IMX8MPlus Disabling M7 core

AlfTeleco — Wed, 24 Nov 2021 10:45:00 GMT

Hi all,

In order to keep power consumption as low as possible we are implementing everything we can.

Between all the things we've tried we want to disable the cortex M7 as we don't use it.

To get this I tried to burn the fuse M7_DISABLE, which according to Security Reference Manual for i.MX 8M Plus Applications Processor, Rev. 0, 04/2021 page 177, is the 21 bit of the 0x440 fuse register address.

I look for this address and the same reference manual told me that it is the HW_OCOTP_TESTER3 register, which is the OTP Bank1 and word 0.

The problem is that when I want to burn it using the uboot command "fuse prog" I get this error:

Why is this so? Why can I not burn the fuse?

I am also wondering if there could be some mistakes or errata, as I have found some. For instance the address of the SEC_CONFIG[0] fuse is given twice and differently.

Security Reference Manual for i.MX 8M Plus Applications Processor, Rev. 0, 04/2021 page 176:

SEC_CONFIG[0] address is 0x440[17]

and in page 104:

SEC_CONFIG[0] address is 0x450[17].

Which one is the correct? Apart from this, the main question is, is it possible to disable the CoreM7? and if so, how?

Thanks in advance

Re: IMX8MPlus Disabling M7 core

igorpadykov — Wed, 24 Nov 2021 23:59:38 GMT

Hi Alvaro

I am afraid it is not possible to disable the CoreM7, that fuse can be changed on factory.

Correct is SEC_CONFIG[0] address is 0x440[17].

Best regards
igor

i.MX ProcessorsのトピックIMX8MPlus Disabling M7 core

IMX8MPlus Disabling M7 core

Re: IMX8MPlus Disabling M7 core