Hi Frabs,
What does "slinky" mean? I looked is up and found out it was a spring toy, but I do not really understand what you wanted to say...

Anyway, regarding the reading of bytes from the serial port: I didn't really detail this, because there are literally loads of freely available applications out there which perform the function of serial port sniffing and displaying, in any format you would need.

However, in case someone does want to do this in C#, the serialport class available, which is used in the above example provides several methods. To read bytes, you could use any of the following:

serialPort1.Read(byte_buffer,0,10); //this will read 10 bytes from the serial port and insert them starting with index 0 in a byte array called "byte_buffer", which has to be declared above


received_byte=serialPort1.Readbyte(); //this will read one byte from the serial port, and store it in a variable called received_byte


received_char=serialPort1.Readchar(); //same as above but reads a char


serialPort1.Readline(); //reads characters from the input buffer until the NewLine character is encountered; returns a string

Please pay attention though that the usage of all these functions is somewhat...tricky. In case you call any of these functions and no byte is available in the input buffer of the serial port, your application will appear to hang, and it will do so until either you kill it or the number of expected bytes (or at least one byte, depending on which of the above you use) is finally transmitted by the peripheral connected to the serial port of the PC.

There are ways of making the application work somewhat like in an "interrupt" manner, using the C# concept of "events" which trigger a function when bytes are available in the input buffer of the serial port, but although I am familiar enough to use them, I lack the theoretical notions of C# required to thoroughly explain these.

Regarding your thoughts of giving C# a try... I congratulate you! As you may have noticed, I am no C# expert myself, but for the hardware engineer who sometimes wants to format some text/binary files, to extract some data, to make a simple GUI...or to write some bytes to the serial port, it is a great tool. And this sharpdevelop compiler (not only free, but also open source, which is great!) only asks you to install a small amount on your PC (not hundreds of megabytes, like other IDEs)

Regards,
Cristian

Then you taught me another way to access the serial port, thank you :)

Regards,
Emrah

Enslaving machines to free the mankind...

Hi Cristian,

I am using Visual studio 8, i want to read the data from the serial port, i am actually interfacing pc and microcontroller.the data from the controller is commin to the serial port, from that i need to read and display it on the front end, the GUI is ready but data is to be read. does anyone knw as to how to do this? pls help

Hi Stupido,
Can you give me some example of such devices? What you say is really news to me, although I realize that one of the previous posters in this thread might be experiencing the same.
If you told me what device this is, I might be looking if we have it here and I would investigate what does not work.

Regards,
Cristian

Hi guys,

I try to access my serial port device remotely, pls help.

Ronald

Hi vigz,
To answer short: yes, it is possible. I am a little confuzed though, on your approach. Do you want to use the USB port or thephysical serial port of the PC? If you want to use the serial port, you can surely use the C# example in the article. If you want to use the USB port, you can also use thei c# example, provided that you use a USB-to-serial port converter that comes with Vicrtual Com Port (VCP) drivers. FTDI makes a few of these ICs and they work pretty neat from C#.

Regards,
Cristian

Hi man,
If you follow exactly the steps described in the article, you might want to replace the

//write data to serial port
serialPort1.Write("ABC");

instruction with:

//write data to serial port
serialPort1.Write("ATD 00000");

I believe this should do it. Of course, you can also use your approach, but the easiness of the AT commands resides exactly in giving the user the possibility to use ASCII strings, so you would do it more complicated than necessary.

Good luck,
Cristian

Hi Cristian,

At first i wrote the code for USB-to-RS232 converter cable, like you said the above code work perfectly but now i connect the plain USB cable to the PC and it is not working.

Thanks,

Ruth

Hi Agnezz,
Sorry for the late reply.
My suggestion, is as follows. You may draw the shapes in Paint, under Windows XP. Paint can save in BMP format and you may save your shapes as a known file (for instance "shapes.bmp").
After that you may read that BMP file using a C# program, extract the useful bytes from it, and then flush these bytes via serial port, as indicated in the article. For ease of use, I would suggest to use monochrome bitmap only, because it has the simplest format and you can easily interpret the file in C#, if you are familiar with this programming language.

Regards,
Cristian

I am not really sure what you mean... the communication is half duplex by default, although the PC and the C# are capable of reading/writing bytes simultaneously.

If you are referring to serial protocols with hardware or software shaking then I would only suggest that you google for it in order to find out how exactly to assert/deassert the signals. Fortunately the class described in the article allows for asserting/deasserting the CTS/RTS signals.

