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Utilizing Features of the USB Port on my VxWorks Real-Time Controller?

Hardware: Compact FieldPoint>>Controllers, CompactRIO>>Controllers>>cRIO-9014, CompactRIO>>Controllers>>cRIO-9012

Problem:
I am using a cRIO-901x, cRIO-902x, or a cFP-22xx controller that use the VxWorks operating system and I would like to use the USB port. What are the capabilities and limitations of the USB port on these controllers?

Solution:

LabVIEW Real-Time 8.2

All Real-Time targets running LabVIEW Real-Time 8.2 use version 6.1 of the VxWorks operating system which has very stringent USB driver specifications. The host controller driver provided with VxWorks 6.1 has strictly type-cast components for different USB devices. This implies that although a particular mass storage device may be compatible with Windows or Linux, it may not work with VxWorks 6.1.

LabVIEW Real-Time 8.5 and later

All Real-Time targets LabVIEW Real-Time 8.5 and later use VxWorks 6.3. This version of the operating system has updated parameters for the USB host controller driver allowing for a wider range of values. This implies that any mass storage device such as USB Flash drives and USB-to-IDE adapters formatted with FAT16 and FAT32 file systems should function correctly.

In both the above cases, when the device is connected, it will be mapped as the u:\ drive on the controller. In order for your device to be recognized correctly as a USB storage device, keep in mind the following considerations:
  • The device must adhere to the USB mass storage device specification. Some manufacturers take liberties with this specification. If possible, choose a manufacturer that adheres rigorously to this standard to ensure compatibility with the cRIO and cFP controllers.
  • The device must be formatted with a FAT file system.
A good test to verify that your device will work as a storage device for the cRIO or cFP controller is to plug the device into a Windows computer. The device should be automatically recognized and added as a drive in My Computer.

The supported software that ships with the controllers is restricted to USB mass storage devices; no other USB drivers have been developed for these controllers. Thus, the controllers cannot natively be used to communicate with generic USB devices through the USB port. It is possible to develop a custom USB driver, but this must be done using a WindRiver VxWorks development seat.

Related Links:
KnowledgeBase 2KM92E5F: How Do I FTP to the External CompactFlash or USB drive on a RT Controller?
Developer Zone Tutorial: USB Instrument Control Tutorial
External link: WindRiver USB for VxWorks 6
KnowledgeBase 4LRA4IQ0 What Operating System is my Real-Time Controller Running and Why?

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Report Date: 07/20/2007
Last Updated: 05/06/2009
Document ID: 4BJHB69X

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