Datasheet

SAM9263 [DATASHEET]
Atmel-6249N-ATARM-SAM9263-Datasheet_14-Mar-16
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12. SAM9263 Boot Program
12.1 Overview
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 SD Card Boot program is executed. It looks for a boot.bin file in the root directory of a FAT12/16/32
formatted SD Card. If such a file 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 the SD Card is not formatted or if boot.bin file is not found, NAND Flash Boot program is then executed.
The NAND Flash Boot program looks for a sequence of seven 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, the DataFlash Boot program is executed. It looks for a sequence of
seven 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 boot.bin file is found, SAM-BA Boot is then executed. It waits for transactions either on the USB device, or on
the DBGU serial port.