Try to transfert ADC sampling signal by BLE.

RE: Try to transfert ADC sampling signal by BLE.

merlin chendjou — Tue, 06 Aug 2019 16:41:16 GMT

Dear sir,

After synchronizing the samples signal, I would like to send them to my ble central.

To test the transfer, I set up the device code below, I want to call a timer every 4ms to transfer 64 bytes to ble central so i use the example examples / ble_central / ble_app_uart_c for data recovery.

I modified the code to configure ATT MTU = 244, gatt data len = 244, PHY update 2MBPS. To ensure synchronization, the module ble_central toggle the LED at each reception.

Problem: I notice that I have a synchronization problem for transfers below 30ms. How can I solve this problem?

Thanks in advance for your answer.

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 * Copyright (c) 2016 - 2018, Nordic Semiconductor ASA
 *
 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without modification,
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 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
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 *    such product, must reproduce the above copyright notice, this list of
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 *    contributors may be used to endorse or promote products derived from this
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 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
/**@cond To Make Doxygen skip documentation generation for this file.
 * @{
 */

#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>


#include "sdk_config.h"
#include "nordic_common.h"
#include "nrf.h"
#include "ble.h"
#include "ble_gatt.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_conn_params.h"
#include "nrf_sdh.h"
#include "nrf_sdh_soc.h"
#include "nrf_sdh_ble.h"
#include "nrf_ble_qwr.h"
#include "app_timer.h"
#include "nrf_ble_gatt.h"
#include "app_util_platform.h"
#include "nrf_gpio.h"

#include "ble_srv_common.h"
#include "bsp_btn_ble.h"
#include "app_error.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_ble_scan.h"
#include "nrf_drv_i2s.h"
#include "app_uart.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include "nrf_delay.h"
#include "saadc_service.h"
#include "sdt_sample_transfer_service.h"
#include "ble_advertising.h"
#include "ble_nus_c.h"

APP_TIMER_DEF(m_sample_delay_timer_id);

#if defined (UART_PRESENT)
#include "nrf_uart.h"
#endif
#if defined (UARTE_PRESENT)
#include "nrf_uarte.h"
#endif


#define MAIN_DEBUG
#ifdef MAIN_DEBUG
#define DEBUG(x,y...) printf ("(%s:%d) " x "\n", __func__ , __LINE__,  ## y)
#else
#define DEBUG(x,y...)
#endif


#define UART_TX_BUF_SIZE                256                                         /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE                256                                         /**< UART RX buffer size. */

#define DATA_LENGTH_DEFAULT             27                                              /**< The stack default data length. */
#define DATA_LENGTH_MAX                 251                                             /**< The stack maximum data length. */

#define CONN_INTERVAL_DEFAULT           (uint16_t)(MSEC_TO_UNITS(7.5, UNIT_1_25_MS))    /**< Default connection interval used at connection establishment by central side. */

#define CONN_INTERVAL_MIN               (uint16_t)(MSEC_TO_UNITS(7.5, UNIT_1_25_MS))    /**< Minimum acceptable connection interval, in units of 1.25 ms. */
#define CONN_INTERVAL_MAX               (uint16_t)(MSEC_TO_UNITS(500, UNIT_1_25_MS))    /**< Maximum acceptable connection interval, in units of 1.25 ms. */
#define CONN_SUP_TIMEOUT                (uint16_t)(MSEC_TO_UNITS(4000,  UNIT_10_MS))    /**< Connection supervisory timeout (4 seconds). */
#define SLAVE_LATENCY                   0                                               /**< Slave latency. */

#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                       /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                      /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */

#define DEAD_BEEF                       0xDEADBEEF                                  /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */



#define CONNECTED_LED                    BSP_BOARD_LED_0
#define TEST_LED                       BSP_BOARD_LED_1

#define APP_BLE_CONN_CFG_TAG            1                                           /**< A tag identifying the SoftDevice BLE configuration. */

#define NUS_SERVICE_UUID_TYPE           BLE_UUID_TYPE_VENDOR_BEGIN                  /**< UUID type for the Nordic UART Service (vendor specific). */

#define APP_BLE_OBSERVER_PRIO           3                                           /**< Application's BLE observer priority. You shouldn't need to modify this value. */

