Description
You can reserve unused APEX 20K and APEX 20KE I/O pins in the Quartus® II software in one of the following three ways:
- As inputs, tri-stated - The pins are reserved as input pins.
- As outputs, driving ground - The pins are reserved as output pins and drive the ground signal.
- As outputs, driving an unspecified signal - The pins are reserved as output pins and drive any signal.
To specify which option, select the Unused Pins tab in the Device & Pins Option menu (Compile Settings, Chips & Devices tab).
The unused I/O pins on an APEX device should then be connected or left unconnected according to the option that was used. To verify what option was selected when the design was compiled, go to the Device Options section in the compiler settings file (.csf), report file (.rpt), or pin file (.pin) generated by the Quartus software, and look under the Reserve All Unused Pins section.