User manual
Design Considerations
29
Boot Value SPI0
NPCS0
SD Card
MCI0
SD Card
MCI1
NAND
Flash
SPI0
NPCS1
TWI
EEPROM
SAM-BA
0 Yes Yes Yes Yes Yes Yes Yes
1 Yes No Yes Yes Yes Yes Yes
2 Yes No No Yes Yes Yes Yes
3 Yes No No No Yes Yes Yes
4 Yes No No No Yes Yes Yes
5-7 No No No No No No Yes
Table6.1.SAMA5D3X Boot Sequence
Please note, that boot from SD Card (MCI1) is not working according to the errata of the
Microcontroller.
6.4.2. SAM-BA Monitor
If no valid code is found along the configured sequence the SAM-BA monitor is launched.
The SAM-BA Monitor initializes the DBGU and USB-Device. It then checks if an USB device
enumeration occurs or if characters are received on the DBGU. Once the communication
interface is identified, it runs an infinite loop, waiting for commands.
The SAM-BA monitor allows programming of flash or similar. For this purpose Atmel
provides a tool running on desktop PCs. If you need to use the SAM-BA monitor and have
valid code on one of the booting devices, these have to be disabled first (e.g. disable
chipselect of serial or nand flash or remove SD/MMC-Card).
6.4.3. Design Constraints
The boot sequence affects the design of the pins, which are initialized during the boot
sequence. When using pins in a different multiplexing, which are also assigned to a boot
device, it has to be kept in mind that these pins could be muxed for the relevant peripheral
during boot process and accordingly driven by the microprocessor. Programming the boot
sequence controller may help to avoid unwanted side effects.
Before performing the jump to the application in the internal SRAM, all PIOs and
peripherals used in the boot program are set to their reset state
Boot Device Pin Pio Line Pin on Stamp
CK PD9 Bus 71
CDA PD0 Bus 76
DA0 PD1 Bus 75
DA1 PD2 Bus 74
DA2 PD3 Bus 73
SD Card MCI0
DA3 PD4 Bus 72
MOSI PD11 IO 94
MISO PD10 IO 95
SPCK PD12 IO 93
SPI Flash SPI0
NPCS0 PD13 IO 92