Mbed OS 文档翻译 之 参考(API(蓝牙(BLE)))

BLE

蓝牙低功耗(BLE)是用于构建个人区域网络的低功率无线技术标准。BLE 的典型应用是医疗保健,健身追踪器,信标,智能家居,安全,娱乐,接近传感器,工业和汽车。

Arm Mbed BLE,也称为 BLE_API,是 Mbed 的蓝牙低功耗软件解决方案。许多 Mbed 目标和组件支持 Mbed BLE。开发人员可以使用它来创建新的支持 BLE 的应用程序。

Mbed 的 BLE_API 与平台上的 BLE 控制器接口。它隐藏了 BLE 堆栈在 C++ 抽象背后的复杂性,并且与所有支持 BLE 的 Mbed 平台兼容。Mbed OS BLE_API 自动配置时钟,定时器和其他硬件外设,以最低功耗工作。

BLE_API,桥接和栈

                                                Mbed OS 文档翻译 之 参考(API(蓝牙(BLE)))_第1张图片

您可以使用 Mbed OS,BLE_API 和控制器特定的蓝牙栈以及一些桥接软件构建 BLE 应用程序,以使其适应 BLE_API:

  • BLE_API 如上所述。
  • 桥接软件特定于每个供应商的平台。它为 BLE_API 提供的接口提供实例化,并帮助驱动底层控制器和蓝牙栈。
  • 蓝牙栈实现蓝牙协议并且特定于控制器,因此使用不同控制器的供应商可以提供不同的栈。

在 BLE_API 里面

Mbed OS 文档翻译 之 参考(API(蓝牙(BLE)))_第2张图片

BLE_API 提供构建块来帮助构建应用程序。这些分为两大类:

  1. 在 ble/表达 BLE 结构的接口,例如 GAP,GATT,服务和特性。

  2. ble/services 下的类为许多常用的 GATT 配置文件提供参考实现。'services/' 下的代码不是必需的,但它是原型设计的有用起点。我们继续实施标准的 GATT 配置文件。

BLEDevice 类和头文件

Mbed 的 BLE_API 的入口点是使用标题 ble/BLE.h 可访问的 BLE 类。此类允许您获取 BLE 对象,该对象包含规范兼容的 BLE 设备的基本属性,并且可以与任何 BLE 无线电一起使用:

#include "ble/BLE.h"

BLE& mydevicename = BLE::Instance();

该类的成员函数可以按目的划分:

  1. 基本 BLE 操作,例如初始化控制器。

  2. 管理 GAP,GATT 或安全性的蓝牙模块的访问者。

用法

  1. 设置广告和连接模式。
  2. 将 UUID 分配给服务及其特性。
  3. 创建输入特征。
  4. 构造一个服务类并将其添加到 BLE 栈。
  5. 特征值更改时推送通知。

