uart_init.USART_WordLength = serial_config->serial_word_length;

这段代码的作用是将一个叫做uart_init的结构体变量中的USART_WordLength成员变量设置为一个叫做serial_config的结构体变量中的serial_word_length成员变量的值，以便在后续使用该USART通信接口进行数据传输时，将数据位设置为serial_word_length的值。USART_WordLength是USART通信接口的数据位寄存器，用于控制USART通信接口每个数据帧的数据位数。而serial_config->serial_word_length则是一个存储了数据位数的变量，表示使用该数据位数进行数据传输。通过将serial_config->serial_word_length的值赋给uart_init.USART_WordLength，可以将数据位设置为serial_word_length的值，以便后续使用该USART通信接口进行数据传输。

相关问题

stm32双串口rtthread程序

以下是一个基于RT-Thread的双串口STM32程序示例：

#include <rtthread.h>
#include "stm32f10x.h"

#define USART1_GPIO_TX   GPIO_Pin_9
#define USART1_GPIO_RX   GPIO_Pin_10
#define USART2_GPIO_TX   GPIO_Pin_2
#define USART2_GPIO_RX   GPIO_Pin_3

#define USART1_RX_BUFSIZE  128
#define USART2_RX_BUFSIZE  128

static rt_uint8_t usart1_rx_buffer[USART1_RX_BUFSIZE];
static rt_uint8_t usart2_rx_buffer[USART2_RX_BUFSIZE];

static struct rt_semaphore usart1_rx_sem;
static struct rt_semaphore usart2_rx_sem;

static struct rt_serial_device serial1;
static struct rt_serial_device serial2;

static void USART1_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = USART1_GPIO_TX;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = USART1_GPIO_RX;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    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(USART1, &USART_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);

    USART_Cmd(USART1, ENABLE);
}

static void USART2_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

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

    GPIO_InitStructure.GPIO_Pin = USART2_GPIO_TX;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = USART2_GPIO_RX;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    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);

    NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

    USART_Cmd(USART2, ENABLE);
}

static rt_err_t serial1_configure(struct rt_serial_device *serial, struct serial_configure *cfg)
{
    USART_InitTypeDef USART_InitStructure;

    USART_InitStructure.USART_BaudRate = cfg->baud_rate;
    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;

    if (cfg->data_bits == DATA_BITS_9) {
        USART_InitStructure.USART_WordLength = USART_WordLength_9b;
    }

    if (cfg->stop_bits == STOP_BITS_2) {
        USART_InitStructure.USART_StopBits = USART_StopBits_2;
    }

    if (cfg->parity == PARITY_ODD) {
        USART_InitStructure.USART_Parity = USART_Parity_Odd;
    } else if (cfg->parity == PARITY_EVEN) {
        USART_InitStructure.USART_Parity = USART_Parity_Even;
    }

    USART_Init(USART1, &USART_InitStructure);

    return RT_EOK;
}

static rt_err_t serial2_configure(struct rt_serial_device *serial, struct serial_configure *cfg)
{
    USART_InitTypeDef USART_InitStructure;

    USART_InitStructure.USART_BaudRate = cfg->baud_rate;
    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;

    if (cfg->data_bits == DATA_BITS_9) {
        USART_InitStructure.USART_WordLength = USART_WordLength_9b;
    }

    if (cfg->stop_bits == STOP_BITS_2) {
        USART_InitStructure.USART_StopBits = USART_StopBits_2;
    }

    if (cfg->parity == PARITY_ODD) {
        USART_InitStructure.USART_Parity = USART_Parity_Odd;
    } else if (cfg->parity == PARITY_EVEN) {
        USART_InitStructure.USART_Parity = USART_Parity_Even;
    }

    USART_Init(USART2, &USART_InitStructure);

    return RT_EOK;
}

static rt_err_t serial1_control(struct rt_serial_device *serial, int cmd, void *arg)
{
    switch (cmd) {
    case RT_DEVICE_CTRL_CLR_INT:
        USART_ITConfig(USART1, USART_IT_RXNE, DISABLE);
        break;
    case RT_DEVICE_CTRL_SET_INT:
        USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
        break;
    }

    return RT_EOK;
}

static rt_err_t serial2_control(struct rt_serial_device *serial, int cmd, void *arg)
{
    switch (cmd) {
    case RT_DEVICE_CTRL_CLR_INT:
        USART_ITConfig(USART2, USART_IT_RXNE, DISABLE);
        break;
    case RT_DEVICE_CTRL_SET_INT:
        USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
        break;
    }

    return RT_EOK;
}

static int serial1_putc(struct rt_serial_device *serial, char c)
{
    USART_SendData(USART1, (uint16_t)c);
    while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

    return 1;
}

static int serial2_putc(struct rt_serial_device *serial, char c)
{
    USART_SendData(USART2, (uint16_t)c);
    while (USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET);

    return 1;
}

static int serial1_getc(struct rt_serial_device *serial)
{
    rt_int32_t ch = -1;

    rt_sem_take(&usart1_rx_sem, RT_WAITING_FOREVER);

    if (serial1.rx_index > 0) {
        ch = serial1.rx_buffer[0];
        rt_memcpy(serial1.rx_buffer, serial1.rx_buffer + 1, serial1.rx_index - 1);
        serial1.rx_index--;
    }

    return ch;
}

static int serial2_getc(struct rt_serial_device *serial)
{
    rt_int32_t ch = -1;

