STM32和gps时间同步pps检查代码

以下是基于STM32和GPS模块实现时间同步和PPS检测的示例代码：

首先，需要配置STM32的UART和外部中断来接收GPS模块的NMEA协议数据和PPS信号。

#include "stm32f4xx.h"
#include "stdio.h"

/* GPS串口定义 */
#define GPS_USART                   USART1
#define GPS_USART_CLK               RCC_APB2Periph_USART1
#define GPS_USART_CLK_INIT          RCC_APB2PeriphClockCmd
#define GPS_USART_IRQn              USART1_IRQn
#define GPS_USART_IRQHandler        USART1_IRQHandler
#define GPS_USART_BAUDRATE          9600

/* GPS定位信息结构体定义 */
typedef struct {
    float latitude;     // 纬度
    float longitude;    // 经度
    float altitude;     // 海拔高度
    float speed;        // 速度
    float course;       // 航向
    int date;           // 日期（YYYYMMDD）
    int time;           // 时间（HHMMSS.SSS）
} gps_info_t;

/* GPS定位信息变量定义 */
gps_info_t gps_info = {0};

/* PPS信号检测变量定义 */
volatile uint32_t pps_count = 0;
volatile uint32_t last_pps_time = 0;
volatile uint8_t is_pps_detected = 0;

/* GPS定位信息解析函数 */
void gps_parse(char *str)
{
    float lat_degree, lat_minute, lon_degree, lon_minute;
    char lat_direction, lon_direction;
    int year, month, day, hour, minute, second;

    if (sscanf(str, "$GPGGA,%*f,%2d%2d.%*f,%c,%3d%2d.%*f,%c,%*d,%*d,%.1f,%*f,M,%.1f,M,,", 
               &year, &month, &lat_degree, &lat_minute, &lat_direction, &gps_info.altitude, &gps_info.latitude) == 7) {
        // 解析纬度
        gps_info.latitude = (float)lat_degree + lat_minute / 60.0;
        if (lat_direction == 'S') {
            gps_info.latitude = -gps_info.latitude;
        }

        if (sscanf(str, "$GPRMC,%2d%2d%2d.%*f,A,%3d%2d.%*f,%c,%4d%2d%2d,,,%*s*%*s", 
                   &hour, &minute, &second, &lon_degree, &lon_minute, &lon_direction, &year, &month, &day) == 9) {
            // 解析经度
            gps_info.longitude = (float)lon_degree + lon_minute / 60.0;
            if (lon_direction == 'W') {
                gps_info.longitude = -gps_info.longitude;
            }

            // 解析时间
            gps_info.time = hour * 10000 + minute * 100 + second;

            // 解析日期
            gps_info.date = year * 10000 + month * 100 + day;
        }
    }
}

/* GPS串口接收中断处理函数 */
void GPS_USART_IRQHandler(void)
{
    if (USART_GetITStatus(GPS_USART, USART_IT_RXNE) != RESET) {
        static char gps_buffer[128] = {0};
        static uint8_t gps_index = 0;

        char ch = USART_ReceiveData(GPS_USART) & 0xff;

        if (ch == '$') {
            gps_index = 0;
            memset(gps_buffer, 0, sizeof(gps_buffer));
        }

        gps_buffer[gps_index++] = ch;
        if (ch == '\n') {
            gps_parse(gps_buffer);
        }

        USART_ClearITPendingBit(GPS_USART, USART_IT_RXNE);
    }
}

/* PPS信号检测外部中断处理函数 */
void EXTI0_IRQHandler(void)
{
    if (EXTI_GetITStatus(EXTI_Line0) != RESET) {
        uint32_t current_time = TIM_GetCounter(TIM2);
        if (current_time - last_pps_time > 1000) {
            pps_count++;
            is_pps_detected = 1;
        }
        last_pps_time = current_time;

        EXTI_ClearITPendingBit(EXTI_Line0);
    }
}

/* 定时器2初始化函数 */
void TIM2_Init(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_TimeBaseStructure.TIM_Period = 0xFFFFFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 84 - 1;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

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

    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

    TIM_Cmd(TIM2, ENABLE);
}

/* 外部中断初始化函数 */
void EXTI_Init(void)
{
    EXTI_InitTypeDef EXTI_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);

    EXTI_InitStructure.EXTI_Line = EXTI_Line0;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

int main(void)
{
    USART_InitTypeDef USART_InitStructure;

    /* GPS串口初始化 */
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB2PeriphClockCmd(GPS_USART_CLK, ENABLE);

    GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_USART1);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_USART1);

    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    USART_InitStructure.USART_BaudRate = GPS_USART_BAUDRATE;
    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_Mode_Tx;
    USART_Init(GPS_USART, &USART_InitStructure);

    USART_ITConfig(GPS_USART, USART_IT_RXNE, ENABLE);
    USART_Cmd(GPS_USART, ENABLE);

    /* PPS检测定时器和外部中断初始化 */
    TIM2_Init();
    EXTI_Init();

    while (1) {
        if (is_pps_detected) {
            is_pps_detected = 0;

            // 在这里添加PPS信号检测后的处理代码
        }

        // 在这里添加GPS定位信息处理代码
    }
}

在主函数中，通过解析GPS模块发送的NMEA协议数据，可以获取到GPS定位信息。同时，使用定时器和外部中断来检测PPS信号，计算出两个PPS信号之间的时间差，从而实现时间同步。

需要注意的是，PPS信号的检测精度和稳定性对于时间同步的准确性有很大的影响，因此需要根据实际需求进行优化和调整。