What are the known issues for System Generator v6.1?
The 2n Tap Linear Phase MAC FIR reference block has a problem in that it is possible for the output binary point to be more than the output data bit width, which throws an error. To avoid this, either the multiplier should be set to full precision or a capability added to determine when the result should be precise or flexible.
The coefficients created are small in nature, so the number of output bits required for the output of the multiplier is 29. Full precision is 33; hence, 4 MSBs are not required. The binary point calculation yields 30, and the error is thrown because of this.
To get around the problem, disconnect the library, then go in and change the multiplier output to "full precision".