VB 2005 and BS2 -- why won't the signal stop after I close connection?

tbare

Here's a pretty basic question with probably a very easy answer.

I'm using the BoE - USB version

End goal: capture impressions from a press. The press will close a circuit each time there's an impression.

Currently, I'm simulating my press w/ one BS2 with the following code:

' {$STAMP BS2}
' {$PBASIC 2.5}

Flash: 'subroutine labeled Flash

DEBUG "*"
HIGH 1 'turn on
PAUSE 20
LOW 1 'turn off
PAUSE 313 'wait 1/3 second

GOTO Flash 'go back to the rest of the program

and the second BS2 is capturing it that signal like so:

' {$STAMP BS2}
' {$PBASIC 2.5}

btnwrk  VAR Byte
Btn     PIN 0

Main:
BUTTON Btn, 1, 255, 20, btnwrk, 0, No_Press : DEBUG "*" 'send * to output for each impression

No_Press:
GOTO Main 'Start back at the beginning

I've got a simple VB .NET app that i'm using for testing:

Imports System
Imports System.IO.Ports.SerialPort
Imports System.IO.Ports
Imports System.Threading

Public Class Form1
    Delegate Sub SetTextCallback(ByVal [text] As String) 'to change the text of Pause button w/o errors
    Public WithEvents COMPort As New System.IO.Ports.SerialPort
    Public Counter As Integer = 0
    Public PortAvailable As Boolean = False

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim ports As String() = GetPortNames()

        ' Check each available COM port for specified port
        Dim port As String
        For Each port In ports
            If port = "COM5" Then
                COMPort.PortName = "COM5"
                COMPort.BaudRate = 2400
                COMPort.DataBits = 8
                COMPort.Parity = IO.Ports.Parity.None
                COMPort.StopBits = IO.Ports.StopBits.One
                PortAvailable = True
            End If
        Next port
        If PortAvailable Then
        Else
            MsgBox("COM5 not available")
            End
        End If
    End Sub

    Private Sub SerialPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles COMPort.DataReceived
        Counter += 1
        Call updateText(Counter)
        If Counter Mod 200 = 0 Then
            COMPort.Close()
            COMPort.Open()
        End If
    End Sub

    Private Sub updateText(ByVal [Text] As String)
        If Me.lblComOut.InvokeRequired Then
            Dim d As New SetTextCallback(AddressOf updateText)
            Me.Invoke(d, New Object() {[Text]})
        Else
            Me.lblComOut.Text = [Text]
        End If
    End Sub



    Private Sub btnOpen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOpen.Click
        If COMPort.IsOpen = False Then
            COMPort.Open()
        End If
    End Sub

    Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click
        If COMPort.IsOpen = True Then
            COMPort.Close()
        End If
    End Sub
End Class

Currently, when I start the program up, I have to click start to start receiving the signal - perfect.

When I click "Stop," however, the counter in my program stops, but the red light keeps blinking telling me that the BoE is still sending the signal to the app. How do i tell the BS2 to stop running the code OR tell it to stop sending the info to through to the USB port?

Any help would be greatly appreciated - my more complex app is crashing when i hit stop if i keep sending a signal to the computer (impressions are still occurring), even if I 'Close' the connection...

I'm stuck.

TIA!

Mike G

Turn off STAMP 1?

Otherwise send a message to STAMP2 when you click the Stop button. Stamp 2 will need to look for the message and turn off/on accordingly.

tbare

In theory, that would work, but in practice, i can't just "shut off the press" before i click "stop" in my app.

additionally, if i do just "turn off the stamp," when i turn it back on, it goes right back to what it was doing. The only way to get it to stop is to unplug the usb cable, and plug it back in.

what is the code to turn off / on the stamp? that is more or less what i'm looking for.

Unsoundcode

Hi, for serial communications I would say that the SEROUT and SERIN commands are much more flexible than DEBUG. If you want to receive information at the PC from the Stamp and also issue commands to the Stamp, such as stop start etc., you will need to devise some kind of simple protocol. Here is a link to some VB examples. http://forums.parallax.com/showthread.php?96973-VB-Express-to-Stamp-Template

Jeff T.

tbare

Thanks -- it looks like SERIN and SEROUT is what i'm looking for.

As a complete self-proclaimed rookie, and being under a relative time-crunch, how would i do something like the following:

IF SERIN ... [DEC 1]
loop and output for each impression -- probably use similar BUTTON code that i currently have
UNTIL SERIN [DEC 2]

basically, once it receives a 1, look for button presses until it receives a 2, then wait for the next 1...

Any push in the right direction (or flat out code) would be greatly appreciated... they're wanting this thing done as quick as possible (and they asked the new guy whom they knew had no experience with EEPROMs to do it..)

