labVIEW and FTDI UM232H USB Module

[kevin_khan]

Hi there,

I was wondering if anyone has ever worked with the FTDI UM232H High Speed USB module, and tried programming it with LabVIEW.  I would like some help in trying to figure out how to program my module such that it will read a specified number of bytes.  The way the USB is currently set up, is that it will read the data being written to it and package it into packets (the packets have to be of multiples of 512 bytes), and then send it back to the computer.  However the way me data is being streamed from the hardware side is in packets of 8162 bytes (which is not a multiple of 512 bytes).  I was wondering if anyone might know how to force my USB module to read a specific number of bytes without having to package into packets and perhaps provide a small example, if it is not too much trouble. 

I should mention that I am using the D2XX drivers to program my module.

[Wart]

There's a great deal of information about USB stuff here:

http://forums.ni.com/t5/LabVIEW/Nugget-1-of-n-GEtting-started-with-USB-communication-via-VISA/m-p/74...

http://forums.ni.com/t5/LabVIEW/Nugget-2-of-n-USB-Control-transfers-using-VISA/m-p/757011/highlight/...

http://forums.ni.com/t5/LabVIEW/USB-Nugget-3-of-n-Unifying-the-multitude-of-USB-driver/m-p/1814964/h...

I've never done any USB communication, so I probably won't be of any help.  Hopefully that will get you started though.

[kevin_khan]

Thanks for this.  It was not what I am really looking for, but I am sure this information would come in handy for future reference.

[ron64]

hello, 

i have been working with D2XX library using C# with platform invoke for years.

also, since LV has a facility which accepts .NET DLLs, I have used this in the past as well;

one example;

airpcap wifi packet sniffer;

API for Airpcap at the time was WIN32 DLL API.  

So, pushed that into c# DLL and used platform invoke to map the functions into managed c# space

next, at the time, I called that c#.net library from LV.  

If you are interested in my services for subcontract please let me know

cheers

[fblerg]

Hi Kevin,

There are two examples on the FTDI Chip website that might be good starting points for using the FTDI USB chip. The examples use the ftd2xx.dll and the Call Library Function Node in LabVIEW to access the dll functions.

Another option would be to use the Virtual COM Port Driver and access the chip as a serial COM port. You can use the VISA function to talk to the chip and configure the Read/Write functions accordingly. From the FTDI site, “Virtual COM port (VCP) drivers cause the USB device to appear as an additional COM port available to the PC.  Application software can access the USB device in the same way as it would access a standard COM port.”

LabVIEW Examples

http://www.ftdichip.com/Support/SoftwareExamples/CodeExamples/LabVIEW.htm

Virtual COM Port Drivers

http://www.ftdichip.com/Drivers/VCP.htm 

[ron64]

hi Frank,

the driver is actually dual purpose which changes based on how it is used; 

vcp if you choose to use RS232 protocol

or D2XX if you choose to use the USB read/write library.  

you don't have to press a button for force it into vcp mode or vice-versa 

these were separate in the past but they brought them together a couple of years ago. 

Ron