[STM32] VDDA 보정 기반 LM35 온도 측정 (ADC+AT Command)

 

이번 글에서는 STM32 Nucleo-L073RZ 보드를 이용해 LM35 아날로그 온도 센서의 출력을 ADC로 읽고, VDDA 보정을 적용해 보다 정확한 온도를 계산하는 방법을 정리한다. 단순히 ADC 값만 읽는 것이 아니라, SYS_GetBatteryLevel()로 현재 보드의 VDDA(전원 전압)를 실시간으로 측정한 뒤, 이를 이용해 LM35 센서의 출력 전압을 보정하고 섭씨 온도로 변환하는 과정을 코드와 함께 살펴본다.

 

실습에서는 내부 ADC를 ADC 채널 0으로 설정하고, ADC_ReadChannels()로 읽어온 값을 바탕으로 아래와 같은 계산식을 사용해 온도를 구한다. 

temp = ((measuredLevel * Vdda) / 40950);

 

이때 40950라는 상수는 12비트 ADC 해상도(0~4095)와 LM35의 출력 특성(10mV/°C)를 함께 고려한 값으로, ADC 코드값 → 전압 → 온도(℃)로 바꾸기 위한 스케일링 역할을 한다.

 

또한 단순히 보드에서만 값을 확인하는 것이 아니라, UART를 이용한 시리얼 통신과 hw_vcom.h, command.h를 활용해 AT Command 형태로 온도 정보와 보드 상태를 조회할 수 있도록 구성했다. HW_VCOM_Init()로 USART2를 가상 COM 포트로 초기화하고, CMD_Init(), CMD_Process()를 통해 PC 터미널에서 보내는 문자열 명령을 파싱하는 구조를 사용한다.

 

아래 코드들은 이전에 실습했던 진동 센서 관련 코드가 함께 포함되어 있어 전체 코드가 다소 길다. 이번 글에서는 그중에서도 VDDA 보정을 적용한 LM35 온도 측정과 UART 기반 출력 구조에 초점을 맞춰 정리한다.

 

참고하면 좋을 영상:

https://www.youtube.com/watch?v=0rkR4OrVvQA

 

포스팅 맨 아래 프로젝트 폴더 첨부

 

---

 

Setting

아래와 같이 LM35를 연결하였다.

 

STM32 보드와 LM35를 연결한 다음 작업관리자에서 어디 포트에 연결되었는지 확인한다.

그 후 PuTTY에서 serial을 선택한 후 내 port 번호로 수정해준다.

 

MXCube에서는 ADC를 선택한 후 IN0에 체크해준다.

 

파일 구조는 다음과 같다.

 

---

 

코드 (main.c/.h at.c/.h command.c)

main.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2026 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "adc_if.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

// BSP
#include "stm32l0xx_nucleo.h"

// UART (string)
#include <string.h>
#include <hw_vcom.h>  // custom header  -> set Printf() to UART
#include <command.h>  // custom header  -> parsing command (AT command)

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

#define BUF_SIZE 128

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
ADC_HandleTypeDef hadc;

UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */

// UART
static uint8_t initBuf[BUF_SIZE] = "HELLO. Start NUCLEO-L073RZ\r\n";

uint8_t uart_rcvBuf;  // uart receive buffer
uint8_t enter_buf[2] = "\r\n"; // ENTER = 0x0D 0x0A  (crlf) (\r\n)
volatile uint8_t bUART_RX = 0;

// Vib
volatile uint16_t VibCnt = 0;
volatile uint8_t VibReset = 0;

static uint8_t VibOnBuf[BUF_SIZE] = "Vib is occured!\r\n";
static uint8_t VibOffBuf[BUF_SIZE] = "Vib is not occured!\r\n";

uint32_t lm35_raw = 0;
float    lm35_v_mV = 0.0f;
float    lm35_temp_c = 0.0f;

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_ADC_Init(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
float HW_Get_LM35_Temp(void){
   uint32_t Vdda = SYS_GetBatteryLevel();
   uint16_t measuredLevel = ADC_ReadChannels(ADC_CHANNEL_0);
   float temp = 0;
   
   temp = ((measuredLevel * Vdda) / 40950);
   
