I'm trying to read messages sent form my Arduino over a Serial port using baud rate 9600.
My Arduino code is programmed to send a "1" whenever I press a button and a "0" when I release my finger off the button.
So it's not constantly sending data.
My C# Program is to read that message and add it to a ListBox. But whenever I start it, the program hangs.
private void button1_Click(object sender, EventArgs e)
{
SerialPort port = new SerialPort();
port.BaudRate = 9600;
port.PortName = "COM4";
port.ReadTimeout = 1000;
port.Open();
timer1.Start();
}
private void timer1_Tick(object sender, EventArgs e)
{
try
{
ee = port.ReadLine();
listBox1.Items.Add(ee);
}
catch (Exception)
{
timer1.Stop();
}
}
I guess, maybe the reason is that my program should check if there's data available to be received before receiving?
Try something like this instead. It will at least not hang, and then you can sort out what sort of data your are getting via DataReceived
From there you can determine how to better write your app
private void button1_Click(object sender, EventArgs e)
{
SerialPort port = new SerialPort();
port.BaudRate = 9600;
port.PortName = "COM4";
port.ReadTimeout = 1000;
// Attach a method to be called when there
// is data waiting in the port's buffer
port.DataReceived += new
SerialDataReceivedEventHandler(port_DataReceived);
// Begin communications
port.Open();
}
private void port_DataReceived(object sender,
SerialDataReceivedEventArgs e)
{
// Show all the incoming data in the port's buffer in the output window
Debug.WriteLine("data : " + port.ReadExisting());
}
SerialPort.DataReceived Event
Indicates that data has been received through a port represented by
the SerialPort object.
SerialPort.ReadExisting Method ()
Reads all immediately available bytes, based on the encoding, in both
the stream and the input buffer of the SerialPort object.
To avoid this problem, you need to add "\n" to your data in your arduino because
port.ReadLine(); search for ending line ("\n")
For example, let's say that the data which arduino sends is "1", to read this data with port.ReadLine(); it should be "1\n"
Also, do not worry, port.ReadLine(); doesn't read "\n". Just stops there when it sees "\n".
I hope it helps.
Related
I have a serial port connection to weighing indicator(display) that connecting to the scale.
The device B has 3 state:
No Power(Plug off)
Power On(Plug on but not power up)
Display Ready(after press power up)
On any state, I can connect to serial port but I can only get DataReceived event when display ready state (#3). If on certain timeout no value from DataReceived, I need to trigger the screen to alert the user that device is not on ready state. When user press Power On and after the display is ready, then I can revoke the trigger so the screen can continue when DataReceived arrived.
I have try using ManualResetEvent based from what I found:
ManualResetEvent DataReceivedEvent = new ManualResetEvent(false);
private void Open_Click(object sender, RoutedEventArgs e)
{
// All the port initialization
_serialPort.Open();
TimeSpan waitTime = TimeSpan.FromMilliseconds(5000);
bool noData = DataReceivedEvent.WaitOne(waitTime);
}
private void SerialPortOnDataReceived(object sender, SerialDataReceivedEventArgs serialDataReceivedEventArgs)
{
SerialPort sp = (SerialPort)sender;
DataReceivedEvent.Set();
}
The MRE seems promising since I can wait, Set the event so I know the data is received, and return false when WaitOne not Set but it freezing my UI and it just run one time after serial port is open.
Is it possible to put ManualResetEvent under thread to keep loop and wait without freezing UI? I try to search for it but I cannot find it.
Based from #kunif suggestion, I have come to use DateTime as a benchmark to see if the device and display is disconnected. The connection status return accordingly on device turn off, display power up and display ready.
private DateTime LastBufferTime;
private bool Running { get; set; } = true;
private void Open_Click(object sender, RoutedEventArgs e)
{
Running = true;
LastBufferTime = DateTime.Now;
_serialPort.DataReceived += SerialPortOnDataReceived;
_serialPort.Open();
Task.Run(() => ThreadTimer());
}
private async void ThreadTimer()
{
while (Running)
{
if ((DateTime.Now - LastBufferTime).TotalSeconds > 5)
{
// No response from DataReceived
}
else
{
// Response from DataReceived
}
}
}
private void SerialPortOnDataReceived(object sender, SerialDataReceivedEventArgs serialDataReceivedEventArgs)
{
SerialPort sp = (SerialPort)sender;
LastBufferTime = DateTime.Now;
}
private void Stop_Click(object sender, RoutedEventArgs e)
{
if (_serialPort != null)
{
if (_serialPort.IsOpen)
{
_serialPort.Close();
}
_serialPort.DataReceived -= SerialPortOnDataReceived;
_serialPort.Dispose();
Running = false;
}
}
Code for C#
using System;
using System.Windows.Forms;
using System.IO.Ports;
SerialPort port;
private void btnStart_Click(object sender, EventArgs e)
{
port = new SerialPort("COM6", 9600);
port.Open();
port.Write("START");
port.Close();
}
Code for Arduino
"#"include "MOVIShield.h"
MOVI recognizer(true);
Code inside the loop
signed int res=recognizer.poll();
if(Serial.available() > 0){
String data = Serial.readString();
if(data = "START"){
recognizer.ask("Hello. My name is John");
}
}
I tried to click the btnStart to send "START" to my Arduino Program and the Arduino Program should run ask("Hello. My name is John") after received the data from C# program. But when I clicked the btnStart, there is nothing happened.
