138
8331B–AVR–03/12
Atmel AVR XMEGA AU
12.5
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 corre-
sponding bit values for the interrupt level configuration of all interrupts is shown in
.
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 han-
dler from a lower level interrupt. When returning from the higher level interrupt handler, the
execution of the lower level interrupt handler will continue.
12.6
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 pri-
ority 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.
12.6.1
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 corre-
sponding offset address within the different modules and peripherals.
Table 12-1.
Interrupt levels.
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