Device firmware

The next step is to compile and flash the device’s firmware.

Clone the Git repository

Clone the git repository with the example and check out the 0.3.0 tag:

git clone
git checkout 0.3.0

For the next steps, you will need to change into the sub-directory examples/stm32l0xx/lora-discovery/:

cd examples/stm32l0xx/lora-discovery/
If you don’t use the "B-L072Z-LRWAN1" board, you will need to adapt the firmware to match your device and hardware configuration!

Update the device configuration

Locate the Device EUI, Application EUI, and Application Key, you created earlier. Add the keys into the following lines in $HOME/.drogue/config.toml:

app-eui = "<The Application EUI>"
dev-eui = "<The Device EUI>"
app-key = "<The Application Key>"

Next create a directory under lora-discovery named config

mkdir -p config

and create three files therein named


each containing the associated key from above.

Put only the key values. For example, the dev_eui file may contain 63C91E0D1F357A7B, not dev-eui=63C91E0D1F357A7B.

Compile and flash

You must update your toolchain configuration to specify the chip variant you are using. Consult your developer board documentation to determine which chip you have. Update drogue-device/examples/stm32l0xx/.cargo/config accordingly. For instance, if you have a STM32L072CZY6TR chip, you would update as follows:

build-std = ["core"]

[target.'cfg(all(target_arch = "arm", target_os = "none"))']
runner = "probe-run --chip STM32L072CZYx"

To see all of the STM32L072CZ variants supported by probe-run use probe-run --list-chips | grep STM32L072CZ.

The firmware is configured to use 'EU868' as the default region. If you are in another part of the world, you may need to modify examples/stm32l0xx/lora-discovery/src/ accordingly. For instance, in the United States, look for .region(LoraRegion::EU868) and replace it with .region(LoraRegion::US915). The LoraRegion enum, and therefore all your possible choices, is defined in device/src/traits/lora/

You can now compile and flash the firmware. Execute the following command:

You need to have the developer board attached to your computer.
cargo run --release

It may happen that the operation fails, especially when you try to flash the board for the first time. If that’s the case, you can try running the following.

cargo build --release
probe-run target/thumbv6m-none-eabi/release/lora-discovery --connect-under-reset --chip STM32L072CZYx

Checking the result

Once you flashed and started the program, cargo run will keep attached to the application running on the development board. The output should look something like this:

    Finished release [optimized + debuginfo] target(s) in 1.66s
     Running probe-run --chip STM32L072CZ target/thumbv6m-none-eabi/release/lora-discovery
  (HOST) INFO  flashing program (73.77 KiB)
  (HOST) INFO  success!
INFO - Configuring with config LoraConfig { region: Some(EU868), lora_mode: Some(WAN), device_address: None, device_eui: Some(EUI([0, 54, 39, 147, 252, 241, 128, 45])), app_eui: Some(EUI([112, 179, 213, 126, 208, 2, 3, 105])), app_key: Some(AppKey([241, 86, 188, 53, 248, 3, 201, 238, 172, 50, 168, 119, 74, 114, 29, 198])) }
INFO - LoRa driver configured
TRACE - New Session Request
TRACE - Event handled
TRACE - Join Request Sending
TRACE - Phy event
TRACE - Event handled
TRACE - TimeoutRequest: 4500
TRACE - Event handled
TRACE - TimeoutRequest: 5300
TRACE - Phy event
TRACE - Event handled
INFO - Network joined (1)
1 Successfully joined the network

Pay attention to the line indicating that the LoRa network was successfully joined.

Pressing buttons

You can already give it a try, and press the blue button on the board.

But before you do, open up the web console, navigate to the "Spy", and start it, using the Drogue application name you have assigned earlier.

Now you can press the button! This will trigger the device to send some information to the LoRa network. There is no one there to receive yet, it should still work.

INFO - Ticked: 1
INFO - Sending message... (1)
INFO - Message: ping:1
TRACE - Uplink with FCnt 0
TRACE - Phy event
TRACE - Event handled
TRACE - TimeoutRequest: 4500
TRACE - Event handled
TRACE - TimeoutRequest: 5300
TRACE - Phy event
TRACE - Event handled
TRACE - Downlink received               (FcntDown=0)
TRACE - Ack received!
INFO - Message sent! (2)
1 Starting to send the message
2 Message acknowledged by TTN

Be aware that the time from sending to receiving the acknowledgment may be around 5 seconds.

On the web console, you should see the event, as received by Drogue Cloud.

Screenshot of event spy