STM32F407与openmv串口通信标准库函数通过帧头

串口通信时，可以通过帧头来标识数据包的开始，从而实现数据包的可靠传输。在使用标准库函数进行串口通信时，可以通过以下步骤来实现基于帧头的通信：

1. 定义数据包格式，包括帧头和数据部分。例如，可以定义帧头为一个字节的固定值，数据部分为可变长度的数据。

2. 在发送方，使用标准库函数将数据包格式化为字节流，并通过串口发送出去。

3. 在接收方，使用标准库函数从串口读取字节流，逐字节解析数据包。当读取到帧头时，表示一个新的数据包开始，可以开始接收数据。当接收完整个数据包后，可以对数据进行处理，并准备接收下一个数据包。

需要注意的是，基于帧头的通信可以增加数据包的可靠性，但也会增加通信的开销。在实际应用中，需要根据具体情况来选择合适的通信方式。

相关问题

stm32f407与openmv串口通信代码标准库函数版本通过帧头

以下是基于标准库函数的STM32F407与OpenMV串口通信代码，通过帧头进行数据传输：

STM32F407代码：

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

#define RX_BUFFER_SIZE  64

uint8_t rx_buffer[RX_BUFFER_SIZE];
uint8_t rx_index = 0;
uint8_t rx_complete = 0;

void USART2_IRQHandler(void) {
    if (USART_GetITStatus(USART2, USART_IT_RXNE) != RESET) {
        uint8_t ch = USART_ReceiveData(USART2);
        
        if (rx_index == 0 && ch != 0xAA) {
            return;
        }
        
        rx_buffer[rx_index] = ch;
        rx_index++;
        
        if (rx_index >= RX_BUFFER_SIZE) {
            rx_index = 0;
        }
        
        if (rx_index == 4 && rx_buffer[1] == 0x01 && rx_buffer[2] == 0x02) {
            rx_complete = 1;
        }
    }
}

void USART2_Init(void) {
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
    
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2);
    
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    
    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(USART2, &USART_InitStructure);
    
    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
    
    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);
}

void USART2_SendChar(uint8_t ch) {
    while (USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET);
    USART_SendData(USART2, ch);
}

void USART2_SendFrame(uint8_t *buffer, uint8_t size) {
    USART2_SendChar(0xAA);
    USART2_SendChar(size);
    for (uint8_t i = 0; i < size; i++) {
        USART2_SendChar(buffer[i]);
    }
}

int main(void) {
    USART2_Init();
    
    while (1) {
        if (rx_complete) {
            uint8_t size = rx_buffer[3];
            uint8_t buffer[size];
            memcpy(buffer, &rx_buffer[4], size);
            // 处理接收到的数据
            
            rx_index = 0;
            rx_complete = 0;
        }
    }
}

OpenMV代码：

import time
from struct import pack, unpack

uart = UART(3, 115200)
uart.init(115200, bits=8, parity=None, stop=1)

# 发送帧
def send_frame(data):
    size = len(data)
    header = pack('BBB', 0xAA, 0x01, 0x02)
    frame = header + pack('B'*size, *data)
    uart.write(frame)

while(True):
    if uart.any():
        data = uart.read(64)
        if data[0] == 0xAA and data[1] == 0x01 and data[2] == 0x02:
            size = data[3]
            frame = unpack('B'*size, data[4:size+4])
            # 处理接收到的数据

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。