The Differences Between MCU and RGB Interfaces

The Differences Between MCU and RGB Interfaces

Feb 14th 2023

The parallel interface is the most prevalent type of display interface consisting primarily of MCU and RGB. While RGB (Red, Green, Blue) is only found on TFTs, the MCU interface is available for use on a wide range of displays. A microcontroller unit, or MCU, operates by executing the software instructions stored in its non-volatile memory module. Because MCUs were ROM-based in the past, it was challenging, if not impossible, to remove the program data from them. As flash technology revolutionizes semiconductor technologies, MCUs start storing program instructions in inbuilt flash memory. The RGB interface is a specialized parallel interface that sends red, green, and blue data to each pixel in increments of up to 8 bits. The configuration and programming of the display will determine how many bits are delivered every clock cycle.

MCU interfaces come in two common configurations: Motorola-6800 series and Intel-8080. Read, write, and chip-select signals are used by MCU interfaces to communicate with address registers or display RAM. The MCU provides RGB signals straight to the display memory of the LCM, depending on the color depth (8, 9, 16, or 18-bit). The memory area that houses the displayed pixel data is known as the frame buffer. Smart displays have inbuilt frame buffers that are RAM-based. Every time the display has to be updated, the MCU display interface accesses the frame buffer. For the purpose of reading pixels from the display controller, the MCU interface advances through frames at an accelerated pace. Directly from the internal memory, it can display visuals and read and write data. In such display systems, MCU provides both timing signals and pixel data.

The RGB interface operates without any involvement from a frame buffer, in contrast to the MCU interface. The number of data pins used for each of the RGB signals might range from 16 to 18 or 24. The data is directly written to the device from the GPIO pins since RGB generally lacks internal DDRAM memory. In exchange for employing more data ports, this enables RGB to transport data more quickly than the MCU interface. For use cases primarily focused on videos, the RGB interface is ideal.

Deciding whether to use the MCU or RGB interface depends primarily on how the display will be used. The CPU and memory requirements depend on the interface being used. When selecting an interface, other aspects like pin availability and processing speed must be taken into account. High-performance programs can employ RGB, but doing so necessitates more pins, faster processing, and more memory. Given that it has an internal frame buffer and the ability to store memory, a parallel MCU can be an excellent choice for showing graphics. Due to less stringent timing requirements than RGB, the MCU interface is generally easier to use.

After breaking down these two technologies, it can be concluded that an MCU interface is better for displaying still images and are typically less expensive and offer greater flexibility, while an RGB interface is better for use cases in which videos or moving images are to be displayed. Regardless of your project’s intricacy, FocusLCDs can offer consultation and a diverse selection of affordable, high-quality components to ensure your project’s success.