BLE Advertising sample application
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.
Revision 0:7373a1c9d5b4, committed 2021-01-14
- Comitter:
- apalmieri
- Date:
- Thu Jan 14 11:25:30 2021 +0000
- Commit message:
- Initial commit of BLE Advertising example for X-NUCLEO-IDB05A1
Changed in this revision
diff -r 000000000000 -r 7373a1c9d5b4 .gitignore --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/.gitignore Thu Jan 14 11:25:30 2021 +0000 @@ -0,0 +1,4 @@ +.build +.mbed +projectfiles +*.py*
diff -r 000000000000 -r 7373a1c9d5b4 CONTRIBUTING.md --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/CONTRIBUTING.md Thu Jan 14 11:25:30 2021 +0000 @@ -0,0 +1,5 @@ +# Contributing to Mbed OS + +Mbed OS is an open-source, device software platform for the Internet of Things. Contributions are an important part of the platform, and our goal is to make it as simple as possible to become a contributor. + +To encourage productive collaboration, as well as robust, consistent and maintainable code, we have a set of guidelines for [contributing to Mbed OS](https://os.mbed.com/docs/mbed-os/latest/contributing/index.html).
diff -r 000000000000 -r 7373a1c9d5b4 README.md --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/README.md Thu Jan 14 11:25:30 2021 +0000 @@ -0,0 +1,37 @@ +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. + +# Running the application + +## Requirements + +Hardware requirements are in the [main readme](https://github.com/ARMmbed/mbed-os-example-ble/blob/master/README.md). + +## Building instructions + +Building instructions for all samples are in the [main readme](https://github.com/ARMmbed/mbed-os-example-ble/blob/master/README.md). + +## Checking for success + +**Note:** Screens captures depicted below show what is expected from this example if the scanner used is *nRF Connect for Mobile* version 4.0.5. If you encounter any difficulties consider trying another scanner or another version of nRF Connect for Mobile. Alternative scanners may require reference to their manuals. + +1. Build the application and install it on your board as explained in the building instructions. +1. Open the BLE scanner on your phone. +1. Start a scan. + + ![](img/start_scan.png) + + **figure 1** How to start scan using nRF Connect for Mobile 4.0.5 + +1. Find your device; it should be named `BATTERY`. + + ![](img/scan_result.png) + + **figure 2** Scan results using nRF Connect for Mobile 4.0.5 + +1. Click on the entry to see the payload details + + +If you can see the battery level, and if its value is changing, the application is working properly. +
diff -r 000000000000 -r 7373a1c9d5b4 img/scan_result.png Binary file img/scan_result.png has changed
diff -r 000000000000 -r 7373a1c9d5b4 img/start_scan.png Binary file img/start_scan.png has changed
diff -r 000000000000 -r 7373a1c9d5b4 mbed-os-ble-utils.lib --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-os-ble-utils.lib Thu Jan 14 11:25:30 2021 +0000 @@ -0,0 +1,1 @@ +https://github.com/ARMmbed/mbed-os-ble-utils/#5a87e640383b2a1465e19ea6c052f80459314670
diff -r 000000000000 -r 7373a1c9d5b4 mbed-os.lib --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-os.lib Thu Jan 14 11:25:30 2021 +0000 @@ -0,0 +1,1 @@ +https://github.com/ARMmbed/mbed-os/#84d991342a41011fc417aab62c0f5a8832f1d18f
diff -r 000000000000 -r 7373a1c9d5b4 mbed_app.json --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed_app.json Thu Jan 14 11:25:30 2021 +0000 @@ -0,0 +1,23 @@ +{ + "target_overrides": { + "*": { + "platform.stdio-baud-rate": 115200 + }, + "K64F": { + "target.components_add": ["BlueNRG_MS"], + "target.features_add": ["BLE"], + "target.extra_labels_add": ["CORDIO"] + }, + "NUCLEO_F401RE": { + "target.components_add": ["BlueNRG_MS"], + "target.features_add": ["BLE"], + "target.extra_labels_add": ["CORDIO"] + }, + "NRF52840_DK": { + "target.features_add": ["BLE"] + }, + "NRF52_DK": { + "target.features_add": ["BLE"] + } + } +}
diff -r 000000000000 -r 7373a1c9d5b4 resources/official_armmbed_example_badge.png Binary file resources/official_armmbed_example_badge.png has changed
