SPI BLE receive wrong values via UART and BLE

[Christoph_I]

Hey guys,

I'm working with a Laird BL652-DVK (nrF 52832 - chip), Nordic SDK v.14.2.0 and SES (Segger Embedded Studio v.4.30). My goal is to send datas from sensor (accelerometer LIS3DH) via bluetooth to my phone. I get via spi the datas from sensor.

At first I tested the examples spim, uart and ble_app_uart separatly and all examples worked. But now I try to combine my modified example spim with unmodified example ble_app_uart and get the wrong "WHO_AM_I" values both via UART (Termite v3.4) and via BLE (to my phone, app: nRF Connect). (My modified spim code is working too.)

Via UART I get instead of 0x33 (default value for WHO_AM_I) another value. Via Bluetooth I get instead of 0x33 the value 0x3. I think there is something wrong with my code...

Here is my code:

/**
 * Copyright (c) 2014 - 2017, 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.
 * 
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 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    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
 *    software without specific prior written permission.
 * 
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 * 
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 *    engineered, decompiled, modified and/or disassembled.
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 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
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 * 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.
 * 
 */
/** @file
 *
 * @defgroup ble_sdk_uart_over_ble_main main.c
 * @{
 * @ingroup  ble_sdk_app_nus_eval
 * @brief    UART over BLE application main file.
 *
 * This file contains the source code for a sample application that uses the Nordic UART service.
 * This application uses the @ref srvlib_conn_params module.
 */



#include <stdint.h>
#include <string.h>
#include "nordic_common.h"
#include "nrf.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_params.h"
#include "nrf_sdh.h"
#include "nrf_sdh_soc.h"
#include "nrf_sdh_ble.h"
#include "nrf_ble_gatt.h"
#include "app_timer.h"
#include "ble_nus.h"
#include "app_uart.h"
#include "app_util_platform.h"
#include "bsp_btn_ble.h"

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

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include "nrf_drv_spi.h"  //spi header
#include "nrf_delay.h"  //delay header

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

#define APP_FEATURE_NOT_SUPPORTED       BLE_GATT_STATUS_ATTERR_APP_BEGIN + 2        /**< Reply when unsupported features are requested. */

#define DEVICE_NAME                     "Nordic_UART"                               /**< Name of device. Will be included in the advertising data. */
#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_TIMEOUT_IN_SECONDS      180                                         /**< The advertising timeout (in units of seconds). */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(20, UNIT_1_25_MS)             /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(75, 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. */

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

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


BLE_NUS_DEF(m_nus);                                                                 /**< BLE NUS service instance. */
NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
BLE_ADVERTISING_DEF(m_advertising);                                                 /**< Advertising module instance. */

static uint16_t   m_conn_handle          = BLE_CONN_HANDLE_INVALID;                 /**< Handle of the current connection. */
static uint16_t   m_ble_nus_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_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}
};
//spi
#define SPI_INSTANCE  0 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
static volatile bool spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. */
uint8_t read_data[2]; //2-byte receive array, 2nd byte will contain id

//accel input register
uint8_t LIS3DH_CTRL_REG1[] = {0x20, 0x47}; //all axes, normal, 50Hz
uint8_t LIS3DH_CTRL_REG2[] = {0x21, 0x00}; //no highpass filter
uint8_t LIS3DH_CTRL_REG3[] = {0x22, 0x00}; //no interrupts
uint8_t LIS3DH_CTRL_REG4[] = {0x23, 0x00}; //all defaults  
uint8_t LIS3DH_CTRL_REG5[] = {0x24, 0x00}; //all defaults
uint8_t LIS3DH_CTRL_REG6[] = {0x25, 0x00}; //all defaults

//accel output register
uint8_t LIS3DH_WHO_AM_I_REG[] = {0x80 | 0x0F};  // Set ms bit to perform a read
uint8_t LIS3DH_OUT_X_H[] = {0x80 | 0x29};
uint8_t LIS3DH_OUT_X_L[] = {0x80 | 0x28};
uint8_t LIS3DH_OUT_Y_H[] = {0x80 | 0x2B};
uint8_t LIS3DH_OUT_Y_L[] = {0x80 | 0x2A};
uint8_t LIS3DH_OUT_Z_H[] = {0x80 | 0x2D};
uint8_t LIS3DH_OUT_Z_L[] = {0x80 | 0x2C};




