WH2004D series are 20×4 character display modules which are built in with ST7066 controller IC; its default interface is 6800 4/8-bit parallel. The LCD module 20×4 displays are also available in SPI and I2C interface by using RW1063 controller IC. WH2004D is available in several different backlight colors including blue, green, white, yellow-green, amber, red and white LEDs. There are different character fonts/texts available for ST7066 IC including English/Japanese, English/West European, English/Scandinavian European, or English/Cyrillic (Russian) as options.
There are different interface options for WH2004D series, details as below:
►WH2004D : 6800 interface (ST7066 IC)
►WH2004D1 : SPI interface (RW1063 IC)
►WH2004D2 : I2C interface (RW1063 IC)