功能需求：
PC机作为上位机，通过串口发送控制指令 F(ading) or B(link) 给Arduino，根据不同指令来实现LED闪烁或者渐明渐暗。
实现方式：
单片机选用Arduino MEGA 1280，PWM10脚作为输出口，接220欧限流电阻至高亮LED，再与GND脚共地。
上位机用C#作为编程语言，IDE选择VS2010，.Net版本选择了4.0，不过应该能够兼容其它版本的.net framework。之前上位机跟单片机通信时，传递的是字符串，方法是先将PWM值视为ASCII码，转换成对应的Char，然后将Char再转换成String类型。由于ANSI ASCII码表只支持128个字符，所以128-255之间的数在传递的时候就遇到难题，通过串口监视发现，超过127的ASCII发给arduino之后，都被修改为63，导致传输失效。
现在的方法改为直接传递byte类型的无符号数，解决了这个问题。
运行界面如下：
上位机源代码：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO.Ports;
using System.Threading;
namespace WindowsFormsApplication1
{
public partial class frmMain : Form
{
int FlashTimes;
int FlashCounts;
Label FlashingLED;
string TextRead;
public frmMain()
{
InitializeComponent();
}
private int FillSerialPorts()
{
int PortCount;
PortCount = 0;
//加载串口列表
SerialPort _tempPort;
String[] Portname = SerialPort.GetPortNames();
foreach (string str in Portname)
{
try
{
_tempPort = new SerialPort(str);
_tempPort.Open();
if (_tempPort.IsOpen)
{
cboCOMPorts.Items.Add(str);
_tempPort.Close();
PortCount++;
}
}
catch (Exception ex)
{
tsMessage.Text = ex.ToString();
}
}
if (!(PortCount ==0))
cboCOMPorts.SelectedIndex =0;
tsCOMPort.Text = cboCOMPorts.Text;
return PortCount;
}
private void trkPWM_ValueChanged(object sender, EventArgs e)
{
lblPWM.Text = trkPWM.Value.ToString ();
}
private void button1_Click(object sender, EventArgs e)
{
txtRead.Clear();
if (cboCOMPorts.Text == "")
{
tsMessage.Text = "尚未选择串口！";
}
else
{
if (!serialPort1.IsOpen)
{
serialPort1.PortName = cboCOMPorts.Text;
serialPort1.Open();
try
{
tsCOMPort.Text = cboCOMPorts.Text;
tsCOMState.Text = "开启";
}
catch (Exception ex)
{
tsMessage.Text = ex.ToString(); // "串口打开过程中遇到错误，串口不存在或者已经被占用！";
tsCOMPort.Text = "";
tsCOMState.Text = "已断开";
}
}
if (serialPort1.IsOpen)
{
if (rbFading.Checked)
{
serialPort1.Write("F");
byte[] bytesToSend = new byte[1] ;
bytesToSend[0] =Convert.ToByte ( trkPWM.Value *2.55 ); //疑问：当Value=100，ToByte=255，但是((int)(trkPWM.Value * 2.55)).ToString()却是254？
serialPort1.Write(bytesToSend, 0, 1);
//serialPort1.Write( ((Char ) ((int) trkPWM.Value *2.55 )).ToString () ); //这个方法不能传递高于127的数
//tsMessage.Text = ((int)(trkPWM.Value * 2.55)).ToString();
}
else
{
serialPort1.Write("B");
serialPort1.Write(Convert.ToChar(Convert.ToInt16(trkPWM.Value)).ToString());
}
FlashLED(lblRX, 10);
}
}
}
private void Form1_Load(object sender, EventArgs e)
{
FillSerialPorts();
trkPWM.Value = 80;
}
private void FlashLED(Label LED, int Count)
{
FlashingLED = LED;
FlashCounts = Count;
timer1.Enabled = true;
}
private void DisplayText(object sender, EventArgs e)
{
txtRead.AppendText(TextRead);
}
private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
if (chkReceive.Checked)
{
TextRead = serialPort1.ReadExisting();
this.Invoke(new EventHandler(DisplayText));
FlashLED(lblRX, 10);
}
}
private void timer1_Tick(object sender, EventArgs e)
{
//add flash times
if (FlashTimes <= FlashCounts)
{
FlashingLED.Visible = !FlashingLED.Visible;
FlashTimes++;
}
else
{
timer1.Enabled = false;
FlashCounts = 0;
FlashTimes = 0;
FlashingLED.Visible = true;
}
}
private void frmMain_Activated(object sender, EventArgs e)
{
if (cboCOMPorts.Items.Count ==0 )
FillSerialPorts ();
}
private void button2_Click(object sender, EventArgs e)
{
serialPort1.Close();
timer1.Enabled = false;
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
pictureBox1.Invalidate();
int yOffset=100;
int yBase = 40;
int xOffset = 40;
int i ;
int x=0;
Pen p = new Pen(Color.Yellow ,1);
Graphics g = e.Graphics;
if (trkPWM.Value ==100)
g.DrawLine(p, pictureBox1.Left , pictureBox1.Height - yOffset , pictureBox1.Left + 10 , pictureBox1.Height - yOffset ); // __
else