/**@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 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.
 *          Es beschreibt, welche Funktion das Bluetooth-Modul auf der untersten Ebene eruellen muss,
 *          z.B. Verbindungsaufbau, Authentifizierung, Betriebsarten... .
 */
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);
}


/**@brief Function for handling the data from the Nordic UART Service.
 *
 * @details This function will process the data received from the Nordic UART BLE Service and send
 *          it to the UART module.
 *
 * @param[in] p_nus    Nordic UART Service structure.
 * @param[in] p_data   Data to be send to UART module.
 * @param[in] length   Length of the data.
 */
/**@snippet [Handling the data received over BLE] */
static void nus_data_handler(ble_nus_evt_t * p_evt)
{

    if (p_evt->type == BLE_NUS_EVT_RX_DATA)
    {
        uint32_t err_code;

        NRF_LOG_DEBUG("Received data from BLE NUS. Writing data on UART.");
        NRF_LOG_HEXDUMP_DEBUG(p_evt->params.rx_data.p_data, p_evt->params.rx_data.length);

        for (uint32_t i = 0; i < p_evt->params.rx_data.length; i++)
        {
            do
            {
                err_code = app_uart_put(p_evt->params.rx_data.p_data[i]);
                if ((err_code != NRF_SUCCESS) && (err_code != NRF_ERROR_BUSY))
                {
                    NRF_LOG_ERROR("Failed receiving NUS message. Error 0x%x. ", err_code);
                    APP_ERROR_CHECK(err_code);
                }
            } while (err_code == NRF_ERROR_BUSY);
        }
        if (p_evt->params.rx_data.p_data[p_evt->params.rx_data.length-1] == '\r')
        {
            while (app_uart_put('\n') == NRF_ERROR_BUSY);
        }
    }

}
/**@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_nus_init_t nus_init;

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

    nus_init.data_handler = nus_data_handler;

    err_code = ble_nus_init(&m_nus, &nus_init);
    APP_ERROR_CHECK(err_code);
}


/**@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)
{
    uint32_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 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 putting the chip into sleep mode.
 *
 * @note This function will not return.
 */
static void sleep_mode_enter(void)
{
    uint32_t err_code = bsp_indication_set(BSP_INDICATE_IDLE);
    APP_ERROR_CHECK(err_code);

    // Prepare wakeup buttons.
    err_code = bsp_btn_ble_sleep_mode_prepare();
    APP_ERROR_CHECK(err_code);

    // Go to system-off mode (this function will not return; wakeup will cause a reset).
    err_code = sd_power_system_off();
    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:
            sleep_mode_enter();
            break;
        default:
            break;
    }
}


/**@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)
{
    uint32_t err_code;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            NRF_LOG_INFO("Connected");
            err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
            APP_ERROR_CHECK(err_code);
            m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
            break;

        case BLE_GAP_EVT_DISCONNECTED:
            NRF_LOG_INFO("Disconnected");
            // LED indication will be changed when advertising starts.
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            break;

#ifndef S140
        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;
#endif

        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;
#if !defined (S112)
         case BLE_GAP_EVT_DATA_LENGTH_UPDATE_REQUEST:
        {
            ble_gap_data_length_params_t dl_params;

            // Clearing the struct will effectivly set members to @ref BLE_GAP_DATA_LENGTH_AUTO
            memset(&dl_params, 0, sizeof(ble_gap_data_length_params_t));
            err_code = sd_ble_gap_data_length_update(p_ble_evt->evt.gap_evt.conn_handle, &dl_params, NULL);
            APP_ERROR_CHECK(err_code);
        } break;
#endif //!defined (S112)
        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_EVT_USER_MEM_REQUEST:
            err_code = sd_ble_user_mem_reply(p_ble_evt->evt.gattc_evt.conn_handle, NULL);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST:
        {
            ble_gatts_evt_rw_authorize_request_t  req;
            ble_gatts_rw_authorize_reply_params_t auth_reply;

            req = p_ble_evt->evt.gatts_evt.params.authorize_request;

