User guide

38 www.xilinx.com System Generator for DSP User Guide
UG640 (v 12.2) July 23, 2010
Chapter 1: Hardware Design Using System Generator
As shown below, in the parameter editing dialog for the accumulator and multiplier
blocks, there are radio buttons that allow either the truncate or round option to be selected.
In order to use a parameter rather than the radio button selection, right click on the radio
button and select: “Define With Expression”. A MATLAB expression can then be used as
the parameter setting. In the example below, the trunc_round parameter from the
subsystem mask can be used in both the accumulator and multiply blocks so that each
block will use the same setting from the mask variable on the subsystem.