You can try different a couple of different things:
1- Make sure COM port parameters are the same on both sides
As explained at http://www.instructables.com/id/How-to-connect-Arduino-to-a-PC-through-the-serial-/
Add this to the Arduino C code outside the loop:
Serial.begin(9600);
And change your C# to a code similar to:
private void btnStart_Click(object sender, EventArgs e)
{
port = new SerialPort("COM6", 9600);
port.DataBits = 8;
port.StopBits = StopBits.One;
port.Handshake = Handshake.None;
port.Parity = Parity.None;
port.Open();
port.Write("START");
port.Close();
}
2- Use a different tool than C# to test if you can communicate to the Arduino.
e.g. this tool has 15 days demo: https://www.eltima.com/rs232-testing-software/
I imagine the single equals in this line may have something to do with it.
if(data = "START")
I am trying to communicate with ECUsim 2000 which is OBD-ll ECU simulator (link). Yet, responses I always receive from device are something like "??" or "?" (when I run programs like TouchScan or OBD Auto Doctor, they successfully reads data so device is working properly). I am sending comand in C# via
serialPort1.Write("010D\r")
and I am receiving signal in SerialPort's DataReceived event as
message = "Data Received: " + serialPort1.ReadExisting();
this.Invoke(new EventHandler(displayText));
I do not now what I am missing. Here is the full source code
private void Form1_Load(object sender, EventArgs e)
{
serialPort1.PortName = "COM3";
serialPort1.BaudRate = 115200;
serialPort1.Parity = System.IO.Ports.Parity.None;
serialPort1.StopBits = System.IO.Ports.StopBits.One;
serialPort1.DataBits = 8;
serialPort1.Handshake = System.IO.Ports.Handshake.None;
serialPort1.Open();
}
private void button1_Click(object sender, EventArgs e)
{
if (serialPort1.IsOpen)
{
serialPort1.Write("010D\r");
}
}
private void displayText(object sender, EventArgs e)
{
textBox1.AppendText(message + "\n");
}
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
message = "Data Received: " + serialPort1.ReadExisting();
this.Invoke(new EventHandler(displayText));
}
Default communication settings of ECUsim 2000 are
Baud Rate: 115200
Data bits: 8
Parity: none
Stop bits:1
protocol is ISO 15765-4 and there are two switches on the device which are protocol attribute CAN ID 29/11 bit and CAN Baud Rate 500 kbps/250kbps. Maybe, the problem are related with these such that there is no proper communication set.
Another question -> Is there a way to set protocol (like ISO 15765-4) in serial communication?
There are two problems related with the code given.
1) There are two connector on the ECUsim 2000. One of them is type B USB port, other one is Diagnostic Link Connector (DLC). If one wants to get connected to device via type B USB port, baud rate is: 115200. If DLC is used, Baud Rate is most probably either 9600 or 38400. Here, connection is made through scan tool, therefore (for my case) baud rate 38400 worked for me.
2) As mentioned in the comment, In order to get data, Read() method of SerialPort must be used. It can be used as the following code:
int buffSize = 1024;
bool cont = true;
int count = 0;
byte[] bff = new byte[buffSize];
string returnVal = string.Empty;
count = serialPort1.Read(bff, 0, buffSize);
returnVal += System.Text.Encoding.Default.GetString(bff, 0, count);
I've coded a little program to read/send SMS messages using a GSM device. My code worked fine on one kind of device. Today I am using a different device and my program can't receive from it (although it can send to it just fine). The device works just fine with the same configs under puTTY.
private void Form1_Load(object sender, EventArgs e)
{
Variables.sp.PortName = "COM1";
Variables.sp.BaudRate = 9600;
Variables.sp.DataBits = 8;
Variables.sp.Parity = Parity.None;
Variables.sp.StopBits = StopBits.One;
Variables.sp.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);
try
{
Variables.sp.Open();
Variables.sp.WriteLine("AT\r");
//Variables.sp.WriteLine("AT+CMGF=1\r");
}
catch
{
MessageBox.Show("Can't open COM1. Quit and try again.");
}
}
private static void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
SerialPort sp = (SerialPort)sender;
string indata = sp.ReadExisting();
MessageBox.Show(indata);
}
Any idea why it would work fine on one device and not the other? While I'm typing the same commands under puTTY and they both work the same?
