I am presently working on replacing the nand chip, where the oobsize has changed from x to y. This means that ecc also changes. Can anyone guide me what ecc is? What is OOBSize in nand chip, how are they related? there significance. I am a newbie, so please guide me here. Thanks in advance.
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Study the datasheet for the NAND chip. ECC is error correction code, typically BCH. The NAND chip will require an ECC capable of correcting up to N bits per block size of X bytes. The OOB (out-of-band area) is additional storage area (for storing the ECC bytes) associated with each data block. The ECC bytes are typically stored at the end of the OOB, so the size of the OOB and the length of the ECC determines the salient ECC offset value. – sawdust Jul 10 '20 at 08:23
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Do not confuse the correction capability of an ECC (number of **bits** per X bytes) with the *length* of the ECC (a number of bytes). The expression *"4-bit ECC"* actually refers to an ECC that has correction capability of 4 bits. Such an ECC using BCH for a 1024-byte block would be 7 bytes long. – sawdust Jul 10 '20 at 08:35
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Thanks sawdust, but when i refer the datasheet there is no mention of the ECC. Can u please suggest some links where i can have a better understanding of it. – Napster92 Jul 10 '20 at 14:19
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As u said, the ecc bytes are stored at the end of the oob area. Then what is stored in the OOB area. Can u please explain. – Napster92 Jul 10 '20 at 14:34