EDIT:
forgot to mention that i've looked at the Nuts & Volts chapter on Serin & Serout dmystified, as well as several other pages, but am running out of time on this.. I am trying to learn, promise!

Mike G

tbare wrote:

what is the code to turn off / on the stamp? that is more or less what i'm looking for.

The help file contains PBasic syntax and code examples. Here's a very simple loop.

' {$STAMP BS2p}
' {$PBASIC 2.5}

result          VAR   Byte

' Initialize to ASCII "0"
result = $30

Main:
  ' Wait 5 seconds for inout from the PC
  ' jump to no data if we timeout
  ' else send an acknowledge "!" to let the PC know we
  ' received the data.
  ' Also echo the command.
  SERIN 16, 1021, 5000, No_Data, [result]
  SEROUT 16, 1021, ["!"]
  SEROUT 16, 1021, [result]

No_Data:
  'Process if result equals "1" or ASCII $31
  IF result = $31 THEN
    SEROUT 16, 1021, ["HELLO", CR]
  ENDIF

GOTO Main

The VB logic needs to resend 0x30 (anything other than 0x31) if the acknowledge character is not received within some period of time (timeout). Once "!" is received then proceed to close the port. The STAMP does not handle parallel tasks. It could be working on something else when the VB app sends the stop command.

When you open the port, send 0x31 until the "!" is received.

Notice the PBasic logic is echoing the command. That's because you're listening for the Data_ Received event which is executing on a secondary thread. When you see a "!" the next byte is the last command. I'd roll up a listener (delegate) in the button close/open event and fire off an event when the "!" is received. You can also save the state of which button was pressed, then when you see the "!", read the state and handle.

You could poll the serial port over using the SerialPort.DataReceived event. Polling will be a little easier.

[Edit]: This is .NET source I used for testing cross platform serial port communication. It uses a timer to poll the serial port because Mono (on Linux) does not implement the DataReceived event. It's C# though.

Mike G

tbare, I just noticed... this is bad.

    Private Sub SerialPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles COMPort.DataReceived
        Counter += 1
        Call updateText(Counter)
        If Counter Mod 200 = 0 Then
            COMPort.Close()
            COMPort.Open()
        End If
    End Sub

I'm guessing that you're closing the port after 200 DataReceived events to clear the receive buffer? You're asking for trouble. Also there is not guarantee that impression count = DataReceived count. Consider reading the buffer and making a decision on the data received.

tbare

yeah -- basically, after about 4000 impressions, my counter would go crazy, and start spinning like a stopwatch. after i closed and re-opened the port after every 200 counts, the problem went away... I think the buffer things is a better way to go. I'll look into that and see if i can clear the buffer on the stamp itself, rather than close / open.

Thanks again for all the help! again, being a rookie in a new game is always difficult.

Mike G

tbare, the buffer is in the PC not the STAMP. The STAMP does not have a buffer.

Anyway, the .NET and PBasic code provided has what you need to complete the project. Did you, by chance, run the code?

tbare

yeah - the code is working.. Thanks a ton.

If I run into anything else, I'll post back.

again, the help is MUCH appreciated!

tbare

Hey, Mike -- In what version of VB did you write the C# code? I tried opening it in my VB 2005, but it said it was newer. Just wondering what version i need to install on a test machine so I can see what you did. I'm still having some issues getting my VB app to get the "!" back...

EDIT - I got pulled onto a more pressing project -- i haven't been working on this non-stop since my last post.. just throwin' that out there...

tbare

Never mind... i think i got that part... unfortunately, my app is still locking up after it closes -- I've put stops in to try to track down what's happening, but write after it closes the connection, it just freezes... I'll have to track it down.

here's my stop code, though:

    Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click
        Dim wrt As Byte = 0
        If COMPort.IsOpen = True Then
            While (True)
                COMPort.WriteLine(wrt)
                Thread.Sleep(50)
                If COMPort.ReadExisting.ToString.Contains("!") Then Exit While
            End While
            COMPort.Close()
        End If
    End Sub

and here's my BASIC stamp:

' {$STAMP BS2}
' {$PBASIC 2.5}

result          VAR   Byte
recdResult      VAR   Byte
result2         VAR   Byte
btnwrk          VAR   Byte
Btn             PIN   0
red             PIN   10
green           PIN   11

result    = 0
result2   = 1

' Flash LEDs
HIGH red
PAUSE 250
LOW red
PAUSE 250
HIGH green
PAUSE 250
LOW green

Main:
  SERIN 16, 16468, 2, StartCounting, [DEC result]
  recdResult = result
  result = 0
  SEROUT 16, 16468, ["!"]


