PLC协处理器板的VME总线接口系统

总线接口系统是ＰＬＣ协处理器与宿主机之间交互的硬件通道。它的设计需要满足ＰＬＣ协处理器在交互作用方面的功能要求，同时要满足宿主机总线及操作系统在硬件和软件方面的各种协议。本文讨论了在ＳＵＮ－ＯＳ环境下，基于ＶＭＥ总线的数据传输，作为总线主设备的ＤＭＡ传输和从设备传输的优缺点。对传输速度进行了实验比较，确定了简洁可靠的方案。采用优化设计以及ＦＰＧＡ技术，实现了Ｐｒｏｌｏｇ／Ｌｉｓｐ协处理器板与Ｓｕｎ

THE VMEBUS INTERFACE SYSTEM OF A PLC COPROCESSOR BOARD

VMEbus interface system is the hardware channel which connects a PLC coprocessor board with a host machine. It should undertake the communication of the PLCboard, and cater to the various protocols which the bus and operating system of the hostmachine require on hardware and software. This paper compares the data transfer byusing the PLC board as the bus master device with DMA and the bus slave device without DMA under the circumstance of SUN OS and VMEbus. We tested the data transferrate, adopted the reasonable method, and implemented the VMEbus interface betweenthe PLC board and SUN3/SUN4 workstation by FPGA (Field Programmable Gate Array).