Display Test

DisplayTest.ino tests the display and the brightness control. After initialization, the screen is filled with different colors. Then, the brightness increases step by step from 0 to the maximum and back to 0 while printing the brightness value on the screen.

Note

Install the Adafruit_ST7789 Arduino Library and its dependencies through the Arduino IDE.

Tip

Check the Adafruit Documentation pages to learn what is possible with their libraries:

• Adafruit GFX Library Overview
• Adafruit GFX Library Reference You can also check the Example sketches that come with the library in Arduino IDE under File > Examples > Adafruit ST7735 and ST7789 Library.

DisplayTest.ino

#include <Adafruit_GFX.h>    // Core graphics library
#include <Adafruit_ST7789.h> // Hardware-specific library for ST7789
#include <SPI.h>

#define LCD_DC 1
#define LCD_CS 2
#define LCD_BL 3
#define LCD_RST -1

#define SPI_MOSI 11
#define SPI_SCK 12
#define SPI_MISO 13

Adafruit_ST7789 lcd = Adafruit_ST7789(LCD_CS, LCD_DC, LCD_RST);

void setup() {
  Serial.begin(115200);
  SPI.begin(SPI_SCK, SPI_MISO, SPI_MOSI, LCD_CS);

  lcd.init(240, 240);
  lcd.setRotation(1);

  pinMode(LCD_BL, OUTPUT);

  Serial.println("STARTED");
}

void loop() {
  lcd.fillScreen(ST77XX_WHITE);
  lcd.setTextColor(ST77XX_BLACK);

  analogWrite(LCD_BL, 127);

  lcd.fillScreen(ST77XX_BLACK);
  delay(1000);
  lcd.fillScreen(ST77XX_RED);
  delay(1000);
  lcd.fillScreen(ST77XX_GREEN);
  delay(1000);
  lcd.fillScreen(ST77XX_BLUE);
  delay(1000);
  lcd.fillScreen(ST77XX_WHITE);
  delay(1000);

  lcd.fillScreen(ST77XX_BLACK);
  delay(3000);

  lcd.setCursor(0,0);
  lcd.print("Brightness:");

  analogWrite(LCD_BL, 0);
  lcd.fillScreen(ST77XX_WHITE);

  for(int i=0; i<256 ; i+=2){
    analogWrite(LCD_BL, i);
    lcd.print(";" + String(i));
    delay(25);
  }

  for(int i=255; i>=0 ; i-=2){
    analogWrite(LCD_BL, i);
    lcd.print(";" + String(i));
    delay(25);
  }

  delay(3000);
}