<divclass="textblock"><p>This guide describes the required changes to existing projects migrating from the original bluedroid API to NimBLE.</p>
<p><b>The changes listed here are only the required changes that must be made</b>, and a short overview of options for migrating existing applications.</p>
<p>For more information on the improvements and additions please refer to the <ahref="https://h2zero.github.io/NimBLE-Arduino/annotated.html">class documentation</a> and <aclass="el"href="md__improvements_and_updates.html">Improvements and updates</a></p>
<p>All classes are accessible by including <code><aclass="el"href="_nim_b_l_e_device_8h_source.html">NimBLEDevice.h</a></code> in your application, no further headers need to be included.</p>
<p>(Mainly for Arduino) You may choose to include <code><aclass="el"href="_nim_b_l_e_log_8h_source.html">NimBLELog.h</a></code> in your application if you want to use the <code>NIMBLE_LOGx</code> macros for debugging. These macros are used the same way as the <code>ESP_LOGx</code> macros. <br/>
<p>Class names remain the same as the original with the addition of a "Nim" prefix. For example <code>BLEDevice</code> is now <code><aclass="el"href="class_nim_b_l_e_device.html"title="A model of a BLE Device from which all the BLE roles are created.">NimBLEDevice</a></code> and <code>BLEServer</code> is now <code><aclass="el"href="class_nim_b_l_e_server.html"title="The model of a BLE server.">NimBLEServer</a></code> etc.</p>
<p>For convenience definitions have been added to allow applications to use either name for all classes this means <b>no class names need to be changed in existing code</b> and makes migrating easier. <br/>
<p><code>BLEAddress</code> (<code><aclass="el"href="class_nim_b_l_e_address.html"title="A BLE device address.">NimBLEAddress</a></code>) When constructing an address the constructor now takes an *(optional)* <code>uint8_t type</code> parameter to specify the address type. Default is (0) Public static address.</p>
<p>For example <code>BLEAddress addr(11:22:33:44:55:66, 1)</code> will create the address object with an address type of: 1 (Random).</p>
<p>As this parameter is optional no changes to existing code are needed, it is mentioned here for information.</p>
<p><code>BLEAddress::getNative</code> (<code><aclass="el"href="class_nim_b_l_e_address.html#adef69a03a08303957d7e40eef07b4d80"title="Get the native representation of the address.">NimBLEAddress::getNative</a></code>) returns a uint8_t pointer to the native address byte array. In this library the address bytes are stored in reverse order from the original library. This is due to the way the NimBLE stack expects addresses to be presented to it. All other functions such as <code>toString</code> are not affected as the endian change is made within them. <br/>
<p>Creating a <code>BLEServer</code> instance is the same as original, no changes required. For example <code>BLEDevice::createServer()</code> will work just as it did before.</p>
<p><code>BLEServerCallbacks</code> (<code><aclass="el"href="class_nim_b_l_e_server_callbacks.html"title="Callbacks associated with the operation of a BLE server.">NimBLEServerCallbacks</a></code>) has new methods for handling security operations. <b>Note:</b> All callback methods have default implementations which allows the application to implement only the methods applicable. <br/>
<p>Creating a <code>BLEService</code> (<code><aclass="el"href="class_nim_b_l_e_service.html"title="The model of a BLE service.">NimBLEService</a></code>) instance is the same as original, no changes required. For example <code>BLEServer::createService(SERVICE_UUID)</code> will work just as it did before.</p>
<p><code>BLEService::createCharacteristic</code> (<code><aclass="el"href="class_nim_b_l_e_service.html#a415e1b836946831c6f9edd74adba8763"title="Create a new BLE Characteristic associated with this service.">NimBLEService::createCharacteristic</a></code>) is used the same way as originally except the properties parameter has changed.</p>
<p>When creating a characteristic the properties are now set with <code>NIMBLE_PROPERTY::XXXX</code> instead of <code>BLECharacteristic::XXXX</code>.</p>
