NAND FLASH纠错

huyongwei01

讨论：在进行nand flash纠错的时候，一般会把纠错码放在冗余区还是哪里？如果放在冗余区，如果冗余区发生bit错误，是否会损坏纠错码？这个问题怎么规避？

vasya

Frankly speaking you can place ecc bits whenever you want in the page (page here = data bits + redundancy bits since nand cells are all equal). LDPC based on Tanner graph which cover all bits in the page equal. ECC position in the page can be chosen based on an error pattern expected.

vasya

Frankly speaking you can place ECC bits wherever you want in the page (page = data bits+redundant bits). LDPC code based on Tanner graph (https://en.wikipedia.org/wiki/Tanner_graph) that equally protect both the data bits and ECC bits (see Tanner graph picture).

vasya

Frankly speaking you can place ECC bits in any position in the page (page here is data + redundant bits for ECC).
Since LDPC code is mesh tanner graph (https://en.wikipedia.org/wiki/Tanner_graph) both data and redundant bits are equally protected.

435661979

1.纠错码放冗余区;
2.冗余区出错不会损坏纠错码;
3.不用规避,BCH和LDPC不仅可以纠信息位,还可以纠冗余位,数学上已经保证了,纠错码纠错能力够就行.

kka

若nand flash 的一個page size 是 2112 byte.  2048 (data) + 64 (ecc) =  2112
64 byte 的ECC 就是由前面2048的data所運算出來的

南宫恨

回复 1# huyongwei01


    一般是放在冗余区，当然你得先看看是不是坏页，总之是正常数据加纠错码填满整个区域，之前了解过nand controller，当然ecc算法那部分我没看懂，但是我做的时候是让数据和Ecc填满一page，ecc就放到冗余区