Regards,
Cristian

Hi Kimmee,
You can easily write hex data. Try replacing the function for button1 in the above example with:

		void Button1Click(object sender, EventArgs e)
		{
			
			byte [] byte_array=new byte[1];

			serialPort1.PortName="COM1";
			serialPort1.BaudRate=9600;
			serialPort1.DataBits=8;
			serialPort1.Parity=Parity.None;
			serialPort1.StopBits= StopBits.One;

			
			serialPort1.Open();

			//define data to be written to serial port
			byte_array[0]=0x55;
			
			//write data to serial port
			serialPort1.Write(byte_array,0,1);
			
			//close the port
			serialPort1.Close();

		}

Basically, what this does is to define an array of bytes, with just one element. You then define that element to be 0x55 (hence, hex data), and then you instruct your application to send 1 element of byte_array, starting with element with index 0 (this is what serialPort1.Write(byte_array,0,1); does)

Regards,
Cristian

Hi Erwynn,
Have a look at the code below, I will try to explain what it does:

void Button1Click(object sender, EventArgs e)
		{
			byte[] read_buffer=new byte[3];
			//configuring the serial port
			serialPort1.PortName="COM1";
			serialPort1.BaudRate=9600;
			serialPort1.DataBits=8;
			serialPort1.Parity=Parity.None;
			serialPort1.StopBits= StopBits.One;
			
			//opening the serial port
			serialPort1.Open();
			
			//write data to serial port
			serialPort1.Write("ABC");
			
			serialPort1.Read(read_buffer,0,3);
			
			//close the port
			serialPort1.Close();

		}

After sending the "ABC" string to the serial port, this code will listen to the serial port and will write 3 incoming bytes to the read_buffer byte array. The catch with this code is that in case no data will arrive at the serial port from your microcontroller, the C# application will hang and you will have to kill it as a process. In addition, the same behavior will be noticed if your micro sends 2 bytes only, and you instruct your application to wait for 3 incoming bytes. Basically, the application will wait forever until the expected number of bytes will arrive. To be honest, this could be good enough for a school project where you will always know the number of bytes the micro will send back to the PC, so I wish you good luck.

Regards,
Cristian

Hi Jim,
You can easily write hex data. Try replacing the function for button1 in the above example with:

		void Button1Click(object sender, EventArgs e)
		{
			
			byte [] byte_array=new byte[1];

			serialPort1.PortName="COM1";
			serialPort1.BaudRate=9600;
			serialPort1.DataBits=8;
			serialPort1.Parity=Parity.None;
			serialPort1.StopBits= StopBits.One;

			
			serialPort1.Open();

			//define data to be written to serial port
			byte_array[0]=0x55;
			
			//write data to serial port
			serialPort1.Write(byte_array,0,1);
			
			//close the port
			serialPort1.Close();

		}

Basically, what this does is to define an array of bytes, with just one element. You then define that element to be 0x55 (hence, hex data), and then you instruct your application to send 1 element of byte_array, starting with element with index 0 (this is what serialPort1.Write(byte_array,0,1); does)

Regards,
Cristian

Hi ghazanfar,
I would say that in case you know the number of bytes that periodically arrive, you can simply do a "while loop", in which you do the read as described in the article.
In case you do not, I would suggest that you use the BytesToRead property of the SerialPosrt class. This will always return you the number of bytes available in the input buffer. If in your case it returns a 0, then you do not have to do anything. In case it returns something different than 0, then you do know how many bytes you can read from the port, and you can consequently use the Read property of the class, as described in the article.

Regards,
Cristian

Hi Ali,
I would like to point you to an earlier comment on this article, which you may find above:

http://dev.emcelettronica.com/serial-port-communication-c#comment-2437

It describes how you can actually send hexadecimal data to the serial port. You can send your binary data coded in hexadecimal which is fairly easy using the method showed above.

Good luck, and keep us posted with your progress!

Regards,
Cristian

Hi Larbi,
Sorry to get back so late to you with an answer. Fortunately you can do that without much additional hardware excpet for the relay. You should connect the output of the relay to one of the input lines of the serial port (CTS or DSR). The class described in the article provides also the possibility of reading the status of these lines, and returns the answer either as 0 or 1, or as true or false (don't exactly remember, though. t should be easy to map this value to a variable of your choice.
I would recommend you use a pull-down to GND to maks sure the CTS line is seen as a logic "low" when the relay is not active, and you can have the relay pull this line to some 5V.

hi I need power supply without traditional power transformer

kuprugna, Are you trying to read and write data on the same port COM1 with two programs (the one in C# and the hyperterminal) at the same time? I would not do that, I rather would use another one of the serial ports to have one port per program. Then, I would connect both ports with a "null modem", which is made of pure wires, crossed. Take into account the protocol you are using, X-on X-off, or the flow control signals RTS-CTS and DSR. Take into account if your ports have buffers. Remember, you first set both port parameters in agreement with each other, then you write and read bytes. Good luck.

krupagna, you should first be sure your loopback connection is the right one for the control signals you are using, X-on X-off, or CTS-DSR. You will find easily at internet how to connect a proper loopback.

Then, recall you first load the port parameters for the port work as you wish, I mean speed, parities, etc. ¿ Have you set a buffer size for the port? Ok. Once the port parameters are set, send your data. And test you can control the output with a LED.

For the input on the hyperterminal, it is not clear if Windows OS will allow to programs acceding to the same port at the same time, the OS could lock the port for use with one program only, I really do not know what it will do. However, to avoid this possibility, dont you have another port, like COM2, for the hyperterminal program? If so, connect both ports with "null modem", which is only made of wire crossings. Good luck.

i wanna write a program by C# t send file (txt files) to micro and i wanna send them without changing to ASCII codes , it means i want ti send INT and see it in Micro in INT form not AScII codes , ho can i do that?????