            if (req.type != BLE_GATTS_AUTHORIZE_TYPE_INVALID)
            {
                if ((req.request.write.op == BLE_GATTS_OP_PREP_WRITE_REQ)     ||
                    (req.request.write.op == BLE_GATTS_OP_EXEC_WRITE_REQ_NOW) ||
                    (req.request.write.op == BLE_GATTS_OP_EXEC_WRITE_REQ_CANCEL))
                {
                    if (req.type == BLE_GATTS_AUTHORIZE_TYPE_WRITE)
                    {
                        auth_reply.type = BLE_GATTS_AUTHORIZE_TYPE_WRITE;
                    }
                    else
                    {
                        auth_reply.type = BLE_GATTS_AUTHORIZE_TYPE_READ;
                    }
                    auth_reply.params.write.gatt_status = APP_FEATURE_NOT_SUPPORTED;
                    err_code = sd_ble_gatts_rw_authorize_reply(p_ble_evt->evt.gatts_evt.conn_handle,
                                                               &auth_reply);
                    APP_ERROR_CHECK(err_code);
                }
            }
        } break; // BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST

        default:
            // No implementation needed.
            break;
    }
}


/**@brief Function for the SoftDevice initialization.
 *
 * @details This function 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 handling events from the GATT library. */
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
    if ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
    {
        m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
        NRF_LOG_INFO("Data len is set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
    }
    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. */
void gatt_init(void)
{
    ret_code_t err_code;

    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, 64);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling events from the BSP module. //BSP: Board Support Package to control hardware peripherals interface
 *
 * @param[in]   event   Event generated by button press.
 */
void bsp_event_handler(bsp_event_t event)
{
    uint32_t err_code;
    switch (event)
    {
        case BSP_EVENT_SLEEP:
            sleep_mode_enter();
            break;

        case BSP_EVENT_DISCONNECT:
            err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            if (err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
            break;

        case BSP_EVENT_WHITELIST_OFF:
            if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
            {
                err_code = ble_advertising_restart_without_whitelist(&m_advertising);
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
            }
            break;

        default:
            break;
    }
}



/**@brief   Function for handling spi events.
 */
/**@snippet [Handling the data received over SPI] */
void spi_event_handler(nrf_drv_spi_evt_t const * p_event, void * p_context)
{
    spi_xfer_done = true;
}
/**@snippet [Handling the data received over SPI] */



/**@brief  Function for initializing the spi.
 */
/**@snippet [SPI Initialization] */
void spi_init()
{
    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;  //SPI master driver instance configuration
    spi_config.ss_pin   = 22;
    spi_config.miso_pin = 24;   
    spi_config.mosi_pin = 23;   
    spi_config.sck_pin  = 25;
    spi_config.frequency = NRF_DRV_SPI_FREQ_8M; // data rate: 8 Mbps
    spi_config.mode     = NRF_DRV_SPI_MODE_0;	// SPI mode: SCK active high, sample on leading edge of clock.
    nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL); //Function for initializing the SPI master driver instance
}
/**@snippet [SPI Initialization] */


/**@brief  Function for initializing the LIS3DH.
 */
/**@snippet [LIS3DH Initialization] */
void lis_init() 
{
      nrf_drv_spi_transfer(&spi, LIS3DH_CTRL_REG1, sizeof(LIS3DH_CTRL_REG1), NULL, 0);
      nrf_drv_spi_transfer(&spi, LIS3DH_CTRL_REG2, sizeof(LIS3DH_CTRL_REG2), NULL, 0);
      nrf_drv_spi_transfer(&spi, LIS3DH_CTRL_REG3, sizeof(LIS3DH_CTRL_REG3), NULL, 0);
      nrf_drv_spi_transfer(&spi, LIS3DH_CTRL_REG4, sizeof(LIS3DH_CTRL_REG4), NULL, 0);
      nrf_drv_spi_transfer(&spi, LIS3DH_CTRL_REG5, sizeof(LIS3DH_CTRL_REG5), NULL, 0);
      nrf_drv_spi_transfer(&spi, LIS3DH_CTRL_REG6, sizeof(LIS3DH_CTRL_REG6), NULL, 0);
}
/**@snippet [LIS3DH Initialization] */



/**@brief  Function for boosting drive levels to the outputs (for long wires).
 */
/**@snippet [Boosting drive levels to the outputs] */
void boost_drive_levels()
{
    nrf_gpio_cfg(22,  NRF_GPIO_PIN_DIR_OUTPUT, NRF_GPIO_PIN_INPUT_DISCONNECT, NRF_GPIO_PIN_NOPULL, NRF_GPIO_PIN_H0H1, NRF_GPIO_PIN_NOSENSE);
    nrf_gpio_cfg(23,  NRF_GPIO_PIN_DIR_OUTPUT, NRF_GPIO_PIN_INPUT_DISCONNECT, NRF_GPIO_PIN_NOPULL, NRF_GPIO_PIN_H0H1, NRF_GPIO_PIN_NOSENSE);
    nrf_gpio_cfg(25,  NRF_GPIO_PIN_DIR_OUTPUT, NRF_GPIO_PIN_INPUT_DISCONNECT, NRF_GPIO_PIN_NOPULL, NRF_GPIO_PIN_H0H1, NRF_GPIO_PIN_NOSENSE);
}
/**@snippet [Boosting drive levels to the outputs] */




