Interfacing the STM32 Nucleo pack LoRa LF with V4

gnorrie · August 25, 2023, 2:29pm

Hi All

I am busy trying to configure Chirpstack to communicate the STM32 Nucleo pack LoRa LF.

I have been able to detect Join Requests and Unconfirmed Uplink messages from my end device in the Chirpstack UI but no join accept. When opening a serial port to the End Device I see it joins successfully.

I am using the dockerised version of the Chirpstack and when checking the debug logs I see the received < level=debug msg="backend/semtechudp: “udp packet from gateway” … protocol_version=1 … >

When I have set up 868 modules in the past protocol_version=2

Would this be the cause of seeing no Join Accept message as I will not receive a TXACK message?

brocaar · August 26, 2023, 4:48pm

You probably want to upgrade your UDP Packet Forwarder I expect that your packet-forwarder doesn’t support the TX_ACK package, and thus ChirpStack will not show the downlinks (JoinAccept, …) in the web-interface. This is also going to cause issues with other downlinks as without TX_ACK, ChirpStack will assume the downlink was not sent by the gateway.

github.com

Lora-net/packet_forwarder/blob/master/PROTOCOL.TXT#L322


      
          That packet type is used by the server to send RF packets and associated 
          metadata that will have to be emitted by the gateway.
          
           Bytes  | Function
          :------:|---------------------------------------------------------------------
           0      | protocol version = 2
           1-2    | random token
           3      | PULL_RESP identifier 0x03
           4-end  | JSON object, starting with {, ending with }, see section 6
          
          ### 5.5. TX_ACK packet ###
          
          That packet type is used by the gateway to send a feedback to the server
          to inform if a downlink request has been accepted or rejected by the gateway.
          The datagram may optionnaly contain a JSON string to give more details on
          acknoledge. If no JSON is present (empty string), this means than no error
          occured.
          
           Bytes  | Function
          :------:|---------------------------------------------------------------------
           0      | protocol version = 2