How to use C++ to build efficient and reliable embedded system touch screen applications

How to use C to build efficient and reliable embedded system touch screen applications

Driven by modern technology, touch screen technology has become an indispensable part of smart devices . To build efficient and reliable embedded system touch screen applications, you need to choose the appropriate programming language and development environment. This article will focus on how to build such an application using the C programming language, with corresponding code examples.

1. Preparation
To start building touch screen applications for embedded systems, you first need a compiler and development environment that supports C. This article uses Arduino as an example to demonstrate code examples. Arduino is an open source electronic prototyping platform that is easy to use and widely used in embedded system development.

First, make sure you have installed the Arduino development environment and connected an Arduino development board that is compatible with the touch screen module.

2. Write basic code
Let’s start by writing some basic code. One of the core functions of touch screen applications is to respond to touch events and perform corresponding operations based on the touch location.

#include <TouchScreen.h>

// 定义触摸屏引脚连接
#define TS_PIN_XP A2
#define TS_PIN_YM 9
#define TS_PIN_XM A1
#define TS_PIN_YP 8

// 定义触摸屏尺寸
#define TS_MINX 100
#define TS_MAXX 920
#define TS_MINY 70
#define TS_MAXY 900

TouchScreen ts = TouchScreen(TS_PIN_XP, TS_PIN_YP, TS_PIN_XM, TS_PIN_YM);

void setup() {
  Serial.begin(9600);
}

void loop() {
  // 读取触摸位置
  TSPoint p = ts.getPoint();

  // 通过校验触摸点来排除无效的触摸事件
  if (p.z > 200 && p.z < 1000) {
    int x = map(p.x, TS_MINX, TS_MAXX, 0, 800); // 将x值映射到屏幕宽度
    int y = map(p.y, TS_MINY, TS_MAXY, 0, 480); // 将y值映射到屏幕高度

    Serial.print("X: ");
    Serial.print(x);
    Serial.print(" Y: ");
    Serial.println(y);
  }

  // 处理其他的业务逻辑
}

In the above code, we first define the connection of the touch screen pins and set the size range of the touch screen by using the TouchScreen library. In the loop() function, we get the touch coordinates by calling the getPoint() function, and map them to the screen by calling the map() function In actual size. In this way, we can obtain the specific touch position and output it to the serial monitor.

3. Implement more advanced functions
In addition to basic touch position detection, we can also implement more advanced functions, such as menu switching, button response, etc.

To achieve these functions, we can use object-oriented programming ideas to organize the code. Below is a sample code that implements a simple button class.

class Button {
  private:
    int x;
    int y;
    int width;
    int height;
    bool pressed;

  public:
    Button(int _x, int _y, int _width, int _height) {
      x = _x;
      y = _y;
      width = _width;
      height = _height;
      pressed = false;
    }

    void update() {
      // 检测触摸位置是否在按钮范围内
      if (ts.touched()) {
        TSPoint p = ts.getPoint();
        if (p.x > x && p.x < (x + width) && p.y > y && p.y < (y + height)) {
          pressed = true;
        } else {
          pressed = false;
        }
      } else {
        pressed = false;
      }
    }

    bool isPressed() {
      return pressed;
    }
};

Button myButton(100, 200, 80, 40);

void setup() {
  Serial.begin(9600);
}

void loop() {
  myButton.update();

  if (myButton.isPressed()) {
    Serial.println("Button is pressed");
  }

  // 处理其他的业务逻辑
}

In the above code, we define a button class Button and instantiate a button object by passing in coordinates and dimensions. In the update() function, we detect whether the touch position is within the button range by calling the ts.touched() and ts.getPoint() functions. and update the button's state. In the loop() function, we check whether the button is pressed by calling the isPressed() function of the button object, and output the corresponding information on the serial monitor.

4. Summary
By using the C programming language, we can build efficient and reliable touch screen applications in embedded systems. This article introduces basic touch position detection and button response code examples, hoping to bring some inspiration to readers. Of course, in actual development, there are many other functions and technologies that need to be involved, and readers can further study and explore.

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