/**@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[BLE_NUS_MAX_DATA_LEN];
    static uint8_t index = 0;
    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') || (index >= (m_ble_nus_max_data_len)))
            {
                NRF_LOG_DEBUG("Ready to send data over BLE NUS");
                NRF_LOG_HEXDUMP_DEBUG(data_array, index);

                do
                {
                    uint16_t length = (uint16_t)index;
                    err_code = ble_nus_string_send(&m_nus, data_array, &length);
                    if ( (err_code != NRF_ERROR_INVALID_STATE) && (err_code != NRF_ERROR_BUSY) )
                    {
                        APP_ERROR_CHECK(err_code);
                    }
                } while (err_code == NRF_ERROR_BUSY);

                index = 0;
            }
            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,
        .baud_rate    = NRF_UART_BAUDRATE_115200
    };

    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 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_TIMEOUT_IN_SECONDS;

    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);
}


/**@brief Function for initializing buttons and leds.
 *
 * @param[out] p_erase_bonds  Will be true if the clear bonding button was pressed to wake the application up.
 */
static void buttons_leds_init(bool * p_erase_bonds)
{
    bsp_event_t startup_event;

    uint32_t err_code = bsp_init(BSP_INIT_LED | BSP_INIT_BUTTONS, bsp_event_handler);
    APP_ERROR_CHECK(err_code);

    err_code = bsp_btn_ble_init(NULL, &startup_event);
    APP_ERROR_CHECK(err_code);

    *p_erase_bonds = (startup_event == BSP_EVENT_CLEAR_BONDING_DATA);
}


/**@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 placing the application in low power state while waiting for events.
 */
static void power_manage(void)
{
    uint32_t err_code = sd_app_evt_wait();
    APP_ERROR_CHECK(err_code);
}


/**@brief Application main function.
 */
int main(void)
{
    uint32_t err_code;
    bool     erase_bonds;

    // Initialize.
    err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);

    uart_init();
    log_init();

    buttons_leds_init(&erase_bonds);
    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();

    printf("\r\nUART Start!\r\n");
    //NRF_LOG_INFO("UART Start!");
    
    spi_init();

    printf("\r\nSPI init done!\r\n");
    //NRF_LOG_INFO("spi init done!");
    
    nrf_drv_spi_transfer(&spi, LIS3DH_WHO_AM_I_REG, sizeof(LIS3DH_WHO_AM_I_REG), read_data, sizeof(read_data));
    nrf_delay_ms(500);
    printf("WHOAMI: %x\r\n", read_data[1]);   //print 0x33 on Termite (pc terminal) /2nd returned byte is Id); ; 1st returned byte is register address

    uint16_t length = sizeof(read_data);
    ble_nus_string_send(&m_nus, read_data, &length);  //send 0x33 via ble to phone (nRF Connect)

    lis_init();

    boost_drive_levels();
    err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
    APP_ERROR_CHECK(err_code);
    
    while(1)
    {
        nrf_drv_spi_transfer(&spi, LIS3DH_WHO_AM_I_REG, sizeof(LIS3DH_WHO_AM_I_REG), read_data, sizeof(read_data));
        nrf_delay_ms(500);
        printf("WHOAMI: %d\r\n", read_data[1]);           //print 2nd returned byte, which will be Id (0x33); 1st returned byte is register address
        ble_nus_string_send(&m_nus, read_data, &length);  //send 0x33 via ble to phone (nRF Connect)
    }
}


/**
 * @}
 */

Here are the received datas via UART:

I don't understand why I get firstly "0x24" and after it constantly "0x51"..? Because while debugging the first value is 0x24 (same like picture above) and after it constantly 0x33...

Here is the received data via BLE:

I hope, you can help me.

Best regards,

Christoph

[cbd]

I've not looked at your code yet, but points that spring to mind: 0x33 (hex) = 51 decimal = ASCII character '3'. 

If your characteristic is defined as having a string type then nRF Connect will automatically convert it - displaying 3 for 0x33.

