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Issues using SX1280 LoRa Transceiver (LAMBDA80 module by RFSolutions) in Ranging Mode

Semtech Transceivers
#1

Hi,

This is Aditya here, I’ve been attempting to use SEMTECH SX1280s in ranging mode for a geolocation project. I’ve created an MBED project importing SX1280Lib (https://os.mbed.com/teams/Semtech/code/SX1280Lib/).

We are using the RFSolutions LAMBDA80 LoRa Transceiver with an integrated SX1280. We are using the STM32L476VG Discovery Board for development and testing. I’ve used this for several years and have verified the pins used and confirmed there are no conflicts on GPIO pins. My team intends to move to another STM dev board for the final product after a proof of concept with the board we already own.

I tried initialising two LAMBDA80 transceivers on identical microcontrollers to start ranging requests with a rubber ducky antenna. Since this was failing, I simplified to a single transceiver in hopes to debug the issue.

I followed the instructions in the manual to initialise and send ranging requests with a timeout of 1 second from a single LAMBDA80 module. I have verified the steps for initialisation have been performed correctly:

SetModulationParams: SF7, 1600KHz B/W, 4:5 Coding rate
SetPacketParams:
    PacketType: RANGING
    PreambleLength: 8
    HeaderType: Variable length
    PayloadLength: 10
    CRC: On
    InvertIQ: Yes

SetRfFrequency: 2450000000
SetTXParams: Output power of 13dB, 20us rampup
SetDeviceRangingAddress: A ranging address of 0x0 is used for simplicity.
SetDioIrqParams: The onTX, onRX, etc. interrupt callbacks are initialised correctly on the microcontroller.
    SetRangingRole: Master

Wherever possible, I’ve verified my STM microcontroller is sending the correct commands to the SX1280 module using a digital signal analyzer. After the above initialisation is done, I start ranging with:

SetTX(TickSize=4000US, 250) for a 1second timeout.

With these settings, I notice that a timeout callback never occurs. In fact, inspecting with a digital signal analyzer shows that no DIO callback interrupt ever comes from the LAMBDA80 to the microcontroller.

With this issue, our project is at a standstill. Similar issues weren’t discussed on forums so we are lost as to how to progress from here.

Could anyone please give us some advice on what else to try, and where to go?

Thanks!