. For highly capacitive
  // loads, a setting of 32 or 40 will be required.
  driver.blank_time(24);

  driver.rms_current(400); // mA
  driver.microsteps(16);

  // Lower threshold velocity for switching on smart energy CoolStep and StallGuard to DIAG output
  driver.TCOOLTHRS(0xFFFFF); // 20bit max
  
  // CoolStep lower threshold [0... 15].
  // If SG_RESULT goes below this threshold, CoolStep increases the current to both coils.
  // 0: disable CoolStep
  driver.semin(5);

  // CoolStep upper threshold [0... 15].
  // If SG is sampled equal to or above this threshold enough times,
  // CoolStep decreases the current to both coils.
  driver.semax(2);

  // Sets the number of StallGuard2 readings above the upper threshold necessary
  // for each current decrement of the motor current.
  driver.sedn(0b01);

  // StallGuard4 threshold [0... 255] level for stall detection. It compensates for
  // motor specific characteristics and controls sensitivity. A higher value gives a higher
  // sensitivity. A higher value makes StallGuard4 more sensitive and requires less torque to
  // indicate a stall. The double of this value is compared to SG_RESULT.
  // The stall output becomes active if SG_RESULT fall below this value.
  driver.SGTHRS(STALL_VALUE);

  Serial.print("\nTesting connection...");
  uint8_t result = driver.test_connection();

  if (result) {
    Serial.println("failed!");
    Serial.print("Likely cause: ");

    switch(result) {
        case 1: Serial.println("loose connection"); break;
        case 2: Serial.println("no power"); break;
    }

    Serial.println("Fix the problem and reset board.");

    // We need this delay or messages above don't get fully printed out
    delay(100);
    abort();
  }

  Serial.println("OK");

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

void loop() {
  static uint32_t last_time = 0;

  uint32_t ms = millis();

  while (Serial.available() > 0) {
    int8_t read_byte = Serial.read();

    if (read_byte == '0') {
      Serial.print("Motor ");

      if (driver.toff() == 0) {
        Serial.print("already ");
      }

      Serial.println("disabled.");
      driver.toff(0);
    } else if (read_byte == '1') {
      Serial.print("Motor ");

      if (driver.toff() != 0) {
        Serial.print("already ");
      }

      Serial.println("enabled.");
      driver.toff(TOFF_VALUE);
    } else if (read_byte == '+') {
      speed += 1000;

      if (speed == 0) {
        Serial.println("Hold motor.");
      } else {
        Serial.println("Increase speed.");
      }

      driver.VACTUAL(speed);
    } else if (read_byte == '-') {
      speed -= 1000;

      if (speed == 0) {
        Serial.println("Hold motor.");
      } else {
        Serial.println("Decrease speed.");
      }

      driver.VACTUAL(speed);
    }
  }

  if((ms-last_time) > 100 && driver.toff() != 0 && speed != 0) { // run every 0.1s
    last_time = ms;

    Serial.print("Status: ");
    Serial.print(driver.SG_RESULT(), DEC);
    Serial.print(" ");
    Serial.print(driver.SG_RESULT() < STALL_VALUE, DEC);
    Serial.print(" ");
    Serial.println(driver.cs2rms(driver.cs_actual()), DEC);
  }
}

Any idea what could cause this example not to work?
It did work for me in the past with the exact same hardware, and I have no idea why it's not working now....I can clearly see that the stall guard value is lower than the stall guard threshold, but still the motor doesn't stop which as far as I know:
driver.SGTHRS(STALL_VALUE);
Should handle.

The pinouts seems to be correct, so I have no idea what else should be checked.
Thanks.

No idea. Did driver got updated maybe? Haven't been following lately

I have reproduced the problem that pardovot reports. I think you need a routine that turns the motor off. I think you also need to pulse the enable pin to reset the stall flag:
if(driver.SG_RESULT() < STALL_VALUE){
driver.VACTUAL(0);
digitalWrite(EN_PIN,HIGH);
delay(500);
digitalWrite(EN_PIN,LOW);
}

The program still is kind of buggy. Dont know why but it does not always respond to serial input.
Good luck,
Jack

After trying for a week, my tmc2209 is now working in uart mode
thank you!
@metalinspired @pardovot