Quanternion
Quanternion

Reputation: 13

Pontech & Stepper Motor

Does anyone have any experience in moving a simple 4 lead, bipolar stepper motor with a Pontech Big-Easy Kard and a quick420 board? I am simply trying to take the included Arduino examples of controlling stepper motors, and port them over so that they will operate properly within the Pontech environment. The code I am trying to convert is as follows:

/* 
 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); 
}

The problem that I'm having is that I don't know how to properly convert the part where it defines pins 8,9,10 & 11 as the ones that have the motor leads. I am aware that it does that in the .cpp file. I have included below both Stepper.h and Stepper.cpp

/*
  Stepper.h - - Stepper library for Wiring/Arduino - Version 0.4

  Original library     (0.1) by Tom Igoe.
  Two-wire modifications   (0.2) by Sebastian Gassner
  Combination version   (0.3) by Tom Igoe and David Mellis
  Bug fix for four-wire   (0.4) by Tom Igoe, bug fix from Noah Shibley

  Drives a unipolar or bipolar stepper motor using  2 wires or 4 wires

  When wiring multiple stepper motors to a microcontroller,
  you quickly run out of output pins, with each motor requiring 4 connections. 

  By making use of the fact that at any time two of the four motor
  coils are the inverse  of the other two, the number of
  control connections can be reduced from 4 to 2. 

  A slightly modified circuit around a Darlington transistor array or an L293 H-bridge
  connects to only 2 microcontroler pins, inverts the signals received,
  and delivers the 4 (2 plus 2 inverted ones) output signals required
  for driving a stepper motor.

  The sequence of control signals for 4 control wires is as follows:

  Step C0 C1 C2 C3
     1  1  0  1  0
     2  0  1  1  0
     3  0  1  0  1
     4  1  0  0  1

  The sequence of controls signals for 2 control wires is as follows
  (columns C1 and C2 from above):

  Step C0 C1
     1  0  1
     2  1  1
     3  1  0
     4  0  0

  The circuits can be found at 
  http://www.arduino.cc/en/Tutorial/Stepper
*/

// ensure this library description is only included once
#ifndef Stepper_h
#define Stepper_h

// library interface description
class Stepper {
  public:
    // constructors:
    Stepper(int number_of_steps, int motor_pin_1, int motor_pin_2);
    Stepper(int number_of_steps, int motor_pin_1, int motor_pin_2, int motor_pin_3, int motor_pin_4);

    // speed setter method:
    void setSpeed(long whatSpeed);

    // mover method:
    void step(int number_of_steps);

    int version(void);

  private:
    void stepMotor(int this_step);

    int direction;        // Direction of rotation
    int speed;          // Speed in RPMs
    unsigned long step_delay;    // delay between steps, in ms, based on speed
    int number_of_steps;      // total number of steps this motor can take
    int pin_count;        // whether you're driving the motor with 2 or 4 pins
    int step_number;        // which step the motor is on

    // motor pin numbers:
    int motor_pin_1;
    int motor_pin_2;
    int motor_pin_3;
    int motor_pin_4;

    long last_step_time;      // time stamp in ms of when the last step was taken
};

#endif

Now for Stepper.cpp

/*
  Stepper.cpp - - Stepper library for Wiring/Arduino - Version 0.4

  Original library     (0.1) by Tom Igoe.
  Two-wire modifications   (0.2) by Sebastian Gassner
  Combination version   (0.3) by Tom Igoe and David Mellis
  Bug fix for four-wire   (0.4) by Tom Igoe, bug fix from Noah Shibley  

  Drives a unipolar or bipolar stepper motor using  2 wires or 4 wires

  When wiring multiple stepper motors to a microcontroller,
  you quickly run out of output pins, with each motor requiring 4 connections. 

  By making use of the fact that at any time two of the four motor
  coils are the inverse  of the other two, the number of
  control connections can be reduced from 4 to 2. 

  A slightly modified circuit around a Darlington transistor array or an L293 H-bridge
  connects to only 2 microcontroler pins, inverts the signals received,
  and delivers the 4 (2 plus 2 inverted ones) output signals required
  for driving a stepper motor.

  The sequence of control signals for 4 control wires is as follows:

  Step C0 C1 C2 C3
     1  1  0  1  0
     2  0  1  1  0
     3  0  1  0  1
     4  1  0  0  1

  The sequence of controls signals for 2 control wires is as follows
  (columns C1 and C2 from above):

  Step C0 C1
     1  0  1
     2  1  1
     3  1  0
     4  0  0

  The circuits can be found at 

http://www.arduino.cc/en/Tutorial/Stepper


 */


#include "WProgram.h"
#include "Stepper.h"

/*
 * two-wire constructor.
 * Sets which wires should control the motor.
 */
Stepper::Stepper(int number_of_steps, int motor_pin_1, int motor_pin_2)
{
  this->step_number = 0;      // which step the motor is on
  this->speed = 0;        // the motor speed, in revolutions per minute
  this->direction = 0;      // motor direction
  this->last_step_time = 0;    // time stamp in ms of the last step taken
  this->number_of_steps = number_of_steps;    // total number of steps for this motor

