ST / Mbed OS mbed-os-example-ble-Advertising

BLE Advertising sample application

Dependents:   X_NUCLEO_IDB0XA1

This example shows how to advertise a value of battery service data. The battery value is simulated. The battery level is a percentage, with 100% being a fully charged battery and 0% being a fully drained battery. The level starts at 50% and drains every second second, until it hits 10% when it jumps to 100% and continues draining.

source/main.cpp@0:7373a1c9d5b4, 2021-01-14 (annotated)

Committer:
apalmieri
Date:
Thu Jan 14 11:25:30 2021 +0000
Revision:
0:7373a1c9d5b4
Initial commit of BLE Advertising example for X-NUCLEO-IDB05A1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
apalmieri 0:7373a1c9d5b4 1 /* mbed Microcontroller Library
apalmieri 0:7373a1c9d5b4 2 * Copyright (c) 2006-2019 ARM Limited
apalmieri 0:7373a1c9d5b4 3 *
apalmieri 0:7373a1c9d5b4 4 * Licensed under the Apache License, Version 2.0 (the "License");
apalmieri 0:7373a1c9d5b4 5 * you may not use this file except in compliance with the License.
apalmieri 0:7373a1c9d5b4 6 * You may obtain a copy of the License at
apalmieri 0:7373a1c9d5b4 7 *
apalmieri 0:7373a1c9d5b4 8 * http://www.apache.org/licenses/LICENSE-2.0
apalmieri 0:7373a1c9d5b4 9 *
apalmieri 0:7373a1c9d5b4 10 * Unless required by applicable law or agreed to in writing, software
apalmieri 0:7373a1c9d5b4 11 * distributed under the License is distributed on an "AS IS" BASIS,
apalmieri 0:7373a1c9d5b4 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
apalmieri 0:7373a1c9d5b4 13 * See the License for the specific language governing permissions and
apalmieri 0:7373a1c9d5b4 14 * limitations under the License.
apalmieri 0:7373a1c9d5b4 15 */
apalmieri 0:7373a1c9d5b4 16
apalmieri 0:7373a1c9d5b4 17 #include <events/mbed_events.h>
apalmieri 0:7373a1c9d5b4 18 #include "ble/BLE.h"
apalmieri 0:7373a1c9d5b4 19 #include "ble/Gap.h"
apalmieri 0:7373a1c9d5b4 20 #include "pretty_printer.h"
apalmieri 0:7373a1c9d5b4 21
apalmieri 0:7373a1c9d5b4 22 const static char DEVICE_NAME[] = "BATTERY";
apalmieri 0:7373a1c9d5b4 23
apalmieri 0:7373a1c9d5b4 24 using namespace std::literals::chrono_literals;
apalmieri 0:7373a1c9d5b4 25
apalmieri 0:7373a1c9d5b4 26 static events::EventQueue event_queue(/* event count */ 16 * EVENTS_EVENT_SIZE);
apalmieri 0:7373a1c9d5b4 27
apalmieri 0:7373a1c9d5b4 28 class BatteryDemo : ble::Gap::EventHandler {
apalmieri 0:7373a1c9d5b4 29 public:
apalmieri 0:7373a1c9d5b4 30 BatteryDemo(BLE &ble, events::EventQueue &event_queue) :
apalmieri 0:7373a1c9d5b4 31 _ble(ble),
apalmieri 0:7373a1c9d5b4 32 _event_queue(event_queue),
apalmieri 0:7373a1c9d5b4 33 _battery_level(50),
apalmieri 0:7373a1c9d5b4 34 _adv_data_builder(_adv_buffer)
apalmieri 0:7373a1c9d5b4 35 {
apalmieri 0:7373a1c9d5b4 36 }
apalmieri 0:7373a1c9d5b4 37
apalmieri 0:7373a1c9d5b4 38 void start()
apalmieri 0:7373a1c9d5b4 39 {
apalmieri 0:7373a1c9d5b4 40 /* mbed will call on_init_complete when when ble is ready */
apalmieri 0:7373a1c9d5b4 41 _ble.init(this, &BatteryDemo::on_init_complete);
apalmieri 0:7373a1c9d5b4 42
apalmieri 0:7373a1c9d5b4 43 /* this will never return */
apalmieri 0:7373a1c9d5b4 44 _event_queue.dispatch_forever();
apalmieri 0:7373a1c9d5b4 45 }
apalmieri 0:7373a1c9d5b4 46
apalmieri 0:7373a1c9d5b4 47 private:
apalmieri 0:7373a1c9d5b4 48 /** Callback triggered when the ble initialization process has finished */
apalmieri 0:7373a1c9d5b4 49 void on_init_complete(BLE::InitializationCompleteCallbackContext *params)
