Both RFM69 and RFM9x LoRa breakouts have the exact same pinouts. The silkscreen will say RFM69HCW or LoRa depending on which variant you have. If there's a green or blue dot on top of the module, its 900 MHz. If there's a red dot, its 433 MHz
The left-most pins are used for power
- Vin - power in. This is regulated down to 3.3V so you can use 3.3-6VDC in. Make sure it can supply 150mA since the peak radio currents can be kinda high
- GND - ground for logic and power
- EN - connected to the enable pin of the regulator. Pulled high to Vin by default, pull low to completely cut power to the radio.
All pins going into the breakout have level shifting circuitry to make them 3-5V logic level safe. Use whatever logic level is on Vin!
- SCK - This is the SPI Clock pin, its an input to the chip
- MISO - this is the Microcontroller In Serial Out pin, for data sent from the radio to your processor, 3.3V logic level
- MOSI - this is the Microcontroller Out Serial In pin, for data sent from your processor to the radio
- CS - this is the Chip Select pin, drop it low to start an SPI transaction. Its an input to the chip
- RST - this is the Reset pin for the radio. It's pulled high by default which is reset. Pull LOW to turn on the radio
- G0 - the radio's "GPIO 0" pin, also known as the IRQ pin, used for interrupt request notification from the radio to the microcontroller, 3.3V logic level
The radio's have another 5 GPIO pins that can be used for various notifications or radio functions. These aren't used for the majority of uses but are available in case you want them! All are 3.3V logic with no level shifting
This three-way connection lets you select which kind of Antenna you'd like, from the lowest cost wire dipole to the fanciest SMA