i.MX ProcessorsのトピックRe: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

TBYE — Wed, 21 Jul 2021 05:20:56 GMT

Hi, How can i fuse SJC_DISABLE or enable Secure JTAG on imx8mm

Where can i find the fuse bit, word and bank

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

igorpadykov — Wed, 21 Jul 2021 11:11:19 GMT

Hi Erza

fuses can be programmed using uboot, fuses description were sent via mail.

https://community.nxp.com/t5/i-MX-Processors/FUSE-programming-in-imx8-M-mini/m-p/982011

Best regards
igor

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

TBYE — Wed, 21 Jul 2021 12:07:31 GMT

How can we calculate fuse bank and word for the same?

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

Silvarye — Wed, 21 Jul 2021 12:21:14 GMT

Hi,

yes, so with uboot you can program SJC_DISABLE like this :

=> fuse prog 1 3 0x200000

And for enable Secure JTAG check the fuse Map in the reference manual at the address 0x470[23:22]

So, for find the fuse bit, word and bank,

1st, you need to find in the fuse map what you search, after you have the address (for example 0x470[23;22])

2nd, with the address you can find in the OCOTP memory map which word and bank correspond for your address (for example 470 correspond to Value of OTP Bank1 Word3)

3rd, use Uboot : => fuse prog <bank> <word> <bit address>

For example, for SJC_DISABLE it's 0x470[21]

so 470 --> bank 1 word 3

bit 21 -> 1 : 0x200000 (1000000000000000000000)

so you have your command : => fuse prog 1 3 0x200000

Hope I was clear

Best regards,

Alexandre.

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

TBYE — Wed, 21 Jul 2021 12:32:01 GMT

@Silvarye is this address 0x470[23:22] for imx8m mini?

IF yes please share the reference.

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

Silvarye — Wed, 21 Jul 2021 13:05:28 GMT

I work on the imx8m Nano, but you can do a request for your board : Security Reference Manual for i.MX 8M Mini Applications Processor (nxp.com)

For answer to your question I think it's the same fuse so, yes 0x470[23:22] (JTAG_SMODE) it's for imx8m mini too.

But before burning fuse, when you will have this document check in the Fuse Map for your board, it's more safe.

Best regards,

Alexandre.

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

igorpadykov — Wed, 21 Jul 2021 14:33:43 GMT

it is the same as below, only Bank: Group of 4 words: https://imxdev.gitlab.io/tutorial/Burning_eFuses_on_i.MX/

example https://developer.solid-run.com/knowledge-base/efuses-for-i-mx8m-mini-som/

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

TBYE — Thu, 22 Jul 2021 05:41:22 GMT

Hi @igorpadykov

fuses description you have sent via mail, are these applicable for IMX8M Mini.

Because i could not find the same in imx8mmrm or imx8mmsrm.

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

igorpadykov — Thu, 22 Jul 2021 05:50:01 GMT

yes they are for i.MX8M Mini.

Re: Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

antho — Tue, 21 Mar 2023 11:44:51 GMT

Hi,

What's register 0x470[23:22] (JTAG_SMODE) value to configure JTAG in mode #1 please ?

I asked NXP for security documentation but have no response yet...

Thanks !