コルーチンは次の状態の１つを取ることができます：

void vACoRoutineFunction( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
        {
            crSTART( xHandle );
            for( ;; )
            {
                -- Co-routine application code here. --
            }
            crEND();
        }

注意するべきポイント：
　* すべてのコルーチン関数は crSTART () へのコールでスタートしなくてはなりません。
　* すべてのコルーチン関数は crEND () へのコールで終わらなくてはなりません。
　* コルーチン関数は決してreturnしてはならない。典型的には無限ループとして実装されます。
　* 複数のコルーチンが一つのコルーチン関数から作成することができます。
uxIndex パラメータはこのようなコルーチンを区別する手段として提供されます。 下に例を示す

    void vACoRoutineFunction( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
    {
        static char c = 'a';
        // Co-routines must start with a call to crSTART().
        crSTART( xHandle );
        for( ;; )
        {
            // If we set c to equal 'b' here ...
            c = 'b';
            // ... then make a blocking call ...
            crDELAY( xHandle, 10 );
            // ... c will only be guaranteed to still
            // equal 'b' here if it is declared static// (as it is here).
        }
            // Co-routines must end with a call to crEND().
        crEND();
    }

    void vACoRoutineFunction( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
    {
        // Co-routines must start with a call to crSTART().
        crSTART( xHandle );
        for( ;; )
        {
            // It is fine to make a blocking call here,
            crDELAY( xHandle, 10 );
            // but a blocking call cannot be made from within// vACalledFunction().
            vACalledFunction();
        }
        // Co-routines must end with a call to crEND().
        crEND();
    }

    void vACalledFunction( void )
    {
          // Cannot make a blocking call here!
    }

    void vACoRoutineFunction( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
    {
        // Co-routines must start with a call to crSTART().
        crSTART( xHandle );
        for( ;; )
        {
            // It is fine to make a blocking call here,
            crDELAY( xHandle, 10 );

            switch( aVariable )
            {
                case 1 : // Cannot make a blocking call here!
                         break;
                default: // Or here!
            }
        }
        // Co-routines must end with a call to crEND().
        crEND();
    }

    void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
      {
          // Co-routines must start with a call to crSTART().
          crSTART( xHandle );

          for( ;; )
          {
              // Delay for a fixed period.
              crDELAY( xHandle, 10 );

              // Flash an LED.
              vParTestToggleLED( 0 );
          }

          // Co-routines must end with a call to crEND().
          crEND();
      }

これだけ。

    void vApplicationIdleHook( void )
    {
        vCoRoutineSchedule( void );
    }

    void vApplicationIdleHook( void )
    {
        for( ;; )
        {
            vCoRoutineSchedule( void );
        }
    }

    #include "task.h"
    #include "croutine.h"
    #define PRIORITY_0 0
    void main( void )
    {
        // In this case the index is not used and is passed // in as 0.
        xCoRoutineCreate( vFlashCoRoutine, PRIORITY_0, 0 );
        // NOTE:  Tasks can also be created here!// Start the scheduler.
          vTaskStartScheduler();
    }

    #include "task.h"
    #include "croutine.h"

    #define PRIORITY_0        0
    #define NUM_COROUTINES    8

    void main( void )
    {
    int i;

        for( i = 0; i < NUM_COROUTINES; i++ )
        {
            // This time i is passed in as the index.
            xCoRoutineCreate( vFlashCoRoutine, PRIORITY_0, i );
        }

        // NOTE: Tasks can also be created here!

        // Start the scheduler.
        vTaskStartScheduler();
    }

    const int iFlashRates[ NUM_COROUTINES ] = { 10, 20, 30, 40, 50, 60, 70, 80 };
    const int iLEDToFlash[ NUM_COROUTINES ] = { 0, 1, 2, 3, 4, 5, 6, 7 }

    void vFlashCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
    {
        // Co-routines must start with a call to crSTART().
        crSTART( xHandle );

        for( ;; )
        {
            // Delay for a fixed period.  uxIndex is used to index into
            // the iFlashRates.  As each co-routine was created with
            // a different index value each will delay for a different
            // period.
            crDELAY( xHandle, iFlashRate[ uxIndex ] );

            // Flash an LED.  Again uxIndex is used as an array index,
            // this time to locate the LED that should be toggled.
            vParTestToggleLED( iLEDToFlash[ uxIndex ] );
        }

        // Co-routines must end with a call to crEND().
        crEND();
    }

１． crflash.c

２． crhook.c

    void vApplicationIdleHook( void )
    {
        vCoRoutineSchedule( void );
    }