How to use the FTDI D2XX library on OSX?

Question

I'm trying to talk to a an usb device connected to an EasySync USB2-H-5004-M USB to RS485 converter at baud rate 3750000 but on OSX.

I've some c++ code working on Windows and have just managed to get it to compile on OSX (using the D2XX dylib instead of the dll) but I have an issue with communication somewhere and I'm not sure where to start and how to resolve this.

I'm using openFrameworks/c++ and the method to list devices looks like this:

int FTDI::enumerateDevices(){
    DWORD numDevs;
    FT_STATUS ftStatus = FT_CreateDeviceInfoList(&numDevs);
    numPortsFound = 0;

    if (ftStatus == FT_OK) {
        ofLog(OF_LOG_NOTICE, "Number of FTDI devices is %d",numDevs);
        devicesList = (FT_DEVICE_LIST_INFO_NODE*)malloc(sizeof(FT_DEVICE_LIST_INFO_NODE)*numDevs);
        ftStatus = FT_GetDeviceInfoList(devicesList, &numDevs);
        if (ftStatus == FT_OK) {
            printf("\n");
            for (int i = 0; i < numDevs; i++) {
                ofLog(OF_LOG_VERBOSE, "Dev %d:",i);
                ofLog(OF_LOG_VERBOSE, " Flags=0x%x",devicesList[i].Flags);
                ofLog(OF_LOG_VERBOSE, " Type=0x%x",devicesList[i].Type);
                ofLog(OF_LOG_VERBOSE, " ID=0x%x",devicesList[i].ID);
                ofLog(OF_LOG_VERBOSE, " LocId=0x%x",devicesList[i].LocId);
                ofLog(OF_LOG_VERBOSE, " SerialNumber=%s",devicesList[i].SerialNumber);
                ofLog(OF_LOG_VERBOSE, " Description=%s",devicesList[i].Description);
                ofLog(OF_LOG_VERBOSE, " ftHandle=0x%x\n",devicesList[i].ftHandle);
            }
            numPortsFound = numDevs;
        } else {
            ofLog(OF_LOG_ERROR, "FTD2XX::FT_GetDeviceInfoList() failed");
        }
    } else {
        ofLog(OF_LOG_ERROR, "FTD2XX::FT_CreateDeviceInfoList() failed");
    }

    return numPortsFound;

}

The problem is on OSX I get this output:

[notice ] Number of FTDI devices is 4

[verbose] Dev 0:
[verbose]  Flags=0x1
[verbose]  Type=0x3
[verbose]  ID=0x0
[verbose]  LocId=0x0
[verbose]  SerialNumber=
[verbose]  Description=
[verbose]  ftHandle=0x0

[verbose] Dev 1:
[verbose]  Flags=0x1
[verbose]  Type=0x3
[verbose]  ID=0x0
[verbose]  LocId=0x0
[verbose]  SerialNumber=
[verbose]  Description=
[verbose]  ftHandle=0x0

[verbose] Dev 2:
[verbose]  Flags=0x1
[verbose]  Type=0x3
[verbose]  ID=0x0
[verbose]  LocId=0x0
[verbose]  SerialNumber=
[verbose]  Description=
[verbose]  ftHandle=0x0

[verbose] Dev 3:
[verbose]  Flags=0x1
[verbose]  Type=0x3
[verbose]  ID=0x0
[verbose]  LocId=0x0
[verbose]  SerialNumber=
[verbose]  Description=
[verbose]  ftHandle=0x0

[ error ] failed to register FTDI device with serial FTWVZVEBA in internal register
[ error ] error opening port with serial: FTWVZVEBA

which doesn't look right. For example on Windows, on port A/channel 1/device index 0 I see this:

[verbose] Dev 0:
[verbose]  Flags=0x2
[verbose]  Type=0x7
[verbose]  ID=0x4036011
[verbose]  LocId=0x02111
[verbose]  SerialNumber=FTWVZVEBA
[verbose]  Description=USB2-H-5004-M A
[verbose]  ftHandle=0x0

Having a quick look in /dev things look ok:

ls /dev/tty.*
/dev/tty.Bluetooth-Incoming-Port    /dev/tty.usbserial-FTWVZVEBB
/dev/tty.Bluetooth-Modem        /dev/tty.usbserial-FTWVZVEBC
/dev/tty.usbmodemfa131          /dev/tty.usbserial-FTWVZVEBD

and through System Information I get:

USB2-H-5004-M:

  Product ID:   0x6011
  Vendor ID:    0x0403  (Future Technology Devices International Limited)
  Version:   8.00
  Serial Number:    FTWVZVEB
  Speed:    Up to 480 Mb/sec
  Manufacturer: FTDI
  Location ID:  0xfd120000 / 4
  Current Available (mA):   500
  Current Required (mA):    200

I have installed the D2XX driver as instructed on the FTDI OSX Installation Guide (pdf link) but I'm not sure what I'm missing/doing wrong.

