This example demonstrates using the GattClient API to control BLE client devices. The canonical source for this example lives at https://github.com/ARMmbed/mbed-os-example-ble/tree/master/BLE_LEDBlinker
BLE LED Blinker
This example demonstrates using the ``GattClient`` API to control BLE client devices.
The example uses two applications running on two different devices:
- The first device - the central - runs the application ``BLE_LEDBlinker`` from this repository. This application sends an on/off toggle over BLE.
- The second device - the peripheral - runs the application ``BLE_LED`` to respond to the toggle.
The toggle simply turns the LED on the peripheral device on and off.
Running the application
Requirements
Hardware requirements are in the main readme.
This example requires *two* devices.
Building instructions
You will need to build both applications and flash each one to a different board.
Please note: The application BLE_LEDBlinker
in this repository initiate a connection to all ble devices which advertise "LED" as complete local name. By default, the application BLE_LED
advertises "LED" as complete local name. If you change the local name advertised by the application BLE_LED
you should reflect your change in this application by changing the value of the constant PEER_NAME
in main.cpp
.
Tip: You may notice that the application also checks the LED characteristic's UUID; you don't need to change this parameter's value, because it already matches the UUID provided by the second application, BLE_LED
.
Building with mbed CLI
If you'd like to use mbed CLI to build this, then you should refer to the main readme. The instructions here relate to using the developer.mbed.org Online Compiler
In order to build this example in the mbed Online Compiler, first import the example using the ‘Import’ button on the right hand side.
Next, select a platform to build for. This must either be a platform that supports BLE, for example the NRF51-DK, or one of the following:
List of platforms supporting Bluetooth Low Energy
Or you must also add a piece of hardware and the supporting library that includes a Bluetooth Low Energy driver for that hardware, for example the K64F or NUCLEO_F401RE with the X-NUCLEO-IDB05A1
List of components supporting Bluetooth Low Energy.
Once you have selected your platform, compile the example and drag and drop the resulting binary onto your board.
For general instructions on using the mbed Online Compiler, please see the mbed Handbook
Checking for success
- Build both applications and install one on each device, as explained in the building instructions.
- The LED number two of the device running ``BLE_LED`` should blink.
Monitoring the application through a serial port
You can run ``BLE_LEDBlinker`` and see that it works properly by monitoring its serial output.
You need a terminal program to listen to the output through a serial port. You can download one, for example:
- Tera Term for Windows.
- CoolTerm for Mac OS X.
- GNU Screen for Linux.
To see the application's output:
- Check which serial port your device is connected to.
- Run a terminal program with the correct serial port and set the baud rate to 9600. For example, to use GNU Screen, run: ``screen /dev/tty.usbmodem1412 9600``.
- The application should start printing the toggle's value to the terminal.
Note: ``BLE_LEDBlinker`` will not run properly if the ``BLE_LED`` application is not running on a second device. The terminal will show a few print statements, but you will not be able to see the application in full operation.