    rt_sem_take(&usart2_rx_sem, RT_WAITING_FOREVER);

    if (serial2.rx_index > 0) {
        ch = serial2.rx_buffer[0];
        rt_memcpy(serial2.rx_buffer, serial2.rx_buffer + 1, serial2.rx_index - 1);
        serial2.rx_index--;
    }

    return ch;
}

static const struct rt_uart_ops serial1_ops = {
    serial1_configure,
    serial1_control,
    serial1_putc,
    serial1_getc,
};

static const struct rt_uart_ops serial2_ops = {
    serial2_configure,
    serial2_control,
    serial2_putc,
    serial2_getc,
};

static void USART1_IRQHandler(void)
{
    if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET) {
        rt_int32_t ch = USART_ReceiveData(USART1);

        if (serial1.rx_index < USART1_RX_BUFSIZE) {
            serial1.rx_buffer[serial1.rx_index++] = ch;
        }

        rt_sem_release(&usart1_rx_sem);

        USART_ClearITPendingBit(USART1, USART_IT_RXNE);
    }
}

static void USART2_IRQHandler(void)
{
    if (USART_GetITStatus(USART2, USART_IT_RXNE) != RESET) {
        rt_int32_t ch = USART_ReceiveData(USART2);

        if (serial2.rx_index < USART2_RX_BUFSIZE) {
            serial2.rx_buffer[serial2.rx_index++] = ch;
        }

        rt_sem_release(&usart2_rx_sem);

        USART_ClearITPendingBit(USART2, USART_IT_RXNE);
    }
}

void usart_init(void)
{
    rt_sem_init(&usart1_rx_sem, "usart1_rx", 0, RT_IPC_FLAG_FIFO);
    rt_sem_init(&usart2_rx_sem, "usart2_rx", 0, RT_IPC_FLAG_FIFO);

    USART1_Configuration();
    USART2_Configuration();

    rt_memset(&serial1, 0, sizeof(serial1));
    rt_memset(&serial2, 0, sizeof(serial2));

    serial1.ops = &serial1_ops;
    serial1.config.baud_rate = 115200;
    serial1.config.data_bits = DATA_BITS_8;
    serial1.config.stop_bits = STOP_BITS_1;
    serial1.config.parity = PARITY_NONE;

    serial2.ops = &serial2_ops;
    serial2.config.baud_rate = 115200;
    serial2.config.data_bits = DATA_BITS_8;
    serial2.config.stop_bits = STOP_BITS_1;
    serial2.config.parity = PARITY_NONE;

    rt_hw_serial_register(&serial1, "usart1", RT_DEVICE_FLAG_RDWR);
    rt_hw_serial_register(&serial2, "usart2", RT_DEVICE_FLAG_RDWR);
}

该程序中使用了RT-Thread的串口设备框架，同时实现了双串口接收中断，并通过信号量来触发接收完成事件。在初始化时，定义了两个串口设备serial1和serial2，分别对应USART1和USART2。在serial1和serial2的配置、控制、读写函数中，分别对应了STM32的USART1和USART2。在USART1_IRQHandler和USART2_IRQHandler中，分别判断是否是接收中断，并将接收到的字符存储到对应的缓冲区中，并通过信号量触发接收完成事件。最后，通过rt_hw_serial_register将serial1和serial2注册为RT-Thread串口设备，实现对串口的操作。

stm32与openmv通信

STM32和OpenMV的通信可以通过串口实现。以下是一个简单的示例代码：

在STM32上，初始化串口：

#include "stm32f4xx_hal.h"
UART_HandleTypeDef huart2;

void SystemClock_Config(void);

int main(void)
{
  HAL_Init();
  SystemClock_Config();

  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_USART2_CLK_ENABLE();

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  GPIO_InitStruct.Pin = GPIO_PIN_2|GPIO_PIN_3;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
}

void HAL_UART_MspInit(UART_HandleTypeDef* uartHandle)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(uartHandle->Instance==USART2)
  {
    __HAL_RCC_USART2_CLK_ENABLE();
    __HAL_RCC_GPIOA_CLK_ENABLE();

    GPIO_InitStruct.Pin = GPIO_PIN_2|GPIO_PIN_3;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
  }
}

void HAL_UART_MspDeInit(UART_HandleTypeDef* uartHandle)
{
  if(uartHandle->Instance==USART2)
  {
    __HAL_RCC_USART2_CLK_DISABLE();

    HAL_GPIO_DeInit(GPIOA, GPIO_PIN_2|GPIO_PIN_3);
  }
}

在OpenMV上，初始化串口：

import time, serial

uart = serial.Serial("/dev/ttyACM0", baudrate=115200, timeout=1000)

while(True):
    if (uart.any()):
        data = uart.readline()
        print(data)

在STM32上，向OpenMV发送数据：

char data[] = "Hello OpenMV!\r\n";
HAL_UART_Transmit(&huart2, (uint8_t*)data, strlen(data), 1000);

在OpenMV上，向STM32发送数据：

uart.write("Hello STM32!\r\n")

注意事项：

1. 在OpenMV上，串口的名称可能会有所不同，需要根据实际情况进行更改。

2. 在使用串口通信时，需要将STM32和OpenMV的地线连接在一起。

3. 在使用串口通信时，需要确保STM32和OpenMV的波特率相同。