</div><!-- fragment --><p> Needs to be changed to: </p><divclass="fragment"><divclass="line">BLECharacteristic *pCharacteristic = pService->createCharacteristic(</div>
<p><code>BLECharacteristicCallbacks</code> (<code><aclass="el"href="class_nim_b_l_e_characteristic_callbacks.html"title="Callbacks that can be associated with a BLE characteristic to inform of events.">NimBLECharacteristicCallbacks</a></code>) has a new method <code><aclass="el"href="class_nim_b_l_e_characteristic_callbacks.html#a3c0c0f524bc0d00d24a7c5ea92c5cb7e"title="Callback function called when a client changes subscription status.">NimBLECharacteristicCallbacks::onSubscribe</a></code> which is called when a client subscribes to notifications/indications.</p>
<p><b>Has been removed from the API.</b> Originally this returned a <code>uint8_t*</code> to the internal data, which is volatile. To prevent possibly throwing exceptions this has been removed and <code><aclass="el"href="class_nim_b_l_e_characteristic.html#a78484a01350300176033a09180f7207f"title="Retrieve the current value of the characteristic.">NimBLECharacteristic::getValue</a></code> should be used to get a copy of the data first which can then safely be accessed via pointer.</p>
</div><!-- fragment --><p> Alternatively use the <code>getValue</code> template: </p><divclass="fragment"><divclass="line">my_struct_t myStruct = pChr->getValue<my_struct_t>();</div>
<p>Descriptors are now created using the <code><aclass="el"href="class_nim_b_l_e_characteristic.html#a1fc55adb9d62d8b5fe1be2b172686353"title="Create a new BLE Descriptor associated with this characteristic.">NimBLECharacteristic::createDescriptor</a></code> method.</p>
<p>BLE2902 or NimBLE2902 class has been removed. NimBLE automatically creates the 0x2902 descriptor if a characteristic has a notification or indication property assigned to it.</p>
<p>It was no longer useful to have a class for the 0x2902 descriptor as a new callback <code><aclass="el"href="class_nim_b_l_e_characteristic_callbacks.html#a3c0c0f524bc0d00d24a7c5ea92c5cb7e"title="Callback function called when a client changes subscription status.">NimBLECharacteristicCallbacks::onSubscribe</a></code> was added to handle callback functionality and the client subscription status is handled internally.</p>
<p><b>Note:</b> Attempting to create a 0x2902 descriptor will trigger an assert to notify the error, allowing the creation of it would cause a fault in the NimBLE stack.</p>
<p>All other descriptors are now created just as characteristics are by using the <code><aclass="el"href="class_nim_b_l_e_characteristic.html#a1fc55adb9d62d8b5fe1be2b172686353"title="Create a new BLE Descriptor associated with this characteristic.">NimBLECharacteristic::createDescriptor</a></code> method (except 0x2904, see below). Which are defined as: </p><divclass="fragment"><divclass="line">NimBLEDescriptor* createDescriptor(const char* uuid,</div>
</div><!-- fragment --><p> Would create a descriptor with the UUID 0xABCD, publicly readable but only writable if paired/bonded (encrypted) and has a max value length of 25 bytes. <br/>
</p>
<p>For the 0x2904, there is a special class that is created when you call `createDescriptor("2904").</p>
<p>The pointer returned is of the base class <code><aclass="el"href="class_nim_b_l_e_descriptor.html"title="A model of a BLE descriptor.">NimBLEDescriptor</a></code> but the call will create the derived class of <code><aclass="el"href="class_nim_b_l_e2904.html"title="Descriptor for Characteristic Presentation Format.">NimBLE2904</a></code> so you must cast the returned pointer to <code><aclass="el"href="class_nim_b_l_e2904.html"title="Descriptor for Characteristic Presentation Format.">NimBLE2904</a></code> to access the specific class methods.</p>
<p>When a peer wants to read or write a characteristic or descriptor with any of these properties applied it will trigger the pairing process. By default the "just-works" pairing will be performed automatically.</p>
<p>This can be changed to use passkey authentication or numeric comparison. See <ahref="#security-api">Security API</a> for details. <br/>
<p>Advertising works the same as the original API except:</p>
