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Getting analog values from different channels using SAADC example

Hello ,

I want to read around 6 analog pins, not necessarily simultaneously. I could afford some delay in between them. i am using nrf52832 dev kit with sdk 15. How do i modify the SAADC example to achieve the same because the example only reads 1 channel. i did found this thread https://devzone.nordicsemi.com/f/nordic-q-a/5561/adc-from-various-pins/19481#19481 which looks similar but i was unable to open the GitHub link provided in the thread. Can you please direct me to the relevant examples. 

Thank you!

Parents
  • Hello,

    It should be fine to measure 6 ADC channels at once.

    Attached is a slightly modified project from the SDK15.0.0\examples\peripheral\saadc example. Only the main.c file is changed. It will measure the 6 pins AIN0 - AIN5, and print the values in the UART log.

    saadc_x_2.zip

     

    Remember that AIN0 is not the same as A0 printed on the PCB. The AINx pins are:

    AIN0 = P0.02
    AIN1 = P0.03
    AIN2 = P0.04
    AIN3 = P0.05
    AIN4 = P0.28
    AIN5 = P0.29


    Best regards,

    Edvin

  • Hello Edvin, that was a great help. I was wondering what would i have to do to take the readings from the other 2 analog pins? it does not have to be at same time. could be after a delay, but how do i take those readings as well?

    Thanks! 

  • Don't see any result, or do you see some results, but not the ones you are looking for? (Does the application stop, or does it print blank values?)

    Please see this post.

    As described, you must use NRF_LOG_FLOAT_MARKER instead of %f when using NRF_LOG to print float values.

    Best regards,

    Edvin

  • Hello Edvin,

    Thanks for the answer. It certainly worked for NRF LOG but how can i see the result in the debug terminal window? In the attached image you can see that i am getting float result in putty terminal but the output of printf() function displays nothing in the debug terminal window. 

    Regards,

  • Also, when i am connecting the analog pin to VDD, its giving me 2.87V. should not I be getting 3.3V by connecting to VDD ?

    Thanks,

  • I see that printf isn't defined by default in the saadc example, so I haven't tested, but have you tested the exact same approach in printf? Just swap NRF_LOG_INFO with printf.

    printf("My float number " NRF_LOG_FLOAT_MARKER "\r\n", NRF_LOG_FLOAT(R));

    BR,

    Edvin

  • Hi Edvin, Hope you are doing good. We just received our prototype boards with nrf52840 processor . Very excited. I have started testing modules of my firmware.

    I am still running into issues while collecting data from analog channels. please look at the attached code snippet and suggest what am i doing wrong. My goal is to store all the values from 5 analog channels into an array adc_value[] and then use these values to do some calculations. But I am facing some weird behavior where I am getting values one by one, sometimes only on channel 1 , sometimes on channel 2 etc. 

    i am simply trying to store 

    AIN0 VALUE -> adc_value[0]

    AIN1 VALUE -> adc_value[1]

    AIN2 VALUE -> adc_value[2]

    AIN3 VALUE -> adc_value[3]

    AIN4 VALUE -> adc_value[4]

    Can you please suggest a better way to do so. 

    Thanks, 

    /**
     * Copyright (c) 2014 - 2018, 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:
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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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     * 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.
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     *    engineered, decompiled, modified and/or disassembled.
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     * 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 "nrf_ble_qwr.h"
    #include "app_timer.h"
    #include "ble_nus.h"
    #include "app_uart.h"
    #include "app_util_platform.h"
    #include "bsp_btn_ble.h"
    #include "nrf_pwr_mgmt.h"
    #include "nrf_drv_timer.h"
    #include "nrf_drv_saadc.h"
    #include "nrf_drv_ppi.h"
    #include "nrf_delay.h"
    #include "nrf_gpio.h "
    #include "boards.h"
    #include "nrf_drv_spi.h"
    #include "app_util_platform.h"
    #include "app_error.h"
    #include "nrf_log.h"
    #include "nrf_log_ctrl.h"
    #include "nrf_log_default_backends.h"
    #include "math.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"
    
