Datasheet

About Code Examples

9.7.1 Interrupt Response Time

The interrupt execution response for all the enabled AVR interrupts is four clock cycles minimum. After

four clock cycles, the program vector address for the actual interrupt handling routine is executed. During

this four clock cycle period, the program counter is pushed onto the stack. The vector is normally a jump

to the interrupt routine, and this jump takes three clock cycles. If an interrupt occurs during execution of a

multi-cycle instruction, this instruction is completed before the interrupt is served. If an interrupt occurs

when the MCU is in sleep mode, the interrupt execution response time is increased by four clock cycles.

This increase comes in addition to the start-up time from the selected sleep mode. A return from an

interrupt handling routine takes four clock cycles. During these four clock cycles, the program counter

(two bytes) is popped back from the Stack, the Stack Pointer is incremented by two, and the I-bit in

SREG is set.

ATmega328PB

AVR CPU Core

Datasheet Complete

DS40001906C-page 32