… 

Looking at your code in main() your first printf statement formats the value as hex:

printf("WHOAMI: %x\r\n", read_data[1]);

whereas your second printf formats the value as decimal:

printf("WHOAMI: %d\r\n", read_data[1]);

...

I can't see why your first character out is 0x24 ('$'), perhaps you can tell dynamically e.g. in debug.

...

Ah shouldn't this line

 lis_init();

occur before you try to read the spi first time?

[Christoph_I]

Hey cbd,

1)

cbd said:

>>> I've not looked at your code yet, but points that spring to mind: 0x33 (hex) = 51 decimal = ASCII character '3'. 

If your characteristic is defined as having a string type then nRF Connect will automatically convert it - displaying 3 for 0x33.    <<<

You are right, thank you. I forgot such things like ASCII and exact displaying. Also the second printf format wasn't the right, thanks for your attention!

2)

cbd said:

occur before you try to read the spi first time?

 In my modified periphal example spim I have the first printf(...WHO_AM_I...) before lis_init() and this worked... Now I tried out the 1st printf(...WHO_AM_I...) after lis_init() because of your suggestion and now I get 0x33. I don't know where is difference between spim and ble_app_uart but thank you cbd!

3)

I have a further question: to send datas via bluetooth to my phone/pc I need the function ble_nus_string_send() and this function send the data as string. Do you know if there are possibilities to send the datas as hex or decimal values? Or is there only the possibility for me to convert the values ​​manually (by an own function, e.g. convert 0x33 in string/ASCII "33" and give "33" to ble_nus_string_send() )?

[cbd]

You can send non-text (or ASCII) if you wish, as ultimately all data is binary anyway.

Points to bear in mind:

0x00 (or null) is a valid value and as it acts as a string terminator you will need to replace any string handling operators with array handling ones e.g. strlen to determine size of data to send will no longer work.

The Nordic NUS code should support it as :

err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);

treats the data as binary anyway.

The NUS code may require certain terminators such as '\n' or '\r' to determine end of text - so you'll need to check that.

nRF Connect will be expecting to handle the Nordic UART Service data as text. It probably wont handle the data correctly for display, particularly non-printable characters.

You could use the Nordic code as is, but change the service UUID (change the nus_base_uuid ) in this section

// Add a custom base UUID.
    err_code = sd_ble_uuid_vs_add(&nus_base_uuid, &p_nus->uuid_type);
    VERIFY_SUCCESS(err_code);

    ble_uuid.type = p_nus->uuid_type;
    ble_uuid.uuid = BLE_UUID_NUS_SERVICE;

    // Add the service.
    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
                                        &ble_uuid,
                                        &p_nus->service_handle);

[Christoph_I]

Thanks for your great input cbd, you know a lot! But I prefer not to change something in Nordic code so I programmed a function to convert decimal into ASCII. The code is below:

void AxisDec_to_ASCII(uint8_t dec)    
{
    static uint8_t DecArray[3];		
    uint8_t hundred = dec / 100;
    dec -= hundred*100;
    uint8_t ten = dec / 10;	
    dec -= ten * 10;
    uint8_t one = dec;	
	
    DecArray[0] = (hundred+48);	
    DecArray[1] = (ten+48);		
    DecArray[2] = (one+48);		

    uint16_t length = sizeof(DecArray);
    ble_nus_string_send(&m_nus, DecArray, &length);
}

And it works. It convert the datas from dec to hex. What do you think about my function? Any suggestions?

[Christoph_I]

And I have another question: Is there a possibility to query the bluetooth RX buffer? Because I want to implement a send command for sending the sensor datas via ble to my phone. Before the send command it should be not allowed to send anything.

[bjorn-spockeli]

Could you elaborate on this? Is it the phone that should not send any thing to the nRF before the nRF has sent the sensor data?