    #define APP_BLE_CONN_CFG_TAG            1                                           /**< A tag identifying the SoftDevice BLE configuration. */
    
    #define DEVICE_NAME                     "PULSE_1.0.0"                               /**< 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 SAADC_SAMPLES_IN_BUFFER         5
    
    
    
    float C1 = 0.00100924;
    float C2 = 0.0002378;
    float C3 = 0.000000201920;
    float R,C,R1,R2;
    static uint8_t value[10];
    
    float Res1 = 10000;
    float Res2 = 5100;
    
    
    
    
    static int     m_buffer_pool1[SAADC_SAMPLES_IN_BUFFER ];
    
    
    
    
    #define SAMPLES_IN_BUFFER 3
    static const nrf_drv_timer_t m_timer = NRF_DRV_TIMER_INSTANCE(1);
    static nrf_saadc_value_t     m_buffer_pool[4][SAMPLES_IN_BUFFER];
    static nrf_ppi_channel_t     m_ppi_channel;
    static uint32_t              m_adc_evt_counter;
    
    
    
    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 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}
    };
    
    
    /**@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 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 handling Queued Write Module errors.
     *
     * @details A pointer to this function will be passed to each service which may need to inform the
     *          application about an error.
     *
     * @param[in]   nrf_error   Error code containing information about what went wrong.
     */
    static void nrf_qwr_error_handler(uint32_t nrf_error)
    {
        APP_ERROR_HANDLER(nrf_error);
    }
    
    
    /**@brief Function for handling 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 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 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");
                nrf_gpio_cfg_output(9);
                nrf_gpio_pin_write(9, 1);
                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:
                NRF_LOG_INFO("Disconnected");
                // LED indication will be changed when advertising starts.
                m_conn_handle = BLE_CONN_HANDLE_INVALID;
                break;
    
            case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
            {
                NRF_LOG_DEBUG("PHY update request.");
                ble_gap_phys_t const phys =
                {
                    .rx_phys = BLE_GAP_PHY_AUTO,
                    .tx_phys = BLE_GAP_PHY_AUTO,
                };
                err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
                APP_ERROR_CHECK(err_code);
            } break;
    
            case BLE_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;
    
            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, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling events from the BSP module.
     *
     * @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 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_data_send(&m_nus, data_array, &length, m_conn_handle);
                        if ( (err_code != NRF_ERROR_INVALID_STATE) && (err_code != NRF_ERROR_BUSY) &&
                             (err_code != NRF_ERROR_NOT_FOUND) )
                        {
                            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,
    #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 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 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_LEDS | 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 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)
    {
        UNUSED_RETURN_VALUE(NRF_LOG_PROCESS());
        nrf_pwr_mgmt_run();
    }
    
    
    /**@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);
    }
    
    
    void timer_handler(nrf_timer_event_t event_type, void * p_context)
    {
    
    }
    
    
    
    
    
    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;
            static int adc_value[SAADC_SAMPLES_IN_BUFFER];
            uint16_t T,T1, T2, P1, P2;
           
            uint8_t nus_to_send_array[2];
           
    
            err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAADC_SAMPLES_IN_BUFFER);
            APP_ERROR_CHECK(err_code);
    
            int i;
            NRF_LOG_INFO("ADC event number: %d", (int)m_adc_evt_counter);
    
            for (i = 0; i < SAADC_SAMPLES_IN_BUFFER; i++)
            {
           
                   adc_value[i] = p_event->data.done.p_buffer[i];
                
                                          
            }
    
      
                 
                 R = 10000*((825.5/adc_value[0])-1);
                float logR = log(R);
                 C = C1 + C2*logR + C3*logR*logR*logR;
                T = 1/C;
                T = T - 273.15;
                T = (T*9)/5 + 32;
                T = T/1.009;
    
                 R1 = 10000*((825.5/adc_value[1])-1);
                float logR1 = log(R1);
                 C = C1 + C2*logR1 + C3*logR1*logR1*logR1;
                T1 = 1/C;
                T1 = T1 - 273.15;
                T1 = (T1*9)/5 + 32;
                T1 = T1/1.009;
    
