產品規格書及封包格式
1.Label1 => 顯示角度數值。
介面：
1.Label1 => 顯示角度數值。
2.Combo_Box => 如果有兩個以上的Comport時可選擇。
3.Button1 => 選擇Comport後連線用。
4.Button2 => 測試CRC時用。
程式碼：
Form1.cs
執行結果：
using System;
using System.Globalization;
using System.IO.Ports;
using System.Windows.Forms;
using static WindowsFormsApp4.CRC;
using Timer = System.Timers.Timer;
namespace WindowsFormsApp4
{
public partial class Form1 : Form
{
private readonly Timer timer;
public Form1()
{
InitializeComponent();
SearchComport();
//設定timer(多久發送一次訊號)
timer = new Timer { AutoReset = true, Interval = 100 };
timer.Elapsed += Timer_Elapsed;
}
//查詢用的封包
private static readonly byte[] data =
{ 0x01, 0x04, 0x00, 0x01, 0x00, 0x01, 0x60, 0x0a };
private readonly SerialPort _serialPort = new SerialPort();
private void Timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
_serialPort.Write(data, 0, data.Length);
}
private void Button1_Click(object sender, EventArgs e)
{
timer.Enabled = true;
}
private void Button2_Click(object sender, EventArgs e)
{
var value = CRC16(data);
Label1.InvokeIfRequired(() => Label1.Text = Convert.ToString(value));
Console.WriteLine($@"value => {value}");
}
private void SearchComport()
{
var ports = SerialPort.GetPortNames();
var count = 0;
if (ports.Length <= 0) return;
foreach (var port in ports)
{
CB_Comport.Items.Add(port);
Console.WriteLine($@"port{++count} => {port}");
}
CB_Comport.SelectedIndex = 0;
}
private void CB_Comport_SelectedIndexChanged(object sender, EventArgs e)
{
//如果之前有開啟就先關閉
if (_serialPort.IsOpen) _serialPort.Close();
//選取到的comport索引
var itemIndex = CB_Comport.SelectedIndex;
//設定comport名稱
_serialPort.PortName = CB_Comport.Items[itemIndex].ToString();
//設定comport鮑率
_serialPort.BaudRate = 9600;
//設定comport讀寫的timeout
_serialPort.ReadTimeout = 500;
_serialPort.WriteTimeout = 500;
//設定接收到data後的動作
_serialPort.DataReceived += ReadData;
//一定要開啟，不然你之前做的都是白工
_serialPort.Open();
}
private void ReadData(object sender, SerialDataReceivedEventArgs e)
{
try
{
var recBuffer = new byte[_serialPort.BytesToRead];
_serialPort.Read(recBuffer, 0, recBuffer.Length);
//不知道為何?!有時回傳會少byte，所以如果不是完整的封包就捨棄
if (recBuffer.Length < 7) return;
Console.WriteLine(BitConverter.ToString(recBuffer));
//封包的第四及五個byte為資料的高位元及低位元
var value = recBuffer[3] << 8 | recBuffer[4];
//Encoder解析度為32768 => 0x8000
var degree = 360f * value / 0x8000;
Label1.InvokeIfRequired(() =>
Label1.Text = degree.ToString("F1", CultureInfo.InvariantCulture));
//以下為測試CRC是否正確
//只取不是CRC的部份，所以只有5個byte
//var buffer = new byte[5];
//for (var i = 0; i < buffer.Length; i++)
//{
// buffer[i] = recBuffer[i];
//}
//var crc = GetCRC(buffer);
//(與0xFF做AND計算，只保留後8個位元)
//var Lo = Convert.ToString(crc & 0xFF, 16);
//(向後位移8位元，如：0x1234 => 0x0012)
//var Hi = Convert.ToString(crc >> 8, 16);
//Console.WriteLine($@"CRC => {Convert.ToString(crc, 16)}");
//Console.WriteLine($@"Hi => {Hi}");
//Console.WriteLine($@"Lo => {Lo}");
//var revHi = Convert.ToString(recBuffer[6], 16);
//var revLo = Convert.ToString(recBuffer[5], 16);
//var revCRC = revHi + revLo;
//var check = revCRC == Hi + Lo;
//Console.WriteLine($@"revCRC => {revCRC} Hi+Lo => {Hi + Lo} Check => {check}");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
public static class Extension
{
//非同步委派更新UI
public static void InvokeIfRequired(this Control control, MethodInvoker action)
{
if (control.InvokeRequired)//在非當前執行緒內 使用委派
control.Invoke(action);
else
action();
}
}
}
在CRC的部份分成兩種方式，一種是計算，一種是查表。
計算的好處是節省空間及明確的表達邏輯，避免複製貼上造成的錯誤。
查表的好處是反應快，節省計算時間。
在這封包格式上CRC佔了2byte = 16bit，所以是使用CRC16的計算方式。
特別要注意CRC計算完後在傳送封包時高低位元要記得交換位置。
C#寫法：
CRC.cs
using System.Collections.Generic;
namespace WindowsFormsApp4
{
internal static class CRC
{
//使用計算的方式
public static ushort CRC16(IEnumerable pDataBytes)
{
ushort crc = 0xffff;
const ushort poly = 0xA001;
foreach (var t in pDataBytes)
{
crc ^= t; //XOR=>兩兩相同為0，不同為1，
//如：1111
// 0001
// _______
// 1110
for (var j = 0; j < 8; j++)
{
//檢查最低位元是否為1
if ((crc & 0x01) == 0x01)
{
crc >>= 1; //向右移一位元，如：0x1234 => 0x0123
crc ^= poly;
}
else
{
crc >>= 1;
}
}
}
return crc;
}
//使用查表的方式
public static ushort GetCRC(IEnumerable values)
{
byte hi = 0xff;
byte lo = 0xff;
foreach (var value in values)
{
var index = lo ^ value;
lo = (byte)(hi ^ aucCRCHi[index]);
hi = aucCRCLo[index];
}
return (ushort)(hi << 8 | lo);
}
private static readonly byte[] aucCRCHi =
{
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40
};
private static readonly byte[] aucCRCLo =
{
0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7,
0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E,
0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9,
0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC,
0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32,
0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D,
0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38,
0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF,
0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1,
0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4,
0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB,
0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA,
0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0,
0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97,
0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E,
0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89,
0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83,
0x41, 0x81, 0x80, 0x40
};
}
}
CRC檢查：
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