<p>Calling <code><aclass="el"href="class_nim_b_l_e_advertising.html#af7083f58717b7e76d90d367f00a0ef08"title="Set the advertisement data that is to be published in a regular advertisement.">NimBLEAdvertising::setAdvertisementData</a></code> will entirely replace any data set with <code><aclass="el"href="class_nim_b_l_e_advertising.html#a4f334752ea04223185292fe9ab524b69"title="Add a service uuid to exposed list of services.">NimBLEAdvertising::addServiceUUID</a></code>, or <code><aclass="el"href="class_nim_b_l_e_advertising.html#aa0d30dfb57670cc8180e17dffddad416"title="Set the device appearance in the advertising data. The codes for distinct appearances can be found he...">NimBLEAdvertising::setAppearance</a></code> or similar methods. You should set all the data you wish to advertise within the <code><aclass="el"href="class_nim_b_l_e_advertisement_data.html"title="Advertisement data set by the programmer to be published by the BLE server.">NimBLEAdvertisementData</a></code> instead. <br/>
<p>Now takes 2 optional parameters, the first is the duration to advertise for (in seconds), the second is a callback that is invoked when advertising ends and takes a pointer to a <code><aclass="el"href="class_nim_b_l_e_advertising.html"title="Perform and manage BLE advertising.">NimBLEAdvertising</a></code> object (similar to the <code><aclass="el"href="class_nim_b_l_e_scan.html#a21b1e27816717b77533755f31dfaa820"title="Start scanning.">NimBLEScan::start</a></code> API). This provides an opportunity to update the advertisement data if desired. <br/>
<p>Client instances are created just as before with <code>BLEDevice::createClient</code> (<code><aclass="el"href="class_nim_b_l_e_device.html#af8142995252f486916dbb9de2a5b0c9e"title="Creates a new client object and maintains a list of all client objects each client can connect to 1 p...">NimBLEDevice::createClient</a></code>).</p>
<p>Multiple client instances can be created, up to the maximum number of connections set in the config file (default: 3). To delete a client instance you must use <code><aclass="el"href="class_nim_b_l_e_device.html#a83aa0a3d9d57358d35082a442edf8549"title="Delete the client object and remove it from the list. Checks if it is connected or trying to connect ...">NimBLEDevice::deleteClient</a></code>.</p>
<p><code>BLEClient::connect</code>(<code><aclass="el"href="class_nim_b_l_e_client.html#ae9b3e8a9b47c7eaad040b485bda958a1"title="Connect to an advertising device.">NimBLEClient::connect</a></code>) Has had it's parameters altered. Defined as: </p><blockquoteclass="doxtable">
<p><aclass="el"href="class_nim_b_l_e_client.html#ae9b3e8a9b47c7eaad040b485bda958a1"title="Connect to an advertising device.">NimBLEClient::connect</a>(bool deleteServices = true); <aclass="el"href="class_nim_b_l_e_client.html#ae9b3e8a9b47c7eaad040b485bda958a1"title="Connect to an advertising device.">NimBLEClient::connect</a>(NimBLEAdvertisedDevice* device, bool deleteServices = true); <aclass="el"href="class_nim_b_l_e_client.html#ae9b3e8a9b47c7eaad040b485bda958a1"title="Connect to an advertising device.">NimBLEClient::connect</a>(<aclass="el"href="class_nim_b_l_e_address.html"title="A BLE device address.">NimBLEAddress</a> address, bool deleteServices = true); </p>
<p>The type parameter has been removed and a new bool parameter has been added to indicate if the client should delete the attribute database previously retrieved (if applicable) for the peripheral, default value is true.</p>
<p>If set to false the client will use the attribute database it retrieved from the peripheral when previously connected.</p>
<p>This allows for faster connections and power saving if the devices dropped connection and are reconnecting. <br/>
<p><code>BLEClient::getServices</code> (<code><aclass="el"href="class_nim_b_l_e_client.html#acb9007569b3bb13b3b49f3c4cb47b21a"title="Get a pointer to the vector of found services.">NimBLEClient::getServices</a></code>) </p>
<p>This method now takes an optional (bool) parameter to indicate if the services should be retrieved from the server (true) or the currently known database returned (false : default). Also now returns a pointer to <code>std::vector</code> instead of <code>std::map</code>. <br/>
