本文介绍了如何在STM32平台上使用DHT11温湿度传感器进行数据采集，通过定时器实现us级计时，并在STM32CubeMX配置中详细展示了GPIO操作和串口通信的设置。

一、实现思路

1、配置DHT11引脚

2、配置串口uart1

3、配置定时器实现us延时

4、配置时钟

二、STM32CubeMX配置

1、配置DHT11引脚

stm32f103zet6精英板的引脚是PG11。

2、配置串口uart1

3、配置定时器实现us延时

4、配置时钟

生成代码。

三、导入DHT11库

DHT11.c（tim.h由cubeMX配置定时器生成）

#include "dht11.h"
#include "tim.h"

#define DHT11_GPIO_PORT 		GPIOG
#define DHT11_GPIO_PIN 			GPIO_PIN_11
#define	DHT11_DQ_IN  		    HAL_GPIO_ReadPin(DHT11_GPIO_PORT, DHT11_GPIO_PIN)

void delay_us(uint16_t nus){       //  DHT11 微秒延时函数
    __HAL_TIM_SetCounter(&htim1,0);
    __HAL_TIM_ENABLE(&htim1);
    while( __HAL_TIM_GetCounter(&htim1)< nus);
    __HAL_TIM_DISABLE(&htim1);
}

static void DHT11_IO_IN(void)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0};

    GPIO_InitStruct.Pin = DHT11_GPIO_PIN;
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    HAL_GPIO_Init(DHT11_GPIO_PORT, &GPIO_InitStruct);
}

static void DHT11_IO_OUT(void)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0};

    GPIO_InitStruct.Pin = DHT11_GPIO_PIN;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(DHT11_GPIO_PORT, &GPIO_InitStruct);
}

//复位DHT11  \\起始
void DHT11_Rst(void)
{
    DHT11_IO_OUT(); 	//SET OUTPUT  转换成输出模式
    HAL_GPIO_WritePin(DHT11_GPIO_PORT, DHT11_GPIO_PIN, GPIO_PIN_RESET); 	//拉低DQ
    HAL_Delay(20);    	//拉低至少18ms
    HAL_GPIO_WritePin(DHT11_GPIO_PORT, DHT11_GPIO_PIN, GPIO_PIN_SET);		//DQ=1
    delay_us(30);     	//主机拉高20~40us
}

//等待DHT11的回应
//返回1:未检测到DHT11的存在
//返回0:存在
uint8_t DHT11_Check(void)
{
    uint8_t retry=0;
    DHT11_IO_IN();//SET INPUT
    while (DHT11_DQ_IN&&retry<100)//DHT11会拉低40~80us
    {
        retry++;
        delay_us(1);
    };
    if(retry>=100)return 1;
    else retry=0;
    while (!DHT11_DQ_IN&&retry<100)//DHT11拉低后会再次拉高40~80us
    {
        retry++;
        delay_us(1);
    };
    if(retry>=100)return 1;
    return 0;
}

//从DHT11读取一个位
//返回值：1/0
uint8_t DHT11_Read_Bit(void)
{
    uint8_t retry=0;
    while(DHT11_DQ_IN&&retry<100)//等待变为低电平
    {
        retry++;
        delay_us(1);
    }//延时100
    retry=0;
    while(!DHT11_DQ_IN&&retry<100)//等待变高电平
    {
        retry++;
        delay_us(1);
    }
    delay_us(40);//等待40us
    if(DHT11_DQ_IN)return 1;
    else return 0;
}

//从DHT11读取一个字节
//返回值：读到的数据
uint8_t DHT11_Read_Byte(void)
{
    uint8_t i,dat;
    dat=0;
    for (i=0; i<8; i++)
    {
        dat<<=1;
        dat|=DHT11_Read_Bit();
    }
    return dat;
}

//从DHT11读取一次数据
//temp:温度值(范围:0~50°)
//humi:湿度值(范围:20%~90%)
//返回值：HAL_OK,正常;1,读取失败
uint8_t DHT11_Read_Data(uint8_t *humiH,uint8_t *humiL,uint8_t *tempH,uint8_t *tempL)
{
    uint8_t buf[5];
    uint8_t i;
    DHT11_Rst();
    if(DHT11_Check()==0)
    {
        for(i=0; i<5; i++) //读取40位数据
        {
            buf[i]=DHT11_Read_Byte();
        }
        if((buf[0]+buf[1]+buf[2]+buf[3])==buf[4])
        {
            *humiH=buf[0];
            *humiL=buf[1];
            *tempH=buf[2];
            *tempL=buf[3];

        }
    } else
        return HAL_ERROR;

    return HAL_OK;
}


//初始化DHT11的IO口 DQ 同时检测DHT11的存在
//返回1:不存在
//返回0:存在
uint8_t FS_DHT11_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0};

    GPIO_InitStruct.Pin = DHT11_GPIO_PIN;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(DHT11_GPIO_PORT, &GPIO_InitStruct);

    HAL_GPIO_WritePin(DHT11_GPIO_PORT, DHT11_GPIO_PIN, GPIO_PIN_SET);	// 输出高
    DHT11_Rst();  //复位DHT11
    return DHT11_Check();//等待DHT11的回应
}

DHT11.h

#ifndef __DHT11_H__
#define __DHT11_H__

#include "main.h"

uint8_t DHT11_Read_Data(uint8_t *humiH,uint8_t *humiL,uint8_t *tempH,uint8_t *tempL);
uint8_t FS_DHT11_Init(void);
uint8_t DHT11_Check(void);

#endif

在mian函数中调用头文件 

#include "dht11.h"

 重定向printf

#include "stdio.h"
#include "string.h"
    __ASM (".global __use_no_semihosting");    
    struct FILE {int handle; };
     FILE __stdout;
    void _sys_exit(int x) { x = x; }
    void _ttywrch(int ch){ ch = ch;}
    int fputc(int ch, FILE *f)    
    {
       uint8_t temp[1] = {ch};
       HAL_UART_Transmit(&huart1, temp, 1, 2);
       return ch;
    }

main.c

/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "stdio.h"
#include "string.h"
#include "dht11.h"
    __ASM (".global __use_no_semihosting");    
    struct FILE {int handle; };
     FILE __stdout;
    void _sys_exit(int x) { x = x; }
    void _ttywrch(int ch){ ch = ch;}
    int fputc(int ch, FILE *f)    
    {
       uint8_t temp[1] = {ch};
       HAL_UART_Transmit(&huart1, temp, 1, 2);
       return ch;
    }
/* 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 */
uint8_t humiH,humiL,tempH,tempL;
/* 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_USART1_UART_Init();
  MX_TIM1_Init();
  /* USER CODE BEGIN 2 */
	FS_DHT11_Init();
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
		DHT11_Read_Data(&humiH,&humiL,&tempH,&tempL);
		printf("humi:%d.%d temp:%d.%d\n",humiH,humiL,tempH,tempL);
		HAL_Delay(1000);
    /* USER CODE END WHILE */

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

最后烧录调试，会有以下现象。

至此DHT11_串口通信完成。