Startup sequence and reset vector in Embedded C - Mini Project: Build & Apply

Startup Sequence and Reset Vector in Embedded C

📖 Scenario: You are working on a simple embedded system that needs to start correctly when powered on or reset. The system uses a reset vector to jump to the startup code, which initializes the system before running the main program.

🎯 Goal: Build a basic embedded C program that defines a reset vector and a startup sequence function. The startup sequence will initialize a variable and then call the main function. This simulates how embedded systems begin running after a reset.

📋 What You'll Learn

Define a reset vector function named Reset_Handler

Create a startup function named Startup_Code that initializes a variable system_ready to 1

Call the main function from the startup code

Define a main function that returns 0

Print the value of system_ready in main to confirm initialization

💡 Why This Matters

🌍 Real World

Embedded systems like microcontrollers use reset vectors and startup sequences to prepare hardware and software before running the main application.

💼 Career

Understanding startup sequences and reset vectors is essential for embedded software engineers working on firmware for devices like IoT gadgets, automotive controllers, and consumer electronics.

1

Create the system_ready variable

Create a global integer variable called system_ready and set it to 0.

Embedded C

# Create a global integer variable called system_ready and set it to 0
# Your code here

Need a hint?

Use int system_ready = 0; to create the variable.

2

Define the Startup_Code function

Define a function called Startup_Code that sets system_ready to 1 and then calls the main function.

Embedded C

int system_ready = 0;

// Define Startup_Code function to initialize system_ready and call main
# Your code here

Need a hint?

Write void Startup_Code() { system_ready = 1; main(); }.

3

Create the Reset_Handler function

Create a function called Reset_Handler that calls the Startup_Code function.

Embedded C

int system_ready = 0;

void Startup_Code() {
    system_ready = 1;
    main();
}

// Define Reset_Handler function to call Startup_Code
# Your code here

Need a hint?

Write void Reset_Handler() { Startup_Code(); }.

4

Define the main function and print system_ready

Define the main function that prints the value of system_ready and returns 0.

Embedded C

int system_ready = 0;

void Startup_Code() {
    system_ready = 1;
    main();
}

void Reset_Handler() {
    Startup_Code();
}

// Define main function to print system_ready and return 0
# Your code here

Need a hint?

Use printf("system_ready = %d\n", system_ready); inside main.