Chapter 1: Hardware Design Using System Generator
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.
82
www.xilinx.com
System Generator for DSP User Guide
UG640 (v11.4) December 2, 2009
Configurable Subsystems and System Generator
•
Drag a template block into the library. (Templates can be found in the Simulink library browser under Simulink/Ports & Subsystems/Configurable Subsystem.)
•
Rename the template block if desired.
•
Save the library.
•
Double click to open the template for the library.
•
In the template GUI, turn on each checkbox corresponding to a block that should be an implementation.
•
Press OK, and then save the library again.
System Generator for DSP User Guide
UG640 (v11.4) December 2, 2009 www.xilinx.com
83
