杰x分享(92):51单片机基础(十四)

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今天小编为您带来“51单片机基础”

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Dear, this is the LearingYard Academy!

Today, I will bring you "51 microcontroller basics"

Welcome to visit!

思维导图

Mind mapping

51单片机C51程序调试方法详解

Detailed Explanation of Debugging Methods for 51 Microcontroller C51 Programs

一、基础调试手段

I. Basic Debugging Means

LED指示灯法

LED Indicator Method

在关键代码位置插入LED亮灭控制语句，通过观察LED状态判断程序执行流程。

Insert LED on/off control statements at key code locations; judge program execution flow by observing the LED state.

例如使用P1_0=1点亮LED标记执行位置，这种方法简单直观，适合快速定位程序执行到哪个阶段。

For example, use P1_0=1 to light the LED to mark the execution position; this method is simple and intuitive, suitable for quickly locating which stage the program has reached.

数码管显示法

Seven-Segment Display Method

将关键变量值显示在数码管上，适用于观察数值变化过程。

Display the values of key variables on the seven-segment display, suitable for observing the numerical change process.

需要先编写数码管显示函数，然后在需要监控的位置调用Display(变量值)。

First write the seven-segment display function, then call Display(variable) at the location to be monitored.

这种方法能实时显示数据变化，特别适合调试涉及数值计算的程序段。

This method can display data changes in real time and is especially suitable for debugging program segments involving numerical calculations.

延时观察法

Delay Observation Method

在可疑代码段前后加入延时，通过现象变化判断程序执行时间。

Insert delays before and after suspicious code segments; judge program execution time by observing changes in phenomena.

比如在某个函数调用前后各加一个500ms延时，观察现象变化的时间点，可以判断该函数的执行耗时。

For example, add a 500 ms delay before and after a certain function call; observing the time point of the phenomenon change can determine the execution time of that function.

二、Keil开发环境调试

II. Debugging in Keil Development Environment

软件仿真步骤

Software Simulation Steps

编译成功后点击Debug按钮进入调试模式，使用F10单步执行程序。

After successful compilation, click the Debug button to enter debug mode, then press F10 to single-step the program.

在Watch窗口添加要观察的变量，通过Memory窗口查看内存数据。

Add variables to be observed in the Watch window; view memory data through the Memory window.

这是最常用的调试方式，可以精确控制程序执行流程。

This is the most commonly used debugging method, allowing precise control over program execution flow.

断点使用技巧

Breakpoint Usage Tips

在可疑代码行左侧灰色区域点击设置断点，右键断点可设置条件触发。

Click the gray area on the left of the suspicious code line to set a breakpoint; right-click the breakpoint to set conditional triggering.

断点触发后要重点查看各寄存器状态，特别是ACC、PSW等关键寄存器。

After the breakpoint is triggered, focus on checking the status of each register, especially key registers like ACC and PSW.

条件断点对于循环调试特别有用。

Conditional breakpoints are particularly useful for loop debugging.

外设寄存器观察

Peripheral Register Observation

打开Peripherals菜单，选择对应外设查看寄存器状态。

Open the Peripherals menu and select the corresponding peripheral to view its register status.

特别要关注控制寄存器和状态寄存器，比如定时器的TMOD、TCON，串口的SCON等。

Pay special attention to control and status registers, such as TMOD and TCON for timers, and SCON for the serial port.

这些寄存器的值能反映外设的工作状态。

The values of these registers can reflect the working state of the peripherals.

三、串口调试方法

III. Serial Port Debugging Methods

串口初始化设置

Serial Port Initialization Settings

必须设置正确的波特率（需与PC端一致），通常使用模式1（8位UART）。

The correct baud rate must be set (must match the PC side), typically using Mode 1 (8-bit UART).

示例代码包括配置SCON、TMOD，设置TH1/TL1波特率参数，最后启动定时器和中断。

Example code includes configuring SCON and TMOD, setting TH1/TL1 baud-rate parameters, and finally starting the timer and interrupts.

这是串口调试的基础。

This is the basis for serial port debugging.

调试信息输出

Debug Information Output

重定向printf函数到串口后，可以在关键位置输出变量值。

After redirecting the printf function to the serial port, variable values can be output at key locations.

例如printf("a=%d",a)可以实时监控变量a的变化。

For example, printf("a=%d", a) can monitor the change of variable a in real time.

输出信息要包含足够上下文，比如"函数A开始执行，参数x=%d"。

Output information should include sufficient context, such as "Function A starts execution, parameter x=%d".