   Printf("Celsius = %0.2f, Vdda = %d, measuredA0 = %d\r\n", temp, Vdda, measuredLevel);
   
   return temp;
}
// interrupt mode (HAL_UART_RECEIVE_IT()) -> UART_RX interrupt
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) {
   // if not using hw_vcom
   // bUART_RX = 1;
   
   // if using hw_vcom
   if (huart -> Instance == huart2.Instance) {
      HW_VCOM_RxCpltCallback(huart);
      bUART_RX = 1;
   }
}

// interrupt mode -> override 'weak void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)'
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) {
   // VIB interrupt
   if (GPIO_Pin == GPIO_PIN_5) {
      if (VibCnt < 300U) VibCnt++;
   }
   
   // USER BUTTON
   if (GPIO_Pin == GPIO_PIN_13) {
      VibReset = 1;
   }
}

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{

  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART2_UART_Init();
  MX_ADC_Init();
  /* USER CODE BEGIN 2 */
   
   // using UART -----------------
   
   // // if not using hw_vcom
   // HAL_UART_Transmit(&huart2, initBuf, strlen((const char*)initBuf), 100);
   // HAL_UART_Receive_IT(&huart2, &uart_rcvBuf, 1);
   
   // if using hw_vcom
   Printf((const char*)initBuf);
   
   // if using command.c
   CMD_Init();
   
   // using BSP -------------------
   LEDx_GPIO_CLK_ENABLE(LEDn);
   
   BSP_LED_Init(LED1); // PA8
   BSP_LED_Init(LED2); // PA5
   // BSP_LED_Init(LED3); // PB5
   
   BSP_PB_Init(BUTTON_USER, BUTTON_MODE_EXTI);  // USER BUTTON (interrupt mode)

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
      // UART (interrupt RX) --------------
      #if 0
      if (bUART_RX) {
         bUART_RX = 0;
         
         if (uart_rcvBuf == '\r') {  // ENTER = 0x0D 0x0A  (crlf) (\r\n)
            HAL_UART_Transmit(&huart2, enter_buf, 2, 100);
         }
         else {
            HAL_UART_Transmit(&huart2, &uart_rcvBuf, 1, 100);
         }
         
         HAL_UART_Receive_IT(&huart2, &uart_rcvBuf, 1);
      }
      #endif
      
      // BSP LED ---------------------------
      if (VibReset) {
         VibCnt = 0;
         VibReset = 0;
         BSP_LED_Off(LED1);
         BSP_LED_Off(LED2);
         
         // // if not using hw_vcom
         // HAL_UART_Transmit(&huart2, VibBuf, strlen((const char*)VibOffBuf), 100);
         
         // if using hw_vcom
         Printf((const char*)VibOffBuf);
      }
      
      if (VibCnt >= 300) {
         BSP_LED_Toggle(LED1);
         BSP_LED_Toggle(LED2);
         
         // // if not using hw_vcom
         // HAL_UART_Transmit(&huart2, VibBuf, strlen((const char*)VibOnBuf), 100);
         
         // if using hw_vcom
         Printf((const char*)VibOnBuf);
         
         HAL_Delay(1000);
      }
      
      // if (bUART_RX) {  // UART : when input any charater
      //    Printf("VibCnt = %d\r\n", VibCnt);
      //    bUART_RX = 0;
      // }
      
      // AT Command (use command.c)
      CMD_Process();

      
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};

  /** Configure the main internal regulator output voltage
  */
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
  RCC_OscInitStruct.MSIState = RCC_MSI_ON;
  RCC_OscInitStruct.MSICalibrationValue = 0;
  RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_5;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
  {
    Error_Handler();
  }
  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART2;
  PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;
  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief ADC Initialization Function
  * @param None
  * @retval None
  */
static void MX_ADC_Init(void)
{

  /* USER CODE BEGIN ADC_Init 0 */

  /* USER CODE END ADC_Init 0 */

  ADC_ChannelConfTypeDef sConfig = {0};

