Understanding Data Watchpoints in Embedded Debugging

In embedded systems debugging, Data Watchpoints are a powerful tool for tracking variable modifications in real-time. They help identify who or what is changing a variable's value, which is crucial in large projects where multiple developers are involved.

What is a Data Watchpoint?

A Data Watchpoint is a type of breakpoint that triggers when a specific memory location (variable or address) is modified. It is particularly useful when debugging unexpected variable corruption due to:

?? External modifications by another module or developer

?? Stack overflow or memory corruption

?? Pointer mismanagement

Example Scenario

Let’s consider a global variable:

int x = 10;
        

If x is modified in a function, say fun(), we need to determine which line of code changes it. Instead of manually tracing, we can set up a watchpoint on x variable and let the debugger detect the modification automatically.

How to Set Up a Data Watchpoint?

1?? Put the board in debug mode.

2?? Go to Show View → Breakpoints.

3?? Click Add Watchpoint and enter x variable.

4?? Select Write (to detect modifications).

5?? Click Apply & Close.

Now, when execution reaches the line modifying x, the debugger halts at that exact instruction.

Watching Memory Addresses

You can also watch a memory address instead of a variable:

1?? Find the address of someData using &x.

2?? Add a watchpoint for this address in the Breakpoints tab.

3?? Set it to trigger on Write operations.

This ensures the execution stops whenever the memory location is modified, helping track unexpected changes in pointer values or global data.

?? Why Use Data Watchpoints?

?? Easily trace which parts of the code are modifying a variable.

?? Debug issues caused by stack overflow or memory corruption.

?? Pinpoint unintended modifications in large projects.

?? Improve overall debugging efficiency and code reliability.