A practical design of a synchronous video output system based on USB 2.0 protocol is introduced. The system adopts CYPRESS's FX2 USB controller, adopts GPIF mode, and the hardware design is simplified. It can output video images synchronously with the host according to the PAL TV standard. This article refers to the address: http:// In today's fast-changing information technology, people's demand for video image transmission is becoming more and more urgent, and the requirements are getting higher and higher. The bottleneck of the entire image transmission system is that the amount of information of the video image is large, and the delay in the transmission process is prone to occur. , jitter, distortion and other phenomena, so the choice of video image transmission bus requires high speed and low error rate. At present, the bus used for real-time transmission of video images mainly includes PCI, 1394 and USB. In comparison, the USB 2.0 high-speed transmission protocol combines the advantages of fast, universal, reliable, power-saving, and hot-swappable. It has more powerful versatility and flexibility than the traditional PCI-based, 1394-bus-based video output system. Sex. Especially in the case of using a portable device such as a notebook computer for video output, the synchronous video output system described in this paper is composed of a video output interface card as a peripheral device and an application software on the host computer, using a universal serial bus (USB). ) Realize the transmission of video image data, and synchronize the video display with the host according to the PAL TV standard, and the picture is smooth and clear. 1. Video output interface card hardware structure and working principle 1.1 Hardware structure of the video output interface card The block diagram of the video output interface card is shown in Figure 1. It consists of three parts: the USB interface chip of the built-in MCU, the image storage SRAM, and the D/A image output. The main functions of each part are: USB interface chip and host communication, the video image data of the host is written to the SRAM through the USB cable according to a certain timing; the SRAM chip is responsible for the storage of the digital video signal; the D/A image output part is the digital video signal Converted to analog video signal, output display according to PAL system. 1.2 Video image transmission and storage display The video image data of this system is transmitted via USB cable. The USB cable contains 4 wires: Vbus, D+, D- and GND. The data is differentially transmitted on the D+ and D- signal lines with a 480M high-speed signal, and the transceiver does not require an external circuit on the USB interface control chip. The USB interface part is the most important communication part of the system. The USB interface control chip uses CYPRESS's EZ USB FX2 series CY7C68013 chip. It integrates an enhanced 51 series MCU with 8KB of on-chip RAM, a 16-bit parallel address bus, an 8/16 data bus, an IIC bus, a 4KB FIFO memory, and a general-purpose programmable interface GPIF, serial interface engine SIE and USB transceiver. It is a complete solution for USB 2.0. 4 Conclusion For the actual output of video image synchronization output, the system adopts the high-speed protocol of USB 2.0 and the FX2 USB controller of CYPRESS to simplify the hardware of the USB device interface. The field sync signal introduced into the video display part triggers the data stream, and the video image display result standard smooth. The transmission speed of the video image of this system is strictly 50 fields/second according to the PAL system, and the interface speed of the GPIF is 24MB/s. In addition, the system is scalable, convenient and practical. With a little modification, any data can be imported from the host to the peripherals at a high speed. At present, the maximum speed can be up to 23MB/s. If you add a part of the video acquisition circuit, you can become a real-time video. system. Linear Stepper Motor,Linear Actuator Motor,Nema Stepper Motor,Linear Drive Motor Changzhou Sherry International Trading Co., Ltd. , https://www.sherry-motor.com