BLE 类参考

BLE 类参考

数据结构
struct   InitializationCompleteCallbackContext
struct   OnEventsToProcessCallbackContext
公共类型
typedef unsigned  InstanceID_t
typedef FunctionPointerWithContext< OnEventsToProcessCallbackContext * >  OnEventsToProcessCallback_t
typedef void(*  InitializationCompleteCallback_t) (InitializationCompleteCallbackContext *context)
公共成员函数
InstanceID_t  getInstanceID (void) const
void  onEventsToProcess (const OnEventsToProcessCallback_t &on_event_cb)
void  processEvents ()
ble_error_t  init (InitializationCompleteCallback_t completion_cb=NULL)
template
ble_error_t  init (T *object, void(T::*completion_cb)(InitializationCompleteCallbackContext *context))
bool  hasInitialized (void) const
ble_error_t  shutdown (void)
const char *  getVersion (void)
Gap &  gap ()
const Gap &  gap () const
GattServer &  gattServer ()
const GattServer &  gattServer () const
GattClient &  gattClient ()
const GattClient &  gattClient () const
SecurityManager &  securityManager ()
const SecurityManager &  securityManager () const
  BLE (InstanceID_t instanceID=DEFAULT_INSTANCE)
void  waitForEvent (void)
ble_error_t  setAddress (BLEProtocol::AddressType_t type, const BLEProtocol::AddressBytes_t address)
ble_error_t  getAddress (BLEProtocol::AddressType_t *typeP, BLEProtocol::AddressBytes_t address)
void  setAdvertisingType (GapAdvertisingParams::AdvertisingType advType)
void  setAdvertisingInterval (uint16_t interval)
uint16_t  getMinAdvertisingInterval (void) const
uint16_t  getMinNonConnectableAdvertisingInterval (void) const
uint16_t  getMaxAdvertisingInterval (void) const
void  setAdvertisingTimeout (uint16_t timeout)
void  setAdvertisingParams (const GapAdvertisingParams &advParams)
const GapAdvertisingParams &  getAdvertisingParams (void) const
ble_error_t  accumulateAdvertisingPayload (uint8_t flags)
ble_error_t  accumulateAdvertisingPayload (GapAdvertisingData::Appearance app)
ble_error_t  accumulateAdvertisingPayloadTxPower (int8_t power)
ble_error_t  accumulateAdvertisingPayload (GapAdvertisingData::DataType type, const uint8_t *data, uint8_t len)
ble_error_t  setAdvertisingData (const GapAdvertisingData &advData)
const GapAdvertisingData &  getAdvertisingData (void) const
void  clearAdvertisingPayload (void)
ble_error_t  setAdvertisingPayload (void)
ble_error_t  accumulateScanResponse (GapAdvertisingData::DataType type, const uint8_t *data, uint8_t len)
void  clearScanResponse (void)
ble_error_t  startAdvertising (void)
ble_error_t  stopAdvertising (void)
ble_error_t  setScanParams (uint16_t interval=GapScanningParams::SCAN_INTERVAL_MAX, uint16_t window=GapScanningParams::SCAN_WINDOW_MAX, uint16_t timeout=0, bool activeScanning=false)
ble_error_t  setScanInterval (uint16_t interval)
ble_error_t  setScanWindow (uint16_t window)
ble_error_t  setScanTimeout (uint16_t timeout)
void  setActiveScan (bool activeScanning)
ble_error_t  startScan (void(*callback)(const Gap::AdvertisementCallbackParams_t *params))
template
ble_error_t  startScan (T *object, void(T::*memberCallback)(const Gap::AdvertisementCallbackParams_t *params))
ble_error_t  stopScan (void)
ble_error_t  connect (const BLEProtocol::AddressBytes_t peerAddr, BLEProtocol::AddressType_t peerAddrType=BLEProtocol::AddressType::RANDOM_STATIC, const Gap::ConnectionParams_t *connectionParams=NULL, const GapScanningParams *scanParams=NULL)
ble_error_t  disconnect (Gap::Handle_t connectionHandle, Gap::DisconnectionReason_t reason)
ble_error_t  disconnect (Gap::DisconnectionReason_t reason)
Gap::GapState_t  getGapState (void) const
ble_error_t  getPreferredConnectionParams (Gap::ConnectionParams_t *params)
ble_error_t  setPreferredConnectionParams (const Gap::ConnectionParams_t *params)
ble_error_t  updateConnectionParams (Gap::Handle_t handle, const Gap::ConnectionParams_t *params)
ble_error_t  setDeviceName (const uint8_t *deviceName)
ble_error_t  getDeviceName (uint8_t *deviceName, unsigned *lengthP)
ble_error_t  setAppearance (GapAdvertisingData::Appearance appearance)
ble_error_t  getAppearance (GapAdvertisingData::Appearance *appearanceP)
ble_error_t  setTxPower (int8_t txPower)
void  getPermittedTxPowerValues (const int8_t **valueArrayPP, size_t *countP)
ble_error_t  addService (GattService &service)
ble_error_t  readCharacteristicValue (GattAttribute::Handle_t attributeHandle, uint8_t *buffer, uint16_t *lengthP)
ble_error_t  readCharacteristicValue (Gap::Handle_t connectionHandle, GattAttribute::Handle_t attributeHandle, uint8_t *buffer, uint16_t *lengthP)
ble_error_t  updateCharacteristicValue (GattAttribute::Handle_t attributeHandle, const uint8_t *value, uint16_t size, bool localOnly=false)
ble_error_t  updateCharacteristicValue (Gap::Handle_t connectionHandle, GattAttribute::Handle_t attributeHandle, const uint8_t *value, uint16_t size, bool localOnly=false)
ble_error_t  initializeSecurity (bool enableBonding=true, bool requireMITM=true, SecurityManager::SecurityIOCapabilities_t iocaps=SecurityManager::IO_CAPS_NONE, const SecurityManager::Passkey_t passkey=NULL)
ble_error_t  getLinkSecurity (Gap::Handle_t connectionHandle, SecurityManager::LinkSecurityStatus_t *securityStatusP)
ble_error_t  purgeAllBondingState (void)
void  onTimeout (Gap::TimeoutEventCallback_t timeoutCallback)
void  onConnection (Gap::ConnectionEventCallback_t connectionCallback)
void  onDisconnection (Gap::DisconnectionEventCallback_t disconnectionCallback)
template
void  onDisconnection (T *tptr, void(T::*mptr)(const Gap::DisconnectionCallbackParams_t *))
void  onRadioNotification (void(*callback)(bool))
void  onDataSent (void(*callback)(unsigned count))
template
void  onDataSent (T *objPtr, void(T::*memberPtr)(unsigned count))
void  onDataWritten (void(*callback)(const GattWriteCallbackParams *eventDataP))
template
void  onDataWritten (T *objPtr, void(T::*memberPtr)(const GattWriteCallbackParams *context))
ble_error_t  onDataRead (void(*callback)(const GattReadCallbackParams *eventDataP))
template
ble_error_t  onDataRead (T *objPtr, void(T::*memberPtr)(const GattReadCallbackParams *context))
void  onUpdatesEnabled (GattServer::EventCallback_t callback)
void  onUpdatesDisabled (GattServer::EventCallback_t callback)
void  onConfirmationReceived (GattServer::EventCallback_t callback)
void  onSecuritySetupInitiated (SecurityManager::SecuritySetupInitiatedCallback_t callback)
void  onSecuritySetupCompleted (SecurityManager::SecuritySetupCompletedCallback_t callback)
void  onLinkSecured (SecurityManager::LinkSecuredCallback_t callback)
void  onSecurityContextStored (SecurityManager::HandleSpecificEvent_t callback)
void  onPasskeyDisplay (SecurityManager::PasskeyDisplayCallback_t callback)
静态公共成员函数
static BLE &  Instance (InstanceID_t id=DEFAULT_INSTANCE)
static const char *  errorToString (ble_error_t error)
Static Public Attributes
static const InstanceID_t  DEFAULT_INSTANCE = 0
static const InstanceID_t  NUM_INSTANCES = 1
Friends
class  BLEInstanceBase

