How to disable JTAG on i.MX 8M?

christian_mauderer · ‎09-09-2019

The i.MX 8M reference manual mentions a JTAG_SMODE[1:0] and a SJC DISABLE e-fuse that are necessary to disable JTAG access. But I can't find the address or location of the fuses. Where can I find them? Is there some document describing it?

bernhardfink · ‎10-06-2022

Here is the description of these fuse bits:

Fuse Address	Fuse Name	Function	Setting
0x470[21]	SJC_DISABLE	Disable/Enable the Secure JTAG Controller module. This fuse is used to create highest JTAG security level, where JTAG is totally blocked.	0 - Secure JTAG Controller is enabled 1 - Secure JTAG Controller is disabled
0x470[23:22]	JTAG_SMODE[1:0]	JTAG Security Mode. Controls the security mode of the JTAG debug interface	00 - JTAG enable mode 01 - Secure JTAG mode 1x - No debug mode

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marcelziswiler · ‎11-16-2019

Thanks, igorpadykov, very helpful to answer this by mail!

How about others like us who are also wondering about all this?

christian_mauderer · ‎09-10-2019

Hello Igor,

thank you. That solved my question.

Best regards

Christian

How to disable JTAG on i.MX 8M?

How to disable JTAG on i.MX 8M?

i.MX 8M | i.MX 8M Mini | i.MX 8M Nano