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pylibftdi / doc / installation.rst

Installation

Unsurprisingly, pylibftdi depends on libftdi, and installing this varies according to your operating system. Chances are that following one of the following instructions will install the required prerequisites. If not, be aware that libftdi in turn relies on libusb.

Installing pylibftdi itself is straightforward - it is a pure Python package (using ctypes for bindings), and has no dependencies outside the Python standard library for installation. Don't expect it to work happily without libftdi installed though :-)

$ pip install pylibftdi

Depending on your environment, you may want to use either the --user flag, or prefix the command with sudo to gain root privileges.

Windows

I've not tested pylibftdi on Windows, but recent libftdi binaries seem to be available from the picusb project on google code.

Mac OS X

I suggest using homebrew to install libftdi:

$ brew install libftdi

Linux

On Debian like systems (including Ubuntu, Mint, Debian, etc), the package libftdi-dev should give you what you need as far as the libftdi library is concerned.

One potential issue is with permissions to access the device, which can be seen as a error when opening devices (with a '-4' or '-8' error code). The solution is to add udev rules to deal with the devices - the following works for me under Arch linux:

SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", GROUP=="users", MODE="0660"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6014", GROUP=="users", MODE="0660"

Under other distributions, other group names are probably needed. On Ubuntu (12.04 here) I use the dialout group. Create a file /etc/udev/rules.d/99-libftdi.rules containing:

SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", GROUP=="dialout", MODE="0660"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6014", GROUP=="dialout", MODE="0660"

Some FTDI devices may use other USB PIDs. Use lsusb or similar to determine the exact values to use (or try checking dmesg output on device insertion / removal). udevadm monitor --environment is also helpful, but note that the environment 'keys' it gives are different to the attributes (filenames within /sys/devices/...) which the ATTRS will match. Perhaps ENV{} matches work just as well, though I've only tried matching on ATTRS.

Note that changed udev rules files will be picked up automatically by the udev daemon, but will only be acted upon on device actions, so unplug/plug in the device to check whether you're latest rules iteration actually works :-)

See http://wiki.debian.org/udev for more on writing udev rules.

Testing installation

Connect your device, and run the following (as a regular user):

$ python -m pylibftdi.examples.list_devices

If all goes well, the program should report information about each connected device. If no information is printed, but it is when run with sudo, a possibility is permissions problems - see the section under Linux above regarding udev rules.

If the above works correctly, then try the following:

$ python -m pylibftdi.examples.led_flash

Even without any LED connected, this should 'work' without any error - quit with Ctrl-C. Likely errors at this point are either permissions problems (e.g. udev rules not working), or not finding the device at all - although the earlier stage is likely to have failed if this were the case.

Feel free to contact me (@codedstructure) if you have any issues with installation, though be aware I don't have much in the way of Windows systems to test.