dht11通过uart通信协议接收数据的代码 keil

以下是基于Keil MDK的DHT11通过UART通信协议接收数据的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include "stm32f10x.h"
#include "uart.h"

#define DHT11_PORT GPIOA
#define DHT11_PIN GPIO_Pin_0

void delay_us(uint32_t us)
{
    uint32_t i;
    for(i = 0; i < us * 8; i++);
}

uint8_t read_byte(void)
{
    uint8_t byte = 0;
    uint8_t i;

    for(i = 0; i < 8; i++)
    {
        while(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN) == RESET); //等待高电平
        delay_us(30); //等待30us
        if(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN) == SET) //如果为高电平，表示为1
        {
            byte |= (1 << (7 - i));
            while(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN) == SET); //等待低电平
        }
    }

    return byte;
}

uint8_t dht11_receive_data(float *temperature, float *humidity)
{
    uint8_t data[5] = {0};
    uint8_t i;
    uint8_t checksum = 0;
    
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Pin = DHT11_PIN;
    GPIO_Init(DHT11_PORT, &GPIO_InitStructure); //设置为输出模式
    
    GPIO_SetBits(DHT11_PORT, DHT11_PIN);
    delay_us(500); //拉高至少500us
    GPIO_ResetBits(DHT11_PORT, DHT11_PIN);
    delay_us(18000); //拉低18ms
    GPIO_SetBits(DHT11_PORT, DHT11_PIN);
    delay_us(30); //等待30us

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(DHT11_PORT, &GPIO_InitStructure); //设置为上拉输入模式

    if(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN) == RESET) //DHT11响应
    {
        while(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN) == RESET); //等待低电平结束
        while(GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN) == SET); //等待高电平开始
        for(i = 0; i < 5; i++)
        {
            data[i] = read_byte();
        }
        for(i = 0; i < 4; i++) //计算校验和
        {
            checksum += data[i];
        }
        if(checksum == data[4]) //校验和正确
        {
            *humidity = (float)data[0] + (float)data[1] / 10.0;
            *temperature = (float)data[2] + (float)data[3] / 10.0;
            return 0; //返回0表示读取成功
        }
        else //校验和错误
        {
            return 1; //返回1表示校验和错误
        }
    }

    return 2; //返回2表示DHT11没有响应
}

int main()
{
    float temperature, humidity;
    uint8_t result;
  
    uart_init(USART1, 115200); //初始化串口
    printf("DHT11 Test\r\n");

    while(1)
    {
        result = dht11_receive_data(&temperature, &humidity); //读取数据
        if(result == 0) //读取成功
        {
            printf("Temperature: %.1fC, Humidity: %.1f%%\r\n", temperature, humidity);
        }
        else if(result == 1) //校验和错误
        {
            printf("Checksum error!\r\n");
        }
        else //DHT11没有响应
        {
            printf("No response!\r\n");
        }
        delay_us(2000000); //等待2s
    }
}

注：上述代码中用到了uart.h文件，需要自行添加。