This is an example of BLE GATT Client, which receives broadcast data from BLE_Server_BME280 ( a GATT server) , then transfers values up to mbed Device Connector (cloud).

Please refer details about BLEClient_mbedDevConn below. https://github.com/soramame21/BLEClient_mbedDevConn

The location of required BLE GATT server, BLE_Server_BME280, is at here. https://developer.mbed.org/users/edamame22/code/BLE_Server_BME280/

Revision:
0:29983394c6b6
diff -r 000000000000 -r 29983394c6b6 mbed-client/mbed-client-mbed-tls/mbed-client-mbedtls/m2mconnectionsecuritypimpl.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-client/mbed-client-mbed-tls/mbed-client-mbedtls/m2mconnectionsecuritypimpl.h	Thu Apr 13 04:48:11 2017 +0000
@@ -0,0 +1,161 @@
+/*
+ * Copyright (c) 2015 ARM Limited. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ * 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.
+ */
+
+#ifndef __M2M_CONNECTION_SECURITY_PIMPL_H__
+#define __M2M_CONNECTION_SECURITY_PIMPL_H__
+
+#include "mbed-client/m2mconnectionsecurity.h"
+#include "mbed-client/m2mtimerobserver.h"
+#include "mbed-client/m2mconstants.h"
+#include "mbed-client/m2msecurity.h"
+
+#include "mbedtls/config.h"
+#include "mbedtls/platform.h"
+#include "mbedtls/debug.h"
+#include "mbedtls/ssl.h"
+#include "mbedtls/entropy.h"
+#include "mbedtls/ctr_drbg.h"
+#include "mbedtls/error.h"
+#include "mbedtls/certs.h"
+#include "mbedtls/entropy_poll.h"
+
+class M2MTimer;
+
+//TODO: Should we let application to select these or not??
+const static int PSK_SUITES[] = {
+    MBEDTLS_TLS_PSK_WITH_AES_128_CBC_SHA256,
+    MBEDTLS_TLS_PSK_WITH_AES_256_CCM_8,
+    MBEDTLS_TLS_PSK_WITH_AES_128_CCM_8,
+    0
+};
+
+
+/**
+ * @brief The M2MConnectionSecurityPimpl class
+ */
+class M2MConnectionSecurityPimpl : public M2MTimerObserver {
+
+private:
+
+    // Prevents the use of assignment operator by accident.
+    M2MConnectionSecurityPimpl& operator=( const M2MConnectionSecurityPimpl& /*other*/ );
+    // Prevents the use of copy constructor by accident
+    M2MConnectionSecurityPimpl( const M2MConnectionSecurityPimpl& /*other*/ );
+
+public:
+
+    /**
+     * @brief Constructor
+     */
+    M2MConnectionSecurityPimpl(M2MConnectionSecurity::SecurityMode mode);
+
+    /**
+    * @brief Destructor
+    */
+    virtual ~M2MConnectionSecurityPimpl();
+
+    /**
+     * \brief Resets the socket connection states.
+     */
+    void reset();
+
+    /**
+     * \brief Initiatlizes the socket connection states.
+     */
+    int init(const M2MSecurity *security);
+
+    /**
+     * \brief Starts the connection in non-blocking mode.
+     * \param connHandler The ConnectionHandler object that maintains the socket.
+     * \return Returns the state of the connection. Successful or not.
+     */
+    int start_connecting_non_blocking(M2MConnectionHandler* connHandler);
+
+    /**
+     * \brief Continues connectivity logic for secure connection.
+     * \return Returns an error code if any while continuing the connection sequence.
+     */
+    int continue_connecting();
+
+    /**
+     * \brief Connects the client to the server.
+     * \param connHandler The ConnectionHandler object that maintains the socket.
+     * \return Returns the state of the connection. Successful or not.
+     */
+    int connect(M2MConnectionHandler* connHandler);
+
+    /**
+     * \brief Sends data to the server.
+     * \param message The data to be sent.
+     * \param len The length of the data.
+     * @return Indicates whether the data is sent successfully or not.
+     */
+    int send_message(unsigned char *message, int len);
+
+    /**
+     * \brief Reads the data received from the server.
+     * \param message The data to be read.
+     * \param len The length of the data.
+     * \return Indicates whether the data is read successfully or not.
+     */
+    int read(unsigned char* buffer, uint16_t len);
+
+    /**
+     * \brief Sets the function callback that will be called by mbed-client for
+     * fetching random number from application for ensuring strong entropy.
+     * \param random_callback A function pointer that will be called by mbed-client
+     * while performing secure handshake.
+     * Function signature should be uint32_t (*random_number_callback)(void);
+     */
+    void set_random_number_callback(random_number_cb callback);
+
+    /**
+     * \brief Sets the function callback that will be called by mbed-client for
+     * providing entropy source from application for ensuring strong entropy.
+     * \param entropy_callback A function pointer that will be called by mbed-client
+     * while performing secure handshake.
+     * Function signature , if using mbed-client-mbedtls should be
+     * int (*mbedtls_entropy_f_source_ptr)(void *data, unsigned char *output,
+     *                                     size_t len, size_t *olen);
+     */
+    void set_entropy_callback(entropy_cb callback);
+
+protected: //From M2MTimerObserver
+
+    virtual void timer_expired(M2MTimerObserver::Type type);
+
+private:
+
+    int start_handshake();
+
+private:
+
+    bool                        _init_done;
+    mbedtls_ssl_config          _conf;
+    mbedtls_ssl_context         _ssl;
+    mbedtls_x509_crt            _cacert;
+    mbedtls_x509_crt            _owncert;
+    mbedtls_pk_context          _pkey;
+    mbedtls_ctr_drbg_context    _ctr_drbg;
+    mbedtls_entropy_context     _entropy;
+    uint32_t                    _flags;
+    M2MTimer                    *_timer;
+    M2MConnectionSecurity::SecurityMode _sec_mode;
+
+    friend class Test_M2MConnectionSecurityPimpl;
+};
+
+#endif //__M2M_CONNECTION_SECURITY_PIMPL_H__