topic Re: S32K14x JTAG lock in S32K

S32K14x JTAG lock

zhou_gaga — Fri, 10 Feb 2023 07:10:31 GMT

I use backdoor_key_verify to implement JTAG unlock, and CAN send FTFC-&gt before and after using backdoor_key_verify; The FSEC state, we see from the beginning FSEC[SEC]=11b changes to FSEC[SEC]=10b, so the jtag unlocked, but I still won't get through the J-FLASH burning program.

Re: S32K14x JTAG lock

danielmartynek — Fri, 10 Feb 2023 11:40:46 GMT

Hello @zhou_gaga,

The MCU stays unloked as long as the MCU is not reset.

After any reset, the MCU is locked again.

So, the programmer must not reset the MCU.

Please contact SEGGER support if you want to reprogram the MCU using J-Flash.

Thank you,

BR, Daniel

Re: S32K14x JTAG lock

zhou_gaga — Fri, 10 Feb 2023 12:56:25 GMT

Do you mean that j-flash burning program will cause a reset? In addition, j-flash read back to flash is also failed. So I wanted to know exactly what the unlocked swd mode feature would do.

Re: S32K14x JTAG lock

danielmartynek — Fri, 10 Feb 2023 14:21:56 GMT

For example, the PEMicro plugin in the S32DS IDE has this feature that allow connecting the programmer without reset.

This way, we can attach the debugger while the MCU is unlocked and running.

For more information about the J-Flash flashing algorithm, please contact SEGGER.

Thank you,

BR, Daniel

Re: S32K14x JTAG lock

zhou_gaga — Fri, 10 Feb 2023 15:26:36 GMT

Besides, can I burn a new program after jtag unlocked? If so, how to operate it?

Re: S32K14x JTAG lock

zhou_gaga — Mon, 13 Feb 2023 02:24:53 GMT

I tried the method you said, but the PE displayed "Warning: Unable to go to background. Core is running", but the CAN message showed FSEC[SEC]=10b (unsecured).

Re: S32K14x JTAG lock

danielmartynek — Tue, 14 Feb 2023 09:10:09 GMT

Hello @zhou_gaga,

You are supposed to get a warning, the core is running.

The debugger is attached to a running target.

Can you halt the execution?

Regards,

Daniel

Re: S32K14x JTAG lock

zhou_gaga — Wed, 15 Feb 2023 07:07:47 GMT

Suddenly it can read. But I still have a question, if PE is configured as "Attach to Running Target", then will MCU load the previous program or the program of the current project? Also, if I unlock through backdoors, how do I burn new programs?

Re: S32K14x JTAG lock

danielmartynek — Wed, 15 Feb 2023 11:51:13 GMT

Hello @zhou_gaga,

In the attach debug session, the MCU is not being programmed, it is just attached to the MCU while the MCU is running the previously loaded project.

I would recommend contacting PEMicro support and ask for an algorithm the does not reset the MCU before the flashing.

You could also you J-link commander:

Once the MCU is unlocked, a special J-Link script is necessary, which can be found here: https://wiki.segger.com/S32Kxxx#Attach_to_debug_session

J-Link commander need to be called in the following way:

C:\Programm\SEGGER\JLink\JLink.exe -JLinkScriptFile NXP_Kinetis_S32_Attach.JLinkScript

Then, the MCU is not reseted and access to all memory and registers is possible.

You can try to load the project via the commander.

Or please contact SEGGER support.

Regards,

Daniel