Stepper Motor Control Question?

Projects Programming
1

In this motor example how does the sketch know what channel or pins to output on?

/* 
 Stepper Motor Control - one revolution
 
 This program drives a unipolar or bipolar stepper motor. 
 The motor is attached to digital pins 8 - 11 of the Arduino.
 
 The motor should revolve one revolution in one direction, then
 one revolution in the other direction.  
 
  
 Created 11 Mar. 2007
 Modified 30 Nov. 2009
 by Tom Igoe
 
 */

#include <Stepper.h>

const int stepsPerRevolution = 200;  // change this to fit the number of steps per revolution
                                     // for your motor

// initialize the stepper library on pins 8 through 11:
Stepper myStepper(stepsPerRevolution, 8,9,10,11);            

void setup() {
  // set the speed at 60 rpm:
  myStepper.setSpeed(60);
  // initialize the serial port:
  Serial.begin(9600);
}

void loop() {
  // step one revolution  in one direction:
   Serial.println("clockwise");
  myStepper.step(stepsPerRevolution);
  delay(500);
  
   // step one revolution in the other direction:
  Serial.println("counterclockwise");
  myStepper.step(-stepsPerRevolution);
  delay(500); 
}
2 
// initialize the stepper library on pins 8 through 11:
Stepper myStepper(stepsPerRevolution, 8,9,10,11);

If you want to know what the pins (8-11) are used for, you would have to look in the library files.

Stepper::Stepper(int number_of_steps, int motor_pin_1, int motor_pin_2, int motor_pin_3, int motor_pin_4)

  if (this->pin_count == 4) {
    switch (thisStep) {
      case 0:    // 1010
      digitalWrite(motor_pin_1, HIGH);
      digitalWrite(motor_pin_2, LOW);
      digitalWrite(motor_pin_3, HIGH);
      digitalWrite(motor_pin_4, LOW);
      break;
      case 1:    // 0110
      digitalWrite(motor_pin_1, LOW);
      digitalWrite(motor_pin_2, HIGH);
      digitalWrite(motor_pin_3, HIGH);
      digitalWrite(motor_pin_4, LOW);
      break;
      case 2:    //0101
      digitalWrite(motor_pin_1, LOW);
      digitalWrite(motor_pin_2, HIGH);
      digitalWrite(motor_pin_3, LOW);
      digitalWrite(motor_pin_4, HIGH);
      break;
      case 3:    //1001
      digitalWrite(motor_pin_1, HIGH);
      digitalWrite(motor_pin_2, LOW);
      digitalWrite(motor_pin_3, LOW);
      digitalWrite(motor_pin_4, HIGH);
      break;
    } 
  }
3

My board is marked A and B by the screw terminal ports. Are the screw terminal ports mapped to pins 8,9,10,11? How does my PCB know to use screw terminal ports or pins? :stuck_out_tongue_closed_eyes:

4

How would I know what there for? I don't have a link or anything to what you have.