How to Use Adafruit Negative RGB 2x16 LCD: Examples, Pinouts, and Specs

The Adafruit Negative RGB 2x16 LCD is a versatile display module capable of showing text and graphics in a 2-row by 16-character format. Its negative RGB backlight allows for a wide range of color customization, making it suitable for various applications such as user interfaces, status displays, and simple animations in hobbyist projects or professional devices.

• DIY electronics projects
• User interfaces for devices
• Status and information displays
• Prototyping for commercial products
• Educational tools for learning electronics and programming

• Display Type: Negative mode LCD
• Backlight Type: RGB LED
• Character Format: 2 rows by 16 characters
• Character Size: 5x8 pixel matrix per character
• Module Dimensions: 80mm x 36mm x 20mm
• Operating Voltage: 4.5V to 5.5V
• Logic Voltage: 3.3V or 5V compatible
• Current (with backlight): 20mA typical, up to 120mA max

1. Power Connections: Connect pin 2 (VCC) to a 5V power supply and pin 1 (GND) to ground.
2. Backlight: Connect pin 15 (LED+) to 5V through a current-limiting resistor and pin 16 (LED-) to ground.
3. Data Interface: Connect pins 7-14 (D0-D7) to the microcontroller's digital pins if using 8-bit mode. For 4-bit mode, only D4-D7 are used.
4. Control Pins: Connect RS, R/W, and E to digital pins on the microcontroller.
5. Contrast Adjustment: Connect VO to a potentiometer for contrast control.

• Always use a current-limiting resistor for the backlight to prevent damage.
• Adjust the contrast potentiometer to ensure characters are clearly visible.
• When using with a 3.3V logic microcontroller, ensure that the logic voltage levels are compatible.
• Avoid exposing the display to direct sunlight or high temperatures to prevent damage.

#include <LiquidCrystal.h>

// Initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
  // Set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("Hello, World!");
}

void loop() {
  // Set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // Print the number of seconds since reset:
  lcd.print(millis() / 1000);
}

• Characters not visible or very dim: Adjust the contrast potentiometer. Check the backlight current-limiting resistor and connections.
• Garbled or incorrect characters: Ensure data lines are connected properly and there are no loose connections.
• No backlight: Verify the connection and resistor for the backlight. Ensure the power supply is within the specified range.

• Double-check wiring against the pin configuration table.
• Make sure the power supply is stable and within the recommended voltage range.
• If using with a 3.3V logic device, use a logic level converter if necessary.

Q: Can I use this LCD with a 3.3V system? A: Yes, but ensure that the logic levels are compatible. You may need a logic level converter.

Q: How do I change the backlight color? A: The backlight color can be changed by using PWM signals on the RGB backlight pins. This is not covered in this basic documentation, but Adafruit provides guides on their website.

Q: What is the maximum current draw for the backlight? A: The maximum current draw for the backlight is 120mA. Always use a current-limiting resistor to prevent damage.

Q: Can I display graphics on this LCD? A: Yes, the LCD can display custom characters and simple graphics by defining custom character patterns.