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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

There are two steps in getting a sensible installation in Linux systems:

  1. Getting libftdi and its dependencies installed
  2. Ensuring permissions allow access to the device without requiring root privileges. Symptoms of this not being done are programs only working properly when run with sudo, giving '-4' or '-8' error codes in other cases.

Each of these steps will be slightly different depending on the distribution in use. I've tested pylibftdi on Debian Wheezy (on a Raspberry Pi), Ubuntu (various versions, running on a fairly standard ThinkPad laptop), and Arch Linux (running on a PogoPlug - one of the early pink ones).

Debian (Raspberry Pi) / Ubuntu etc

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:

$ sudo apt-get install libftdi-dev

The following works for both a Raspberry Pi (Debian Wheezy) and Ubuntu 12.04, getting ordinary users (e.g. 'pi' on the RPi) access to the FTDI device without needing root permissions:

  1. Create a file /etc/udev/rules.d/99-libftdi.rules. You will need sudo access to create this file.

  2. Put the following in the file:

    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. You could try removing the match on idProduct altogether, just matching on the FTDI vendor ID. Or 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.

Arch Linux

The libftdi package (sensibly enough) provides the libftdi library:

$ sudo pacman -S libftdi

Similar udev rules to those above for Debian should be included (again in /etc/udev/rules.d/99-libftdi.rules or similar), though the GROUP directive should be changed to set the group to 'users':

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

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 (Ben Bass) if you have any issues with installation, though be aware I don't have much in the way of Windows systems to test.

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