stm32f407与openmv串口通信代码标准库函数版本

以下是使用标准库函数的stm32f407与openmv串口通信代码示例：

#include "stm32f4xx.h"
#include <stdio.h>

#define USARTx                       USART2
#define USARTx_CLK                   RCC_APB1Periph_USART2
#define USARTx_TX_PIN                GPIO_Pin_2
#define USARTx_TX_GPIO_PORT          GPIOA
#define USARTx_TX_GPIO_CLK           RCC_AHB1Periph_GPIOA
#define USARTx_TX_SOURCE             GPIO_PinSource2
#define USARTx_TX_AF                 GPIO_AF_USART2
#define USARTx_RX_PIN                GPIO_Pin_3
#define USARTx_RX_GPIO_PORT          GPIOA
#define USARTx_RX_GPIO_CLK           RCC_AHB1Periph_GPIOA
#define USARTx_RX_SOURCE             GPIO_PinSource3
#define USARTx_RX_AF                 GPIO_AF_USART2
#define USARTx_IRQn                  USART2_IRQn

void USART_Config(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    /* Enable GPIO clock */
    RCC_AHB1PeriphClockCmd(USARTx_TX_GPIO_CLK | USARTx_RX_GPIO_CLK, ENABLE);

    /* Enable USART clock */
    RCC_APB1PeriphClockCmd(USARTx_CLK, ENABLE);

    /* Connect PXx to USARTx_Tx */
    GPIO_PinAFConfig(USARTx_TX_GPIO_PORT, USARTx_TX_SOURCE, USARTx_TX_AF);

    /* Connect PXx to USARTx_Rx */
    GPIO_PinAFConfig(USARTx_RX_GPIO_PORT, USARTx_RX_SOURCE, USARTx_RX_AF);

    /* Configure USART Tx and Rx as alternate function push-pull */
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

    GPIO_InitStructure.GPIO_Pin = USARTx_TX_PIN;
    GPIO_Init(USARTx_TX_GPIO_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = USARTx_RX_PIN;
    GPIO_Init(USARTx_RX_GPIO_PORT, &GPIO_InitStructure);

    /* USART configuration */
    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_Rx | USART_Mode_Tx;

    USART_Init(USARTx, &USART_InitStructure);

    /* Enable USART */
    USART_Cmd(USARTx, ENABLE);

    /* Configure USART interrupt */
    USART_ITConfig(USARTx, USART_IT_RXNE, ENABLE);

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

int fputc(int ch, FILE *f)
{
    /* Send a character to the USARTx */
    USART_SendData(USARTx, (uint8_t) ch);

    /* Loop until the end of transmission */
    while (USART_GetFlagStatus(USARTx, USART_FLAG_TC) == RESET);

    return ch;
}

void USARTx_IRQHandler(void)
{
    if (USART_GetITStatus(USARTx, USART_IT_RXNE) != RESET)
    {
        char rx_data = USART_ReceiveData(USARTx);
        printf("Received: %c\n", rx_data);
        USART_ClearITPendingBit(USARTx, USART_IT_RXNE);
    }
}

int main(void)
{
    USART_Config();

    while (1)
    {
        /* Send data to OpenMV */
        printf("Hello OpenMV!\n");
        delay_ms(1000);
    }
}

在此示例中，我们使用USART2与OpenMV进行通信。我们使用标准库函数进行USART2的初始化，并在中断处理程序中接收OpenMV发送的数据并打印到终端。在主函数中，我们使用printf函数向OpenMV发送数据。