  /* USER CODE BEGIN ADC_Init 1 */

  /* USER CODE END ADC_Init 1 */

  /** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
  */
  hadc.Instance = ADC1;
  hadc.Init.OversamplingMode = DISABLE;
  hadc.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV1;
  hadc.Init.Resolution = ADC_RESOLUTION_12B;
  hadc.Init.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
  hadc.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;
  hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc.Init.ContinuousConvMode = DISABLE;
  hadc.Init.DiscontinuousConvMode = DISABLE;
  hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc.Init.DMAContinuousRequests = DISABLE;
  hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc.Init.Overrun = ADC_OVR_DATA_PRESERVED;
  hadc.Init.LowPowerAutoWait = DISABLE;
  hadc.Init.LowPowerFrequencyMode = ENABLE;
  hadc.Init.LowPowerAutoPowerOff = DISABLE;
  if (HAL_ADC_Init(&hadc) != HAL_OK)
  {
    Error_Handler();
  }

  /** Configure for the selected ADC regular channel to be converted.
  */
  sConfig.Channel = ADC_CHANNEL_0;
  sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN ADC_Init 2 */
	SYS_InitMeasurement(&hadc);

  /* USER CODE END ADC_Init 2 */

}

/**
  * @brief USART2 Initialization Function
  * @param None
  * @retval None
  */
static void MX_USART2_UART_Init(void)
{

  /* USER CODE BEGIN USART2_Init 0 */

  /* USER CODE END USART2_Init 0 */

  /* USER CODE BEGIN USART2_Init 1 */
   
   // using hw_vcom
   HW_VCOM_Init(&huart2);
   
   // if not using hw_vcom -> enable (delete #if 0 & #endif)
   #if 0

  /* USER CODE END USART2_Init 1 */
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 9600;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  huart2.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART2_Init 2 */
   #endif

  /* USER CODE END USART2_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  /* USER CODE BEGIN MX_GPIO_Init_1 */

  /* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin : PC13 */
  GPIO_InitStruct.Pin = GPIO_PIN_13;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : PB5 */
  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /* EXTI interrupt init*/
  HAL_NVIC_SetPriority(EXTI4_15_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(EXTI4_15_IRQn);

  /* USER CODE BEGIN MX_GPIO_Init_2 */

  /* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

 

main.h

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.h
  * @brief          : Header for main.c file.
  *                   This file contains the common defines of the application.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2026 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */

/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __MAIN_H
#define __MAIN_H

#ifdef __cplusplus
extern "C" {
#endif

/* Includes ------------------------------------------------------------------*/
#include "stm32l0xx_hal.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Exported types ------------------------------------------------------------*/
/* USER CODE BEGIN ET */

/* USER CODE END ET */

/* Exported constants --------------------------------------------------------*/
/* USER CODE BEGIN EC */

/* USER CODE END EC */

/* Exported macro ------------------------------------------------------------*/
/* USER CODE BEGIN EM */

/* USER CODE END EM */

/* Exported functions prototypes ---------------------------------------------*/
void Error_Handler(void);

/* USER CODE BEGIN EFP */
float HW_Get_LM35_Temp(void);
/* USER CODE END EFP */

/* Private defines -----------------------------------------------------------*/
#define B1_Pin GPIO_PIN_13
#define B1_GPIO_Port GPIOC
#define B1_EXTI_IRQn EXTI4_15_IRQn
#define MCO_Pin GPIO_PIN_0
#define MCO_GPIO_Port GPIOH
#define USART_TX_Pin GPIO_PIN_2
#define USART_TX_GPIO_Port GPIOA
#define USART_RX_Pin GPIO_PIN_3
#define USART_RX_GPIO_Port GPIOA
#define LD2_Pin GPIO_PIN_5
#define LD2_GPIO_Port GPIOA
#define TMS_Pin GPIO_PIN_13
#define TMS_GPIO_Port GPIOA
#define TCK_Pin GPIO_PIN_14
#define TCK_GPIO_Port GPIOA

