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发表于 2006-6-30 19:12:00
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<P 0cm 0cm 0pt; TEXT-INDENT: 20pt; mso-char-indent-count: 2.0">“<FONT face="Times New Roman">FLASH</FONT>存储器”经常可以与“<FONT face="Times New Roman">NOR</FONT>存储器”互换使用。许多业内人士也搞不清楚<FONT face="Times New Roman">NAND</FONT>闪存技术相对于<FONT face="Times New Roman">NOR</FONT>技术的优越之处<FONT face="Times New Roman">,</FONT>因为大多数情况下闪存只是用来存储少量的代码<FONT face="Times New Roman">,</FONT>这时<FONT face="Times New Roman">NOR</FONT>闪存更适合一些。而<FONT face="Times New Roman">NAND</FONT>则是高数据存储密度的理想解决方案。</P><P 0cm 0cm 0pt; TEXT-INDENT: 20pt; mso-char-indent-count: 2.0"><FONT face="Times New Roman">NOR</FONT>的特点是芯片内执行<FONT face="Times New Roman">(XIP, eXecute In Place),</FONT>这样应用程序可以直接在<FONT face="Times New Roman">flash</FONT>闪存内运行<FONT face="Times New Roman">,</FONT>不必再把代码读到系统<FONT face="Times New Roman">RAM</FONT>中。<p></p></P><P 0cm 0cm 0pt; TEXT-INDENT: 20pt; mso-char-indent-count: 2.0"><p><FONT face="Times New Roman"></FONT></p></P><P 0cm 0cm 0pt; TEXT-INDENT: 20pt; mso-char-indent-count: 2.0"><FONT face="Times New Roman">NOR</FONT>的传输效率很高<FONT face="Times New Roman">,</FONT>在<FONT face="Times New Roman">1</FONT>~<FONT face="Times New Roman">4MB</FONT>的小容量时具有很高的成本效益<FONT face="Times New Roman">,</FONT>但是很低的写入和擦除速度大大影响了它的性能。<p></p></P><P 0cm 0cm 0pt; TEXT-INDENT: 20pt; mso-char-indent-count: 2.0"><p><FONT face="Times New Roman"> </FONT></p> <FONT face="Times New Roman">NAND</FONT>结构能提供极高的单元密度<FONT face="Times New Roman">,</FONT>可以达到高存储密度<FONT face="Times New Roman">,</FONT>并且写入和擦除的速度也很快。应用<FONT face="Times New Roman">NAND</FONT>的困难在于<FONT face="Times New Roman">flash</FONT>的管理和需要特殊的系统接口。</P><P 0cm 0cm 0pt; TEXT-INDENT: 20pt; mso-char-indent-count: 2.0">外设是为了增加容量,如满足用户MP3,MP4等大容量,而增加的。</P><P 0cm 0cm 0pt; TEXT-INDENT: 20pt; mso-char-indent-count: 2.0"><p></p> </P>[br]<p align=right><font color=red>+1 RD币</font></p> |
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