Atmel SAM9X25, Manual

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SAM9X25
11.4.2 NVM Bootloader Program Description
Figure 11-3. NVM Bootloader Program Diagram
The NVM bootloader program first initializes the PIOs related to the NVM device. Then it config-
ures the right peripheral depending on the NVM and tries to access this memory. If the
initialization fails, it restores the reset values for the PIO and the peripheral and then tries the
same operations on the next NVM of the sequence.
If the initialization is successful, the NVM bootloader program reads the beginning of the NVM
and determines if the NVM contains valid code.
If the NVM does not contain valid code, the NVM bootloader program restores the reset value for
the peripherals and then tries the same operations on the next NVM of the sequence.
End
Valid code detection in NVM
Yes
Copy the valid code
from external NVM to internal SRAM.
Restore the reset values for the peripherals.
Perform the REMAP and set the PC to 0
to jump to the downloaded application
Initialize NVM
NVM contains valid code
Yes
Start
Initialization OK ?
Restore the reset values
for the peripherals and
Jump to next boot solution
No
No