A while ago I received a couple of I/O port expander modules that use the I 2 C protocol. Using that Chinese module, you can use only the SDA and SCL pins of your Arduino, or any microcontroller ...

// Command Byte Codes See URL : dinceraydin.com/lcd/commands.htm for HD44780 CMDs #define LCD_MODE_8BIT 0x38 // Function set (8-bit interface, 2 lines, 5*7 Pixels) # ...