C++ Embedded Development: Basics and Practices of Hardware Programming

Introduction

With the rapid development of the Internet of Things and smart devices, the demand for embedded systems is increasing. C++, as an efficient and flexible programming language, is widely used in embedded development. This article will introduce the basic concepts of C++ in embedded development, the fundamentals of hardware programming, and some simple practical examples.

Introduction to Embedded Systems

An embedded system is a computer system designed for specific functions, typically integrated into other devices. Unlike general-purpose computers, embedded systems usually have the following characteristics:

• Limited Resources: Memory, processing power, and storage space are relatively small.
• Real-time Performance: Many applications require tasks to be completed within strict time constraints.
• Specialization: Optimized for specific tasks.

Advantages of C++ in Embedded Development

1. Object-Oriented Programming: C++ supports object-oriented programming, making code easier to manage and extend.
2. Superior Performance: C++ provides the ability to operate close to the hardware while maintaining high execution efficiency.
3. Rich Library Support: There are many ready-to-use libraries available, accelerating the development process.

Basics of Hardware Programming

1. GPIO (General Purpose Input/Output)

GPIO is the most basic interface on a microcontroller, used to control external devices such as LEDs and buttons. In this section, we will demonstrate how to control GPIO pins using C++ through a simple example.

Example Code – Control LED Blinking

#include <iostream>
#include <wiringPi.h> // Using WiringPi library for GPIO operations
#include <unistd.h>  // For sleep function
#define LED_PIN 0    // Define LED connected to GPIO0 pin
int main() {
    wiringPiSetup(); // Initialize WiringPi library
    pinMode(LED_PIN, OUTPUT); // Set pin as output mode
    while (true) {
        digitalWrite(LED_PIN, HIGH); // Turn on LED
        sleep(1);                    // Wait for 1 second
        digitalWrite(LED_PIN, LOW);  // Turn off LED
        sleep(1);                    // Wait for 1 second
    }
    return 0;
}

Code Explanation:

• <span>wiringPiSetup()</span> initializes the WiringPi library so that we can access GPIO pins.
• <span>pinMode(LED_PIN, OUTPUT)</span> sets the specified pin as output mode so that we can control it.
• In an infinite loop, we use the<span>digitalWrite()</span> function to turn the LED on and off, waiting one second each time.

2. Serial Communication (UART)

Serial communication is a common data transmission method suitable for information exchange between microcontrollers and other devices. Below is a simple example of sending data via serial communication.

Example Code – Sending Data via Serial

#include <iostream>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>
int main() {
    int serialPort = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY);
    if (serialPort == -1) {
        std::cerr << "Unable to open serial port" << std::endl;
        return -1;
    }
    struct termios options;
    tcgetattr(serialPort, &options);
    options.c_cflag = B9600 | CS8 | CLOCAL | CREAD;
    options.c_iflag = IGNPAR;
    tcflush(serialPort, TCIFLUSH);
    tcsetattr(serialPort, TCSANOW, &options);
    const char *msg = "Hello from Embedded System!\n";
    write(serialPort, msg, strlen(msg));
    close(serialPort);
    return 0;
}

Code Explanation:

• <span>open("/dev/ttyS0", ...)</span> opens the specified serial port, assuming the first serial port is used here.
• Using the<span>termios</span> structure to configure serial port parameters, including baud rate, character size, and other settings.
• Finally, the<span>write()</span> function sends the string to the serial port and closes the port.

Suggested Practical Projects

To reinforce the knowledge learned, you can try the following small projects:

1. Create a temperature monitoring device that connects a temperature sensor to a microcontroller and displays the temperature value on an LCD screen.
2. Develop a small game based on button input to control the state of multiple LEDs, such as a “guess the number” game where the user presses buttons to select numbers and observes corresponding light feedback.

Conclusion

This article introduced the basic concepts and applications of C++ in embedded development, including hardware interfaces like GPIO and UART. It is hoped that this content can help beginners understand and start their own embedded projects. In practical operations, hands-on practice will deepen the understanding of theoretical knowledge.