Every LCD or OLED screen has an IC bonded to the panel ... SPI and I2C displays differ in their wiring. I2C displays rarely ever need anything other than SDA and SCL. Here’s one exception ...

Inexpensive OLED displays with I2C interfaces abound, but there is a catch: they tend to be stuck on I2C address 0x3C. Some have a jumper or solder pads to select an alternate (usually 0x3D), but ...