Post by thread:[EE]: vb6 solution to share

Since I promised a couple folks that contacted me off list that I would share the working result of the vb challenge, here'tis: Dim Value As Single 'form input value - can be 16 bit floating point single Dim HVal As Long 'hi byte -doesn't need to be long, int works. Long is just a habit Dim LVal As Long 'low byte -doesn't need to be long either, int works. Still a habit HVal = Value/ 256 LVal = Value Mod 256 If LVal > 127 Then HVal = HVal - 1 Then, go send HVal & LVal bytes out via MSComm. This splits the 16 bit value into two bytes that you can send to a PIC serially. Then just reconstruct the word by doing HVal * 256 & summing with the LVal byte. Voila - a simple way to get a 16 bit value out of vb & into a PIC. Jen was a big help in making it so simple.... Chris -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> -----Original Message----- > From: Chris Loiacono [SMTP:spam_OUTchrisTakeThisOuTMAIL2ASI.COM] > Sent: Tuesday, February 18, 2003 9:17 PM > To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU > Subject: [EE]: vb6 solution to share > > Since I promised a couple folks that contacted me off list that I would > share the working result of the vb challenge, here'tis: > > Dim Value As Single 'form input value - can be 16 bit floating point > single > A VB 'Single' is a 32 bit floating point. {Quote hidden}> Dim HVal As Long 'hi byte -doesn't need to be long, int > works. Long is just > a habit > Dim LVal As Long 'low byte -doesn't need to be long either, > int works. > Still a habit > > > HVal = Value/ 256 > LVal = Value Mod 256 > If LVal > 127 Then > HVal = HVal - 1 > > Then, go send HVal & LVal bytes out via MSComm. > HVal and LVal are not bytes though, I presume you are just sending the LSB of each? > This splits the 16 bit value into two bytes that you can send to a PIC > serially. > Then just reconstruct the word by doing HVal * 256 & summing with the LVal > byte. > Voila - a simple way to get a 16 bit value out of vb & into a PIC. > Jen was a big help in making it so simple.... > Chris > Note that this solution rounds any fractional parts of 'Value' to the nearest integer rather than truncating them. Regards Mike -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

A good point to mention, sorry I neglected to do so. Actually, it rounds the intermediate result then shifts it into place to make the low bit. This was intended to take a distance of desired travel in decimal inches - input thru a text box and converted to the number of motor steps. In my app, I multiply the distance by a number = the number of steps per inch in a linear motion system, which can be a 16 bit integer. This passes the high & low bytes out (via MSCOMM) to be summed in the PIC code on the receiving end. The result is always the closest step position. It rounds to the closest step. With a 200 step motor and an 18 thread lead, this gets position within .00028 inches every time... c > Note that this solution rounds any fractional parts of 'Value' to the > nearest integer rather than truncating them. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam.....mitvma.mit.edu with SET PICList DIGEST in the body

Chris Loiacono wrote: > This was intended to take a distance of desired travel in > decimal inches - input thru a text box and converted to > the number of motor steps. In my app, I multiply the > distance by a number = the number of steps per inch in > a linear motion system, which can be a 16 bit integer. > This passes the high & low bytes out (via MSCOMM) to > be summed in the PIC code on the receiving end. Have not red previous posts of this thread, sorry. How about going this way: - two text boxes: left box for two digits at the left of a decimal delimiter; right box for two digits at the right of it. (Label box with a decimal delimiter is placed between them). - when either text box gets a focus ("GotFocus" event) then its content should be selected: Private Sub Text1_GotFocus() Text1.SelStart = 0 Text1.SelLength = Len(Text1.Text) End Sub - changing the content of Text1 box we fire sub Text1_Change(): Private Sub Text1_Change() If Len(Text1) = 2 Then Byte1 = (Asc(Left(Text1, 1)) - 48) * 16 + Asc(Right(Text1, 1)) - 48 End If End Sub Byte1 is a byte to hold two decimal digits at the left of a delimiter; (Don't forget to declare it: Dim Byte1 As Byte) Left(Text1, 1) is left char of Text1 textbox; Asc(Left(Text1, 1)) is ASC code of the char: 48 for "0" , 57 for "9"; Thus (Asc(Left(Text1, 1)) - 48) gives 0 for "0" , 9 for "9"; (Asc(Left(Text1, 1)) - 48) * 16 converts left char of Text1 into 4 most significant bits of byte variable Byte1. Asc(Right(Text1, 1)) - 48 converts right char of Text1 into 4 least significant bits of byte variable Byte1. Get Byte2 in a similar way from Text2 textbox. Send them to PIC. Nobody needs to be 100% Scott Dattalo (1 ScDat) to get a PIC convert two bytes holding 4 decimal digits into something appropriate. (0.1% ScDat is pretty enough, I think :-) Mike. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservspam_OUTTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body