Category: Specifications
Tools: Quartus® Prime / Quartus II
Device: Cyclone® V


To enable both Input Register and Output Register for a bidirectional pin, set it in the Assignment Editor or Pin Planner and compile.

Select Assignments menu ⇒ Assignment Editor to launch the Assignment Editor. Then set as follows:

<Input direction>
To: bidirectional pin
Assignment Name: Fast Input Register
Value: On

<Output direction>
To: bidirectional pin
Assignment Name: Fast Output Register
Value: On

To check whether the settings have been reflected, check that Input Register and Output Register of the corresponding pin are set to Yes in Fitter ⇒ Resource Section ⇒ Bidir Pins in the compilation report.