Arduino Mega, ST7920 using COSA
The Cosa ST7920 library uses text mode only (16X4). The ST7920 class is controlled though an adapter. There are several adapters available depending on how you wish to connect to the Arduino. They range from parallel 4-bit to SPI with shift register. The adapters implement the interface HD44780::IO. There are several LCD examples. The CosaLCDbench shows the possible configurations with LCD and Adapters. Please see the file for further details.