In this lesson, we will learn how to use LCD1602 to display characters and strings.
– 1 * Raspberry Pi
– 1 * Breadboard
– 1 * LCD1602
– 1 * Potentiometer
– Jumper wires
LCD1602, or character type LCD1602, is a dot matrix LCD module specially used to display letters, figures, symbols, and so on. It consists of many 16*2 dot matrixes, and each one is composed of 5*7 or 5*11 character bit. Each character bit can display one character. There is a dot space between each adjacent character bit. Also there is a dot space between each row. The dot space functions as a character space or line space; thus, LCD1602 cannot display graphics very well. It is widely used in pocket instruments and low power application systems due to its micro power consumption, small size, richness in contents, ultra-thinness and lightness.
LCD1602 uses the standard 16-pin port, among which:
Pin 1 (GND): connected to Ground
Pin 2 (Vcc): connected to 5V power supply
Pin 3 (Vo): used to adjust the contrast of LCD1602; the level is lowest when it’s connected to a positive power supply, and highest when connected to ground (you can connect a 10K potentiometer to adjust its contrast when using LCD1602)
Pin 4 (RS): register select pin that controls where in the LCD’s memory you are writing data to. You can select either the data register, which holds what goes on the screen, or an instruction register, which is where the LCD’s controller looks for instructions on what to do next.
Pin 5 (R/W): to read/write signals; it reads signals when supplied with high level (1), and writes when low level (0) (in this experiment, you only need to write data to LCD1602, so just connect this pin to ground)
Pin 6 (E): An enable pin that, when low-level energy is supplied, causes the LCD module to execute relevant instructions
Pin 7 (D0-D7): pins that read and write data
A and K: controlling LCD backlight
LCD1602 has two operation modes: 4-bit and 8-bit. When the IOs of microprocessor (MCU) are insufficient, you can choose 4-bit mode, under which only pins D4~D7 are used. After connecting the circuit, you can operate LCD1602 by Raspberry Pi.
Step1: Build the circuit (please be sure the pins are connected correctly. Otherwise, characters will not be displayed properly):
For C Language Users:
Step 2: Change directory.
Step 3: Compile.
gcc lcd1602_2.c -o lcd1602_2 -lwiringPiDev -lwiringPi
Step 4: Run.
For Python Users:
Step 2: Change directory.
Step 3: Run.
sudo python3 13_lcd1602.py
You should see two lines of characters displayed on the LCD1602: “SUNFOUNDER” and “Hello World ! 🙂“.
In this experiment, the LCD1602 is driven in the 4-bit mode. You can try programming by yourself to drive it in the 8-bit mode.