Post by thread:[EE] Visual Basic 6.0 Questions

Charles K Roberts II Hello all I use to have a nifty little program to do this but it was on another machine and I lost that PC and didn't make a back up. So I am rehasing the same problem. Here is what I am trying to do. Take a text string from a text box that is a fixed point decimal number between 0-3000 and convert it to a two byte hex number. Then I transmit the two byte hex number via mscomm. I remember doing it this way last time, I put the text in a Varian variable then I made it a two byte hex number. I can't remember how I did this. I remember masking off the upper and lower bytes by XORing them with FF00H and 00FFH. But there was some catch about the data types. Any hints or suggestions, other than make back up copies next time, would be helpful. Chuck

Hi Charles, I don't know how you did it before, and I am not a VB guys, but having worked a lot with VC++ including v6, you can try this: 1. cast the variant as an INT (or copy it's value into an int variable) 2. AND the int with 0xFF, that gives you byte 1 3. shift int number 8 places to the right 4. AND the result of the shift with 0xFF, that gives you byte 2 Good luck. -Mario {Quote hidden}> > > Charles K Roberts II > Hello all > > I use to have a nifty little program to do this but it was on another > machine and I lost that PC and didn't make a back up. So I am rehasing > the same problem. Here is what I am trying to do. > > Take a text string from a text box that is a fixed point decimal number > between 0-3000 and convert it to a two byte hex number. Then I transmit > the two byte hex number via mscomm. > > I remember doing it this way last time, I put the text in a Varian > variable then I made it a two byte hex number. I can't remember how I > did this. > > I remember masking off the upper and lower bytes by XORing them with > FF00H and 00FFH. But there was some catch about the data types. > > Any hints or suggestions, other than make back up copies next time, > would be helpful. > > > Chuck > > -

Use VB's built-in Hex() function, it accepts a number and returns a string representing the hexadecimal value of a number. Example: Create a form with a text box named "Text1" and a label named "Label1". Add a command button to the form and put the following code in the buttons click event. ------------------------------------ Dim strHexVal As String strHexVal = Hex(Val(Text1.Text)) 'Add leading zeros to make it 4 characters long strHexVal = String(4 - Len(strHexVal), "0") & strHexVal Label1.Caption = strHexVal ------------------------------------ Run the program, put a number in the text box, click the button and, the four character hex equivalent appears in the label. Hope this helps, Paul Hutch > {Original Message removed}

On Thu, 03 Mar 2005 11:43:43 -0500, Roberts II, Charles K. <spam_OUTrobertsckTakeThisOuTornl.gov> wrote: > I use to have a nifty little program to do this but it was on another > machine and I lost that PC and didn't make a back up. So I am rehasing > the same problem. Here is what I am trying to do. > > Take a text string from a text box that is a fixed point decimal number > between 0-3000 and convert it to a two byte hex number. Then I transmit > the two byte hex number via mscomm. > > I remember doing it this way last time, I put the text in a Varian > variable then I made it a two byte hex number. I can't remember how I > did this. > > I remember masking off the upper and lower bytes by XORing them with > FF00H and 00FFH. But there was some catch about the data types. Other people have brought up the Hex() that will do the conversion. There are a few issues that you might bump into, though. As I recall these are: 1. A long variable is a signed 8 byte number, which means VB will complain about overflow above 2147483647. The way around this is to OR &h80000000 into the variable if you need to. This shouldn't come up for you with small numbers, but I recently bumped into it in doing mchip float conversions in VB. 2. The internal constants for VB use two byte numbers. This means that if you AND &HFF00 with a number it will be sign extended to &HFFFFFF00, which is not generally what you want. I simply use 65280 as VB will not see this as a negative number. 3. I generally transfer byte arrays to the comm control, which has always worked. Strings might work, but I'm never quite sure when VB is doing a hidden Unicode conversion. I'm not sure that you want to actually convert to hex at any point. If you convert to hex, you'll actually have ascii characters and not the binary representation of the number. If you just wanted to split a number up into high byte, low byte, then you can do that just with math: byteH = (longValue \ 256) And 255 byteL = longValue And 255 The backslash (\) does integer division and dividing by 256 = 2^8 does a right shift of 8 bits. Anding this with 255 = &HFF masks the lower bits. Bradley

After reading other replies and re-reading the original message I'm not sure what is needed. I had thought that a four character string containing the hexadecimal text was desired and, that's what the code in my previous post gives. If what is needed is an integer converted to a two byte string suitable for binary storage/transmission then, the MKI$() function from DOS versions of MS Basic is probably what you want. A VB compatible version of the function is available here: http://www.hutchrick.com/MKI.htm A VB compatible version of the inverse function from DOS Basic, CVI%(), is also available at, http://www.hutchrick.com. Paul Hutch > {Original Message removed}

Robert >From: "Roberts II, Charles K." > > >Take a text string from a text box that is a fixed point decimal number >between 0-3000 and convert it to a two byte hex number. Then I transmit >the two byte hex number via mscomm. 0 to 3000 requires a 12 bit binary number which translates to 3 hexidecimal characters. This means masking the last 4 bits of a two byte binary value. ......AND the 2 bytes with 00FF FFF In order to convert decimal to hex try, somevariable = hex(decimalnumber) In order to convert back, append string in a text box with "&H" hexval = "&H" + textstring Hope this helps Jason In order to > >I remember masking off the upper and lower bytes by XORing them with >FF00H and 00FFH. But there was some catch about the data types. > >Any hints or suggestions, other than make back up copies next time, >would be helpful. > > >Chuck > >