#define APP_ADV_INTERVAL                64                                          /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */

#define APP_ADV_DURATION                18000                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#define SAMPLE_TEST_DELAY  APP_TIMER_TICKS(8)  

extern uint32_t       *mp_block_to_fill;

BLE_ITS_DEF(m_its, NRF_SDH_BLE_TOTAL_LINK_COUNT);                                   /**< BLE NUS service instance. */
NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
NRF_BLE_QWR_DEF(m_qwr);                                                             /**< Context for the Queued Write module.*/
BLE_ADVERTISING_DEF(m_advertising);                                                 /**< Advertising module instance. */

NRF_BLE_SCAN_DEF(m_scan);     


static uint8_t                          m_new_command_received = 0;
static uint8_t                          m_new_resolution, m_new_phy;
//static arducam_mini_2mp_init_t          m_camera_init;

static bool                             m_stream_mode_active = false;

static ble_its_ble_params_info_t        m_ble_params_info = {20, 50, 1, 1};

static uint16_t   m_conn_handle          = BLE_CONN_HANDLE_INVALID;                 /**< Handle of the current connection. */
static uint16_t   m_ble_its_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - 3;            /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */
static ble_uuid_t m_adv_uuids[]          =                                          /**< Universally unique service identifier. */
{
    {BLE_UUID_ITS_SERVICE, NUS_SERVICE_UUID_TYPE}
};


board_role_t  m_board_role; 


			// command type
enum {CMD_NO_COMMAND = 0,
    	CMD_COMMAND,
	    CMD_SENSAMP,
		  CMD_DISABLE_MEAS, 
	    CMD_ENABLE_MEASURE,
	    CMD_SAMPLE_RATE,
      CMD_FLTER_CONFIG, 
      CMD_FILTER_TYPE, 
	    CMD_BYPASS, 
	    CMD_GET_BATT_VOLTAGE, 
	    CMD_GET_BATT_CURRENT, 
	    CMD_GET_BATT_PERCENT,
	    CMD_SAMPLES_XFER
};

static char const m_target_periph_name[] = DEVICE_NAME;

			static ble_uuid_t const m_nus_uuid =
{
    .uuid = BLE_UUID_NUS_SERVICE,
    .type = NUS_SERVICE_UUID_TYPE
};



#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(15, UNIT_1_25_MS)             /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(15, UNIT_1_25_MS)             /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */
#define SLAVE_LATENCY                   0                                           /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */
#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                       /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                      /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */


/**@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 analyse
 *          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 initializing the timer module.
 */
static void timers_init(void)
{
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
}



/**@brief Function for starting scanning. */
static void scan_start(void)
{
    ret_code_t ret;

    ret = nrf_ble_scan_start(&m_scan);
    APP_ERROR_CHECK(ret);

   // ret = bsp_indication_set(BSP_INDICATE_SCANNING);
  //  APP_ERROR_CHECK(ret);
}




/**@brief Function for initializing the timer.
 *
 * @details Initializes the timer module. This creates and starts application timers.
 */
static void timer_init(void)
{
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
}





/**@brief Function for handling Queued Write module errors.
 *
 * @details A pointer to this function is passed to each service that may need to inform the
 *          application about an error.
 *
 * @param[in]   nrf_error   Error code that contains information about what went wrong.
 */
static void nrf_qwr_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}



static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    uint32_t err_code;

	
    switch (p_ble_evt->header.evt_id)
    {
			DEBUG("=> 0x%x", p_ble_evt->header.evt_id);
        case BLE_GAP_EVT_CONNECTED:
            DEBUG("Connected");
				    bsp_board_led_on(CONNECTED_LED);
//            err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
//            APP_ERROR_CHECK(err_code);
            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);
            break;

        case BLE_GAP_EVT_DISCONNECTED:
            DEBUG("Disconnected");
				    bsp_board_led_off(CONNECTED_LED);
            // LED indication will be changed when advertising starts.
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            break;
				
	      case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
        {
            DEBUG("PHY update request 2MBPS.");
            ble_gap_phys_t const phys =
            {
                BLE_GAP_PHY_2MBPS,
                BLE_GAP_PHY_2MBPS,
            };
            err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
            APP_ERROR_CHECK(err_code);
        } 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_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.
            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.
            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;
				