<p><b>Removed:</b> the automatic discovery of all peripheral attributes as they consumed time and resources for data the user may not be interested in.</p>
<p><b>Added:</b><code><aclass="el"href="class_nim_b_l_e_client.html#a1019178a12799ca2c3a84f523b3a7db9"title="Retrieves the full database of attributes that the peripheral has available.">NimBLEClient::discoverAttributes</a></code> for the user to discover all the peripheral attributes to replace the the removed automatic functionality. <br/>
<p><code>BLERemoteService</code> (<code><aclass="el"href="class_nim_b_l_e_remote_service.html"title="A model of a remote BLE service.">NimBLERemoteService</a></code>) Methods remain mostly unchanged with the exceptions of:</p>
<p><code>BLERemoteService::getCharacteristics</code> (<code><aclass="el"href="class_nim_b_l_e_remote_service.html#a2c9e91c842598a6a9576c7b87af0863a"title="Get a pointer to the vector of found characteristics.">NimBLERemoteService::getCharacteristics</a></code>) </p>
<p>This method now takes an optional (bool) parameter to indicate if the characteristics should be retrieved from the server (true) or the currently known database returned (false : default). Also now returns a pointer to <code>std::vector</code> instead of <code>std::map</code>. <br/>
<p><code>BLERemoteCharacteristic</code> (<code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html"title="A model of a remote BLE characteristic.">NimBLERemoteCharacteristic</a></code>) There have been a few changes to the methods in this class:</p>
<p><code>BLERemoteCharacteristic::writeValue</code> (<code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#a3c8d1fd77dd074df866c091c614eafb3"title="Write a new value to the remote characteristic from a data buffer.">NimBLERemoteCharacteristic::writeValue</a></code>) <code>BLERemoteCharacteristic::registerForNotify</code> (<code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#ab4f54eabe90a416546b7b3fc3477f49c"title="backward-compatibility method for subscribe/unsubscribe notifications/indications">NimBLERemoteCharacteristic::registerForNotify</a></code>) </p>
<p>Is now <b>deprecated</b>. </p><blockquoteclass="doxtable">
<p><code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#ad2691a8ea85488c8270f78701352fbb2"title="Subscribe for notifications or indications.">NimBLERemoteCharacteristic::subscribe</a></code><code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#ae2791429ba4a8c310ffc24139a985da6"title="Unsubscribe for notifications or indications.">NimBLERemoteCharacteristic::unsubscribe</a></code></p>
<p><code>BLERemoteCharacteristic::readUInt8</code> (<code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#ade5c6ae280c3cf36c9905be23df8f080"title="Read a byte value.">NimBLERemoteCharacteristic::readUInt8</a></code>) <code>BLERemoteCharacteristic::readUInt16</code> (<code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#a181c54862bc422d8ad0b326af675922d"title="Read an unsigned 16 bit value.">NimBLERemoteCharacteristic::readUInt16</a></code>) <code>BLERemoteCharacteristic::readUInt32</code> (<code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#a71793454ffab034f87af3a5e9677a63d"title="Read an unsigned 32 bit value.">NimBLERemoteCharacteristic::readUInt32</a></code>) <code>BLERemoteCharacteristic::readFloat</code> (<code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#a81f39759d48a8fb792c94e4b3b455eef"title="Read a float value.">NimBLERemoteCharacteristic::readFloat</a></code>) </p>
<p>Are <b>deprecated</b> a template: <code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#a417bb44d000758535253488f4d77774a"title="Read the value of the remote characteristic.">NimBLERemoteCharacteristic::readValue</a><type\>(time_t\*, bool)</code> has been added to replace them. <br/>
