AR# 7728: 2.1i Virtex Map - The default input path delay element usage is being changed.
AR# 7728
2.1i Virtex Map - The default input path delay element usage is being changed.
描述
Keywords: Delay, input path, default
Urgancy: Standard
General Description: 1.5i had defaults of NODELAY for the "I" path out of IOBs, and DELAY for data paths feeding the input FF inside the IOB. 2.1i automatically inserts DELAY for both paths. General FAE and expert user consensus is that we should revert back to the 1.5i default. Also, if DLL drives clock on FF inside IOB, NODELAY should be the proper default.