AT91SAM9G10-EK Atmel, AT91SAM9G10-EK Datasheet - Page 76

• Manufacturer Part Number: AT91SAM9G10-EK
• Description: KIT DEV FOR SAM9G10 ARM
• Manufacturer: Atmel
• Type: MCUr

Specifications of AT91SAM9G10-EK

• Contents: Board, Cables, Power Supply
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Kit Contents: Board
• Svhc: No SVHC (15-Dec-2010)
• Mcu Supported Families: AT91SAM9G10, ARM926EJ-S
• Tool / Board Applications: Microcontroller
• Rohs Compliant: Yes
• For Use With/related Products: *
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

13.4
13.4.1
13.4.2
76
Valid Image Detection
AT91SAM9G10
Valid ARM Exception Vectors
Structure of ARM Vector 6
Figure 13-2. Remap Action after Download Completion
The DataFlash Boot software looks for a valid application by analyzing the first 28 bytes corre-
sponding to the ARM exception vectors. These bytes must implement ARM instructions for
either branch or load PC with PC relative addressing.
The sixth vector, at offset 0x14, contains the size of the image to download. The user must
replace this vector with his own vector (see
Figure 13-3. LDR Opcode
Figure 13-4. B Opcode
Unconditional instruction: 0xE for bits 31 to 28
Load PC with PC relative addressing instruction:
The ARM exception vector 6 is used to store information needed by the DataFlash boot pro-
gram. This information is described below.
31
31
1
1
1
1
– Rn = Rd = PC = 0xF
– I==0
– P==1
– U offset added (U==1) or subtracted (U==0)
– W==1
1
1
28 27
28 27
0
0
0x0000_0000
0x0030_0000
0
1
1
0
1
I
24 23
24 23
P
0
U
Internal
Internal
SRAM
ROM
0
W 1
20 19
“Structure of ARM Vector 6” on page
Rn
REMAP
16 15
Offset (24 bits)
Rd
Internal
Internal
SRAM
ROM
12 11
0x0000_0000
0x0010_0000
6462A–ATARM–03-Jun-09
76).
0
0