Where is the Downlink receiving and processing function?

[HNguy.25]

Hello everyone,

Currently, I am working with the example LoRaWAN_End_Node on Nucleo-WL55JC1. I am trying to achieve downlink control. Downlink messages are sent from Chirpstack NS.

Right now, I don't know where the function of receiving and processing downlink packets is, in the LoRaWAN_End_Node. I suspect that it is the function OnRxData in lora_app.c but when I tested, it was not what I wanted.

Can anyone help me on finding where that function is and how to implement new code?

P/s: My next goal is to send a hex (01) from Chirpstack NS to the board so that an LED is turned on.

Thank you in advanced, Huy Nguyen.

[Louis AUDOLY · Accepted solution]

Hello @Community member​ ,

You were right, you can process the data sent to your device in this function regarding the port on which data is sent.

Then you can process the buffer, a parameter of the structure "LmHandlerAppData_s"

  

In the End_Node example, depending of the port used to send data, we process the payload to change the class of the device or blink a LED.

You can already use this example for your use case

Hope my answer helped you!

When your question is answered, please close this topic by choosing Select as Best.

[HNguy.25]

ah so indeed the reception and the processing of downlink packets is in OnRxData in lora_app.c. I also later used another way to test the function and it was as you said.

Thank you for your answer, Huy Nguyen.

[HNguy.25]

@Louis AUDOLY​  ah so indeed the reception and the processing of downlink packets is in OnRxData in lora_app.c. I also later used another way to test the function and it was as you said.

Thank you for your answer, Huy Nguyen.