Hoe to disable JTAG in i.MX6UL? And how to verify, it is disabled?

[kavita]

Hi there,

In Imx6UL, to disable JTAG, which command I have to use?

Also, as per Application Note AN12419, SJC_DISABLE need to be blown with 1 and JTAG_SMODE[1:0] need to be 11.

Can you particularly guide for command to blow above bits?

Is the SJEC_RESP can be alternate method to above method?

Thank you in advance!

Kavita

[Chavira]

Thank you for contacting NXP support!

You have to program the SJC_DISABLE and JTAG_SMODE.

JTAG_SMODE : JTAG Security Mode. Controls the security mode of the JTAG debug interface

Set JTAG security mode
00 - JTAG enable mode
01 - Secure JTAG mode
11 - No debug mode

SJC_DISABLE: Disable/Enable the Secure JTAG Controller module. This fuse is used to create the highest JTAG security level, where JTAG is totally blocked.

0 - Secure JTAG Controller is enabled
1 - Secure JTAG Controller is disabled

you can learn how to program and read the fuses following the link:

Q&A: How to program i.MX6 eFUSE? - NXP Community