i.MX8M Mini Boot Mode with eFuse

[lumen]

Hi all,

My question is regarding the boot mode selection of the i.MX8M Mini.

We would like to use the BOOT_MODE pins to boot from different boot devices (eMMC, SD, Serial Downloader). If the eFuse GPIO_BT_SEL = 0 is set is the following statement correct?

BOOT_MODE = 00 -> Boot From Fuses (eFuses configured for SD)

BOOT_MODE = 01 -> Serial Downloader

BOOT_MODE = 10 -> Boot From eMMC (Configuration set by GPIOs)

Best Regards,

Patrick

[joanxie]

you can refer to the Table 6-14. USDHC boot eFUSE descriptions of Reference Manual,

BOOT_CFG[6:4]=001, BOOT_CFG[15:12]=0010

[joanxie]

BOOT_CFG[6:4]=001, BOOT_CFG[15:12]=0010

[lumen]

Hi joanxie,

Thanks for your reply. The boot configuration for the different boot devices is clear to me.

Is it possible to change the different boot devices with BOOT_MODE GPIOS if GPIO_BT_SEL = 0?

Best Regards,

Patrick

[joanxie · Accepted solution]

refer to the chapter 6.1.2.3 Boot From Fuses mode (BOOT_MODE[1:0] = 00b):

In this mode, the GPIO boot override
pins are ignored. The boot ROM code uses the boot eFUSE settings only.

refer to the chapter 6.1.2.5 Internal Boot mode (BOOT_MODE[1:0] = 0b10):

The GPIO Boot Select FUSE (BT_FUSE_SEL) determines whether the
ROM uses the GPIO pins for a selected number of configuration parameters or eFUSEs
in this mode.
• If BT_FUSE_SEL = 1, all boot options are controlled by the eFUSEs described in
Table 6-2.
• If BT_FUSE_SEL = 0, the specific boot configuration parameters may be set using
the GPIO pins rather than eFUSEs. The fuses that can be overridden when in this
mode are indicated in the GPIO column of Table 6-2. Table 6-3 provides the details
of the GPIO pins.

so if you want to use gpio override mode, you need to set BOOT_MODE[1:0] = 10  and BT_FUSE_SEL = 0