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General Visual Basic Example using USBm.dll
This example uses VB to interface to the U4xx. The very minimum application would be to open the USB device and transmit a single command. This example shows the code that it takes to use USBm.dll to open the U4xx device and initialize the ports.
|Public Declare Function USBm_About _|
Lib "USBm.dll" _
(ByVal aboutstring As String) _
The declaration for the file "USBm.dll" is included in the Visual Basic project by including the file "USBmAPI.bas". This example declaration above will return the "about" string contained in the DLL. All of the DLL functions are declared in "USBmAPI.bas".
| USBm_About strng|
frmMain.lstInfo.AddItem "About the USBm DLL: " & strng
This code fragment shows that strng is loaded with the "about" text of the DLL. Assuming that the form called "Main" exists with a text box called "Info", the "about" information will be made visible to the user.
|Dim w As Integer|
' Search for device(s)
w = USBm_FindDevices
' Test return value
If (w) Then
frmMain.lstInfo.AddItem (" Devices found.")
frmMain.lstInfo.AddItem (" Devices not found.")
This code fragment shows the call needed in order to find the devices on the bus. This DLL function needs to be called before any other device communication. Assuming that the form called "Main" exists with a text box called "Info", the found⁄not found message will be made visible to the user.
This code fragment initializes the ports of device 0.
|Hardware: U401 USB Interface U421 USB Interface U451 USB Interface|
Programming: USBm DLL Programming Download Files
Application Notes: U4x1 Application Notes Misc Applications and Information FAQ
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