[analysis notes] source code analysis of siliconlabs efr32bg22 Bluetooth mesh sensorclient

Hardware environment : SLTB010A(BRD4184A Rev A02 / EFR32BG22C224F512IM40)
Software environment : SimplicityStudio5/gecko_sdk_3.2.3
Analytical engineering : Bluetooth Mesh SensorClient

It's a bad remedy BluetoothMesh Related knowledge , For the first time contact SiliconLabs chip , Search the whole network , There are so few Chinese materials , Another person has been gnawing at many official documents in English , Understand the burning 、 compile 、 Debugging and other basic knowledge , But the way of software development is still in the clouds , Then start to analyze the source code to understand SiliconLabs Source code framework , Finally, I know how to play with this chip .

This chapter mainly analyzes the problems after the equipment has been connected to the network SensorClinet Power on operation process , It should be the only one in the whole network .

The code structure ：

main There is one while(1), Keep querying and getting from the event queue mesh event , And then we can do different processing according to different events .

void sl_btmesh_step(void)
{
  sl_btmesh_msg_t evt;

  uint32_t event_len = sl_btmesh_event_pending_len();
  // For preventing from data loss, the event will be kept in the stack's queue
  // if application cannot process it at the moment.
  if ((event_len == 0) || (!sl_btmesh_can_process_event(event_len))) {
    return;
  }

  // Pop (non-blocking) a Bluetooth stack event from event queue.
  sl_status_t status = sl_btmesh_pop_event(&evt);
  if(status != SL_STATUS_OK){
    return;
  }
  sl_btmesh_process_event(&evt);
}

void sl_btmesh_process_event(sl_btmesh_msg_t *evt)
{
  sl_btmesh_handle_btmesh_logging_events(evt);
  sl_btmesh_handle_provisioning_decorator_event(evt);
  sl_btmesh_factory_reset_on_event(evt);
  sl_btmesh_handle_sensor_client_on_event(evt);
  sl_btmesh_on_event(evt);
}

Source code overview ：

It mainly analyzes three events , When the network has been accessed , And the device nodes respond , There are only three events ：
1. sl_btmesh_evt_node_initialized_id
2. sl_btmesh_evt_sensor_client_descriptor_status_id
3. sl_btmesh_evt_sensor_client_status_id

One 、sl_btmesh_evt_node_initialized_id

The event sent after the Bluetooth protocol stack completes initialization after the chip is powered on ( guess )

Analysis and summary ：

1. If you have access to the network , Then initialize the sensor client model : sl_btmesh_sensor_client_init();

[sl_btmesh_sensor_client.c]sl_btmesh_handle_sensor_client_on_event(evt);    //  important ： initialization  sensor client  Model 
case sl_btmesh_evt_node_initialized_id:
if (evt->data.evt_node_initialized.provisioned)
    mesh_sensor_client_init();
    --> sl_btmesh_sensor_client_init(); //  Initialize the sensor client model .Sensor Client  There is no internal configuration , It only activates the models in the Bluetooth grid stack .

2. If you have access to the network , Then start the single timer , If you are not connected to the network, publish a broadcast to let the configurator know , Waiting to be configured for network access

[app.c]sl_btmesh_on_event(evt); //  important :  If already configured ,  Then start the single timer ,  If it is not configured, start broadcasting ,  Waiting for configuration .
--> case sl_btmesh_evt_node_initialized_id:
    --> handle_node_initialized_event(&(evt->data.evt_node_initialized));
        if (evt->provisioned)    //  If the device has been configured ( That is, it has been connected to the network )
            sl_simple_timer_start(..., DEVICE_REGISTER_SHORT_TIMEOUT(100), app_update_registered_devices_timer_cb,..., true);
        else                    //  Turn on the broadcast and wait for the configuration to access the network 
            sl_btmesh_node_start_unprov_beaconing(PB_ADV | PB_GATT);

3. The single timer will clear the list of registered devices first , And record the temperature sensor of interest ID, Then start the search for the specified Sensor ID, Restart cycle 2 Second timer requests data

