用IAR写出STM32利用定时器4中断处理功能，实现每隔2s，读取实现将温湿度传感器DHT11的值上传到串口小助手

好的，以下是用IAR写出STM32利用定时器4中断处理功能，实现每隔2s，读取实现将温湿度传感器DHT11的值上传到串口小助手的示例代码：

#include "stm32f10x.h"
#include "stdio.h"

#define DHT11_PIN GPIO_Pin_0
#define DHT11_PORT GPIOA

uint8_t DHT11_Data[5];

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    GPIO_InitStructure.GPIO_Pin = DHT11_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(DHT11_PORT, &GPIO_InitStructure);
}

void Delay_us(uint32_t n)
{
    for (; n > 0; n--)
    {
        __nop();
        __nop();
        __nop();
        __nop();
        __nop();
        __nop();
        __nop();
        __nop();
        __nop();
        __nop();
    }
}

void DHT11_Start(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    GPIO_InitStructure.GPIO_Pin = DHT11_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(DHT11_PORT, &GPIO_InitStructure);
    GPIO_SetBits(DHT11_PORT, DHT11_PIN);
    Delay_us(1000);
    GPIO_ResetBits(DHT11_PORT, DHT11_PIN);
    Delay_us(18000);
    GPIO_SetBits(DHT11_PORT, DHT11_PIN);
}

uint8_t DHT11_Check_Response(void)
{
    uint8_t Response = 0;
    uint16_t Time_Counter = 0;
    while (GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN))
    {
        Time_Counter++;
        Delay_us(1);
        if (Time_Counter > 1000)
        {
            return 1;
        }
    }
    Time_Counter = 0;
    while (!GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN))
    {
        Time_Counter++;
        Delay_us(1);
        if (Time_Counter > 1000)
        {
            return 1;
        }
    }
    Time_Counter = 0;
    while (GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN))
    {
        Time_Counter++;
        Delay_us(1);
        if (Time_Counter > 1000)
        {
            return 1;
        }
    }
    return 0;
}

uint8_t DHT11_Read_Byte(void)
{
    uint8_t i, j;
    uint8_t Data = 0;
    for (j = 0; j < 8; j++)
    {
        while (!GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN))
            ;
        Delay_us(40);
        if (GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN))
        {
            Data |= (1 << (7 - j));
        }
        while (GPIO_ReadInputDataBit(DHT11_PORT, DHT11_PIN))
            ;
    }
    return Data;
}

void DHT11_Read_Data(void)
{
    uint8_t i;
    DHT11_Start();
    if (DHT11_Check_Response())
    {
        printf("DHT11 Check Response Failed\r\n");
        return;
    }
    for (i = 0; i < 5; i++)
    {
        DHT11_Data[i] = DHT11_Read_Byte();
    }
}

void USART_Configuration(void)
{
    USART_InitTypeDef USART_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    USART_InitStructure.USART_BaudRate = 115200;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);
    USART_Cmd(USART1, ENABLE);
}

void NVIC_Configuration(void)
{
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

void TIM_Configuration(void)
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_TimeBaseStructure.TIM_Period = 1999;
    TIM_TimeBaseStructure.TIM_Prescaler = 35999;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
    TIM_ITConfig(TIM4, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM4, ENABLE);
}

void TIM4_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM4, TIM_IT_Update) == SET)
    {
        DHT11_Read_Data();
        printf("Temperature: %dC  Humidity: %d%%\r\n", DHT11_Data[2], DHT11_Data[0]);
        TIM_ClearITPendingBit(TIM4, TIM_IT_Update);
    }
}

int main(void)
{
    GPIO_Configuration();
    USART_Configuration();
    NVIC_Configuration();
    TIM_Configuration();
    while (1)
        ;
}

其中，我们使用定时器4产生2s的中断，中断处理函数 `TIM4_IRQHandler()` 中读取 DHT11 的数据，并通过串口 `USART1` 将数据上传到串口小助手。需要注意的是，在读取 DHT11 数据时，需要先发送起始信号，然后进行数据的接收和解析，具体细节请参考代码中的注释。