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AR# 20572

LogiCORE MAC FIR v5.0 - Why does the Interpolation MAC FIR's behavioral simulation fail with block RAM address errors, "Warning: NUMERIC_STD.TO_UNSIGNED: vector truncated" or "Warning: Undefined input ADDRB. Setting output DOUTB to X"?

Description

Keywords: LogiCORE, MACC, MAC, FIR, behavioral, interpolation, simulation, BRAM, error

Why does the Interpolation MACC FIR's behavioral simulation fail with block RAM address errors, "Warning: NUMERIC_STD.TO_UNSIGNED: vector truncated" or "Warning: Undefined input ADDRB. Setting output DOUTB to X"?

e.g.
# ** Warning: NUMERIC_STD.TO_UNSIGNED: vector truncated
# Time: 0 ps Iteration: 0 Instance: /mac_fir_interpolate_tb_nty/mac_fir/bu330/a0
# ** Warning: NUMERIC_STD.TO_UNSIGNED: vector truncated
# Time: 0 ps Iteration: 0 Instance: /mac_fir_interpolate_tb_nty/mac_fir/bu304/a0
...
# ** Warning: Undefined input ADDRB. Setting output DOUTB to X
# Time: 87500 ps Iteration: 4 Instance: /mac_fir_interpolate_tb_nty/mac_fir/bu324
# ** Warning: Undefined input ADDRB. Setting output DOUTB to X
# Time: 100 ns Iteration: 4 Instance: /mac_fir_interpolate_tb_nty/mac_fir/bu324

Solution

The above errors will occur only during behavioral simulation, if the clock starts with a rising edge at time zero (0ns).

To solve this problem, you should change the clock so that a rising transition does not occur at time zero.
AR# 20572
Date Created 09/03/2007
Last Updated 04/01/2009
Status Archive
Type General Article