SPI Data Pins (Fixed)
The three SPI data pins (MOSI/MISO/SCK) are hardwired to these three pads, which are use for the default SPI interface on all Feathers:
SPI Control Pins (Flexible)
You also need three more pins to control the radio: CS, RST and IRQ
Since there is no guaranteed Feather pin that is interrupt-capable, we set it up so you can fly-wire these three to any three pins available. For the non-Serial/IC pins on the right, we name them A thru F. We also indicate the RX/TX/SDA/SCL pins if you need to use those:
Wire them with three short jumpers like so:
RFM GPIO
There's some other GPIO pins that you may want to use - they can be configured to give you notice of things like packet completion or incoming data. They're all on the left. DIO0 is also known as IRQ so we don't have that duplicated on the left breakouts
Antenna
For an antenna, you have three options:
- Plain wire antenna (cut a quarter-wavelength piece and solder it into the pad/hole
- uFL connector (not included), which can be soldered and then used to attach a uFL antenna or adapter
- SMA edge-launch (not included), for use with any SMA connector
