描述
随着消费类电子产品包括PDA,MP3、智能手机等手持设备的市场需求逐步扩大,产品间的竞争也愈发激烈,降低产品的设计成本,提升产品的市场竞争力成为嵌入式系统开发者所面临的重大挑战。NANDFLASH和NORFLASH作为两种主要的非易失性存储器,被应用于各种嵌入式系统。其中NANDFLASH主要优点在于存储密度高、容量大,有更占优势的存储性价比。但是NANDFLASH由于其独特的页式读写方式,并不适合程序的直接执行。因此,从NANDFLASH启动需要片上存储器作为代码执行的中转区。本文所讨论的一种系统启动方式,是在缺少片上存储器支持的情况下,实现系统直接从NANDFLASH启动。论文中充分考虑了如何实现软、硬件之间的协同工作,以完成SOC系统的设计。
2NANDFLASH控制器的结构
本文所讨论的NANDFLASH控制器是针对一款基于ARM7TDMI的SoC芯片,该控制器在芯片中的位置如图1所示,作为AMBA总线上的一个从设备集成于AHB上。主要模块包括总线接口模块、FIFO缓冲模块、ECC编码模块以及逻辑控制模块。
欧美品牌停产的,常用的“PLC”备品备件
我司产品应用于以下领域:
1,《发电厂DCS监控系统》
2,《智能平钢化炉系统制造》
3,《PLC可编程输送控制系统》
4,《DCS集散控制系统》
5,《智能型消防供水控制系统》
6,《化工厂药液恒流量计算机控制系统》
7,《电气控制系统》造纸,印染生产线,变电站综合自动化控制系列
本特利,英维思,伍德沃德,福克斯波罗、西屋、瑞恩、施耐德莫迪康、ABB、AB、西门子、摩托罗拉、GE发那科、安川、博世力士乐,ACSO,力士乐等各大品牌的DCS系统配件,机器人系统配件,大型伺服系统备件。
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