When I run MAP on my design with FIFO Generator Core v1.1, the following error message occurs:
"ERROR:LIT - The attribute ALMOST_FULL_OFFSET and/or ALMOST_EMPTY_OFFSET
setting for instance u0/BU2/U0_fblk_inst_few_inst_fed1_inst_fifoprim_sngfifo (of type FIFO16) is not valid."
This error occurs using FIFO Generator v1.1 with the ISE 6.3i Service Pack 1 (SP1) or Service Pack 2 (SP2) software. The error is caused by new DRC (Design Rule Check) introduced in the software starting with ISE 6.3i SP1. You can prevent this error by using ISE 6.3i without any Service Packs.
FIFO Generator v2.0 Core will include Programmable Full and Programmable Empty flags that will eliminate this error. FIFO Generator v2.0 will be released with IP Update 4 in November 2004.