[app.c]app_update_registered_devices_timer_cb()
--> [sl_btmesh_sensor_client.c]sl_btmesh_sensor_client_update_registered_devices(property:current_property(0x004f))
    registered_devices.count = 0; //  Clear the list of registered devices 
    memset(registered_devices.address_table, 0, sizeof(registered_devices.address_table));
    registering_property = property; //  Will default to the temperature sensor to be registered ID Put the global variable  0x004f
    sl_btmesh_sensor_client_on_discovery_started(property_id:property);  //  Only the print information is output here 
    --> app_log("BT mesh Sensor Device discovery is started. (property_id: 0x%04x)\r\n", property_id);
    //  a key :  Start exploring the specified Sensor  0x004f,  If there is a node response ,  Will trigger  sl_btmesh_evt_sensor_client_descriptor_status_id  event 
    sc = sl_btmesh_sensor_client_get_descriptor(PUBLISH_ADDRESS(0x0000), BTMESH_SENSOR_CLIENT_MAIN(0), IGNORED(0), NO_FLAGS, property);
    if (SL_STATUS_OK == sc) {
        log_info(SENSOR_CLIENT_LOGGING_START_REGISTERING_DEVICES, property);
        --> #define SENSOR_CLIENT_LOGGING_START_REGISTERING_DEVICES "Registration of devices for property ID %4.4x started\r\n"
    else
        log_btmesh_status_f(sc, SENSOR_CLIENT_LOGGING_REGISTERING_DEVICES_FAILED, property);
        --> #define SENSOR_CLIENT_LOGGING_REGISTERING_DEVICES_FAILED "Registration of devices for property ID %4.4x failed\r\n"
//  a key :  The starting cycle is  2  The second timer sends a request for data at a fixed time 
--> sl_simple_timer_start(..., SENSOR_DATA_TIMEOUT(2000), app_sensor_data_timer_cb, ..., true); 

4. cycle 2 Second timer , Will 2 The frequency of seconds is sent to acquire the specified sensor data of all nodes ( Here is the temperature sensor 0x004f)

[app.c]app_sensor_data_timer_cb
    --> sl_btmesh_sensor_client_get_sensor_data(property:current_property(0x004f));
        sc = sl_btmesh_sensor_client_get(PUBLISH_ADDRESS(0x0000), BTMESH_SENSOR_CLIENT_MAIN(0), IGNORED(0), NO_FLAGS, property);
        if (SL_STATUS_OK == sc)
            log_info(SENSOR_CLIENT_LOGGING_GET_DATA_FROM_PROPERTY, property);
            --> #define SENSOR_CLIENT_LOGGING_GET_DATA_FROM_PROPERTY "Get Sensor Data from property ID %4.4x started\r\n"
        else 
            log_btmesh_status_f(sc, SENSOR_CLIENT_LOGGING_GET_DATA_FROM_PROPERTY_FAIL, property);
            --> #define SENSOR_CLIENT_LOGGING_GET_DATA_FROM_PROPERTY_FAIL "Get Sensor Data from property ID %4.4x failed\r\n"

