LCD interfaces

LCD interfaces come in a variety of categories. It mainly depends on the driving mode and control mode of LCD. Currently, the connection mode of color LCD on mobile phones is generally as follows: MCU mode, RGB mode, SPI mode, VSYNC mode, MDDI mode and DSI mode. MCU mode (also written as MPU mode). Only TFT modules have RGB interfaces.

MCU mode

It is named because it is mainly used in the field of single chip microcomputer. Later, it is widely used in middle and low-end mobile phones, whose main feature is cheap price. The standard term for the MCU-LCD interface is Intel's 8080 PCI, hence the I80 used in many documents to refer to the MCU-LCD screen. It can be divided into 8080 mode and 6800 mode, which are mainly different in timing. Data bit transfers are 8, 9, 16, 18, and 24 bits. The connection line is divided into CS/, RS(register selection), RD/, WR/, and then the data line. Advantages: the control is simple and convenient, no clock and synchronization signal. Disadvantages: GRAM consumption, so it is difficult to achieve a large screen (3.8 +). For an MCU interface LCM, the chip inside is called an LCD driver. The main function is to transform the data/commands sent by the host into RGB data for each pixel to be displayed on the screen. This process does not require a point, line, or frame clock.

MCU interface LCD DriverIC with GRAM, DriverIC as a PIECE of MCU coprocessor, accept MCU sent over the Command/Data, can be relatively independent work. For the MCU interface LCM(LCD Module), its internal chip is called the LCD driver. The main function is to transform the data/commands sent by the host into RGB data for each pixel to be displayed on the screen. This process does not require a point, line, or frame clock.

VSYNC mode

This mode is essentially a VSYNC signal added to the MCU mode for moving image updates, which is quite different from the above two interfaces. This mode supports the function of direct animation display. It provides a solution to realize animation display with minimal changes to the MCU interface. In this mode, internal display operations are synchronized with external VSYNC signals. Animation can be displayed at a higher rate than internal operations. However, due to the different way of operation, this mode has a rate limit, that is, the internal SRAM write rate must be greater than the display read internal SRAM rate.