LCD Character Modules

Overview: LCD character modules are alphanumeric displays commonly used in embedded systems for text-based output.

Common Types

• • 16x2: 16 characters per line, 2 lines
• • 20x4: 20 characters per line, 4 lines
• • 16x1 / 8x2: Smaller variants

Interface

Parallel (HD44780): 4-bit or 8-bit mode, requires 6–11 GPIOs

I²C Backpack: Reduces pins to 2 (SDA, SCL), uses PCF8574T

SPI: Less common, requires 3–4 wires

Pinout (Standard 14-pin)

Usage Tips

• • Use 4-bit mode to save MCU pins
• • Add current-limiting resistor (~220Ω) for backlight
• • Initialize with proper delay sequence (check datasheet)
• • I²C modules require pull-up resistors (typically 4.7kΩ)