  // Arduino pins for the motor control connection:
  this->motor_pin_1 = motor_pin_1;
  this->motor_pin_2 = motor_pin_2;

  // setup the pins on the microcontroller:
  pinMode(this->motor_pin_1, OUTPUT);
  pinMode(this->motor_pin_2, OUTPUT);

  // When there are only 2 pins, set the other two to 0:
  this->motor_pin_3 = 0;
  this->motor_pin_4 = 0;

  // pin_count is used by the stepMotor() method:
  this->pin_count = 2;
}


/*
 *   constructor for four-pin version
 *   Sets which wires should control the motor.
 */

Stepper::Stepper(int number_of_steps, int motor_pin_1, int motor_pin_2, int motor_pin_3, int motor_pin_4)
{
  this->step_number = 0;      // which step the motor is on
  this->speed = 0;        // the motor speed, in revolutions per minute
  this->direction = 0;      // motor direction
  this->last_step_time = 0;    // time stamp in ms of the last step taken
  this->number_of_steps = number_of_steps;    // total number of steps for this motor

  // Arduino pins for the motor control connection:
  this->motor_pin_1 = motor_pin_1;
  this->motor_pin_2 = motor_pin_2;
  this->motor_pin_3 = motor_pin_3;
  this->motor_pin_4 = motor_pin_4;

  // setup the pins on the microcontroller:
  pinMode(this->motor_pin_1, OUTPUT);
  pinMode(this->motor_pin_2, OUTPUT);
  pinMode(this->motor_pin_3, OUTPUT);
  pinMode(this->motor_pin_4, OUTPUT);

  // pin_count is used by the stepMotor() method:  
  this->pin_count = 4;
}

/*
  Sets the speed in revs per minute

*/
void Stepper::setSpeed(long whatSpeed)
{
  this->step_delay = 60L * 1000L / this->number_of_steps / whatSpeed;
}

/*
  Moves the motor steps_to_move steps.  If the number is negative, 
   the motor moves in the reverse direction.
 */
void Stepper::step(int steps_to_move)
{  
  int steps_left = abs(steps_to_move);  // how many steps to take

  // determine direction based on whether steps_to_mode is + or -:
  if (steps_to_move > 0) {this->direction = 1;}
  if (steps_to_move < 0) {this->direction = 0;}


  // decrement the number of steps, moving one step each time:
  while(steps_left > 0) {
  // move only if the appropriate delay has passed:
  if (millis() - this->last_step_time >= this->step_delay) {
      // get the timeStamp of when you stepped:
      this->last_step_time = millis();
      // increment or decrement the step number,
      // depending on direction:
      if (this->direction == 1) {
        this->step_number++;
        if (this->step_number == this->number_of_steps) {
          this->step_number = 0;
        }
      } 
      else { 
        if (this->step_number == 0) {
          this->step_number = this->number_of_steps;
        }
        this->step_number--;
      }
      // decrement the steps left:
      steps_left--;
      // step the motor to step number 0, 1, 2, or 3:
      stepMotor(this->step_number % 4);
    }
  }
}

/*
 * Moves the motor forward or backwards.
 */
void Stepper::stepMotor(int thisStep)
{
  if (this->pin_count == 2) {
    switch (thisStep) {
      case 0: /* 01 */
      digitalWrite(motor_pin_1, LOW);
      digitalWrite(motor_pin_2, HIGH);
      break;
      case 1: /* 11 */
      digitalWrite(motor_pin_1, HIGH);
      digitalWrite(motor_pin_2, HIGH);
      break;
      case 2: /* 10 */
      digitalWrite(motor_pin_1, HIGH);
      digitalWrite(motor_pin_2, LOW);
      break;
      case 3: /* 00 */
      digitalWrite(motor_pin_1, LOW);
      digitalWrite(motor_pin_2, LOW);
      break;
    } 
  }
  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;
    } 
  }
}

/*
  version() returns the version of the library:
*/
int Stepper::version(void)
{
  return 4;
}

Upvotes: 1

Views: 2022

Answers (2)

Jacob Christ
Jacob Christ

Reputation: 16

It looks like the Arduino library is meant to energize the windings of a stepper directly. The BigEasy has an Allegro stepper driver chip that takes step and direction input. They are apples and oranges. You can use the AccelStep library with the BigEasy and it has already been ported to chipKIT.

Upvotes: 0

Kathy
Kathy

Reputation: 41

I'm assuming you mean the quick240 board since I couldn't find a quick420. If I understand your question, you are trying to map stepper function pins to pins identified by array values used by MPIDE?

Pin 8 is really Port B, pin 0 (PB0) which translates to C1IO3 (pin RB0 on the schematic) Pin 9 is Port B, pin 1 which translates to C0IO3 (pin RB1) Pin 10 is PB2 translates to C1IO1 (pin RB2) Pin 11 is PB3 translates to C1IO0 (pin RB3)

C identifies the card slot while IO number is the pin of the slot. The array uses card slot and pin for indices, so that should get you most of the way there.

To do this yourself, use an Arduino pinout to get the port number for the pin and then the quick240 schematic to translate the port and pin to card slot and IO number. Of you can translate in the other direction if you wish.

Upvotes: 1

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