51单片机 modbus 程序

抱歉，我是人工智能语言模型，我没有能力提供代码。但是，以下是一个基本的51单片机Modbus程序的示例代码，可以作为参考：

#include <reg51.h>

#define FOSC 11059200L
#define BAUD 9600
#define TIMER_1_5MS (65536 - (FOSC/12/1000*1.5))
#define TIMER_3_5CHAR (65536 - (FOSC/12/BAUD*3.5))

sbit RS485_EN = P2^0;
sbit LED = P2^1;

unsigned char code Modbus_Address = 0x01;
unsigned char code Modbus_Function = 0x03;
unsigned char code Modbus_DataAddress_High = 0x00;
unsigned char code Modbus_DataAddress_Low = 0x00;
unsigned char code Modbus_DataLength_High = 0x00;
unsigned char code Modbus_DataLength_Low = 0x01;
unsigned char code Modbus_CRC_High = 0x00;
unsigned char code Modbus_CRC_Low = 0x00;

unsigned int Timer1_Counter = 0;
unsigned int Timer3_Counter = 0;

void Init_Timer1(void)
{
    TMOD |= 0x10;
    TH1 = TIMER_1_5MS / 256;
    TL1 = TIMER_1_5MS % 256;
    EA = 1;
    ET1 = 1;
    TR1 = 1;
}

void Timer1_ISR(void) interrupt 3
{
    Timer1_Counter++;
    if (Timer1_Counter >= 2000)
    {
        Timer1_Counter = 0;
        LED = ~LED;
    }
}

void Init_Timer3(void)
{
    T3CON |= 0x30;
    TH3 = TIMER_3_5CHAR / 256;
    TL3 = TIMER_3_5CHAR % 256;
    ET3 = 1;
    TR3 = 1;
}

void Timer3_ISR(void) interrupt 14
{
    if (RI)
    {
        RI = 0;
        Timer3_Counter = 0;
    }
    if (TI)
    {
        TI = 0;
        RS485_EN = 0;
    }
    Timer3_Counter++;
    if (Timer3_Counter >= 100)
    {
        Timer3_Counter = 0;
        RS485_EN = 1;
    }
}

unsigned int Modbus_CRC(unsigned char *Data, unsigned int Length)
{
    unsigned int CRC = 0xFFFF;
    unsigned int i, j;

    for (i = 0; i < Length; i++)
    {
        CRC ^= Data[i];
        for (j = 0; j < 8; j++)
        {
            if (CRC & 0x0001)
            {
                CRC >>= 1;
                CRC ^= 0xA001;
            }
            else
            {
                CRC >>= 1;
            }
        }
    }

    return CRC;
}

void main()
{
    unsigned char Modbus_Buffer[8];
    unsigned int Modbus_CRC_Value;

    Init_Timer1();
    Init_Timer3();

    while (1)
    {
        if (Timer3_Counter >= 20)
        {
            Timer3_Counter = 0;

            Modbus_Buffer[0] = Modbus_Address;
            Modbus_Buffer[1] = Modbus_Function;
            Modbus_Buffer[2] = Modbus_DataAddress_High;
            Modbus_Buffer[3] = Modbus_DataAddress_Low;
            Modbus_Buffer[4] = Modbus_DataLength_High;
            Modbus_Buffer[5] = Modbus_DataLength_Low;
            Modbus_CRC_Value = Modbus_CRC(Modbus_Buffer, 6);
            Modbus_Buffer[6] = Modbus_CRC_Value >> 8;
            Modbus_Buffer[7] = Modbus_CRC_Value & 0xFF;

            SBUF = Modbus_Buffer[0];
            while (!TI);
            TI = 0;
            RS485_EN = 1;

            SBUF = Modbus_Buffer[1];
            while (!TI);
            TI = 0;
            RS485_EN = 1;

            SBUF = Modbus_Buffer[2];
            while (!TI);
            TI = 0;
            RS485_EN = 1;

            SBUF = Modbus_Buffer[3];
            while (!TI);
            TI = 0;
            RS485_EN = 1;

            SBUF = Modbus_Buffer[4];
            while (!TI);
            TI = 0;
            RS485_EN = 1;

            SBUF = Modbus_Buffer[5];
            while (!TI);
            TI = 0;
            RS485_EN = 1;

            SBUF = Modbus_Buffer[6];
            while (!TI);
            TI = 0;
            RS485_EN = 1;

            SBUF = Modbus_Buffer[7];
            while (!TI);
            TI = 0;
            RS485_EN = 1;
        }
    }
}