The source code walkthrough ：

[main.c]main() -> while(1) //  This event will be triggered by the protocol stack after power on 
--> [sl_system_process_action.c]sl_system_process_action()
	--> [sl_event_handler.c]sl_stack_process_action()
		--> [sl_btmesh.c]sl_btmesh_step()
			sl_btmesh_pop_event(&evt); //  Take out  mesh  Event type 
			--> sl_btmesh_process_event(&evt); //  Handle  mest  Event type 
				--> [sl_btmesh_event_log.c]sl_btmesh_handle_btmesh_logging_events(evt); //  This is only used to print the currently received event type 
					--> case sl_btmesh_evt_node_initialized_id:
						app_log("evt:mesh_node_initialized\r\n");
				--> [sl_btmesh_provisioning_decorator.c]sl_btmesh_handle_provisioning_decorator_event(evt);	//  Whether the printout has been configured 
					--> case sl_btmesh_evt_node_initialized_id:
						--> sl_btmesh_on_provision_init_status(provisioned, address, iv_index);
							--> if (provisioned)  //  If the device has been configured ( That is, it has been connected to the network )
									app_show_btmesh_node_provisioned(address, iv_index);
									--> app_log("BT mesh node is provisioned (address: 0x%04x, iv_index: 0x%lx)\r\n", address, iv_index);
								else
									app_log("BT mesh node is unprovisioned, started unprovisioned " "beaconing...\r\n");
				--> [sl_btmesh_factory_reset.c]sl_btmesh_factory_reset_on_event(evt); 			//  Ignore ： Only reset events are processed  sl_btmesh_evt_node_reset_id
				--> [sl_btmesh_sensor_client.c]sl_btmesh_handle_sensor_client_on_event(evt);	//  important ： initialization  sensor client  Model 
					case sl_btmesh_evt_node_initialized_id:
					if (evt->data.evt_node_initialized.provisioned)
						mesh_sensor_client_init();
						--> sl_btmesh_sensor_client_init(); //  Initialize the sensor client model .Sensor Client  There is no internal configuration , It only activates the models in the Bluetooth grid stack .
				--> [app.c]sl_btmesh_on_event(evt); //  important :  If already configured ,  Then start the single timer ,  If it is not configured, start broadcasting ,  Waiting for configuration .
					case sl_btmesh_evt_node_initialized_id:
					--> handle_node_initialized_event(&(evt->data.evt_node_initialized));
						if (evt->provisioned)   //  If the device has been configured ( That is, it has been connected to the network )
							sl_simple_timer_start(..., DEVICE_REGISTER_SHORT_TIMEOUT(100), app_update_registered_devices_timer_cb,..., true);
						else					//  Turn on the broadcast and wait for the configuration to access the network 
							sl_btmesh_node_start_unprov_beaconing(PB_ADV | PB_GATT);

It mainly starts to explore the specified sensor and starts to 2 Seconds is the cycle timer to request the acquisition of sensor data  

[app.c]app_update_registered_devices_timer_cb()
--> [sl_btmesh_sensor_client.c]sl_btmesh_sensor_client_update_registered_devices(property:current_property(0x004f))
	registered_devices.count = 0; //  Clear the list of registered devices 
	memset(registered_devices.address_table, 0, sizeof(registered_devices.address_table));
	registering_property = property; //  Will default to the temperature sensor to be registered ID Put the global variable  0x004f
	sl_btmesh_sensor_client_on_discovery_started(property_id:property);  //  Only the print information is output here 
	--> app_log("BT mesh Sensor Device discovery is started. (property_id: 0x%04x)\r\n", property_id);
	//  a key :  Start exploring the specified Sensor  0x004f,  If there is a node response ,  Will trigger  sl_btmesh_evt_sensor_client_descriptor_status_id  event 
	sc = sl_btmesh_sensor_client_get_descriptor(PUBLISH_ADDRESS(0x0000), BTMESH_SENSOR_CLIENT_MAIN(0), IGNORED(0), NO_FLAGS, property);
	if (SL_STATUS_OK == sc) {
		log_info(SENSOR_CLIENT_LOGGING_START_REGISTERING_DEVICES, property);
		--> #define SENSOR_CLIENT_LOGGING_START_REGISTERING_DEVICES "Registration of devices for property ID %4.4x started\r\n"
	else
		log_btmesh_status_f(sc, SENSOR_CLIENT_LOGGING_REGISTERING_DEVICES_FAILED, property);
		--> #define SENSOR_CLIENT_LOGGING_REGISTERING_DEVICES_FAILED "Registration of devices for property ID %4.4x failed\r\n"
//  a key :  The starting cycle is  2  The second timer sends a request for data at a fixed time 
--> sl_simple_timer_start(..., SENSOR_DATA_TIMEOUT(2000), app_sensor_data_timer_cb, ..., true); 

  The period is 2 Second timer timing acquisition Server All sensor data in the model

