Remote Embedded Monitor System Based On S3C2410

With the rapid development of multimedia, network and embedded technique, itbrings manyapplications relatedwithembeddedinternet monitormoreandmore. Inthefield of technique monitor, after the system having experienced some systems, such aslocal simulation signal monitor system, pc card based digital monitor system andembedded technique based network digital monitor system, the video monitor has atendencytobeasystemintegratedonthehead,videodigitalizedmonitornetworkbased,system integrated. It has become a tendency that converting the video monitor fromanalogsignalintodigitalsignalandleadingittobewithnetworkanytimeandplace.In the embedded field, embedded linux has become the mainstream operatingsystem. Embedded linux which can be applied on many kinds of platforms is opensource and free software. Itself can support strong network function and possessesnumerous software resource. It is the development of embedded linux that makes itpossible to empolder IPCAM, a high capability and low cost embedded equipment.IPCAM, which consists of camera and embedded development platform, is anembedded system, and it has the network function. The exploitation of embeddedsystemisbasedonembeddedhardwareplatformandembeddedoperatingsystem.Relied on the linux open sources and free softwares, it trys to give a solution to anetwork video collecting device for general using. To carried on the analysis accordingtotheARM9built-insystemoflinux.It givesinthepaperthetotaldesignprojectofthesystem,architecture of software and hardware, workflow of system. Carried on thethorough research on the USB interface camera driver principle and designed it. Thedesign of USB interface camera driver follows the standard of USB device driver. Itmainly consists of two steps, registration of device driver and realization of thefunctions in the struct file_operations. It gives the function of these functions. Carriedoutvideocaptureprogrambasedonthisdriverandv4l,whichiscompiledinthepatternof build-in or module in the linux kernel for video and radio program, is standard interface. V4l consists of a series of APIs and images, radio card driver. It can sendorders or set parameters to the video device through the ioctl function. The videocapture program mainly contains opening the video device, modifying parameters ofimage attributes and image window and mapping data from kernel space to user spaceand so on. For the supportingof network remote monitor, a web server was installed onthe s3c2410 platform and webcam player program was compiled. The program iscompiled in applet pattern and is embedded in the html scripts. The webcam playerprogram can obtain the host name and port of video capture server from html by thefunction getParameter. Applet program connects the server, get data from the server inthe stream format and show the image real time. To support the access the local file, itusedthepolicyofthemechanismofdigitaljarsigner.Samsung s3c2410 microprocessor is used in our platform, which supplys richresourceandexternalresourceandithasbecomeastandardplatformsupportedbylinux.Eversinceversion2.6.10,linuxcanrunonitafterfewmodification,whichjustprovidenecessaryinformationabout nandflash tokernel.Tomakelinux configuration properly,thestandardconfigurationofSMDK2410canhelpalot.Different embedded platforms have not the same hardware resource. In general, itis the bootloader that takes the task of initialization of hardware and boots kernel.Bootloader is closely related to the hardware platform. After finishing the initializationof hardware, copying linux kernel to partition of sdram memory and preparing bootingparameters, bootloader jumps to the start address of linux kernel. Vivi that can bedownloadedfrom official websit ofSamsungis usedinthis paper.Modifyingthe fileofMakefile, assigning the place of the cross-compile tools and head file of linux kernel.Meanwhile setting partitions information of nand flash in the arch/arm/s3c2410.c file,and parameters for the linux kernel booting was setted as follows: linux_cmd_ line[] ="noinitrd root=/dev/ mtdblock2 init=/linuxrc console=ttySAC0, 115200". Mtdblock2means that it is the third partition of nand flash. It is rootfs in this paper. The string of"console=ttySAC0, 115200"means that the information of booting linux kernel isoutput to com0 and rate is 115200bps. Com0 port has been renamed ttySAC0 in linux2.6,but this hadnoinfluenceon com programminginthe user space andwe couldstilluse/dev/ttyS0.Embedded file system is usually constructed on flash memory, which makes thelinux traditional file system like ext2 unsuitable. Special file system is needed.According to system's requirement, Cramfs is finally choosed as system's booting filesystem. Cramfs is designed by Linus Torvalds, the founder of linux, and is acompressable and read only file system. Cramfs has a compressed rate up to 2:1, somore memory can be left for system. The read only characteristic prevents files fromdestroyingandisgoodforimprovingsystem'sreliability.Cramfscanreachahighspeedwhen read and write. After adding kernel image and user application on booting filesystem,theembeddedsystemissuccessfullyconstructed.