【STM32 IIC通信与温湿度传感器AHT20（I2C_AHT20）】

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最终效果展示

详细讲解视频

AHT20温湿度传感器（I2C_AHT20）

通过I²C读取AHT20温湿度计

板载AHT20传感器规格：

学习板上的AHT20传感器：

• 编译并下载程序到学习板
• 使用配套TYPE-C数据线，将学习板连接到计算机

• 打开波特律动 串口助手 (keysking.com)在线串口调试助手，点击“选择串口”，选择USB Single Serial
• 此时即可收到温湿度信息，如图所示

1、工程配置

• 打开I²C外设：Pinout&Configuration -> Connectivity -> I2C1，将I2C模式选择为I2C

• 打开串口2外设：Pinout&Configuration -> Connectivity -> USART2，将Mode选择为Asynchronous

• 配置工程：在Project Manager -> Code Generator页面中，勾选Generate peripheral initialization as … per peripheral

2、代码

新建一个源文件和头文件

aht20.h

/*
 * aht20.h
 *
 *  Created on: Apr 25, 2024
 *      Author: lenovo
 */

#ifndef INC_AHT20_H_
#define INC_AHT20_H_

#include "i2c.h"
 void AHT20_Init ();

 void AHT20_Read(float *Temperature , float *Humidity);
#endif /* INC_AHT20_H_ */

aht20.c

#include "aht20.h"

#define AHT20_ADDRESS 0x70 // 从机地址
//AHT20 的驱动程序
 void AHT20_Init () //AHT20初始化函数  记住要在"aht20.h"中声明
{
  uint8_t readBuffer;//用于接收状态信息
  HAL_Delay(40);
  HAL_I2C_Master_Receive(&hi2c1, AHT20_ADDRESS, &readBuffer, 1, HAL_MAX_DELAY);//I2C读取函数，读数据函数 readBuffer此时获得了一个字节的状态字。
  if((readBuffer & 0x08) == 0x00) //判断第三位是否为0 发送0xBE命令初始化
  {
	  uint8_t sendBuffer [3] = {0xBE , 0x08 , 0x00};
	  HAL_I2C_Master_Transmit(&hi2c1, AHT20_ADDRESS, sendBuffer, 3, HAL_MAX_DELAY);//I2C发送函数
  }

}

 void AHT20_Read(float *Temperature , float *Humidity) //AHT20读取温度湿度函数  记住要在"aht20.h"中声明
{
	uint8_t sendBuffer [3] = {0xAC , 0x33 , 0x00};
	uint8_t readBuffer [6];
	HAL_I2C_Master_Transmit(&hi2c1, AHT20_ADDRESS, sendBuffer, 3, HAL_MAX_DELAY);
	HAL_Delay(75);
	HAL_I2C_Master_Receive(&hi2c1, AHT20_ADDRESS, readBuffer, 6, HAL_MAX_DELAY);
	if((readBuffer[0] & 0x80) == 0x00)
	{
		uint32_t date = 0;//接收温湿度需要2个半字节 所以要32
		date = ((uint32_t )readBuffer[3] >> 4) + ((uint32_t )readBuffer[2] << 4) + ((uint32_t )readBuffer[1] << 12);//对数据进行移位拼接.
		*Humidity = date * 100.0f / (1 << 20);//(1 << 20) 意为2的20次方. 乘100.0可以表示为百分数

		date = (((uint32_t )readBuffer[3] & 0x0F)<< 16) + ((uint32_t )readBuffer[4] << 8) + (uint32_t )readBuffer[5];//& 0x0F: 将这个无符号整数与十六进制数0x0F进行按位与操作。0x0F的二进制表示为00001111，这个操作会保留readBuffer[3]的低四位，即将高四位清零。
		*Temperature = date * 200.0f / (1 << 20) - 50;
	}
}

main.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 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 "i2c.h"
#include "usart.h"
#include "gpio.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "i2c.h"
#include <stdio.h>
#include "string.h"
/* USER CODE END Includes */

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

/* USER CODE END PTD */

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

/* USER CODE END PD */

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

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* 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_I2C1_Init();
  MX_USART2_UART_Init();
  /* USER CODE BEGIN 2 */
  AHT20_Init ();//初始化AHT20

  float temperature , humidity ;
  char message [50];
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
	  AHT20_Read( &temperature , &humidity); //读取AHT20
	  sprintf(message ,"温度: %.lf ℃ , 湿度: %.lf %%\r\n",temperature , humidity);//拼接
	  HAL_UART_Transmit(&huart2, (uint8_t*)message,strlen(message) , HAL_MAX_DELAY);//串口发�?�函�?
	  HAL_Delay(1000);
    /* 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};

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  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_HSI;
  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();
  }
}

/* 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 */

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