libFTDI

Installation

libFTDI (http://www.intra2net.com/en/developer/libftdi/) is what we use to communicate with the Intan Demo Board. It's a free, open-source (LGPL 2.1) library for talking to FTDI chips. On Linux, you can install it through the Synaptic Package Manager or with sudo apt-get -y install libftdi-dev. On Mac, just download the package from the website and run ./configure, make, sudo make install. The library is also available through MacPorts.

It requires libusb, which is probably already on your system. If not, it's easy to download and install.

Listing USB devices

When working with USB devices, it's handy to know the following commands:

• On Linux, lsusb shows all of the available USB devices
• system_profiler SPUSBDataType does the same for Mac

Gaining permission to write to USB devices

To access FTDI USB devices on Linux without running your program as root, you'll have to carry out the following steps:

1. copy the file 40-open-ephys.rules to /etc/udev/rules.d
2. $ sudo /etc/init.d/udev restart

This will allow any user to write to a USB device with the stated attributes. The default is that only root can do this. Here's more info on udev.

To get libFTDI working at all on OS X, the following was necessary:

• $ sudo kextunload /System/Library/Extensions/FTDIUSBSerialDriver.kext

Without this, ftdi_usb_open returns -5 (unable to claim usb device). After this one line, everything works perfectly.

To make this change permanent, type sudo rm -rf /System/Library/Extensions/FTDIUSBSerialDriver.kext. Otherwise the driver will be re-loaded upon restart.

On Windows, it looks like the libFTDI .dll file will allow you to communicate with the Intan board.

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