JTAG Secure Mode

[CPete12]

Dear all,

As I understand I can lock the JTAG port during programming, which is highly applreciated. However, in the Manual, it says that it is also possible to later unlock the port again, which is undesirable. Is there a way to permanently lock the JTAG port and if so how?

Any suggestions are highly appreciated.

many thanks!

[YuanLi_S_Intel]

Hi Christian Peters, Yes, you can enabled the JTAG Secure Mode by burning the fuse of tamper-protection bit. This will cause the FPGA in JTAG Secure Mode permanently. https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/an/an556.pdf (Page 5) Regards, YL

[CPete12]

Dear YL,

Thankyou for your reply! I forgot to mention that I am looking at a MAX10, which runs on TSMC's 55nm process, so the above feature does not apply (I am sorry for wasting your time and not mentioning it before). I know I can lock the JTAG duing programming, but there seems to be a way to unlock it by instatinating the internal JTAG and pulling the start_unlock port (see

<a href="https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/max-10/ug_m10_config.pdf">MAX 10 Configuration File</a>

section 3.9.4). How can I turn this feature off? Or is it tunred off by default? Is there any literature that you could suggest?

Many thanks again,

Chistian

[YuanLi_S_Intel]

Hi Christian, The JTAG Secure Mode is unlock by default. Once you LOCK the JTAG Secure Mode, the device is in JTAG Secure mode after power-up and configuration. If you are speaking about the feature to turn on (LOCK) and off (UNLOCK) the JTAG Secure Mode, what you need to do is burn the fuse of tamper-protection bit. This will permanently cause the FPGA in JTAG Secure Mode. If it is permanently in JTAG Secure Mode, that means, you cannot unlock the JTAG Secure Mode. Regards, Yuan Li