stm32时实判断串口连接状态实例

以下是一个使用定时器中断实现实时判断串口连接状态的示例：

#include "stm32f10x.h"
#include <stdbool.h>

#define UART_BAUD_RATE 9600
#define UART_RX_BUFFER_SIZE 32
#define UART_RX_TIMEOUT_MS 1000

volatile uint8_t uart_rx_buffer[UART_RX_BUFFER_SIZE];
volatile uint8_t uart_rx_index = 0;
volatile bool uart_rx_timeout = false;
volatile bool uart_connected = false;

void init_uart(void) {
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

    // 初始化UART引脚
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // 初始化UART
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
    USART_StructInit(&USART_InitStructure);
    USART_InitStructure.USART_BaudRate = UART_BAUD_RATE;
    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_Rx;
    USART_Init(USART2, &USART_InitStructure);
    USART_Cmd(USART2, ENABLE);

    // 初始化定时器
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
    TIM_TimeBaseStructure.TIM_Period = UART_RX_TIMEOUT_MS * 10;
    TIM_TimeBaseStructure.TIM_Prescaler = SystemCoreClock / 1000000 - 1;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM2, ENABLE);

    // 初始化NVIC
    NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

void USART2_IRQHandler(void) {
    if (USART_GetITStatus(USART2, USART_IT_RXNE) != RESET) {
        uint8_t data = USART_ReceiveData(USART2);
        if (uart_rx_index < UART_RX_BUFFER_SIZE) {
            uart_rx_buffer[uart_rx_index++] = data;
        }
        TIM_SetCounter(TIM2, 0);
    }
}

void TIM2_IRQHandler(void) {
    if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) {
        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
        uart_rx_timeout = true;
    }
}

bool is_uart_connected(void) {
    return uart_connected;
}

int main(void) {
    init_uart();
    while (1) {
        if (uart_rx_timeout) {
            if (uart_rx_index > 0) {
                uart_connected = true;
            } else {
                uart_connected = false;
            }
            uart_rx_timeout = false;
            uart_rx_index = 0;
        }
    }
}

在以上代码中，我们使用定时器TIM2来定时检测串口接收缓冲区中是否有数据。当串口接收空闲一段时间后，定时器中断会被触发，此时判断串口连接状态。如果一段时间内没有接收到数据，则认为串口连接状态异常。同时，在USART2中断处理函数中，我们需要实现接收串口数据并将其存储到缓冲区中。

最后，在主函数中我们可以调用is_uart_connected函数来获取串口连接状态。