current consumption for ble nrf52840

[NANDANI]

I’m writing BLE UART code.
When BLE is not connected, current consumption is ~30 µA.
But when BLE is connected, consumption increases by ~1 mA.
I want to reduce the current during an active BLE connection—ideally back toward the disconnected level.
Is that theoretically possible? What suggestions do you have?

#include <stdio.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_saadc.h"
#include "app_error.h"
//#include "nrf_delay.h"
#include "nrf_drv_ppi.h"
#include "nrf_drv_timer.h"
#include "nrf_gpio.h"
#include "nrfx_rtc.h"
#include "nrf_drv_clock.h"


#include "nrf_drv_rtc.h"
#include "nrf_soc.h"
#include "nrf_nvic.h"
#include "app_error.h"
#include "app_util_platform.h"
#include "nrf_pwr_mgmt.h"

#include "app_error.h"
#include "nrf_drv_clock.h"
#include "nrf_nvmc.h"


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

#include "boards.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
//#include "nrf_log_default_backends.h"


//#define ADC_UPDATE_INTERVAL_MIN 1 // ADC update interval in minutes
//#define TICK_INTERVAL_MS 125
//#define TOTAL_TICKS ((ADC_UPDATE_INTERVAL_MIN * 60000) / TICK_INTERVAL_MS) 
//const nrfx_rtc_t rtc = NRFX_RTC_INSTANCE(2);
//volatile uint32_t tick_count = 0;  // Tick counter
//nrf_saadc_value_t adc_val;
//nrf_saadc_value_t adc_save[360];  // Array to store ADC samples
//uint16_t i = 0; 


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

#define DEVICE_NAME                     "MAyur_Nordic"                               /**< 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                1600//64                                          /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */

#define APP_ADV_DURATION                6000//18000                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(300, UNIT_1_25_MS) //100  //200            /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(400, UNIT_1_25_MS)  //200  //400           /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */
#define SLAVE_LATENCY                   2//4//0                                           /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */
#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                       /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                      /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */

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

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


BLE_NUS_DEF(m_nus, 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}
};

void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name);
static void timers_init(void);
static void gap_params_init(void);
static void nrf_qwr_error_handler(uint32_t nrf_error);
static void nus_data_handler(ble_nus_evt_t * p_evt);
static void services_init(void);
static void on_conn_params_evt(ble_conn_params_evt_t * p_evt);

static void conn_params_error_handler(uint32_t nrf_error);
static void conn_params_init(void);
static void on_adv_evt(ble_adv_evt_t ble_adv_evt);
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context);
static void ble_stack_init(void);
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt);
void gatt_init(void);
void uart_event_handle(app_uart_evt_t * p_event);
static void uart_init(void);
static void advertising_init(void);
static void log_init(void);
static void advertising_start(void);

void idle_state_handle()
{
          __WFE();   // Wait for event (low-power)
          __SEV();   // Set event (in case event missed)
          __WFE();   // Wait again to enter sleep
}

void uart_disable(void)
{
    app_uart_close();  // Closes UART FIFO and disables interrupts
}

int main(void)
{   

  // NRF_POWER->DCDCEN = 1;  // Enable DC/DC converter
  
    timers_init();
    ble_stack_init();   // ble work that time nvmc is not work. for data save. 
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();
    advertising_start();
    printf("application start");
    for (;;)
    {
     idle_state_handle();
    }
}



void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name)
{
    app_error_handler(DEAD_BEEF, line_num, p_file_name);
}

static void timers_init(void)
{
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
}

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);
}

static void nrf_qwr_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}

//static void nus_data_handler(ble_nus_evt_t * p_evt)
//{
//	// A variable to hold the error code FOR THE 

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

//        uint8_t data[200]; 
        
//       // 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);
//        }
//    }

//}


static void nus_data_handler(ble_nus_evt_t * p_evt)
{
    if (p_evt->type == BLE_NUS_EVT_RX_DATA)
    {
        uint8_t data[200];
        uint8_t data1[20];

        // Copy received data and null-terminate
        memcpy(data, p_evt->params.rx_data.p_data, p_evt->params.rx_data.length);
        data[p_evt->params.rx_data.length] = '\0';

        // ✅ Print received data over BLE
        printf("Received over BLE: %s\n", data);

        sprintf((char *)data1, "ADC: %s", data);

        uint16_t length = strlen((char *)data1);
        uint32_t err_code = ble_nus_data_send(&m_nus, data, &length, m_conn_handle);

         if (err_code == NRF_SUCCESS)
        {
            printf("Sent over BLE: %s\n", data1); // Print confirmation on SES Terminal
        }
        else
        {
            printf("BLE Send Error: %d\n", err_code);
        }

        // ✅ Optional: Echo back to UART (if needed)
        for (uint32_t i = 0; i < p_evt->params.rx_data.length; i++)
        {
            while (app_uart_put(p_evt->params.rx_data.p_data[i]) == NRF_ERROR_BUSY);
        }

        // Add newline if '\r' was last character
        if (p_evt->params.rx_data.p_data[p_evt->params.rx_data.length - 1] == '\r')
        {
            while (app_uart_put('\n') == NRF_ERROR_BUSY);
        }
    }
}

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);
}

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);
    }
}

static void conn_params_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}

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);
}



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:
        idle_state_handle();
            break;
        case BLE_ADV_EVT_IDLE:
           // sleep_mode_enter();
           //sd_power_system_off();
           advertising_start();  // Restart advertising
            break;
        default:
            break;
    }
}

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")
            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);
            uart_init();
             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;
            uart_disable();
            //sd_power_system_off();  // Power down
           idle_state_handle();
                      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;
    }
}


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);
}

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);
}

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);
}



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;
    }
}



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);


    NRF_P0->PIN_CNF[RX_PIN_NUMBER] |= GPIO_PIN_CNF_PULL_Msk;
}
/**@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 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);
}

[Tubald]

Hello,
Sorry for not knowing the answer to your question, but maybe you can help me answer mine.
How do you measure the current consumption? I am trying to do this on my nrf52840 with a multimeter, but without any success.

I would really appreciate if you could tell me how to do it. 

Thank you

[NANDANI]

power profiler kit using measure current consumption.