示例:BLE 信标

这是一个演示如何创建 BLE 信标的示例。

main.cpp                                                                                                                                                 导入到 Mbed IDE

/* mbed Microcontroller Library
 * Copyright (c) 2006-2015 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 
#include 
#include "ble/BLE.h"
#include "ble/services/iBeacon.h"

static iBeacon* ibeaconPtr;

static EventQueue eventQueue(/* event count */ 4 * EVENTS_EVENT_SIZE);

/**
 * This function is called when the ble initialization process has failled
 */
void onBleInitError(BLE &ble, ble_error_t error)
{
    /* Initialization error handling should go here */
}

/**
 * Callback triggered when the ble initialization process has finished
 */
void bleInitComplete(BLE::InitializationCompleteCallbackContext *params)
{
    BLE&        ble   = params->ble;
    ble_error_t error = params->error;

    if (error != BLE_ERROR_NONE) {
        /* In case of error, forward the error handling to onBleInitError */
        onBleInitError(ble, error);
        return;
    }

    /* Ensure that it is the default instance of BLE */
    if(ble.getInstanceID() != BLE::DEFAULT_INSTANCE) {
        return;
    }

    /**
     * The Beacon payload has the following composition:
     * 128-Bit / 16byte UUID = E2 0A 39 F4 73 F5 4B C4 A1 2F 17 D1 AD 07 A9 61
     * Major/Minor  = 0x1122 / 0x3344
     * Tx Power     = 0xC8 = 200, 2's compliment is 256-200 = (-56dB)
     *
     * Note: please remember to calibrate your beacons TX Power for more accurate results.
     */
    static const uint8_t uuid[] = {0xE2, 0x0A, 0x39, 0xF4, 0x73, 0xF5, 0x4B, 0xC4,
                                   0xA1, 0x2F, 0x17, 0xD1, 0xAD, 0x07, 0xA9, 0x61};
    uint16_t majorNumber = 1122;
    uint16_t minorNumber = 3344;
    uint16_t txPower     = 0xC8;
    ibeaconPtr = new iBeacon(ble, uuid, majorNumber, minorNumber, txPower);

