SPI(x1/x2/x4) NAND Flash

2G

35

14.5 Internal ECC

The serial device offers data corruption protection by offering optional internal ECC.READs and PROGRAMs with internal

ECC can be enabled or disabled by setting feature bit ECC_EN. ECC is enabled after device power up, so the default

READ

and PROGRAM commands operate with internal ECC in the “active” state. To enable/disable ECC, perform the

following command sequence:

• Issue the SET FEATURES command (1FH).

• Set the feature bit ECC_EN as you want:

1.

To enable ECC, Set ECC_EN to 1.

2.

To disable ECC, Clear ECC_EN to 0.

During a PROGRAM operation, the device calculates an ECC code on the 2k page in the cache register, before the page

is written to the NAND Flash array.

During a READ operation, the page data is read from the array to the cache register, where the ECC code is calculated

and compared with the ECC code value read from the array. If error bits are detected, the error is corrected in the cache

register. Only corrected data is output on the I/O bus. The ECC status bit indicates whether or not the error correction was

successful. The ECC Protection table below shows the ECC protection scheme used throughout a page.

With internal ECC, the user must accommodate the following:

• Spare area definitions provided in the ECC Protection table below.

• ECC can protect according main and spare areas. WRITEs to the ECC area are ignored.

Table14-6. ECC Protection and Spare Area

Min Byte Address

Max Byte Address

ECC Protected

Area

Description

000h

1FFh

Yes

Main 0

User data 0

200h

3FFh

Yes

Main 1

User data 1

400h

5FFh

Yes

Main 2

User data 2

600h

7FFh

Yes

Main 3

User data 3

800h

80Fh

Yes

Spare 0

810h

81Fh

Yes

Spare 1

User meta data 1

820h

82Fh

Yes

Spare 2

User meta data 2

830h

83Fh

Yes

Spare 3

User meta data 3

Note1:800H is reserved for initial bad block mark, and please check the initial bad block mark with internal ECC off.