General Description: It is not unusual for CORE Generator modules to contain MUXCY symbols with no output signal attached. Normally, the MUXCY is trimmed with no problems; however, if a user finds it necessary to run MAP with trimming disabled because the design is incomplete, MAP can fail with the error:
"ERROR:MapLib:487 - COUT pin of MUXCY symbol "xlxi_1/BU287" (output signal=<none>) is not connected to a signal. This will cause problem with downstream tools. If '-u' behavior is intended, you should attach a signal to the output of MUXCY so that it can be programmed properly."
The following environment variable work-around is available in 4.1i MAP; it instructs MAP to handle this special-case trimming issue appropriately:
For PCs: SET XIL_MAP_BETTER_U=1
For Workstations: setenv XIL_MAP_BETTER_U 1
This option becomes the default trimming setting for 6.1i.