数据接收处理

Data Reception and Processing

通过串口接收PC指令实现交互调试。

Interactive debugging is achieved by receiving PC commands via the serial port.

可以设计简单协议，比如收到"1"执行测试用例1，收到"2"读取某个寄存器等。

A simple protocol can be designed, such as executing test case 1 upon receiving "1", or reading a certain register upon receiving "2".

这种方法适合现场调试时灵活控制程序行为。

This method is suitable for flexibly controlling program behavior during on-site debugging.

四、常见问题排查

IV. Troubleshooting Common Problems

程序跑飞排查

Program Runaway Troubleshooting

首先检查堆栈设置是否足够，51单片机默认堆栈较小。

First check whether the stack setting is sufficient; the 51 microcontroller has a small default stack.

确认所有中断服务函数都以reti结尾。

Ensure all interrupt service functions end with reti.

如果使用看门狗，检查是否及时喂狗。

If the watchdog is used, check whether it is fed in time.

这些是程序跑飞的常见原因。

These are common causes of program runaway.

外设异常排查

Peripheral Anomaly Troubleshooting

从时钟源开始检查，确认外设时钟使能。

Start by checking the clock source and confirm the peripheral clock is enabled.

然后检查外设使能位是否设置，最后验证控制寄存器的配置值。

Then check whether the peripheral enable bit is set, and finally verify the configuration values of the control registers.

比如串口不工作，要依次检查波特率、工作模式、中断使能等设置。

For example, if the serial port does not work, check baud rate, operating mode, interrupt enable, and other settings in sequence.

内存问题排查

Memory Problem Troubleshooting

使用Keil的Memory窗口观察data/idata内存使用情况。

Use Keil's Memory window to observe data/idata memory usage.

特别注意指针操作是否越界，数组访问是否超出范围。

Pay special attention to whether pointer operations are out of bounds or whether array accesses exceed the range.

内存问题往往表现为数据莫名其妙被修改。

Memory problems often manifest as data being inexplicably modified.

五、高效调试建议

V. Efficient Debugging Suggestions

模块化调试

Modular Debugging

先单独调试底层驱动（GPIO、定时器等基础外设），再调试功能模块，最后整合测试。

First debug the underlying drivers (basic peripherals such as GPIO and timers) separately, then debug the functional modules, and finally perform integration testing.

每个模块都要设计测试用例，比如GPIO测试要验证所有管脚都能正常控制。

Each module must have test cases designed, such as GPIO testing to verify that all pins can be controlled correctly.

版本控制

Version Control

每次修改前备份代码，使用注释记录修改内容和目的。

Back up the code before each modification and use comments to record the modification content and purpose.

复杂问题要分步骤解决，每个步骤都要验证。

Complex problems should be solved step by step, and each step must be verified.

建议使用SVN或Git管理代码版本。

It is recommended to use SVN or Git to manage code versions.

记录调试日志

Recording Debug Logs

详细记录每次测试的现象、测试条件和结果。

Record in detail the phenomena, test conditions, and results of each test.

标注问题出现的特定条件，比如"只有在连续发送20个字节后才会出错"。

Mark the specific conditions under which the problem occurs, such as "only errors occur after 20 bytes are sent continuously".

最后要总结有效的解决方案。

Finally, summarize effective solutions.

六、特殊调试技巧

VI. Special Debugging Tips

利用定时器

Using Timers

用定时器测量代码执行时间，在代码段开始和结束分别读取定时器值，差值就是执行时间。

Use the timer to measure code execution time; read the timer value at the beginning and end of the code segment, and the difference is the execution time.

这种方法可以找出程序中的性能瓶颈。

This method can identify performance bottlenecks in the program.

IO口监测法

IO Port Monitoring Method

用空闲IO口输出状态信号，比如在任务开始时拉高，结束时拉低。

Use an idle IO port to output a status signal, such as pulling it high at the start of a task and low at the end.

用示波器观察这个IO的波形，可以分析程序时序和任务执行时间。

Observe the waveform of this IO with an oscilloscope to analyze program timing and task execution time.

内存填充法

Memory Fill Method

初始化时将内存填充特定值（如0xAA），运行一段时间后检查这些内存区域。

During initialization, fill memory with a specific value (e.g., 0xAA), and after running for a while, check these memory areas.

如果发现数值改变，说明有异常内存访问。

If the value changes, it indicates abnormal memory access.

这种方法对发现内存溢出特别有效。

This method is particularly effective for detecting memory overflow.

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