Creating Self-Provisioned BLE Mesh firmware build from Silabs example project "soc-btmesh-sensor-client".
Devloping self-provisioning firmware for BLE Mesh Devices allows for the rapid development of test networks without need a provsioner (usually in the form of a mobile app) to set the network configuration. This is often used in product/network testing, but as Silabs mentions in there API reference material, this should not be used for offical products released to the public.
To create the base project you will need to have Silabs' Simplicity Studio and the BLE Mesh Stack downloaded (as you need for any BLE Mesh firmware). For hardware you will need to BLE Mesh capable devices with Silabs chips. I use dev kits with the efr32mg12p432f1024gl125 chip.
To create a base project in Simplcity Studio, go to the Launcher tab and click on New Project. Select the Project that you think best suits you needs, I choose "soc-btmesh-sensor-client".
With the base project created, The following code changes need to be added inorder to create a self-provisioning network.
In order to pre-configure network details to your devices you will need to enable the test APIs with gecko_bgapi_class_mesh_test_init();
Add this with the other API intit functions contained in gecko_bgapi_classes_init() (see soc-btmesh-sensor-client/app.c).
Each device in the BLE Mesh network needs to have a unique unicast address. If not you risk having mesh messages getting dropped. While there is nothing wrong with creating seperate firmware images for each device (each defining a different 16 bit unicast value), it may be easier to just use the last 4 bytes of the mac address. This will allow one firmware image to be used for all network devices.
The MAC address of each device can be referenced using SYSTEM_GetUnique(). One thing to note, the most significant bit of the unicast address must be 0. Twice now I for got about this and had failures based on my device's MAC address. The solution is to only use the last 15 (not 16) of the MAC for your unicast. For example Unicast = (uint16_t)(SYSTEM_GetUnique() & 0x7FFF); (soc-btmesh-sensor-client/main.c).
One final note. #include "em_system.h" must be in added for SYSTEM_GetUnique to work.
To set the Network and Device Key use gecko_cmd_mesh_node_set_provisioning_data(DevKey, NetKey, 0, 0, Unicast, 0).
To set the App Key use gecko_cmd_mesh_test_add_local_key(1, AppKey,0,0).
The definition of Unicast was shown above. The Net, App, and Dev Keys are all aes_key_128 data type. Below are the keys used in this example code.
/* My Keys*/
aes_key_128 NetKey = {{0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}};
aes_key_128 AppKey = {{0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02}};
aes_key_128 DevKey = {{0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03}};
(see soc-btmesh-sensor-client/Self-Provision_Functions.c)
The models required for each project depend on the end application. For this example code, Generic_Client and Generic_Server are used. The following sub sections break down the steps required to configure a model.
Regardless if a network is self-provisioned or not, any models not included in the default configuration of the base projected need to be added in using the isc file (soc-btmesh-sensor-client/soc-btmesh-sensor-client.isc). It is assumed users of this repo are fimiliar with how to use the isc file to generate the necessary code changes to add new models to there project. The goal of this section is to be a reminder to do so.
Again, regardless if a newtwork is self-provisioned or not, some models will require an init function to be called inorder to function. In the case of the generic server and client models these are gecko_cmd_mesh_generic_client_init() and gecko_cmd_mesh_generic_server_init() (see soc-btmesh-sensor-client/app.c).
To bind your models use the gecko_cmd_mesh_test_bind_local_model_app() API.
Example:
// Bind Models
result = gecko_cmd_mesh_test_bind_local_model_app(0, 0, 0xffff, GENERIC_LEVEL_SERVER)->result;
printf("GENERIC_LEVEL_SERVER: gecko_cmd_mesh_test_bind_local_model_app %x\n\r", result);
result = gecko_cmd_mesh_test_bind_local_model_app(0, 0, 0xffff, GENERIC_LEVEL_CLIENT)->result;
printf("GENERIC_LEVEL_CLIENT: gecko_cmd_mesh_test_bind_local_model_app %x\n\r", result);
(see soc-btmesh-sensor-client/Self-Provision_Functions.c)
To set the publish and sub address for each model use the APIs gecko_cmd_mesh_test_set_local_model_pub() and gecko_cmd_mesh_test_add_local_model_sub().
Example:
//Set Models Pub Address
result = gecko_cmd_mesh_test_set_local_model_pub(0, 0, 0xffff, GENERIC_LEVEL_SERVER, SERVER_PUB_ADD, 5, 0, 3, 0)->result;
printf("SENSOR_CLIENT gecko_cmd_mesh_test_set_local_model_pub %x\n\r", result);
result = gecko_cmd_mesh_test_set_local_model_pub(0, 0, 0xffff, GENERIC_LEVEL_CLIENT, CLIENT_PUB_ADD, 5, 0, 3, 0)->result; //Mulitcast = SERVER_PUB_ADD
printf("GENERIC_LEVEL_CLIENT gecko_cmd_mesh_test_set_local_model_pub %x\n\r", result);
//Set Models Sub Address
result = gecko_cmd_mesh_test_add_local_model_sub(0, 0xffff, GENERIC_LEVEL_SERVER, SERVER_SUB_ADD)->result;
printf("LIGHT_LIGHTNESS_CLIENT gecko_cmd_mesh_test_add_local_model_sub %x\n\r", result);
result = gecko_cmd_mesh_test_add_local_model_sub(0, 0xffff, GENERIC_LEVEL_CLIENT, CLIENT_SUB_ADD)->result;
printf(" vendor gecko_cmd_mesh_test_add_local_model_sub %x\n\r", result);
(see soc-btmesh-sensor-client/Self-Provision_Functions.c)
In this build, each device acts as a client and server. Using an internal timer, the client model will publish a generic level set request every 10 seconds using gecko_cmd_mesh_generic_client_publish().
case TIMDER_ID_SEND_GENERIC_CLIENT_MESSAGE:
printf("Sending Generic Client Message. \r\n");
uint16_t pub_res;
uint8_t byte_array[2] = {0xAA,0xBB};
pub_res = gecko_cmd_mesh_generic_client_publish((uint16)GENERIC_LEVEL_CLIENT, (uint16)ELEM_0, (uint8)Transaction_id, (uint32)TRANS, (uint16)DELAY, (uint16)CLIENT_FLAGS, (uint8)MESH_GENERIC_CLIENT_request_level, (uint8)DATA_LENGHT_CLIENT, byte_array)->result;
printf("Pub Result = %x \n", pub_res);
if(Transaction_id < 255){
Transaction_id++;
}
else{
Transaction_id = 0;
}
break;
When another devices server in this network receives the client request, a gecko_evt_mesh_generic_server_client_request_id event will be triggered. In this example, upon receving a client request a server response is sent via gecko_cmd_mesh_generic_server_response(). Note that the firmware checks that the client message isnt from its own unicast (this confirms message is from another device).
case gecko_evt_mesh_generic_server_client_request_id:
printf("Request From Client Received! \r\n");
struct gecko_msg_mesh_generic_server_client_request_evt_t *client_req =(struct gecko_msg_mesh_generic_server_client_request_evt_t *) &(pEvt->data);
uint16_t client_addr = client_req->client_address;
if( client_addr != Unicast){
printf("Client Node```s Address: %x \r\n", client_addr);
printf("Sending Server Response. \r\n");
uint16_t pub_res;
uint8_t byte_array[4] = {0xAF,0xBF,0xCF,0xDF};
pub_res = gecko_cmd_mesh_generic_server_response((uint16)GENERIC_LEVEL_SERVER, (uint16)ELEM_0, (uint16)SERVER_PUB_ADD, (uint16)APP_KEY_INDEX_0, (uint16)DELAY, (uint16)SERVER_FLAGS, (uint8)MESH_GENERIC_CLIENT_request_level, (uint8)DATA_LENGHT_SERVER, byte_array)->result;
printf("Pub Result = %x \r\n", pub_res);
}
break;
Finally, the client will recieve the servers response as a gecko_evt_mesh_generic_client_server_status_id event. In this example I print the data sent from the server```s response onto the console.
case gecko_evt_mesh_generic_client_server_status_id:
printf("Server Response Received! \r\n");
struct gecko_msg_mesh_generic_client_server_status_evt_t *server_resp =(struct gecko_msg_mesh_generic_client_server_status_evt_t *) &(pEvt->data);
uint16_t server_addr = server_resp->server_address;
printf("Server Node```s Address: %x \r\n", server_addr);
//read message data
printf("Server Data Bytes: ");
for( int di = 0; di < 4; di++){
printf("%x", server_resp->parameters.data[di]);
}
printf("\r\n\n");
break;
Once the firmware has been flash to your devices, check to the serial log to see what the devices is doing. The serial log shown below is from one of my 2 devices flashed with this firmware.
Note that many lines have a number beside the command implimented. This number is the result code for executing the API call. If this values is a non-zero value, then an error has occured.
- Device boots up, Device name is set and node initialize event is triggered:
Device name: ```sensor client 95:0b
node initialized
- Set Network, Device and Aplication Keys:
gecko_cmd_mesh_node_set_provisioning_data 0
gecko_cmd_mesh_test_add_local_key 0
- Bind Models:
GENERIC_LEVEL_SERVER: gecko_cmd_mesh_test_bind_local_model_app 0
GENERIC_LEVEL_CLIENT: gecko_cmd_mesh_test_bind_local_model_app 0
- Set publish and subscribe settings:
GENERIC_LEVEL_SERVER: gecko_cmd_mesh_test_bind_local_model_app 0
GENERIC_LEVEL_CLIENT: gecko_cmd_mesh_test_bind_local_model_app 0
SENSOR_CLIENT gecko_cmd_mesh_test_set_local_model_pub 0
GENERIC_LEVEL_CLIENT gecko_cmd_mesh_test_set_local_model_pub 0
LIGHT_LIGHTNESS_CLIENT gecko_cmd_mesh_test_add_local_model_sub 0
- Set network relay and retransmit settings:
Set Relay gecko_cmd_mesh_test_set_relay 0
gecko_cmd_mesh_test_get_relay returns 1 for enabled
Set Relay gecko_cmd_mesh_test_set_nettx 0
- Node reboots and initializes as provisioned:
got new network key with index 0
Device name: ```sensor client 95:0b```
node initialized
node is provisioned. address:150b, ivi:0
- Initialize generic client and server:
mesh_generic_client_init 0
mesh_generic_server_init 0
- Pubish client request message:
Sending Generic Client Message.
Pub Result = 0
- Receive response from server:
Server Response Received!
Server Node```s Address: 30c1
Server Data Bytes: afbfcfdf
- Receiving a request from another client:
Client Node```s Address: 30c1
Sending Server Response.
11: Sending server response:
Sending Server Response.
Pub Result = 0
Hope this helps, best of luck!
Email: rtquinn2@ncsu.edu