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11. SAM9260 Boot Program
11.1 Description
The Boot Program integrates different programs permitting download and/or upload into the different memories of
the product.
First, it initializes the Debug Unit serial port (DBGU) and the USB Device Port.
Then the DataFlash Boot program is executed. It looks for a sequence of eight valid ARM exception vectors in a
DataFlash connected to the SPI. All these vectors must be B-branch or LDR load register instructions except for
the sixth vector. This vector is used to store the size of the image to download.
If a valid sequence is found, code is downloaded into the internal SRAM. This is followed by a remap and a jump to
the first address of the SRAM.
If no valid ARM vector sequence is found, the DataFlash Boot program is executed on the second chip select.
If no valid ARM vector sequence is found, NAND Flash Boot program is then executed.
The NAND Flash Boot program looks for a sequence of eight valid ARM exception vectors. If such a sequence is
found, code is downloaded into the internal SRAM. This is followed by a remap and a jump to the first address of
the SRAM.
If no valid ARM vector sequence is found, SAM-BA Monitor is then executed. It waits for transactions either on the
USB device, or on the DBGU serial port.
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; Standard definitions of Mode bits and Interrupt (I & F) flags in PSRs
ARM_MODE_USR EQU 0x10
ARM_MODE_FIQ EQU 0x11
ARM_MODE_IRQ EQU 0x12
ARM_MODE_SVC EQU 0x13
ARM_MODE_ABT EQU 0x17
ARM_MODE_UND EQU 0x1B
ARM_MODE_SYS EQU 0x1F
I_BIT EQU 0x80 ; when I bit is set, IRQ is disabled
F_BIT EQU 0x40 ; when F bit is set, FIQ is disabled
AT91C_BASE_AIC EQU 0xFFFFF000
AIC_IVR EQU 0x100
AIC_EOICR EQU 0x130
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