This tutorial is designed to introduce you to key features of Tornado using the integrated VxWorks target simulator. It does not require any target hardware or special configuration of your host system. It is not a programming tutorial; the sample program was written to exercise Tornado in illustrative ways.
While simply reading the tutorial may be edifying, we encourage you to perform the steps described in this chapter so that you can experience Tornado first hand. In the course of the tutorial, you will:
Naturally, you will have several opportunities to modify the program to correct its runtime behavior, rebuild it, download it, and run it again.
The tutorial assumes minimal knowledge of multi-threaded programming in C, and basic Windows usage.
You might approach the tutorial with the following scenario in mind:
A colleague has abruptly announced that he is going on vacation, and the VP of Engineering has handed you the delinquent's portion of The Project. You are alarmed. His code is typically cryptic, poorly documented, and full of run-time mischief. The thought of reading his source gives you a headache. And the target hardware seems to have gone on vacation with him. You decide to use Tornado's target simulator and analytical tools to see how the code behaves...
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To start Tornado, select Start>Programs>Tornado2.2>Tornado (with a default installation), or select the Tornado desktop shortcut (if you have created one).
If Tornado is unable to connect to a Tornado registry, you will be prompted to start one. See Step 10: Set Up the Tornado Registry for information about registry configuration options at installation. You can start a registry manually by selecting the Tornado Registry option from the Tornado program group menu.
The main Tornado window appears with the Create Project dialog box open by default:
You can use the toolbars as floating palettes or dock them on the sides, top, or bottom of the main Tornado window.
If the Create Project in New/Existing Workspace dialog box is not displayed, click File>New Project.
Then select the option for a downloadable application:
The Tornado application wizard appears. This wizard guides you through the steps of creating a new project. In the first step, the wizard prompts you for:
A project consists of the source code files, build settings, and binaries that are used to create an application.
A workspace is simply a grouping of one or more projects, which provides a useful means of working with related material, sharing code between projects, and associating related applications. Once a project and workspace have been created, a workspace window displays information about the projects that it contains.
You can accept the wizard's defaults for the project and workspace, but it is preferable to set them up outside of the Tornado installation tree. (If you do so, you won't have to untangle your work from the Tornado tree when you upgrade Tornado.)
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In the second wizard dialog, you identify the toolchain with which the downloadable application will be built.
A toolchain is a set of cross-development tools used to build applications for a specific target processor (preprocessor, compiler, assembler, and linker).
The default toolchain names for target simulators take the form SIMhostOsgnu (for example, SIMNTgnu).
Select A toolchain and the option for the target simulator from the drop-down list, as illustrated below:
The final wizard dialog confirms your selections:
The Workspace window appears. The workspace window title includes the name of the workspace, and the window itself includes a folder for the project:
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The sample program for this tutorial is cobble.c. It is a simple multi-tasking application that simulates a data collection system in which data is retrieved from an external source (for example, a device that generates interrupts as data comes in). The four cobble tasks are:
The cobble program also includes the progStart( ) and progStop( ) routines. Later in the tutorial, you will use these routines to start and stop the program.
Before you add the sample program to the project, copy it from the Tornado installation tree to another location, such as the project directory you have set up with the Tornado project wizard.
The sample file cobble.c is located in installDir\target\src\demo\start.
In the examples provided thus far in the tutorial, c:\projects has been used as the base directory for our project work, and subsequent examples are based on cobble.c being copied to that directory.
After you have copied cobble.c to another location, add it to the project. Select Add Files from the context menu in the File view of the workspace:
Then use the file browser that appears to select cobble.c.
Open the Object Modules folder in the Files view so you can see the names of the object files that are built from the project:
The Tornado project facility automatically creates the file projectName.out as a single, partially linked module when a project is built. It comprises all of the individual object modules in a downloadable application project, and provides for downloading them all to the target simultaneously.
To review the default build settings defined when you created the project, select the Builds tab on the Workspace window, open the gizmo Builds folder, and double-click on the default build name (for example, SIMNTgnu).
