motor_control.hcc

//  motor_control.hcc

/*
 *    Generate pulses to control a modified Futaba S3003 servo
 *    motor.  If one button is pressed, generate a 1 msec pulse
 *    every 20 msec.  If the other button is pressed, generate a
 *    2 msec pulse every 20 msec.  If neither button is pressed,
 *    generate a 1.5 msec pulse.
 *
 *    Use FPGA pin M2, which is connected to expansion header pin
 *    3, for output.
 *
 *    Provide code to interface with the Waveform Analyzer during
 *    simulation.
 *
 *    Illustrates use of two main() functions.
 *    Illustrates use of a chan for synchronization between threads.
 *
 *    Author: C. Vickery
 *    Fall 2003
 *
 */

#if (defined USE_RC200 || USE_RC200E)
#define PAL_TARGET_CLOCK_RATE 50000000
#else
#define PAL_ACTUAL_CLOCK_RATE 1000000
set clock = external "P1"
  with
  {
    extlib  = "DKSync.dll",
    extinst = "1000",         // Period of 1MHz simulated clock
    extfunc = "DKSyncGetSet"
  };
#endif

#include <pal_master.hch>
#include <stdlib.hch>

unsigned 1 motor_pin = 0;   //  The output value

interface bus_out() motor( unsigned 1 out = motor_pin )
  with
  {
#if (defined USE_RC200 || USE_RC200E)
    data  = { "M2" }
#else
    extlib  = "DKConnect.dll",
    extinst = "t(1)",
    extfunc = "DKConnectGetSet"
#endif
  };


//  microsec_delay()
//  ------------------------------------------------------------------
macro proc microsec_delay( microsec )
{
  macro expr count = PAL_ACTUAL_CLOCK_RATE / 1000000 * microsec;
  unsigned (log2ceil( count )) counter;
  counter = count - 1;
  while ( counter != 0 ) counter--;
}

chan unsigned 1 sync;


//  First main()
//  ------------------------------------------------------------------
/*
 *    Generate a synchronizing event every 20 msec.
 */
  void main( void )
  {
    while ( TRUE )
    {
      microsec_delay( 20000 );
      sync ! 1;
    }
  }


//  Second main()
//  ------------------------------------------------------------------
/*
 *    Generate a 1.0, 1.5, or 2.0 msec pulse every 20 msec, depending
 *    on the states of the two pushbuttons.
 *
 *    This version generates no pulses when both buttons are pressed,
 *    which also stops the motor like a 1.5 msec pulse.  You have to
 *    keep sending pulses to get the motor to keep moving.
 *
 */
  void main( void )
  {
    unsigned 1 sync_bit, switch_0, switch_1;


    PalVersionRequire( 1, 2 );
    PalSwitchRequire( 2 );

    while ( TRUE )
    {
      sync ? sync_bit;
      par
      {
        PalSwitchRead( PalSwitchCT( 0 ), &switch_0 );
        PalSwitchRead( PalSwitchCT( 1 ), &switch_1 );
      }
      switch ( switch_1 @ switch_0 )
      {

        case 0b00:
          motor_pin = 1;
          microsec_delay( 1500 );
          motor_pin = 0;
          break;

        case 0b01:
          motor_pin = 1;
          microsec_delay( 1000 );
          motor_pin = 0;
          break;

        case 0b10:
          motor_pin = 1;
          microsec_delay( 2000 );
          motor_pin = 0;
          break;

        case 0b11:
          break;

      }
    }
  }