Once up-and-running, pylibftdi is designed to be very simple, but sometimes getting it working in the first place can be more difficult.
This indicates a conflict with FTDI’s own drivers, and is (as far as I know) mainly a problem on Mac OS X, where they can be disabled (until reboot) by unloading the appropriate kernel module.
Unload the kernel driver:
sudo kextunload /System/Library/Extensions/FTDIUSBSerialDriver.kext
To reload the kernel driver, do the following:
sudo kextload /System/Library/Extensions/FTDIUSBSerialDriver.kext
To permanently remove the driver, just delete it:
sudo rm /System/Library/Extensions/FTDIUSBSerialDriver.kext
Whereas earlier versions of OS X didn’t include an FTDI driver directly - it would typically be installed as part of some other program - Mavericks includes this in the operating system itself. For this reason, it’s probably a bad idea to delete it, but it can be unloaded as follows:
sudo kextunload -bundle-id com.apple.driver.AppleUSBFTDI
Similarly to reload it:
sudo kextload -bundle-id com.apple.driver.AppleUSBFTDI
Getting a list of USB devices
Start ‘System Information’, then select Hardware > USB, and look for your device. On the command line, system_profiler SPUSBDataType can be used. In the following example I’ve piped it into grep -C 7 FTDI, to print 7 lines either side of a match on the string ‘FTDI’:
ben$ system_profiler SPUSBDataType | grep -C 7 FTDI
UM232H:
Product ID: 0x6014
Vendor ID: 0x0403 (Future Technology Devices International Limited)
Version: 9.00
Serial Number: FTUBIOWF
Speed: Up to 480 Mb/sec
Manufacturer: FTDI
Location ID: 0x24710000 / 7
Current Available (mA): 500
Current Required (mA): 90
USB Reader:
Product ID: 0x4082
Use lsusb. Example from my laptop:
ben@ben-laptop:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 008 Device 011: ID 0a5c:217f Broadcom Corp. Bluetooth Controller
Bus 002 Device 009: ID 17ef:481d Lenovo
Bus 002 Device 016: ID 0403:6014 Future Technology Devices International, Ltd FT232H Single HS USB-UART/FIFO IC