I'm working on a project that involves my client software sending data to a Arduino microcontroller, AtMega32U4, through serial communication. I've looked through many answered questions so far yet none of them were specific to my problem. However, I believe my problem may be limited to threading issues or Arduino autoreset problems.
Code 1:
public MainForm()
{
InitializeComponent();
serialPort1.DataReceived += new SerialDataReceivedEventHandler(serialPort1_DataReceived);
serialPort1.DtrEnable = true;
//serialPort1.RtsEnable = true;
}
private void button3_Click(object sender, EventArgs e)
{
// Disables button while processing
button3.Enabled = false;
GetDir dir = new App.GetDir();
dir.getCoords(Origin.Text, Destination.Text, Application.StartupPath + #"\temp2.html", "temp2.xml");
dataBrowser.Navigate(Application.StartupPath + #"\temp2.html");
dataBrowser.Update();
waypoints = dir.coordsLat.Length;
counter = dir.coordsLat.Length;
coords = new double[dir.coordsLat.Length, 2];
for (int i = 0; i < counter; i++)
{
coords[i, 0] = (Convert.ToDouble(dir.coordsLat[i]));
coords[i, 1] = (Convert.ToDouble(dir.coordsLon[i]));
}
//serialPort1.Close();
//System.Threading.Thread.Sleep(1000);
if (serialPort1.IsOpen && !doubleClick)
{
serialPort1.Close();
System.Threading.Thread.Sleep(2000);
try
{
serialPort1.Open();
}
catch (Exception exception)
{
MessageBox.Show(exception.Message, "Cannot open serial port");
}
System.Threading.Thread.Sleep(2000);
}
else
{
if (!serialPort1.IsOpen)
{
try
{
serialPort1.Open();
doubleClick = true;
}
catch (Exception exception)
{
MessageBox.Show(exception.Message, "Cannot open serial port");
}
System.Threading.Thread.Sleep(2000);
serialPort1.Write("^");
System.Threading.Thread.Sleep(1000);
Console.WriteLine('^');
//button3.Enabled = true;
}
}
}
private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
//System.Threading.Thread.Sleep(1000);
readData = serialPort1.ReadLine();
Console.WriteLine(readData);
// If microcontroller sends "&", it is ready to receive next piece of data
if (readData == "&")
{
sendRequest = true;
}
else
{
sendRequest = false;
}
// Write next piece of data to microcontroller if it is ready
if (sendRequest)
{
this.BeginInvoke( new EventHandler (write_serialPort1));
}
}
In during the debugging of code 1, the event handler (serialPort1_DataReceived) never gets called. In this process, somehow button3_click gets called twice as the console outputs '^' twice. Afterwards, the client stalls since there is nothing beind received. Keep in mind that the Arduino will respond with an ampersand ('&') once it has received the circumflex ('^'). The Arduino code has been tested on the Arduino IDE and appears to be working fine. I believe the problem with button3_click being called twice comes from the button3_down and button3_up.
However, I was able to bypass this issue with Code 2. But also hit another brick wall.
Code 2 :
private void button3_Click(object sender, EventArgs e)
{
// Disables button while processing
button3.Enabled = false;
GetDir dir = new App.GetDir();
dir.getCoords(Origin.Text, Destination.Text, Application.StartupPath + #"\temp2.html", "temp2.xml");
dataBrowser.Navigate(Application.StartupPath + #"\temp2.html");
dataBrowser.Update();
waypoints = dir.coordsLat.Length;
counter = dir.coordsLat.Length;
coords = new double[dir.coordsLat.Length, 2];
for (int i = 0; i < counter; i++)
{
coords[i, 0] = (Convert.ToDouble(dir.coordsLat[i]));
coords[i, 1] = (Convert.ToDouble(dir.coordsLon[i]));
}
serialPort1.Close();
try
{
serialPort1.Open();
}
catch (Exception exception)
{
MessageBox.Show(exception.Message, "Cannot open serial port");
}
if (serialPort1.IsOpen)
{
System.Threading.Thread.Sleep(2000);
using (serialPort1)
{
serialPort1.Write("^");
System.Threading.Thread.Sleep(1000);
Console.WriteLine("^");
serialPort1.Close();
System.Threading.Thread.Sleep(5000);
}
}
else
{
button3.Enabled = true;
}
}
private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
//SerialPort sp = (SerialPort)sender;
System.Threading.Thread.Sleep(10000);
/*if (!serialPort1.IsOpen)
{
serialPort1.Close();
System.Threading.Thread.Sleep(10000);
serialPort1.Open();
System.Threading.Thread.Sleep(10000);
}*/
//serialPort1.Open();
//using (sp)
using (serialPort1)
{
serialPort1.Open();
System.Threading.Thread.Sleep(5000);
readData = serialPort1.ReadExisting();
Console.WriteLine(readData);
// If microcontroller sends "&", it is ready to receive next piece of data
if (readData == "&")
{
sendRequest = true;
}
else
{
sendRequest = false;
}
// Write next piece of data to microcontroller if it is ready
if (sendRequest)
{
this.BeginInvoke(new EventHandler(write_serialPort1));
}
}
}
In Code 2, the event handler does get called and the button3_click only runs once. But when it tries to open the port, it returns the error 'Access to Port X denied'. Furthermore, I wish I didn't have to close and open the ports like this, but when the event handler is called (in an earlier code) it returned the error that the COM Port was not opened. In order to satisfy that error, I had to close it and reopen it during button3_click and event handling.
