How to update advertised TX power?

Question

Using the 15.3 SDK and the 6.1 software device I am successfully changing the transmit power as needed. When not connected and advertising I would like to update the advertised TX power initialized with: 
 init.srdata.p_tx_power_level 
 I have read multiple, multiple posts to DevZone regarding updating the advertising information but so many are out of date or links are broken. Given advertising the transmit power must be a rather routine situation I'm assuming there is some simple way to do the update. If there is not a simple way could you provide a complete SDK 15.3, SD 6.1 compatible method example please? I'm sure others would appreciate a recent example. 
 Any help would be appreciated as we are doing a pre-production run in China in about two weeks and I would like to have this addressed. I'm not willing to update to SDK 16.0 because of how close to pre-production date. 
 
 Sincerely, 
 Michael M.

Einar Thorsrud · Accepted Answer

Hi Michael, As Susheel wrote, the only thing you need to do to update the advertising data in the scan response or advertising packet is to call sd_ble_gap_adv_set_configure() with the new advertising buffer. So essentially you just build it like before, changing the tx_power field. Since you are just updating the advertising data, the third/last parameter should be NULL, to keep the old configuration. If you are currently advertising, you need to use a different memory buffer for the advertising set, since the SoftDevice does not allow updating an advertising buffer that is currently in use. You can refer to the attached file, which is the BLE blinky application for SDK 15.3, modified so that you can pus button 2 to change the Tx power and the Tx power that is advertised. This drops right into the BLE Blinky example application project if you want to test it. Fullscreen main.c Download /** * Copyright (c) 2015 - 2019, Nordic Semiconductor ASA * * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * 2. Redistributions in binary form, except as embedded into a Nordic * Semiconductor ASA integrated circuit in a product or a software update for * such product, must reproduce the above copyright notice, this list of * conditions and the following disclaimer in the documentation and/or other * materials provided with the distribution. * * 3. Neither the name of Nordic Semiconductor ASA nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * 4. This software, with or without modification, must only be used with a * Nordic Semiconductor ASA integrated circuit. * * 5. Any software provided in binary form under this license must not be reverse * engineered, decompiled, modified and/or disassembled. * * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ /** * @brief Blinky Sample Application main file. * * This file contains the source code for a sample server application using the LED Button service. */ #include #include #include "nordic_common.h" #include "nrf.h" #include "app_error.h" #include "ble.h" #include "ble_err.h" #include "ble_hci.h" #include "ble_srv_common.h" #include "ble_advdata.h" #include "ble_conn_params.h" #include "nrf_sdh.h" #include "nrf_sdh_ble.h" #include "boards.h" #include "app_timer.h" #include "app_button.h" #include "ble_lbs.h" #include "nrf_ble_gatt.h" #include "nrf_ble_qwr.h" #include "nrf_pwr_mgmt.h" #include "nrf_log.h" #include "nrf_log_ctrl.h" #include "nrf_log_default_backends.h" #define ADVERTISING_LED BSP_BOARD_LED_0 /**< Is on when device is advertising. */ #define CONNECTED_LED BSP_BOARD_LED_1 /**< Is on when device has connected. */ #define LEDBUTTON_LED BSP_BOARD_LED_2 /**< LED to be toggled with the help of the LED Button Service. */ #define LEDBUTTON_BUTTON BSP_BUTTON_0 /**< Button that will trigger the notification event with the LED Button Service */ #define DEVICE_NAME "Nordic_Blinky" /**< Name of device. Will be included in the advertising data. */ #define