source/main.cpp@12:059c7b7fb18a, 2016-10-24 (annotated)
- Committer:
- mbed_official
- Date:
- Mon Oct 24 11:15:41 2016 +0100
- Revision:
- 12:059c7b7fb18a
- Parent:
- 4:9a6b0d5ea664
- Child:
- 28:64621b6587e1
Merge pull request #32 from ARMmbed/oob
Sync with mbed OS 5.2 OOB repo
Commit copied from https://github.com/ARMmbed/mbed-os-example-ble
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
Vincent Coubard |
0:86bf1d2040b3 | 1 | /* mbed Microcontroller Library |
Vincent Coubard |
0:86bf1d2040b3 | 2 | * Copyright (c) 2006-2015 ARM Limited |
Vincent Coubard |
0:86bf1d2040b3 | 3 | * |
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0:86bf1d2040b3 | 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
Vincent Coubard |
0:86bf1d2040b3 | 5 | * you may not use this file except in compliance with the License. |
Vincent Coubard |
0:86bf1d2040b3 | 6 | * You may obtain a copy of the License at |
Vincent Coubard |
0:86bf1d2040b3 | 7 | * |
Vincent Coubard |
0:86bf1d2040b3 | 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
Vincent Coubard |
0:86bf1d2040b3 | 9 | * |
Vincent Coubard |
0:86bf1d2040b3 | 10 | * Unless required by applicable law or agreed to in writing, software |
Vincent Coubard |
0:86bf1d2040b3 | 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
Vincent Coubard |
0:86bf1d2040b3 | 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
Vincent Coubard |
0:86bf1d2040b3 | 13 | * See the License for the specific language governing permissions and |
Vincent Coubard |
0:86bf1d2040b3 | 14 | * limitations under the License. |
Vincent Coubard |
0:86bf1d2040b3 | 15 | */ |
Vincent Coubard |
0:86bf1d2040b3 | 16 | |
mbed_official | 12:059c7b7fb18a | 17 | #include <events/mbed_events.h> |
Vincent Coubard |
0:86bf1d2040b3 | 18 | #include <mbed.h> |
Vincent Coubard |
0:86bf1d2040b3 | 19 | #include "ble/BLE.h" |
Vincent Coubard |
0:86bf1d2040b3 | 20 | #include "ble/DiscoveredCharacteristic.h" |
Vincent Coubard |
0:86bf1d2040b3 | 21 | #include "ble/DiscoveredService.h" |
Vincent Coubard |
0:86bf1d2040b3 | 22 | |
Vincent Coubard |
0:86bf1d2040b3 | 23 | DigitalOut alivenessLED(LED1, 1); |
Vincent Coubard |
0:86bf1d2040b3 | 24 | static DiscoveredCharacteristic ledCharacteristic; |
Vincent Coubard |
0:86bf1d2040b3 | 25 | static bool triggerLedCharacteristic; |
Vincent Coubard |
0:86bf1d2040b3 | 26 | static const char PEER_NAME[] = "LED"; |
Vincent Coubard |
0:86bf1d2040b3 | 27 | |
Vincent Coubard |
0:86bf1d2040b3 | 28 | static EventQueue eventQueue( |
Vincent Coubard |
0:86bf1d2040b3 | 29 | /* event count */ 16 * /* event size */ 32 |
Vincent Coubard |
0:86bf1d2040b3 | 30 | ); |
Vincent Coubard |
0:86bf1d2040b3 | 31 | |
Vincent Coubard |
0:86bf1d2040b3 | 32 | void periodicCallback(void) { |
Vincent Coubard |
0:86bf1d2040b3 | 33 | alivenessLED = !alivenessLED; /* Do blinky on LED1 while we're waiting for BLE events */ |
Vincent Coubard |
