This is fast Arduino library for LCD HD44780 and its clones (S6A0069, KS0066U, NT3881D, LC7985, ST7066, SPLC780, WH160xB, AIP31066, GDM200xD). It works in 4-bit mode via I²C bus with 8-bit PCF8574/PCF8574A I/O expander.

The 99.9% of all PCF8574 I²C backpacks from eBay connected like this:

The initialization string:

LiquidCrystal_I2C lcd(PCF8574_ADDR_A21_A11_A01, 4, 5, 6, 16, 11, 12, 13, 14, POSITIVE);

But what if your I²C backpack is different? The LCD pin 4/RS connected to PCF8574 port P6 & LCD pin 13/DB6 connected to PCF8574 port P0.

The initialization string:

LiquidCrystal_I2C lcd(PCF8574_ADDR_A21_A11_A01, 13, 5, 6, 16, 11, 12, 4, 14, POSITIVE);

Supports:

• Arduino AVR
• Arduino ESP8266
• Arduino ESP32
• Arduino STM32