Research And Implementation Of Embedded UClinux In The Automobile Communication System

Internet is applied very rapidly at extent and depth, and more and more digital products approached our life, as the progress of social, technical innovation, development of information technology, popularization of digital products. But the communication with each other of the cars has not done well all along. Most of the handy mobile digital products were made by the embed operation system, embed system is applied to the communication of the car is a excellent project based on the previous reason and taken account of the characteristic of the communication of the car. Embed system has many merits, such as volume is small, running stable, transplant robust. This paper described the development technology of the embed system, analysis of the embed core Linux and net technology of Linux with broadcast and multicast, implement of the embed communication of the car. Linux is the operation system that developed in the net. It was original by avocation of a Finland student Linux Torvalds. The development of the Linux is the fancy by the proficient of the programmer at the internet, so it has been mature stable soon operation system. It is merit that it can run at many operation systems, supports many hardware, such as X86, Alpha, ARM, NEC etc. it can cut out and performance is super excellence, the lower cost, mightiness function of net. most net protocol and interface can implement in the Linux, And take in and send out in large quantities of the net is good, and support of the GUI. Linux has performance excellent X Window system. It can develop GUI easily at the support of the X Window. Just so, it adapts for developing the embed system. We always use c or c++, because the development of the embed program in the Linux environment. Needing the GUN cross compile as follows: Gcc: compile, it c an make the cross compile format, namely it's binary file that can run at the host machine; Binutils: some aided tools, including objdump (binary file that can anticompile ), as (compile compile machine ), ld ( link machine) etc.. Gdb: debug machine, it can use many cross debug means. Gdb-bdm (background debug tools). The core of the embed uClinux is mostyl made of the five parts. 1. process scheme (SCHED) it controls the visiting of the process to cpu, UClinux uses simple process scheme arithmetic based on the priority. 2. memory manage (MM) memory manage permits many processes access share memory security. Process can not visit and access the memory page without the authorization. Core protects code and data of single process, so it can avoid other process edits it. 3. file system (fs) file system can divide into logic file system and program of the device driver.4. net interface (NET) It provides all sorts of the access of the net interface and supports hardware of the net. Net interface can divide into net protocol and net device driver. The part of the net protocol takes charge of the each net transfer protocol, net device driver takes charge of the hardware communication. 5. communication of the process (IPC) taking charge communication of the process is it's function. The mainly function of the core embed uClinux as follows: 1. Manage writing and reading of the file system, it maps the operation of the file system to the disc and other device. 2. run of the managing program, send the resources to the program, and dispose the communication of the process. 3. manage storage, allocate the memory to the program. 4. manage IO, map the device to the file. 5. manage communication of the net. Embed uClinux fully supports net transfer protocol such as TCP/IP. It can realize broadcast and multicast etc. as commonly says. The part of the net in this paper, we emphasis the difference communication between TCP and UDP, and enumerate the technical implements of all sorts of the communication protocols in the embed system. All in all, this paper emphasizes the technicalimplements of the communication of the car in the embed system. We have analysed thorough and intensive from the embed hardware designing to embed software designing to the designing of total communication of the car, particular describing the constitute of hardware, software and total design chart in the embed communication of the car. We also have particular discussed the voice technical in the corresponding chapter, and uncovered a serious problem, as uClinux is a time-sharing operation system, so it can not dispose the input of the voice real time. Improving the real time is a important work, at the same time, all sorts of the modules communicate harmony is also a important work, this is the work that we should work hard to hand it.