Regarding Boot Configuration Settings on MIMXRT1170

[SK_20]

Dear NXP Support Team,

I have a couple of questions regarding the boot configuration settings for our project:

1. Can we use BOOT_CFG[0:11] as individual functions when booting from fuses?
2. When using the "Boot from Fuses" settings, do the BOOT_CFG[0:11] pins need to be pulled down or set to any specific state?

I have attached images for your reference. Please update me as soon as possible.

Your assistance in clarifying these points would be greatly appreciated.

I appreciate your support.

Best regards,

Sagar

[Omar_Anguiano · Accepted solution]

If using boot from fuses then the boot_cfg pins can be used for other purpose as the ROM will read the values from the fuses instead of the GPIOs.

The state of the pins can be as a normal pin as the state of the GPIO will not be read on that mode.

Best regards,
Omar

[SK_20]

Hello @Omar_Anguiano ,

Thank you for the quick reply.

I have another query: if we use Boot from Fuses, can we change it later if we want to?

Is Serial Downloader and Internal Boot compulsory? If we set the fuses, can we change the fuse settings afterward?

In the reference design file, it is mentioned that the Boot Mode selection header should be used only during the development phase. We use Boot Selection settings during the development phase, but after finalizing the production phase, we switch to Boot from Fuses. What happens if we want to change the bootloader and firmware again after setting Boot from Fuses?

Thanks 
Sagar

[Omar_Anguiano]

Fuses cannot be re-written. It is suggested to use the fuse configuration once you are completely sure that the parameters are correct. 
Even with the fuse configuration you are able to enter serial download mode if boot_mode pin is available. 

The ROM will behave like this:
Boot_Mode is configured in Boot From Fuses (b00)
- BT_FUSE_SEL = 0, No application in boot device, BootROM enters serial downloader mode
- BT_FUSE_SEL = 1, valid application in boot device, BootROM gets all boot device info from fuse

Boot_Mode is configured in Internal Boot (b10)
- BT_FUSE_SEL = 0, valid application in boot device, BootROM gets boot device info from boot_cfg pins.
- BT_FUSE_SEL = 1, valid application in boot device, BootROM gets all boot device info from fuse

Best regards,
Omar