A Study Of Boot Technology Based On NAND Flash In Embedded Router

With the development of widely used electrical appliances,mobile phones and a variety of special equipment,and embedded processors,embedded hardware and software systems,embedded technology has become a popular technique.Especially with the embedded technology is widely used in various consumer electronics products as well as more complex system design,data storage and management for embedded systems has become an important research and application of hot spots.N AND Flash has a high storage density,low power,low cost,etc.and therefore is widely used in embedded systems.This paper focuses on the research of NAND Flash as Boot Flash applications in embedded router.First introduces key technology involved in the guidance system startup scheme,including the commonly used memory technology,Bootloader,NOR Flash boot process and management of bad blocks,combined with NAND Flash works,then design the NAND Flash module according to the NAND Flash module demand in the system.The main results achieved are as follows:1.Studying the NAND Flash balancing algorithm used in research to extend the life.In this paper,analyzing the NAND Flash life in the course of bad blocks.Because of NAND Flash process,making each Bit only from 1 to 0,so you must first erase operation before programming operation.It will cause a bad block in advance in some block on which frequently performed erase operations because of limited erase cycles,shorten the life of NAND Flash,which does not guarantee reliable system startup.In order to effectively extend the life of NAND Flash,this paper studies equalization algorithm.Since NAND Flash is mainly used to store bootloader in the system,and the bootloader is rarely updated,CPU only read the boot program from NAND Flash when the device is powered on or restarted,so the boot program is similar to the static files.In order to effectively extend the life of NAND Flash,the system uses a static balancing algorithm.Finally,analysing performance after using the equalization algorithm in the system.2.Discussing limited size of Stagel in Bootloader.In this paper,analyzes the existing NAND Flash boot method and apparatus in embedded router.One solution is that the CPLD acts as adapter between CPU and NAND Flash interface,Another solution is using first block of NAND Flash to store Stagel in boot program owing to the features of safety and with the subsequent use does not produce bad blocks in first block,the remainder are stored in a continuous block by multiple storage of NAND Flash after the first one.There are defects int the two existing programs,the first option is more complex of designing and relatively high cost for using CPLD as IO port for transferring.While the second formula,due to fixed NAND Flash block size,with the follow-up system or memory upgrades or needs to be updated the executable program in case of new system function,it may not be sufficient to store Stagel part of the boot process,and will result in the system updating.failure.Based on the analysis of existing problems,proposes an improved and reliable solutions,and consider the improved method and apparatus for booting the system on NAND Flash-based.Finally,explain the improved method and apparatus for guiding.The test results verify the idea of the system and prove that the system is available.