ATmega256RFR2 Xplained Pro contains two mechanical buttons. One button is the RESET button connected to the ATmega256RFR2 reset line and the other is a generic user configurable button. When a button is pressed it will drive the I/O line to GND.
| Pin on ATmega256RFR2 | Silkscreen text |
|---|---|
| RSTN | RESET |
| PE4 | SW0 |