                R2 = 10000*((825.5/adc_value[2])-1);
                float logR2 = log(R2);
                 C = C1 + C2*logR2 + C3*logR2*logR2*logR2;
                T2 = 1/C;
                T2 = T2 - 273.15;
                T2 = (T2*9)/5 + 32;
                T2 = T2/1.009;
    
                P1 = ((adc_value[3] * 3.6)/1024);          
                P1 = P1*(Res2/Res2+Res1);
                P1 = (P1 - 0.5)/4;
                P1 = P1*2;
                P1 = P1*145.038;
    
                P2 = ((adc_value[4] * 3.6)/1024);          
                P2 = P2*(Res2/Res2+Res1);
                P2 = (P2 - 0.5)/4;
                P2 = P2*4;
                P2 = P2*145.038;
    
    
            
            value[0] = (adc_value[0] & 0xFF00) >> 8;
            value[1] = (adc_value[0] & 0x00FF);
            value[2] = (T1 & 0xFF00) >> 8;
            value[3] = (T1 & 0x00FF);
            value[4] = (T2 & 0xFF00) >> 8;
            value[5] = (T2 & 0x00FF);
            value[6] = (P1 & 0xFF00) >> 8;
            value[7] = (P1 & 0x00FF);
            value[8] = (P2 & 0xFF00) >> 8;
            value[9] = (P2 & 0x00FF);
         
    
            m_adc_evt_counter++;
    
            
        }
    }
    
    
    
    
    
    void saadc_init(void)
    {
             ret_code_t err_code;
    
    
             //TEMP 1
             nrf_saadc_channel_config_t channel_0_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN0);
    
             //TEMP2
               nrf_saadc_channel_config_t channel_1_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);
    
             //TEMP3
               nrf_saadc_channel_config_t channel_2_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN2);
    
               nrf_saadc_channel_config_t channel_3_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN3);
    
               nrf_saadc_channel_config_t channel_4_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN4);
    
        err_code = nrf_drv_saadc_init(NULL, saadc_callback);
        APP_ERROR_CHECK(err_code);
    
        err_code = nrf_drv_saadc_channel_init(0, &channel_0_config);
        APP_ERROR_CHECK(err_code);
        err_code = nrf_drv_saadc_channel_init(1, &channel_1_config);
        APP_ERROR_CHECK(err_code);
        err_code = nrf_drv_saadc_channel_init(2, &channel_2_config);
        APP_ERROR_CHECK(err_code);
    
         err_code = nrf_drv_saadc_channel_init(3, &channel_3_config);
        APP_ERROR_CHECK(err_code);
    
         err_code = nrf_drv_saadc_channel_init(4, &channel_4_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);
    
    }
    
    
    
    /**@brief Application main function.
     */
    int main(void)
    {
        bool erase_bonds;
    
        // Initialize.
        uart_init();
        log_init();
        timers_init();
        buttons_leds_init(&erase_bonds);
        power_management_init();
        ble_stack_init();
        gap_params_init();
        gatt_init();
        services_init();
        advertising_init();
        conn_params_init();
        saadc_init();
        advertising_start();
    
    
        
          uint16_t bytes_to_send = 10;
    
        for (;;)
        {     
        
            
            nrf_drv_saadc_sample();
            nrf_delay_ms(2000);  
            ble_nus_data_send(&m_nus, value, &bytes_to_send , m_conn_handle);
    
             idle_state_handle();
        }
    }
    
    
    /**
     * @}
     */
    

Reply
  • Hi Edvin, Hope you are doing good. We just received our prototype boards with nrf52840 processor . Very excited. I have started testing modules of my firmware.

