Reloadable Coefficient Filters Fail for Some MCV Filters

Description

Some reloadable coefficient filters with multicycle variable architecture do not produce the right output when a new set of coefficients is reloaded.

This error is observed in some of the reloadable coefficient MCV filters.

The produced output does not match the expected output when the new coefficient set is reloaded.

Resolution

There are two separate problems which may cause this failure. If your target device is Cyclone III, change the device to Stratix II or Stratix III in the FIR Compiler GUI and regenerate the filter. (Your device selection in the Quartus II project should stay the same). If the coefficient storage is set to logic cells, change to a block memory (such as M512, M9K, or Auto).