Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

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Programming SJC_DISABLE, JTAG_SMODE fuses on iMX8MM

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TBYE
Contributor I

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

Where can i find the fuse bit, word and bank

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Silvarye
Contributor II

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.

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TBYE
Contributor I

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

IF yes please share the reference.

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Silvarye
Contributor II

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.

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igorpadykov
NXP TechSupport
NXP TechSupport

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

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TBYE
Contributor I

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.

 

 

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igorpadykov
NXP TechSupport
NXP TechSupport

yes they are for i.MX8M Mini.

 

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TBYE
Contributor I

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

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igorpadykov
NXP TechSupport
NXP TechSupport
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