"Mike" <nomtrxspam@comcast.net> wrote in message
news:ghbhm2hbj3d3l416b1l6veur33s7rb68pr@4ax.com...
> Hello All,
> Please, if anyone can point me to the problem, I'd sure appreciate it!
> I am very new to VB programming and not a programmer to begin with.
> This is part of a Visual Basic 2005 Express Edition program to control a
remote basketball
> scoreboard display unit.
>
> All I'm trying to do is add 5 byte variables and store the result in an
integer
> variable. I added a Try/Catch block to take look at things.
> This exception occurs only when the clock runs down to 00:00 and when one
of either
> SndT1 or SndT2 are some non zero value. The value of 15 for SndMin is due

> 2005\Projects\ScoreBoard1\ScoreBoard\Form1.vb:line 552
>
>
> These are are variable declarations involved
>
> Public Class Form1
>
>     Inherits System.Windows.Forms.Form
>
>
>     Dim SndMin, SndSec, SndT1, SndT2, SndPer As Byte
>     Dim SndT1f, SndT2f, SndHrn, SndCkSum As Byte
>     Dim CkSum as Integer
>     Dim PacketData() As Byte = {&H55, &HCC, 0, 0, 0, 0, 0, 0, 0, 0, 0}
>
>     Public ClockMode As Byte = 0
>     Public Period As Byte = 1
>     Public HornTime As Byte = 2
>     Public T1score As Byte = 0
>     Public T2score As Byte = 0
>     Public T1Fouls As Byte = 0
>     Public T2Fouls As Byte = 0
>     Public Mins As Byte = 0
>     Public Secs As Byte = 0
>
>
> This is the sub in which the overflow exception occurs
>
>     'This routine builds a data packet to send to the remote display
assembly
>
>     Private Sub SendPacket()
>         SndT1 = T1score : SndT2 = T2score : SndPer = Period : SndHrn =
HornTime
>         SndMin = Mins : SndSec = Secs : SndT1f = T1Fouls : SndT2f =
T2Fouls
>         If ClockMode = 1 Then    ' See if a timeout has been called
>             SndPer = CByte(SndPer Or &H80) ' Turn on the flash LED flag
bit
>         End If
>         Try
>             If ExtDisp = True Then  ' Prepare a packet if using an
extended display
>
>                 'Calculate a simple checksum to add to the end of the
packet
>
> The following line will also cause an exception if I change ExtDisp to
True.
>
>                 SndCkSum = CByte(SndMin + SndSec + SndT1 + SndT2 + SndPer
+ SndT1f + SndT2f)
>
>                 ' Load the 7 data bytes and the checksum byte into the

>             "   ex = " + ex.ToString + "   "
>             TextBox3.Text = Str
>             Timer1.Stop()
>         End Try
>     End Sub
>
>
>
>
> "The scientist is possessed by the sense of universal
> causation...His religious feeling takes the form of
> rapturous amazement at the harmony of natural law,
> which reveals the intelligence of such superiority
> that, compared with it, systematic thinking and acting
> of human beings is an utterly insignificant reflection."
> Albert Einstein (theoretical physicist)

"Mike" <nomtrxspam@comcast.net> wrote in message
news:i2sim2llal8qgpdm67fe1372qvd82ilqn0@4ax.com...
>
> Hello Mike and Stephany,
>
> Thanks for the help! I got it working.
> Mike, Unfortunately your solution did exactly the same thing as my
> original code,
> but from your comments I understand now that CByte(x) will overflow if x >
> 255.
>
> Stephany, Your comment reguarding the interim result of the addition being
>  > 255 was the
> other half of the solution.
>
> To test the overflow from the interim results I added the the following 2
> lines of code
> to the main form load sub and sure enough, it throws an exception pointing
> to the 2nd
> line below.