0:86bf1d2040b3 | 34 | } |
Vincent Coubard |
0:86bf1d2040b3 | 35 | |
Vincent Coubard |
0:86bf1d2040b3 | 36 | void advertisementCallback(const Gap::AdvertisementCallbackParams_t *params) { |
Vincent Coubard |
0:86bf1d2040b3 | 37 | // parse the advertising payload, looking for data type COMPLETE_LOCAL_NAME |
Vincent Coubard |
0:86bf1d2040b3 | 38 | // The advertising payload is a collection of key/value records where |
Vincent Coubard |
0:86bf1d2040b3 | 39 | // byte 0: length of the record excluding this byte |
Vincent Coubard |
0:86bf1d2040b3 | 40 | // byte 1: The key, it is the type of the data |
Vincent Coubard |
0:86bf1d2040b3 | 41 | // byte [2..N] The value. N is equal to byte0 - 1 |
Vincent Coubard |
0:86bf1d2040b3 | 42 | for (uint8_t i = 0; i < params->advertisingDataLen; ++i) { |
Vincent Coubard |
0:86bf1d2040b3 | 43 | |
Vincent Coubard |
0:86bf1d2040b3 | 44 | const uint8_t record_length = params->advertisingData[i]; |
Vincent Coubard |
0:86bf1d2040b3 | 45 | if (record_length == 0) { |
Vincent Coubard |
0:86bf1d2040b3 | 46 | continue; |
Vincent Coubard |
0:86bf1d2040b3 | 47 | } |
Vincent Coubard |
0:86bf1d2040b3 | 48 | const uint8_t type = params->advertisingData[i + 1]; |
Vincent Coubard |
0:86bf1d2040b3 | 49 | const uint8_t* value = params->advertisingData + i + 2; |
Vincent Coubard |
0:86bf1d2040b3 | 50 | const uint8_t value_length = record_length - 1; |
Vincent Coubard |
0:86bf1d2040b3 | 51 | |
Vincent Coubard |
0:86bf1d2040b3 | 52 | if(type == GapAdvertisingData::COMPLETE_LOCAL_NAME) { |
Vincent Coubard |
0:86bf1d2040b3 | 53 | if ((value_length == sizeof(PEER_NAME)) && (memcmp(value, PEER_NAME, value_length) == 0)) { |
Vincent Coubard |
0:86bf1d2040b3 | 54 | printf( |
Vincent Coubard |
0:86bf1d2040b3 | 55 | "adv peerAddr[%02x %02x %02x %02x %02x %02x] rssi %d, isScanResponse %u, AdvertisementType %u\r\n", |
Vincent Coubard |
0:86bf1d2040b3 | 56 | params->peerAddr[5], params->peerAddr[4], params->peerAddr[3], params->peerAddr[2], |
Vincent Coubard |
0:86bf1d2040b3 | 57 | params->peerAddr[1], params->peerAddr[0], params->rssi, params->isScanResponse, params->type |
Vincent Coubard |
0:86bf1d2040b3 | 58 | ); |
Vincent Coubard |
0:86bf1d2040b3 | 59 | BLE::Instance().gap().connect(params->peerAddr, Gap::ADDR_TYPE_RANDOM_STATIC, NULL, NULL); |
Vincent Coubard |
0:86bf1d2040b3 | 60 | break; |
Vincent Coubard |
0:86bf1d2040b3 | 61 | } |
Vincent Coubard |
0:86bf1d2040b3 | 62 | } |
Vincent Coubard |
0:86bf1d2040b3 | 63 | i += record_length; |
Vincent Coubard |
0:86bf1d2040b3 | 64 | } |
Vincent Coubard |
0:86bf1d2040b3 | 65 | } |
Vincent Coubard |
0:86bf1d2040b3 | 66 | |
Vincent Coubard |
0:86bf1d2040b3 | 67 | void serviceDiscoveryCallback(const DiscoveredService *service) { |
Vincent Coubard |
0:86bf1d2040b3 | 68 | if (service->getUUID().shortOrLong() == UUID::UUID_TYPE_SHORT) { |
Vincent Coubard |
