Universal Serial-Internet Switche Based On MC9S12NE64

Easy using, high reliability, strong enough communication capacity for industrial control equIPment, made serial communication been extensively applied in industrial and automation control area.Today, remote control has become a trend, the Internet of things is also on the agenda, so networking all electronic equIpments is imperative. But the transmission distance of serial communication is seriously hampering the remote controlling and serial data sharing of the equIPment. In order to overcome the limitation of transmission distance of serial communication, realizing quick networking of serial equIpments has become a key step for the Internet of things.The simpliest solution of realizing the quick networking of the serial port equIPment is serial-Ethernet switche, many businesses had invested to the researching and product development. From industry to commercial applications, from industry to commercial applications, there are corresponding products. But the price of most commercial serial-Ethernet switches are very high, it is difficult to realize the the wide application in low-end field. Based on the analysis of the existing commercial serial-Ethernet switches, this paper proposed a low cost solutions.The hardware platform using freescale's 16-bit single chIP MC9S12NE64, software development environment using MT-IDE For HCS12 integrated development environment. The system have no need to do any extension work because the hardware resources of the chIP is very abundant. This paper mainly realizes the transplant of the OpenTCP protocal. data retransmission between the Ethernet and the serial portthe system also achieved the online parameters modification, and automatically restart mechanism when system running error.At last tested the related functions of the system.The system first complete a series of initialization, and then start the server and enter into the main circulation. In the main circulation, after completing the data processing, the system enter into low power consumption mode-WAIT mode. In low power consumption mode, the CPU does not execute any instructions, only through interrupt will awake the system from this mode. At the same time, the system re-enter WAIT mode after data processed.Realization of the server mode, on-line modification of network parameters and serial interface communication parameters realized the basic functions of the system; Low-cost network chIP and reallization of WAIT mode meets low cost and low power consumption positioning; Zero copy characteristics of the openTCP protocal enhanced the realtime nature of the serial Ethernet switche. The maintenance of single connection for the system and the automatic restart mechanism made great comtribution to the stable running of the system. In general, the whole design achieved the requrements expected.