    I am still running into issues while collecting data from analog channels. please look at the attached code snippet and suggest what am i doing wrong. My goal is to store all the values from 5 analog channels into an array adc_value[] and then use these values to do some calculations. But I am facing some weird behavior where I am getting values one by one, sometimes only on channel 1 , sometimes on channel 2 etc. 

    i am simply trying to store 

    AIN0 VALUE -> adc_value[0]

    AIN1 VALUE -> adc_value[1]

    AIN2 VALUE -> adc_value[2]

    AIN3 VALUE -> adc_value[3]

    AIN4 VALUE -> adc_value[4]

    Can you please suggest a better way to do so. 

    Thanks, 

    /**
     * Copyright (c) 2014 - 2018, 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 <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 "nrf_ble_qwr.h"
    #include "app_timer.h"
    #include "ble_nus.h"
    #include "app_uart.h"
    #include "app_util_platform.h"
    #include "bsp_btn_ble.h"
    #include "nrf_pwr_mgmt.h"
    #include "nrf_drv_timer.h"
    #include "nrf_drv_saadc.h"
    #include "nrf_drv_ppi.h"
    #include "nrf_delay.h"
    #include "nrf_gpio.h "
    #include "boards.h"
    #include "nrf_drv_spi.h"
    #include "app_util_platform.h"
    #include "app_error.h"
    #include "nrf_log.h"
    #include "nrf_log_ctrl.h"
    #include "nrf_log_default_backends.h"
    #include "math.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"
    
    #define APP_BLE_CONN_CFG_TAG            1                                           /**< A tag identifying the SoftDevice BLE configuration. */
    
    #define DEVICE_NAME                     "PULSE_1.0.0"                               /**< 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 SAADC_SAMPLES_IN_BUFFER         5
    
    
    
    float C1 = 0.00100924;
    float C2 = 0.0002378;
    float C3 = 0.000000201920;
    float R,C,R1,R2;
    static uint8_t value[10];
    
    float Res1 = 10000;
    float Res2 = 5100;
    
    
    
    
    static int     m_buffer_pool1[SAADC_SAMPLES_IN_BUFFER ];
    
    
    
    
    #define SAMPLES_IN_BUFFER 3
    static const nrf_drv_timer_t m_timer = NRF_DRV_TIMER_INSTANCE(1);
    static nrf_saadc_value_t     m_buffer_pool[4][SAMPLES_IN_BUFFER];
    static nrf_ppi_channel_t     m_ppi_channel;
    static uint32_t              m_adc_evt_counter;
    
    
    
    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 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}
    };
    
    
    /**@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 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 handling Queued Write Module errors.
     *
     * @details A pointer to this function will be passed to each service which may need to inform the
     *          application about an error.
     *
     * @param[in]   nrf_error   Error code containing information about what went wrong.
     */
    static void nrf_qwr_error_handler(uint32_t nrf_error)
    {
        APP_ERROR_HANDLER(nrf_error);
    }
    
    
    /**@brief Function for handling 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 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 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");
                nrf_gpio_cfg_output(9);
                nrf_gpio_pin_write(9, 1);
                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:
                NRF_LOG_INFO("Disconnected");
                // LED indication will be changed when advertising starts.
                m_conn_handle = BLE_CONN_HANDLE_INVALID;
                break;
    
            case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
            {
                NRF_LOG_DEBUG("PHY update request.");
                ble_gap_phys_t const phys =
                {
                    .rx_phys = BLE_GAP_PHY_AUTO,
                    .tx_phys = BLE_GAP_PHY_AUTO,
                };
                err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
                APP_ERROR_CHECK(err_code);
            } break;
    
            case BLE_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;
    
            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, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
        APP_ERROR_CHECK(err_code);
    }
    
    
    /**@brief Function for handling events from the BSP module.
     *
     * @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 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_data_send(&m_nus, data_array, &length, m_conn_handle);
                        if ( (err_code != NRF_ERROR_INVALID_STATE) && (err_code != NRF_ERROR_BUSY) &&
                             (err_code != NRF_ERROR_NOT_FOUND) )
                        {
                            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,
    #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 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 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_LEDS | 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 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)
    {
        UNUSED_RETURN_VALUE(NRF_LOG_PROCESS());
        nrf_pwr_mgmt_run();
    }
    
