How to build OpenThread with Zephyr and WAMR

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First install west according to the Zephyr's documentation(Ubuntu)

West guide

pip3 install --user -U west

Then run west init in any location you want to install Zephyr:

cd /path/to/where/you/want
west init

Then go to Zephyr's folder, and modify the west.yml, replace the original openthread with the following link:

    - name: openthread
      url: https://github.com/oubotong/openthread
      revision: 1446709296968d23ab30470384c626303012bac3
      path: modules/lib/openthread
    - name: paho
      url: https://github.com/eclipse/paho.mqtt-sn.embedded-c
      revision: e64e817f80

Then run west update to update the new module to your Zephyr project. By far the module have been successfully updated in Zephyr.

The next step is to build environment for OpenThread:

cd modules/lib/openthread
./script/bootstrap
./bootstrap

Before the next step, you need to run the MQTT-SN gateway to connect your device to broker(your border router):

#On your border router
git clone -b experiment https://github.com/eclipse/paho.mqtt-sn.embedded-c   
cd paho.mqtt-sn.embedded-c/MQTTSNGateway       
make SENSORNET=udp6 
make install   
cp -pf Build/MQTT-SNGateway ../../
cp -pf Build/MQTT-SNLogmonitor ../../
cp -pf gateway.conf ../../
cp -pf clients.conf ../../
cp -pf predefinedTopic.conf ../../
make clean

Before running the gateway, we need to modify the configuration of the gateway which is gateway.conf

cd ../
vim gateway.conf

#Change the following configuration
BrokerName=mqtt.eclipse.org #Public broker address for testing
GatewayUDP6Broadcast=FF03::1
GatewayUDP6Port=47193
# UDP6
GatewayUDP6Bind=FFFF:FFFE::1 
GatewayUDP6Port=47193
GatewayUDP6Broadcast=FF03::1
GatewayUDP6If=wpan0 #the interface you use for the border router

To start the gateway, run:

./MQTT-SNGateway -f gateway.conf

Then you will see that the gateway is ready for listening.

Then copy the Zephyr-WAMR folder in zephyr/samples/ and rename the folder to webassembly. The source file of the WASM runtime is in src/main.c which has exposed an interface to connect to the MQTT-SN gateway. The src/test_wasm.h files contains wasm_test_file4which represents the bytecode of wasm module which would access the mqttsnConnectinterface.

To build this example, go to zephyr/samples/webassembly and run(for NRF52840-DK):

west build -b nrf52840dk_nrf52840   . -p always -- -DCONF_FILE="prf_nrf52840_dk.conf  overlay-ot.conf"  -DWAMR_BUILD_TARGET=THUMB    -DWAMR_BUILD_AOT=0
west flash

After a few minutes, you will see that on your border router, you can see the connect message which means the connection is established.

Then open a terminal and start to monitor the UART:

sudo minicom -D /dev/ttyACM0 -b 115200 #the port is which you have your board attached to

You will see that the device role change to router if you run ot state which means the device has joined the network.