diff -r 000000000000 -r 7373a1c9d5b4 source/main.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/source/main.cpp Thu Jan 14 11:25:30 2021 +0000 @@ -0,0 +1,181 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2019 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include <events/mbed_events.h> +#include "ble/BLE.h" +#include "ble/Gap.h" +#include "pretty_printer.h" + +const static char DEVICE_NAME[] = "BATTERY"; + +using namespace std::literals::chrono_literals; + +static events::EventQueue event_queue(/* event count */ 16 * EVENTS_EVENT_SIZE); + +class BatteryDemo : ble::Gap::EventHandler { +public: + BatteryDemo(BLE &ble, events::EventQueue &event_queue) : + _ble(ble), + _event_queue(event_queue), + _battery_level(50), + _adv_data_builder(_adv_buffer) + { + } + + void start() + { + /* mbed will call on_init_complete when when ble is ready */ + _ble.init(this, &BatteryDemo::on_init_complete); + + /* this will never return */ + _event_queue.dispatch_forever(); + } + +private: + /** Callback triggered when the ble initialization process has finished */ + void on_init_complete(BLE::InitializationCompleteCallbackContext *params) + { + if (params->error != BLE_ERROR_NONE) { + print_error(params->error, "Ble initialization failed."); + return; + } + + print_mac_address(); + + start_advertising(); + } + + void start_advertising() + { + /* create advertising parameters and payload */ + + ble::AdvertisingParameters adv_parameters( + /* you cannot connect to this device, you can only read its advertising data, + * scannable means that the device has extra advertising data that the peer can receive if it + * "scans" it which means it is using active scanning (it sends a scan request) */ + ble::advertising_type_t::SCANNABLE_UNDIRECTED, + ble::adv_interval_t(ble::millisecond_t(1000)) + ); + + _adv_data_builder.setFlags(); + _adv_data_builder.setName(DEVICE_NAME); + + /* we add the battery level as part of the payload so it's visible to any device that scans */ + _adv_data_builder.setServiceData(GattService::UUID_BATTERY_SERVICE, {&_battery_level, 1}); + + /* setup advertising */ + + ble_error_t error = _ble.gap().setAdvertisingParameters( + ble::LEGACY_ADVERTISING_HANDLE, + adv_parameters + ); + + if (error) { + print_error(error, "_ble.gap().setAdvertisingParameters() failed"); + return; + } + + error = _ble.gap().setAdvertisingPayload( + ble::LEGACY_ADVERTISING_HANDLE, + _adv_data_builder.getAdvertisingData() + ); + + if (error) { + print_error(error, "_ble.gap().setAdvertisingPayload() failed"); + return; + } + + /* when advertising you can optionally add extra data that is only sent + * if the central requests it by doing active scanning */ + _adv_data_builder.clear(); + const uint8_t _vendor_specific_data[4] = { 0xAD, 0xDE, 0xBE, 0xEF }; + _adv_data_builder.setManufacturerSpecificData(_vendor_specific_data); + + _ble.gap().setAdvertisingScanResponse( + ble::LEGACY_ADVERTISING_HANDLE, + _adv_data_builder.getAdvertisingData() + ); + + /* start advertising */ + + error = _ble.gap().startAdvertising(ble::LEGACY_ADVERTISING_HANDLE); + + if (error) { + print_error(error, "_ble.gap().startAdvertising() failed"); + return; + } + + /* we simulate battery discharging by updating it every second */ + _event_queue.call_every( + 1000ms, + [this]() { + update_battery_level(); + } + ); + } + + void update_battery_level() + { + if (_battery_level-- == 10) { + _battery_level = 100; + } + + /* update the payload with the new value */ + ble_error_t error = _adv_data_builder.setServiceData(GattService::UUID_BATTERY_SERVICE, make_Span(&_battery_level, 1)); + + if (error) { + print_error(error, "_adv_data_builder.setServiceData() failed"); + return; + } + + /* set the new payload, we don't need to stop advertising */ + error = _ble.gap().setAdvertisingPayload( + ble::LEGACY_ADVERTISING_HANDLE, + _adv_data_builder.getAdvertisingData() + ); + + if (error) { + print_error(error, "_ble.gap().setAdvertisingPayload() failed"); + return; + } + } + +private: + BLE &_ble; + events::EventQueue &_event_queue; + + uint8_t _battery_level; + + uint8_t _adv_buffer[ble::LEGACY_ADVERTISING_MAX_SIZE]; + ble::AdvertisingDataBuilder _adv_data_builder; +}; + +/* Schedule processing of events from the BLE middleware in the event queue. */ +void schedule_ble_events(BLE::OnEventsToProcessCallbackContext *context) +{ + event_queue.call(Callback<void()>(&context->ble, &BLE::processEvents)); +} + +int main() +{ + BLE &ble = BLE::Instance(); + ble.onEventsToProcess(schedule_ble_events); + + BatteryDemo demo(ble, event_queue); + demo.start(); + + return 0; +}