<p><b>Has been removed from the API</b> Originally it stored an unnecessary copy of the data and was returning a <code>uint8_t</code> pointer to volatile internal data. The user application should use <code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#a417bb44d000758535253488f4d77774a"title="Read the value of the remote characteristic.">NimBLERemoteCharacteristic::readValue</a></code> or <code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#a6d0779ffe7e89449121428e7fd6083d8"title="Get the value of the remote characteristic.">NimBLERemoteCharacteristic::getValue</a></code>. To obtain a copy of the data, then cast the returned std::string to the type required such as: </p><divclass="fragment"><divclass="line">std::string value = pChr->readValue();</div>
</div><!-- fragment --><p> Alternatively use the <code>readValue</code> template: </p><divclass="fragment"><divclass="line">my_struct_t myStruct = pChr->readValue<my_struct_t>();</div>
<p><code>BLERemoteCharacteristic::getDescriptors</code> (<code><aclass="el"href="class_nim_b_l_e_remote_characteristic.html#acf11d225fe5a25327742349e9d6061f9"title="Get a pointer to the vector of found descriptors.">NimBLERemoteCharacteristic::getDescriptors</a></code>) </p>
<p>This method now takes an optional (bool) parameter to indicate if the descriptors should be retrieved from the server (true) or the currently known database returned (false : default). Also now returns a pointer to <code>std::vector</code> instead of <code>std::map</code>. <br/>
<p>The client will automatically initiate security when the peripheral responds that it's required. The default configuration will use "just-works" pairing with no bonding, if you wish to enable bonding see below. <br/>
<p>Security operations have been moved to <code>BLEDevice</code> (<code><aclass="el"href="class_nim_b_l_e_device.html"title="A model of a BLE Device from which all the BLE roles are created.">NimBLEDevice</a></code>).</p>
<p>Also security callback methods are now incorporated in the <code><aclass="el"href="class_nim_b_l_e_server_callbacks.html"title="Callbacks associated with the operation of a BLE server.">NimBLEServerCallbacks</a></code> / <code><aclass="el"href="class_nim_b_l_e_client_callbacks.html"title="Callbacks associated with a BLE client.">NimBLEClientCallbacks</a></code> classes. However backward compatibility with the original <code>BLESecurity</code> (<code><aclass="el"href="class_nim_b_l_e_security.html"title="A class to handle BLE security operations. Deprecated - provided for backward compatibility only.">NimBLESecurity</a></code>) class is retained to minimize application code changes.</p>
<p>Authentication complete, success or failed information is in <code>desc</code>. <br/>
</p>
<p>Security settings and IO capabilities are now set by the following methods of <aclass="el"href="class_nim_b_l_e_device.html"title="A model of a BLE Device from which all the BLE roles are created.">NimBLEDevice</a>. </p><blockquoteclass="doxtable">
<p><code><aclass="el"href="class_nim_b_l_e_device.html#aa8e340c02418771ce72dec758d560938"title="Set the authorization mode for this device.">NimBLEDevice::setSecurityAuth(bool bonding, bool mitm, bool sc)</a></code><code><aclass="el"href="class_nim_b_l_e_device.html#a2f10da171794581870d678fc947a5d1f"title="Set the authorization mode for this device.">NimBLEDevice::setSecurityAuth(uint8_t auth_req)</a></code></p>
<p><code><aclass="el"href="class_nim_b_l_e_device.html#ab9fee9e810d5fa18bc8a37053eb9b5d0"title="Set the Input/Output capabilities of this device.">NimBLEDevice::setSecurityIOCap(uint8_t iocap)</a></code></p>
<p><code><aclass="el"href="class_nim_b_l_e_device.html#a92d36c3a34d9474fa1d7f66c0e477d1e"title="If we are the initiator of the security procedure this sets the keys we will distribute.">NimBLEDevice::setSecurityInitKey(uint8_t init_key)</a></code></p>
<p><code><aclass="el"href="class_nim_b_l_e_device.html#a57f0d4db1cc564176b23e860fce13f6a"title="Set the keys we are willing to accept during pairing.">NimBLEDevice::setSecurityRespKey(uint8_t resp_key)</a></code></p>
<p>Unlike the original library pre-packaged in the esp32-arduino, this library has all the configuration options that are normally set in menuconfig available in the <em><aclass="el"href="nimconfig_8h.html">src/nimconfig.h</a></em> file.</p>
<p>This allows Arduino users to fully customize the build, such as increasing max connections or loading the BLE stack into external PSRAM.</p>
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