Davide Gironi has posted an I2C multiple HD44780 AVR Atmega library: This library implements a driver for HD44780 lcd connected through PCF8574 port expander. Data is transmitted using only 2 wire over i2c with the PCF8574. This library can drive up to 8 LCD concurrently. Lcd driver is based upon…
Source: An AVR Atmega library for multiple HD44780 based LCD connected through i2c