TFT display interface type

When designing a product, if you consider that the product needs to design a display screen, before selecting the display screen, you must first evaluate the interface type, speed, video memory, voltage and software support of the microcontroller to ensure that the hardware resources match the screen resolution, refresh rate, power consumption and other parameters. This will ensure that the system can run smoothly on the display screen.

Interface type compatibility

What display interfaces does the microcontroller support? SPI, I²C, 8080 parallel port, RGB, LVDS, MIPI, eDP.

Interface rate and bandwidth

Can the MCU's communication speed (maximum SPI speed, parallel bus bandwidth, etc.) meet the display's refresh requirements? Higher resolutions and deeper color depths require higher data transfer speeds. Insufficient speeds can cause refresh delays or slow data writing.

Software driver support

Is there a matching display driver library (such as ST7735, ILI9341, ST7789, etc.)? If not, you need to write the driver yourself, which increases the development difficulty and debugging cycle.

Mainstream interfaces

1. SPI: Usually it is a 4-wire mode (CLK/MOSI/MISO/CS). The advantage is that it occupies fewer PIN pins, with a pin count of 8-10 pins, but it is difficult to meet the requirements of high-resolution LCD screens and high refresh rates. The resolution is not higher than 480×800, and the transmission rate is limited by the clock frequency (such as 40MHz) and bit width.
2. MCUinterface: It is divided into 8080 mode. The bus width affects the rate (for example, 16-bit bus @ 50MHz ≈ 800Mbps). The resolution is not higher than 480×800. The refresh rate is not high for small-size LCD screens. The hardware debugging is relatively simple.
3. LVDS: This technology increases total bandwidth by using multiple channels (such as four pairs of differential lines). For example, a single channel of 1.6 Gbps x 4 = 6.4 Gbps. It supports higher-resolution displays and refresh rates, with resolutions of at least 1280 × 720, and is primarily used in medium- and large-sized industrial screens.
4. MIPI : Supports 1-4 channels (Lane), such as DSI v1.3 with 1.5Gbps per channel and 6Gbps per channel with four channels. By superimposing bandwidth through multiple differential channels, the resolution is not less than 380×400, supporting high refresh rate and low power consumption.
5. eDP：The version upgrade significantly improves the speed, such as eDP 1.4 supports 8.1Gbps/channel, and four channels can reach 32.4Gbps. Large size or high-resolution display screen, high bandwidth, strong anti-interference, but the circuit and cable costs are higher.
6. HDMI：Mainly used for external display devices, but most TFT LCD screens require additional adapters for these interfaces.

Interface Type	Resolution (excluding specific driver ICs)	Data format/channel	Clock rate	Maximum theoretical bandwidth	Typical application scenarios
MCU Parallel (8080)	No higher than 480X800	8-bit or 16-bit parallel bus	10–30 MHz bus clock	≈240 Mbps (16 bit×15 MHz)	Small size and low resolution screen (such as 1.4 inches to 2.8 inches)
RGB Parallel	No higher than 480X800	18-bit（6-6-6）或 24-bit（8-8-8）并行	Pixel Clock 25–65 MHz	≈1.56 Gbps (24 bit×65 MHz)	Medium to high resolution screen (such as 4.3-inch to 10.1-inch display)
SPI serial (4-wire)	No higher than 320X480	Single serial (1 bit)	30–80 MHz SPI clock	80 Mbps	Small size and low resolution screen (such as 1.4 inches to 2.8 inches)
MIPI	No less than 320X480	1–4 differential lanes, 8b/10b encoding	0.5–1.5 Gbps per lane	≈6 Gbps (4 × 1.5 Gbps)	Mobile phones, tablets, and high refresh rate screens larger than 3.5 inches
LVDS	No less than 1024X600	2–4 differential pairs, 7b/8b encoding	1.0–2.5 Gbps per pair	≈10 Gbps (4 × 2.5 Gbps)	Large-size industrial and automotive displays with 8-inch or larger displays
eDP	No less than 1024X720	1–4 differential lanes, 8b/10b encoding	1.62–2.7 Gbps per lane	≈10.8 Gbps (4 × 2.7 Gbps)	Laptops, ultra-high-resolution screens

The LCD screens produced by Hongcai Technology, with many years of manufacturing experience, strict ISO quality system, factory direct sales advantages and rich customization options, can not only meet the parallel interface requirements of high bandwidth, high brightness and high resolution, but also provide one-stop software and hardware technical support. It is an ideal choice for scenarios with strict requirements on project quality and cost.