//  The period is  2  Second timer timing acquisition  Server  All sensor data in the model 
[app.c]app_sensor_data_timer_cb
	--> sl_btmesh_sensor_client_get_sensor_data(property:current_property(0x004f));
		sc = sl_btmesh_sensor_client_get(PUBLISH_ADDRESS(0x0000), BTMESH_SENSOR_CLIENT_MAIN(0), IGNORED(0), NO_FLAGS, property);
		if (SL_STATUS_OK == sc)
			log_info(SENSOR_CLIENT_LOGGING_GET_DATA_FROM_PROPERTY, property);
			--> #define SENSOR_CLIENT_LOGGING_GET_DATA_FROM_PROPERTY "Get Sensor Data from property ID %4.4x started\r\n"
		else 
			log_btmesh_status_f(sc, SENSOR_CLIENT_LOGGING_GET_DATA_FROM_PROPERTY_FAIL, property);
			--> #define SENSOR_CLIENT_LOGGING_GET_DATA_FROM_PROPERTY_FAIL "Get Sensor Data from property ID %4.4x failed\r\n"

Two 、sl_btmesh_evt_sensor_client_descriptor_status_id

The server node responds to events , Server if the node does not exist , There will be no such event  

Analysis and summary ：
1. When starting the search sensor , If there is a node response , This event will be triggered .
2. It will check whether the current node attribute is the temperature sensor of interest .
3. And check whether the node is in the device list , Add to the equipment list when you are not there .
4. This equipment list is very important , Only the data of nodes in this list will not be ignored .

if (descriptor.property_id == registering_property && number_of_devices < SENSOR_CLIENT_DISPLAYED_SENSORS(5)
    && !mesh_address_already_exists(&registered_devices, evt->server_address)) 
    registered_devices.address_table[number_of_devices] = evt->server_address;
    registered_devices.count = number_of_devices + 1;

The source code walkthrough ：

[main.c]main() -> while(1) //  The incident was caused by  sl_btmesh_sensor_client_get_descriptor()  Trigger 
--> [sl_system_process_action.c]sl_system_process_action()
	--> [sl_event_handler.c]sl_stack_process_action()
		--> [sl_btmesh.c]sl_btmesh_step()
			sl_btmesh_pop_event(&evt); //  Take out  mesh  Event type 
			--> sl_btmesh_process_event(&evt); //  Handle  mest  Event type 
				--> [sl_btmesh_event_log.c]sl_btmesh_handle_btmesh_logging_events(evt); //  This is only used to print the currently received event type 
					--> case sl_btmesh_evt_sensor_client_descriptor_status_id:
						app_log("evt:mesh_sensor_client_descriptor_status\r\n");
				--> [sl_btmesh_provisioning_decorator.c]sl_btmesh_handle_provisioning_decorator_event(evt);	//  Ignore ： This function does not handle this event 
				--> [sl_btmesh_factory_reset.c]sl_btmesh_factory_reset_on_event(evt); //  Ignore ： Only reset events are processed  sl_btmesh_evt_node_reset_id
				--> [sl_btmesh_sensor_client.c]sl_btmesh_handle_sensor_client_on_event(evt);
					case sl_btmesh_evt_sensor_client_descriptor_status_id:
					--> handle_sensor_client_events(&(evt->data.evt_sensor_client_descriptor_status));
						case sl_btmesh_evt_sensor_client_descriptor_status_id:
						--> handle_sensor_client_descriptor_status(&(evt->data.evt_sensor_client_descriptor_status));
							--> [sl_btmesh_sensor.c]mesh_lib_sensor_descriptors_from_buf(&descriptor, evt->descriptors.data, SIZE_OF_DESCRIPTOR); //  Data is converted to a sensor descriptor 							
							//  If at present  mesh  The nature of the event ID That's what we want  registering_property:0x004f,  If it is not in the device registration list, add it to the list 
							uint8_t number_of_devices = registered_devices.count;
							if (descriptor.property_id == registering_property && number_of_devices < SENSOR_CLIENT_DISPLAYED_SENSORS(5)
								&& !mesh_address_already_exists(&registered_devices, evt->server_address)) 
								registered_devices.address_table[number_of_devices] = evt->server_address;
								registered_devices.count = number_of_devices + 1;
								--> [app_out_log.c]sl_btmesh_sensor_client_on_new_device_found(descriptor.property_id, evt->server_address);
									--> app_log("BT mesh Sensor Device (address: 0x%04x, property_id: 0x%04x) is found.\r\n", address, property_id);

3、 ... and 、sl_btmesh_evt_sensor_client_status_id

Server node status response event , Server if the node status is not responding or does not exist , There will be no such event

Analysis and summary ：
1. The packet attached to this event may carry multiple node data , Therefore, it is necessary to split them one by one
2. Filter nodes that are not in the device list , Only the temperature sensor data in the equipment list and of interest will be processed .