>
> SndMin = 15 : SndSec = 59 : SndT1 = 99 : SndT2 = 99 : SndPer = 130
> CkSum = SndMin + SndSec + SndT1 + SndT2 + SndPer
>
> I don't know the accepted way to do such an addition, but out of
> curiousity
> I tried the following which worked fine, no exception during form loading.
>
> SndMin = 15 : SndSec = 59 : SndT1 = 99 : SndT2 = 99 : SndPer = 130
> CkSum = 0
> CkSum = CkSum + SndMin + SndSec + SndT1 + SndT2 + SndPer
>
> So evidently the interim result can go  as high as the largest size
> variable
> used to the right of the equal sign. That's different from the older
> languages
> that I have experience with. They all handled interim results without
> having
> to deal with it.
>
> The next thing I tried was to use the following 2 lines in the SendPacket
> sub
> and it works just fine.
>
> CkSum = SndMin
> SndCkSum = CByte((CkSum + SndSec + SndT1 + SndT2 + SndPer) And &HFF)
>
> Lastly I tried Stephanys code as follows and it works also and now I
> understand why.
>
> CkSum = SndMin
> CkSum += SndSec
> CkSum += SndT1
> CkSum += SndT2
> CkSum += SndPer
> SndCkSum = CByte(CkSum And &HFF)
>
> Thanks again for the help. Now I can move on and start building the cabnet
> for the
> remote display assembly.
>
> Mike
>
>
>
>
>
> "The scientist is possessed by the sense of universal
> causation...His religious feeling takes the form of
> rapturous amazement at the harmony of natural law,
> which reveals the intelligence of such superiority
> that, compared with it, systematic thinking and acting
> of human beings is an utterly insignificant reflection."
> Albert Einstein (theoretical physicist)

"Mike" <nomtrxspam@comcast.net> wrote in message
news:ghbhm2hbj3d3l416b1l6veur33s7rb68pr@4ax.com...
> Hello All,
> Please, if anyone can point me to the problem, I'd sure appreciate it!
> I am very new to VB programming and not a programmer to begin with.
> This is part of a Visual Basic 2005 Express Edition program to control a
> remote basketball
> scoreboard display unit.
>
> All I'm trying to do is add 5 byte variables and store the result in an
> integer
> variable. I added a Try/Catch block to take look at things.
> This exception occurs only when the clock runs down to 00:00 and when one
> of either
> SndT1 or SndT2 are some non zero value. The value of 15 for SndMin is due
> to the program
> automatically starting a halftime clock that starts at 15:00.
>
> CkSum = SndMin + SndSec + SndT1 + SndT2 + SndPer      <--- The offending
> line of code
> CkSum =  15    +   0    +  99   +   99  +  130 = 343  <-- Values are from
> the texbox in the catch block
> The catch block shows CkSum = 200, but 200 is just the value left from the
> last addition that worked.
>
>
> The variable declrations and the entire sub where the exception is
> originating were pasted
> below from the program code.
>
> TIA
> Mike
>
> This is the output displayed in the textbox by the catch block.
>
> CkSum = 200   SndT1f = 9   HornTime = 1   SndT2f = 9   SndPer = 130
> SndT1 = 99   SndT2 = 99   SndMin = 15
> SndSec = 0   ex = System.OverflowException: Arithmetic operation resulted
> in an overflow.