				
        case BLE_GAP_EVT_CONN_PARAM_UPDATE:
        {
            uint16_t max_con_int = p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params.max_conn_interval;
            uint16_t min_con_int = p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params.min_conn_interval;

            m_ble_params_info.con_interval = max_con_int;
           // ble_its_ble_params_info_send(&m_its, &m_ble_params_info);
            DEBUG("Con params updated: CI %i, %i", (int)min_con_int, (int)max_con_int);
        } break;
            		
        case BLE_GAP_EVT_PHY_UPDATE:
            m_ble_params_info.tx_phy = p_ble_evt->evt.gap_evt.params.phy_update.tx_phy;
            m_ble_params_info.rx_phy = p_ble_evt->evt.gap_evt.params.phy_update.rx_phy;    
           // ble_its_ble_params_info_send(&m_its, &m_ble_params_info);
            DEBUG("Phy update: %i, %i", (int)m_ble_params_info.tx_phy, (int)m_ble_params_info.rx_phy);
            break;
        default:
            // No implementation needed.
            //DEBUG("BLE event not handled by app: %i", p_ble_evt->header.evt_id);
            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);
}


/**@brief Function for the GAP initialization.
 *
 * @details This function will set up all the necessary GAP (Generic Access Profile) parameters of
 *          the device. It also sets the permissions and appearance.
 */
static void gap_params_init(void)
{
    uint32_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);
    
#if 0
    ble_gap_addr_t ble_address = {.addr_type = BLE_GAP_ADDR_TYPE_RANDOM_STATIC,
                                  .addr_id_peer = 0,
                                  .addr = {0xC3,0x11,0x99,0x33,0x44,0xFF}};
    err_code = sd_ble_gap_addr_set(&ble_address);
    APP_ERROR_CHECK(err_code);
#endif
}


/**@brief Function for handling events from the GATT library. */
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
    uint32_t data_length;
    if ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
    {
        data_length = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
        //m_ble_params_info.mtu = m_ble_its_max_data_len;
        
        DEBUG("gatt_event: ATT MTU is set to 0x%X (%d)", data_length, data_length);
    }
    else if ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_DATA_LENGTH_UPDATED))
    {
        data_length = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH - 4;
        m_ble_its_max_data_len = data_length;
        m_ble_params_info.mtu = m_ble_its_max_data_len;
        ble_its_ble_params_info_send(&m_its, &m_ble_params_info);
        
        DEBUG("gatt_event: Data len is set to 0x%X (%d)", data_length, data_length);
    }
    //NRF_LOG_DEBUG("ATT MTU exchange completed. central 0x%x peripheral 0x%x",
      //            p_gatt->att_mtu_desired_central,
        //        p_gatt->att_mtu_desired_periph);
}



/**@brief Function for initializing the GATT library. */
static void gatt_init(void)
{
    ret_code_t err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
    APP_ERROR_CHECK(err_code);
	
	    err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
    APP_ERROR_CHECK(err_code);
    
    err_code = nrf_ble_gatt_data_length_set(&m_gatt, BLE_CONN_HANDLE_INVALID, NRF_SDH_BLE_GAP_DATA_LENGTH);
    APP_ERROR_CHECK(err_code);
	
	
}


/**@brief Function for initializing power management.
 */
static void power_management_init(void)
{
    ret_code_t ret;
    ret = nrf_pwr_mgmt_init();
    APP_ERROR_CHECK(ret);
}



void conn_evt_len_ext_set(bool status)
{
    ret_code_t err_code;
    ble_opt_t  opt;

    memset(&opt, 0x00, sizeof(opt));
    opt.common_opt.conn_evt_ext.enable = status ? 1 : 0;

    err_code = sd_ble_opt_set(BLE_COMMON_OPT_CONN_EVT_EXT, &opt);
    APP_ERROR_CHECK(err_code);
}



void data_len_set(uint8_t value)
{
    ret_code_t err_code;
    err_code = nrf_ble_gatt_data_length_set(&m_gatt, BLE_CONN_HANDLE_INVALID, value);
    APP_ERROR_CHECK(err_code);

