init-033
Read invalid blocks
information
Read 1 and 2
page spare
sectors
st
nd
Invalid block
information
±
0xFF (or 0xFFFF for
16-bit devices)
Yes
No
Set invalid block flag
Clear invalid block flag
For first 4 blocks
Public Version
Device Initialization by ROM Code
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Table 26-35. Bad Block Mark Locations in NAND Spare Areas
Small Page NAND
Large Page NAND
8-bit NAND device
Block invalid when any byte
6th byte in 1st page
1st byte in 1st page
does not equal FFh
6th byte in 2nd page
1st byte in 2nd page
16-bit NAND device
Block invalid when any word
1st word in 1st page
1st word in 1st page
does not equal FFFFh
6th word in 1st page
1st word in 2nd page
1st word in 2nd page
6th word in 2nd page
shows the invalid block detection routine. The routine consists in reading spare areas and
checking data according to the conditions listed in Table 26-35. The flags are used internally to give
information about the validity of each block.
Figure 26-18. Bad NAND Invalid Block Detection
26.4.7.4.2 SLC NAND Read Sector Procedure
During the booting procedure, the ROM code reads 512-byte sectors from the NAND device. The reading
fails in two cases:
•
The accessed sector is in a block marked as invalid.
•
The accessed sector contains an error that cannot be corrected with ECC.
3552
Initialization
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated