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FTDI Virtual Comm Port (VCP) drivers on a PXI-8176 RT System

I am trying to get a PXI-8176 to communicate with a serial device using the FTDI VCP (virtual comm port) drivers. 


When I connect the device to the Windows host machine, it is recognized as a VCP (com24).  The VI's that I have employed are able to communicate with the device through the VISA Serial VI's.  Everything works fine in the Windows environment. 


A PXI-8176 has been configured and tested for RT application; I am able to execute DAQ functionality and transmit the data to the host PC via shared variables.  When I plug the FTDI device into the PXI unit, MAX populates the "Devices and Interfaces" section of the PXI with a USB device that is given the following assignment:




There is no VCP populated in the "Serial" section on the PXI unit.  Using the above resource in a VISA Serial VI doesn't work (errors ensue on execution); this resource is a RAW USB device. 


How do I configure the PXI unit to create VCP's when an FTDI device is connected, as it is on the host machine? The goal is to have a VCP on the PXI unit so that I can implement the VISA Serial VI's to interface with the serial device through the FTDI chip. 

I would



I am using the following hardware and software:


Host PC: Windows XP 32-bit

LabVIEW 2011

LabVIEW Run-Time 11.0

MAX 5.1.0f0




Target: NI PXI-8176 in a PXI-1002 chassis

LabVIEW Real-Time 11.0



FTDI chip: FT232BL




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Hi taylorce,


The reason why the FTDI device enumerates correctly in Windows and not Real-Time is because the operating system which LVRT uses, Phar Lap (http://digital.ni.com/public.nsf/allkb/35F1FD98520D6E0E8625783A005AF557), is not supported by that driver http://www.ftdichip.com/FTDrivers.htm


Since FTDI does not provide open source drivers, we are not able to support FTDI devices under LabVIEW Real-Time.



Aldo A
Applications Engineer
National Instruments
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Just saw this:




Reiterates the unsupported OS statement. 


I presume that the the FTDI D2XX drivers would result in the same failure as the VCP drivers; unsupported OS for the PXI unit.  I have contacted FTDI to see if there is anything that they can recommend.  

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For those in the future that will read this post, I am including the communication from FTDI that I solicited in response to this dilemma.  This might help with anyone that is brave, or has the requisite skills, to undertake a custom driver project.  I have neither of the aforementioned qualities and will be seeking alternate solutions, which I will post here once they are developed. 





I am working with a National Instruments Real-Time Operating System (RTOS) on a NI-PXI-8176 Real-Time (RT) Controller.  I would like to interface some of the microcontrollers that are my test system with this RT unit, which I have utilized your FTDI FT232BL chips for communication capabilities.  In the windows environment, I have successfully been able to implement your VCP drivers for these devices and utilize the LabVIEW Serial commands.  However, I have been told by NI that this will not work for my RT unit application, as these drivers are not supported by the RTOS.  They indicated that your drivers are not open source, and this prevents them from developing a driver for their RTOS. 

Is there anything that you can recommend that would allow me to utilize your products with this RTOS?  I have been told that the D2XX drivers would have the same issue; OS incompatibility.  Thank you.

This is the post on the NI discussion boards, with a response from an engineer at NI.







That is correct. Our drivers are proprietary.


To develop your own drivers for the RTOS you will need to sign an NDA before documentation pertaining to the hardware details of the device can be released.


You will need to use this along with a USB bus analyser and will need to keep USB-IF specifications handy to write your own driver for the RTOS.


Let me know if you would like to proceed this route and I will put in a request to see if we can get an NDA out to you.





[FTDI Engineer],

Thank you for your quick reply.  Unfortunately, I think this solution is outside my expertise and capabilities.  I will see if I can bring someone in on this assignment who would have an appropriate skill set.  Are there any solutions to this issue (e.g. hardware, software) that are available for purchase?  Thank you for your time.







The only open source drivers available are the libftdi for linux which is based off of libusb. We do not support it but there are plenty of users that use this library.



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