StartCounting:
  'Process if result equals "1" or ASCII $31
  IF recdResult = 1 THEN
    LOW red
    HIGH green
    'SEROUT 16, 1021, [38]

    BUTTON Btn, 1, 255, 20, btnwrk, 0, No_Press : DEBUG "*" 'send * to output for each impression

    No_Press:
      GOTO Main

  ENDIF

 IF recdResult = 0 THEN
   LOW green
   HIGH red
   'SEROUT 16, 16468, ["!"]
 ENDIF

GOTO Main

tbare

So, if I add a MsgBox("blah") right before my COMPort.Close(), the msgbox takes various amounts of time to appear (b/w 1/4 second and 3 seconds), but it always closes, and never locks.

Any thoughts as to what may causing this, and a good solution to bypass it w/out a msgbox? I've tried a thread.sleep(4000), but it doesn't help... I'm sure i could do a loop for a few seconds, but that seems like a bad work-around.

Thanks!

Mike G

tbare, the C# code (not VB) was written in Visual Studio 2010. I can convert it to 2005 if you like or you can download C# Express from Microsoft. The syntax will remain C#.

Any thoughts as to what may causing this, and a good solution to bypass it w/out a msgbox?

I'm guessing you're having a problem understanding multi-threaded applications. It's hard to tell with out seeing all your code.

SERIN 16, 16468, 2, StartCounting, [DEC result]

Change the baud to 2400 max (16780) and remove the DEC formatter from [DEC result].

STAMP Manual wrote:

*The BS2, BS2e and BS2pe may have trouble synchronizing with the incoming serial stream
at this rate and higher due to the lack of a hardware input buffer. Use only simple variables
and no formatters to try to solve this problem.

tbare

Here's the full testing code:

Imports System
Imports System.IO.Ports.SerialPort
Imports System.IO.Ports
Imports System.Threading

Public Class Form1
    Delegate Sub SetTextCallback(ByVal [text] As String) 'to change the text with threadging
    Public WithEvents COMPort As New System.IO.Ports.SerialPort
    Public Counter As Integer = 0
    Public PortAvailable As Boolean = False
    Public StampReturned As String = ""

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim ports As String() = GetPortNames()
        Dim com As String = "COM4"

        ' Check each available COM port for specified port
        Dim port As String
        For Each port In ports
            If port = com Then
                COMPort.PortName = com
                COMPort.BaudRate = 9600
                COMPort.DataBits = 8
                COMPort.Parity = IO.Ports.Parity.None
                COMPort.StopBits = IO.Ports.StopBits.One
                PortAvailable = True
            End If
        Next port
        If PortAvailable Then
        Else
            MsgBox(com & " not available")
            End
        End If
    End Sub

    Private Sub SerialPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles COMPort.DataReceived
        If COMPort.ReadExisting.ToString.Contains("!") = False Then
            Call updateText2(COMPort.ReadExisting.ToString)
            Counter += 1
            Call updateText(Counter)
            If Counter Mod 200 = 0 Then
                COMPort.DiscardInBuffer()
                COMPort.DiscardOutBuffer()
            End If
        End If
    End Sub

    Private Sub updateText(ByVal [Text] As String)
        If Me.lblComOut.InvokeRequired Then
            Dim d As New SetTextCallback(AddressOf updateText)
            Me.Invoke(d, New Object() {[Text]})
        Else
            Me.lblComOut.Text = [Text]
        End If
    End Sub

    Private Sub updateText2(ByVal [Text] As String)
        If Me.TextBox1.InvokeRequired Then
            Dim d As New SetTextCallback(AddressOf updateText2)
            Me.Invoke(d, New Object() {[Text]})
        Else
            Me.TextBox1.Text = [Text]
        End If
    End Sub

    Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click
        Dim wrt As Byte = 0
        If COMPort.IsOpen = True Then
            While (True)
                COMPort.WriteLine(wrt)
                Thread.Sleep(5)
                If COMPort.ReadExisting.ToString.Contains("!") Then Exit While
            End While
            'Thread.Sleep(2000)
            If COMPort.IsOpen = True Then
                MsgBox("here")
                COMPort.Close()
            End If
        End If
    End Sub


    Private Sub btnGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGo.Click
        If COMPort.IsOpen = False Then
            COMPort.Open()
        End If
        Dim wrt As Byte = 1
        If COMPort.IsOpen = True Then
            While (True)
                COMPort.WriteLine(wrt)
                Thread.Sleep(5)
                If COMPort.ReadExisting.ToString.Contains("!") Then Exit While
            End While
        End If
    End Sub

End Class

and the stamp:

' {$STAMP BS2}
' {$PBASIC 2.5}

result          VAR   Byte
recdResult      VAR   Byte
result2         VAR   Byte
btnwrk          VAR   Byte
Btn             PIN   0
red             PIN   10
green           PIN   11

result    = 0
result2   = 1

' Flash LEDs
HIGH red
PAUSE 250
LOW red
PAUSE 250
HIGH green
PAUSE 250
LOW green

Main:
  SERIN 16, 16468, 2, StartCounting, [DEC result]
  recdResult = result
  result = 0
  SEROUT 16, 16468, ["!"] 'message received


StartCounting:
  'Process if result equals "1" or ASCII $31
  IF recdResult = 1 THEN
    LOW red
    HIGH green
    'SEROUT 16, 1021, [38]

    BUTTON Btn, 1, 255, 20, btnwrk, 0, No_Press : SEROUT 16, 16468, ["*"] 'send * to output for each impression

    No_Press:
      GOTO Main

  ENDIF

 IF recdResult = 0 THEN
   LOW green
   HIGH red
 ENDIF

GOTO Main

Everything is working as expected now, except the stop - I'll look more into the multi-threading, as i agree that this is probably where i'm having my issues.

like i said, the counter works as expected, just closing the connection doesn't... if I comment out the "COMPort.Close()" line, it works fine, still... but wouldn't that be bad form to leave the connection open like that? seems like a bad idea. I'd much rather open and close the connection for each use.

As far as 2010, i'm pretty sure we have a copy i can use for testing under our ActionPack. I'll check. and converting from C# to VB.NET isn't an issue...

Thanks again for all your help.

Mike G

There are three glaring issues with your code.

1) Counter is counting the number of DataReceived events not the number of impressions from a press!
2) You're receiving data but not reading the data, just plopping it on the screen.
3) The DataReceived handler is operating on a secondary thread while the btnStop_Click handler is invoked for the primary thread.

Clicking the Stop button invokes a write to the serial port from the primary thread. The primary is put to sleep for 5ms but DataReceived handler is not asleep!

Unsoundcode

Great observations from Mike and such an easy thing to miss. One way you could handle it is to create a boolean variable that is a condition for all running processes you want to stop when you close the port.

for example

Dim Port_Closing As Boolean=True

When you open the port:-

Port_Closing=False

In you Data Received event:-

If Not Port_Closing Then

****Do your receiving here****

End If

And when you close the port:

Port_Closing=True

add a short delay here to allow time for everything to finish

Jeff T.

tbare

1) for each impression, the press closes a circuit simulating a button press - this is why i'm ussing BUTTON for this task - I've tested this on the press, and i get the desired result.
2) This is my test app - I don't actually care "what" the information is during the DataRecieved handler - but if there is data recieved, i'm counting it as an impression, adding 1 to a variable, then every 250, writing it out to a database, with a final count written out when the stop button is pushed. - the data doesn't have to be perfect, but it needs to be closer than what they're getting now (which isn't counting any waste at all...)

3) -- let's focus on this one, as it appears to be the bulk of the issue. I'm not very familiar with threading, so my question is how do you know that it's on a secondary thread? Any thoughts on how I would resolve this mistake?

tbare

Jeff -

I tried your suggestion w/ the PortClosing boolean, but it still locks, even with a 5 second sleep after i set the boolean to true and before i attempt to close the port.

Private Sub SerialPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles COMPort.DataReceived
        If COMPort.ReadExisting.ToString.Contains("!") = False And PortClosing = False Then
            Call updateText2(COMPort.ReadExisting.ToString)
            Counter += 1
            Call updateText(Counter)
            If Counter Mod 200 = 0 Then
                COMPort.DiscardInBuffer()
                COMPort.DiscardOutBuffer()
            End If
        ElseIf PortClosing = True Then
            COMPort.DiscardInBuffer()
            COMPort.DiscardOutBuffer()
        End If
    End Sub

    Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click
        Dim wrt As Byte = 0
        If COMPort.IsOpen = True Then
            While (True)
                COMPort.WriteLine(wrt)
                Thread.Sleep(5)
                If COMPort.ReadExisting.ToString.Contains("!") Then Exit While
            End While
            PortClosing = True
            Thread.Sleep(5000)
            If COMPort.IsOpen = True Then
                'MsgBox("here")
                COMPort.Close()
            End If
        End If
    End Sub

    Private Sub btnGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGo.Click
        PortClosing = False
         {snip}
    End Sub

i'm sure it's still the multi-threading issue - i just don't know how to resolve it.

Thanks.

Mike G

Working within your constraints from #18, the easiest thing to do is programmaticly remove the COMPort.DataReceived delegate when the Close button is clicked. Then repeatedly issue the close message and listen (polling) until you get the acknowledgement byte from the STAMP. Clean up your objects and close the port.

Remember to assign the COMPort.DataReceived delegate to SerialPort_DataReceived when the Open button is clicked.