[Christoph_I]

Hey bjorn-spockeli,

I want something similar to the uart example (../examples/peripheral/uart). Here we see that we close the connection when we send 'q' or 'Q' via uart. (code below)

while (true)
    {
        uint8_t cr;
        while (app_uart_get(&cr) != NRF_SUCCESS);
        while (app_uart_put(cr) != NRF_SUCCESS);

        if (cr == 'q' || cr == 'Q')
        {
            printf(" \r\nExit!\r\n");

            while (true)
            {
                // Do nothing.
            }
        }
    }

I want nearly the same for my modified ble_app_uart. But I don't want to send the quit command 'q' or 'Q' via UART, but via ble. When I press on my phone (nRF Connect) 's' (for start), the nRF sends the sensor data to my phone via ble. When I press 'q' the nRF should stop sending sensor data. And when I press 's' again the nRF send datas again. (pseudocode and photos below)

//initializing
....

uint8_t read_data[2];
uint16_t length = sizeof(read_data);
uint8_t start_stop_command;

start_stop_command = register_which_get_data_via_ble;   //which register I have to read? Or which variable?


while(1):
    switch(start_stop_command)
    {
        case('s' or 'S'):
            //read WHO_AM_I register from lis3dh (example)
            nrf_drv_spi_transfer(&spi, LIS3DH_WHO_AM_I_REG, sizeof(LIS3DH_WHO_AM_I_REG), read_data, sizeof(read_data));     
            while(!spi_xfer_done);
            
            //send WHO_AM_I value (data) via ble to my phone
            ble_nus_string_send(&m_nus, DecArrAxis, &length);
            
            //if pressed 'q' or 'Q': break
            if(register_which_get_data_via_ble == 'q' or register_which_get_data_via_ble == 'Q')
            {
                break;
            }
        
        case('q' or 'Q'):
            //do nothing
            if(register_which_get_data_via_ble == 's' or register_which_get_data_via_ble == 'S')
            {
                break;
            }
    }
}

start command: (app: nRF Connect on my phone)

RX Characteristics --> Value: s

stop command:(app: nRF Connect on my phone)

RX Characteristics --> Value: q

I hope I could explain clearly and precisely.

[bjorn-spockeli]

Hi Christoph, 

If you have are using a modified ble_app_uart example then you're using notifications to send the sensor data to the phone. Notifications can be enabled or disabled by the central device(phone) writing to the CCCD of the characteristic on the slave device. When the CCCD is written to you will get enter the on_write handler in the NUS code. Here the is_notification_enabled flag set to true, see below. 

static void on_write(ble_nus_t * p_nus, ble_evt_t const * p_ble_evt)
{
    ble_gatts_evt_write_t const * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
    ble_nus_evt_t evt;
    evt.p_nus = p_nus;
    if (   (p_evt_write->handle == p_nus->tx_handles.cccd_handle)
        && (p_evt_write->len == 2))
    {
        if (ble_srv_is_notification_enabled(p_evt_write->data))
        {
            p_nus->is_notification_enabled = true;
            evt.type = BLE_NUS_EVT_COMM_STARTED;
        }
        else
        {
            p_nus->is_notification_enabled = false;
            evt.type = BLE_NUS_EVT_COMM_STOPPED;
        }
        p_nus->data_handler(&evt);
    }
    else if (   (p_evt_write->handle == p_nus->rx_handles.value_handle)
             && (p_nus->data_handler != NULL))
    {
        evt.params.rx_data.p_data = p_evt_write->data;
        evt.params.rx_data.length = p_evt_write->len;
        evt.type = BLE_NUS_EVT_RX_DATA;
        p_nus->data_handler(&evt);
    }
    else
    {
        // Do Nothing. This event is not relevant for this service.
    }
}

This flag is checked in ble_nus_string_send, which I assume that you use to send the sensor data. 

uint32_t ble_nus_string_send(ble_nus_t * p_nus, uint8_t * p_string, uint16_t * p_length)
{
    ble_gatts_hvx_params_t hvx_params;

    VERIFY_PARAM_NOT_NULL(p_nus);

    if ((p_nus->conn_handle == BLE_CONN_HANDLE_INVALID) || (!p_nus->is_notification_enabled))
    {
        return NRF_ERROR_INVALID_STATE;
    }

    if (*p_length > BLE_NUS_MAX_DATA_LEN)
    {
        return NRF_ERROR_INVALID_PARAM;
    }

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

    hvx_params.handle = p_nus->tx_handles.value_handle;
    hvx_params.p_data = p_string;
    hvx_params.p_len  = p_length;
    hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;

    return sd_ble_gatts_hvx(p_nus->conn_handle, &hvx_params);
}

As you can see ble_nus_string_send will return NRF_ERROR_INVALID_STATE if is_notification_enabled is false. So you could simply set is_notification_enabled to false when you receive the stop command from nRF Connect on your phone. Alternativly, you can use a timer to trigger the sensor data transmission and use the start/stop signals to start/stop this timer that will call ble_nus_string_send in its timeout handler. 

Best regards

Bjørn