The properties sheet for the build appears, which you can use to review makefile rules and macros, as well as the compiler, assembler, and linker options used for the build.
When you display the C/C++ compiler page, you will note that the Include debug info checkbox is selected by default. This selection ensures that optimization is turned off when the project is compiled with debug information:
Close the property sheet by clicking on the Cancel button.
Build the project by selecting Build 'gizmo.out' from the context menu:
The option Build 'projectName.out' builds all project modules as a single, partially linked module that is optimal for downloading to a target.
Before Tornado builds the project, the Dependencies dialog box warns you that makefile dependencies have not been calculated for cobble.c:
Tornado calculates makefile dependencies and proceeds with building the project. If any external dependencies are found, they are automatically included in the project and listed in the External Dependencies folder in the Files view of the workspace.
The build output window displays any errors and warnings. In this case, there are none:
You can download your project from the Files view of the workspace, and start the integrated simulator, all as part of the same process.
First display the Files view of the workspace window.
Then select the project folder name with the right mouse button and select the Download 'gizmo.out' option from the context menu:
Tornado prompts you to start a simulator:
Leave Standard Simulator selected, and click OK to continue.
The target simulator window opens, and Tornado prompts you to start a target server. Click OK in the VxSim-Lite Launch dialog to continue:
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A target server manages all communication between Tornado host tools, such as the debugger, and the target. The convention for target server names is targetName@hostName. In this example, the name of the target is vxsim (the default for the integrated simulator), and the name of the PC host is ala-tau.
The name of the target server is displayed in the Tornado launch toolbar:
The toolbar includes buttons for starting Tornado tools such as the browser, shell, and debugger. The buttons are activated when the target server is started.
Before you run an application, it is often useful to configure and start the Tornado debugger, so that the debugger can respond automatically to any program exception.
The Tornado debugger (CrossWind) combines the best features of graphical and command-line debugging interfaces. The most common debugging activities, such as setting breakpoints and controlling program execution, are available through convenient point-and-click interfaces. Similarly, program listings and data-inspection windows provide an immediate visual context for the crucial portions of your application.
To configure the debugger, select Tools>Options>Debugger from the main Tornado window. When the Options dialog appears, select Always under Auto attach to tasks, so that the debugger will automatically attach to a task when an exception occurs:
Click OK to continue. For more information, see the Tornado User's Guide: Debugger.
To start the debugger, use the debugger button
in the Tornado launch toolbar. The back trace and variables windows open (you may close them), and the status line at the bottom of the main Tornado window announces that the debugger is running:
The Tornado shell (also known as WindSh) is a C-language command interpreter that allows you to invoke any routine from the shell command line that has been downloaded to the target. The shell also includes its own set of commands for managing tasks, accessing system information, debugging, and so on.
You can run the program from the shell command line. To start a shell, click the shell button
.
When the shell window opens, run the program by entering the name of the main routine, progStart, at the command line:
The Tornado browser is a system-object viewer that is a graphical companion to the Tornado shell. The browser provides display facilities to monitor the state of the target system, including summaries of active tasks, memory allocation, and so on.
To start the browser, click the browser button
in the Tornado launch toolbar.
When the browser appears, Select Memory Usage from the drop down list and click the periodic refresh button
. This will update the display every few seconds, and you will note that cobble.c has a voracious appetite for memory:
WindView is the Tornado logic analyzer for real-time applications. It is a dynamic visualization tool that provides information about context switches, and the events that lead to them, as well as information about instrumented objects such as semaphores, message queues, and watchdog timers.
Click the WindView button
in the Tornado launch toolbar to display the WindView Control window. The WindView Collection Configuration dialog box also appears. Select Additional Instrumentation from the drop-down list and click OK:
To begin data collection, click the GO button
in the WindView Control window.
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Wait a few seconds, and then click the update button
in the WindView Control window to update the status of data collection:
When the Buffers value listed under Current Content reaches at least two, click the Stop button
to end data collection.