    
    /**@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);
    }
    
    
    void timer_handler(nrf_timer_event_t event_type, void * p_context)
    {
    
    }
    
    
    
    
    
    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;
            static int adc_value[SAADC_SAMPLES_IN_BUFFER];
            uint16_t T,T1, T2, P1, P2;
           
            uint8_t nus_to_send_array[2];
           
    
            err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAADC_SAMPLES_IN_BUFFER);
            APP_ERROR_CHECK(err_code);
    
            int i;
            NRF_LOG_INFO("ADC event number: %d", (int)m_adc_evt_counter);
    
            for (i = 0; i < SAADC_SAMPLES_IN_BUFFER; i++)
            {
           
                   adc_value[i] = p_event->data.done.p_buffer[i];
                
                                          
            }
    
      
                 
                 R = 10000*((825.5/adc_value[0])-1);
                float logR = log(R);
                 C = C1 + C2*logR + C3*logR*logR*logR;
                T = 1/C;
                T = T - 273.15;
                T = (T*9)/5 + 32;
                T = T/1.009;
    
                 R1 = 10000*((825.5/adc_value[1])-1);
                float logR1 = log(R1);
                 C = C1 + C2*logR1 + C3*logR1*logR1*logR1;
                T1 = 1/C;
                T1 = T1 - 273.15;
                T1 = (T1*9)/5 + 32;
                T1 = T1/1.009;
    
                R2 = 10000*((825.5/adc_value[2])-1);
                float logR2 = log(R2);
                 C = C1 + C2*logR2 + C3*logR2*logR2*logR2;
                T2 = 1/C;
                T2 = T2 - 273.15;
                T2 = (T2*9)/5 + 32;
                T2 = T2/1.009;
    
                P1 = ((adc_value[3] * 3.6)/1024);          
                P1 = P1*(Res2/Res2+Res1);
                P1 = (P1 - 0.5)/4;
                P1 = P1*2;
                P1 = P1*145.038;
    
                P2 = ((adc_value[4] * 3.6)/1024);          
                P2 = P2*(Res2/Res2+Res1);
                P2 = (P2 - 0.5)/4;
                P2 = P2*4;
                P2 = P2*145.038;
    
    
            
            value[0] = (adc_value[0] & 0xFF00) >> 8;
            value[1] = (adc_value[0] & 0x00FF);
            value[2] = (T1 & 0xFF00) >> 8;
            value[3] = (T1 & 0x00FF);
            value[4] = (T2 & 0xFF00) >> 8;
            value[5] = (T2 & 0x00FF);
            value[6] = (P1 & 0xFF00) >> 8;
            value[7] = (P1 & 0x00FF);
            value[8] = (P2 & 0xFF00) >> 8;
            value[9] = (P2 & 0x00FF);
         
    
            m_adc_evt_counter++;
    
            
        }
    }
    
    
    
    
    
    void saadc_init(void)
    {
             ret_code_t err_code;
    
    
             //TEMP 1
             nrf_saadc_channel_config_t channel_0_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN0);
    
             //TEMP2
               nrf_saadc_channel_config_t channel_1_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);
    
             //TEMP3
               nrf_saadc_channel_config_t channel_2_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN2);
    
               nrf_saadc_channel_config_t channel_3_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN3);
    
               nrf_saadc_channel_config_t channel_4_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN4);
    
        err_code = nrf_drv_saadc_init(NULL, saadc_callback);
        APP_ERROR_CHECK(err_code);
    
        err_code = nrf_drv_saadc_channel_init(0, &channel_0_config);
        APP_ERROR_CHECK(err_code);
        err_code = nrf_drv_saadc_channel_init(1, &channel_1_config);
        APP_ERROR_CHECK(err_code);
        err_code = nrf_drv_saadc_channel_init(2, &channel_2_config);
        APP_ERROR_CHECK(err_code);
    
         err_code = nrf_drv_saadc_channel_init(3, &channel_3_config);
        APP_ERROR_CHECK(err_code);
    
         err_code = nrf_drv_saadc_channel_init(4, &channel_4_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);
    
