General Description: In Foundation Express 2.1.2. If you try and synthesize an HDL file that is older than the std_logic_1164 library, you will get the following message:
The entity depends on the package std_logic_1164 which has been analyzed more recently. Please reanalyze this source file and try again. LBR-28.
One solution to this problem is to check your system date/time. If the date on your PC is earlier than the compile date/time of the IEEE libraries, then you will not be able to synthesize.
Workaround: 1. Change the system date/time so that it shows the correct date/time. 2. Open the HDL source file(s) with the HDL editor. 3. Re-save the file(s) to update the date/time stamp. 4. Re-analyze the source file(s). 5. Re-synthesize the design.