APP_BLE_OBSERVER_PRIO 3 /**< Application's BLE observer priority. You shouldn't need to modify this value. */ #define APP_BLE_CONN_CFG_TAG 1 /**< A tag identifying the SoftDevice BLE configuration. */ #define APP_ADV_INTERVAL 64 /**< The advertising interval (in units of 0.625 ms; this value corresponds to 40 ms). */ #define APP_ADV_DURATION BLE_GAP_ADV_TIMEOUT_GENERAL_UNLIMITED /**< The advertising time-out (in units of seconds). When set to 0, we will never time out. */ #define MIN_CONN_INTERVAL MSEC_TO_UNITS(100, UNIT_1_25_MS) /**< Minimum acceptable connection interval (0.5 seconds). */ #define MAX_CONN_INTERVAL MSEC_TO_UNITS(200, UNIT_1_25_MS) /**< Maximum acceptable connection interval (1 second). */ #define SLAVE_LATENCY 0 /**< Slave latency. */ #define CONN_SUP_TIMEOUT MSEC_TO_UNITS(4000, UNIT_10_MS) /**< Connection supervisory time-out (4 seconds). */ #define FIRST_CONN_PARAMS_UPDATE_DELAY APP_TIMER_TICKS(20000) /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (15 seconds). */ #define NEXT_CONN_PARAMS_UPDATE_DELAY APP_TIMER_TICKS(5000) /**< Time between each call to sd_ble_gap_conn_param_update after the first call (5 seconds). */ #define MAX_CONN_PARAMS_UPDATE_COUNT 3 /**< Number of attempts before giving up the connection parameter negotiation. */ #define BUTTON_DETECTION_DELAY APP_TIMER_TICKS(50) /**< Delay from a GPIOTE event until a button is reported as pushed (in number of timer ticks). */ #define DEAD_BEEF 0xDEADBEEF /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */ #define INITIAL_ADV_BUF_OFFSET 0 BLE_LBS_DEF(m_lbs); /**< LED Button Service instance. */ NRF_BLE_GATT_DEF(m_gatt); /**< GATT module instance. */ NRF_BLE_QWR_DEF(m_qwr); /**< Context for the Queued Write module.*/ static uint16_t m_conn_handle = BLE_CONN_HANDLE_INVALID; /**< Handle of the current connection. */ static uint8_t m_adv_handle = BLE_GAP_ADV_SET_HANDLE_NOT_SET; /**< Advertising handle used to identify an advertising set. */ static uint8_t m_enc_advdata[2][BLE_GAP_ADV_SET_DATA_SIZE_MAX]; /**< Buffers for storing an encoded advertising set. */ static uint8_t m_enc_scan_response_data[2][BLE_GAP_ADV_SET_DATA_SIZE_MAX]; /**< Buffers for storing an encoded scan data. */ static int8_t m_tx_power = 0; static const int8_t m_tx_power_list[] = {0, -8, -20}; static uint32_t m_tx_power_index = 0; static uint8_t m_adv_buff_offset = INITIAL_ADV_BUF_OFFSET; /**@brief Struct that contains pointers to the encoded advertising data. */ static ble_gap_adv_data_t m_adv_data = { .adv_data = { .p_data = m_enc_advdata[INITIAL_ADV_BUF_OFFSET], .len = BLE_GAP_ADV_SET_DATA_SIZE_MAX }, .scan_rsp_data = { .p_data = m_enc_scan_response_data[INITIAL_ADV_BUF_OFFSET], .len = BLE_GAP_ADV_SET_DATA_SIZE_MAX } }; static void adv_data_buf_swap(void) { m_adv_buff_offset = (m_adv_buff_offset + 1) % 2; m_adv_data.adv_data.p_data = m_enc_advdata[m_adv_buff_offset]; m_adv_data.scan_rsp_data.p_data = m_enc_scan_response_data[m_adv_buff_offset]; } /**@brief Function for assert macro callback. * * @details This function will be called in case of an assert in the SoftDevice. * * @warning This handler is an example only and does not fit a final product. You need to analyze * how your product is supposed to react in case of Assert. * @warning On assert from the SoftDevice, the system can only recover on reset. * * @param[in] line_num Line number of the failing ASSERT call. * @param[in] p_file_name File name of the failing ASSERT call. */ void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name) { app_error_handler(DEAD_BEEF, line_num, p_file_name); } /**@brief Function for the LEDs initialization. * * @details Initializes all LEDs used by the application. */ static void leds_init(void) { bsp_board_init(BSP_INIT_LEDS); } /**@brief Function for the Timer initialization. * * @details Initializes the timer module. */ static void timers_init(void) { // Initialize timer module, making it use the scheduler ret_code_t err_code = app_timer_init(); APP_ERROR_CHECK(err_code); } /**@brief Function for the GAP initialization. * * @details This function sets up all the necessary GAP (Generic Access Profile) parameters of the * device including the device name, appearance, and the preferred connection parameters. */ static void gap_params_init(void) { ret_code_t err_code; ble_gap_conn_params_t gap_conn_params; ble_gap_conn_sec_mode_t sec_mode; BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode); err_code = sd_ble_gap_device_name_set(&sec_mode, (const uint8_t *)DEVICE_NAME, strlen(DEVICE_NAME)); APP_ERROR_CHECK(err_code); memset(&gap_conn_params, 0, sizeof(gap_conn_params)); gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL; gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL; gap_conn_params.slave_latency = SLAVE_LATENCY; gap_conn_params.conn_sup_timeout = CONN_SUP_TIMEOUT; err_code = sd_ble_gap_ppcp_set(&gap_conn_params); APP_ERROR_CHECK(err_code); } /**@brief Function for initializing the GATT module. */ static void gatt_init(void) { ret_code_t err_code = nrf_ble_gatt_init(&m_gatt, NULL); APP_ERROR_CHECK(err_code); } static void advertising_data_build(void) { ret_code_t err_code; ble_uuid_t adv_uuids[] = {{LBS_UUID_SERVICE, m_lbs.uuid_type}}; ble_advdata_t advdata; ble_advdata_t srdata; memset(&advdata, 0, sizeof(advdata)); advdata.name_type = BLE_ADVDATA_FULL_NAME; advdata.include_appearance = true; advdata.flags = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE; memset(&srdata, 0, sizeof(srdata)); srdata.uuids_complete.uuid_cnt = sizeof(adv_uuids) / sizeof(adv_uuids[0]); srdata.uuids_complete.p_uuids = adv_uuids; srdata.p_tx_power_level = &m_tx_power; err_code = ble_advdata_encode(&advdata, m_adv_data.adv_data.p_data, &m_adv_data.adv_data.len); APP_ERROR_CHECK(err_code); err_code = ble_advdata_encode(&srdata, m_adv_data.scan_rsp_data.p_data, &m_adv_data.scan_rsp_data.len); APP_ERROR_CHECK(err_code); } /**@brief Function for initializing the Advertising functionality. * * @details Encodes the required advertising data and passes it to the stack. * Also builds a structure to be passed to the stack when starting advertising. */ static void advertising_init(void) { ret_code_t err_code; ble_gap_adv_params_t adv_params; // Build and set advertising data. advertising_data_build(); // Set advertising parameters. memset(&adv_params, 0, sizeof(adv_params)); adv_params.primary_phy = BLE_GAP_PHY_1MBPS; adv_params.duration = APP_ADV_DURATION; adv_params.properties.type = BLE_GAP_ADV_TYPE_CONNECTABLE_SCANNABLE_UNDIRECTED; adv_params.p_peer_addr = NULL; adv_params.filter_policy = BLE_GAP_ADV_FP_ANY; adv_params.interval = APP_ADV_INTERVAL; err_code = sd_ble_gap_adv_set_configure(&m_adv_handle, &m_adv_data, &adv_params); APP_ERROR_CHECK(err_code); } static void advertising_update(void) { ret_code_t err_code; // Use other advertising buffers since updating a currently used buffer is not allowed by the SoftDevice adv_data_buf_swap(); // Build and set advertising data. advertising_data_build(); // Configure SoftDevice to use new advertising data without changing other configuration err_code = sd_ble_gap_adv_set_configure(&m_adv_handle, &m_adv_data, NULL); APP_ERROR_CHECK(err_code); } /**@brief Function for handling Queued Write Module errors. * * @details A pointer to this function will be passed to each service which may need to inform the * application about an error. * * @param[in] nrf_error Error code containing information about what went wrong. */ static void nrf_qwr_error_handler(uint32_t nrf_error) { APP_ERROR_HANDLER(nrf_error); } /**@brief Function for handling write events to the LED characteristic. * * @param[in] p_lbs Instance of LED Button Service to which the write applies. * @param[in] led_state Written/desired state of the LED. */ static void led_write_handler(uint16_t conn_handle, ble_lbs_t * p_lbs, uint8_t led_state) { if (led_state) { bsp_board_led_on(LEDBUTTON_LED); NRF_LOG_INFO("Received