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Chapter 9
Building Targets

Overview

A target is a program that executes a Stateflow model or a Simulink model containing a Stateflow state machine. Stateflow and companion tools can build targets for virtually any computer.

Target Types

Simulink and its companion tools can build the following types of targets:

Building a Target

Building a target involves the following steps:

   1.
Configure the target.
See "Configuring a Target" for more information. You need to perform this step only if you are building a stand-alone or RTW target or are including custom code in the target (see "Building Custom Code into the Target" on page 9-3).
   2.
Start the build process.
Stateflow automatically builds or rebuilds simulation targets, when you initiate simulation of a state machine. You must explicitly initiate the build process for other types of targets. See "Starting a Build" for more information.
Configuring and building a target requires a basic understanding of how Stateflow builds targets, in the case of simulation and stand-alone targets, and how Real-Time Workshop builds targets, in the case of RTW targets. See "How Stateflow Builds Targets" for information on how Stateflow builds targets. Real-Time Workshop uses basically the same process for building targets that contain state machines as it uses for building targets that do not. See the Real-Time Workshop User's Guide for information on how Real-Time Workshop builds targets.

Rebuilding a Target

You can rebuild a target at any time by repeating step 2. When rebuilding a target, Stateflow rebuilds only those parts corresponding to charts that have changed logically since the last build. When rebuilding a target, you need to perform step 1 only if you want to change the target's custom code or configuration.

Building Custom Code into the Target

You can configure the target build process to include to build custom code, that is, C code supplied by you, into the target (see "Specifying Custom Code Options"). This capability facilitates creation of applications that integrate Stateflow state machines. In particular, it allows you to use Stateflow or Real-Time Workshop to build the entire application, including both the portions that you supply and the state machine target code generated by Stateflow (or by Real-Time Workshop and Stateflow, when building applications that include other types of Simulink blocks).

How Stateflow Builds Targets

Stateflow builds a target for a particular state machine as follows. It begins by parsing the charts that represent the state machine to ensure that the machine's logic is valid. If any errors occur, Stateflow displays the errors in the MATLAB command window (see "Parsing") and halts.

If the charts parse, Stateflow next invokes a code generator to convert the state machine into C source code. The code generator is a MATLAB M-file, named sfc.m, that translates a Stateflow state diagram into an equivalent C source code representation. The code generator accepts various command-line options that control the code generation process. You can specify these options via the Stateflow user interface (see "Adding a Target to a State Machine's Target List").

In the case of stand-alone targets, the code generator optionally generates a main program that exercises each of the state machine's charts. If you do not select this option, you must provide the main program for the stand-alone target. See "Creating a Target Main Program" for more information. (Simulink serves as the main program for a simulation target. Hence, you do not need to provide a main program for a simulation target.)

The code generator also generates a makefile to build the generated source code into an executable program. The generated makefile can optionally build custom code that you specify into the target (see "Specifying Custom Code Options").

Finally Stateflow builds the target, using a C compiler and make utility that you specify (see "Setting Up Target Build Tools" for more information).


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