The System Design Of CF Card Based On VxWorks

With the develepment of embedded system,embedded memory device become more and more important in the embedded system design.CF card is a kind of Flash memory.At present,CF card is very popular in the application of embedded system because it has much advantage,such as high-speed,large capacity and reliable.In order to using this memory device,it is necessary to realize its drivers and operating sytem interface.It will be best that application has nothing to do with the hardware to access the device.It shoule be different to realize the drivers depending on diffent cpu and hardware interface.At present,ARM9 is one of the most popular cpu because of its characteristic such as small volume,low power,low-cost,high performance.So far, ARM and its technic have being used in various fields such as industrial control, wireless communications,network application,consumer electronics products and so on.ARM9 is selected for this CF card system design because of its popular appliation and excellent characteristic.A excellent embedded design is not only depending on the hardware but also a good operating system and development environment.VxWorks is a kind of real-time operating system who has good reliability and excellent real-time and that is why it is used widely in communications,military affairs,aviation and some area who demand real-time seriously such as guided ballistic,aircraft navigation,satellite communications and so on.In addition,the friendly development environment,tornado brings greatly facilitated to the developers.The ultimate purpose of the underlying driver is to be called by the upper application.It is necessary to achieve the capability that it has nothing to do with the hardware when the application access the device.In this way,there is much advantage.First,the application developer don't need to know the difference of these devices.Second,it improves the portability of application code and saves a lot of project development time.VxWorks provides a file system TrueFFS,which can shield the difference of the bottom devices.When TrueFFS is achieved in CF card,the upper application will access the CF card just like the other normal flash device.In addition, the TrueFFS provide some algorithm to extend the life of flash card.This article is based on the project of on-board communications system.And it is designed to meet the demanding of the project.This system design take the ARM9200 as the hardware platform,VxWorks as the operating system,and achieve the TrueFFS on the CF card.Finally,the CF card is accessed by the application just like the other normal flash device.