The main feature of ATmega256RFR2 Xplained Pro is to show the RF capability of the ATmega256RFR2 device. This device has bidirectional differential antenna pins, which are fed through a balun (Johanson Technology, 2450BM15A0015) to create a single unbalanced output/input. This kit has a passive analog RF switch (Skyworks Solutions Inc, AS222-92LF) connected to the unbalanced output of the balun. The switch is driven by the DIG1 and DIG2 pins of the ATmega256RFR2, which feature Antenna Diversity to enable the device to automatically select the best signal from two antennas (can also be selected manually). The output of the switch is connected to a ceramic chip antenna (Johanson Technology, 2540AT18D0100) and a SMA connector for external antennas.
| Pin on ATmega256RFR2 | |
|---|---|
| RFP | RF balanced output (Positive) |
| RFN | RF balanced output (Negative) |