0:86bf1d2040b3 | 69 | printf("S UUID-%x attrs[%u %u]\r\n", service->getUUID().getShortUUID(), service->getStartHandle(), service->getEndHandle()); |
Vincent Coubard |
0:86bf1d2040b3 | 70 | } else { |
Vincent Coubard |
0:86bf1d2040b3 | 71 | printf("S UUID-"); |
Vincent Coubard |
0:86bf1d2040b3 | 72 | const uint8_t *longUUIDBytes = service->getUUID().getBaseUUID(); |
Vincent Coubard |
0:86bf1d2040b3 | 73 | for (unsigned i = 0; i < UUID::LENGTH_OF_LONG_UUID; i++) { |
Vincent Coubard |
0:86bf1d2040b3 | 74 | printf("%02x", longUUIDBytes[i]); |
Vincent Coubard |
0:86bf1d2040b3 | 75 | } |
Vincent Coubard |
0:86bf1d2040b3 | 76 | printf(" attrs[%u %u]\r\n", service->getStartHandle(), service->getEndHandle()); |
Vincent Coubard |
0:86bf1d2040b3 | 77 | } |
Vincent Coubard |
0:86bf1d2040b3 | 78 | } |
Vincent Coubard |
0:86bf1d2040b3 | 79 | |
Vincent Coubard |
0:86bf1d2040b3 | 80 | void updateLedCharacteristic(void) { |
Vincent Coubard |
0:86bf1d2040b3 | 81 | if (!BLE::Instance().gattClient().isServiceDiscoveryActive()) { |
Vincent Coubard |
0:86bf1d2040b3 | 82 | ledCharacteristic.read(); |
Vincent Coubard |
0:86bf1d2040b3 | 83 | } |
Vincent Coubard |
0:86bf1d2040b3 | 84 | } |
Vincent Coubard |
0:86bf1d2040b3 | 85 | |
Vincent Coubard |
0:86bf1d2040b3 | 86 | void characteristicDiscoveryCallback(const DiscoveredCharacteristic *characteristicP) { |
Vincent Coubard |
0:86bf1d2040b3 | 87 | printf(" C UUID-%x valueAttr[%u] props[%x]\r\n", characteristicP->getUUID().getShortUUID(), characteristicP->getValueHandle(), (uint8_t)characteristicP->getProperties().broadcast()); |
Vincent Coubard |
0:86bf1d2040b3 | 88 | if (characteristicP->getUUID().getShortUUID() == 0xa001) { /* !ALERT! Alter this filter to suit your device. */ |
Vincent Coubard |
0:86bf1d2040b3 | 89 | ledCharacteristic = *characteristicP; |
Vincent Coubard |
0:86bf1d2040b3 | 90 | triggerLedCharacteristic = true; |
Vincent Coubard |
0:86bf1d2040b3 | 91 | } |
Vincent Coubard |
0:86bf1d2040b3 | 92 | } |
Vincent Coubard |
0:86bf1d2040b3 | 93 | |
Vincent Coubard |
0:86bf1d2040b3 | 94 | void discoveryTerminationCallback(Gap::Handle_t connectionHandle) { |
Vincent Coubard |
0:86bf1d2040b3 | 95 | printf("terminated SD for handle %u\r\n", connectionHandle); |
Vincent Coubard |
0:86bf1d2040b3 | 96 | if (triggerLedCharacteristic) { |
Vincent Coubard |
0:86bf1d2040b3 | 97 | triggerLedCharacteristic = false; |
mbed_official | 12:059c7b7fb18a | 98 | eventQueue.call(updateLedCharacteristic); |
Vincent Coubard |
0:86bf1d2040b3 | 99 | } |
Vincent Coubard |
0:86bf1d2040b3 | 100 | } |
Vincent Coubard |
0:86bf1d2040b3 | 101 | |
Vincent Coubard |
0:86bf1d2040b3 | 102 | void connectionCallback(const Gap::ConnectionCallbackParams_t *params) { |
Vincent Coubard |
0:86bf1d2040b3 | 103 | if (params->role == Gap::CENTRAL) { |
Vincent Coubard |
0:86bf1d2040b3 | 104 | BLE &ble = BLE::Instance(); |
Vincent Coubard |
0:86bf1d2040b3 | 105 | ble.gattClient().onServiceDiscoveryTermination(discoveryTerminationCallback); |
