[NRF52] 내부 온도 값 읽기

IDE: SEGGER Embedded Studio for ARM V6.30

SDK: nRF5_SDK_17.1.0

 

 

nrf52832는 내부 온도센서를 가지고 있습니다.

nRF52832 Product Specification v1.4 에 명시된 온도센서

 

온도센서 정보

 

 

온도값의 범위는 디바이스의 동작 온도보다 크거나 같습니다.

온도값의 분해능은 0.25도로 레지스터 값이 4일 때 1도를 나타냅니다. 

 

이를 사용하기 위해 SDK에서는 예제 프로그램도 제공되고 있습니다.

>> nRF5_SDK_17.1.0_ddde560\examples\peripheral\temperature

 

/**
 * Copyright (c) 2014 - 2021, 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 temperature_example_main main.c
* @{
* @ingroup temperature_example
* @brief Temperature Example Application main file.
* @details
* This file contains the source code for a sample application using the temperature sensor.
* This contains workaround for PAN_028 rev2.0A anomalies 28, 29,30 and 31. PAN 43 is not covered.
*  - PAN_028 rev2.0A anomaly 28 - TEMP: Negative measured values are not represented correctly
*  - PAN_028 rev2.0A anomaly 29 - TEMP: Stop task clears the TEMP register.
*  - PAN_028 rev2.0A anomaly 30 - TEMP: Temp module analog front end does not power down when DATARDY event occurs.
*  - PAN_028 rev2.0A anomaly 31 - TEMP: Temperature offset value has to be manually loaded to the TEMP module
*  - PAN_028 rev2.0A anomaly 43 - TEMP: Using PPI between DATARDY event and START task is not functional.
*
*/

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "nrf.h"
#include "nrf_delay.h"
#include "nrf_temp.h"
#include "app_error.h"
#include "bsp.h"

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
/** @brief Function for main application entry.
 */
int main(void)
{
    // This function contains workaround for PAN_028 rev2.0A anomalies 28, 29,30 and 31.
    int32_t volatile temp;

    nrf_temp_init();

    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();
    NRF_LOG_INFO("Temperature example started.");

    while (true)
    {
        NRF_TEMP->TASKS_START = 1; /** Start the temperature measurement. */

        /* Busy wait while temperature measurement is not finished, you can skip waiting if you enable interrupt for DATARDY event and read the result in the interrupt. */
        /*lint -e{845} // A zero has been given as right argument to operator '|'" */
        while (NRF_TEMP->EVENTS_DATARDY == 0)
        {
            // Do nothing.
        }
        NRF_TEMP->EVENTS_DATARDY = 0;

        /**@note Workaround for PAN_028 rev2.0A anomaly 29 - TEMP: Stop task clears the TEMP register. */
        temp = (nrf_temp_read() / 4);

        /**@note Workaround for PAN_028 rev2.0A anomaly 30 - TEMP: Temp module analog front end does not power down when DATARDY event occurs. */
        NRF_TEMP->TASKS_STOP = 1; /** Stop the temperature measurement. */

        NRF_LOG_INFO("Actual temperature: %d", (int)temp);
        nrf_delay_ms(500);

        NRF_LOG_FLUSH();
    }
}


/** @} */

 

위는 500ms마다 온도 값을 읽는 동작을 하는 코드입니다.

 

위 코드를 참조하여 다른 ble_app_uart 와 같은 예제 프로그램에서 적용하니까 다음과 같은 에러가 나타나면서 Hard Fault가 발생하는 것을 보게 됩니다.

 

SOFTDEVICE: INVALID MEMORY ACCESS

 

SOFTDEVICE를 사용하면 메모리에 직접 접근이 안되서 나타나는 현상으로

다음과 같은 코드로 내부 온도 값을 읽을 수 있습니다.

 

int32_t temp;
sd_temp_get(&temp);
temp = (int)temp / 4;

 

 

참조

nRF52832 Product Specification (nordicsemi.com)

nrf_temp_read() or sd_temp_get(&t) fault with S132 - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)