If you have electronics project that need many LCD display with limited MCU IO pin out, you can use this method to accomplish it. Jesus Echavarria has successfully interface 8 LCD displays and 24 Leds with only two wires: SDA and SCL from an I2C bus. The project uses MCP23017 (16-Bit I/O Expander with Serial Interface) to interface a 2×16 LCD display with AT89C51RE2 microcontroller using a standard I2C bus. In simple words, MCP23017 is like LCD parallel to I2C LCD converter.
The project’s firmware is written in C and is compiled with Keil C51 compiler. With little modification in source code, you implement this method to other MCU like Arduino or PIC.