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標題: 學習筆記—STM32F103獲取DHT11溫濕度,串口輸出程序 [打印本頁]

作者: qyljzjxl 時間: 2021-12-28 12:49
標題: 學習筆記—STM32F103獲取DHT11溫濕度,串口輸出程序
（一）查閱DHT11數據數據手冊

（二）為了使用printf打印函數需要進行修改。
usart.h增加：int fputc(int ch, FILE *f);
usart.c增加：
int fputc(int ch, FILE *f)
{
USART_SendData(USART1, (uint8_t) ch);
while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET);
return ch;
}
（三）DHT11函數代碼
dht11.h文件:
//
#ifndef __DHT11_H__
#define __DHT11_H__
#include "stm32f10x_gpio.h"
#define DHT11_GPIO_TYPE  GPIOB
#define DHT11_GPIO_PIN GPIO_Pin_8
#define DHT11_RCC       RCC_APB2Periph_GPIOB
#define DHT11_OUT_H GPIO_SetBits(DHT11_GPIO_TYPE, DHT11_GPIO_PIN)
#define DHT11_OUT_L GPIO_ResetBits(DHT11_GPIO_TYPE, DHT11_GPIO_PIN)
#define DHT11_IN GPIO_ReadInputDataBit(DHT11_GPIO_TYPE, DHT11_GPIO_PIN)
void dht11_gpio_input(void);
void dht11_gpio_output(void);
u16 dht11_scan(void);
u16 dht11_read_bit(void);
u16 dht11_read_byte(void);
u16 dht11_read_data(u8 buffer[4]);
#endif
//

dht11.c文件
//
#include "dht11.h"
#include "delay.h"
u8 checksum;
void dht11_gpio_input(void)
{ GPIO_InitTypeDef g;
RCC_APB2PeriphClockCmd(DHT11_RCC, ENABLE);
g.GPIO_Pin = DHT11_GPIO_PIN;
g.GPIO_Speed = GPIO_Speed_50MHz;
g.GPIO_Mode = GPIO_Mode_IN_FLOATING; //
GPIO_Init(DHT11_GPIO_TYPE, &g);
}

void dht11_gpio_output(void)
{ GPIO_InitTypeDef g;
   RCC_APB2PeriphClockCmd(DHT11_RCC, ENABLE);
   g.GPIO_Pin = DHT11_GPIO_PIN;
g.GPIO_Speed = GPIO_Speed_50MHz;
g.GPIO_Mode = GPIO_Mode_Out_PP; //
GPIO_Init(DHT11_GPIO_TYPE, &g);
}

void dht11_reset(void)
{
//
dht11_gpio_output();
DHT11_OUT_L;
delay_us(19000);
DHT11_OUT_H;
delay_us(30);
dht11_gpio_input();
}

u16 dht11_scan(void)
{
return DHT11_IN;
}

u16 dht11_read_bit(void)
{
while (DHT11_IN == RESET);
delay_us(40);
if (DHT11_IN == SET)
{
      while (DHT11_IN == SET);
      return 1;
}
else
{
      return 0;
}
}

u16 dht11_read_byte(void)
{
u16 i;
u16 data = 0;
for (i = 0; i < 8; i++)
{
      data <<= 1;
      data |= dht11_read_bit();
}
return data;
}

u16 dht11_read_data(u8 buffer[5])
{
u16 i = 0;

dht11_reset();
if (dht11_scan() == RESET)
{
      //檢測到DHT11響應
      while (dht11_scan() == RESET);
      while (dht11_scan() == SET);
      for (i = 0; i < 5; i++)
      {
         buffer[ i] = dht11_read_byte();[ i]
      }

      while (dht11_scan() == RESET);
      dht11_gpio_output();
      DHT11_OUT_H;
      checksum = buffer[0] + buffer[1] + buffer[2] + buffer[3];
      if (checksum != buffer[4])
      {
         // checksum error
         return 1;
      }
}

return 0;
}
(三）主函數main.c代碼
[ i]
//
#include "stm32f10x.h"
#include "delay.h"
#include "digital.h"
#include "usart.h"
#include "dht11.h"
int main (void){
  SMG_Init();//
USART1_Config();
while(1){
u8 buffer[5];
  double hum;
double temp;
UART1SendByte(1);
  if (dht11_read_data(buffer) == 0)
      {
         hum = buffer[0] + buffer[1] / 10.0;
         temp = buffer[2] + buffer[3] / 10.0;
  Display_N(buffer[3]);//
      }
      printf("___{\"temperature\": %.2f, \"humidness\": %.2f}___\n", temp, hum);
      delay_us(200000);
}
}

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