LED ON!"); } else { bsp_board_led_off(LEDBUTTON_LED); NRF_LOG_INFO("Received LED OFF!"); } } /**@brief Function for initializing services that will be used by the application. */ static void services_init(void) { ret_code_t err_code; ble_lbs_init_t init = {0}; nrf_ble_qwr_init_t qwr_init = {0}; // Initialize Queued Write Module. qwr_init.error_handler = nrf_qwr_error_handler; err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init); APP_ERROR_CHECK(err_code); // Initialize LBS. init.led_write_handler = led_write_handler; err_code = ble_lbs_init(&m_lbs, &init); APP_ERROR_CHECK(err_code); } /**@brief Function for handling the Connection Parameters Module. * * @details This function will be called for all events in the Connection Parameters Module that * are passed to the application. * * @note All this function does is to disconnect. This could have been done by simply * setting the disconnect_on_fail config parameter, but instead we use the event * handler mechanism to demonstrate its use. * * @param[in] p_evt Event received from the Connection Parameters Module. */ static void on_conn_params_evt(ble_conn_params_evt_t * p_evt) { ret_code_t err_code; if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED) { err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE); APP_ERROR_CHECK(err_code); } } /**@brief Function for handling a Connection Parameters error. * * @param[in] nrf_error Error code containing information about what went wrong. */ static void conn_params_error_handler(uint32_t nrf_error) { APP_ERROR_HANDLER(nrf_error); } /**@brief Function for initializing the Connection Parameters module. */ static void conn_params_init(void) { ret_code_t err_code; ble_conn_params_init_t cp_init; memset(&cp_init, 0, sizeof(cp_init)); cp_init.p_conn_params = NULL; cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY; cp_init.next_conn_params_update_delay = NEXT_CONN_PARAMS_UPDATE_DELAY; cp_init.max_conn_params_update_count = MAX_CONN_PARAMS_UPDATE_COUNT; cp_init.start_on_notify_cccd_handle = BLE_GATT_HANDLE_INVALID; cp_init.disconnect_on_fail = false; cp_init.evt_handler = on_conn_params_evt; cp_init.error_handler = conn_params_error_handler; err_code = ble_conn_params_init(&cp_init); APP_ERROR_CHECK(err_code); } /**@brief Function for starting advertising. */ static void advertising_start(void) { ret_code_t err_code; err_code = sd_ble_gap_adv_start(m_adv_handle, APP_BLE_CONN_CFG_TAG); APP_ERROR_CHECK(err_code); bsp_board_led_on(ADVERTISING_LED); } /**@brief Function for handling BLE events. * * @param[in] p_ble_evt Bluetooth stack event. * @param[in] p_context Unused. */ static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context) { ret_code_t err_code; switch (p_ble_evt->header.evt_id) { case BLE_GAP_EVT_CONNECTED: NRF_LOG_INFO("Connected"); bsp_board_led_on(CONNECTED_LED); bsp_board_led_off(ADVERTISING_LED); m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle; err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle); APP_ERROR_CHECK(err_code); //err_code = app_button_enable(); APP_ERROR_CHECK(err_code); break; case BLE_GAP_EVT_DISCONNECTED: NRF_LOG_INFO("Disconnected"); bsp_board_led_off(CONNECTED_LED); m_conn_handle = BLE_CONN_HANDLE_INVALID; //err_code = app_button_disable(); APP_ERROR_CHECK(err_code); advertising_start(); break; case BLE_GAP_EVT_SEC_PARAMS_REQUEST: // Pairing not supported err_code = sd_ble_gap_sec_params_reply(m_conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL); APP_ERROR_CHECK(err_code); break; case BLE_GAP_EVT_PHY_UPDATE_REQUEST: { NRF_LOG_DEBUG("PHY update request."); ble_gap_phys_t const phys = { .rx_phys = BLE_GAP_PHY_AUTO, .tx_phys = BLE_GAP_PHY_AUTO, }; err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys); APP_ERROR_CHECK(err_code); } break; case BLE_GATTS_EVT_SYS_ATTR_MISSING: // No system attributes have been stored. err_code = sd_ble_gatts_sys_attr_set(m_conn_handle, NULL, 0, 