topic Re: i.MX8M nano Fusemap Bit Array in i.MX Processors

i.MX8M nano Fusemap Bit Array

danab — Wed, 15 Oct 2025 15:42:28 GMT

I am having a difficult time figuring out which fuses on the i.MX8M nano are in the fuse array and which are bank/word. Which fuses can be burned a fuse at a time, and which must be burned a word at at time?

Thanks!

Re: i.MX8M nano Fusemap Bit Array

JosephAtNXP — Wed, 15 Oct 2025 16:34:14 GMT

Hi,

Thank you for your interest in NXP Semiconductor products,

You can burn fuses by word, you first need to identify what word you want to burn, e.g. 480 fuse, which is bank 2 word 0.

Then, confirm the lock bits in the words if the word has lock bits that you want to SET, I would recommend burning lock bits first and then burn the rest of the fuses.

In summary, all can be word size burned, but I recommend burning first lock bits by word then the rest of the bits of that word.

Regards

Re: i.MX8M nano Fusemap Bit Array

danab — Wed, 15 Oct 2025 17:24:59 GMT

Thank you for your reply, Joseph. Let me see if I understand this correctly.

Let's say, for instance, I burn 0x450 bit 8 with 0x00000100, could I then go back and burn 0x450 bit 24 with 0x01000000? Assuming after both writes the fuses would be 0x01000100. Or can I only write to that address 1 time?

Also, if I burn the lock fuses first, wouldn't that prevent me from burning the fuses they are controlling?

Kind Regards

Re: i.MX8M nano Fusemap Bit Array

JosephAtNXP — Wed, 15 Oct 2025 20:32:22 GMT

Hi @danab,

Yes, that is also valid, I said the most quick way to write the fuses, the other end option is the one that you said, you burn/set a fuse bit and later burn another one from the same word, in the next operation you can write 0 to previous burned fuses and have no effect, as described by you.

Yes, setting lock bits prevent from writing to the protected bits.

Let me know if you have further questions.

Regards!

Re: i.MX8M nano Fusemap Bit Array

danab — Thu, 16 Oct 2025 11:04:36 GMT

Thanks, Joseph!