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How to send hex character to serial port with C# form app?

I want to send the hex over the COM port. I have prepared code manually, but its for string sending.
This is how application looks like currently :
I need to read data from textbox and then send in hex format to COM port.
Currently I am handling the button click with the following sending code, however currently it is sending hard coded values, but I need ones taken from text field.
private void btnSendData_Click(object sender, EventArgs e) {
if (serialPort1.IsOpen) {
dataOUT = tBoxDataOut.Text;
if (sendWith == "WriteLine") {
serialPort1.WriteLine(dataOUT);
} else if (sendWith == "Write") {
serialPort1.Write(dataOUT);
}
}
}

You can read about Standard Numeric Format Strings here. Read the section "The Hexadecimal ("X") Format Specifier".
private void btnSendData_Click(object sender, EventArgs e)
{
if (serialPort1.IsOpen)
{
//dataOUT = tBoxDataOut.Text;
int intVal = Int32.Parse(tBoxDataOut.Text);
dataOUT = intVal.ToString("X");
if (sendWith == "WriteLine")
{
serialPort1.WriteLine(dataOUT);
}
else if (sendWith == "Write")
{
serialPort1.Write(dataOUT);
}
}
}
I would like to include a simple, working example. I do not have a COM port, but the com0com virtual driver works fine for this demonstration; you can download it here. I also used Putty to display the ports' received data; you can download it here.
Here's my program:
public class HexConvert
{
SerialPort mySerialPort;
public HexConvert()
{
InitPort();
}
void InitPort()
{
mySerialPort = new SerialPort("COM1");
mySerialPort.BaudRate = 9600;
mySerialPort.Parity = Parity.None;
mySerialPort.StopBits = StopBits.One;
mySerialPort.DataBits = 8;
mySerialPort.Handshake = Handshake.None;
}
public void SendMessage()
{
try
{
string s = "15"; // "F" In Hexadecimal
int x = Int32.Parse(s);
string s2 = x.ToString("X");
if(!mySerialPort.IsOpen)
mySerialPort.Open();
mySerialPort.WriteLine(s2);
mySerialPort.Close();
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
Here's my com0com utility's Configuration (I added the COM1 and COM2 pair; no other actions taken in this emulator):
Here is my Putty Configuration (Note that I used COM1 in the program, and COM2 in Putty):
And, finally, here is the output that my demo app produces:

Putty Default Serial Configuration

When using C# I can only read the last 4 characters of the value in COM2.
Putty reads it correctly
I have no control or information over the source that is putting the value on COM2.
My C# settings resemble the basic settings on Putty configuration screen, but C# offers more settings, so Putty must have some underlying settings not being shown.
I checked the documentation on Putty, I can't find the default settings on serial port.
My code:
using System.IO.Ports;
...
SerialPort mySerialPort = null;
mySerialPort = new SerialPort("COM2");
mySerialPort.BaudRate = 19200;
mySerialPort.Parity = System.IO.Ports.Parity.None;
mySerialPort.StopBits = System.IO.Ports.StopBits.One
mySerialPort.DataBits = 8;
mySerialPort.Handshake = System.IO.Ports.Handshake.None;
mySerialPort.DiscardNull = true;
mySerialPort.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);
mySerialPort.ReadBufferSize = 2147483647;
...
private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
SerialPort sp = (SerialPort)sender;
string value= sp.ReadExisting(); //I onle get the last four characters
}
So I should be obtaining the value "17159160118A" but I onle get "118A", Putty reads the whole string correctly
So given that I have no information about the signal source, my best bet is to use similar configuration as Putty in my code, do you know what configuration this could be? or what am I doing wrong?

So, I deleted all the code and started again with a clean console application, the source was sending the data in two parts, , I was just only reading the second, I just needed to know what was the string terminator, I found out that it was the null terminator character ('\0') so I used that to concatenate my strings, here's my code:
class Program
{
static void Main(string[] args)
{
using (SerialPort sp = new SerialPort("COM2", 19200, Parity.None, 8, StopBits.One))
{
//sp.DiscardNull = true;
sp.Handshake = Handshake.XOnXOff;
sp.ReadBufferSize = 16384;
sp.Open();
sp.DataReceived += sp_DataReceived;
AppDomain.CurrentDomain.ProcessExit += new EventHandler((x, y) =>
{
sp.Close();
});
Console.ReadKey();
}
}
static string myString = string.Empty;
static void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
SerialPort sp = (sender as SerialPort);
if (sp.BytesToRead > 0)
{
myString += sp.ReadExisting().Trim();
if (myString.Last() == '\0')
{
myString = myString.Trim('\0').Trim();
if (!string.IsNullOrWhiteSpace(myString))
{
Console.WriteLine(myString);
}
sp.DiscardInBuffer();
myString = string.Empty;
}
}
}
}
I commented out //sp.DiscardNull = true; as it was removing all the null characters and it worked, so any way thanks for the downvote.

application hangs when closing a listening port

I'm using com0com to create a part of virtual ports comA/comB, typing the input to comA from hyperterminal and listening on comB in a wpf application. When I run the following code (by triggering Connect), the application successfully connects and is able to get the data from comA, but hangs when I do Disconnect.
public void Connect()
{
readPort = new SerialPort("COMB");
readPort.WriteTimeout = 500;
readPort.Handshake = Handshake.None;
readPort.Open();
readThread = new Thread(Read);
readRunning = true;
readThread.Start();
System.Diagnostics.Debug.Print("connected");
}
public void Disconnect()
{
if (!readRunning)
{
readPort.Close();
}
else
{
readRunning = false;
readThread.Join();
readPort.Close();
}
System.Diagnostics.Debug.Print("disconnected");
}
public void Read()
{
while (readRunning)
{
try
{
int readData = 0;
readData = readPort.ReadByte();
System.Diagnostics.Debug.Print("message: " + readData.ToString());
}
catch (TimeoutException)
{
}
}
}
I tried changing the Read function to a write by using
byte[] writeData = { 1, 2, 3 };
readPort.Write(writeData, 0, 3);
instead of port.readbyte, and it starts working perfectly when disconnecting. Does anyone know if there is anything different about readbyte that could have caused the freeze? Or is it possibly related to com0com?

Just checking back, in case anyone runs into the same issue, I found an alternative way overriding SerialPort.DataReceived like this:
public override void OnDataReceived(object sender, SerialDataReceivedEventArgs e)
{
SerialPort sp = (SerialPort)sender;
byte[] buf = new byte[sp.BytesToRead];
sp.Read(buf, 0, buf.Length);
receivedDataDel(buf);
}

C# Serial Communication to Arduino

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.

Windows automate telnet

I would like to run a set of commands that would typically be run in telnet(from c#).
For example I would like to run the following
using System;
using System.Diagnostics;
namespace InteractWithConsoleApp
{
class Program
{
static void Main(string[] args)
{
ProcessStartInfo cmdStartInfo = new ProcessStartInfo();
cmdStartInfo.FileName = #"C:\Windows\System32\cmd.exe";
cmdStartInfo.RedirectStandardOutput = true;
cmdStartInfo.RedirectStandardError = true;
cmdStartInfo.RedirectStandardInput = true;
cmdStartInfo.UseShellExecute = false;
cmdStartInfo.CreateNoWindow = true;
Process cmdProcess = new Process();
cmdProcess.StartInfo = cmdStartInfo;
cmdProcess.ErrorDataReceived += cmd_Error;
cmdProcess.OutputDataReceived += cmd_DataReceived;
cmdProcess.EnableRaisingEvents = true;
cmdProcess.Start();
cmdProcess.BeginOutputReadLine();
cmdProcess.BeginErrorReadLine();
cmdProcess.StandardInput.WriteLine("telnet telehack.com");
int milliseconds = 2000;
System.Threading.Thread.Sleep(milliseconds);
cmdProcess.StandardInput.WriteLine("exit");
cmdProcess.StandardInput.WriteLine("exit");
cmdProcess.WaitForExit();
}
static void cmd_DataReceived(object sender, DataReceivedEventArgs e)
{
Console.WriteLine(e.Data);
}
static void cmd_Error(object sender, DataReceivedEventArgs e)
{
Console.WriteLine(e.Data);
}
}
}
and keep telnet open to run subsequent commands. For example for the question above I would like to run and receive the following output, but I don't receive any of the telnet output. It doesn't receive any output. This is related.
telnet telehack.com
> Connected to TELEHACK port 53
It is 2:33 pm on Tuesday, September 1, 2015 in Mountain View, California, USA.
There are 31 local users. There are 24906 hosts on the network.
May the command line live forever.
Command, one of the following:
? ac advent basic cal calc
ching clear clock cowsay date echo
eliza factor figlet finger fnord geoip
help hosts ipaddr joke login md5
morse newuser notes octopus phoon pig
ping primes privacy rain rand rfc
rig roll rot13 sleep starwars traceroute
units uptime usenet users uumap uupath
uuplot weather when zc zork zrun
.calc
calc>2+2
> 4

