SPI is used for LCD display, and I2C is used for touch. The touch screen is controlled by the chip on the motherboard, which significantly reduces cost..It is connected to the motherboard through the FPC cable, simple and convenient.Designed with XH2.54 terminal, which can communicate with the board through the terminal.Note: If you have CB1 V2.1, you need to select Type 2: TFT35SPI V2.1+IO2CAN V1.0If you have CB1 V2.2, TFT35SPI V2.1 can be use directlyBrief Introduction: TFT35 SPI V2.1 is a medium-size and clear 3D printer display developed by the 3D printing team of Technology Co., .Item Type: Display ScreenModel Number: TFT35 Touch ScreenProduct name: TFT35 SPI V2.1 Touch ScreenProduct Dimensions: 98 x 56mmInput Voltage: DC 5V Voltage: VoltageScreen Size: 3.5-inchResolution: 480x320Interface: SPII2CIf you need other resources for this product, visit https: //github.//Colour:blackMaterial:plastic+metaltype: APackage Contents:1 x TFT35 SPI V2.1 Touch ScreenOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.