【NUCLEO-F446RE试用体验】+9.HAL库之DHT11的读取

#include "dht11.h"

#include "stm32f4xx_hal.h"

//¸´Î»DHT11

void Dht11_Set_Output(void)

{

  GPIO_InitTypeDef GPIO_InitStruct;



  /*Configure GPIO pins : PA1 */

  GPIO_InitStruct.Pin = GPIO_PIN_1;

  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;

  GPIO_InitStruct.Pull = GPIO_PULLUP;

  GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;

  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);



}



void Dht11_Set_Input(void)

{



  GPIO_InitTypeDef GPIO_InitStruct;



  /*Configure GPIO pins : PA1 */

  GPIO_InitStruct.Pin = GPIO_PIN_1;

  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;

	GPIO_InitStruct.Pull = GPIO_PULLUP;

  GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;

  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);



}



//??DHT11

void DHT11_Rst(void)	   

{                 

	DHT11_IO_OUT(); 	//SET OUTPUT

    DHT11_DQ_OUT=0; 	//??DQ

    HAL_Delay(20*1000);    	//????18ms

    DHT11_DQ_OUT=1; 	//DQ=1 

	HAL_Delay(30);     	//????20~40us

}

//??DHT11???

//??1:????DHT11???

//??0:??

uint8_t DHT11_Check(void) 	   

{   

	uint8_t retry=0;

	DHT11_IO_IN();//SET INPUT	 

    while (DHT11_DQ_IN&&retry<100)//DHT11???40~80us

	{

		retry++;

		HAL_Delay(1);

	};	 

	if(retry>=100)return 1;

	else retry=0;

    while (!DHT11_DQ_IN&&retry<100)//DHT11????????40~80us

	{

		retry++;

		HAL_Delay(1);

	};

	if(retry>=100)return 1;	    

	return 0;

}

//?DHT11?????

//???:1/0

uint8_t DHT11_Read_Bit(void) 			 

{

 	uint8_t retry=0;

	while(DHT11_DQ_IN&&retry<100)//???????

	{

		retry++;

		HAL_Delay(1);

	}

	retry=0;

	while(!DHT11_DQ_IN&&retry<100)//??????

	{

		retry++;

		HAL_Delay(1);

	}

	HAL_Delay(40);//??40us

	if(DHT11_DQ_IN)return 1;

	else return 0;		   

}

//?DHT11??????

//???:?????

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;

}

//?DHT11??????

//temp:???(??:0~50°)

//humi:???(??:20%~90%)

//???:0,??;1,????

uint8_t DHT11_Read_Data(uint8_t *temp,uint8_t *humi)    

{        

 	uint8_t buf;

	uint8_t i;

	DHT11_Rst();

	if(DHT11_Check()==0)

	{

		for(i=0;i<5;i++)//??40???

		{

			buf=DHT11_Read_Byte();

		}

		if((buf+buf+buf+buf)==buf)

		{

			*humi=buf;

			*temp=buf;

		}

	}else return 1;

	return 0;	    

}

//???DHT11?IO? DQ ????DHT11???

//??1:???

//??0:??    	 

uint8_t DHT11_Init(void)

{	 

 	GPIO_InitTypeDef  GPIO_Initure;

 	

 	__HAL_RCC_GPIOB_CLK_ENABLE();           //??GPIOA??

	

    GPIO_Initure.Pin=GPIO_PIN_12; //PB1,0

    GPIO_Initure.Mode=GPIO_MODE_OUTPUT_PP;  //????

    GPIO_Initure.Pull=GPIO_PULLUP;          //??

    GPIO_Initure.Speed=GPIO_SPEED_HIGH;     //??

    HAL_GPIO_Init(GPIOB,&GPIO_Initure);

		HAL_GPIO_WritePin(GPIOB,GPIO_PIN_12,GPIO_PIN_SET);						 //PA3 ???

			    

	DHT11_Rst();  //??DHT11

	return DHT11_Check();//??DHT11???

} 

（2）、dht11.h代码如下：

#ifndef __DHT11_H

#define __DHT11_H 

#include "stm32f4xx_hal.h"

#include "sys.h"





#define DHT11_IO_IN()  {GPIOB->MODER&=~(3<<(12*2));GPIOB->MODER|=0<<(12*2);}	//PB12????

#define DHT11_IO_OUT() {GPIOB->MODER&=~(3<<(12*2));GPIOB->MODER|=1<<(12*2);} 



#define	DHT11_DQ_OUT PBout(12) 

#define	DHT11_DQ_IN  PBin(12)  



void Dht11_Set_Output(void);

void Dht11_Set_Input(void);

uint8_t DHT11_Init(void);//³õʼ»¯DHT11

uint8_t DHT11_Read_Data(uint8_t *temp,uint8_t *humi);//¶ÁÈ¡ÎÂʪ¶È

uint8_t DHT11_Read_Byte(void);//¶Á³öÒ»¸ö×Ö½Ú

uint8_t DHT11_Read_Bit(void);//¶Á³öÒ»¸öλ

uint8_t DHT11_Check(void);//¼ì²âÊÇ·ñ´æÔÚDHT11

void DHT11_Rst(void); 

#endif

（3）、main.c代码如下：

int main(void)

{

	uint8_t t,temperature,humidity;

  HAL_Init();

  SystemClock_Config();

  MX_GPIO_Init();

  MX_TIM6_Init();

  MX_USART2_UART_Init();

  MX_NVIC_Init();

	while(DHT11_Init())	//DHT11³õʼ»¯	

	{

		HAL_Delay(100*1000);

		printf("init....\r\n");

	}	

  while (1)

  {

		if(t%10==0)			//ÿ100ms¶ÁÈ¡Ò»´Î

		{									  

			DHT11_Read_Data(&temperature,&humidity);	//¶ÁÈ¡ÎÂʪ¶ÈÖµ	

			printf("temperature:%d  humidity:%d\r\n",temperature,humidity);

		}

		HAL_Delay(10*1000);//ÑÓ³Ù10ms

		if(++t==20)

		{

			t=0;

			HAL_GPIO_TogglePin(GPIOA,GPIO_PIN_5);  

		} 

  }

}

注意，写DHT11驱动的时候需要us级别的延时，这个怎么做的呢？见下图，直接将1000改成1000000即可，即就是1us进一次systick中断。如下图： （4）、采集到的温湿度效果图： 好的本次实验完成，这次实验没有写文档，因为只是个DHT11的驱动，没什么可以写的。。 谢谢大家！！！！