Example Code for Arduino-Basic Test

Last revision 2026/01/18

This guide covers how to set up an Arduino with a TFT LCD touchscreen using the DFRobot_GDL library, offering sample code to demonstrate various graphic painting effects. It includes detailed instructions for hardware and software preparation, wiring diagrams, and explanations of the functions used in the code.

Hardware Preparation

  • DFRduino UNO R3 (or similar) x 1
  • 3.5”480x320 TFT LCD with Capacitive Touchscreen x1
  • Wires

Software Preparation

Wiring Diagram

Connection Diagram

Other Preparation Work

  1. All the demos of this product are all stored in the DFRobot_GDL->example->basic file
  2. Before burning the demo, please open the corresponding materialized function (DFRobot_ST7789_240x320_HW_SPI)

Sample Code

/*!
 * @file basicTest.ino
 * @brief Demonstrate various graphic painting effects
 * @n This demo supports Arduino Uno, Leonardo, Mega2560, FireBeetle-ESP32, FireBeetle-ESP8266, and FireBeetle-M0.
 * @copyright Copyright (c) 2010 DFRobot Co. Ltd (http://www.dfrobot.com)
 * @licence The MIT License (MIT)
 * @author [LuoYufeng] ([email protected])
 * @version V0.1
 * @date 2020-01-07
 * @url https://github.com/DFRobot/DFRobot_GDL
 */
#include "DFRobot_GDL.h"
/*M0*/
#if defined ARDUINO_SAM_ZERO
#define TFT_DC  7
#define TFT_CS  5
#define TFT_RST 6
/*ESP32 and ESP8266*/
#elif defined(ESP32) || defined(ESP8266)
#define TFT_DC  D2
#define TFT_CS  D6
#define TFT_RST D3
/*AVR series mainboard*/
#else
#define TFT_DC  2
#define TFT_CS  3
#define TFT_RST 4
#endif

/**
 * @brief Constructor Constructor of hardware SPI communication
 * @param dc Command/data line pin for SPI communication
 * @param cs Chip select pin for SPI communication
 * @param rst reset pin of the screen
 */
//DFRobot_ST7789_240x240_HW_SPI screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);
//DFRobot_ST7789_240x320_HW_SPI screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);
//DFRobot_ILI9341_240x320_HW_SPI  screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);
//DFRobot_ILI9488_320x480_HW_SPI screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);
/* M0 mainboard DMA transfer */
//DFRobot_ST7789_240x240_DMA_SPI screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);
//DFRobot_ST7789_240x320_DMA_SPI screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);
//DFRobot_ILI9341_240x320_DMA_SPI screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);
//DFRobot_ILI9488_320x480_DMA_SPI screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);


/*
 *User-selectable macro definition color
 *COLOR_RGB565_BLACK   COLOR_RGB565_NAVY    COLOR_RGB565_DGREEN   COLOR_RGB565_DCYAN 
 *COLOR_RGB565_MAROON  COLOR_RGB565_PURPLE  COLOR_RGB565_OLIVE    COLOR_RGB565_LGRAY     
 *COLOR_RGB565_DGRAY   COLOR_RGB565_BLUE    COLOR_RGB565_GREEN    COLOR_RGB565_CYAN  
 *COLOR_RGB565_RED     COLOR_RGB565_MAGENTA COLOR_RGB565_YELLOW   COLOR_RGB565_ORANGE           
 *COLOR_RGB565_WHITE   
 */
 
void setup() {
  Serial.begin(115200);
  screen.begin();
}

void loop(){
    testDrawPixel();
    testLine();
    testFastLines(COLOR_RGB565_PURPLE,COLOR_RGB565_YELLOW);       
    testRects(COLOR_RGB565_BLACK,COLOR_RGB565_WHITE);
    testRoundRects();
    testCircles(24,COLOR_RGB565_BLUE);
    testTriangles(COLOR_RGB565_YELLOW);
    testPrint();

