求助LPC1788用户手册的SDRAM错误
手册的第178页对EMC的address mapping是这样写的32 bit external bus address mapping (Row, Bank, Column)
1 0 000 00 16 Mb (2Mx8), 2 banks, row length = 11, column length = 9
1 0 000 01 16 Mb (1Mx16), 2 banks, row length = 11, column length = 8
1 0 001 00 64 Mb (8Mx8), 4 banks, row length = 12, column length = 9
1 0 001 01 64 Mb (4Mx16), 4 banks, row length = 12, column length = 8
1 0 001 10 64 Mb (2Mx32), 4 banks, row length = 11, column length = 8
1 0 010 00 128 Mb (16Mx8), 4 banks, row length = 12, column length = 10
1 0 010 01 128 Mb (8Mx16), 4 banks, row length = 12, column length = 9
1 0 010 10 128 Mb (4Mx32), 4 banks, row length = 12, column length = 8
1 0 011 00 256 Mb (32Mx8), 4 banks, row length = 13, column length = 10
1 0 011 01 256 Mb (16Mx16), 4 banks, row length = 13, column length = 9
1 0 011 10 256 Mb (8Mx32), 4 banks, row length = 13, column length = 8
1 0 100 00 512 Mb (64Mx8), 4 banks, row length = 13, column length = 11
1 0 100 01 512 Mb (32Mx16), 4 banks, row length = 13, column length = 10
32 bit external bus address mapping (Bank, Row, Column)
1 1 000 00 16 Mb (2Mx8), 2 banks, row length = 11, column length = 9
1 1 000 01 16 Mb (1Mx16), 2 banks, row length = 11, column length = 8
1 1 001 00 64 Mb (8Mx8), 4 banks, row length = 12, column length = 9
1 1 001 01 64 Mb (4Mx16), 4 banks, row length = 12, column length = 8
1 1 001 10 64 Mb (2Mx32), 4 banks, row length = 11, column length = 8
1 1 010 00 128 Mb (16Mx8), 4 banks, row length = 12, column length = 10
1 1 010 01 128 Mb (8Mx16), 4 banks, row length = 12, column length = 9
1 1 010 10 128 Mb (4Mx32), 4 banks, row length = 12, column length = 8
1 1 011 00 256 Mb (32Mx8), 4 banks, row length = 13, column length = 10
1 1 011 01 256 Mb (16Mx16), 4 banks, row length = 13, column length = 9
1 1 011 10 256 Mb (8Mx32), 4 banks, row length= 13, column length = 8
1 1 100 00 512 Mb (64Mx8), 4 banks, row length = 13, column length = 11
1 1 100 01 512 Mb (32Mx16), 4 banks, row length = 13, column length = 10
我的问题是
1。为什么会是同样是32位总线的，一种内存分成两个配置？
2。同样的bank,同样的row,同样的column,同样的32位数据宽度，为什么有不一样的容量？
1 0 001 00 64 Mb (8Mx8), 4 banks, row length = 12, column length = 9
1 0 010 01 128 Mb (8Mx16), 4 banks, row length = 12, column length = 9
3。容量计算与手册不符合，比如
1 0 010 01 128 Mb (8Mx16), 4 banks, row length = 12, column length = 9
按这个规格算出来的容量应该是256Mb才是正确。
4。1 0 010 01 128 Mb (8Mx16), 4 banks, row length = 12, column length = 9
这个例子中8M*16中的16代表何意？难道是指内存的数据总线宽度，但想想又不对啊，
这个明明是属于32 bit external bus address mapping 里的啊，怎么又变成16位的呢
迷糊求解。
没有用过这个片子，从上面可看出,32bit...这个指这个外部总线的名字，8MX16表示16位数据宽度，8MX8表示8位数据宽度
另，似乎手册中有提到sdram的CLK最高只能到80M？，属实？ 本帖最后由 lpc1788 于 2012-11-29 14:58 编辑
老兄，这是你完全不仔细造成的
32 bit external bus address mapping (Row, Bank, Column)
32 bit external bus address mapping (Bank, Row, Column)
看到问题没有，SDRAM有行列，你好好对比一下
1.一般我们都使用的是TSSOP54脚封的SDRAM内存，用两片16位总线的拼成一个32位的总线，但是内存还有一种是32位总线的，这个就不需要拼起来，并且几家大公司的有的内存还有些小区别有的。先行后块，先块后行等等.
2.你说的那个8M*16意思是8MBYTE*16总线位宽，意思就是8M字节的片子，总线宽度为16。OK？？？？？ lpc1788 发表于 2012-11-29 14:47 static/image/common/back.gif
老兄，这是你完全不仔细造成的
32 bit external bus address mapping (Row, Bank, Column)
谢谢。
32 bit external bus address mapping (Row, Bank, Column)
32 bit external bus address mapping (Bank, Row, Column)
这里的差别我也看到了，但下面的描述都完全一样的啊
还有32 bit external bus address mapping 不是指内存芯片的数据总线是32位的吗，怎么8M*16的也归类到里面？ 比如内存MT48LC8M32B2，它的规格是这样的
8 Meg x 32 (2 Meg x 32 x 4 banks)
我应该选哪一种配置呢{:dizzy:} 8 Meg x 32
Configuration 2 Megx 32 x 4 banks
Refresh Count 4K
Row Addressing 4K (A0–A11)
Bank Addressing 4 (BA0, BA1)
Column Addressing 512 (A0–A8) 这个要仔细的看看SDRAM的文档，而不是控制器的。 HoldMyARM 发表于 2012-11-29 16:39
8 Meg x 32
Configuration 2 Megx 32 x 4 banks
Refresh Count 4K
不知楼主搞明白了没，我对这块这正迷茫着那
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