Part 1: Getting Started

In the LX Terminal :

First update the Raspberry Pi software,  sudo apt-get update

The Serial Peripheral Interface Bus or SPI needs to be enabled to allow communication between the PiFace and the Raspberry Pi. To enable this,  
sudo nano /etc/modprobe.d/raspi-blacklist.conf

hash out the spi-bcm2708, it should read as below:

#blacklist spi-bcm2708

Save and exit the file, ensure the Pi is connected to the Internet and download the drivers for the PiFace.

wget http://pi.cs.man.ac.uk/download/install.txt

Then, to run the script in the terminal, type: bash install.txt

This may take up to 30 minutes

Then restart the Raspberry Pi, sudo reboot

Easy Option:

A pre-installed OS image is available at http://pi.cs.man.ac.uk/download/ 
Diagram from Brain Lewis

Part 2: Testing the PiFace 

The PiFace comes with  pre-installed Emulator so that you can test that all the inputs, relays etc are working correctly.

The PiFace consists of:
  • 2 changeover relays
  • 4 switches (Pushbuttons)
  • 8 digital inputs
  • 8 open-collector outputs
  • 8 LED indicators
  • Graphical emulator and simulator 

In the LX Terminal :

~/piface/scripts/piface-emulator
Testing the Outputs

Select the Override Enabled, then select one of the Output Pins from the GUI. The corresponding LED on the PiFace will toggle on and off.  It is also possible to toggle ALL the LEDs using All On / Flip or All Off

Testing the Inputs

Select the Keep inputs updated, and the Inputs can be tested.  Press each of the buttons on the real PiFace and the switch will be toggled.