}



/**@brief Function for initializing the nrf log module.
 */
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 handling an event from the Connection Parameters Module.
 *
 * @details This function will be called for all events in the Connection Parameters Module
 *          which 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)
{
    switch(p_evt->evt_type)
    {
        case BLE_CONN_PARAMS_EVT_SUCCEEDED:
            break;
            
        case BLE_CONN_PARAMS_EVT_FAILED:
            //err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
            //APP_ERROR_CHECK(err_code);
            NRF_LOG_ERROR("Conn params failed. Keep the connection anyway..");
            break;
    }
}


/**@brief Function for handling errors from the Connection Parameters module.
 *
 * @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)
{
    uint32_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)
{
    uint32_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
    APP_ERROR_CHECK(err_code);
}



/**@brief Function for handling advertising events.
 *
 * @details This function will be called for advertising events which are passed to the application.
 *
 * @param[in] ble_adv_evt  Advertising event.
 */
static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
{
    uint32_t err_code;

    switch (ble_adv_evt)
    {
        case BLE_ADV_EVT_FAST:
          //  err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
         //   APP_ERROR_CHECK(err_code);
            break;
        case BLE_ADV_EVT_IDLE:
            DEBUG("BLE_ADV_EVT_IDLE...");
            err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
            APP_ERROR_CHECK(err_code);
            break;
        default:
            break;
    }
}



/**@brief Function for initializing the Advertising functionality.
 */
static void advertising_init(void)
{
    uint32_t               err_code;
    ble_advertising_init_t init;

    memset(&init, 0, sizeof(init));

    init.advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance = false;
    init.advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;

    init.srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.srdata.uuids_complete.p_uuids  = m_adv_uuids;

    init.config.ble_adv_fast_enabled  = true;
    init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout  = APP_ADV_DURATION;
    init.evt_handler = on_adv_evt;

    err_code = ble_advertising_init(&m_advertising, &init);
    APP_ERROR_CHECK(err_code);

    ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}




static void sample_delay_timeout_handler(void * p_context)
{
 uint8_t arraytest[200]; 
	bsp_board_led_invert(TEST_LED);
	ble_its_string_send(&m_its, arraytest, 64);
}


/**@brief   Function for handling app_uart events.
 *
 * @details This function will receive a single character from the app_uart module and append it to
 *          a string. The string will be be sent over BLE when the last character received was a
 *          'new line' '\n' (hex 0x0A) or if the string has reached the maximum data length.
 */
/**@snippet [Handling the data received over UART] */
void uart_event_handle(app_uart_evt_t * p_event)
{
    static uint8_t data_array[100];
    static uint8_t index = 0;
	  uint8_t file_data[10]= {1,3,5,2,35,3,2,14,225,45};
  //  uint32_t       err_code;

    switch (p_event->evt_type)
    {
        case APP_UART_DATA_READY:
            UNUSED_VARIABLE(app_uart_get(&data_array[index]));
            index++;

            if ((data_array[index - 1] == '\n') || (data_array[index - 1] == '\r'))
            {
							 if (index > 1)
                {
                  
									   printf("UART Read(  %s )\n",data_array);
									
										 if( (strstr(data_array, "SCAN") != NULL) )											 
											{			
												//  scan_start();
																	
											}			
											
										  if( (strstr(data_array, "DISCONNECT") != NULL) )											 
											{			
												          ret_code_t err_code;
												err_code = sd_ble_gap_disconnect(m_advertising.adv_handle , BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);

												if (err_code != NRF_SUCCESS)
												{
														DEBUG("sd_ble_gap_disconnect() failed: 0x%0x.", err_code);
                            }
																	
											}	

										 if( (strstr(data_array, "TESTXFER") != NULL) )											 
											{			
												 DEBUG("Xfert file.");
												  ble_its_string_send(&m_its, &file_data[0], sizeof(file_data));
																	
											}	

	
										 if( (strstr(data_array, "FILE") != NULL) )											 
											{			
												  ble_its_string_send(&m_its, data_array, strlen(data_array));
																	
											}												

											
										if( (strstr(data_array, "START") != NULL) )											 
											{			
												  	app_timer_start(m_sample_delay_timer_id, SAMPLE_TEST_DELAY, NULL);	
																	