g.DrawLine(p, pictureBox1.Left , pictureBox1.Height - yBase, pictureBox1.Left + 10 , pictureBox1.Height - yBase); // __
for (i = 0; i <= 5; i++)
{
x = 100 * i;
if (!((trkPWM.Value ==0 )||(trkPWM.Value ==100)))
g.DrawLine(p, pictureBox1.Left + 10 + x, pictureBox1.Height - yBase, pictureBox1.Left + 10 + x, pictureBox1.Height - yOffset); // |
//p.Color = Color.Blue ;
xOffset = trkPWM.Value;
g.DrawLine(p, pictureBox1.Left + 10 + x, pictureBox1.Height - yOffset, pictureBox1.Left + 10 + xOffset + x, pictureBox1.Height - yOffset);//--
if (!((trkPWM.Value == 0) || (trkPWM.Value == 100)))
g.DrawLine(p, pictureBox1.Left + 10 + xOffset + x, pictureBox1.Height - yOffset, pictureBox1.Left + 10 + xOffset + x, pictureBox1.Height - yBase);//|
g.DrawLine(p,pictureBox1.Left + 10 + xOffset + x, pictureBox1.Height - yBase, pictureBox1.Left + 10 + xOffset + x + 100 -trkPWM.Value , pictureBox1.Height - yBase);//__
e.Graphics.DrawString(trkPWM.Value.ToString () + "%", panel1.Font , new SolidBrush(Color.White ), panel1.Left + 120 , 5, StringFormat.GenericDefault);
}
}
private void frmMain_FormClosing(object sender, FormClosingEventArgs e)
{
if (serialPort1.IsOpen)
serialPort1.Close();
}
private void 清空ToolStripMenuItem1_Click(object sender, EventArgs e)
{
txtRead.Clear();
}
}
}
Arduino程序源代码：
//COPYRIGHT DECLARATION
//THIS APPLICATION IS A DEMOSTRATION APPLICATON FOR EDUCATION PURPOSE ONLY. YOU CAN USE OR
//REDISTRIBUTE IT FREELY ON CONDITION THAT YOU WOULD NOT MAKE MONEY OF IT.
//THE DESKTOP APPLICATON WHICH IS PROGRAMMED IN C# WOULD SEND CONTROL CODE AND PARAMETERS, IF ANY,
//TO THE ARDUINO, THE MICROCONTROLLER WOULD MAKE THE LED FADING OR BLINKING IN ACCORDANCE
//WITH THE CONTROL CODE, THEN.
//SINCE THIS IS MY FIRST APPLICATION IN EITHER C# AND ARDUINO, THERE MIGHT BE SOME BUGS IN IT,
//IF YOU RUN INTO ANY EXCEPTIONS, PLEASE REPORT THEM TO ME AT JZOPEN@YEAH.NET.
//HISTORY
//VER 0.101 1:32 2011-7-31
//Add Fade function to the application
//VER 0.100 16:45 2011-7-30
//Add blink function to the application
char CMD; //command
int pwmValue; //PWM value
int PinOUT=10; //output pin
int Interval = 10;
void setup()
{
Serial.begin(9600);
pinMode(PinOUT, OUTPUT); //set the pin 10 as output pin�
CMD = 'F';
pwmValue = 50;
}
void loop()
{
if (Serial.available())
{
char PrevCMD;
PrevCMD = CMD;
CMD = Serial.read();
switch(CMD)
{
case 'B': //Blink
//read PWM value in readPWMValue routine
pwmValue = readPWMValue();
break ;
//any other CASE statement�
case 'F': //Fading
pwmValue = readPWMValue();
break;
default :
CMD = PrevCMD; //当没有按键或者控制指令无效时，继续执行原来的指令
break;
}
}
//if there is no chars income, then execute the last command
switch(CMD)
{
case 'B':
setPWM(pwmValue);
break;
case 'F':
ledFading(pwmValue);
break;
default:
break;
}
}
int readPWMValue()
{
int Value;
while (!Serial.available())
{
//wait for another incoming char�
}
Value=Serial.read();
Serial.print("Parameters received: ");
Serial.println(Value);
return Value;
}
void setPWM(int Value)
{
int i;
Serial.println(Value);
for (i=0; i<=100; i++)
{
//debug
Serial.print(i);
Serial.print(" / ");
if (i<= Value)
{
digitalWrite(PinOUT,HIGH);
//Debug
Serial.println("HIGH");
}
else
{
digitalWrite(PinOUT,LOW);
//DEBUG
Serial.println("LOW");
}
delay(Interval);
}
}
void ledFading(int Value)
{
Serial.print("Fading Value: ");
Serial.println(Value);
int i;
/*
if (Value>=255)
Value = 255;
else
if (Value<=0);
Value =0;
*/
//fade in
for (i=0; i<=Value; i++)
{
analogWrite(PinOUT, i);
Serial.println(i);
delay(Interval);
}
delay(500);
//fade out
for (i=Value; i>=0; i--)
{
analogWrite(PinOUT,i);
Serial.println(i);
delay(Interval);
}
delay(500);
}
当然上面的代码只是为了演示和学习需要，所以会很不完善甚至有错误的地方。
