嵌入式NAND FLASH读写.doc

NAND FLASH 读写
一、实验目的
。
FLASH 与NOR FLASH的区别。
FLASH的方法。
二、实验内容
,编写44B0的I/O驱动程序,结合NAND FLASH读写程序,完成对NAND FLASH的读写,并通过串口调试工具对NAND FLASH进行命令控制以及回显从NAND FLASH读取的数据。
三、预备知识
,编写和调试程序的基本过程。
。
FLASH的工作原理。
44B0数据手册中的I/O控制介绍。
FLASH K9F5608数据手册。
四、实验设备及工具
硬件:ARM嵌入式开发板、用于ARM7TDMI的JTAG仿真器、PC机Pentumn100以上
软件:PC机操作系统win98、Win2000或WinXP、ARM 集成开发环境、仿真器驱动程序、PC串口调试工具、实验原理及说明
五、实验原理
vs. NOR
Beside the different silicon cell design, the most important difference between NAND and NOR Flash is the bus interface. NOR Flash is connected to a address / data bus direct like other memory devices as SRAM etc. NAND Flash uses a multiplexed I/O Interface with some additional control pins. NAND flash is a sequential access device appropriate for mass storage applications, while NOR flash is a random access device appropriate for code storage Flash can be used for code storage and code execution. Code stored on NAND Flash can't be executed frome there. It must be loaded into RAM memory and executed from there.
NOR
NAND
Interface
Bus
I/O
Cell Size
Large
Small
Cell Cost
High
Low
Read Time
Fast
Slow
Program Time single Byte
Fast
Slow
Program Time multi Byte
Slow
Fast
Erase Time
Slow
Fast
Power consumption
High
Low, but requires additional RAM
Can execute code
Yes
No, but newer chips can execute a small loader out of the first page
Bit twiddling
nearly unrestricted
1-3 times, also known as "partial page program restriction"
Bad blocks at ship time
No
Allowed
Some facts about write speed.
NAND is typically faster than NOR for large writes. A typical NOR write is 10uS
per word, which results in 1280uS per 512 bytes on a 32-bit bus. A typical NAND write
is 50nS per byte + 10uS page seek + 200uS program which results in 236uS per 512
bytes on a 8 bit bus.
As NAND Flash is cheaper t