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| 1 | +/* mbed Microcontroller Library |
| 2 | + * Copyright (c) 2006-2019 ARM Limited |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +#include <events/mbed_events.h> |
| 18 | +#include "ble/BLE.h" |
| 19 | +#include "ble/Gap.h" |
| 20 | +#include "pretty_printer.h" |
| 21 | +#include "mbed-trace/mbed_trace.h" |
| 22 | + |
| 23 | +const static char DEVICE_NAME[] = "BATTERY"; |
| 24 | + |
| 25 | +using namespace std::literals::chrono_literals; |
| 26 | + |
| 27 | +static events::EventQueue event_queue(/* event count */ 16 * EVENTS_EVENT_SIZE); |
| 28 | + |
| 29 | +class BatteryDemo : ble::Gap::EventHandler { |
| 30 | +public: |
| 31 | + BatteryDemo(BLE &ble, events::EventQueue &event_queue) : |
| 32 | + _ble(ble), |
| 33 | + _event_queue(event_queue), |
| 34 | + _battery_level(50), |
| 35 | + _adv_data_builder(_adv_buffer) |
| 36 | + { |
| 37 | + } |
| 38 | + |
| 39 | + void start() |
| 40 | + { |
| 41 | + /* mbed will call on_init_complete when when ble is ready */ |
| 42 | + _ble.init(this, &BatteryDemo::on_init_complete); |
| 43 | + |
| 44 | + /* this will never return */ |
| 45 | + _event_queue.dispatch_forever(); |
| 46 | + } |
| 47 | + |
| 48 | +private: |
| 49 | + /** Callback triggered when the ble initialization process has finished */ |
| 50 | + void on_init_complete(BLE::InitializationCompleteCallbackContext *params) |
| 51 | + { |
| 52 | + if (params->error != BLE_ERROR_NONE) { |
| 53 | + print_error(params->error, "Ble initialization failed."); |
| 54 | + return; |
| 55 | + } |
| 56 | + |
| 57 | + print_mac_address(); |
| 58 | + |
| 59 | + start_advertising(); |
| 60 | + } |
| 61 | + |
| 62 | + void start_advertising() |
| 63 | + { |
| 64 | + /* create advertising parameters and payload */ |
| 65 | + |
| 66 | + ble::AdvertisingParameters adv_parameters( |
| 67 | + /* you cannot connect to this device, you can only read its advertising data, |
| 68 | + * scannable means that the device has extra advertising data that the peer can receive if it |
| 69 | + * "scans" it which means it is using active scanning (it sends a scan request) */ |
| 70 | + ble::advertising_type_t::SCANNABLE_UNDIRECTED, |
| 71 | + ble::adv_interval_t(ble::millisecond_t(1000)) |
| 72 | + ); |
| 73 | + |
| 74 | + /* when advertising you can optionally add extra data that is only sent |
| 75 | + * if the central requests it by doing active scanning (sending scan requests), |
| 76 | + * in this example we set this payload first because we want to later reuse |
| 77 | + * the same _adv_data_builder builder for payload updates */ |
| 78 | + |
| 79 | + const uint8_t _vendor_specific_data[4] = { 0xAD, 0xDE, 0xBE, 0xEF }; |
| 80 | + _adv_data_builder.setManufacturerSpecificData(_vendor_specific_data); |
| 81 | + |
| 82 | + _ble.gap().setAdvertisingScanResponse( |
| 83 | + ble::LEGACY_ADVERTISING_HANDLE, |
| 84 | + _adv_data_builder.getAdvertisingData() |
| 85 | + ); |
| 86 | + |
| 87 | + /* now we set the advertising payload that gets sent during advertising without any scan requests */ |
| 88 | + |
| 89 | + _adv_data_builder.clear(); |
| 90 | + _adv_data_builder.setFlags(); |
| 91 | + _adv_data_builder.setName(DEVICE_NAME); |
| 92 | + |
| 93 | + /* we add the battery level as part of the payload so it's visible to any device that scans, |