>   at ScoreBoard.Form1.SendPacket() in C:\Documents and
> Settings\Administrator\My Documents\Visual Studio
> 2005\Projects\ScoreBoard1\ScoreBoard\Form1.vb:line 552
>
>
> These are are variable declarations involved
>
> Public Class Form1
>
>    Inherits System.Windows.Forms.Form
>
>
>    Dim SndMin, SndSec, SndT1, SndT2, SndPer As Byte
>    Dim SndT1f, SndT2f, SndHrn, SndCkSum As Byte
>    Dim CkSum as Integer
>    Dim PacketData() As Byte = {&H55, &HCC, 0, 0, 0, 0, 0, 0, 0, 0, 0}
>
>    Public ClockMode As Byte = 0
>    Public Period As Byte = 1
>    Public HornTime As Byte = 2
>    Public T1score As Byte = 0
>    Public T2score As Byte = 0
>    Public T1Fouls As Byte = 0
>    Public T2Fouls As Byte = 0
>    Public Mins As Byte = 0
>    Public Secs As Byte = 0
>
>
> This is the sub in which the overflow exception occurs
>
>    'This routine builds a data packet to send to the remote display
> assembly
>
>    Private Sub SendPacket()
>        SndT1 = T1score : SndT2 = T2score : SndPer = Period : SndHrn =
> HornTime
>        SndMin = Mins : SndSec = Secs : SndT1f = T1Fouls : SndT2f = T2Fouls
>        If ClockMode = 1 Then    ' See if a timeout has been called
>            SndPer = CByte(SndPer Or &H80) ' Turn on the flash LED flag bit
>        End If
>        Try
>            If ExtDisp = True Then  ' Prepare a packet if using an extended
> display
>
>                'Calculate a simple checksum to add to the end of the
> packet
>
> The following line will also cause an exception if I change ExtDisp to
> True.
>
>                SndCkSum = CByte(SndMin + SndSec + SndT1 + SndT2 + SndPer +
> SndT1f + SndT2f)
>
>                ' Load the 7 data bytes and the checksum byte into the data
> packet array
> ' PacketData(0) and PacketData (1) are initialized to &H55 and &Hcc
> ' respectively to form a constant 2 byte header for the packet
>
>                PacketData(2) = SndMin : PacketData(3) = SndSec :
> PacketData(4) = SndT1
>                PacketData(5) = SndT2 : PacketData(6) = SndPer :
> PacketData(7) = SndT1f
>                PacketData(8) = SndT2f : PacketData(9) = SndCkSum
>
>            Else ' Prepare a packet for a standard display
>
>                'Calculate a simple checksum to add to the end of the data
> packet
>
> This is the line causing the error.
> Line 552
> ********-->     CkSum = SndMin + SndSec + SndT1 + SndT2 + SndPer
>
>                SndCkSum = CByte(CkSum)   ' Explicitly convert the checksum
> to a byte
>
>                ' Load the 5 data bytes and the checksum byte into the
> packet array
> ' PacketData(0) and PacketData (1) are initialized to &H55 and &Hcc
> ' respectively to form a constant 2 byte header for the packet
>
>                PacketData(2) = SndMin : PacketData(3) = SndSec :
> PacketData(4) = SndT1
>                PacketData(5) = SndT2 : PacketData(6) = SndPer :
> PacketData(7) = SndCkSum
>            End If
>
>            ' Send the data packet to the display
>
>            Call SendSerialData(PacketData)
>
>            ' Reset the horn on flag if it was set
>
>            If HornTime > &H7F Then HornTime = CByte(HornTime - &H80)
>
>        Catch ex As OverflowException
>            Dim Str As String
>            TextBox3.Visible = True
>            Str = "CkSum = " + CkSum.ToString + "   SndT1f = " +
> SndT1f.ToString + "   " _
>            + "HornTime = " + HornTime.ToString + "   SndT2f = " +
> SndT2f.ToString + "   " _
>            + "SndPer = " + SndPer.ToString + "   " _
>            + "SndT1 = " + SndT1.ToString + "   SndT2 = " + SndT2.ToString
> + "   " _
>            + "SndMin = " + SndMin.ToString + "   SndSec = " +
> SndSec.ToString + _
>            "   ex = " + ex.ToString + "   "
>            TextBox3.Text = Str
>            Timer1.Stop()
>        End Try
>    End Sub
>
>
>
>
> "The scientist is possessed by the sense of universal
> causation...His religious feeling takes the form of
> rapturous amazement at the harmony of natural law,
> which reveals the intelligence of such superiority
> that, compared with it, systematic thinking and acting
> of human beings is an utterly insignificant reflection."
> Albert Einstein (theoretical physicist)