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AR# 4869

NGD2VER/NGD2VHDL 1.5: The connection from RAM to LUT are optimized away.


Keywords: Virtex, ngd2ver, ngd2vhdl

Urgency: Standard

Signals going from block RAM to LUTs, present in the NCD file are no longer
present after running Ngd2ver/Ngd2vhdl.


Fixed in A1.5.25.

The problem is in ngd_prep and is exposed when a block RAM output signal
drives a LUT (ROM) input. A function is called on every ROM input pin's signal.
This function is supposed to remove the signal only if it has no driver, but the
block RAM output is not detected as a driver (since it is not an NGD primitive).
Further, this trimming is only supposed to be called when processing an .ngd file
(not an .nga file), but the call for ROMs is made on both file types.
AR# 4869
Date 05/30/2000
Status Archive
Type ??????