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KernelinsideTasks and co-routines

Updated Jul 2025

FreeRTOS co-routines

[More about co-routines...]

Implementing a Co-Routine

A co-routine should have the following structure:

1void vACoRoutineFunction( CoRoutineHandle_t xHandle,
2                          UBaseType_t uxIndex )
3{
4    crSTART( xHandle );
5

6    for( ;; )
7    {
8        -- Co-routine application code here. --
9    }
10

11    crEND();
12}

The type crCOROUTINE_CODE is defined as a function that returns void and takes an CoRoutineHandle_t and an index as its parameters. All functions that implement a co-routine should be of this type (demonstrated above).

Co-routines are created by calling xCoRoutineCreate().

Points to note:

  • All co-routine functions must start with a call to crSTART().

  • All co-routine functions must end with a call to crEND().

  • Co-routine functions should never return so are typically implemented as a continuous loop.

  • Many co-routines can be created from a single co-routine function. The uxIndex parameter is provided as a means of distinguishing between such co-routines.