0); APP_ERROR_CHECK(err_code); break; case BLE_GATTC_EVT_TIMEOUT: // Disconnect on GATT Client timeout event. NRF_LOG_DEBUG("GATT Client Timeout."); err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION); APP_ERROR_CHECK(err_code); break; case BLE_GATTS_EVT_TIMEOUT: // Disconnect on GATT Server timeout event. NRF_LOG_DEBUG("GATT Server Timeout."); err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION); APP_ERROR_CHECK(err_code); break; default: // No implementation needed. break; } } /**@brief Function for initializing the BLE stack. * * @details Initializes the SoftDevice and the BLE event interrupt. */ static void ble_stack_init(void) { ret_code_t err_code; err_code = nrf_sdh_enable_request(); APP_ERROR_CHECK(err_code); // Configure the BLE stack using the default settings. // Fetch the start address of the application RAM. uint32_t ram_start = 0; err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start); APP_ERROR_CHECK(err_code); // Enable BLE stack. err_code = nrf_sdh_ble_enable(&ram_start); APP_ERROR_CHECK(err_code); // Register a handler for BLE events. NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL); } static void update_tx_power(void) { ret_code_t err_code; m_tx_power = m_tx_power_list[++m_tx_power_index % sizeof(m_tx_power_list)]; NRF_LOG_INFO("Update TX power to %i dBm", m_tx_power); // Set new TX power err_code = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV, m_adv_handle, m_tx_power); APP_ERROR_CHECK(err_code); // Update advertising data to include current Tx power advertising_update(); } /**@brief Function for handling events from the button handler module. * * @param[in] pin_no The pin that the event applies to. * @param[in] button_action The button action (press/release). */ static void button_event_handler(uint8_t pin_no, uint8_t button_action) { ret_code_t err_code; switch (pin_no) { case LEDBUTTON_BUTTON: err_code = ble_lbs_on_button_change(m_conn_handle, &m_lbs, button_action); if (err_code != NRF_SUCCESS && err_code != BLE_ERROR_INVALID_CONN_HANDLE && err_code != NRF_ERROR_INVALID_STATE && err_code != BLE_ERROR_GATTS_SYS_ATTR_MISSING) { APP_ERROR_CHECK(err_code); } break; case BSP_BUTTON_1: if (button_action == APP_BUTTON_PUSH) { NRF_LOG_INFO("Send button state change."); update_tx_power(); } break; default: APP_ERROR_HANDLER(pin_no); break; } } /**@brief Function for initializing the button handler module. */ static void buttons_init(void) { ret_code_t err_code; //The array must be static because a pointer to it will be saved in the button handler module. static app_button_cfg_t buttons[] = { {LEDBUTTON_BUTTON, false, BUTTON_PULL, button_event_handler}, {BSP_BUTTON_1, false, BUTTON_PULL, button_event_handler} }; err_code = app_button_init(buttons, ARRAY_SIZE(buttons), BUTTON_DETECTION_DELAY); APP_ERROR_CHECK(err_code); err_code = app_button_enable(); APP_ERROR_CHECK(err_code); } static void log_init(void) { ret_code_t err_code = NRF_LOG_INIT(NULL); APP_ERROR_CHECK(err_code); NRF_LOG_DEFAULT_BACKENDS_INIT(); } /**@brief Function for initializing power management. */ static void power_management_init(void) { ret_code_t err_code; err_code = nrf_pwr_mgmt_init(); APP_ERROR_CHECK(err_code); } /**@brief Function for handling the idle state (main loop). * * @details If there is no pending log operation, then sleep until next the next event occurs. */ static void idle_state_handle(void) { if (NRF_LOG_PROCESS() == false) { nrf_pwr_mgmt_run(); } } /**@brief Function for application main entry. */ int main(void) { // Initialize. log_init(); leds_init(); timers_init(); buttons_init(); power_management_init(); ble_stack_init(); gap_params_init(); gatt_init(); services_init(); advertising_init(); conn_params_init(); // Start execution. NRF_LOG_INFO("Blinky example started."); advertising_start(); // Enter main loop. for (;;) { idle_state_handle(); } } /** * @} */

How to update advertised TX power?

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