After configured internal low frequency clock source,advertising stop but saadc still working

[zaki_fighting]

The program flow of the slave is to sample the analog signal source through the saadc and then send it to the host through the nus.
When debugging on nrf52dk, configure the chip to xtal mode and the program can run smoothly. But when the chip is configured as a 32.768k internal low-frequency clock source RC, after each reset, the broadcast signal appears for a while and disappears, but the saadc sampling continues to run. Why?
The strange thing is that the first run after programming the program is normal.

[zaki_fighting]

Thank you for your advice. And I have found many deficiencies in me, and I will try to improve them next.

Because in the original code, I used non-blocking sampling mode. Under Simonr's suggestion, I changed to blocking mode and commented out the original non-blocking mode code, and did not use the code for switching mode.

As for adc_timer_handle function,

In blocking mode, I use it to start adc sampling periodically, and send the sampling results to the host through the nus after the sampling is completed.
In non-blocking mode, this piece of code takes effect when the adc sampling generates the NRF_DRV_SAADC_EVT_DONE callback event. At this time, adc_timer is only used to periodically trigger sampling in non-blocking mode.

[Karl Ylvisaker]

zaki_fighting said:

Thank you for your advice. And I have found many deficiencies in me, and I will try to improve them next.

No problem at all, I am happy to hear that you found my comments helpful and glad that you want to make the improvements! :) 

zaki_fighting said:

In non-blocking mode, this piece of code takes effect when the adc sampling generates the NRF_DRV_SAADC_EVT_DONE callback event. At this time, adc_timer is only used to periodically trigger sampling in non-blocking mode.

Thank you for clarifying on this - this is what I thought you were doing, but I had to ask to be sure. Especially some of the commented out code made me unsure, but now it is much clearer!
So then, let us continue with the debugging of the non-blocking mode. You may then remove the timer and timer handler entirely while we do so, as suggested in my previous comment.

If you want the saadc sampling to happen periodically, without requiring CPU interaction, then I suggest that you change your non-blocking implementation to match that of the SAADC example from the SDK. The SAADC example shows how to implement the sample task triggering by a timer through PPI, which does not require the CPU to intervene for each sampling. In your current code, I cant see how you actually trigger the periodic samplings, since you do not intend to keep the saadc timer callback.
Could you share with me you loggers output, when you run your non-blocking saadc sampling code?

If you make the improvements to the code, feel free to share the code here again so I may take a look at the improved version! :) 

Looking forward to resolving this issue together!

Best regards,
Karl

[zaki_fighting]

Hi, I am sorry for replying to you too late.

I have improved my code, and used ppi to trigger saadc sampling.But I meet new problem.The log as follows.

00> <debug> nrf_sdh: State request: 0x00000000
00> <debug> nrf_sdh: State change: 0x00000000
00> <debug> nrf_sdh: State change: 0x00000001
00> <debug> nrf_sdh_ble: RAM starts at 0x20002A00
00> <info> app: Debug logging for advertising started.
00> <error> app: SOFTDEVICE: INVALID MEMORY ACCESS

And the new code as follows:

/**
 * Copyright (c) 2014 - 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.
 *
 */
/** @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 <stdbool.h>
#include <stdint.h>
#include <stdio.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 "nrf_ble_qwr.h"
#include "app_timer.h"
#include "ble_nus.h"
#include "app_uart.h"
#include "app_util_platform.h"
#include "app_error.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_delay.h"
#include "boards.h"
#include "bsp_btn_ble.h"
#include "nrf_drv_timer.h"
#include "nrf_drv_saadc.h"
#include "nrf_drv_ppi.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 "nrfx_saadc.h"
#include "nrf_queue.h"

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

#define DEVICE_NAME                     "zgs-nus-test"                               /**< 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_DURATION                18000                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#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. */
#define SAMPLES_IN_BUFFER         			3																						/**< adc buffer size*/

BLE_NUS_DEF(m_nus, 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. */

static const nrf_drv_timer_t m_timer = NRF_DRV_TIMER_INSTANCE(0);
static nrf_ppi_channel_t     m_ppi_channel;
static uint32_t              m_adc_evt_counter;
static nrf_saadc_value_t     m_buffer_pool[2][SAMPLES_IN_BUFFER];										/**<adc sampling value.*/
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}
};

static bool m_saadc_calibrate= false;																								/**< Flag indicating that saadc is calibrating */


