SMARC-sAMX8X User Guide. Rev. 1.1
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6/
Installation
6.1.
Boot Process
On power-on, the module searches u-boot image on following storage devices in this order:
1.
Module QSPI NOR flash
2.
Carrier SD card
If no valid u-boot image is found, the boot process then jumps into Serial Download Mode where it waits for mfgtool
commands over USB2 OTG. When FORCE_RECOV# is pulled down, the boot process jumps directly into Serial
Download Mode without looking for a valid boot image.
Carrier BOOT_SEL pins (BOOT_SEL0#, BOOT_SEL1# and BOOT_SEL2#) are available as GPIO inputs in u-boot. These
inputs can be used to customize boot process via u-boot macros.
6.2.
PCIe Switch options
There are four different configurations available to configure the PCI switch:
Configuration 1 (default)
Second Ethernet on ETH1
1 x PCIe to LAN Controller via PCIe SW
2x PCIe at SMARC connector via PCIe SW (PCIeA + PCIeB)
PCIe Switch and LAN Controller
Configuration 2
No ETH1
1x PCIe A on SMARC connector directly from i.MX8 CPU
Without PCIe Switch and LAN Controller
Configuration 3
LAN Controller directly connected to PCIe from CPU
No PCIe on SMARC connector
Without PCIe Switch
Configuration 4
No ETH1
3x PCIe at SMARC connector via PCIe SW (PCIe A, PCIe B, PCIe C)
PCIe Switch without LAN Controller
