基于PCI从工作模式的四串口板卡设计

With the application of computer systems and the development of communication networks, communication functions is increasingly more and more important. Commu-nication is both between the computers and peripherals, including information ex-change between computers.As series communication delivers message in a trans-mission line one bit by one bit,the number of transmission lines is less.And it can be used for information delivery by the existing telephone network,so it is particularly suitable for long-distance transmission.For those people-machine switching equip-ments not far away from computers and peripheral equipments serial-stored,such as,terminal,printer,logic analyzers,disk,it is also common by serial mode exchanging data.In regard to real-time control and management,in using more than one computer processors to control the distribution of the composition of classification systems,the communication between the CPUs are generally by serial methods .There-fore, serial interface is commonly used in computer interface applications.Many peripherals and computers communicate by serial manner, serial manner mentioned here refers to the transmission of information between peripherals and interface circuits.Actually,it is still working in parallel manner between CPU and interface.