    ble.gap().setAdvertisingInterval(1000); /* 1000ms. */
    ble.gap().startAdvertising();
}

void scheduleBleEventsProcessing(BLE::OnEventsToProcessCallbackContext* context) {
    BLE &ble = BLE::Instance();
    eventQueue.call(Callback(&ble, &BLE::processEvents));
}

int main()
{
    BLE &ble = BLE::Instance();
    ble.onEventsToProcess(scheduleBleEventsProcessing);
    ble.init(bleInitComplete);

    eventQueue.dispatch_forever();

    return 0;
}

示例:BLE 心率监测器

这是一个示例,演示如何构建可由 BLE 客户端(如手机)连接和监控的心率传感器。

main.cpp                                                                                                                                                   导入到 Mbed IDE

/* mbed Microcontroller Library
 * Copyright (c) 2006-2015 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 
#include 
#include "ble/BLE.h"
#include "ble/Gap.h"
#include "ble/services/HeartRateService.h"

DigitalOut led1(LED1, 1);

const static char     DEVICE_NAME[] = "HRM";
static const uint16_t uuid16_list[] = {GattService::UUID_HEART_RATE_SERVICE};

static uint8_t hrmCounter = 100; // init HRM to 100bps
static HeartRateService *hrServicePtr;

static EventQueue eventQueue(/* event count */ 16 * EVENTS_EVENT_SIZE);

void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *params)
{
    BLE::Instance().gap().startAdvertising(); // restart advertising
}

void updateSensorValue() {
    // Do blocking calls or whatever is necessary for sensor polling.
    // In our case, we simply update the HRM measurement.
    hrmCounter++;

    //  100 <= HRM bps <=175
    if (hrmCounter == 175) {
        hrmCounter = 100;
    }

    hrServicePtr->updateHeartRate(hrmCounter);
}

void periodicCallback(void)
{
    led1 = !led1; /* Do blinky on LED1 while we're waiting for BLE events */

    if (BLE::Instance().getGapState().connected) {
        eventQueue.call(updateSensorValue);
    }
}

void onBleInitError(BLE &ble, ble_error_t error)
{
    (void)ble;
    (void)error;
   /* Initialization error handling should go here */
}

void bleInitComplete(BLE::InitializationCompleteCallbackContext *params)
{
    BLE&        ble   = params->ble;
    ble_error_t error = params->error;

    if (error != BLE_ERROR_NONE) {
        onBleInitError(ble, error);
        return;
    }

    if (ble.getInstanceID() != BLE::DEFAULT_INSTANCE) {
        return;
    }

    ble.gap().onDisconnection(disconnectionCallback);

    /* Setup primary service. */
    hrServicePtr = new HeartRateService(ble, hrmCounter, HeartRateService::LOCATION_FINGER);

    /* Setup advertising. */
    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED | GapAdvertisingData::LE_GENERAL_DISCOVERABLE);
    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LIST_16BIT_SERVICE_IDS, (uint8_t *)uuid16_list, sizeof(uuid16_list));
    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::GENERIC_HEART_RATE_SENSOR);
    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LOCAL_NAME, (uint8_t *)DEVICE_NAME, sizeof(DEVICE_NAME));
    ble.gap().setAdvertisingType(GapAdvertisingParams::ADV_CONNECTABLE_UNDIRECTED);
    ble.gap().setAdvertisingInterval(1000); /* 1000ms */
    ble.gap().startAdvertising();
}

void scheduleBleEventsProcessing(BLE::OnEventsToProcessCallbackContext* context) {
    BLE &ble = BLE::Instance();
    eventQueue.call(Callback(&ble, &BLE::processEvents));
}

int main()
{
    eventQueue.call_every(500, periodicCallback);

    BLE &ble = BLE::Instance();
    ble.onEventsToProcess(scheduleBleEventsProcessing);
    ble.init(bleInitComplete);

    eventQueue.dispatch_forever();

    return 0;
}

  • Mbed 启用支持 BLE 的目标和组件目标和组件。

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