Vincent Coubard |
0:86bf1d2040b3 | 106 | ble.gattClient().launchServiceDiscovery(params->handle, serviceDiscoveryCallback, characteristicDiscoveryCallback, 0xa000, 0xa001); |
Vincent Coubard |
0:86bf1d2040b3 | 107 | } |
Vincent Coubard |
0:86bf1d2040b3 | 108 | } |
Vincent Coubard |
0:86bf1d2040b3 | 109 | |
Vincent Coubard |
0:86bf1d2040b3 | 110 | void triggerToggledWrite(const GattReadCallbackParams *response) { |
Vincent Coubard |
0:86bf1d2040b3 | 111 | if (response->handle == ledCharacteristic.getValueHandle()) { |
Vincent Coubard |
0:86bf1d2040b3 | 112 | printf("triggerToggledWrite: handle %u, offset %u, len %u\r\n", response->handle, response->offset, response->len); |
Vincent Coubard |
0:86bf1d2040b3 | 113 | for (unsigned index = 0; index < response->len; index++) { |
Vincent Coubard |
0:86bf1d2040b3 | 114 | printf("%c[%02x]", response->data[index], response->data[index]); |
Vincent Coubard |
0:86bf1d2040b3 | 115 | } |
Vincent Coubard |
0:86bf1d2040b3 | 116 | printf("\r\n"); |
Vincent Coubard |
0:86bf1d2040b3 | 117 | |
Vincent Coubard |
0:86bf1d2040b3 | 118 | uint8_t toggledValue = response->data[0] ^ 0x1; |
Vincent Coubard |
0:86bf1d2040b3 | 119 | ledCharacteristic.write(1, &toggledValue); |
Vincent Coubard |
0:86bf1d2040b3 | 120 | } |
Vincent Coubard |
0:86bf1d2040b3 | 121 | } |
Vincent Coubard |
0:86bf1d2040b3 | 122 | |
Vincent Coubard |
0:86bf1d2040b3 | 123 | void triggerRead(const GattWriteCallbackParams *response) { |
Vincent Coubard |
0:86bf1d2040b3 | 124 | if (response->handle == ledCharacteristic.getValueHandle()) { |
Vincent Coubard |
0:86bf1d2040b3 | 125 | ledCharacteristic.read(); |
Vincent Coubard |
0:86bf1d2040b3 | 126 | } |
Vincent Coubard |
0:86bf1d2040b3 | 127 | } |
Vincent Coubard |
0:86bf1d2040b3 | 128 | |
Vincent Coubard |
0:86bf1d2040b3 | 129 | void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *) { |
Vincent Coubard |
0:86bf1d2040b3 | 130 | printf("disconnected\r\n"); |
Vincent Coubard |
0:86bf1d2040b3 | 131 | /* Start scanning and try to connect again */ |
Vincent Coubard |
0:86bf1d2040b3 | 132 | BLE::Instance().gap().startScan(advertisementCallback); |
Vincent Coubard |
0:86bf1d2040b3 | 133 | } |
Vincent Coubard |
0:86bf1d2040b3 | 134 | |
Vincent Coubard |
0:86bf1d2040b3 | 135 | void onBleInitError(BLE &ble, ble_error_t error) |
Vincent Coubard |
0:86bf1d2040b3 | 136 | { |
Vincent Coubard |
0:86bf1d2040b3 | 137 | /* Initialization error handling should go here */ |
Vincent Coubard |
0:86bf1d2040b3 | 138 | } |
Vincent Coubard |
0:86bf1d2040b3 | 139 | |
Vincent Coubard |
0:86bf1d2040b3 | 140 | void bleInitComplete(BLE::InitializationCompleteCallbackContext *params) |
Vincent Coubard |
0:86bf1d2040b3 | 141 | { |
Vincent Coubard |
0:86bf1d2040b3 | 142 | BLE& ble = params->ble; |
Vincent Coubard |
0:86bf1d2040b3 | 143 | ble_error_t error = params->error; |
Vincent Coubard |
0:86bf1d2040b3 | 144 | |