											}	
											
//										else if( ( m_board_role == SDT_SENSOR_ROLE && (strstr(data_array, "START") != NULL) ))
//											{
//												//test_begin();		 			
//											}			

//										else if( ( m_board_role == SDT_RECIEVER_ROLE && (strstr(data_array, "TESTXFER") != NULL) ))
//											{
//												//reciever_params_info_send(&m_amts); 			
//											}		
											
											
											
											
//										else if( strstr(data_array, "STOP") != NULL)										
//											stop_transmission(); 
										
                }

                index = 0;
							
							      //  m_run_test = true;
                   //  test_run();
            }
            break;

        case APP_UART_COMMUNICATION_ERROR:
            APP_ERROR_HANDLER(p_event->data.error_communication);
            break;

        case APP_UART_FIFO_ERROR:
            APP_ERROR_HANDLER(p_event->data.error_code);
            break;

        default:
            break;
    }
}




/**@snippet [Handling the data received over UART] */


/**@brief  Function for initializing the UART module.
 */
/**@snippet [UART Initialization] */
static void uart_init(void)
{
    uint32_t                     err_code;
    app_uart_comm_params_t const comm_params =
    {
        .rx_pin_no    = RX_PIN_NUMBER,
        .tx_pin_no    = TX_PIN_NUMBER,
        .rts_pin_no   = RTS_PIN_NUMBER,
        .cts_pin_no   = CTS_PIN_NUMBER,
        .flow_control = APP_UART_FLOW_CONTROL_DISABLED,
        .use_parity   = false,
#if defined (UART_PRESENT)
        .baud_rate    = NRF_UART_BAUDRATE_115200
#else
        .baud_rate    = NRF_UARTE_BAUDRATE_115200
#endif
    };

    APP_UART_FIFO_INIT(&comm_params,
                       UART_RX_BUF_SIZE,
                       UART_TX_BUF_SIZE,
                       uart_event_handle,
                       APP_IRQ_PRIORITY_LOWEST,
                       err_code);
    APP_ERROR_CHECK(err_code);
}
/**@snippet [UART Initialization] */




/**@brief Function for handling the data from the ITS Service.
 *
 * @details This function will process the data received from the ITS BLE Service.
 *
 * @param[in] p_its    ITS Service structure.
 * @param[in] p_data   Data received.
 * @param[in] length   Length of the data.
 */
/**@snippet [Handling the data received over BLE] */
static void its_data_handler(ble_its_t * p_its, uint8_t const * p_data, uint16_t length)
{
	bsp_board_led_invert(TEST_LED);
	//DEBUG("Recieve %d, %d\n", p_data[0],length); 
    switch(p_data[0])
    {
//        // Take picture
//        case APP_CMD_SINGLE_CAPTURE:
//        case APP_CMD_SEND_BLE_PARAMS:
//            m_new_command_received = p_data[0];
//            break;
//        
//        case APP_CMD_START_STREAM:
//            m_stream_mode_active = true;
//            m_new_command_received = p_data[0];
//            break;

//        case APP_CMD_STOP_STREAM:
//            m_stream_mode_active = false;
//            m_new_command_received = p_data[0];
//            break;
//        
//        case APP_CMD_CHANGE_RESOLUTION:
//            m_new_command_received = APP_CMD_CHANGE_RESOLUTION;
//            m_new_resolution = p_data[1];
//            break;
//        
//        case APP_CMD_CHANGE_PHY:
//            m_new_command_received = APP_CMD_CHANGE_PHY;
//            m_new_phy = p_data[1];
//            break;
//        
//        default: 
//            NRF_LOG_ERROR("Unknown command!!");
//            break;
    }
}
/**@snippet [Handling the data received over BLE] */



/**@brief Function for initializing services that will be used by the application.
 */
static void services_init(void)
{
    uint32_t           err_code;
    ble_its_init_t     its_init;
    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 ITS.
    memset(&its_init, 0, sizeof(its_init));

    its_init.data_handler = its_data_handler;

    err_code = ble_its_init(&m_its, &its_init);
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for initializing the LEDs.
 *
 * @details Initializes all LEDs used by the application.
 */
static void leds_init(void)
{
    bsp_board_init(BSP_INIT_LEDS);
}

