The Design Of Discrete I/O Module Based On Network Interface

In order to meet the demand for discrete signal acquisition, processing and outputting, a discrete I/O module based on a network interface is designed in this thesis, which can be used in the field of computer automatic measurement, aerospace monitoring and industrial automatic control. This module can not only drive the external devices through 96 output channels but also can detect 96 discrete input signals, which can be sent to the PC side through the Local Area Network(LAN).This thesis takes the SOPC embedded technology as the integral design method,which integrates the processor, memory and various interface modules into a single FPGA chip. The hardware design realizes the Nios II processor system by using the Nios II core processor, SRAM controller, EPCS controller, DM9000 A controller, PIO modules, JTAG modules and so on. Only on this system can the embedded software being buidt.The whole software design can be divided into two parts, one part is the embedded software and the other part is based on PC, both of which communicate with each other by way of reply. The embedded-side programming mainly contains the network interface driver transplantation, server network communication function realization and algorithm design of discrete IO module. Moreover, the other side focuses on analyzing the algorithm of each function module, socket application programming algorithm, and human-computer interaction interface.In order to ensure the stability and reliability of the network communication, the design takes control code verification mechanism into account. The discrete I/O module can also modify the static IP and control deferent devices through LAN.Finally, according to the design requirements, a multicast network environment should be built to test the function of discrete IO module. The result shows that multiple discrete IO modules can work stablely and can complete the design requirements such as real-time acquisition, outputting and self-detection. Moreover, the modularization method used in this paper can strongly increase the versatility and portability of our system, and has reference value to the development of other similar modules.