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Appendix B: Debug your project in VSCode

Purpose​

Explore options for debugging a target within a compiled application.

Overview​

Debugging is an important tool for embedded development. Zephyr and VSCode offer several options for connecting a debugger to the target to see code flow and interrogate variables at different points of your project's operation.

Procedure​

1. These line numbers assume you have just completed Lab 1. If you are at another point in your lab work, please either revert to the end of Lab 1 or adjust line numbers and variables to match your current code state.

2. Ensure that your latest code is compiled and flashed to your board, then launch the debugger:

(.venv) $ cd ~/zephyrproject && west debug

3. After this command completes, the console will leave you in a (gdb) prompt. Depending on your terminal window size, you may need to hit the Return key a few times to reach this prompt. There are several ways to interact with GDB (type help to learn more), but one useful option is to use the Text User Interface:

(gdb) tui enable

4. Add a breakpoint to your GDB session, then continue operation until the breakpoint is hit:

(gdb) break main.c:44
(gdb) continue

5. The device will now run until the breakpoint at main.c line 44 is reached. When operation is broken at that point, view the value of a variable:

(gdb) display led_state
(gdb) c

Observe the displayed value of the variable led_state on subsequent loops of the main loop, and verify that this variable matches the state of LED0 on your board:

GDB TUI view showing source code at breakpoint on main.c line 44 with led_state values displayed

6. Exit GDB and return to your venv command prompt:

(gdb) exit

If prompted, choose y to quit the active session.