Toshiba TLCS-900/H1 Series Manual page 449

(4) Error check item
The items checked by the boot program are given below.
If an error occurs in any check, the boot program will cancel downloading from
NAND flash and skip to the next operation (recognizing UART or USB).
a) Supported NAND flash
The boot program reads a device code from NAND flash and checks whether it is
supported or not.
b) Boot identification code
c) User program size
The boot program checks whether it is less than or equal to 10 Kbytes.
d) Block status area
The boot program checks whether each block is normal or not. If the block
status area on first page of any block has 2-bit or more "0" data, it is an error.
e) Data status area
The boot program checks whether each data status is correct or not. If the data
status area has 4-bit or more "0" data, it is an error.
f) ECC error
The boot program reads both calculated code from NDFC and ECC code in
NAND flash and checks whether they are correctable or not.
g) NAND flash R/B
The boot program checks whether NDR/B pin is normal or not in each action.
If the busy status is longer than 70 [μs] at f
(5) ECC error check
a) Calculation ECC code
The NDFC (NAND flash controller) is used for calculation of ECC code.
b) ECC code correction
The boot program operates as below.
1. Compares both calculated ECC code from NDFC and ECC code in NAND
flash.
2. Evaluates and corrects according to the following cases.
Case (a): No data error
Case (b): 1-bit data error
Case (c): 2-bit or more data error
Case (d): ECC code 1-bit error
Case (e): ECC code 2-bit or more error → (Error) Termination
92CH21-447
TMP92CH21
= 40 MHz, it is an error
FPH
→ (OK) Next operation
→ (OK) Error correction
and next operation
→ (Error) Termination
→ (OK) Next operation
.
2009-06-19