Now that the project has been created, you need to change two more
settings before we can move on. Go to the Project Navigator panel in the
top left area of Quartus and right click on the device ("Cyclone IV E:
..."). Select "Device" from the menu.
A window will open. Click "Device and Pin Options...". In the left hand side of the new window that comes up, open the "Unused Pins" category. Change the "Reserve all unused pins" settings to "As input tri-stated". This will essentially prevent the unused pins on the FPGA from doing anything unwanted on the DE0-Nano when we program the design.
Now select the "Voltage" category. Change the "Default I/O standard" to "3.3-V LVTTL". This is essential to do because the panels will not recognize a signal below this voltage.
Click OK, then click OK again.