The project1.out application, created in the previous tutorial, is now ready to be run in C-SPY where you can watch variables, set breakpoints, view code in disassembly mode, monitor registers and memory, and print the program output in the Terminal I/O window, etc.

In the IDE, you can dock windows at specific places, and organize them in tab groups. You can also make a window floating, which means it is always on top of other windows. If you change the size or position of a floating window, other currently open windows are not affected.

The status bar, located at the bottom of the the IAR Embedded Workbench® IDE main window, contains useful help about how to arrange windows. For further details, see the IDE Project Management and Building Guide for ARM®.

Make sure the following windows and window contents are open and visible on the screen: the Workspace window with the active build configuration tutorials – project1, the editor window with the source files Tutor.c and Utilities.c, and the Debug Log window.

Alternatively, click the Step Over button on the toolbar.

Step until the call to the InitFib function.

Alternatively, click the Step Into button on the toolbar.

At source level, the Step Over and Step Into commands allow you to execute your application a statement at a time. Step Into continues stepping inside function or subroutine calls, whereas Step Over executes each function call in a single step. For further details, see the C-SPY® Debugging Guide for ARM®.

When Step Into is executed you will notice that the active window changes to Utilities.c as the function InitFib is located in this file.

You can also step on a statement level. Choose Debug>Next statement to execute one statement at a time. Alternatively, click the Next statement button on the toolbar.

Notice how this command differs from the Step Over and the Step Into commands.

C-SPY allows you to watch variables or expressions in the source code, so that you can keep track of their values as you execute your application. You can look at a variable in several ways. For example, point at it in the source window with the mouse pointer, or open one of the Auto, Locals, Live Watch, Statics, or Watch windows. In this tutorial, we will look into some of these methods.For more information about inspecting variables, see the C-SPY® Debugging Guide for ARM®.

The Watch window will show the current value of i and Fib. You can expand the Fib array to watch it in more detail.

C-SPY contains a powerful breakpoint system with many features. For detailed information about breakpoints, see the C-SPY® Debugging Guide for ARM®.

The most convenient way is usually to set breakpoints interactively, simply by positioning the insertion point in or near a statement and then choosing the Toggle Breakpoint command.

Alternatively, click the Toggle Breakpoint button on the toolbar.

A breakpoint will be set at this function call. The function call will be highlighted and there will be a red dot in the margin to show that there is a breakpoint there.

To view all defined breakpoints, choose View>Breakpoints to open the Breakpoints window. You can find information about the breakpoint execution in the Debug Log window.

Alternatively, click the Go button on the toolbar.

The application will execute up to the breakpoint you have set. The Watch window will display the value of the Fib expression and the Debug Log window will contain information about the breakpoint.

Debugging with C-SPY is usually quicker and more straightforward in C/C++ source mode. However, if you want to have full control over low-level routines, you can debug in disassembly mode where each step corresponds to one assembler instruction. C-SPY lets you switch freely between the two modes.

To view code coverage information, right-click in the Disassembly window and choose Code Coverage>Enable and then Code Coverage>Show from the context menu.

Try the step commands also in the Disassembly window and note the code coverage information indicated by green diamonds.

The Memory window lets you monitor selected areas of memory. In the following example, the memory corresponding to the array Fib will be monitored.

The memory contents in the Memory window corresponding to Fib will be selected.

If not all of the memory units have been initialized by the InitFib function of the C application yet, continue to step over and you will notice how the memory contents are updated.

To change the memory contents, edit the values in the Memory window. Just place the insertion point at the memory content that you want to edit and type the desired value.

Sometimes you might have to debug constructions in your application that make use of stdin and stdout without the possibility of having hardware support. C-SPY lets you simulate stdin and stdout by using the Terminal I/O window.

Alternatively, click the Go button on the toolbar.

As no more breakpoints are encountered, C-SPY reaches the end of the application and a Program exit reached message is printed in the Debug Log window.

If you want to start again with the existing application, choose Debug>Reset, or click the Reset button on the toolbar.

C-SPY also provides many other debugging facilities. Some of these—for example macros and interrupt simulation—are described in the following tutorials.

For further details about how to use C-SPY, see the C-SPY® Debugging Guide for ARM®.