/* USER CODE BEGIN Private defines */

/* USER CODE END Private defines */

#ifdef __cplusplus
}
#endif

#endif /* __MAIN_H */

 

at.c

/*******************************************************************************
 * @file    at.c
 * @author  MCD Application Team
 * @version V1.1.2
 * @date    08-September-2017
 * @brief   at command API
 ******************************************************************************
 * @attention
 *
 * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics International N.V.
 * All rights reserved.</center></h2>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted, provided that the following conditions are met:
 *
 * 1. Redistribution of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form 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 STMicroelectronics nor the names of other
 *    contributors to this software may be used to endorse or promote products
 *    derived from this software without specific written permission.
 * 4. This software, including modifications and/or derivative works of this
 *    software, must execute solely and exclusively on microcontroller or
 *    microprocessor devices manufactured by or for STMicroelectronics.
 * 5. Redistribution and use of this software other than as permitted under
 *    this license is void and will automatically terminate your rights under
 *    this license.
 *
 * THIS SOFTWARE IS PROVIDED BY STMICROELECTRONICS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY
 * RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT
 * SHALL STMICROELECTRONICS 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.
 *
 ******************************************************************************
 */

/* Includes ------------------------------------------------------------------*/
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include "at.h"
#include "hw_vcom.h"

/* External variables --------------------------------------------------------*/
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/**
 * @brief Max size of the data that can be received
 */
#define MAX_RECEIVED_DATA 255

/* Private macro -------------------------------------------------------------*/
/**
 * @brief Macro to return when an error occurs
 */
#define CHECK_STATUS(status) do {                    \
    ATEerror_t at_status = translate_status(status); \
    if (at_status != AT_OK) { return at_status; }    \
  } while (0)

/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/

/* Exported functions ------------------------------------------------------- */
ATEerror_t at_return_ok(const char *param)
{
  return AT_OK;
}

ATEerror_t at_return_error(const char *param)
{
  return AT_ERROR;
}

ATEerror_t at_reset(const char *param)
{
  NVIC_SystemReset();
  return AT_OK;
}

ATEerror_t at_read_LM35(const char *param)
{
	float celsius = HW_Get_LM35_Temp();
	Printf("Celsius = %0.2f\r\n", celsius);
	return AT_OK;
}

 

at.h

/*******************************************************************************
 * @file    at.h
 * @author  MCD Application Team
 * @version V1.1.2
 * @date    08-September-2017
 * @brief   Header for driver at.c module
 ******************************************************************************
 * @attention
 *
 * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics International N.V.
 * All rights reserved.</center></h2>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted, provided that the following conditions are met:
 *
 * 1. Redistribution of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form 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 STMicroelectronics nor the names of other
 *    contributors to this software may be used to endorse or promote products
 *    derived from this software without specific written permission.
 * 4. This software, including modifications and/or derivative works of this
 *    software, must execute solely and exclusively on microcontroller or
 *    microprocessor devices manufactured by or for STMicroelectronics.
 * 5. Redistribution and use of this software other than as permitted under
 *    this license is void and will automatically terminate your rights under
 *    this license.
 *
 * THIS SOFTWARE IS PROVIDED BY STMICROELECTRONICS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY
 * RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT
 * SHALL STMICROELECTRONICS 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.
 *
 ******************************************************************************
 */

/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __AT_H__
#define __AT_H__

#ifdef __cplusplus
extern "C" {
#endif

/* Includes ------------------------------------------------------------------*/
#include <stdint.h>
#include <string.h>
#include "main.h"
	
/* Exported types ------------------------------------------------------------*/
/*
 * AT Command Id errors. Note that they are in sync with ATError_description static array
 * in command.c
 */
typedef enum eATEerror
{
  AT_OK = 0,
  AT_ERROR,
  AT_PARAM_ERROR,
  AT_BUSY_ERROR,
  AT_TEST_PARAM_OVERFLOW,
  AT_RX_ERROR,
  AT_MAX,
} ATEerror_t;

/* Exported constants --------------------------------------------------------*/
/* External variables --------------------------------------------------------*/
/* Exported macros -----------------------------------------------------------*/
/* AT Command strings. Commands start with AT */
#define AT_RESET      "+RESET"
#define AT_LM35       "+LM35"

/* Exported functions ------------------------------------------------------- */
/**
 * @brief  Return AT_OK in all cases
 * @param  Param string of the AT command - unused
 * @retval AT_OK
 */
ATEerror_t at_return_ok(const char *param);