    }
    
    
    
    /**@brief Application main function.
     */
    int main(void)
    {
        bool erase_bonds;
    
        // Initialize.
        uart_init();
        log_init();
        timers_init();
        buttons_leds_init(&erase_bonds);
        power_management_init();
        ble_stack_init();
        gap_params_init();
        gatt_init();
        services_init();
        advertising_init();
        conn_params_init();
        saadc_init();
        advertising_start();
    
    
        
          uint16_t bytes_to_send = 10;
    
        for (;;)
        {     
        
            
            nrf_drv_saadc_sample();
            nrf_delay_ms(2000);  
            ble_nus_data_send(&m_nus, value, &bytes_to_send , m_conn_handle);
    
             idle_state_handle();
        }
    }
    
    
    /**
     * @}
     */
    

Children
  • Can you describe what you are seeing?

    I see that you initialize 5 ADC channels, and your buffer size is 5, but in the callback event, you try to fetch 10 values (from 0 to 9). Do you get random numbers on the last 5 samples? How about the first 5? Do you actually read 5 pins, or only 2?

    BR,

    Edvin

  • Hi Edvin, I am fetching only 5 values in the call back event . T, T1, T2, P1, P2 . Then I just split the 16bit values into two 8 bit values . That's why : value [0-9]. 

    I can't understand what exactly is happening. Like yesterday I hooked up a sensor on AIN4 pin which was my channel 0. So i should have gotten the value in T but instead I received value in P2 which is my channel 4 and pin AIN0. 

    Can you please review the code, only the saadc part and tell what am i doing wrong?

    Thanks,

    Arshdeep 

    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;
            static int adc_value[SAADC_SAMPLES_IN_BUFFER];
            uint16_t T,T1, T2, P1, P2;
           
            uint8_t nus_to_send_array[2];
           
    
            err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAADC_SAMPLES_IN_BUFFER);
            APP_ERROR_CHECK(err_code);
    
            int i;
            NRF_LOG_INFO("ADC event number: %d", (int)m_adc_evt_counter);
    
            for (i = 0; i < SAADC_SAMPLES_IN_BUFFER; i++)
            {
                 // printf("%d\r\n",p_event->data.done.p_buffer[i]);
                   adc_value[i] = p_event->data.done.p_buffer[i];
                
                                          
            }
    
                 
                 R = 10000*((825.5/adc_value[0])-1);
                float logR = log(R);
                 C = C1 + C2*logR + C3*logR*logR*logR;
                T = 1/C;
                T = T - 273.15;
                T = (T*9)/5 + 32;
                T = T/1.009;
    
                 R1 = 10000*((825.5/adc_value[1])-1);
                float logR1 = log(R1);
                 C = C1 + C2*logR1 + C3*logR1*logR1*logR1;
                T1 = 1/C;
                T1 = T1 - 273.15;
                T1 = (T1*9)/5 + 32;
                T1 = T1/1.009;
    
                R2 = 10000*((825.5/adc_value[2])-1);
                float logR2 = log(R2);
                 C = C1 + C2*logR2 + C3*logR2*logR2*logR2;
                T2 = 1/C;
                T2 = T2 - 273.15;
                T2 = (T2*9)/5 + 32;
                T2 = T2/1.009;
    
                P1 = ((adc_value[3] * 3.6)/1024);          
                P1 = P1*(Res2/Res2+Res1);
                P1 = (P1 - 0.5)/4;
                P1 = P1*2;
                P1 = P1*145.038;
    
                P2 = ((adc_value[4] * 3.6)/1024);          
                P2 = P2*(Res2/Res2+Res1);
                P2 = (P2 - 0.5)/4;
                P2 = P2*4;
                P2 = P2*145.038;
    
