Closing the SAMD21 Pro RF LoRaWAN jumpers: what does that actually do?

Development Boards
1

I planned to use LoRaWAN for remote sensing with the SAMD21’s, so I soldered the jumpers on mine. I connect the SAMD’s to TTN through my Pi+RAK 2245 LoRaWAN gateway just fine to collect data.

But I wanted to go back and run some tests using the Sparkfun SAMD21 Pro RF client/server examples, one on each of my SAMD’s, and they don’t seem to be talking to each other. I checked the frequencies and they match; I’m pretty sure I ran these successfully in client/server mode as a test before I closed the jumpers.

So did closing the jumpers affect the SAMDs so that the client/server examples no longer run? Do I need to craft specially-formatted LoRaWAN packets now to get payloads delivered between SAMDs? If that’s the case, is there a succinct statement of the format for such packets?

Is there a document that states what closing the jumpers actually does, in some detail?

David

2

Hello hdtodd,

You can find the description of closing these jumpers [Here. Closing these jumpers will cause the board to broadcast is a very specific way. If the other boards aren’t configured for this broadcast, then there will be communication issues.

You can easily go back to the default setting by opening these jumpers for your testing.](SparkFun SAMD21 Pro RF Hookup Guide - SparkFun Learn)

3

Brandon,

Thanks. Yes, I’d read that web page (multiple times actually) but didn’t fully understand the implications. I now understand that to mean that the Sparkfun LoRa client-server example codes won’t work if the jumpers are closed to make the Board broadcast as LoRaWAN. Or, at least, won’t work without creating LoRaWAN-formatted packets to send back and forth.

I’m planning to work in LoRaWAN in the long term, but I really don’t want to open and close those jumpers repeatedly.

I’m now presuming that the easiest way to set up a LoRaWAN client-server pair with those jumpers closed is to pull examples of LoRaWAN code that use the LMIC library into the Sparkfun LoRa client-server code, replacing the RF95 calls with LMIC calls. Does that seem like the right track?

David