User manual

Basic debugging features UM0036
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5.9 Data breakpoints
Note: Data breakpoints are not available on the STVD EMU3 version. However, the equivalent
functionality is provided using Advanced Breakpoints (see Section 10.2: Using advanced
breakpoints on page 291).
While instruction breakpoints allow you to stop the running of the application at a specific
instruction line, data breakpoints interrupt the run when a data variable is either read or
written.
Each data variable has a fixed address, and by placing a data breakpoint on a particular
variable, you can effectively interrupt the program when that address is either read or written
to.
Note: For the Simulator and DVP versions of STVD, there are two types of data breakpoint: a
read data breakpoint which stops the program when the flagged variable is read, and a write
data breakpoint, which stops the program when the flagged variable is written.
This section provides information about using data breakpoints, including:
● Inserting data breakpoints
● Using the Data Breakpoints window
5.9.1 Inserting data breakpoints
To insert a data breakpoint:
1. In the Editor, select a variable in the source code file. Be sure to select the entire
variable name (highlight it with the mouse).
2. While the variable is selected, you may either:
– Right-click the mouse. A contextual pop-up menu will appear as shown in
Figure 131. Select either Insert Read Data Breakpoint or Insert Change Data
Breakpoint from the contextual menu. For EMU2 emulators only Insert Change
Data Breakpoint is available in the contextual menu.
In the example shown in Figure 131, we are inserting a data breakpoint for the
variable nbOfTransitions++.
– or Insert a data breakpoint by dragging and dropping the selected variable into the
Data Breakpoints window (described in Section 5.9.2: Using the Data
Breakpoints window).