Datasheet

 2017 Microchip Technology Inc. DS60001516A-page 71
SAM9G20
Note: Booting either on USB or on DBGU is possible with any of these input frequencies.
5. Initialization of the DBGU serial port (115200 bauds, 8, N, 1)
6. Jump to Serial Flash Boot sequence through NPCS0. If Serial Flash Boot succeeds, perform a remap and jump to 0x0.
7. Jump to DataFlash Boot sequence through NPCS0. If DataFlash Boot succeeds, perform a remap and jump to 0x0.
8. Jump to Serial Flash Boot sequence through NPCS1. If Serial Flash Boot succeeds, perform a remap and jump to 0x0.
9. Jump to DataFlash Boot sequence through NPCS1. If DataFlash Boot succeeds, perform a remap and jump to 0x0.
10. Jump to NAND Flash Boot sequence. If NAND Flash Boot succeeds, perform a remap and jump to 0x0.
11. Jump to SDCard Boot sequence. If SDCard Boot succeeds, perform a remap and jump to 0x0.
12. Jump to EEPROM Boot sequence. If EEPROM Boot succeeds, perform a remap and jump to 0x0.
13. Activation of the Instruction Cache
14. Jump to SAM-BA Boot sequence
15. Disable the WatchDog
16. Initialization of the USB Device Port
Figure 12-2: Remap Action after Download Completion
12.4 Valid Image Detection
The DataFlash Boot software looks for a valid application by analyzing the first 28 bytes corresponding 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/her own vector (see
“Structure of Arm Vector 6”).
12.4.1 Valid Arm exception vectors
Figure 12-3: LDR Opcode
11.05920 12.0 12.288 13.56 14.31818
14.7456 16.0 17.734470 18.432 20.0
24.0 24.576 25.0 28.224 32.0
33.040.048.050
Table 12-4: Input Frequencies Supported (OSCEL = 1)
REMAP
Internal
ROM
Internal
SRAM
Internal
SRAM
Internal
ROM
0x0020_0000
0x0000_0000
0x0010_0000
0x0000_0000
31 28 27 24 23 20 19 16 15 12 11 0
111001IPU0W1 Rn Rd