My schematic design is opened within pld_da, which was created using Xilinx A1.5i, and now I am using 2.1i. When I run Check Design, an error similiar to the following occurs:
"Error: Out of date reference; Version 1 of symbol "gnd" is not the most current (2) for instance: I$3 Error: Out of date reference; Version 1 of symbol "vcc" is not the most current (2) for instance: I$5"
In the A1.5i library the vcc and gnd symbol pin names were vcc and gnd, but now in 2.1i, the pin names have changed to P and G. So the schematic sheets that contain any vcc or gnd components must be updated by performing the following from within pld_da:
1. Right-click in the pld_da session window (the window behind the schematic, if the schematic is opened). You might have to resize or minimize the schematic window.
2. Choose the Update Design option.
3. Either enter in the top level name in the "Enter Top level design name" dialog box, or use the "Navigator" button to select it.
4. Click on the "OK" button to proceed with updating the design.
5. Check the design. It should now finish without errors.