How to send a byte to the prop using VB Express 2008 .net

Anubisbot

Hi, i am toying around with VB Express 2008 and the serial port.
I have some communication going, but i have a strange problem.
When i try to send bytes i have to send it as a string or a byte arry is there a way to only send a single byte or do i have to convert the byte to a char.
right now i do that and it sends unicode, but i think i need some else ... since when i send a 1 as a byte it works , when i send 100 it works.
but when i send 250 to 255 and some other numbers i get only a hang up since i think it has to do with the unicode.

So does some one have a idea how to change it to the right acsii format??

VB Code here :

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim associatedChar As Char
        ' Returns "A".
        associatedChar = Chr(1)
        SerialPort1.Write(associatedChar)
        TextBox1.Text = SerialPort1.Readbyte


    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        Dim associatedChar As Char
        ' Returns "A".
        associatedChar = Chr(255)
        SerialPort1.Write(associatedChar)
        TextBox1.Text = SerialPort1.Readbyte
    End Sub

On the other side to it works good from data going in to the pc from 1-255 no problem with the bytes

Post Edited (Anubisbot) : 9/14/2008 5:36:41 PM GMT

Unsoundcode

Hi Anubishot, the Write instruction writes a string of ASCII characters to the serial port but has two overloads (meaning you can use the Write instruction in 3 different ways). To transmit a byte or series of bytes you will need to create an array buffer to hold your data.

This example could be placed inside your button click events,

Dim myarray() As Byte
myarray(0)=255
SerialPort1.Write(myarray,0,1) 'write array index 0 and 1 byte in length

Jeff T.

Anubisbot

Unsoundcode said...
Hi Anubishot, the Write instruction writes a string of ASCII characters to the serial port but has two overloads (meaning you can use the Write instruction in 3 different ways). To transmit a byte or series of bytes you will need to create an array buffer to hold your data.


This example could be placed inside your button click events,



Dim myarray() As Byte

myarray(0)=255

SerialPort1.Write(myarray,0,1) 'write array index 0 and 1 byte in length



Jeff T.

Thanx for the tip, but i have tried that bevore, but i get this nasty error when pushing the button,
Object reference not set to an instance of an object.??


And it says that the variable is used before some value is assigned...

Any idea what that means , i am searching and trying now for 2 days

Unsoundcode

Hi Anubishot, not sure why you·have the errors and don't have the time to check it out right now but heres another way to handle it and it pre assigns·a dummy value(s)

Make·scope of the array cover the class

Public Class Form1

Dim testbyte() As Byte = New Byte(2) {0, 0, 0}

then in the button click event do the following

testbyte(0) = 255

SerialPort1.Write(testbyte, 0, 1)

Jeff T.

Anubisbot

Unsoundcode said...
Hi Anubishot, not sure why you have the errors and don't have the time to check it out right now but heres another way to handle it and it pre assigns a dummy value(s)

Make scope of the array cover the class

Form1

[noparse][[/noparse]color=#0000ff]Dim[noparse][[/noparse]/color][noparse][[/noparse]color=#0000ff]As[noparse][[/noparse]/color][noparse][[/noparse]color=#0000ff]Byte[noparse][[/noparse]/color][noparse][[/noparse]color=#0000ff]New[noparse][[/noparse]/color][noparse][[/noparse]color=#0000ff]Byte[noparse][[/noparse]/color]<FONT size=2>(2) {0, 0, 0}

then in the button click event do the following

testbyte(0) = 255

SerialPort1.Write(testbyte, 0, 1)

Jeff T.

Great, works perfect, u saved me a long night on this.
I have tried the new statement before but could not get the syntax right.

That makes a lot easier.
Now , i know a little more[noparse]:)[/noparse]

Thanx..

Unsoundcode

Good deal,

and of course if the values in the array are constants you can pre define them when you declare the array and save yourself a line of code in each button click.

Jeff T.