Adafruit I2c / SPI character LCD backpack - STEMMA QT / Qwiic

Character LCD backlight backpacks offer an efficient solution for incorporating displays into microcontroller projects without extensive wiring. By utilizing simple I2C and SPI expanders, the backpack reduces pin requirements significantly, necessitating only 2 pins for I2C and 3 for SPI connections.

Featuring compatibility with any standard character LCD with a 16-pin header, the backpack supports sizes from 8x1 to 20x4. For seamless integration, a pre-soldered terminal block facilitates straightforward connections. Arduino and CircuitPython users benefit from a compatible library simplifying transition from '6 pin' wiring projects.

Enhanced functionality includes a 3-5V boost circuit, allowing operation of 5V LCDs using 3V power. The conveniently designed contrast potentiometer eases adjustments, and the addition of qwiic compatible STEMMA QT connectors eliminates the need for soldering power lines.

Special features include optional I/O expansion capabilities via MCP23008 or SPI 74HC595, empowering advanced users for broader applications. Mechanically and code-wise, the backpack serves as a direct replacement, maintaining size and shape while improving usability.