apalmieri 0:7373a1c9d5b4 50 {
apalmieri 0:7373a1c9d5b4 51 if (params->error != BLE_ERROR_NONE) {
apalmieri 0:7373a1c9d5b4 52 print_error(params->error, "Ble initialization failed.");
apalmieri 0:7373a1c9d5b4 53 return;
apalmieri 0:7373a1c9d5b4 54 }
apalmieri 0:7373a1c9d5b4 55
apalmieri 0:7373a1c9d5b4 56 print_mac_address();
apalmieri 0:7373a1c9d5b4 57
apalmieri 0:7373a1c9d5b4 58 start_advertising();
apalmieri 0:7373a1c9d5b4 59 }
apalmieri 0:7373a1c9d5b4 60
apalmieri 0:7373a1c9d5b4 61 void start_advertising()
apalmieri 0:7373a1c9d5b4 62 {
apalmieri 0:7373a1c9d5b4 63 /* create advertising parameters and payload */
apalmieri 0:7373a1c9d5b4 64
apalmieri 0:7373a1c9d5b4 65 ble::AdvertisingParameters adv_parameters(
apalmieri 0:7373a1c9d5b4 66 /* you cannot connect to this device, you can only read its advertising data,
apalmieri 0:7373a1c9d5b4 67 * scannable means that the device has extra advertising data that the peer can receive if it
apalmieri 0:7373a1c9d5b4 68 * "scans" it which means it is using active scanning (it sends a scan request) */
apalmieri 0:7373a1c9d5b4 69 ble::advertising_type_t::SCANNABLE_UNDIRECTED,
apalmieri 0:7373a1c9d5b4 70 ble::adv_interval_t(ble::millisecond_t(1000))
apalmieri 0:7373a1c9d5b4 71 );
apalmieri 0:7373a1c9d5b4 72
apalmieri 0:7373a1c9d5b4 73 _adv_data_builder.setFlags();
apalmieri 0:7373a1c9d5b4 74 _adv_data_builder.setName(DEVICE_NAME);
apalmieri 0:7373a1c9d5b4 75
apalmieri 0:7373a1c9d5b4 76 /* we add the battery level as part of the payload so it's visible to any device that scans */
apalmieri 0:7373a1c9d5b4 77 _adv_data_builder.setServiceData(GattService::UUID_BATTERY_SERVICE, {&_battery_level, 1});
apalmieri 0:7373a1c9d5b4 78
apalmieri 0:7373a1c9d5b4 79 /* setup advertising */
apalmieri 0:7373a1c9d5b4 80
apalmieri 0:7373a1c9d5b4 81 ble_error_t error = _ble.gap().setAdvertisingParameters(
apalmieri 0:7373a1c9d5b4 82 ble::LEGACY_ADVERTISING_HANDLE,
apalmieri 0:7373a1c9d5b4 83 adv_parameters
apalmieri 0:7373a1c9d5b4 84 );
apalmieri 0:7373a1c9d5b4 85
apalmieri 0:7373a1c9d5b4 86 if (error) {
apalmieri 0:7373a1c9d5b4 87 print_error(error, "_ble.gap().setAdvertisingParameters() failed");
apalmieri 0:7373a1c9d5b4 88 return;
apalmieri 0:7373a1c9d5b4 89 }
apalmieri 0:7373a1c9d5b4 90
apalmieri 0:7373a1c9d5b4 91 error = _ble.gap().setAdvertisingPayload(
apalmieri 0:7373a1c9d5b4 92 ble::LEGACY_ADVERTISING_HANDLE,
apalmieri 0:7373a1c9d5b4 93 _adv_data_builder.getAdvertisingData()
apalmieri 0:7373a1c9d5b4 94 );
apalmieri 0:7373a1c9d5b4 95
apalmieri 0:7373a1c9d5b4 96 if (error) {
apalmieri 0:7373a1c9d5b4 97 print_error(error, "_ble.gap().setAdvertisingPayload() failed");
apalmieri 0:7373a1c9d5b4 98 return;
apalmieri 0:7373a1c9d5b4 99 }
apalmieri 0:7373a1c9d5b4 100
apalmieri 0:7373a1c9d5b4 101 /* when advertising you can optionally add extra data that is only sent
apalmieri 0:7373a1c9d5b4 102 * if the central requests it by doing active scanning */
apalmieri 0:7373a1c9d5b4 103 _adv_data_builder.clear();
apalmieri 0:7373a1c9d5b4 104 const uint8_t _vendor_specific_data[4] = { 0xAD, 0xDE, 0xBE, 0xEF };
apalmieri 0:7373a1c9d5b4 105 _adv_data_builder.setManufacturerSpecificData(_vendor_specific_data);
apalmieri 0:7373a1c9d5b4 106
apalmieri 0:7373a1c9d5b4 107 _ble.gap().setAdvertisingScanResponse(
apalmieri 0:7373a1c9d5b4 108 ble::LEGACY_ADVERTISING_HANDLE,
apalmieri 0:7373a1c9d5b4 109 _adv_data_builder.getAdvertisingData()
apalmieri 0:7373a1c9d5b4 110 );
apalmieri 0:7373a1c9d5b4 111