| 94 | + * this part of the payload will be updated periodically without affecting the rest of the payload */ |
| 95 | + _adv_data_builder.setServiceData(GattService::UUID_BATTERY_SERVICE, {&_battery_level, 1}); |
| 96 | + |
| 97 | + /* setup advertising */ |
| 98 | + |
| 99 | + ble_error_t error = _ble.gap().setAdvertisingParameters( |
| 100 | + ble::LEGACY_ADVERTISING_HANDLE, |
| 101 | + adv_parameters |
| 102 | + ); |
| 103 | + |
| 104 | + if (error) { |
| 105 | + print_error(error, "_ble.gap().setAdvertisingParameters() failed"); |
| 106 | + return; |
| 107 | + } |
| 108 | + |
| 109 | + error = _ble.gap().setAdvertisingPayload( |
| 110 | + ble::LEGACY_ADVERTISING_HANDLE, |
| 111 | + _adv_data_builder.getAdvertisingData() |
| 112 | + ); |
| 113 | + |
| 114 | + if (error) { |
| 115 | + print_error(error, "_ble.gap().setAdvertisingPayload() failed"); |
| 116 | + return; |
| 117 | + } |
| 118 | + |
| 119 | + /* start advertising */ |
| 120 | + |
| 121 | + error = _ble.gap().startAdvertising(ble::LEGACY_ADVERTISING_HANDLE); |
| 122 | + |
| 123 | + if (error) { |
| 124 | + print_error(error, "_ble.gap().startAdvertising() failed"); |
| 125 | + return; |
| 126 | + } |
| 127 | + |
| 128 | + /* we simulate battery discharging by updating it every second */ |
| 129 | + _event_queue.call_every( |
| 130 | + 1000ms, |
| 131 | + [this]() { |
| 132 | + update_battery_level(); |
| 133 | + } |
| 134 | + ); |
| 135 | + } |
| 136 | + |
| 137 | + void update_battery_level() |
| 138 | + { |
| 139 | + if (_battery_level-- == 10) { |
| 140 | + _battery_level = 100; |
| 141 | + } |
| 142 | + |
| 143 | + /* update the payload with the new value of the bettery level, the rest of the payload remains the same */ |
| 144 | + ble_error_t error = _adv_data_builder.setServiceData(GattService::UUID_BATTERY_SERVICE, make_Span(&_battery_level, 1)); |
| 145 | + |
| 146 | + if (error) { |
| 147 | + print_error(error, "_adv_data_builder.setServiceData() failed"); |
| 148 | + return; |
| 149 | + } |
| 150 | + |
| 151 | + /* set the new payload, we don't need to stop advertising */ |
| 152 | + error = _ble.gap().setAdvertisingPayload( |
| 153 | + ble::LEGACY_ADVERTISING_HANDLE, |
| 154 | + _adv_data_builder.getAdvertisingData() |
| 155 | + ); |
| 156 | + |
| 157 | + if (error) { |
| 158 | + print_error(error, "_ble.gap().setAdvertisingPayload() failed"); |
| 159 | + return; |
| 160 | + } |
| 161 | + } |
| 162 | + |
| 163 | +private: |
| 164 | + BLE &_ble; |
| 165 | + events::EventQueue &_event_queue; |
| 166 | + |
| 167 | + uint8_t _battery_level; |
| 168 | + |
| 169 | + uint8_t _adv_buffer[ble::LEGACY_ADVERTISING_MAX_SIZE]; |
| 170 | + ble::AdvertisingDataBuilder _adv_data_builder; |
| 171 | +}; |
| 172 | + |
| 173 | +/* Schedule processing of events from the BLE middleware in the event queue. */ |
| 174 | +void schedule_ble_events(BLE::OnEventsToProcessCallbackContext *context) |
| 175 | +{ |
| 176 | + event_queue.call(Callback<void()>(&context->ble, &BLE::processEvents)); |
| 177 | +} |
| 178 | + |
| 179 | +int main() |
| 180 | +{ |
| 181 | + mbed_trace_init(); |
| 182 | + |
| 183 | + BLE &ble = BLE::Instance(); |
| 184 | + ble.onEventsToProcess(schedule_ble_events); |
| 185 | + |
| 186 | + BatteryDemo demo(ble, event_queue); |
| 187 | + demo.start(); |
| 188 | + |
| 189 | + return 0; |
| 190 | +} |
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