@Xiaofan: this is very useful information. So far, I've only had success with libusb-win12, and yes, it has the problem you describe. (That's a big issue for my clients' customers.)
I tried installing libusb-1.0 using Zadig, but as you point out, I lose the bitbang functionality for the FTDI chip that we require. So I'll try the usbdk approach. I'll report back here! Thanks again. On Fri, Mar 9, 2018 at 5:25 AM, Xiaofan Chen <[email protected]> wrote: > On Fri, Mar 9, 2018 at 6:14 PM, Robert Poor <[email protected]> wrote: > > @Uwe: > > > > I confess I was slightly confused in my original note. It turns out that > > libftdi isn't causing any trouble: I can reliably wiggle the CBUS pins > under > > program control. > > > > However, other parts of our system depend upon using the FTDI part in > serial > > mode. > > > > My real problem is that I haven't found a reliable way to load a backend > > driver (e.g. libusb-win32) for use by PySerial. The manifestation is > that I > > can create a "filter" for the FTDI that makes it known to Windows, but on > > occasion (and I can't tell what that occasion is) it forgets about the > > device and I have to re-run the filter installer. > > > > So...truly this issue doesn't belong in the libftdi. However, perhaps > > someone on this list has had some experience with the problem I describe. > > > pyftdi uses pyusb, and pyusb has different backend, > libusb-0.1/libusb-win32, > libusb-1.0 and openusb. > > Even though I am the admin of libusb-win32 project (the other admin who > is the main developer, is not active now), I confess I have > not use the filter for a long time. I remember that if you insert to a > different USB port you may need to install the filter again. > > Anyway, libusb-win32 is old. So you may want to switch libusb-1.0 > backend of pyftdi/pyusb. In that case you need to use > supported driver. > > 1) Use Zadig to install WinUSB to replace vendor FTDI driver. You will > lose the FTDI vendor driver function. > 2) Use usbdk, it kinds of act as a filter driver, so the FTDI vendor driver > is still functional. > > I gather from your libftdi mailing list post that you want to use Option 2 > (usbdk). > > It is the same for users who want to use libftdi. > > -- > Xiaofan > > -- > libftdi - see http://www.intra2net.com/en/developer/libftdi for details. > To unsubscribe send a mail to [email protected] > > -- libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]
