at91sam9260-cj ATMEL Corporation, at91sam9260-cj Datasheet - Page 75

• Manufacturer Part Number: at91sam9260-cj
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

13. AT91SAM9260 Boot Program
13.1
13.2
6221G–ATARM–31-Jan-08
Description
Flow Diagram
The Boot Program integrates different programs permitting download and/or upload into the dif-
ferent 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 excep-
tion 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 sec-
ond 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
tions either on the USB device, or on the DBGU serial port.
The Boot Program implements the algorithm in
Figure
®
Boot is then executed. It waits for transac-
13-1.
AT91SAM9260
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