/**
 * @brief  Return AT_ERROR in all cases
 * @param  Param string of the AT command - unused
 * @retval AT_ERROR
 */
ATEerror_t at_return_error(const char *param);

/**
 * @brief  Trig a reset of the MCU
 * @param  Param string of the AT command - unused
 * @retval AT_OK
 */
ATEerror_t at_reset(const char *param);
#ifdef __cplusplus
}
#endif

#endif /* __AT_H__ */

ATEerror_t at_read_LM35(const char *param);

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

 

command.c

/*******************************************************************************
 * @file    command.c
 * @author  MCD Application Team
 * @version V1.1.2
 * @date    08-September-2017
 * @brief   main command driver dedicated to command AT
 ******************************************************************************
 * @attention
 *
 * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics International N.V.
 * All rights reserved.</center></h2>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted, provided that the following conditions are met:
 *
 * 1. Redistribution of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form 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 STMicroelectronics nor the names of other
 *    contributors to this software may be used to endorse or promote products
 *    derived from this software without specific written permission.
 * 4. This software, including modifications and/or derivative works of this
 *    software, must execute solely and exclusively on microcontroller or
 *    microprocessor devices manufactured by or for STMicroelectronics.
 * 5. Redistribution and use of this software other than as permitted under
 *    this license is void and will automatically terminate your rights under
 *    this license.
 *
 * THIS SOFTWARE IS PROVIDED BY STMICROELECTRONICS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY
 * RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT
 * SHALL STMICROELECTRONICS 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.
 *
 ******************************************************************************
 */

/* Includes ------------------------------------------------------------------*/
#include <stdlib.h>
#include "at.h"
#include "command.h"
#include "hw_vcom.h"

/* comment the following to have help message */
/* #define NO_HELP */

/* Private typedef -----------------------------------------------------------*/
/**
 * @brief  Structure defining an AT Command
 */
struct ATCommand_s {
  const char *string;                       /*< command string, after the "AT" */
  const int size_string;                    /*< size of the command string, not including the final \0 */
  ATEerror_t (*get)(const char *param);     /*< =? after the string to get the current value*/
  ATEerror_t (*set)(const char *param);     /*< = (but not =?\0) after the string to set a value */
  ATEerror_t (*run)(const char *param);     /*< \0 after the string - run the command */
#if !defined(NO_HELP)
  const char *help_string;                  /*< to be printed when ? after the string */
#endif
};

/* Private define ------------------------------------------------------------*/
#define CMD_SIZE 128

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
static const char *const ATError_description[] =
{
  "\r\nOK\r\n",                     /* AT_OK */
  "\r\nAT_ERROR\r\n",               /* AT_ERROR */
  "\r\nAT_PARAM_ERROR\r\n",         /* AT_PARAM_ERROR */
  "\r\nAT_BUSY_ERROR\r\n",          /* AT_BUSY_ERROR */
  "\r\nAT_TEST_PARAM_OVERFLOW\r\n", /* AT_TEST_PARAM_OVERFLOW */
  "\r\nAT_NO_NETWORK_JOINED\r\n",   /* AT_NO_NET_JOINED */
  "\r\nAT_RX_ERROR\r\n",            /* AT_RX_ERROR */
  "\r\nerror unknown\r\n",          /* AT_MAX */
};

/**
 * @brief  Array of all supported AT Commands
 */
static const struct ATCommand_s ATCommand[] =
{
  {
    .string = AT_RESET,
    .size_string = sizeof(AT_RESET) - 1,
#ifndef NO_HELP
    .help_string = "AT"AT_RESET ": Trig a reset of the MCU\r\n",
#endif
    .get = at_return_error,
    .set = at_return_error,
    .run = at_reset,
  },
	{
		.string = AT_LM35,
    .size_string = sizeof(AT_LM35) - 1,
#ifndef NO_HELP
    .help_string = "AT"AT_LM35 ": Get LM35 Celsius value\r\n",
#endif
    .get = at_read_LM35,
    .set = at_return_error,
    .run = at_read_LM35,
	},
};


/* Private function prototypes -----------------------------------------------*/

/**
 * @brief  Print a string corresponding to an ATEerror_t
 * @param  The AT error code
 * @retval None
 */
static void com_error(ATEerror_t error_type);


/**
 * @brief  Parse a command and process it
 * @param  The command
 * @retval None
 */
static void parse_cmd(const char *cmd);

/* Exported functions ---------------------------------------------------------*/

void CMD_Init(void)
{

}

void CMD_Process(void)
{
  static char command[CMD_SIZE];
  static unsigned i = 0;

  /* Process all commands */
  while (IsNewCharReceived() == SET)
  {
    command[i] = GetNewChar();

    Printf("%c", command[i]);

    if (command[i] == AT_ERROR_RX_CHAR)
    {
      i = 0;
      com_error(AT_RX_ERROR);
      break;
    }
    else
    if ((command[i] == '\r') || (command[i] == '\n'))
    {
      if (i != 0)
      {
        command[i] = '\0';
        parse_cmd(command);
        i = 0;
      }
    }
    else
    if (i == (CMD_SIZE - 1))
    {
      i = 0;
      com_error(AT_TEST_PARAM_OVERFLOW);
    }
    else
    {
      i++;
    }
  }
}

/* Private functions ---------------------------------------------------------*/
static void com_error(ATEerror_t error_type)
{
  if (error_type > AT_MAX)
  {
    error_type = AT_MAX;
  }
  Printf(ATError_description[error_type]);
}

static void parse_cmd(const char *cmd)
{
  ATEerror_t status = AT_OK;
  const struct ATCommand_s *Current_ATCommand;
  int i;

  if ((cmd[0] != 'A') || (cmd[1] != 'T'))
  {
    status = AT_ERROR;
  }
  else
  if (cmd[2] == '\0')
  {
    /* status = AT_OK; */
  }
  else
  if (cmd[2] == '?')
  {
#ifdef NO_HELP
#else
    Printf("AT+<CMD>?        : Help on <CMD>\r\n"
              "AT+<CMD>         : Run <CMD>\r\n"
              "AT+<CMD>=<value> : Set the value\r\n"
              "AT+<CMD>=?       : Get the value\r\n");
    for (i = 0; i < (sizeof(ATCommand) / sizeof(struct ATCommand_s)); i++)
    {
      Printf(ATCommand[i].help_string);
    }
#endif
  }
  else
  {
    /* point to the start of the command, excluding AT */
    status = AT_ERROR;
    cmd += 2;
    for (i = 0; i < (sizeof(ATCommand) / sizeof(struct ATCommand_s)); i++)
    {
      if (strncmp(cmd, ATCommand[i].string, ATCommand[i].size_string) == 0)
      {
        Current_ATCommand = &(ATCommand[i]);
        /* point to the string after the command to parse it */
        cmd += Current_ATCommand->size_string;

        /* parse after the command */
        switch (cmd[0])
        {
          case '\0':    /* nothing after the command */
            Printf("\r\n");
            status = Current_ATCommand->run(cmd);
            break;
          case '=':
            Printf("\r\n");
            if ((cmd[1] == '?') && (cmd[2] == '\0'))
            {
              status = Current_ATCommand->get(cmd + 1);
            }
            else
            {
              status = Current_ATCommand->set(cmd + 1);
            }
            break;
          case '?':
            Printf("\r\n");
#ifndef NO_HELP
            Printf(Current_ATCommand->help_string);
#endif
            status = AT_OK;
            break;
          default:
            /* not recognized */
            break;
        }

        /* we end the loop as the command was found */
        break;
      }
    }
  }

  com_error(status);
}

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

 

---

 

결과

아래와 같이 PuTTY에서 AT+LM35를 입력해주면, 온도 값이 출력되는 것을 확인할 수 있다.

 

---

 

프로젝트 폴더

따라하기엔 어렵고, 그래도 궁금하신 분들은 아래 프로젝트 열어서 그대로 동작 시키시면 됩니다!

대신 보드 및 센서와 PuTTY 창은 따로 open 해주셔야 합니다..

L033.zip

18.01MB