    
            
            value[0] = (T & 0xFF00) >> 8;
            value[1] = (T & 0x00FF);
            value[2] = (T1 & 0xFF00) >> 8;
            value[3] = (T1 & 0x00FF);
            value[4] = (T2 & 0xFF00) >> 8;
            value[5] = (T2 & 0x00FF);
            value[6] = (P1 & 0xFF00) >> 8;
            value[7] = (P1 & 0x00FF);
            value[8] = (P2 & 0xFF00) >> 8;
            value[9] = (P2 & 0x00FF);
          
    
           //  NRF_LOG_INFO("value1: %d     ",adc_value  );
     //NRF_LOG_INFO("value2: %d     ",  value[0]);
     //NRF_LOG_INFO("value3: %d",  value[1]);
    
       // if((SAADC_SAMPLES_IN_BUFFER*2) <= 20) 
      //      {
        //        bytes_to_send = 4;
        //    }
        //    else 
         //   {
         //       bytes_to_send = 1;
         //   }      
    
       
         //ble_nus_data_send(&m_nus, &value[1], &bytes_to_send , m_conn_handle);
             
             
             //err_code = ble_nus_data_send(&m_nus, &adc_value, &bytes_to_send, m_conn_handle);
    
    
            m_adc_evt_counter++;
    
            
        }
    }
    
    
    
    
    
    void saadc_init(void)
    {
             ret_code_t err_code;
    
    
             //TEMP 1
             nrf_saadc_channel_config_t channel_0_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN4);
    
             //TEMP2
               nrf_saadc_channel_config_t channel_1_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);
    
             //TEMP3
               nrf_saadc_channel_config_t channel_2_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN2);
    
               nrf_saadc_channel_config_t channel_3_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN3);
    
               nrf_saadc_channel_config_t channel_4_config =
             NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN0);
    
        err_code = nrf_drv_saadc_init(NULL, saadc_callback);
        APP_ERROR_CHECK(err_code);
    
        err_code = nrf_drv_saadc_channel_init(0, &channel_0_config);
        APP_ERROR_CHECK(err_code);
        err_code = nrf_drv_saadc_channel_init(1, &channel_1_config);
        APP_ERROR_CHECK(err_code);
        err_code = nrf_drv_saadc_channel_init(2, &channel_2_config);
        APP_ERROR_CHECK(err_code);
    
         err_code = nrf_drv_saadc_channel_init(3, &channel_3_config);
        APP_ERROR_CHECK(err_code);
    
         err_code = nrf_drv_saadc_channel_init(4, &channel_4_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);
    
    }
    
    
    
    /**@brief Application main function.
     */
    int main(void)
    {
        bool erase_bonds;
    
        // Initialize.
        uart_init();
        log_init();
        timers_init();
        buttons_leds_init(&erase_bonds);
        power_management_init();
        ble_stack_init();
        gap_params_init();
        gatt_init();
        services_init();
        advertising_init();
        conn_params_init();
        saadc_init();
    
    
        // Start execution.
        printf("\r\nUART started.\r\n");
        NRF_LOG_INFO("Debug logging for UART over RTT started.");
        advertising_start();
    
         //   nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
         //  spi_config.ss_pin   = SPI_SS_PIN;
        //    spi_config.miso_pin = SPI_MISO_PIN;
        //    spi_config.mosi_pin = SPI_MOSI_PIN;
        //    spi_config.sck_pin  = SPI_SCK_PIN;
        //    spi_config.mode = NRF_DRV_SPI_MODE_0;
        //    spi_config.frequency = NRF_DRV_SPI_FREQ_1M;
        //    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));
    
        
          uint16_t bytes_to_send = 10;
    
        //  nrf_gpio_cfg_output(45);
       //   nrf_gpio_pin_write(45, level_0);
          
    
        // Enter main loop.
        for (;;)
        {     
         //  bytes_to_send = 19;
            
            nrf_drv_saadc_sample();
            nrf_delay_ms(2000);  
         //   DHT_task_callback(34, 10, 11, 12, 13);
         //   nrf_delay_ms(100);   
         //   DHT_task_callback(14, 15, 16, 17, 18);
         //   nrf_delay_ms(100);
            ble_nus_data_send(&m_nus, value, &bytes_to_send , m_conn_handle);
    
            
            
         //   bytes_to_send = 4;
    
         //   DHT_task_callback(2, 0, 1, 2, 3);
         //   nrf_delay_ms(100);
         //   ble_nus_data_send(&m_nus, value, &bytes_to_send , m_conn_handle);
          //  nrf_delay_ms(100);
          
            
    
         
           //  energy_measurement();
            // nrf_delay_ms(1000);
             idle_state_handle();
        }
    }
    
    

  • Hello.

