stm32f103c8t6串口2发送AT+LOCATION=1指令给EC01g,得到GPS，解析GPS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，实现串口2发送AT指令给EC01g模块并解析GPS数据。

首先需要定义串口发送和接收的缓冲区大小：

#define RX_BUFFER_SIZE 256
#define TX_BUFFER_SIZE 256

然后定义串口发送和接收的缓冲区：

uint8_t rx_buffer[RX_BUFFER_SIZE];
uint8_t tx_buffer[TX_BUFFER_SIZE];

接下来需要初始化串口2：

void init_uart2(uint32_t baud_rate)
{
    // Enable GPIOA clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    
    // Enable USART2 clock
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
    
    // Configure USART2 Tx (PA2) as alternate function push-pull
    GPIO_InitTypeDef gpio_init;
    gpio_init.GPIO_Pin = GPIO_Pin_2;
    gpio_init.GPIO_Mode = GPIO_Mode_AF_PP;
    gpio_init.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &gpio_init);
    
    // Configure USART2 Rx (PA3) as input floating
    gpio_init.GPIO_Pin = GPIO_Pin_3;
    gpio_init.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &gpio_init);
    
    // Configure USART2
    USART_InitTypeDef usart_init;
    usart_init.USART_BaudRate = baud_rate;
    usart_init.USART_WordLength = USART_WordLength_8b;
    usart_init.USART_StopBits = USART_StopBits_1;
    usart_init.USART_Parity = USART_Parity_No;
    usart_init.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    usart_init.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(USART2, &usart_init);
    
    // Enable USART2
    USART_Cmd(USART2, ENABLE);
}

然后需要定义串口发送和接收的中断处理函数：

void USART2_IRQHandler(void)
{
    // Check if receive buffer not empty
    if (USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)
    {
        uint8_t data = USART_ReceiveData(USART2);
        rx_buffer[rx_index++] = data;
        
        // Check if receive buffer overflow
        if (rx_index >= RX_BUFFER_SIZE)
        {
            rx_index = 0;
            rx_overflow = true;
        }
    }
    
    // Check if transmission completed
    if (USART_GetITStatus(USART2, USART_IT_TC) != RESET)
    {
        USART_ClearITPendingBit(USART2, USART_IT_TC);
        tx_busy = false;
    }
}

接下来定义发送AT指令的函数：

void send_at_command(const char* command)
{
    // Wait for previous transmission to complete
    while (tx_busy)
    {
    }
    
    // Clear receive buffer and overflow flag
    rx_index = 0;
    rx_overflow = false;
    
    // Copy command to transmit buffer
    uint32_t len = strlen(command);
    memcpy(tx_buffer, command, len);
    
    // Send command
    USART_ITConfig(USART2, USART_IT_TC, DISABLE);
    USART_DMACmd(USART2, USART_DMAReq_Tx, DISABLE);
    USART_ClearITPendingBit(USART2, USART_IT_TC);
    DMA_Cmd(DMA1_Channel7, DISABLE);
    DMA1_Channel7->CNDTR = len;
    DMA1_Channel7->CPAR = (uint32_t)&USART2->DR;
    DMA1_Channel7->CMAR = (uint32_t)tx_buffer;
    DMA_Cmd(DMA1_Channel7, ENABLE);
    USART_DMACmd(USART2, USART_DMAReq_Tx, ENABLE);
    USART_ITConfig(USART2, USART_IT_TC, ENABLE);
    tx_busy = true;
    
    // Wait for response
    uint32_t timeout = 10000;
    while (timeout--)
    {
        if (rx_index > 0 && rx_buffer[rx_index - 1] == '\n')
        {
            break;
        }
        delay_ms(1);
    }
}

接下来定义解析GPS数据的函数：

void parse_gps_data(const char* data)
{
    char* token = strtok((char*)data, ",");
    int i = 0;
    while (token != NULL)
    {
        i++;
        if (i == 3)
        {
            // Latitude
            float lat_degrees = atof(token) / 100;
            float lat_minutes = fmod(atof(token), 100);
            float lat_decimal = lat_degrees + (lat_minutes / 60);
            printf("Latitude: %f\n", lat_decimal);
        }
        else if (i == 4)
        {
            // North or South
            if (strcmp(token, "N") == 0)
            {
                printf("Direction: North\n");
            }
            else if (strcmp(token, "S") == 0)
            {
                printf("Direction: South\n");
            }
        }
        else if (i == 5)
        {
            // Longitude
            float lon_degrees = atof(token) / 100;
            float lon_minutes = fmod(atof(token), 100);
            float lon_decimal = lon_degrees + (lon_minutes / 60);
            printf("Longitude: %f\n", lon_decimal);
        }
        else if (i == 6)
        {
            // East or West
            if (strcmp(token, "E") == 0)
            {
                printf("Direction: East\n");
            }
            else if (strcmp(token, "W") == 0)
            {
                printf("Direction: West\n");
            }
        }
        token = strtok(NULL, ",");
    }
}

最后，在main函数中调用上述函数：

int main()
{
    // Initialize UART2
    init_uart2(9600);
    
    // Send AT command to EC01g module
    send_at_command("AT+LOCATION=1\r\n");
    
    // Parse GPS data
    if (!rx_overflow)
    {
        parse_gps_data((const char*)rx_buffer);
    }
    
    while (1)
    {
    }
}