/**@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)
{
//    while(NRF_LOG_PROCESS());
//    sd_app_evt_wait();
	    UNUSED_RETURN_VALUE(NRF_LOG_PROCESS());
    nrf_pwr_mgmt_run();
	
}



int main(void)
{
    // Initialize.
    ble_gap_phys_t gap_phys_settings;		
	  uart_init();
   // log_init();
    leds_init();
    timer_init();
    //counter_init();
	  gpio_init(); 
	  m_board_role = get_sdt_boardrole(); 
   // buttons_init();
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
	  services_init();
	  advertising_init(); 
	  conn_params_init(); 
	  sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);
	
	//   scan_init();  // RECIEVER
	
	advertising_start(); 
	
	DEBUG("Start test !!!"); 
	
 app_timer_create(&m_sample_delay_timer_id,
                            APP_TIMER_MODE_REPEATED,
                            sample_delay_timeout_handler);
	



										
										
	//  sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);  
   
    for (;;)
    {
	
			idle_state_handle();
        
			
			
    }
}

/**
 * @}
 */

RE: Try to transfert ADC sampling signal by BLE.

awneil — Tue, 23 Jul 2019 10:56:48 GMT

So if your question is now resolved, please verify the answer:

RE: Try to transfert ADC sampling signal by BLE.

merlin chendjou — Tue, 23 Jul 2019 10:51:01 GMT

Dear sir,

Please do not consider my last message.
I found the error and corrected.

Thanks,

RE: Try to transfert ADC sampling signal by BLE.

merlin chendjou — Mon, 22 Jul 2019 17:43:57 GMT

Dear Sir,

I thank you for this remark. I can indeed see that SAADC Callback is called after 100 samples since SAMPLE_IN_BUFFER is set to 100.

To make sure that I get into the callback, I toggle a pin out of the chip to ensure that the duration of taking measurements is constant and therefore my samples are synchronized.

If I activate a Bluetooth transmission in parallel, during the transfer, I can notice a timing error in the SAADC Callback . There is therefore an error in the discretization of my signal.
How can I set a priority on my ADC timer or correct the timing problem when the handles on Bluetooth events are called ?

RE: Try to transfert ADC sampling signal by BLE.

haakonsh — Mon, 15 Jul 2019 13:32:10 GMT

In your callback:

// set buffers
err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, 1);
APP_ERROR_CHECK(err_code);

Set the length to SAMPLES_IN_BUFFER and you should be good.

RE: Try to transfert ADC sampling signal by BLE.

merlin chendjou — Thu, 11 Jul 2019 18:51:30 GMT

I understood that I could initialize the Buffer size to 200 samples by changing define SAMPLES_IN_BUFFER. What I do not understand is how to configure my sampling frequency at 16kHz to have a Callback every 12.5ms.

In order to perform the tests, I set the sampling time to 125us (8kHz) with a SAMPLES_IN_BUFFER 200. According to the code below, I hoped that my Callback would be called every 25mS. I can see that my Callback is called every 125uS and I do not understand.

Please see the source code below :

#define SAADC_SAMPLE_RATE		        125                                         /**< SAADC sample rate in us. */      
#define SAMPLES_IN_BUFFER 200 


void saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{
    if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
    {
        ret_code_t err_code;
        float adc_value,adc_value_filered;
        uint8_t value[2];
        uint8_t bytes_to_send;
     
        // set buffers
        err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, 1);
        APP_ERROR_CHECK(err_code);
						
			  bsp_board_led_invert(PROGRESS_LED);
 
    }
}



void saadc_sampling_event_init(void)
{
    ret_code_t err_code;
    err_code = nrf_drv_ppi_init();
    APP_ERROR_CHECK(err_code);
    
    nrf_drv_timer_config_t timer_config = NRF_DRV_TIMER_DEFAULT_CONFIG;
  //  timer_config.frequency = NRF_TIMER_FREQ_31250Hz;
	  timer_config.frequency = NRF_TIMER_FREQ_1MHz;
    err_code = nrf_drv_timer_init(&m_timer, &timer_config, timer_handler);
    APP_ERROR_CHECK(err_code);

