This section walks you through the basic steps for getting started and running with the external interrupts on Atmel megaAVR devices. The tasks given below simply use the switches and LEDs available on Atmel STK600. Without using STK600, these tasks can be verified by connecting a switch circuit and LED circuit to the port pins directly as shown in Figure 1.
It is to be noted that the first three tasks uses some delay loops inside the interrupt service routine to demonstrate the use of interrupts. Generally it is never recommended to use a delay routine inside the ISR.
Figure 1. Basic LED and Switch
Circuit
