5 nandflash boot – Rainbow Electronics AT91CAP9S250A User Manual
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6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
Figure 14-6. Serial DataFlash Download
14.5
NANDFlash Boot
The NANDFlash Boot program searches for a valid application in the NANDFlash memory.
First, it looks for a boot.bin file in the root directory or in the FIRMWARE directory of a
FAT12/16 formatted NANDFlash. If a valid file is found, this application is loaded into internal
SRAM and executed by branching at address 0x0000_0000 after remap. This application may
be the application code or a second-level bootloader.
If NANDFlash is not formatted, the NANDFlash Boot program searches for a valid application
in the NANDFlash memory. If a valid application is found, this application is loaded into internal
SRAM and executed by branching at address 0x0000_0000 after remap. See
for more information on Valid Image Detection.
End
Read the first 7 instructions (28 bytes).
Decode the sixth ARM vector
Yes
Read the DataFlash into the internal SRAM.
(code size to read in vector 6)
Restore the reset value for the peripherals.
Set the PC to 0 and perform the REMAP
to jump to the downloaded application
Send status command
7 vectors
(except vector 6) are LDR
or Branch instruction
Yes
Start
Is status OK ?
Jump to next boot
solution
No
No