LCD CPU interface and RGB interface

Content Summary:At present, the general color LCD connection methods have so several: MCU mode, RGB mode, SPI mode, VSync mode, Mddi mode. MCU mode: Currently the most commonly used connection mode, is generally 80 system (68 system no longer exists). Data bits are transmitted in 8-bit, 9-bit, 16-bit, and 18-bit. Lines are divided into: cs/,rs (Register selection), rd/,wr/, and then the data line. The advantages are: simple and convenient control, no clock and sync signal. The disadvantage is: to consume gram, so it is difficult to do large screen (QVGA above).
RGB Mode: Large screen adopts more mode, data bit transmission also has 6 bits, 16 bits and 18 bits. Lines are generally: vsync,hsync,dotclk,vld,enable, the rest is the data line. Its advantages and disadvantages are exactly the opposite of MCU mode.
SPI mode: Use less, wired for cs/,slk,sdi,sdo four lines, less connection but software control is more complex.
VSync Mode: This mode is in the MCU mode to add a vsync (frame sync) signal line, applied to the motion picture update.
Mddi mode: The interface Mddi (Mobiledisplaydigitalinterface), introduced by Qualcomm in 2004, improves the reliability of mobile phones and reduces power consumption by reducing connections, which replaces SPI mode and becomes a high-speed serial interface in the mobile domain. Lines are mainly host_data,host_strobe,client_data,client_strobe,power,gnd. At present, Renesas and Samsung have only just shipped (mainly large screen).

By looking at the package interface diagram provided by the LCM module provider, we can see roughly what interface it provides, mainly based on the user's

Requirements to choose from.

There are many kinds of LCD interface, the classification is very fine. Mainly look at the LCD drive mode and control mode.

Generally can be divided into MCU interface and RGB interface.

The MCU interface can be divided into 8080 mode and 6800 mode, which is mainly the difference of timing. For RGB interface can be divided into analog RGB,ADC interface and digital RGB interface. As for the need not to HSNC,VSNC signal, this is in the RGB interface, but also to see what type of Control drive mode, you can not need.

MCU interface: Decoding commands, generating sequential signals by timinggenerator, and driving COM and SEG drives. RGB interface: When writing lcdregistersetting, there is no difference from MPU. The difference is only in how the image is written.

The MCU mode requires a WR,RD,RS,RESET,CS signal. RGB mode needs the signal has hsync,vsync,enable,cs,reset, some also need Rs.

In the MCU mode, because the data can be stored to the IC internal gram and then to the screen to write, so this mode LCD can be directly connected to the memory bus. RGB mode is different, it has no internal ram,hsync,vsync,enable,cs,reset,rs can be directly connected to the memory Gpio mouth, with the gpio mouth to simulate the waveform, but there are so many idle Gpio mouth is a matter to consider, In addition because it does not have RAM so the data is straight toward

The main differences are:

MPU Interface: Display data written to Ddram, often used for still picture display.

RGB Interface mode: Display data not written Ddram, direct write screen, fast, often used to display video or animation.

RGB interface only for TFT module