Writing to a hardware register in Embedded C - Mini Project: Build & Apply

Writing to a hardware register

📖 Scenario: You are programming a small embedded device. To control a hardware feature, you need to write a value to a specific memory address called a hardware register.This is common in embedded systems where you control LEDs, motors, or sensors by writing to special memory locations.

🎯 Goal: You will write a simple C program that writes a value to a hardware register using a pointer.This teaches how to access hardware registers by writing to specific memory addresses.

📋 What You'll Learn

Create a pointer variable to the hardware register address

Create a variable with the value to write

Write the value to the hardware register using the pointer

Print the value written to verify

💡 Why This Matters

🌍 Real World

Embedded developers often write to hardware registers to control device features like LEDs, timers, or communication modules.

💼 Career

Understanding how to write to hardware registers is essential for embedded systems engineers and firmware developers working with microcontrollers.

1

Create a pointer to the hardware register

Create a pointer variable called reg_ptr that points to the hardware register address 0x40021000. Use volatile unsigned int * as the pointer type.

Embedded C

// Your code here

Need a hint?

Use a pointer cast to volatile unsigned int * and assign the address 0x40021000.

2

Create a value to write

Create an unsigned int variable called value and set it to 0xABCD1234.

Embedded C

volatile unsigned int *reg_ptr = (volatile unsigned int *)0x40021000;
// Your code here

Need a hint?

Declare value as unsigned int and assign 0xABCD1234.

3

Write the value to the hardware register

Write the value to the hardware register by assigning *reg_ptr = value;.

Embedded C

volatile unsigned int *reg_ptr = (volatile unsigned int *)0x40021000;
unsigned int value = 0xABCD1234;
// Your code here

Need a hint?

Use the pointer reg_ptr to write the value by dereferencing it.

4

Print the value written

Use printf to print the value written to the hardware register in hexadecimal format with the message: "Value written: 0x%X\n".

Embedded C

volatile unsigned int *reg_ptr = (volatile unsigned int *)0x40021000;
unsigned int value = 0xABCD1234;
*reg_ptr = value;
// Your code here

Need a hint?

Use printf("Value written: 0x%X\n", value); inside main() to display the value.