Static Scheduling

If several level 0 interrupt requests are pending at the same time, the one with the highest priority is scheduled for execution first. The CPUINT.LVL0PRI register makes it possible to change the default priority. The Reset value for CPUINT.LVL0PRI is zero, resulting in a default priority as shown in the following figure. As the figure shows, IVEC0 has the highest priority, and IVECn has the lowest priority.

Figure 1. Static Scheduling when CPUINT.LVL0PRI is Zero

The default priority can be changed by writing to the CPUINT.LVL0PRI register. The value written to the register will identify the vector number with the lowest priority. The next interrupt vector in IVEC will have the highest priority, see the following figure. In this figure, the value Y has been written to CPUINT.LVL0PRI, so that interrupt vector Y+1 has the highest priority. Note that in this case, the priorities will "wrap" so that IVEC0 has lower priority than IVECn.

Refer to the Interrupt Vector Mapping of the device for available interrupt requests and their interrupt vector number.

Figure 2. Static Scheduling when CPUINT.LVL0PRI is Different From Zero