i.MX8M Nano eMMC boot options

[JHT]

Hello,  We have developed a custom i.MX8M Nano application bd.  We are currently booting from NOR but would like to have the option to boot from eMMC as well.  Looking through the flash controller documentation it seems feasible to wire this to the SD1 interface. The question we have is regarding boot.  The default from Boot_Mode[1] is from USHDC3 (the SD3) interface.  However according to the RM we can boot from any SD port using fuses.

If we wanted to boot from USDHC1 we need to write 01(b) to bits 10:9 of fuses at 0x470.  Is our understanding that doing this would allow us to boot from eMMC on SD1?  Specifically if we set fuses as per above and used resistor select 0010 basically setting Boot_Mode_[1].   The fuse selection in this case would allow the i.MX8MN to overide USDHC3. 

If we have misunderstood or this is not possible, any clarification would be greatly appreciated.

[JosephAtNXP]

Hi,

Thank you for your interest in NXP Semiconductor products.

Your understanding is correct, you can refer to 6.1.5.4.1 Expansion device eFUSE configuration.

• 11 - 9: Select which SDHC module and what flash you will use but you need to override.
• 15 - 12: You also need to tell the fuses to boot from emmc.
• And you need to tell the device to boot from fuses either from pins to 0000 or the override pins fuse.

Regards