I've added a lot of delay in the code after I read about many problems dealing with the threading issues with serial communication. I had even tried a minute delay in hopes of a thread ending to solve the problem. However, no luck there.
I also specified my serial port in the MainForm designer instead of declaring it in the code (At first I did both and realized it was redundant). I'm not sure if this contributes to the problem, but I've seen examples of both being used.
Lastly, it could definitely deal with the Arduino auto resetting everytime a serial connection has been made (eg. opening and closing a port). In summary, it seems be sending data through serial, but unable to read the incoming data from serial.
Thank you for reading this and if someone could point me in the right direction, it would be very much appreciated.
Edit #1: Even after using BeginInvoke in Code 1, it still deadlocks because the event handler was never called.
Edit #2: Edits to Code 1 as per newbie's suggestions.
Edit #3: Added mainform initialization and updated Code 1 to current state.
Edit #4: Deleted (Commented out) the sleep at the event handler. I was sleeping during the event handler, thus I couldn't receive anything that the microcontroller would send to me. Code works fine as expected now.
Make sure you are using COM1, if you do not COM1 serial port,
change through Computer -> Device Manager -> Ports (COM & LPT) ->
Select the COM to be changed -> Port Settings -> Advanced -> ComPort Number -> select COM1.
Make sure that you have installed jumper / connect with a screwdriver
between pin2 and pin3 of COM1.
Add button1 and textBox1 to Form and run this program
using System;
using System.Windows.Forms;
using System.IO.Ports;
using System.Threading;
using System.Text;
namespace WindowsFormsApplication1 {
public partial class Form1 : Form {
const int MAX_BUFFER = 100;
int i = 0;
byte[] DataReceived = new byte[MAX_BUFFER];
SerialPort serialPort = new SerialPort();
public Form1() {
InitializeComponent();
serialPort.DataReceived += new SerialDataReceivedEventHandler(serialPort_DataReceived);
}
void serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e) {
// wait data ready
Thread.Sleep(500);
// while data ready in buffer
while (serialPort.IsOpen && serialPort.BytesToRead > 0) {
// read data serial
DataReceived[i] = Convert.ToByte(serialPort.ReadByte());
// counter data
i++;
// reset conter if more then maxvalue
if (i >= MAX_BUFFER) {
i = 0;
}
}
if (i == 1 && DataReceived[0] == ASCIIEncoding.ASCII.GetBytes("^")[0]) {
this.textBox1.Invoke(new Action(() => {
this.textBox1.Text = ASCIIEncoding.ASCII.GetString(DataReceived, 0, 1);
}));
}
}
public void InitSerialPort() {
serialPort.PortName = "COM1";
serialPort.BaudRate = 9600;
serialPort.Parity = Parity.None;
serialPort.DataBits = 8;
serialPort.StopBits = StopBits.One;
serialPort.ReceivedBytesThreshold = 1;
}
private void Form1_Load(object sender, EventArgs e) {
// initialize serial port
InitSerialPort();
// assure port is closed before open it
if (serialPort != null && serialPort.IsOpen) {
serialPort.Close();
}
serialPort.Open();
}
private void button1_Click(object sender, EventArgs e) {
if (serialPort.IsOpen) {
serialPort.Write("^");
// wait data sent
Thread.Sleep(500);
}
}
}
}
In accordance to my 4th edit, deleted (Commented out) the sleep at the event handler. I was sleeping during the event handler, thus I couldn't receive anything that the microcontroller would send to me. Code works fine as expected now. Nothing was wrong with the serial ports on either components.