Keil5 Quick Bootloader Development Practical Tips

# 1. Introduction to Keil5 IDE and Quick Start

Keil5 IDE is an integrated development environment developed by ARM for the development of embedded systems software. With its intuitive interface, powerful debugging features, and rich library support, it is deeply favored by embedded developers.

In the quick start, we will introduce the basic operations of Keil5 IDE installation, project creation, code writing, and compilation. Through these operations, developers can quickly get started with Keil5 IDE, laying the foundation for subsequent bootloader development.

# 2. Basic Development of Bootloader

### 2.1 Overview of Bootloader

#### 2.1.1 Functions and Classification of Bootloader

A bootloader is a special program that runs before the operating system is loaded, responsible for initializing hardware, loading the operating system kernel, and passing it to execution. Its main functions include:

- **Hardware Initialization:** Initialize processors, memory, peripherals, and other hardware to ensure the environment required for operating system operation.
- **Operating System Loading:** Load the operating system kernel image from external storage (such as flash, SD card).
- **Operating System Execution:** Transfer control to the operating system kernel to start the operating system.

Bootloaders can be classified based on their functions and implementation methods:

- **Single-Stage Bootloader:** Exits after loading the operating system and does not remain in memory.
- **Multi-Stage Bootloader:** Remains in memory after loading the operating system, providing additional features such as debugging, parameter passing, etc.
- **Serial Bootloader:** Loads the operating system through a serial port, eliminating the need for external memory.
- **Parallel Bootloader:** Loads the operating system through a parallel bus, faster speed.

#### 2.1.2 Bootloader Development Process

The bootloader development process generally includes the following steps:

1. **Requirement Analysis:** Determine the functions and performance requirements of the bootloader.
2. **Hardware Platform Selection:** Choose a hardware platform that supports bootloader development.
3. **Development Environment Setup:** Install necessary development tools and software.
4. **Code Writing:** Write bootloader code to implement hardware initialization, operating system loading, and execution functions.
5. **Compilation and Debugging:** Compile the bootloader code and use a debugger to debug and verify.
6. **Testing and Verification:** Test the bootloader on the target hardware to verify its functions and performance.
7. **Deployment and Maintenance:** Deploy the bootloader to the target hardware and perform maintenance and updates as needed.

### 2.2 Bootloader Development Configuration in Keil5 Environment

#### 2.2.1 Creation and Configuration of Keil5 Project

When creating a bootloader project in Keil5, the following configurations are required:

- **New Project:** Select "File" -> "New" -> "uVision Project" to create a new project.
- **Target Device Selection:** Select the target MCU in the "Device" tab.
- **Toolchain Selection:** In the "Tool Chain" tab, select an appropriate toolchain, such as ARM Compiler.
- **Bootloader Options:** In "Options for Target" -> "Device" tab, select the "Use Flash Loader" option to enable the bootloader function.

#### 2.2.2 Writing and Compiling Bootloader Code

The writing of bootloader code needs to follow the following steps:

- **Define Reset Vector:** Define the reset vector at the beginning of the code, pointing to the bootloader's entry function.
- **Hardware Initialization:** Initialize processors, memory, peripherals, and other hardware.
- **Operating System Loading:** Load the operating system kernel image from external memory.
- **Operating System Execution:** Transfer control to the operating system kernel.

When compiling the boot