I need to be able to write signed bytes to a serial port using SerialPort.Write() method, except that method only takes byte[] arrays of unsigned bytes, how would i write a signed byte to the serial port?For what I'm working on the particular command takes values from -1700 to 1700.
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How can I write a signed byte (sbyte) to unmanaged memory using VB.NET? I can use Marshal.WriteByte() to write an unsigned byte, but there doesn't appear to be an overload for signed bytes.
View 1 RepliesI would like to know how to convert a unisgned byte to signed byte
Atm I got this
a
Function readSignedByte() As SByte
'-128/127
Dim b As SByte
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it doesn't work one that well works for numbers positive over 127 if lets say ReadByte() has 128 it would give overflow error which I don't want it to give I would like it to overflow the number to negivate value aka its signed value.
I've inherited a tested function that processes incoming data from a .NET Serial Port. (Dim RXBuffer as string = serialport1.ReadExisting) I've written a different part of the application that processes a byte array as received from an asynchronous .NET socket.
Is there a way I can convert the byte array into a string as if it arrived from the serial port?
I would prefer to rewrite a very long 'if statement' into byte array functions syntax that look like:
dim b as boolean = IsBitSet(state_buffer(i), j) 'rather than:
dim b as boolean = (Asc(Mid(RXPacket.Pdu, CInt((i - (i Mod 8)) / 8) + 1, 1)) And CInt(2 ^ (i Mod 8))) > 0
I just need to write data to serial port to control a toy car
Moving left, right, forward, back.
i am trying to write-read data from serial port but it don't work my code look like this
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I have an array of Bytes. Most of these are interpreted as Unsigned. On certain occasions I need to interprete the byte as signed. Why can't Byte convert to SByte? What I'm doing: I'm trying to program a disassembler for an 8-bit video game ROM. My program reads the ROM and processes each instruction. The instructions are interpreted as unsigned. Some arguments for instructions would be treated by two's complement in the original hardware, however, to make a signed number.
View 8 RepliesI need to write an application for receiving data (ascii characters) from microcontroller through the serial port in three separate parts. I've created three RichTextBoxes, but I do not know which commands I need to type. In first textbox I need to receive one byte... next six bytes need to be placed in second text box, and finally last seven bytes need to be placed in third textbox.
View 11 Repliesi am a absolute beginner and i want to use vb to receive data from micro controller through serial port using rs232 standards, i found this code to receive the data serially, can any one tell me where should i paste this code, so that the data received will be displayed in message box.Private Sub DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) HandlesSerialPort1.DataReceived
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The link below has code to connect to a modem thru the serial port but it is for an earlier version of VB. when I convert the code, it does not fully convert and has 4 errors that prevent building the project. can someone tell me what needs to be changed or added?
[URL]
Note: the error: not CLS-Compliant
I need to read signed and unsigned 8 bit, 16 bit and 32 bit values from a file stream which may be little-endian or big-endian (it happens to be a tiff file which carries the byte order indicator at the start).I initially started by writing my own functions to read the values and was able to do so for unsigned values. e.g.
Public Function ReadUInt32() As UInt32
Dim b(4) As Byte
input.Read(b, 0, 4)
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But then I started looking at signed values and my brain broke.As an alternative, I found the IO.BinaryReader which will let me read signed values directly but doesn't seem to have any way to indicate that the data is big-endian or little-endian.Is there a nice way of handling this? Failing that, can someone tell me how to convert multiple bytes into signed values (in both byte orders)?
I have a stand alone VB.Net 2005 application that uses a serial port that generally stays open while the application runs on a Windows XP system. In trying to bullet-proof the UI, I ran into a problem when the USB to Serial Converter normally used to provide the serial port is disconnected while the serial port is open. In trying to handle the resulting error when accessing the port, I find I cannot close the port.
When trying to do so, the error message says something like "unable to close the port. You may not have sufficient permissions." Reconnecting the USB/Serial Converter does not reactivate the port.
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I'm mohammed from Oman ,I'm visual studio.net programmer How I can Read the Data From Barcode Weight scales By Serial port and TcpIp port
View 7 RepliesI have a Windows form.in windows form have a combo box that give me a list of available port serial with it code (Dim ports As String() =SerialPort.GetPortNames())for example( Com1,Com8,Com15,...).but I want to give me fullname of serial port in device manager for example in dvice manager is these (Comunication Port(COM1) - Printer Port(LPT1) And USB Serial Port(COM8)).how to Get it?