    /* setup m_timer for compare event */
    uint32_t ticks = nrf_drv_timer_us_to_ticks(&m_timer,SAADC_SAMPLE_RATE);
    nrf_drv_timer_extended_compare(&m_timer, NRF_TIMER_CC_CHANNEL0, ticks, NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, false);
    nrf_drv_timer_enable(&m_timer);

    uint32_t timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&m_timer, NRF_TIMER_CC_CHANNEL0);
    uint32_t saadc_sample_event_addr = nrf_drv_saadc_sample_task_get();

    /* setup ppi channel so that timer compare event is triggering sample task in SAADC */
    err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel);
    APP_ERROR_CHECK(err_code);
    
    err_code = nrf_drv_ppi_channel_assign(m_ppi_channel, timer_compare_event_addr, saadc_sample_event_addr);
    APP_ERROR_CHECK(err_code);
}


void saadc_init(void)
{
    ret_code_t err_code;
    nrf_drv_saadc_config_t saadc_config = NRF_DRV_SAADC_DEFAULT_CONFIG;
    saadc_config.resolution = NRF_SAADC_RESOLUTION_12BIT;
	

    err_code = nrf_drv_saadc_init(&saadc_config, saadc_callback);
    APP_ERROR_CHECK(err_code);

	    //Configure SAADC channel
    nrf_saadc_channel_config_t config =
        NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN0);                           //Disable pulldown resistor on the input pin
    err_code = nrf_drv_saadc_channel_init(0, &config);
    APP_ERROR_CHECK(err_code);

	
    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0],SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);   
    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1],SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);
}


void saadc_sampling_event_enable(void)
{
    ret_code_t err_code = nrf_drv_ppi_channel_enable(m_ppi_channel);
    APP_ERROR_CHECK(err_code);
}

RE: Try to transfert ADC sampling signal by BLE.

haakonsh — Thu, 11 Jul 2019 11:11:53 GMT

If you just set your buffer size to 200 samples, you'll get a callback once those are done. The saadc example uses the define SAMPLES_IN_BUFFER or something similar to set the buffer sizes.

RE: Try to transfert ADC sampling signal by BLE.

merlin chendjou — Wed, 10 Jul 2019 12:18:07 GMT

Hello,

Thanks for your reply.

I changed the callback time to a few milliseconds and the problem is solved. I just did a test by changing the Callback timer to 10ms and it works.

If I want to sample my signal at 16ksps, so with a buffer of 200 samples I can set a Callback every 12.5ms. Can you help me configure my timer and the SAADC ?

Best regards,

RE: Try to transfert ADC sampling signal by BLE.

awneil — Wed, 10 Jul 2019 09:17:49 GMT

How to properly post source code:

RE: Try to transfert ADC sampling signal by BLE.

haakonsh — Wed, 10 Jul 2019 07:53:04 GMT

I have not found a root cause, but I did find something that will be an issue.

You're using SAADC buffer sizes of 1, ie. one sample taken and processed every 80µs, and that's not possible with a BLE stack running. You need to use larger buffer sizes for your ADC sampling and process them far less often.
What will happen now is that the SoftDevice will block the SAADC driver's IRQ from executing whenever there's some BLE activity or stack processing to be done, and your SAADC sampling will halt.

I suggest you double buffer your SAADC buffers, like our example does, and choose a size so that you will get a callback every few milliseconds (the longer the better).

This issue might be related to your original issue, what IRQ priority have you set the SAADC driver to use?

RE: Try to transfert ADC sampling signal by BLE.

merlin chendjou — Tue, 09 Jul 2019 15:46:18 GMT

when the event to activate the timer for sampling SAADC is enabled (saadc_sampling_event_enable() ) , AMT server event handler is no longer executes.

You must disable the timer event for sampling SAADC, so the AMT server event works properly.

Best regards,

RE: Try to transfert ADC sampling signal by BLE.

haakonsh — Tue, 09 Jul 2019 12:20:19 GMT

"If I enable sampling and data transfer by BLE, the Bluetooth stack no longer works (the pairing does not run). I tried to use SAADC sampling using other Timers and the problem is not solved.I notice that the timer activation generates a conflict with the bluetooth stack."

We need some details