Tiny Threads - Tiny Multitasking Threads for Microcontrollers

by: Regulus Berdin

• Idea based on http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html.
• Only 1 byte RAM needed per thread.
• Very small overhead context switching.

Limitations:

• Maximum 254 lines per thread.
• Thread context switching will not work within a switch block.

Usage example:

     TT_DEF(1)
    {
       TT_BEGIN(1);
     while (1)
       {
          ...
          TT_SWITCH(1);
          ...
          ...
          TT_WAIT_UNTIL(1,keypress);
       }
       TT_END(1);
    }
   
    TT_DEF(LED_TASK)
    {
        TT_BEGIN(LED_TASK);
        while (1)
        {
            LedOn();
            delay=DELAY_1_SECOND;
            TT_WAIT_UNTIL(LED_TASK,delay==0);
            LedOff();
            delay=DELAY_1_SECOND;
            TT_WAIT_UNTIL(LED_TASK,delay==0);
        }
        TT_END(LED_TASK);
    }
    
    void main(void)
    {
        ...
        ...
        while(1)
        {
            TT_SCHED(1);
            TT_SCHED(LED_TASK);
        }
    }

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