The floppies which accompany this note contain a link to connect an Altia Design interface to BetterState generated state machine code. BetterState is a state machine design tool with code generation capabilities for C, C++, VHDL, Verilog HDL, and other languages. Altia Design is software for quickly creating interactive, dynamic graphical representations of product user interfaces. By combining the Altia interface and the BetterState state-machine logic of a system, functional computer-based prototypes of embedded products can be quickly created, tested, and modified, helping verify product requirements early in the design process.

The fundamental concept of state-machine programming is that a system will transition from one state to another based on the occurrence of specific events. Events, which are simply variables whose values have changed, are evaluated by the state-machine to determine if a transition should be made to another state. When a state is entered, the system is told what to do. If you think of a flashlight as a state machine, turning the switch on will take you to the "on" state, and the light will go on. Turning the switch off will take you to the "off" state, and the light will go off.

With the Altia-BetterState link, an Altia interface becomes the mechanism to provide events and display results of a BetterState state-machine. In the above example, Altia would represent both the switch and the light while the BetterState state-machine would determine what to do with the light based on switch events. An Altia interface is an easy to understand and use representation of the system’s real user interface. Developers use this interface to test and demonstrate product requirements, such as usability and features, to parties not involved in the day-to-day development. Developers, project managers, customers, and others can verify and modify the product’s requirements early in the development cycle.

To link the two products, Altia provides a 32 bit Microsoft library and header file (absdde.lib and altiabs.h) for C and C++ that are linked directly into a program with the compiled source code generated by BetterState.

The altiabs.h header file references functions for the BetterState developer to place in the state and transition code dialogue boxes of their state machines. These functions take care of checking with an Altia interface to either verify that a variable has had an event happen to it, to check a variable’s value , or to send a value or event to the Altia interface. Based on the results of these functions, the BetterState developer can determine how they would like to transition from one state to the next.

• The Altia interface contains the various buttons, switches, displays, and other graphical objects which will control and display the actions of the state-machine. The names and values of the objects in the Altia interface will be referenced in the state-machine.

• The BetterState state-machine(s) are constructed in the BetterState editor, using the functions referenced in the altiabs.h header file in the Transition and State code dialogue boxes. Transitions from one state to another are based on an event from the Altia interface. Actions taken in a state may check on or send values to the Altia interface.

Microsoft 32-bit C/C++ compiler

Altia Design editor or runtime license and design file.

BetterState development license.

Typical usage is in a Transition Code Dialogue's Condition field, e.g.

If the event "push", with a value of 1 is coming from the Altia interface, then the state-machine code will make that transition.

Typical usage is in a State/Place Code Dialogue box's Action field, e.g.

if ( strcmp( getText("message_text"), "start") == 0)

start_function();

else

stop_function();

if ( getValue("power_switch") == 1)

setValue("power_light", 1);

Typical usage is for sending string messages to Altia. Often used in State/Place Code Dialogue box's Action field. e.g.

if ( getValue("power_switch") == 1)

setText("message_text", "Powering up!");

else

setText("message_text", "Powering down!");

Create a BetterState state-machine to represent your system using the above functions in the state Action and Transition code dialogue boxes.

Use the BetterState Code Generator to create the source code for your state-machine(s). In the BetterState code generation options page, choose the "Misc" tab and type the following in the "header files to include" field:

#include "altiabs.h"

Copy the files absdde.lib and altiabs.h to the directory of your choice (perhaps \usr\altia\lib\ms32 or \bstate41\dlls\lib\lib32) and make sure that your compiler can search these directories at compile time.

In the Microsoft Visual C/C++ development environment, create a new project workspace and choose to create a console application. Add the following files to the projects:

yourstate.c /* the source code of your state-machine(s) generated from BetterState */

Create and add the following file to your project:

main.c /* a main loop program */

Use the following as a guide for creating your main.c program. You may wish to use it directly.

/* Typical main() routine linking Altia and BetterState */

#include <stdio.h>

#include "altiabs.h"

/* include the header for the absdde.lib */

extern int CHRT_test();

/* Declare C function generated from BetterState file */

void main( argv, argc)

int argv;

char *argc[];

{

while ( updateIO("myfile.dsn",NULL,NULL) != -1 )

/* As long as we receive events from the Altia interface*/

{

CHRT_test(0);

} /* end while */

} /* end main() */

You are ready to compile and run the system. It is recommended that you study the enclosed test2.dsd and test.dsn for an example of a working project. Source files for main.c and test.c (the code generated by BetterState) are included.