Based on comments I understand that you can use actual telnet protocol implementation instead of calling to telnet.exe, so
Form1.cs
using MinimalisticTelnet;
using System;
using System.Text.RegularExpressions;
using System.Windows.Forms;
namespace Telnet
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private MinimalisticTelnet.TelnetConnection _tc;
private void Form1_Load(object sender, EventArgs e)
{
_tc = new TelnetConnection("telehack.com", 23);
}
private void timer1_Tick(object sender, EventArgs e)
{
ProcessOutput();
}
private void btnSendCommand_Click(object sender, EventArgs e)
{
if (_tc.IsConnected)
{
_tc.WriteLine(tbCommand.Text.Trim());
tbCommand.Clear();
tbCommand.Focus();
ProcessOutput();
}
}
private void ProcessOutput()
{
if (!_tc.IsConnected)
return;
var s = _tc.Read();
s = Regex.Replace(s, #"\x1b\[([0-9,A-Z]{1,2}(;[0-9]{1,2})?(;[0-9]{3})?)?[m|K]?", "");
tbOutput.AppendText(s);
}
}
}
TelnetInterface.cs
// minimalistic telnet implementation
// conceived by Tom Janssens on 2007/06/06 for codeproject
//
// http://www.corebvba.be
using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
namespace MinimalisticTelnet
{
enum Verbs
{
WILL = 251,
WONT = 252,
DO = 253,
DONT = 254,
IAC = 255
}
enum Options
{
SGA = 3
}
class TelnetConnection
{
TcpClient tcpSocket;
int TimeOutMs = 100;
public TelnetConnection(string Hostname, int Port)
{
tcpSocket = new TcpClient(Hostname, Port);
}
public string Login(string Username, string Password, int LoginTimeOutMs)
{
int oldTimeOutMs = TimeOutMs;
TimeOutMs = LoginTimeOutMs;
string s = Read();
if (!s.TrimEnd().EndsWith(":"))
throw new Exception("Failed to connect : no login prompt");
WriteLine(Username);
s += Read();
if (!s.TrimEnd().EndsWith(":"))
throw new Exception("Failed to connect : no password prompt");
WriteLine(Password);
s += Read();
TimeOutMs = oldTimeOutMs;
return s;
}
public void WriteLine(string cmd)
{
Write(cmd + Environment.NewLine);
}
public void Write(string cmd)
{
if (!tcpSocket.Connected) return;
byte[] buf = System.Text.ASCIIEncoding.ASCII.GetBytes(cmd.Replace("\0xFF", "\0xFF\0xFF"));
tcpSocket.GetStream().Write(buf, 0, buf.Length);
}
public string Read()
{
if (!tcpSocket.Connected) return null;
StringBuilder sb = new StringBuilder();
do
{
ParseTelnet(sb);
System.Threading.Thread.Sleep(TimeOutMs);
} while (tcpSocket.Available > 0);
return sb.ToString();
}
public bool IsConnected
{
get { return tcpSocket.Connected; }
}
void ParseTelnet(StringBuilder sb)
{
while (tcpSocket.Available > 0)
{
int input = tcpSocket.GetStream().ReadByte();
switch (input)
{
case -1:
break;
case (int)Verbs.IAC:
// interpret as command
int inputverb = tcpSocket.GetStream().ReadByte();
if (inputverb == -1) break;
switch (inputverb)
{
case (int)Verbs.IAC:
//literal IAC = 255 escaped, so append char 255 to string
sb.Append(inputverb);
break;
case (int)Verbs.DO:
case (int)Verbs.DONT:
case (int)Verbs.WILL:
case (int)Verbs.WONT:
// reply to all commands with "WONT", unless it is SGA (suppres go ahead)
int inputoption = tcpSocket.GetStream().ReadByte();
if (inputoption == -1) break;
tcpSocket.GetStream().WriteByte((byte)Verbs.IAC);
if (inputoption == (int)Options.SGA)
tcpSocket.GetStream().WriteByte(inputverb == (int)Verbs.DO ? (byte)Verbs.WILL : (byte)Verbs.DO);
else
tcpSocket.GetStream().WriteByte(inputverb == (int)Verbs.DO ? (byte)Verbs.WONT : (byte)Verbs.DONT);
tcpSocket.GetStream().WriteByte((byte)inputoption);
break;
default:
break;
}
break;
default:
sb.Append((char)input);
break;
}
}
}
}
}
This is Windows Forms app with 2 textboxes and 1 button and a timer (interval is 1000ms).
I've used code from CodeProject (linked in original question) with some changes to make it actually work.

Coding this may be hard. However, there are free tools out there for Telnet scripting, see Expect for one. If you have an C# application then perhaps your code could generate the Expect script and then run Expect?

Sending the information to telnet seems like it should be straightforward; use SendKeys(). The question becomes how to capture the output.
I found this YouTube video that should help: https://www.youtube.com/watch?v=BDTCviA-5M8
The solution in the video doesn't really address keeping the session open. I'm a bit outside my knowledge area here, but I believe you can start telnet in a worker thread, send commands to it with SendKeys(), capture the output as described in the video, then parse it.
Does that sufficiently resolve the requirement?