Question

How do I reset an ATmega168/328 in software?

Answer

The ATmega168/328 lacks a software reset instruction. Using the watchdog timer a program can reset the microcontroller by not toggling the watchdog flag. If you are using the Arduino bootloader this may require a modification to the bootloader.

Alternatively software can trigger a hardware reset by triggering a one-shot that is connected to the reset pin.

For more details about software reset see ZB1 Software Reset