Keil5 Linker Script Configuration: Step-by-Step Guide

# 1. Keil5 Linker Script Overview

Keil5 linker script is a text file that instructs the Keil5 compiler and linker on how to link source code files into an executable image. It defines the memory layout, peripheral addresses, and interrupt vector tables, among other crucial configurations. Through linker scripts, developers can optimize code size, performance, and functionality to meet the requirements of specific applications.

# 2. Keil5 Linker Script Configuration Fundamentals

### 2.1 Understanding the Role of Linker Scripts

Linker scripts play a vital role in embedded system development, responsible for linking compiled object files (.obj) into an executable image file (.hex, .bin). They define the layout of the code and data segments within the target files and their positions in the final image file. With careful linker script configuration, code size, performance, and memory utilization can be optimized.

### 2.2 Syntax and Structure of Linker Scripts

Keil5 linker scripts follow a specific syntax and structure composed of the following parts:

- **SECTION directives:** Define code and data segments and specify their attributes (e.g., executable, readable, writable).
- **MEMORY directives:** Define memory areas and specify their attributes (e.g., size, address range).
- **INCLUDE directives:** Include other linker script files.
- **ENTRY directives:** Specify the program's entry point.
- **Other directives:** Used to configure interrupt vector tables, stacks, and symbol tables, among others.

Here is a simple example of a linker script:

/* Keil5 Linker Script Example */

MEMORY
{
   FLASH (rx) : ORIGIN = 0x***, LENGTH = 128K
   RAM (rw)   : ORIGIN = 0x***, LENGTH = 64K
}

SECTIONS
{
   .text : {
     LOAD = FLASH,
     FILL = 0xFF
   }
   .data : {
     LOAD = RAM,
     FILL = 0x00
   }
}

ENTRY(Reset_Handler)

In this example, the linker script defines two memory areas (FLASH and RAM) and creates two code segments (.text and .data). The .text segment is loaded into FLASH, while the .data segment is loaded into RAM. The Reset_Handler function is specified as the program's entry point.

### Code Block Example:

MEMORY
{
   FLASH (rx) : ORIGIN = 0x***, LENGTH = 128K
   RAM (rw)   : ORIGIN = 0x***, LENGTH = 64K
}

**Code Logic Analysis:**

This code defines two memory areas: FLASH and RAM. The FLASH area starts at address 0x*** and has a length of 128K. The RAM area starts at address 0x*** and has a length of 64K.

**Parameter Explanation:**

- **ORIGIN:** Specifies the starting address of the memory area.
- **LENGTH:** Specifies the length of the memory area.
- **rx:** Specifies that the FLASH area is read-only (read-only).
- **rw:** Specifies that the RAM area is readable and writable (read-write).

### Table Example:

| Memory Area | Starting Address | Length | Attributes |
|-------------|------------------|--------|------------|
| FLASH | 0x*** | 128K | Read-only |
| RAM | 0x*** | 64K | Read-write|

### Flowchart Example:

graph LR
subgraph Memory Areas
     FLASH[FLASH] --> FLASH_Start[0x***]
     FLASH_Start[0x***] --> FLASH_Length[128K]
     RAM[RAM] --> RAM_Start[0x***]
     RAM_Start[0x***] --> RAM_Length[64K]
end

# 3. Keil5 Linker Script Configuration in Practice

### 3.1 Configuring Memory Mapping and Peripheral Addresses

The linker script is responsible for defining the memory layout for programs and data. In Keil5, the `MEMORY` and `REGION` directives can be used to configure memory mapping.

MEMORY
{
   FLASH (rx) : ORIGIN = 0x***, LENGTH = 128K
   RAM (rw)    : ORIGIN = 0x***, LENGTH = 32K
}

This code defines two memory areas: `FLASH` and `RAM`. The `FLASH` area starts at address `0x***`, is 128KB in size, and is used for storing program