void crDELAY( xCoRoutineHandle xHandle, portTickType xTicksToDelay )crDELAY is a macro. The data types in the prototype above are shown for reference only.
Delay a co-routine for a fixed period of time.
crDELAY can only be called from the co-routine function itself - not from within a function called by the co-routine function. This is because co-routines do not maintain their own stack.
| xHandle | The handle of the co-routine to delay. This is the xHandle parameter of the co-routine function. |
| xTickToDelay | The number of ticks that the co-routine should delay for. The actual amount of time this equates to is defined by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant portTICK_RATE_MS can be used to convert ticks to milliseconds. |
// Co-routine to be created.
void vACoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
{
// Variables in co-routines must be declared static if they must maintain value across a blocking call.
// This may not be necessary for const variables.
// We are to delay for 200ms.
static const xTickType xDelayTime = 200 / portTICK_RATE_MS;
// Must start every co-routine with a call to crSTART();
crSTART( xHandle );
for( ;; )
{
// Delay for 200ms.
crDELAY( xHandle, xDelayTime );
// Do something here.
}
// Must end every co-routine with a call to crEND();
crEND();
}