Uart and parallel port are two opposite concepts, just like single-lane and multi-lane. Uart communication transmits each byte of data to the other end of the data line in a bitwise manner. In contrast, parallel port, as the name suggests, is parallel transmission of data to the receiving end, but it does not run multiple uart protocols at the same time. In fact, data transmission in uarts is much more complex. Parallel port and uart are completely different transmission methods. Generally, in digital circuits, if a 800*480 full-color real-time image reaches more than 30 fps, the data transmission must use parallel port communication, and the data capacity of uart communication cannot be compared with that of parallel port, such as reversing image application. Generally speaking, the design of single-color uart screen will use IIC or TTL, while the interface of color uart screen may be very diverse, and customized interfaces may be used according to different situations.
So why not replace all uarts with parallel ports? One reason is that parallel ports are more expensive, but this is not the main reason. In digital circuits, there are only two voltage logic levels, 1 and 0, and only direct current can be used. This makes long-distance transmission difficult, as direct current signals decay faster during transmission and signal compensation is required. If parallel ports are used, signal compensation will be more expensive.
The performance of the upper single-chip determines the choice of parallel LCD screen. 8-bit single-chip is suitable for 256-color display, while 16- and 32-bit single-chip can achieve 65K colors;
The color of the uart LCD display is not related to the upper single-chip, and generally can display 65K colors.
The writing speed of the parallel LCD screen is determined by the speed of the upper single-chip. The faster the speed of the upper single-chip, the shorter the writing time;
The read and write speed of the uart LCD screen is not related to the speed of the upper single-chip, but mainly related to the baud rate of the uart. The higher the baud rate, the faster the read and write speed.
The uart LCD screen mainly includes a uart communication device, Flash controller, LCD display controller, SDRAM controller, bus controller, etc. It receives instructions sent by the upper computer through the uart, and executes corresponding display operations after translation. Images and font libraries are pre-saved in Flash and can be called directly;
The parallel LCD screen mainly consists of an LCD display controller, SDRAM controller, parallel port controller, etc. Under the clock control, the agreed data sent by the parallel port is temporarily stored and displayed. That is to say, whatever information is sent, what content is displayed.
uart LCD screens are suitable for products with colorful, complex displays and many texts, but low-performance upper computers. UART screens are used in a variety of applications, including gaming systems, medical equipment, and industrial equipment. When purchasing a UART screen, it is important to consider the type of application it is being used for, as well as the size and resolution of the display. For cost-effective solutions, wholesale LCD module may be purchased in bulk at discounted prices.
Parallel LCD screens are suitable for products with simple interfaces, real-time data acquisition and display, and high-speed drawing. This type of connection is becoming increasingly rare, as other types of ports are replacing the parallel port. However, these types of screens are still available, and they are typically used in industrial applications. One example is the 7 inch TFT screen, which is a type of LCD that offers a high resolution image and a wide viewing angle. This type of LCD is often used in industrial settings, such as factory automation and medical imaging.
Through the above analysis, although the price of parallel LCD screens is cheaper than that of uart LCD screens, the effect is also obvious, and uart LCD screens are more competitive in the market.