Ecc Parity Conversion Code Guide For 8/12/16-Bit Ecc - Samsung S5PC110 Manual

S5PC110_UM

4.3.11 ECC PARITY CONVERSION CODE GUIDE FOR 8/12/16-BIT ECC

The ECC parity conversion codes are there to fix errors, which occur when reading a free page. Free page means
the page erased. The 8/ 12/ 16-bit ECC modules support variable message size for meta data stored in spare
area. Generally, the size of main data (sector) is 512-byte and user should set the corresponding ECC parity
conversion codes as shown in Table below.
ECC type
8-bit ECC
12-bit ECC
16-bit ECC
The message size for meta data stored spare area can be different depending on user's needs. Hence, you can
change the size of meta data by changing MsgLength(NFECCCONF[25:16]) and change ECC parity conversion
codes.
Steps to know ECC parity conversion codes according to the size of message length:
1. Clear all ECC parity conversion registers (NFECCCONECC0 ~ NFECCCONECC6) as all zero.
2. Set all registers for page program
3. Reset InitMECC (NFECCCONT[2] bit as '1'
4. Write '0xff' data as much as the size of meta data.
5. After you write data as MsgLength(NFECCCONF[25:16]), the EncodeDone(NFECCSTAT[25]) is set as '1' and
generates the corresponding ECC parity codes.
6. Set ECC parity conversion registers as inverted values of ECC parity codes generated.
For testing if these ECC parity conversion codes work well, repeat step 3 ~ 5. After you set ECC parity
conversion codes, if the generated ECC parity code are all '0xff', then it is working correctly.
Constraints to support free page function:
−
Free page check is for only data area (512-byte)
−
If there is an error during reading a page erased (free page), then free page engine indicates that the
page is not free page.
−
To detect error(s) on free page, user should set corresponding conversion codes.
Here, 13 byte ECC parity conversion codes
Here, 20 byte ECC parity conversion codes
Here, 26 byte ECC parity conversion codes
ECC Parity Conversion Codes
4 NAND FLASH CONTROLLER
4-12