How can I correctly communicate to the device using the FTDI D2XX library ?

Not sure about the FTDI library. Can you do something trivial like use cu(1) to open the port and send/receive data? — janm, Nov 04 '13 at 23:19
Can you please give me a bit of into on that ? Here's my first shot at using cu: `cu -l /dev/tty.usbserial-FTWVZVEBA --baud 3750000 cu: creat during lock (/var/spool/uucp/TMP0000000cee in /Users/weblab as uid 501): Permission denied cu: /dev/tty.usbserial-FTWVZVEBA: Line in use` — George Profenza, Nov 05 '13 at 10:49
First, use "sudo". Something like `sudo cu -l /dev/whatever ...`. You will need to enter your password. The permission problem here is probably just uucp locking rather than the port itself; you can check the port permissions by doing `ls -l /dev/tty.usbserial-whatever`. — janm, Nov 05 '13 at 11:12
Thank you. If I don't specify the port I see a connected message, but if I do I see that the baud rate I need to use is unsupported: `sudo cu -l /dev/tty.usbserial-FTWVZVEBA -s 3750000 cu: Unsupported baud rate 3750000`. I remember seeing something about changing a Info.plist file in FTDIUSBSerialDriver.kext to add support for previously unsupported baud rates, but that was for VCOM FTDI drivers. I think I'm just using D2XX now. Is there an equivalent hack for the D2XX driver / do I have to install the VCOM driver and do the .kext baud tweak first ? — George Profenza, Nov 05 '13 at 11:35
I can't help you on the FTDI custom interface. Try a standard baud rate to make sure you are even dealing with the right device and the device works first. You should be able to use tcsetattr to set a line speed that cu might not support. If that fails, then you are into a ftdi special case. — janm, Nov 06 '13 at 01:18
Is this running on 10.9 (Mavericks)? There's a [new kext that ships in 10.9](https://devforums.apple.com/message/828411#828411) which acts like the VCP FTDI drivers. It unfortunately disables the D2XX libraries unless you unload it (`sudo kextunload -b com.apple.driver.AppleUSBFTDI`), which might be why you see a failure to connect using the FT_ functions. — Brad Larson, Nov 08 '13 at 20:21
@BradLarson Wow! This is using 10.9 Mavericks. I will be able to test in the morning. It sounds like my fix. Thanks Brad! — George Profenza, Nov 08 '13 at 20:25
@BradLarson Thanks Brad, I have tested and unloading the apple kext does the trick! Everything else works as expected after that. When you get a chance, please add your comment as an answer so I can vote/award it :) — George Profenza, Nov 09 '13 at 16:11

score 9 · Accepted Answer · answered Nov 11 '13 at 23:00

To flesh out my comment, since it seems to have answered the core question here: Mac OS 10.9 (Mavericks) now ships with a kernel extension that acts like FTDI's VCP drivers did. It creates a virtual comm port for FTDI USB-to-serial devices it detects, and means that you no longer have to install the VCP driver if you needed it before.

This has an unfortunate side-effect, though, in that it breaks any application using FTDI's D2XX library. This exhibits itself as a failure for the D2XX functions to connect to the FTDI device, even though they can see it. As a work-around, you can manually unload the kext:

sudo kextunload -b com.apple.driver.AppleUSBFTDI

but it will reload itself on next boot.

As a more permanent solution, I've been having my applications detect if this kext is loaded (by trying to connect via the D2XX functions and seeing if they fail), and using the more traditional open(), etc. calls for connecting to the serial port as a fallback.

I'm not sure if the VCP-style kext they use allows for as much flexibility in terms of baud rates as the D2XX one does, though.

Thank you for posting the answer. Because I needed to use a non-standard baud rate(3750000), for my setup, I chose to use the D2XX driver after disabling the AppleUSBFTDI kext first. The command can be saved a startup bash script or unloaded/loaded as a system call from the application to be more sensitive to other apps that potentially rely on the VCP version — George Profenza, Nov 12 '13 at 13:12

score 0 · Answer 2 · answered Oct 26 '18 at 18:18

0

As mentioned in Brad Larson's answer, you need to unload the Apple FTDI kext for the D2XX library to work, on later versions of MacOS. However, FTDI have a script that automatically does this for you, called D2XX Helper, linked to in the Comments box under the Mac OS X row on the D2XX drivers page.

answered Oct 26 '18 at 18:18

Tim MB

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That worked then, D2XX Helper and [FTDI Driver Control](http://www.dmxis.com/macdriverfix/) helped in the past, but recently I ran into a [separate issue](https://github.com/ROBOTIS-GIT/DynamixelSDK/issues/223) that either wouldn't let me unload the driver or wouldn't let go of the device without a reboot: the solution in this particular case was to get rid of the D2XX driver completely and use the AppleUSBFTDI driver instead (the exact opposed of what worked 5 years ago :)) ) – George Profenza Oct 26 '18 at 21:19

How to use the FTDI D2XX library on OSX?

2 Answers2

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