Low Power Mode using app uart example

Question

Hello ,

I on the DK nRF52840, I wanted to manage the sleep mode and measure the current consumed by the microcontroller.

I started with example uart, I cut the PCB track courting solder bridge SB40 and I soldered a 10 Ω resistor .

the current measured with oscilloscope 0.216A (I measure the voltage between the resistance and i divide by 10 ).

, and once the microcontroller goes to sleep, I measure 0.241A, which means that the microphone does not go into sleep mode . can you help me please .

why it doesn't go to sleep ?

Best regards,/**
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/** @file
 * @defgroup uart_example_main main.c
 * @{
 * @ingroup uart_example
 * @brief UART Example Application main file.
 *
 * This file contains the source code for a sample application using UART.
 *
 */

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "app_uart.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "nrf.h"
#include "bsp.h"
#if defined (UART_PRESENT)
#include "nrf_uart.h"
#endif
#if defined (UARTE_PRESENT)
#include "nrf_uarte.h"
#endif

#include "nrf_pwr_mgmt.h"

#define MAX_TEST_DATA_BYTES     (15U)                /**< max number of test bytes to be used for tx and rx. */
#define UART_TX_BUF_SIZE 256                         /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 256                         /**< UART RX buffer size. */
#define UART_HWFC APP_UART_FLOW_CONTROL_DISABLED

uint8_t cr;

void uart_deinit(void)
{
   app_uart_close();

   NRF_UART0->TASKS_STOPTX = 1 ;

   NRF_UART0->TASKS_STOPRX = 1 ;

   NRF_UART0->ENABLE = UART_ENABLE_ENABLE_Disabled << UART_ENABLE_ENABLE_Pos; ;

   *(uint32_t volatile *)0x40002FFC = 0 ;

   *(uint32_t volatile *)0x40002FFC ;

   *(uint32_t volatile *)0x40002FFC = 1 ;

}


void uart_error_handle(app_uart_evt_t * p_event)
{
    if (p_event->evt_type == APP_UART_COMMUNICATION_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_communication);
    }
    else if (p_event->evt_type == APP_UART_FIFO_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_code);
    }
    else if(p_event->evt_type == APP_UART_DATA_READY)
    {

    }
    else if( p_event->evt_type == APP_UART_TX_EMPTY)
    {
        if (cr == 'q' || cr == 'Q')
        {
            printf(" \r\nExit!\r\n");

            /* Disable the UART0 peripheral */
            uart_deinit();

            while (true)
            {
                /* Going to sleep */
                nrf_pwr_mgmt_run(); 
            }
        }
    }
}


/**
 * @brief Function for main application entry.
 */
int main(void)
{
    uint32_t err_code;

    bsp_board_init(BSP_INIT_LEDS);

    const app_uart_comm_params_t comm_params =
      {
          RX_PIN_NUMBER,
          TX_PIN_NUMBER,
          RTS_PIN_NUMBER,
          CTS_PIN_NUMBER,
          UART_HWFC,
          false,
#if defined (UART_PRESENT)
          NRF_UART_BAUDRATE_115200
#else
          NRF_UARTE_BAUDRATE_115200
#endif
      };

    APP_UART_FIFO_INIT(&comm_params,
                         UART_RX_BUF_SIZE,
                         UART_TX_BUF_SIZE,
                         uart_error_handle,
                         APP_IRQ_PRIORITY_LOWEST,
                         err_code);

    APP_ERROR_CHECK(err_code);

    printf("\r\nUART example started.\r\n");

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


/** @} */