AR# 3493: 2.1i, V1.5, V1.4 COREGEN, XC4000: Incorrect data on output of 4K PDA FIR and SDA FIR cores when maximum output width is not selected
AR# 3493
2.1i, V1.5, V1.4 COREGEN, XC4000: Incorrect data on output of 4K PDA FIR and SDA FIR cores when maximum output width is not selected
Description
Keywords: PDA, SDA, FIR, output width
Urgency: hot
General Description: If the maximum output data width is not selected for the 4K SDA and PDA FIR filter cores, the LSB's of the output are trimmed, and the result is that the user will not see what they expect for output data during simulation.
The trimming of the LSB's is inconsistent with how data bits are trimmed in packages like Matlab and Elanix.
This is a known bug (CR 103333).
解决方案
This problem has been fixed in the v1.4.1 patch available on the CORELINX web page,
If you are unable to access this patch, the workaround is as follows:
Select the maximum output width from the choices given to you by the PDA or SDA FIR implementation pop-up window after you have indicated the number of taps.
If you do not need all of the output bits, simply leave them unconnected in your design, and they will be trimmed later when the design is processed by Map.