User guide

System Generator for DSP User Guide www.xilinx.com 83

UG640 (v 12.2) July 23, 2010

Configurable Subsystems and System Generator

A configurable subsystem is a kind of block that is made available as a standard part of

Simulink. In effect, a configurable subsystem is a block for which you can specify several

underlying blocks. Each underlying block is a possible implementation, and you are free to

choose which implementation to use. In System Generator you might, for example, specify

a general-purpose FIR filter as a configurable subsystem whose underlying blocks are

specific FIR filters. Some of the underlying filters might be fast but require much hardware,

while others are slow but require less hardware. Switching the choice of the underlying

filter allows you to perform experiments that trade hardware cost against speed.

Defining a Configurable Subsystem

A configurable subsystem is defined by creating a Simulink library. The underlying blocks

that implement a configurable subsystem are organized in this library. To create such a

library, do the following:

• Make a new empty library.

• Add the underlying blocks to the library.