FTDI Driver Problem

[11MW99]

Hello,

I want to read/write from/to an FT2232H(FTDI FT2232H Mini Module).

I have the D2XX drivers installed on my Windows 7 before I installed Labview recently.

Using C# or C++ applications I can read write trough this drivers.

In NI MAX it not appears when plugging it into my Computer. But it appears in the Windows Device Manager.

I have another TTL cable from FTDI, this one appears in NI MAX when I plug it in.

Do I have to set some paths or tell NI MAX or Labview about the drivers?

What else I can do?

I use the community version, is this a limitation?

Thanks,

Mark

[GerdW]

Hi Mark,

why don't you use the VCP option of the driver support, with some VISA functions in LabVIEW?

[11MW99]

Thanks Gerd,

I will look into this option with VCP. Thats probably a good idea as a start.

I am a bloody beginner with Labview, just taking my first steps.

Finally I want to be able to transfer about 12 MB/s over the FT2232H.

[rolfk]

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@11MW99 wrote:

Finally I want to be able to transfer about 12 MB/s over the FT2232H.

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You can of course want to do that, but that is not going to work. 12MB/s is ~100Mb/s and no FTDI chip is capable of handling that in any serial port implementation. Now if you meant 12M baud then that’s the theoretical maximum baudrate of this chip, But expect some struggles on the way. I’m not sure you can convince the Windows COMM interface to go that high and then the VCP mode won’t work. Even if you get that high you’ll need to do some smart programming too in your LabVIEW code. The Windows COMM interface was designed for Windows 3.x when 56k Baud was considered high end supper speed modem interfaces!

[11MW99]

Thanks Rolf,

I think I will start with VCP first to get some experience in Labview.

Then later I will look into other ways to get 12 MB/s.Seems there is not much documentation about that.

Mark

[DavidBoyd]

I'll second Rolf's opinion here, I *think* you may be confused by the maximum datarate of a USB2.0 interface, which probably isn't the relevant spec, and I hope that you just mis-quoted your goal.  Apart from lots of more routine FTDI-chipset serial ports I've used, more recently I've used one of the overmolded OEM FTDI interfaces (TTL-232R or some variant of that part number, it was a molded USB A plug to pigtailed leads - a full modem asynch interface at 3V or TTL logic levels).  I had reliable communication out to 921.6k baud, which is a "standard" value (inasmuch as it's 8 times 115.2k).  I don't recall if the interface and/or the driver supported higher rates - their RS-485 version may go up to 3M baud.

But for the application at hand (re-flashing a ginormous serial EEPROM outboard of an STM32 microcontroller, under control of STM32 code), it felt pretty fast! 🏎

Dave

[rolfk]

Hi Dave

The data sheet for the FT2232H does state two things among others 

• USB 2.0 High Speed (480Mbits/second) and Full Speed (12Mbits/second) compatible.
• RS232/RS422/RS485 UART Transfer Data Rate up to 12Mbaud. (RS232 Data Rate limited by external level shifter).

Now the 480 Mbit is a total theoretical value. There is no practical setup where you could reach that or even come close to it and that also only using isochronous data transfer, which the FTDI chip does not use. All communication between host and chip happens with normal request transactions (in other words simple polling).

And the more relevant 12 M Baud here only says that the chip has a clock circuitry that allows to go up to that baudrate, not that you can reliably implement that through any type of hardware driver (level shifter, cable length, other circuitry) and even more important and normally less user determinable, software driver architecture.

The Windows COMM interface never was designed for multi Mega Speeds and used to have trouble to support speeds higher than 115 kBaud. Part of the problem here also were crappy device drivers but the whole architecture wasn’t originally designed for that either. It comes from a time that is only a few years after Bill Gates claimed that nobody ever would need more than 640k Byte of memory in a computer. 😀

[11MW99]

Hi both,

I think I found some useful information here:

https://forums.ni.com/t5/LabVIEW/Labview-with-FTDI-D2XX-drivers/td-p/94458?profile.language=en

Just need to go trough it and start learning Labview a bit more. But the above tread is probably a good starting point.

Mark