嵌入式stm32f103 modbus RS232通讯程序

以下是一个嵌入式stm32f103 modbus RS232通讯程序的示例：

#include "stm32f10x.h"
#include "modbus.h"

#define USART_TX_BUFFER_SIZE 256
#define USART_RX_BUFFER_SIZE 256

uint8_t usart_tx_buffer[USART_TX_BUFFER_SIZE];
uint8_t usart_tx_index = 0;
uint8_t usart_tx_length = 0;

uint8_t usart_rx_buffer[USART_RX_BUFFER_SIZE];
uint8_t usart_rx_index = 0;
uint8_t usart_rx_length = 0;

void USART1_IRQHandler(void)
{
    if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
    {
        usart_rx_buffer[usart_rx_index++] = USART_ReceiveData(USART1);
        if (usart_rx_index >= USART_RX_BUFFER_SIZE)
            usart_rx_index = 0;
        usart_rx_length++;
        USART_ClearITPendingBit(USART1, USART_IT_RXNE);
    }

    if (USART_GetITStatus(USART1, USART_IT_TXE) != RESET)
    {
        if (usart_tx_length > 0)
        {
            USART_SendData(USART1, usart_tx_buffer[usart_tx_index++]);
            if (usart_tx_index >= USART_TX_BUFFER_SIZE)
                usart_tx_index = 0;
            usart_tx_length--;
        }
        else
        {
            USART_ITConfig(USART1, USART_IT_TXE, DISABLE);
        }
        USART_ClearITPendingBit(USART1, USART_IT_TXE);
    }
}

void usart_send_data(uint8_t *data, uint8_t length)
{
    if (length > USART_TX_BUFFER_SIZE)
        length = USART_TX_BUFFER_SIZE;
    for (uint8_t i = 0; i < length; i++)
    {
        usart_tx_buffer[usart_tx_index++] = data[i];
        if (usart_tx_index >= USART_TX_BUFFER_SIZE)
            usart_tx_index = 0;
    }
    usart_tx_length = length;
    USART_ITConfig(USART1, USART_IT_TXE, ENABLE);
}

void modbus_send_data(uint8_t *data, uint8_t length)
{
    usart_send_data(data, length);
}

uint8_t modbus_receive_data(uint8_t *data, uint8_t length)
{
    uint8_t len = 0;
    while (len < length && usart_rx_length > 0)
    {
        data[len++] = usart_rx_buffer[usart_rx_index++];
        if (usart_rx_index >= USART_RX_BUFFER_SIZE)
            usart_rx_index = 0;
        usart_rx_length--;
    }
    return len;
}

int main(void)
{
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_USART1, ENABLE);

    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    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_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    USART_StructInit(&USART_InitStructure);
    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(USART1, &USART_InitStructure);

    USART_Cmd(USART1, ENABLE);

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

    modbus_init();

    while (1)
    {
        modbus_poll();
    }
}

在此示例中，我们使用STM32F103芯片和USART1串口。我们实现了一个简单的usart_send_data函数，它用于将数据发送到USART1。我们还实现了一个modbus_send_data函数，它只是调用usart_send_data函数。 modbus_receive_data函数从USART1接收数据。我们使用了一个usart_rx_buffer数组来存储接收到的数据。 在主函数中，我们首先初始化USART1和modbus。然后我们在一个while循环中调用modbus_poll函数，它将检查是否有任何modbus命令需要处理。 USART1_IRQHandler函数是USART1的中断处理程序。在接收到数据时，我们将其存储在usart_rx_buffer数组中。在发送数据时，我们从usart_tx_buffer数组中读取数据。当发送完成时，我们禁用USART1的TXE中断。