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mbed-os-example-ble-Advertising
BLE Advertising sample application
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main.cpp
00001 /* mbed Microcontroller Library 00002 * Copyright (c) 2006-2019 ARM Limited 00003 * 00004 * Licensed under the Apache License, Version 2.0 (the "License"); 00005 * you may not use this file except in compliance with the License. 00006 * You may obtain a copy of the License at 00007 * 00008 * http://www.apache.org/licenses/LICENSE-2.0 00009 * 00010 * Unless required by applicable law or agreed to in writing, software 00011 * distributed under the License is distributed on an "AS IS" BASIS, 00012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00013 * See the License for the specific language governing permissions and 00014 * limitations under the License. 00015 */ 00016 00017 #include <events/mbed_events.h> 00018 #include "ble/BLE.h" 00019 #include "ble/Gap.h" 00020 #include "pretty_printer.h" 00021 00022 const static char DEVICE_NAME[] = "BATTERY"; 00023 00024 using namespace std::literals::chrono_literals; 00025 00026 static events::EventQueue event_queue(/* event count */ 16 * EVENTS_EVENT_SIZE); 00027 00028 class BatteryDemo : ble::Gap::EventHandler { 00029 public: 00030 BatteryDemo(BLE &ble, events::EventQueue &event_queue) : 00031 _ble(ble), 00032 _event_queue(event_queue), 00033 _battery_level(50), 00034 _adv_data_builder(_adv_buffer) 00035 { 00036 } 00037 00038 void start() 00039 { 00040 /* mbed will call on_init_complete when when ble is ready */ 00041 _ble.init(this, &BatteryDemo::on_init_complete); 00042 00043 /* this will never return */ 00044 _event_queue.dispatch_forever(); 00045 } 00046 00047 private: 00048 /** Callback triggered when the ble initialization process has finished */ 00049 void on_init_complete(BLE::InitializationCompleteCallbackContext *params) 00050 { 00051 if (params->error != BLE_ERROR_NONE) { 00052 print_error(params->error, "Ble initialization failed."); 00053 return; 00054 } 00055 00056 print_mac_address(); 00057 00058 start_advertising(); 00059 } 00060 00061 void start_advertising() 00062 { 00063 /* create advertising parameters and payload */ 00064 00065 ble::AdvertisingParameters adv_parameters( 00066 /* you cannot connect to this device, you can only read its advertising data, 00067 * scannable means that the device has extra advertising data that the peer can receive if it 00068 * "scans" it which means it is using active scanning (it sends a scan request) */ 00069 ble::advertising_type_t::SCANNABLE_UNDIRECTED, 00070 ble::adv_interval_t(ble::millisecond_t(1000)) 00071 ); 00072 00073 _adv_data_builder.setFlags(); 00074 _adv_data_builder.setName(DEVICE_NAME); 00075 00076 /* we add the battery level as part of the payload so it's visible to any device that scans */ 00077 _adv_data_builder.setServiceData(GattService::UUID_BATTERY_SERVICE, {&_battery_level, 1}); 00078 00079 /* setup advertising */ 00080 00081 ble_error_t error = _ble.gap().setAdvertisingParameters( 00082 ble::LEGACY_ADVERTISING_HANDLE, 00083 adv_parameters 00084 ); 00085 00086 if (error) { 00087 print_error(error, "_ble.gap().setAdvertisingParameters() failed"); 00088 return; 00089 } 00090 00091 error = _ble.gap().setAdvertisingPayload( 00092 ble::LEGACY_ADVERTISING_HANDLE, 00093 _adv_data_builder.getAdvertisingData() 00094 ); 00095 00096 if (error) { 00097 print_error(error, "_ble.gap().setAdvertisingPayload() failed"); 00098 return; 00099 } 00100 00101 /* when advertising you can optionally add extra data that is only sent 00102 * if the central requests it by doing active scanning */ 00103 _adv_data_builder.clear(); 00104 const uint8_t _vendor_specific_data[4] = { 0xAD, 0xDE, 0xBE, 0xEF }; 00105 _adv_data_builder.setManufacturerSpecificData(_vendor_specific_data); 00106 00107 _ble.gap().setAdvertisingScanResponse( 00108 ble::LEGACY_ADVERTISING_HANDLE, 00109 _adv_data_builder.getAdvertisingData() 00110 ); 00111 00112 /* start advertising */ 00113 00114 error = _ble.gap().startAdvertising(ble::LEGACY_ADVERTISING_HANDLE); 00115 00116 if (error) { 00117 print_error(error, "_ble.gap().startAdvertising() failed"); 00118 return; 00119 } 00120 00121 /* we simulate battery discharging by updating it every second */ 00122 _event_queue.call_every( 00123 1000ms, 00124 [this]() { 00125 update_battery_level(); 00126 } 00127 ); 00128 } 00129 00130 void update_battery_level() 00131 { 00132 if (_battery_level-- == 10) { 00133 _battery_level = 100; 00134 } 00135 00136 /* update the payload with the new value */ 00137 ble_error_t error = _adv_data_builder.setServiceData(GattService::UUID_BATTERY_SERVICE, make_Span(&_battery_level, 1)); 00138 00139 if (error) { 00140 print_error(error, "_adv_data_builder.setServiceData() failed"); 00141 return; 00142 } 00143 00144 /* set the new payload, we don't need to stop advertising */ 00145 error = _ble.gap().setAdvertisingPayload( 00146 ble::LEGACY_ADVERTISING_HANDLE, 00147 _adv_data_builder.getAdvertisingData() 00148 ); 00149 00150 if (error) { 00151 print_error(error, "_ble.gap().setAdvertisingPayload() failed"); 00152 return; 00153 } 00154 } 00155 00156 private: 00157 BLE &_ble; 00158 events::EventQueue &_event_queue; 00159 00160 uint8_t _battery_level; 00161 00162 uint8_t _adv_buffer[ble::LEGACY_ADVERTISING_MAX_SIZE]; 00163 ble::AdvertisingDataBuilder _adv_data_builder; 00164 }; 00165 00166 /* Schedule processing of events from the BLE middleware in the event queue. */ 00167 void schedule_ble_events(BLE::OnEventsToProcessCallbackContext *context) 00168 { 00169 event_queue.call(Callback<void()>(&context->ble, &BLE::processEvents)); 00170 } 00171 00172 int main() 00173 { 00174 BLE &ble = BLE::Instance(); 00175 ble.onEventsToProcess(schedule_ble_events); 00176 00177 BatteryDemo demo(ble, event_queue); 00178 demo.start(); 00179 00180 return 0; 00181 }
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