Unexpected Result Testing 'FirstPortCH' with PMD-1024HLS

[Scott Mackey]

Hello,

I am testing my PMD-1024HLS (same as USB-1024HLS) PortA, PortB, PortCL, PortCH using VB.net.  My code is shown below.

I am getting unexpected results when testing PortCH .  The other three ports PortA, PortB, PortCL work fine in my test.

In my test, I use both DOut() and DIn() methods.  I use DOut() to write a hex value and then DIn() method to read the value back what was written and compare it.  Am I misunderstanding the PortC nibble of PortCL and PortCH?  My question is at the bottom.

Thank you, Scott Mackey

 

'// My code starts here:

  Private _daqBoard As MccDaq.MccBoard

    Private _portA As Short          '// Byte
    Private _portB As Short          '// Byte
    Private _portCL As Short          '// Nibble low
    Private _portCH As Short          '// Nibble high
 

'// ** Constructor **************************************************************************************************

    Public Sub New(ByVal outlet As OutletType)

        Dim ULStat As MccDaq.ErrorInfo
        Dim errPort As Boolean = False

        _daqBoard = New MccDaq.MccBoard()                           '// Create instance with access to all methods

        ULStat = _daqBoard.DConfigPort(FirstPortA, DigitalOut)      '// Configure FirstPortA for output; all ports set low from this
        If (ULStat.Value <> NoErrors) Then
            errPort = True
        End If

        ULStat = _daqBoard.DConfigPort(FirstPortB, DigitalOut)      '// Configure FirstPortB for output; all ports set low from this
        If (ULStat.Value <> NoErrors) Then
            errPort = True
        End If

        ULStat = _daqBoard.DConfigPort(FirstPortCL, DigitalOut)     '// Configure FirstPortCL for output; all ports set low from this
        If (ULStat.Value <> NoErrors) Then
            errPort = True
        End If

        ULStat = _daqBoard.DConfigPort(FirstPortCH, DigitalOut)     '// Configure FirstPortCH for output; all ports set low from this
        If (ULStat.Value <> NoErrors) Then
            errPort = True
        End If

        If errPort Then
            Throw New Exception("Driver Board for AC Controller did not configure properly.")
        End If

    End Sub

'// PortA ** Works fine ***************************************************************
        _portA = &HAA

        ULStat = _daqBoard.DOut(FirstPortA, _portA)

        _portA = &H0

        ULStat = _daqBoard.DIn(MccDaq.DigitalPortType.FirstPortA, _portA)

 

'// PortB ** Works fine ****************************************************************
        _portB = &H55

        ULStat = _daqBoard.DOut(FirstPortB, _portB)

        _portB = &H0

        ULStat = _daqBoard.DIn(MccDaq.DigitalPortType.FirstPortB, _portB)

 

'// PortCL ** Works fine ***************************************************************

        _portCL = &HA       '// xxxx|1010

        ULStat = _daqBoard.DOut(FirstPortCL, _portCL)

        _portCL = &H0       '// xxxx|0000

        ULStat = _daqBoard.DIn(MccDaq.DigitalPortType.FirstPortCL, _portCL)

 

'// PortCH ** NOT READING BACK WHAT WAS WRITTEN *******************************

        _portCH = &HA0      '// 1010|xxxx

        ULStat = _daqBoard.DOut(FirstPortCH, _portCH)

        _portCH = &H0       '// 0000|xxxx

        ULStat = _daqBoard.DIn(MccDaq.DigitalPortType.FirstPortCH, _portCH)  _portCH = 00H and not A0H

 

[JRys]

Hello,

We've never promoted the abilty to read back an output port value because it was not throughly test. However, reading back a value from an internal register does not assure that the port is set to the read back value. Because of this and because the ability to read back port values was never throughly tested, we recommend to programmers that they maintain a program variable that reflectw the last written port value.

Best regards,
John