As I am searching on libraries that can be used with Lora and arduino I came across on this one: https://github.com/sandeepmistry/arduino-LoRa

Also the RFM9x has the following pinout: RMF 9x Pinout

The data transfer on this chip is achieved via an SPI Interface. Also as I see with the librarie's API specification is that I can setup the pins Slave Select (ss), reset and dio0 with the function:

LoRa.setPins(ss, reset, dio0);

So I should configure the pins reset and dio0 like that:

Parameter Name -> On RMF9x Chip pin
reset -> RESET
dio0 -> DIO0

But I cannot figure out how to connect the ss pin mentioned in the method above, is the on-rmf9x chip the NSS pin?

1 Answer 1


As the library's documentation states the RFM9x's NSS pin should get connected into pin 10. Also as you can see in the following image:

Arduino SPI Interface the pin 10 is the SPI's slave select pin (ss in short) so the NSS pin on the RFM9x is connected into slave select pin.

So in the function:

LoRa.setPins(ss, reset, dio0);

The ss variable takes the number of pin that is conected to RFM9x's NSS pin.

Furthermore it is obvious that the RFM9x's NSS pin is used for SPI's slave select.

  • 1
    Simple clarification: the "N" in "NSS" stands for Negative, i.e., it's an active-low Slave Select. Similar to the NRESET pin of the sx1276, which indicates that reset is active low, unlike what the (incorrect) marking on the module may lead to believe...
    – TvE
    Jul 30, 2018 at 15:59

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