You may notice a certain sluggishness in your machine's performance, which is due to the sample program's runtime misbehavior on the integrated simulator.
Before you upload the WindView data from the simulator target to the host, stop the sample program by entering progStop at the shell command line.
Then use the upload button
to upload the data. A view graph is displayed while the data is uploaded.
When you maximize the view graph window, the data display should look something like the following:1
You can use the zoom buttons
on the WindView toolbar to enlarge or decrease the size of the scope of the display, and scroll bar at the bottom of the view graph to display the rest of the data. (The zoom 100% button
displays all of the data at once.) The flag-shaped icons indicate semaphore gives and takes. The horizontal lines indicate task states (executing, pending, ready, and so on). For information about the meaning of the WindView icons, select Help>WindView Help>Legend.
Note that tCrunch, the task that processes data and removes nodes from a linked list, never runs.
Close the view graph and click No in response to the dialog that prompts you to save the data with: Save changes to hostName?
Open the source code in the editor by double-clicking on cobble.c in the workspace Files view. Then find the progStart( ) routine, where you'll discover that tCrunch is assigned a lower priority (240) than tMonitor (230), which never allows it to run. As a consequence, data is never processed, and nodes are never deleted from the linked list.
Edit the source file to reverse the priorities between the two tasks:
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Start the program again from the Tornado shell with the command progStart.
Both the simulator and shell windows soon announce an exception and the number of the task in which it occurred:
In addition, the debugger opens the editor window automatically with a context pointer marking the position in the crunch( ) routine where the error was generated:
Before you proceed, reboot the target simulator: in the shell window, press RETURN to display the prompt, and enter reboot.
A message box announces that the target connection has been lost, and that the debugger is being stopped. Click OK.
If you use the i command in the shell window after you have rebooted the simulator, you see that only VxWorks system tasks are now running:
Open the cobble.c file in your editor by double-clicking on the file name in the Files view of the workspace window. Fix the source of the exception error in the crunch( ) routine by using the commented code immediately below the division operation--or something more interesting. Save the file and close the Source view window.
Then use the context menu in the Files view of the workspace to select the ReBuild All (gizmo.out) option. When the build is done, close the Build Output window.
Download the application to the target with the Download 'gizmo.out' option from the context menu.
To be sure that everything is working, start the debugger with the debugger button
.
Start the program again from the Tornado shell with the command progStart.
Click on the Windview button
to display the WindView Control window. Then click the GO button
in the WindView Control window to begin data collection.
Wait a few seconds, and click the update button
in the WindView Control window to update the status of data collection.
When the Buffers value listed under Current Content reaches at least two, click the Stop button
to end data collection.
Then use the upload button
to upload the data. A view graph is displayed while the data is uploaded.
Maximize the view graph window and scroll through the WindView data. You should find that all tasks, including tCrunch, are running in an orderly manner, and the view graph data should look like the following:
You can check memory consumption once again with the browser by clicking the browser button
in the Tornado launch toolbar.
When the browser appears, select Memory Usage from the drop-down list and click the browser's periodic refresh button
. Every few seconds the display will be updated.
Notice that memory consumption fluctuates modestly within a constant range:
Moreover, output in the simulator window indicates that the program is humming along nicely, providing you with information about when it's hot and when it's not:
Stop the program by entering progStop at the shell command line.
For detailed information about using features of the Tornado IDE such as the project facility, shell, browser, and debugger, see the Tornado User's Guide. The guide also provides information about setting up your Tornado development environment with target hardware.
For information about VxWorks itself, see the VxWorks Programmer's Guide, the Network Programmer's Guide, and the VxWorks API Reference.
The Tornado documentation set is available online in HTML format from the main Tornado menu Help>Manuals Contents, or directly from the top level HTML file installDir\tornado\docs\books.html.
1: The color of the view graph display can be changed with Tools>WindView>Options.