在Modbus RTU中同时进行读取和写入操作

#include "ModbusRTU.h"
#include <iostream>
#include <cstring> // For memcpy

ModbusRTU::ModbusRTU(boost::asio::io_service& io_service, const std::string& port_name)
    : serial(io_service, port_name) {
    serial.set_option(boost::asio::serial_port_base::baud_rate(9600));
    serial.set_option(boost::asio::serial_port_base::character_size(8));
    serial.set_option(boost::asio::serial_port_base::parity(boost::asio::serial_port_base::parity::none));
    serial.set_option(boost::asio::serial_port_base::stop_bits(boost::asio::serial_port_base::stop_bits::one));
}

template<typename T>
void ModbusRTU::writeData(uint8_t slave_id, uint8_t function_code, uint16_t start_address, T value) {
    uint8_t frame[8 + sizeof(T)];
    frame[0] = slave_id;
    frame[1] = function_code;
    frame[2] = (start_address >> 8) & 0xFF;
    frame[3] = start_address & 0xFF;

    std::memcpy(&frame[4], &value, sizeof(T));

    uint16_t crc = calculateCRC(frame, 4 + sizeof(T));
    frame[4 + sizeof(T)] = crc & 0xFF;
    frame[5 + sizeof(T)] = (crc >> 8) & 0xFF;

    boost::asio::write(serial, boost::asio::buffer(frame, 6 + sizeof(T)));
}

template<typename T>
T ModbusRTU::readData(uint8_t slave_id, uint8_t function_code, uint16_t start_address, uint16_t num_registers) {
    uint8_t frame[8];
    frame[0] = slave_id;
    frame[1] = function_code;
    frame[2] = (start_address >> 8) & 0xFF;
    frame[3] = start_address & 0xFF;
    frame[4] = (num_registers >> 8) & 0xFF;
    frame[5] = num_registers & 0xFF;
    uint16_t crc = calculateCRC(frame, 6);
    frame[6] = crc & 0xFF;
    frame[7] = (crc >> 8) & 0xFF;

    boost::asio::write(serial, boost::asio::buffer(frame, 8));

    uint8_t response[256];
    size_t length = serial.read_some(boost::asio::buffer(response, 256));
    if (length > 0 && response[1] == function_code) {
        T result = 0;
        for (size_t i = 0; i < sizeof(T); ++i) {
            reinterpret_cast<uint8_t*>(&result)[i] = response[3 + i];
        }
        return result;
    }
    else {
        std::cerr << "错误：无效的响应或没有收到响应。" << std::endl;
    }
    return T(); // 返回类型 T 的默认值
}

uint16_t ModbusRTU::calculateCRC(const uint8_t* data, size_t length) {
    uint16_t crc = 0xFFFF;
    for (size_t i = 0; i < length; ++i) {
        crc ^= data[i];
        for (int j = 0; j < 8; ++j) {
            if (crc & 1) crc = (crc >> 1) ^ 0xA001;
            else crc >>= 1;
        }
    }
    return crc;
}



void main() {
    try {
        boost::asio::io_service io_service;
        ModbusRTU modbus(io_service, "/dev/ttyS0"); // 根据你的实际串口设备调整

        uint8_t slave_id = 1;  // 从站地址
        uint16_t start_address = 0x0001; // 起始寄存器地址
        uint16_t value_to_write = 12345;  // 要写入的值

        // 写入数据
        modbus.writeData<uint16_t>(slave_id, 0x06, start_address, value_to_write); // 0x06 是写单寄存器的功能码

        std::cout << "数据已写入。" << std::endl;

        // 读取数据
        uint16_t read_value = modbus.readData<uint16_t>(slave_id, 0x03, start_address, 1); // 0x03 是读保持寄存器的功能码

        std::cout << "读取的数据: " << read_value << std::endl;

    }
    catch (const std::exception& e) {
        std::cerr << "异常: " << e.what() << std::endl;
        return 1;
    }

    return 0;
}