I. Introduction
Debugging is a very important part of embedded system development. Debugging helps us locate and fix bugs in the application to ensure the correct operation of the system. In the case of STM32 microcontrollers, we can make use of debugging tools and techniques to improve the efficiency and accuracy of debugging. This article describes how to use the GDB debugger and serial printouts to debug STM32 applications.
2. Debugging tools
Debugging STM32 applications requires the use of specialized tools. Here are a few commonly used debugging tools:
- Built-in debugger: Most STM32 microcontrollers have built-in debug capabilities that provide debug interfaces such as JTAG or SWD. These interfaces can communicate with the debugger software for debugging functionality.
- Emulator/debugger: In order to take advantage of the debugging capabilities of STM32 microcontrollers, an emulator or debugger is usually required. They are connected to STM32 microcontrollers via a debug interface, providing the functionality required by the debugger software.
- IDE (Integrated Development Environment): An IDE is a software tool that integrates development, compilation, debugging, and other functions. For debugging STM32 applications, IDEs like Keil, IAR Embedded Workbench can be used. These IDEs provide a convenient debugging environment through integration with debugger software.
- GDB (GNU Debugger): GDB is an open-source debugger for a wide range of programming languages. For debugging STM32 applications, GDB can be used with the debugger software. GDB supports common debugging operations such as breakpoint setting, variable viewing, and function tracing.
3. GDB debugger
GDB is an open-source debugger that is commonly used for debugging C/C++ programs. For debugging STM32 applications, we can use GDB with the debug interface on the MCU for debugging. Here are some basic steps to debug an STM32 application using GDB:
1. Set up a debugging environment
First of all, you need to prepare a development environment that supports GDB debugging. You can use an integrated development environment (IDE) like Eclipse, Visual Studio Code, etc. Most of these IDEs provide GDB plug-in or integration support for easy debugging.
2. Configure the debugger
Configure the debugger in the IDE to facilitate communication with the STM32 microcontroller. In general, you need to set the debug interface (such as JTAG or SWD) of the MCU, as well as information such as the connection mode and port number.
3. Compile the application
Before debugging, the STM32 application first needs to be compiled. You can use compilers like Keil and GCC to compile the source code into executable files. During the compilation process, you need to enable the generation of debugging information so that GDB can accurately locate and debug the source code.
4. Start a debugging session
Start a debug session in the IDE and connect to the STM32 microcontroller. The IDE will automatically load the executable file and debug information, and connect the GDB to the MCU's debug interface. Once the connection is successful, we can start debugging.
5. Set breakpoints
To locate errors, you can set breakpoints on critical functions or lines of code. Breakpoints will interrupt the execution of the program, allowing us to debug the code one by one and observe the values of variables.
6. Execute the debugging command
Once the program is interrupted at the breakpoint, we can execute various debugging commands to observe and control the execution of the program. For example, you can use the "step" command to execute code line by line, the "print" command to print the value of a variable, the "continue" command to continue executing code until the next breakpoint, and so on.
7. Observe the debugging information
During debugging, the IDE displays debugging information in real time, including the current line of code, the value of variables, and the status of registers. You can analyze and solve problems by looking at this information.
8. End of commissioning
After the debugging is complete, you can choose to continue the program or stop the debugging. Before you stop debugging, you can generate a debug report or save a debug session for future reference.
Fourth, serial port printout
In addition to using the GDB debugger, we can also use the serial printout to debug STM32 applications. Serial port printout is a simple and commonly used debugging method, by sending debugging information to the serial port, we can observe and analyze this information on the PC. Here are some basic steps to debug an STM32 application using serial printout:
1. Configure the serial port
First, a serial interface needs to be configured on the STM32 in order to communicate with the PC. You can choose to use serial communication protocols such as UART or USART, and configure the corresponding parameters such as baud rate, data bits, stop bits, and check bits.
2. Initialize the serial port
In the application, you need to initialize the serial port interface and open the serial port. This can be achieved using the MCU's library functions or by manipulating the registers directly.
3. Print the debugging information
In the appropriate place in the code, insert the informational print statement that needs to be debugged. You can use the printf function or a similar library function to print the value of a variable, debug information, and so on.
4. Set up serial port reception
On a PC, you need to use serial terminal tools (such as Tera Term, Putty, etc.) to communicate with the STM32 and set the corresponding serial port receiving parameters. In general, you need to set the correct baud rate and string slogans.
5. Monitor debugging information
With the serial terminal tool, we can monitor the debug information sent by the STM32 in real time. This information helps us analyze and solve problems.
6. End of commissioning
After debugging, you can close the serial port and remove the code that prints the debugging information from the application. This reduces the size of the code and improves the efficiency of the application.
Fourth, debugging skills and precautions
In addition to using the GDB debugger and serial printout, there are some debugging tips and precautions that can help us better debug STM32 applications:
1. Affirmation of use
Where appropriate in the code, use assertions to validate the assumptions of the code. When the assertion condition is false, the program will interrupt execution and give an error message to help us locate the problem.
2. Analyze logs
During debugging, you can use logging to record the execution of a program and the values of key variables. These logs can be analyzed after debugging to help us reveal problems.
3. Step-by-step commissioning
When debugging complex problems, you can use a step-by-step debugging approach to narrow down the scope of the problem. Start at the beginning of the program, execute the code step by step, and watch the variables change to figure out what the problem is.
4. Reproduce the issue
Try to document and reproduce the problem scenario as much as possible. This helps us locate and resolve issues more accurately and avoid similar problems from happening again.
5. Update the firmware and drivers
If you encounter an issue that cannot be resolved, consider updating the STM32 firmware and drivers to fix known issues and defects.
6. Reference Documentation and Community
During debugging, you can refer to the official STM32 documentation and developer community for more debugging tips and solutions.
At last
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