14.3.2.1.3 External Reset (RESET)

The RESET pin requires a noise filter that eliminates short, low-going pulses. Filtering the input assures that an external Reset event is only issued when the RESET has been low for a minimum amount of time. See the Electrical Characteristics section for the minimum pulse width of the RESET signal.

The external Reset is enabled by configuring the Reset Pin Configuration (RSTPINCFG) bit field in the System Configuration 0 (FUSE.SYSCFG0) fuse.

When enabled, the external Reset requests a Reset as long as the RESET pin is low. The device will stay in Reset until the RESET pin is high again.

For specific devices (e.g., AVR SD), the RESET pin is permanently allocated to the RESET function and always enabled, and configuration of the Reset Pin is impossible.