Atmel XMEGA B, User Manual

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121 XMEGA B [DATASHEET]
8291B–AVR–01/2013
11.5 Interrupt level
The interrupt level is independently selected for each interrupt source. For any interrupt request, the PMIC also receives
the interrupt level for the interrupt. The interrupt levels and their corresponding bit values for the interrupt level
configuration of all interrupts is shown in
Table 11-1 .
Table 11-1. Interrupt levels
The interrupt level of an interrupt request is compared against the current level and status of the interrupt controller. An
interrupt request of a higher level will interrupt any ongoing interrupt handler from a lower level interrupt. When returning
from the higher level interrupt handler, the execution of the lower level interrupt handler will continue.
11.6 Interrupt priority
Within each interrupt level, all interrupts have a priority. When several interrupt requests are pending, the order in which
interrupts are acknowledged is decided both by the level and the priority of the interrupt request. Interrupts can be
organized in a static or dynamic (round-robin) priority scheme. High- and medium-level interrupts and the NMI will always
have static priority. For low-level interrupts, static or dynamic priority scheduling can be selected.
11.6.1 Static priority
Interrupt vectors (IVEC) are located at fixed addresses. For static priority, the interrupt vector address decides the priority
within one interrupt level, where the lowest interrupt vector address has the highest priority. Refer to the device datasheet
for the interrupt vector table with the base address for all modules and peripherals with interrupt capability. Refer to the
interrupt vector summary of each module and peripheral in this manual for a list of interrupts and their corresponding
offset address within the different modules and peripherals.
Interrupt Level Configuration Group Configuration Description
00 OFF Interrupt disabled.
01 LO Low-level interrupt
10 MED Medium-level interrupt
11 HI High-level interrupt