LCD RGB interface and MCU interface differences

At present, the general color LCD connection mode has so many: MCU mode, RGB mode, SPI mode, VSync mode, Mddi mode and so on.

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First, the hardware interface

MCU mode: currently the most commonly used connection mode, usually 80 system (68 system no longer exists). Data bits are transmitted in 8-bit, 9-bit, 16-bit, and 18-bit. The connection is divided into: cs/,rs (Register selection), rd/,wr/, and then the data line. The advantages are: control is simple and convenient, no clock and synchronous signal. The disadvantage is: to consume gram, so it is difficult to achieve large screen (QVGA above).

RGB Mode: large screen with more modes, data bit transmission also has 6 bits, 16 bits and 18 bits of points. Wiring generally has: vsync,hsync,dotclk,vld,enable, the rest is the data line. Its advantages and disadvantages are just the opposite of MCU mode.

SPI mode: using less, wired for cs/,slk,sdi,sdo four lines, less wiring but software control is more complex.

vsync mode: This mode adds a vsync (frame sync) signal line in MCU mode, which is applied to the motion picture update.

Mddi mode: Qualcomm's Interface Mddi (mobile Display Digital Interface), introduced in 2004, improves mobile phone reliability and reduces power consumption by reducing wiring This replaces the SPI mode and becomes the high-speed serial interface of the mobile domain. The connection is mainly host_data,host_strobe,client_data,client_strobe,power,gnd several wires. Currently Renesas and Samsung are only just shipping (mainly large screen).

By observing the package interface diagram provided by the LCM module provider, we can see what interface it provides, mainly according to the user's requirements.

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Second, LCD RGB&MCU Driver analysis
LCD has a variety of interfaces, the classification is very fine. Mainly look at the LCD drive mode and control mode. Can be roughly divided into MCU interface and RGB interface.

For the MCU interface can be divided into 8080 mode and 6800 mode, this is mainly the difference between timing.
For the RGB interface , it can be divided into analog RGB, ADC interface and digital RGB interface. As for the need to not need HSNC,VSNC signal, this is in the RGB interface, but also depends on the use of what kind of control drive mode, also can not be required.

MCU interface : Decodes the command, generates a timing signal from the timing generator, drives the COM and SEG drives.
RGB Interface : When writing LCD register setting, 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 requires the signal to be hsync,vsync,enable,cs,reset, some also need Rs.

In MCU mode , since the data can be stored in the IC gram and then to write on the screen, so this mode LCD can be directly connected to the memory of the bus.
The RGB mode is different, it has no internal ram,hsync,vsync,enable,cs,reset,rs can be directly connected to the memory of the Gpio port, with a GPIO port to simulate the waveform, But there are so many idle gpio ports to consider, and since it does not have RAM, the data is written directly to the screen.

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Three, the main difference is:

MPU interface mode: Display data write Ddram, often used for still picture display.

RGB Interface mode: Display data is not written to Ddram, direct writing screen, fast, often used to display video or animation. Only the TFT module has an RGB interface.

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Note:

Made a simple change, the original source: Http://hi.baidu.com/lcdbbs/item/822d08df2b3f77e955347ff6