New stepper motor driver (TMC2209) runs too slow, how to speed up?

[adamelli]

I left MS2 floating, reads zero volts. This works OK:

const int dirPinX = 13;
const int stepPinX = 12;

const int dirPinY = 8;
const int stepPinY = 7;

void setup()
{
  pinMode(stepPinX, OUTPUT);
  pinMode(dirPinX, OUTPUT);
  pinMode(stepPinY, OUTPUT);
  pinMode(dirPinY, OUTPUT);
}

void loop()
{
  stepX();
  stepY();
}

void stepX()
{
  digitalWrite(stepPinX, HIGH);
  delayMicroseconds(5);
  digitalWrite(stepPinX, LOW);
  delayMicroseconds(50);
}

void stepY()
{
  digitalWrite(stepPinY, HIGH);
  delayMicroseconds(5);
  digitalWrite(stepPinY, LOW);
  delayMicroseconds(50);
}

Here is the program that runs too slow:

/*
   Uno
*/

const int dirPinX = 13;
const int stepPinX = 12;

const int dirPinY = 8;
const int stepPinY = 7;


int resetXcount = 0, resetYcount = 0, stepXcount = 0, stepYcount = 0;

//float deltaTheta = PI/8000;             // Original
float deltaTheta = PI / 8000;             // Adjust this when gear ratio changes
float A = 200;       // Amplitude - scaling (stretching/shifting)
float deltaX = 0, deltaY = 0, theta = 0;
float x_1 = 0, x_2 = 0, y_1 = 0, y_2 = 0;

//----------------------------ONCE----------------------------
void setup()
{
  pinMode(stepPinX, OUTPUT);
  pinMode(dirPinX, OUTPUT);
  pinMode(stepPinY, OUTPUT);
  pinMode(dirPinY, OUTPUT);

  deltaX  = 0;   //(dirPinX, LOW);  // left
  deltaY  = 0;   //(dirPinY, LOW);  // towards
  for (int i = 0; i < 4200; i++)
  {
    stepX();
    stepY();

    digitalWrite(stepPinX, LOW);
    digitalWrite(stepPinY, LOW);
    delayMicroseconds(50);
  }
}

//----------------------------LOOP----------------------------
void loop()
{
  //  1: Circle

  x_1 = cos(theta) * A * 100;
  x_2 = cos(theta + deltaTheta) * A * 100;

  y_1 = 0.9 * sin(theta) * A * 100;         // Original
  y_2 = 0.9 * sin((theta + deltaTheta)) * A * 100; //

  drawLocus();
  theta += deltaTheta;


}

void drawLocus()
{

  deltaX += (x_2 - x_1) * 100;

  if (abs(deltaX) > 100)  // && abs(cos(theta)) < 0.9
  {
    stepX();

    if (deltaX < 0)
    {
      deltaX += 100;
      stepXcount++;
    }
    else
    {
      deltaX -= 100;
      stepXcount--;
    }
  }

  deltaY += (y_2 - y_1) * 100;

  if (abs(deltaY) > 100)  //  && abs(sin(theta)) < 0.95
  {
    stepY();

    if (deltaY < 0)
    {
      deltaY += 100;
      stepYcount++;
    }
    else
    {
      deltaY -= 100;
      stepYcount--;
    }
  }
  digitalWrite(stepPinX, LOW);
  digitalWrite(stepPinY, LOW);
  delayMicroseconds(50);
}





void stepX()
{
  if (deltaX < 0) // Set motor direction clockwise
    digitalWrite(dirPinX, HIGH);
  else
    digitalWrite(dirPinX, LOW);

  digitalWrite(stepPinX, HIGH);
  delayMicroseconds(5);
}


void stepY()
{
  if (deltaY < 0) // Set motor direction clockwise
    digitalWrite(dirPinY, HIGH);
  else
    digitalWrite(dirPinY, LOW);

  digitalWrite(stepPinY, HIGH);
  delayMicroseconds(5);

}

Any suggestions?

[DaveX]

How slow is too slow? Is the 50us delay in each loop making it too slow?

@adamelli

  delayMicroseconds(50);

The TMC2209 only needs 100ns pulse width, so you could put the digitalWrite(stepPinX, LOW); cleanup code inside StepX(), etc...

Oops -- I missed the 4 trig operations per loop. They could take significant time.

[StefanL38]

I looked up the TMC2209-Datasheet
"smallest" microstepping is 1/8

[adamelli]

Silent2209 - FYSETC WIKI

Well that wiki is wrong then. I thought I was running it at 1/2 microstepping. Seems like I'm running it at 1/32.

[StefanL38]

To determine this mount something on the motor-axle that looks to one side. Then run the motor for a certain amout of steps.