Abstract:

In order to realize online monitoring of the new Programmable Logic Controller based on Field Programmable Gate Array (FPGA based PLC), a broader approach employed FPGA technology for debuging embedded SoC (System on Chip) was introduced. A monitoring system which composed of ModBus module and Double RAM (DRAM) module primary was designed on FPGA chip to improve data communication efficiency between target SoC and monitor terminal. The monitoring system realized ModBus-RTU communication on the basis of UART, and the status data transmitted to PC through serial port. The DRAM module was shared by target SoC and PC, and the data exchange was realized by using the interrupt mechanism. By applying the proposed approach, the communication time that the target CPU spended in handling monitor procedures can be shortened to 0.002%, which ensures the real-time performance of monitoring data transmission and improves the control performance of SoC. The precept's feasibility was verified on Altera's FPGA chip.

摘要：

针对基于现场可编程门阵列(FPGA)的新型可编程逻辑控制器(FPGA based PLC)的在线监控问题，提出了泛化的基于FPGA技术对嵌入式片上系统(SoC)进行在线监控的方法。该方法设计了一个FPGA片上通信系统，系统内部固化基于UART的ModBus通信协议栈，通过串口与计算机上位机进行通信；采用双口RAM(DRAM)作为与监控对象间共享的数据缓存区，通过中断机制实现缓存数据的同步交换。性能分析结果表明，该方法将SoC处理监控通信的时间百分比降低至0.002%，确保了监控数据传送的实时性，且使SoC能够获得更佳控制性能。在Altera的cycloneⅡ系列芯片开发板上验证了方案的可行性。