Research And Realization Of Multi-protocol Building Automation Communication Platform

Building automation system is a major component of intelligent building. It is responsible for monitoring the status and parameters of field devices. Currently, the domestic devices of building automation are mostly produced by foreign manufacturers, and these products are basically all using their own bus standards such as:LonWorks, CAN, RS485, etc.. To solve the above situation, this thesis provides a building automation system integration scheme access Ethernet.In this thesis, the advanced ARM Cortex-M3core MCU STM32F107is taken as the main chip. Power supply circuit, clock circuit, reset circuit and JTAG emulation interface are designed with STM32F107as the core, extending the data storage and image display circuit, providing Ethernet, CAN, RS232/485and other bus interface. So, the hardware architecture of a building automation communications platform is set up.The embedded TCP/IP protocol stack LwIP is migrated to the communication platform. The function call processing among levels of the embedded TCP/IP protocol stack LwIP is elaborated in detail. On the STM32F107Ethernet driver is programmed and LwIP is run successfully.Embedded file system EFSL is migrated to the STM32F107. On the basis of LwIP, the file transmission is realized. Using the C#language Socket to write PC programs, the file can be uploaded and downloadde between the host computer and communications platforms. At the same time, the static web function is realized. The web can display baisic information of devices which are connected with communication platform.In order to meet the manual proofreading function of automatic reading system in the intelligent building, the JPEG encoding and decoding processes are reseached. Programming of TFT-LCD controller ILI9320driver is accomplished. To improve the speed of JPEG decoding on STM32F107, a simplified algorithm of inverse discrete cosine transform is used. The JPEG soft decoding is realized.CAN, RS232and RS485devices are connected with communications platform respectively. Programming of CAN and USART drive is accomplished, and the program of three kinds of bus to Ethernet data conversion is also written. Through the Ethereal packet capture software, that the data is successfully converted to Ethernet is verified.