}

/* Test to draw a pixel*/
void testDrawPixel() {
  //Clear screen
  screen.fillScreen(COLOR_RGB565_BLACK);
  int x = 0;
  int y = screen.height();
  for(int i = 0; i <= screen.width()/2; i += 10){
    for (x = screen.width() - i; x >= i; x-=10 ){
      /*
       * @ brief draw a pixel
       * @ param x coordinate
       *         y coordinate
       * c pixel color
       */
      screen.drawPixel(x, y, COLOR_RGB565_ORANGE);
      delay(10);
    }
	
    for (y = screen.height() - i; y >= i; y-=10){
      screen.drawPixel(x, y, COLOR_RGB565_ORANGE);
      delay(10);
    }
	
    for (x = i; x <= screen.width() - i + 1; x+=10 ){
      screen.drawPixel(x, y, COLOR_RGB565_ORANGE);
      delay(10);
    }
	
    for (y = i; y <= screen.height() - i + 1; y+=10){
      screen.drawPixel(x, y, COLOR_RGB565_ORANGE);
      delay(10);
    }
  }
}

/* Test to draw a line*/
void testLine(){
// 0x00FF is the color data in the format of RGB565
  uint16_t color = 0x00FF;
  screen.fillScreen(COLOR_RGB565_BLACK);
  for (int16_t x=0; x < screen.width(); x+=6) {
    /*
     * @ brief draw a line
     * @ param x0 The x-coordinate of the first vertex
     *         y0 The y-coordinate of the first vertex
     *         x1 The x-coordinate of the second vertex
     *         y1 The y-coordinate of the second vertex
     *         c line color
     */
    screen.drawLine(/*x0=*/screen.width()/*Screen width*//2, /*y0=*/screen.height()/*Screen height*//2, /*x1=*/x, /*y1=*/0, /*c=*/color+=0x0700);
  }
  for (int16_t y=0; y < screen.height(); y+=6) {
    screen.drawLine(screen.width()/2, screen.height()/2, screen.width(), y, color+=0x0700);
  }
 
  for (int16_t x = screen.width(); x >= 0; x-=6) {
    screen.drawLine(screen.width()/2, screen.height()/2, x,screen.height(), color+=0x0700);
  }
  
  for (int16_t y = screen.height(); y >= 0; y-=6) {
    screen.drawLine(screen.width()/2, screen.height()/2, 0, y, color+=0x0700);
  }
}

/* Test to fast draw line(need to set delay), only horizontal line and vertical line */
void testFastLines(uint16_t color1, uint16_t color2) {
  for (int16_t y=0; y < screen.height(); y+=4) {
    /*
     * @ brief draw a line
     * @ param x The x-coordinate of the first vertex
     *         y The y-coordinate of the first vertex
     *         w Length of line segment
     *         c line color
     */
    screen.drawFastHLine(/*x=*/0, /*y=*/y, /*w=*/screen.width(),/*c=*/color2);
    delay(10);
  }
  
  for(int16_t x=0; x < screen.width(); x+=3) {
    /*
     * @ brief draw a line
     * @ param x The x-coordinate of the first vertex
     *         y The y-coordinate of the first vertex
     *         h length of line segment
     *         c line color
     */
    screen.drawFastVLine(/*x=*/x, /*y=*/0, /*h=*/screen.height(), /*c=*/color1);
    delay(10);
  }
}

/* Test to draw a rectangle*/
void testRects(uint16_t color1, uint16_t color2) { 
    screen.fillScreen(COLOR_RGB565_BLACK);
    int16_t x=screen.width()-12;
    for (; x > 100; x-=screen.width()/40) {
      /*
       * @ brief draw a hollow rectangle
       * @ param x The x-coordinate of the vertex 
       * @ param y The y-coordinate of the vertex
       * @ param w horizontal side length
       * @ param h longitudinal side length
       * @ param color Fill color, RGB color with 565 structure
       */
      screen.drawRect(/*x=*/screen.width()/2 -x/2, /*y=*/screen.height()/2 -x/2 , /*w=*/x, /*h=*/x, /*color=*/color2+=0x0F00);
      delay(100);
    }
	
