There are many kinds of LCD interfaces, and the classification is very fine. Mainly depends on the LCD drive mode and control mode, the current color LCD on the phone generally has these types of connection: MCU mode, RGB mode, SPI mode, VSYNC mode, MDDI mode, DSI mode. MCU mode (also written as MPU mode). Only TFT module has RGB interface.

　　But more applications are MUC mode and RGB mode. The differences are as follows:

　　1. MCU interface: Will decode the command and generate timing signal by TIming generator to drive COM and SEG driver.

        RGB interface: When writing LCD register setTIng, there is no difference with MCU interface. The difference only lies in the way the image is written.

　　2. In MCU mode, the data can be stored in the internal GRAM of the IC before writing to the screen, so the LCD can be directly connected to the MEMORY bus in this mode.

　　In RGB mode, there is no internal RAM, HSYNC, VSYNC, ENABLE, CS, RESET and RS can be directly connected to the GPIO port of MEMORY, and the GPIO port can be used to simulate the waveform.

　　3. MPU interface mode: display data is written to DDRAM, which is often used for still picture display.

　　RGB interface mode: display data is not written to DDRAM, it is directly written to the screen, which is fast and often used for displaying video or animation.

　　The main differences between MCU interface and RGB interface are：

　　MCU interface method: Display data is written to DDRAM, commonly used for still picture display.

　　RGB interface mode: Display data is not written to DDRAM, but written directly to the screen, which is fast and often used for displaying video or animation.

　　MCU mode

　　Because mainly for the field of microcontroller in use, hence the name. The standard term for MCU-LCD interface is the 8080 bus standard proposed by Intel, so the I80 is used in many documents to refer to MCU-LCD screens. It can be mainly divided into 8080 mode and 6800 mode, and the main difference between these two is the timing. Data bit transfer is 8-bit, 9-bit, 16-bit, 18-bit, 24-bit. Connecting lines are divided into: CS/, RS (register selection), RD/, WR/, and then the data line. The advantages are: simple and easy control, no need for clock and synchronization signals. The disadvantage is: it consumes GRAM, so it is difficult to do large screen (above 3.8). For the MCU interface LCM, the internal chip is called 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.

　　The Driver IC of the MCU interface LCD is equipped with GRAM, and the Driver IC acts as a co-processor of the MCU, accepting the Command/Data sent by the MCU, and can work relatively independently. For the MCU interface LCM (LCD Module), the internal chip is called 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 dot, line, or frame clocks.

　　M6800 Mode

　　M6800 mode supports selectable bus width 8/9/16/18-bit (default is 8-bit). The actual design idea is the same as that of I80, the main difference is that the bus control read/write signal of this mode is combined on one pin (/WR), and a latch signal (E) is added for data bit transmission with 8-bit, 9-bit, 16-bit and 18-bit.

　　I8080 mode

　　I80 mode connection is divided into: CS/, RS (register selection), RD/, WR/, and then the data line. The advantages are: simple and convenient control, no need for clock and synchronization signals. The disadvantage is: it consumes GRAM, so it is difficult to do large screen (QVGA or above).

　　The standard name of MCU interface is I80, and there are 5 control pins for the pins:

　　CS chip select signal

　　RS (set to 1 for write data, set to 0 for write command)

　　/WR (0 for write data) Data command differentiation signal

　　RESET Reset LCD (reset with fixed command series 0 1 0)

　　VSYNC mode

　　This mode is actually the MCU mode with a VSYNC signal applied to the motion picture update, which makes a big difference from the above two interfaces. This mode supports the function of direct animation display, which provides a solution to achieve animation display with minimal changes to the MCU interface. In this mode, the internal display operation is synchronized with the external VSYNC signal. It is possible to achieve an animated display with a higher rate than the internal operation. However, due to the difference in its operation, this mode has a limitation on the rate, that is, the write rate to the internal SRAM must be greater than the rate at which the display reads the internal SRAM.

　　RGB mode

　　Large screens use more modes, data bit transmission also has 6-bit, 16-bit and 18-bit, 24-bit points. Connecting lines are generally: VSYNC, HSYNC, DOTCLK, CS, RESET, some also need RS, the rest is the data line.

　　MDDI mode (MobileDisplayDigitalInterface)

　　Qualcomm proposed the interface MDDI in 2004 to improve the reliability of cell phones and reduce power consumption by reducing the number of wires, which will replace SPI mode as the high-speed serial interface in the mobile field. The wires are mainly host_data, host_strobe, client_data, client_strobe, power, and GND.

　　DSI mode

　　This mode is a serial bi-directional high-speed command transmission mode, the lines are D0P, D0N, D1P, D1N, CLKP, CLKN.