stm32f103c8t6串口2发送AT+LOCATION=1指令给EC01g,解析缓冲区的经纬度数据，stm32库函数版本的代码

以下是使用stm32库函数版本的代码，实现通过串口2发送AT指令给EC01g模块，并解析缓冲区中的经纬度数据：

#include "stm32f10x.h"
#include <stdio.h>
#include <string.h>

#define GPS_BUFFER_SIZE 128

char gps_buffer[GPS_BUFFER_SIZE];
uint8_t gps_buffer_index = 0;

void USART2_IRQHandler(void)
{
    if (USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)
    {
        char c = USART_ReceiveData(USART2);
        gps_buffer[gps_buffer_index++] = c;
        if (gps_buffer_index >= GPS_BUFFER_SIZE)
        {
            gps_buffer_index = 0;
        }
    }
}

void USART2_SendString(char *str)
{
    while (*str)
    {
        USART_SendData(USART2, *str++);
        while (USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET);
    }
}

void USART2_SendATCommand(char *cmd)
{
    USART2_SendString("AT+");
    USART2_SendString(cmd);
    USART2_SendString("\r\n");
}

int main(void)
{
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    USART_DeInit(USART2);

    USART_InitStructure.USART_BaudRate = 9600;
    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(USART2, &USART_InitStructure);

    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);

    USART_Cmd(USART2, ENABLE);
    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

    while (1)
    {
        USART2_SendATCommand("LOCATION=1");
        Delay(1000);

        if (strstr(gps_buffer, "+LOCATION:") != NULL)
        {
            char *p = strstr(gps_buffer, ",");
            if (p != NULL)
            {
                float latitude = atof(p + 1);
                p = strstr(p + 1, ",");
                if (p != NULL)
                {
                    float longitude = atof(p + 1);
                    printf("Latitude: %f, Longitude: %f\n", latitude, longitude);
                }
            }
        }

        memset(gps_buffer, 0, GPS_BUFFER_SIZE);
        gps_buffer_index = 0;

        Delay(5000);
    }
}

在上述代码中，使用USART2发送AT指令给EC01g模块，并使用USART2接收EC01g模块返回的数据，其中使用了中断接收方式。

在接收到EC01g模块返回的数据后，使用`strstr()`函数查找缓冲区中是否包含"+LOCATION:"字段，如果有，则解析经纬度数据并打印出来。在解析经纬度数据时，使用了`atof()`函数将字符串转换为浮点数。

需要注意的是，在使用`atof()`函数时，需要包含头文件`<stdlib.h>`。另外，在本例中使用了一个自定义的延时函数`Delay()`，需要自行实现。