    /*
     * @ brief draw a filled rectangle
     * @ param x The x-coordinate of the vertex
     * @ param y The y-coordinate of the vertex
     * @ param w horizontal side length
     * @ param h longitudinal side length
     * @ param color Fill color, RGB color with 565 structure
     */
    screen.fillRect(/*x=*/screen.width()/2 -x/2, /*y=*/screen.height()/2 -x/2 , /*w=*/x, /*h=*/x, /*color=*/color2);
    delay(100);
    for(; x > 6; x-=screen.width()/40){
      screen.drawRect(screen.width()/2 -x/2, screen.height()/2 -x/2 , x, x, color1);
      delay(100);
    }
}

/* Test to draw a rounded rectangle */
void testRoundRects() {
  screen.fillScreen(COLOR_RGB565_BLACK);
// 0xF00F is the color data in the format of RGB565
  int color = 0xF00F;
  int i;
  int x = 0;
  int y = 0;
  int w = screen.width()-3;
  int h = screen.height()-3;
  for(i = 0 ; i <= 16; i+=2) {
    /*
     * @ brief Draw a hollow rounded rectangle
     * @ param x0 The x-coordinate of the start vertex 
     * @ param y0 The y-coordinate of the start vertex 
     * @ param w horizontal side length
     * @ param h longitudinal side length
     * @ param radius Round corner radius
     * @ param color border color, 565 structure RGB color
     */
    screen.drawRoundRect(/*x0=*/x, /*y0=*/y, /*w=*/w, /*h=*/h, /*radius=*/20, /*color=*/color);
    x+=5;
    y+=5;
    w-=10;
    h-=10;
    color+=0x0100;
    delay(50);
  }
  for(i = 0 ; i <= 16; i+=2) {
    /*
     * @ brief Draw a filled and rounded rectangle
     * @ param x0 The x-coordinate of the start vertex
     * @ param y0 The y-coordinate of the start vertex
     * @ param w horizontal side length
     * @ param h longitudinal side length
     * @ param radius Round corner radius
     * @ param color Fill color, RGB color with 565 structure
     */
    screen.fillRoundRect(/*x0=*/x, /*y0=*/y, /*w=*/w, /*h=*/h, /*radius=*/10, /*color=*/color);
    x+=5;
    y+=5;
    w-=10;
    h-=10;
    color+=0x0500;
    delay(50);
  }
}

/* Test to draw a circle */
void testCircles(uint8_t radius, uint16_t color) {
  screen.fillScreen(COLOR_RGB565_BLACK);
  for (int16_t x=radius; x <=screen.width()-radius; x+=radius*2) {
    for (int16_t y=radius; y <=screen.height()-radius; y+=radius*2) {
      /*
       * @ brief Draw a hollow circle
       * @ param x0 The x-coordinate of the center point
       * @ param y0 The y-coordinate of the center point
       * @ param r radius
       * @ param color Circle color, RGB color with 565 structure
       */
      screen.drawCircle(/*x0=*/x, /*y0=*/y, /*r=*/radius, /*color=*/color);
        if(x == y ||x == -y ||x == y + 2*radius)
          /*
           * @ brief Draw a filled circle
           * @ param x0 The x-coordinate of the center point
           * @ param y0 The y-coordinate of the center point
           * @ param r radius
           * @ param color Fill color, RGB color with 565 structure
           */
          screen.fillCircle(/*x0=*/x, /*y0=*/y, /*r=*/radius, /*color=*/color);
       color += 800;
       delay(100);
    }
  }
}

/* Test to draw a triangle */
void testTriangles(uint16_t color){
  screen.fillScreen(COLOR_RGB565_BLACK);
  
  for (int16_t i=0; i <=screen.width(); i+=24)
    /*
     * @ brief Draw a hollow triangle
     * @ param x0 The x-coordinate of the start vertex
     * @ param y0 The y-coordinate of the start vertex
     * @ param x1 The x-coordinate of the second vertex
     * @ param y1 The y-coordinate of the second vertex
     * @ param x2 The x-coordinate of the third vertex
     * @ param y2 The y-coordinate of the third vertex
     * @ param color border color, 565 structure RGB color
     */
    screen.drawTriangle(/*x0=*/i,/*y0=*/0,/*x1=*/0,/*y1=*/screen.height()-i,/*x2=*/screen.width()-i,/*y2=*/screen.height(), /*color=*/color);
	
