libftdi Archives

Subject: Re: Use of ftdi-sio and libftdi on different interfaces of the same instance of FT4232 (and similar)

From: Xiaofan Chen <xiaofanc@xxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Thu, 30 Sep 2010 18:56:08 +0800
On Thu, Sep 30, 2010 at 5:52 PM, Ales Teska <ales.teska@xxxxxxxxx> wrote:
> Now problem is that obviously it is not possible today to configure
> ftdi-sio a libftdi to share same USB device. Right?
> I assume that if ftdi-sio 'locks' USB device, then it is not possible to
> speak with that thru libusb/libftdi.

You should be able to use ftdi-sio for one interface (channel) and use
libftdi on the other interface (channel). FT2232x are USB composite
device which will be enumerated as two device. To use libftdi (based
on libusb), you need to detach the kernel driver for that interface.

But I myself have not tested this.

> It is possible to split device use this way on Windows and with vendor
> D2XX library (on Linux they have the same issue).

It is certainly possible to use libftdi for one interface and
FTDI D2XX or VCP for the other interface under Windows. Just
switch one of the channel to use libusb-win32 device
driver and keep the FTDI driver for the other channel.

I have done this many times (to test libftdi and OpenOCD).

You can use the libusb-win32 inf-wizard for this purpose.
Download the latest from Sourceforge.


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