/**@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.
 */
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 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 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_evt       Nordic UART Service event.
 */
/**@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 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') ||
                (data_array[index - 1] == '\r') ||
                (index >= m_ble_nus_max_data_len))
            {
                if (index > 1)
                {
                    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_data_send(&m_nus, data_array, &length, m_conn_handle);
                        if ((err_code != NRF_ERROR_INVALID_STATE) &&
                            (err_code != NRF_ERROR_RESOURCES) &&
                            (err_code != NRF_ERROR_NOT_FOUND))
                        {
                            APP_ERROR_CHECK(err_code);
                        }
                    } while (err_code == NRF_ERROR_RESOURCES);
                }

                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 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 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;
    }
}


static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    ble_gap_evt_t const * p_gap_evt = &p_ble_evt->evt.gap_evt;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            NRF_LOG_INFO("Connected. conn_handle: 0x%x",p_gap_evt->conn_handle);
            break;

        case BLE_GAP_EVT_DISCONNECTED:

            NRF_LOG_INFO("Disconnected. conn_handle: 0x%x, reason: 0x%x",
                         p_gap_evt->conn_handle,
                         p_gap_evt->params.disconnected.reason);
            break;

        default:
            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 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 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, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
    APP_ERROR_CHECK(err_code);
}

/**@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 initializing services that will be used by the application.
 */
static void services_init(void)
{
    uint32_t           err_code;
    ble_nus_init_t     nus_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 NUS.
    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 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 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();
    }
}

void adc_timer_handler(nrf_timer_event_t event_type, void * p_context)
{

}
void adc_calibrate(void)
{
    
    ret_code_t err_code =nrf_drv_saadc_calibrate_offset();
		APP_ERROR_CHECK(err_code);
    while (nrf_drv_saadc_is_busy()); 
}

//Hexadecimal to character
uint8_t HexToChar(uint8_t temp)
{
    uint8_t dst;
    if (temp < 10)
		{
        dst = temp + '0';
    }else
		{
        dst = temp -10 +'A';
    }
    return dst;
}
//Convert hexadecimal array to string array
void HexToString(uint8_t *pbDest, uint8_t *pbSrc, uint16_t nLen)
{
    uint16_t i;  
	
    for (i=0; i<nLen; i++)
    {
        pbDest[i*2] = HexToChar(pbSrc[i] / 16);
        pbDest[i*2+1] = HexToChar(pbSrc[i] % 16);
    }
}

void saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{
		ret_code_t err_code;
		uint8_t adc_result[SAMPLES_IN_BUFFER*2],adc_string[SAMPLES_IN_BUFFER*4];
    if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
    {
			NRF_LOG_INFO ("%d evt_done",m_adc_evt_counter);
      if(m_adc_evt_counter%12000==0)
      {
				m_saadc_calibrate = true;                                           																		// Set flag to trigger calibration in main context 
      }
			for(uint8_t i = 0 ;i<p_event->data.done.size;i++)
			{
				adc_result[(i*2)] = p_event->data.done.p_buffer[i] >> 8;
        adc_result[(i*2)+1] = p_event->data.done.p_buffer[i];
			}
			HexToString(adc_string,adc_result,SAMPLES_IN_BUFFER*2);
			if(SAMPLES_IN_BUFFER <= 5)
        {
						uint16_t length = (uint16_t)(SAMPLES_IN_BUFFER*4);
					  ble_nus_data_send(&m_nus, &adc_string[0], &length, m_conn_handle);																	  // send data through nus.
        }	
			if(m_saadc_calibrate == false)
        {
            err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER);            //Set buffer when saadc is not in calibration state. 
            APP_ERROR_CHECK(err_code);
        }
			m_adc_evt_counter++;
	  }
		else if (p_event->type == NRF_DRV_SAADC_EVT_CALIBRATEDONE)
    {                                                                   
        NRF_LOG_INFO("SAADC calibration complete ! \r\n");
				err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0], SAMPLES_IN_BUFFER);             					 		//Set buffer after calibration done. 
				APP_ERROR_CHECK(err_code);
				err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1], SAMPLES_IN_BUFFER);             	 				 	 //Need to setup both buffers, as they were both removed with the call to nrf_drv_saadc_abort before calibration.
				APP_ERROR_CHECK(err_code);			
		}
}
void BLE_saadc_init(void)
{
			ret_code_t err_code;
			nrf_drv_saadc_config_t saadc_config;
			saadc_config.low_power_mode = true;                                                 
			saadc_config.resolution = NRF_SAADC_RESOLUTION_10BIT;                                
			saadc_config.oversample = NRF_SAADC_OVERSAMPLE_2X;                                   
			saadc_config.interrupt_priority = APP_IRQ_PRIORITY_LOW; 
			
