How do I assign device specific pin numbers to the I/O ports using the block diagram editor? I want the pin numbers to show-up on my schematics.
In order for it to work, you need to add attribute declarations (in addition to attribute specification) to the block diagram.
Please follow these steps:
Select Diagram | VHDL | Declaration for an Entity from the main menu (there is a button on the toolbar as well). Place the Entity Declaration anywhere on the diagram.
Inside the Entity Declaration type: attribute LOC: string;
Save the file and compile it. The errors should disappear.
NOTES: This solution is supported by the Xilinx and Lattice vendors.