de2 board expansion header

Hi,

Cyclone-II on DE2 is set to support 3.3V I/O, since VCCIO on this board is set to 3.3V.

If your device operates on 2.5 to 5.5V, then 3.3V is certainly in that range.

To be sure you need to find this information in your sensor datasheet:

1) what voltage level your sensor provides for logic '1'? I assume '0' is close enough to 0V.

2) what is the threshold voltage on data going to the sensor? I.e. when it switches from sensing logical '0' to logical '1'

Speaking on setting I/O standard per pin - you do not use VHDL (or Verilog) to assign pin settings with Altera, you use .qsf file for that, which can be modified via Quartus -> Assignments -> Pin Planner dialog window.

V.L.