apalmieri 0:7373a1c9d5b4 112 /* start advertising */
apalmieri 0:7373a1c9d5b4 113
apalmieri 0:7373a1c9d5b4 114 error = _ble.gap().startAdvertising(ble::LEGACY_ADVERTISING_HANDLE);
apalmieri 0:7373a1c9d5b4 115
apalmieri 0:7373a1c9d5b4 116 if (error) {
apalmieri 0:7373a1c9d5b4 117 print_error(error, "_ble.gap().startAdvertising() failed");
apalmieri 0:7373a1c9d5b4 118 return;
apalmieri 0:7373a1c9d5b4 119 }
apalmieri 0:7373a1c9d5b4 120
apalmieri 0:7373a1c9d5b4 121 /* we simulate battery discharging by updating it every second */
apalmieri 0:7373a1c9d5b4 122 _event_queue.call_every(
apalmieri 0:7373a1c9d5b4 123 1000ms,
apalmieri 0:7373a1c9d5b4 124 [this]() {
apalmieri 0:7373a1c9d5b4 125 update_battery_level();
apalmieri 0:7373a1c9d5b4 126 }
apalmieri 0:7373a1c9d5b4 127 );
apalmieri 0:7373a1c9d5b4 128 }
apalmieri 0:7373a1c9d5b4 129
apalmieri 0:7373a1c9d5b4 130 void update_battery_level()
apalmieri 0:7373a1c9d5b4 131 {
apalmieri 0:7373a1c9d5b4 132 if (_battery_level-- == 10) {
apalmieri 0:7373a1c9d5b4 133 _battery_level = 100;
apalmieri 0:7373a1c9d5b4 134 }
apalmieri 0:7373a1c9d5b4 135
apalmieri 0:7373a1c9d5b4 136 /* update the payload with the new value */
apalmieri 0:7373a1c9d5b4 137 ble_error_t error = _adv_data_builder.setServiceData(GattService::UUID_BATTERY_SERVICE, make_Span(&_battery_level, 1));
apalmieri 0:7373a1c9d5b4 138
apalmieri 0:7373a1c9d5b4 139 if (error) {
apalmieri 0:7373a1c9d5b4 140 print_error(error, "_adv_data_builder.setServiceData() failed");
apalmieri 0:7373a1c9d5b4 141 return;
apalmieri 0:7373a1c9d5b4 142 }
apalmieri 0:7373a1c9d5b4 143
apalmieri 0:7373a1c9d5b4 144 /* set the new payload, we don't need to stop advertising */
apalmieri 0:7373a1c9d5b4 145 error = _ble.gap().setAdvertisingPayload(
apalmieri 0:7373a1c9d5b4 146 ble::LEGACY_ADVERTISING_HANDLE,
apalmieri 0:7373a1c9d5b4 147 _adv_data_builder.getAdvertisingData()
apalmieri 0:7373a1c9d5b4 148 );
apalmieri 0:7373a1c9d5b4 149
apalmieri 0:7373a1c9d5b4 150 if (error) {
apalmieri 0:7373a1c9d5b4 151 print_error(error, "_ble.gap().setAdvertisingPayload() failed");
apalmieri 0:7373a1c9d5b4 152 return;
apalmieri 0:7373a1c9d5b4 153 }
apalmieri 0:7373a1c9d5b4 154 }
apalmieri 0:7373a1c9d5b4 155
apalmieri 0:7373a1c9d5b4 156 private:
apalmieri 0:7373a1c9d5b4 157 BLE &_ble;
apalmieri 0:7373a1c9d5b4 158 events::EventQueue &_event_queue;
apalmieri 0:7373a1c9d5b4 159
apalmieri 0:7373a1c9d5b4 160 uint8_t _battery_level;
apalmieri 0:7373a1c9d5b4 161
apalmieri 0:7373a1c9d5b4 162 uint8_t _adv_buffer[ble::LEGACY_ADVERTISING_MAX_SIZE];
apalmieri 0:7373a1c9d5b4 163 ble::AdvertisingDataBuilder _adv_data_builder;
apalmieri 0:7373a1c9d5b4 164 };
apalmieri 0:7373a1c9d5b4 165
apalmieri 0:7373a1c9d5b4 166 /* Schedule processing of events from the BLE middleware in the event queue. */
apalmieri 0:7373a1c9d5b4 167 void schedule_ble_events(BLE::OnEventsToProcessCallbackContext *context)
apalmieri 0:7373a1c9d5b4 168 {
apalmieri 0:7373a1c9d5b4 169 event_queue.call(Callback<void()>(&context->ble, &BLE::processEvents));
apalmieri 0:7373a1c9d5b4 170 }
apalmieri 0:7373a1c9d5b4 171
apalmieri 0:7373a1c9d5b4 172 int main()
apalmieri 0:7373a1c9d5b4 173 {
apalmieri 0:7373a1c9d5b4 174 BLE &ble = BLE::Instance();
apalmieri 0:7373a1c9d5b4 175 ble.onEventsToProcess(schedule_ble_events);
apalmieri 0:7373a1c9d5b4 176
apalmieri 0:7373a1c9d5b4 177 BatteryDemo demo(ble, event_queue);
apalmieri 0:7373a1c9d5b4 178 demo.start();
apalmieri 0:7373a1c9d5b4 179
apalmieri 0:7373a1c9d5b4 180 return 0;
apalmieri 0:7373a1c9d5b4 181 }