Vincent Coubard |
0:86bf1d2040b3 | 145 | if (error != BLE_ERROR_NONE) { |
Vincent Coubard |
0:86bf1d2040b3 | 146 | /* In case of error, forward the error handling to onBleInitError */ |
Vincent Coubard |
0:86bf1d2040b3 | 147 | onBleInitError(ble, error); |
Vincent Coubard |
0:86bf1d2040b3 | 148 | return; |
Vincent Coubard |
0:86bf1d2040b3 | 149 | } |
Vincent Coubard |
0:86bf1d2040b3 | 150 | |
Vincent Coubard |
0:86bf1d2040b3 | 151 | /* Ensure that it is the default instance of BLE */ |
Vincent Coubard |
0:86bf1d2040b3 | 152 | if (ble.getInstanceID() != BLE::DEFAULT_INSTANCE) { |
Vincent Coubard |
0:86bf1d2040b3 | 153 | return; |
Vincent Coubard |
0:86bf1d2040b3 | 154 | } |
Vincent Coubard |
0:86bf1d2040b3 | 155 | |
Vincent Coubard |
0:86bf1d2040b3 | 156 | ble.gap().onDisconnection(disconnectionCallback); |
Vincent Coubard |
0:86bf1d2040b3 | 157 | ble.gap().onConnection(connectionCallback); |
Vincent Coubard |
0:86bf1d2040b3 | 158 | |
Vincent Coubard |
0:86bf1d2040b3 | 159 | ble.gattClient().onDataRead(triggerToggledWrite); |
Vincent Coubard |
0:86bf1d2040b3 | 160 | ble.gattClient().onDataWrite(triggerRead); |
Vincent Coubard |
0:86bf1d2040b3 | 161 | |
Vincent Coubard |
0:86bf1d2040b3 | 162 | // scan interval: 400ms and scan window: 400ms. |
Vincent Coubard |
0:86bf1d2040b3 | 163 | // Every 400ms the device will scan for 400ms |
Vincent Coubard |
0:86bf1d2040b3 | 164 | // This means that the device will scan continuously. |
Vincent Coubard |
0:86bf1d2040b3 | 165 | ble.gap().setScanParams(400, 400); |
Vincent Coubard |
0:86bf1d2040b3 | 166 | ble.gap().startScan(advertisementCallback); |
Vincent Coubard |
0:86bf1d2040b3 | 167 | } |
Vincent Coubard |
0:86bf1d2040b3 | 168 | |
Vincent Coubard |
0:86bf1d2040b3 | 169 | void scheduleBleEventsProcessing(BLE::OnEventsToProcessCallbackContext* context) { |
Vincent Coubard |
0:86bf1d2040b3 | 170 | BLE &ble = BLE::Instance(); |
mbed_official | 12:059c7b7fb18a | 171 | eventQueue.call(Callback<void()>(&ble, &BLE::processEvents)); |
Vincent Coubard |
0:86bf1d2040b3 | 172 | } |
Vincent Coubard |
0:86bf1d2040b3 | 173 | |
Vincent Coubard |
0:86bf1d2040b3 | 174 | int main() |
Vincent Coubard |
0:86bf1d2040b3 | 175 | { |
Vincent Coubard |
0:86bf1d2040b3 | 176 | triggerLedCharacteristic = false; |
mbed_official | 12:059c7b7fb18a | 177 | eventQueue.call_every(500, periodicCallback); |
Vincent Coubard |
0:86bf1d2040b3 | 178 | |
Vincent Coubard |
0:86bf1d2040b3 | 179 | BLE &ble = BLE::Instance(); |
Vincent Coubard |
0:86bf1d2040b3 | 180 | ble.onEventsToProcess(scheduleBleEventsProcessing); |
Vincent Coubard |
0:86bf1d2040b3 | 181 | ble.init(bleInitComplete); |
Vincent Coubard |
0:86bf1d2040b3 | 182 | |
mbed_official | 12:059c7b7fb18a | 183 | eventQueue.dispatch_forever(); |
Vincent Coubard |
0:86bf1d2040b3 | 184 | |
Vincent Coubard |
0:86bf1d2040b3 | 185 | return 0; |
Vincent Coubard |
0:86bf1d2040b3 | 186 | } |