6.4 unsigned char rtkSliceScaler

This is an unsigned character (8-bit value) that specifies how many kernel ticks should happen before the time slicer forces a context switch. Initialize this before the timer is activated.

If this variable is not initialized, but TIMER_RTK_PREEMPT is defined and timer.S is used, the default number of RTK ticks is 256 (because of 0 wraparound). In other words, if an application does not initialize this variable, a thread is forced to yield every 256 RTK ticks.

De not define TIMER_RTK_PREEMPT (see subsection 5.5 if you do not want to have time slicing.