/* source code for demonstration stepper motor design */
/* http://www.mrob.com/lego/stepper.html              */
/*                                                    */
/* The GNU General Public License version 2.0 applies */
/* to this source code. For more information go to:   */
/* http://www.fsf.org/copyleft/copyleft.html          */

int i;

sub forw
{
  Sleep(1);
  Fwd(OUT_A, 7);
  Sleep(9);
  Off(OUT_A);
}

task m_forw
{
  forw();
}

task m_back
{
  Sleep(1);
  Rev(OUT_A, 7);
  Sleep(9);
  Off(OUT_A);
}

task m_f8
{
  i = 8;
  while(i > 0) {
    forw();
    Sleep(2);
    i = i - 1;
  }
}

task main
{
  while(true) {
    if (Message() == 1) {
      stop m_f8;
      start m_forw;
    } else if (Message() == 2) {
      stop m_f8;
      start m_back;
    } else if (Message() == 3) {
      start m_f8;
    }
    ClearMessage();
    Sleep(1);
  }
}