  for (int16_t i=0; i <screen.width(); i+=24)
    screen.drawTriangle(screen.width(),i*4/3,0,screen.height()-i*4/3,i,0, color);

  for (int16_t i=0; i <screen.width(); i+=24)
    screen.drawTriangle(screen.width(),i*4/3,i,0,screen.width()-i,screen.height(), color);

  color = COLOR_RGB565_RED;
  for (int16_t i=0; i <=screen.width(); i+=24)
     /*
      * @ brief Draw a filled triangle
      * @ param x0 The x-coordinate of the start vertex
      * @ param y0 The y-coordinate of the start vertex
      * @ param x1 The x-coordinate of the second vertex
      * @ param y1 The y-coordinate of the second vertex
      * @ param x2 The x-coordinate of the third vertex
      * @ param y2 The y-coordinate of the third vertex
      * @ param color Fill color, RGB color with 565 structure
      */
    screen.fillTriangle(/*x0=*/i,/*y0=*/0,/*x1=*/0,/*y1=*/screen.height()-i,/*x2=*/screen.width()-i,/*y2=*/screen.height(), /*color=*/color+=100);
	
  for (int16_t i=0; i <screen.width(); i+=24)
    screen.fillTriangle(screen.width(),i*4/3,0,screen.height()-i*4/3,i,0, color+=100);

  for (int16_t i=0; i <screen.width(); i+=24)
    screen.fillTriangle(screen.width(),i*4/3,i,0,screen.width()-i,screen.height(), color+=100);
}

void testPrint() {
  // 0x00FF is the color data in the format of RGB565
  int16_t color = 0x00FF;
   // Set text wrapping mode
   // true = Text word wrap, false = No word wrap
  screen.setTextWrap(false);
  //Fill color, RGB color with 565 structure
  screen.fillScreen(COLOR_RGB565_BLACK);
  
  //Set the coordinate position x = 0, y = 50
  screen.setCursor(0, 50);
  //Set the text color; this is a changeable value
  screen.setTextColor(color+=0x3000);
  //Set text size to 0
  screen.setTextSize(0);
  //Output text
  screen.println("Hello World!");
  
  screen.setTextColor(color+=0x3000);
  //Set text size to 1
  screen.setTextSize(1);
  screen.println("Hello World!");
  
  screen.setTextColor(color+=0x3000);
  //Set text size to 2
  screen.setTextSize(2);
  screen.println("Hello World!");
  
  screen.setTextColor(color+=0x3000);
  //Set text size to 3
  screen.setTextSize(3);
  screen.println("Hello World!");
  
  screen.setTextColor(color+=0x3000);
  //Set text size to 4
  screen.setTextSize(4);
  screen.println("Hello!"); 
  //Set text size to 5
  screen.setTextSize(5);
  screen.print("Hello!");
  delay(2000);
  
  //Set coordinate position x = 0, y = 0
  screen.setCursor(0, 0);
  //Fill color, RGB color with 565 structure
  screen.fillScreen(COLOR_RGB565_BLACK);
  screen.setTextSize(2);
  screen.setTextColor(color+=0x3000);
  screen.print("a = ");
  
  screen.setTextColor(color+=0x3000);
  int a = 1234;
  screen.println(a, 1);
  screen.setTextColor(color+=0x3000);
  screen.print(8675309, HEX);
  screen.println("this is HEX!");
  screen.println("");
  
  screen.setTextColor(color+=0x0F00);
  screen.println("running for: ");
  screen.setTextColor(color+=0x0F00);
  //Output time in millisecond
  screen.print(millis());
  screen.setTextColor(color+=0x0F00);
  screen.println("/1000 seconds.");
  
  char *text = "Hi DFRobot!";
  screen.setTextColor(color+=0x0F00);
  screen.setTextWrap(true);
  screen.setTextSize(3);
  screen.println(text);
  //screen.setFonts((const gdl_Font_t *)SIMKAIFont18ptBitmaps);
  screen.println(text);
  delay(2000);
}

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