How do I disable JTAG on i.MX21 for security reasons?

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How do I disable JTAG on i.MX21 for security reasons?

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ChrisDarrow
Contributor III

I received a question from a customer about turning off JTAG on the MC9328MX1 processor for security reasons. They do not want anyone "back dooring" into their system. I know the newer processors give you the ability to disable JTAG, for this very reason. But I did not see anything for the MC9328MX1. Do you know if there is any method to disable the JTAG port? If not, is there another way (HW or SW) that you are aware of that would provide this functionality?

My customer already has their system in production, and therefore, they cannot consider a newer processor for the current platform. They need to solve this problem on their i.MX21 based platform.

Thanks.

2 Replies

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art
NXP TechSupport
NXP TechSupport

Unfortunately, there is no way to physically disable the JTAG controller, e.g. by blowing some OTP bit, in the i.MX21 processor. Also, there seems to be no reliable way to secure the JTAG controller in software. The only way to avoid unwanted access to the JTAG port seems to make the port physically inaccessible, e.g. by not routing the JTAG signals out of the processor's PCB footprint and hardwiring all of them (except for TDO) to NVDD power rail within the PCB.


Have a great day,
Artur

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274 Views
ChrisDarrow
Contributor III

Sorry for the confusion. The part number in question is MC9328MX21VM

Thanks,

Chris

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