View 2 RepliesIf I uninstall the COM1 and reboot, it works. If I shut down (power off) and restart, I get the message below. If I uninstall then click on Scan for Hardware Changes,The given port name does not start with COM/com or does not resolve to a valid serial port. Parameter name:portName
View 8 RepliesIm having problem with the Serial Port. When i run my program, "Access to the port 'COM1' is denied". What does that mean? Im not sure whats happening because theres no error in my code. Someone suggest me to use 'COM2'. Which is also the same result. I have a microcontroller, programmed and run it. And i need to capture the data onto my vb, which is on a multiline textbox. How to i do that?Just to double check my code?
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I previously posted this problem about 4 months ago, there was some dialog but the problem was never resolved.My application involves transferring blocks of data (in the form of bytes) between the PC and an embedded MCU via USB.The system uses an FDTI 232RL chip to interface between MCU and USB using a "Virtual Comm Port" driver (supplied by FDTI).Everything works fine until the application encounters a byte value of h1A (dec 26, Ascii "SUB") when transferring data from the Serial Port input buffer to a byte array. It would appear that the data transfer is aborted when the h1A byte is encountered.Many "fixes" have been tried but none are 100% successful.All data is read and stored in BYTE format. The software should not be interpreting any BYTE as an Ascii control character.I am using Visual Studio 2008 Express. Is it possible that this problem is unique to the (Express) version since only a very small number of people have also encountered this problem?
View 4 RepliesI am trying to buld a DLL in VB.NET 2010 that will be use to control a vending machine.Whin a call into the DLL to a function to open and setup the comport the first time its opens it just fine, but if a call into the DLL again it does not know that the port is open even if it is still open. I can check with another program and is shows the port is open and if I try to call into the DLL again to open the port I get an error that the port is already open. Any idea how to set this up so it will work
View 7 Repliesi'm creating a windows form to send/receive data to/from serial port.At first : i send the data as string to the serial port .Second: i tried to read the string again for test the successfull transmission , but i recieved empty string
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I can find documentation (preferably with code samples) that will guide me through all the steps to activate and read from a serial port?
View 6 RepliesFor my application a need to set a breakstate on/off of 25ms.In Xp this runs fine when I set breakstate=true and wait for 25ms and then breakstate= false and wait 25ms.In CE6.0 when I set breakstate = true, it only throws a puls.It is even not possible to keep breakstate on.
how to solve this or is there an alternative to simulate a breakstate?
can we communicate to Serial port COM1 through Microsoft Robotic Studio?We are developing wireless robot which will take data from serial por
View 14 RepliesFor many years, I have sent data between 2 computers using serial ports."Here is the data", "Thank you for that data!" type stuff.Where do I get more information for doing the same thing with 2 computers that are networked together? Assume a local ethernet connection.I have experimented with serial-ethernet modems and that works well but I don't want any more hardware.Is there a good thread here I should read?I want 2 VB programs running and I want to exchange data periodically.
View 2 RepliesI know things have changed in VB2005.net and i have Express and i want to controll the serial port. I have a program from VB6 that i understand and i tried to convert it but i get alot of errors and i have know idead what they mean. As you can tell i haven't been programming very long.
If someone can point me in the right direction for programming the serial port in VB2005 .net i would appreciate it or tell me what differences there may be.
I am developing a UI for an embedded device that I have designed and built. The device uses an FT232 chip which, when connected via USB is automatically assigned one of the COM ports. I was wondering if there is a way to set up a loop which would automatically detect which COM port the device has been assigned. I could then add some handshaking to verify that the port is correct.
View 4 RepliesI have a little code for get the serial port available in the system.
For Each pn As String In IO.Ports.SerialPort.GetPortNames
Debug.WriteLine("NAME : " + pn.ToString)
Next
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So, The PORT1 and PORT5 its ok (because this are real serial port, with a real RS232 interface), but PORT4, I don't know.
How I can do for get only true serial ports ?
I am facing problem reading data from Serial port. Actually I am connecting with the hardware device called Crimp Force Analyzer. It gives the data on hyperterminal and I have to read that data from my <acronym title="Visual Basic">vb</acronym>.net program. The data is somewhat like this:
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I'm looking for a program that would read and import data from my serial port and then graph it. I don't mind buying it if it's not a free program.
View 6 Repliesi am new to VB.net and i am writeing a program to read a serial port and if there is any thing in the buffer i want to read the data and put it in a string then clear the buffer
View 1 RepliesIve got a big problem.I need to read data from the serial portIve used serialport from the toolbox , but dont know how to use it.I used to do it on a Amiga like this
open serial("serial.device".0.2400.0) rem(open port)
repeat GW.w=readserial(0)
if gw>29 and gw<128
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