TCC720 Datasheet, PDF (136/143 Pages) List of Unclassifed Manufacturers – 32-bit RISC Microprocessor For Digital Media Player

TCC720
32-bit RISC Microprocessor for Digital Media Player
Dec. 16. 2002
BOOTING PROCEDURE
Preliminary Spec 0.51
before returning from the initialization code.
The initialization code must be encapsulated by the entrance command of ‘STR LR, [SP - #4]!’,
and the exit command of ‘LDR PC, [SP], #4’. This code may contain various routines such as
memory configuration or user customized booting code itself.
After the initialization code finishes, and the code returns by the above exit code, the main F/W
copy code begins copy from the start page contained in R0 register. TCC720 copies the size of
page – 8 bytes of codes per every page to the area starting from the address of ‘0x00000000’.
You must configure this area appropriately before returning from the initialization code. In case
of encrypted F/W code, it is decrypted and then copied to as like as in non-encrypted case.
The next page number is consisted of 4 bytes and located at (the size of page – 7) ~ (the size of
page – 4) in current page of data to be copied. The last 4 bytes in page of data are reserved for
future use.
If the next page number is equal to ‘0xFFFFFFFF’, that page is the last page containing F/W
code. TCC720 copy F/W code until this number is acquired.
Figure 14.3 illustrates the organization of NAND flash.
1 Page
Initialization Code (Page size - 4 bytes)
Spare area
S₀ C4
Last Page
of NAND
Start flag
Start page number (= S₀)
S₀
1st Code of F/W (Page size - 8 bytes)
S₁
next page number (= S₁)
S₁
2nd Code of F/W (Page size - 8 bytes)
S₂
next page number (= S₂)
S_n Last Code of F/W (Page size - 8 bytes)
-1
Last page flag (= 0xFFFFFFFF)
1st Page
of NAND
Figure 14.3 The boot code structure in NAND flash
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