The source code walkthrough ：

[main.c]main() -> while(1) //  The incident was caused by  sl_btmesh_sensor_client_get_descriptor()  Trigger 
--> [sl_system_process_action.c]sl_system_process_action()
	--> [sl_event_handler.c]sl_stack_process_action()
		--> [sl_btmesh.c]sl_btmesh_step()
			sl_btmesh_pop_event(&evt); //  Take out  mesh  Event type 
			--> sl_btmesh_process_event(&evt); //  Handle  mest  Event type 
				--> [sl_btmesh_event_log.c]sl_btmesh_handle_btmesh_logging_events(evt); //  This is only used to print the currently received event type 
					--> case sl_btmesh_evt_sensor_client_status_id: //  The address of the printout current response is the group address 、 Unicast address or virtual address 
						app_log("evt:mesh_sensor_client_status %s\r\n", (evt->data.evt_sensor_client_status.client_address & 0xC000) == 0xC000 ? "(group broadcast)" : (evt->data.evt_sensor_client_status.client_address & 0x1000) == 0 ? "(unicast)" : "(virtual)");		
				--> [sl_btmesh_provisioning_decorator.c]sl_btmesh_handle_provisioning_decorator_event(evt);	//  Ignore ： This function does not handle this event 
				--> [sl_btmesh_factory_reset.c]sl_btmesh_factory_reset_on_event(evt); //  Ignore ： Only reset events are processed  sl_btmesh_evt_node_reset_id
				--> [sl_btmesh_sensor_client.c]sl_btmesh_handle_sensor_client_on_event(evt); //  a key :  This function will extract the match Server The sensor data 
					case sl_btmesh_evt_sensor_client_status_id:
					--> handle_sensor_client_events(&(evt->data.evt_sensor_client_descriptor_status));
						case sl_btmesh_evt_sensor_client_status_id:
						-->	static void handle_sensor_client_status(sl_btmesh_evt_sensor_client_status_t *evt)
							{
								uint8_t *sensor_data = evt->sensor_data.data;
								uint8_t data_len = evt->sensor_data.len;
								uint8_t pos = 0;
								while (pos < data_len) 
								{	//  Go through each  Server  Node messages 
									if (data_len - pos > PROPERTY_ID_SIZE) {
										mesh_device_properties_t property_id = (mesh_device_properties_t)(sensor_data[pos] + (sensor_data[pos + 1] << 8));
										uint8_t property_len = sensor_data[pos + PROPERTY_ID_SIZE];
										uint8_t *property_data = NULL;
										//  Only those in the device registry are processed  Service  Node messages 
										if (mesh_address_already_exists(&registered_devices, evt->server_address)) {
											sl_btmesh_sensor_client_data_status_t status;
											uint16_t address;
											uint8_t sensor_idx;
											if (property_len && (data_len - pos > PROPERTY_HEADER_SIZE)) {
												property_data = &sensor_data[pos + PROPERTY_HEADER_SIZE];
											}
											address = evt->server_address;
											sensor_idx = mesh_get_sensor_index(&registered_devices, address);
											status = SL_BTMESH_SENSOR_CLIENT_DATA_NOT_AVAILABLE;
											switch (property_id) {
												......
												case PRESENT_AMBIENT_TEMPERATURE:
													temperature_8_t temperature = SL_BTMESH_SENSOR_CLIENT_TEMPERATURE_UNKNOWN;
													if (property_len == 1) {
														mesh_device_property_t new_property = mesh_sensor_data_from_buf(PRESENT_AMBIENT_TEMPERATURE, property_data);
														temperature = new_property.temperature_8;
														if (temperature == SL_BTMESH_SENSOR_CLIENT_TEMPERATURE_UNKNOWN) {
															status = SL_BTMESH_SENSOR_CLIENT_DATA_UNKNOWN;
														} else {
															status = SL_BTMESH_SENSOR_CLIENT_DATA_VALID;
														}
													} else {
													  status = SL_BTMESH_SENSOR_CLIENT_DATA_NOT_AVAILABLE;
													}
													--> [app_out_log.c]sl_btmesh_sensor_client_on_new_temperature_data(sensor_idx, address, status, temperature);
														if (PRESENT_AMBIENT_TEMPERATURE != app_get_current_property()) {
															return;
														}
														if (SL_BTMESH_SENSOR_CLIENT_DATA_VALID == status) {
															app_log("BT mesh Sensor Temperature (from 0x%04x): %3d.%1d  Abduct C\r\n", address, INT_TEMP(temperature), FRAC_TEMP(temperature));
														} else if (SL_BTMESH_SENSOR_CLIENT_DATA_UNKNOWN == status) {
															app_log("BT mesh Sensor Temperature (from 0x%04x): UNKNOWN\r\n", address);
														} else {
															app_log("BT mesh Sensor Temperature (from 0x%04x): NOT AVAILABLE\r\n", address);
														}
													break;
												......
											}
											pos += PROPERTY_HEADER_SIZE + property_len;
										}
									} else {
										pos = data_len;
									}
								}	
							}

Four 、 Key handling logic

  The above is the core logic processing , As for the logic of key triggering , With the above foundation , It's a lot easier .
app.c By redefining app_button_press.c The key processing callback of is used to intercept key events

[app_button_press.c ]SL_WEAK void app_button_press_cb(uint8_t button, uint8_t duration)
{
  (void)button;
  (void)duration;
}

[app.c]void app_button_press_cb(uint8_t button, uint8_t duration)
{
  (void)duration;
  if (duration == APP_BUTTON_PRESS_NONE) {
	return;
  }
  // button pressed
  if (button == BUTTON_PRESS_BUTTON_0) {
	if (duration < APP_BUTTON_PRESS_DURATION_LONG) {
	  app_log("PB0 pressed\r\n");
	  sensor_client_change_current_property();	//  Press the key briefly to adjust the sensor type of interest 
	} else {
	  app_log("PB0 long pressed\r\n");
	  update_registered_devices();				//  Long press to restart the search for the specified Sensor ID
	}
  } else if (button == BUTTON_PRESS_BUTTON_1) {
	app_log("PB1 pressed\r\n");
	update_registered_devices();
  }
}

[app.c]static void sensor_client_change_current_property(void)
{
  switch (current_property) {
    case PRESENT_AMBIENT_TEMPERATURE:
      current_property = PEOPLE_COUNT;
      break;
    case PEOPLE_COUNT:
      current_property = PRESENT_AMBIENT_LIGHT_LEVEL;
      break;
    case PRESENT_AMBIENT_LIGHT_LEVEL:
      current_property = PRESENT_AMBIENT_TEMPERATURE;
      break;
    default:
      app_log("Unsupported property ID change\r\n");
      break;
  }
}

//  Reference resources  sl_btmesh_evt_node_initialized_id  The third and fourth step of 
void update_registered_devices(void)
{
  sl_status_t sc;
  sl_btmesh_sensor_client_update_registered_devices(current_property);
  sc = sl_simple_timer_start(&app_sensor_data_timer,SENSOR_DATA_TIMEOUT, app_sensor_data_timer_cb, NO_CALLBACK_DATA,true);
  app_assert_status_f(sc, "Failed to start periodic timer\n");
}
		

5、 ... and 、 The way of chip development

1. It can be found that the final results are in the current project app_out_log.c Output
2. and app_out_log.c It's through sl_btmesh_sensor_client.c Inside SL_WEAK Decorated interface to intercept the results
3. When a source file in the project has a connection with SL_WEAK When the modified functions are the same , The compiler will only select the function implementation that compiles the source file .
4. So be familiar with  sl_btmesh_sensor_client.c The logical implementation of , What results need to be achieved again SL_WEAK The modified function is OK .