    I am fetching only 5 values in the call back event . T, T1, T2, P1, P2 . Then I just split the 16bit values into two 8 bit values . That's why : value [0-9]. 

    I see. My bad.

    Are you sure that you are using the correct pins? Note that the AIN0-AIN4 are not the same as P0.00-P0.04.

    AIN0: P0.02
    AIN1: P0.03
    AIN2: P0.04
    AIN3: P0.05
    AIN4: P0.28

    Which means that your setup is:

    Ch.0: P0.28
    Ch.1: P0.03
    Ch.2: P0.04
    Ch.3: P0.05
    Ch.4: P0.02

    A couple of mentions regarding your main loop (for(;;)):

    I see that you call nrf_drv_saadc_sample(), and then nrf_delay_ms(2000);

    nrf_drv_saadc_sample() will do one sample. Note that you need SAMPLES_IN_BUFFER samples before you get the saadc_callback() callback. This means that you will only get this callback every 10th second, while you are sending the data every 2nd second. Not a problem in itself, but you should know that you only update the values in value[0-9] every 5th nrf_drv_saadc_sample();

    Another problem may be the nrf_delay_ms(2000). I am surprised if this works well. nrf_delay_ms(n) will keep the CPU running for n ms, without doing anything, blocking the softdevice, and drawing quite a bit of current. Hence, neither the softdevice nor the current consumption are particularly found of this function.

    You can expect to see disconnects from the device you are connected to, and that this project will reset when you are connected, because the softdevice is missing time critical events.

    Instead of using nrf_delay_ms, you should use a timer with a timeout callback. There are two different approaches to this:

    1: You can use the app_timer like it is used in the SDK\examples\ble_peripheral\ble_app_hrs example. Here the timer is used to update the battery service (note that it is only emulating battery values).

    2: You can use the timer together with ppi to trigger the nrf_drv_saadc_sample() calls, like it is done in the SDK\examples\peripheral\saadc example. 

    Then you can use the saadc callback function to set a flag telling the main loop that you should send a notification. Something like this:

    #include "something.h"
    ...
    
    static volatile bool m_send_data = false;
    
    static void saadc_callback(...)
    {
        ...
        m_send_data = true;
    }
    
    static void saadc_init(...)
    {
        ...
    }
    
    static void saadc_start(...)
    {
        ...
    }
    
    int main(void)
    {
        ...
        for(;;)
        {
            if (m_send_data)
            {
                m_send_data = false;
                ble_nus_data_send(...);
            }
            idle_state_handle();
        }
    }

    Best regards,

    Edvin

  • Very well explained Edvin. Thanks.

    So, I don't want the samples after every 10th second. I want them all at 1 second interval . What will be the best way to do so ? As you said, if I use app timer and set an interval of 1 sec. Will it work? And also, what should should be my timeout handler function? saadc_callback or nrf_drv_saadc_sample()  .

    Thanks,

  • The saadc will fetch one sample from every channel you have initialized when you call nrf_drv_saadc_sample(), so if you have 5 channels, and SAMPLES_IN_BUFFER == 5, then you must call nrf_drv_saadc_sample every second if you want to get a measurement from all channels every second. 

    please have a look at the saadc example in SDK\examples\peripheral\saadc

    If you copy the functions:

    saadc_sampling_event_init();
    saadc_sampling_event_enable();

    and only change this line in saadc_sampling_event_init():

    uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer, 400);

    to

    uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer, 1000);

    It will trigger one sampling every second.

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