			nrf_saadc_channel_config_t channel_config 	=		
			NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);
      channel_config.burst =  NRF_SAADC_BURST_ENABLED;                                   
			channel_config.gain 			= NRF_SAADC_GAIN1_6;
			err_code = nrf_drv_saadc_init(&saadc_config, saadc_callback);    
			APP_ERROR_CHECK(err_code);
			err_code = nrf_drv_saadc_channel_init(0, &channel_config);
			APP_ERROR_CHECK(err_code);
	
#ifndef  SAADC_BLOCKING 
			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);
#endif
}

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_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    timer_cfg.bit_width = NRF_TIMER_BIT_WIDTH_32;
    err_code = nrf_drv_timer_init(&m_timer, &timer_cfg, adc_timer_handler);
    APP_ERROR_CHECK(err_code);

    /* setup m_timer for compare event every 400ms */
    uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer, 400);
    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_task_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_task_addr);
    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);
}


/**@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);
}


/**@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 Application main function.
 */
int main(void)
{
    // Initialize.
		uart_init();
    log_init();
    timers_init();
    power_management_init();
    ble_stack_init();
		gap_params_init();
		gatt_init();
		services_init();
	  advertising_init();
    conn_params_init();
		NRF_LOG_INFO("Debug logging for advertising started.");
		advertising_start();
		nrf_delay_ms(500);
		BLE_saadc_init();
		saadc_sampling_event_init();
		
    // Start execution.
		
    NRF_LOG_INFO("Debug logging for adc over RTT started.");
	  
    // Enter main loop.
    for (;;)
    {
				if(m_saadc_calibrate == true)
        {
            nrf_drv_saadc_abort();                                  // Abort all ongoing conversions. Calibration cannot be run if SAADC is busy
            adc_calibrate();
            m_saadc_calibrate = false;
        } 
				while(NRF_LOG_PROCESS() != NRF_SUCCESS);
        idle_state_handle();			
    }
}


/**
 * @}
 */

Thank you.

[Karl Ylvisaker]

Hello again, 

zaki_fighting said:

I am sorry for replying to you too late.

No problem at all - we'll continue this whenever you have the time.

zaki_fighting said:

I have improved my code, and used ppi to trigger saadc sampling

Great work, I am happy to see that! The code looks a lot better already, well done! :) 

zaki_fighting said:

But I meet new problem.The log as follows.

In your ble_stack_init function you pass the ram start address 0 to the nrf_sdh_ble_default_cfg_set function - this is not a valid application start address, since the SoftDevice is present. Please change this to the value suggested in the log, RAM starts at 0x2002A00, and see if this resolves the error.

Best regards,
Karl

[zaki_fighting]

Hi, I changed my code as follows,but it didn't work. And the uart log never changed.

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 = 0x20002A00;
    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);
}

And the option for target setup in keil as follows:

 

log as follows:

(it seems that the main program has reached the step:

NRF_LOG_INFO("Debug logging for advertising started."); )

00> <debug> nrf_sdh: State request: 0x00000000
00> <debug> nrf_sdh: State change: 0x00000000
00> <debug> nrf_sdh: State change: 0x00000001
00> <debug> nrf_sdh_ble: RAM starts at 0x20002A00
00> <info> app: Debug logging for advertising started.
00> <error> app: SOFTDEVICE: INVALID MEMORY ACCESS

Looking forward to your reply.