Design And Implementation Of 32×32 Digital Switch Chip Based On CPLD Used In VGA Switch Matrix

In recent years, with the development of social economic and the new safety demands of industry, video switch matrix has been widely used in surveillance, communications, electronic teaching, large screen display and other aspects. Switchers enable multiple video and audio signals to be selected and sent to one or more display devices. With the advent of the digital age, more designers turn to the research of digital video signal switching. For the designer, using low complexity, low cost design to achieve full featured video switch matrix is the ultimate goal. And CPLD has advantages of compactness, economy, high speed and modulization, so it is suitable for designers.According what was said above. This paper presents a new method of a 32×32 digital switch chip based on CPLD. The chip is a crosspoint array with 32 outputs, each of which can be connected to any one of 32 inputs. The chip is programmed in serial mode. This solution can significantly improve the complexity and cost of the switch matrix. MAXⅡCPLD is also enhanced the high-density products, power and cost advantages, so that MAXⅡCPLD can be used to replace the high-power and high-cost ASSP.Chip's design and implementation procedure of the scheme are detailed discuss in the paper, including software simulation, chip designing and PCB designing. And EPM1270T144C3 in MAXⅡfamily of Altera was used to complete the special component. The program was finished with VHDL in QuartusⅡcompiler. The overall and internal structure of the chip and the implementation of the chip were described in detail in the paper.The paper also designed and implemented a VGA32×32 video switch matrix, which was based on the digital switch chip designed in this paper. VGA switch matrix is widely used in various occasions which need VGA signal switching and choosing, such as:radio television, big screen TV, audio-visual education, video conference, multimedia conference, company meeting room, troops, government agencies, control center, classroom, hotels, home theater and video conference room. The overall structure, the PCB designing and the programs are detailed discussed in the paper. The chip's timing and use were discussed. A host computer control procedures were developed.The test has proved that this chip has good function and stability, using this chip can low complexity cost of the switch matrix. The system is characteristic of high integration, robustness and flexibility. It can be extended in industry.