Description
When using ALTASMI_PARALLEL in Cyclone® III or Cyclone IV devices, the Quartus® II software enforces a 2.5V I/O constraint on the AS interface I/O pins, so you may get a fitter error if this does not match the VCCIO setting for the bank that contains the AS pins in your design.
Resolution
There are two possible workarounds:
Workaround 1
Go to the Assignments menu and select Device
Click on Device and Pin options
Click on Voltage under the Category selection
Change the default from 2.5V to the voltage of the bank that contains the AS signals. (Note this setting will apply to any I/O you have which does not already have an I/O standard assignment).
Workaround 2
Make I/O standard assignments to all the pins that are mentioned in the error message, so that they meet your design VCCIO requirements for the bank that contains the AS pins.
An example is shown below.
set_instance_assignment -name IO_STANDARD "3.3-V LVTTL" -to "top_altasmi_parallel_l852:top_altasmi_parallel_l852_component|cycloneii_asmiblock2~ALTERA_DCLK"
