The ATMEGA256RFR2 Xplained Pro kit contains two crystals that can
be used as clock sources for the ATmega256RFR2 device. Each crystal has a cut-strap next to
it that can be used to measure the oscillator allowance. This is done by cutting the strap
and adding a resistor across the strap. More information about oscillator allowance and
safety factor can be found in appnote AVR4100.
Table 1. External 32.768kHz
Crystals| Pin on ATmega256RFR2 |
Function |
|---|
| PG3 |
TOSC2, crystal output |
| PG4 |
TOSC1, crystal input |
Table 2. External 16MHz
Crystals| Pin on ATmega256RFR2 |
Function |
|---|
| XTAL1 |
Crystal input |
| XTAL2 |
Crystal output |