KL16 and KL26 going to secure mode

[yasararafathcs]

Hi All,

We are using KL series processor for thermal printer application. After working a couple of days at the time of debugging with Codewarrior, process is stopping in 71% and processor is falling to Secure mode. I referred the old discussions in the community and not able to get back the processor from secure mode. Can anyone suggest what will be the reason for this?

Thanks & Regards,

Yasar Arafath

[kerryzhou]

Hi Yasar Arafath,

    There has  a document about Kinetis Lock issue analysis and unlock way, please refer to it and check your hardware:

   Kinetis Lock issue analysis and unlock way.pdf

Wish it helps you!

Have a great day,
Kerry

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[yasararafathcs]

Hi Zhou,

Thank you for the information and the sharing the document. I tried with the procedure from the section 3. Unlock way (from easy to complex) with JFlash Tool and JLink Commander. In both method it is showing error like Device is Secure, it will perform mass erase. But after some seconds it is showing unable to connect the device and timedout. After grounding RESET pin of the debugger also I tried couple of times. It also not worked out.

For the above method instead of JLink debugger I used K40 KwikStik Eval board's external debugging option. Is it Okay to use that K40 KwikStik as debugger?

Please guide us to get back the processor.

Thanks & Regards,

Yasar Arafath

[kerryzhou]

Hi Yasar Arafath,

1. If the JLINK commander unlock way also can't be success, your chip maybe damaged.

   Now, how many chips have this problem on your side?

   If the chip is damaged by the power up sequence, it is hard to recover.

2. From the quick start guide for kwikstik

  The on-board JLINK progammer can program the external MCU, to program an external MCU, a JTAG connector must be placed on J8 and the ON/OFF switch must be in the OFF position to deactivate the K40X256 MCU.

3.   Please refer to the document which I give you, page 4, <2> Power up sequence.

   if reset pin power up earlier than VDD, it will lock the chip and hard to recover. It must be careful to check the power up sequence with power circuit or programmer tool.

    Besides, find a new board, and don't connect the JTAG reset pin to your KL board, just to exclude the debugger problem. Then please check the power up sequence with power circuit carefully, the reset pin can't be powered up earlier than VDD.

Have a great day,
Kerry

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[yasararafathcs]

Hi Zhou,

Once again thank you for the clarification.

1. We are having around 30 chips with same problem.

2. For the external debugging same method I followed same as you mentioned and same from KwikStik User guide.

3. This part we will check from our side and come back to you.

Thanks & Regards,

Yasar Arafath

[kerryzhou]

Hi Yasar Arafath,

 1. Do you mean around 30 chips all can work before, after working a couple of days, then connect the debugger and want to download code, it is secured?

  Please also take care of the power on sequence when do downloading:

 Power on:

  (1) power off the board, connect the SWD or JTAG interface to your board.

  (2) power on the debugger

  (3) power on the board

Power off:

 (1) power off the board

 (2) power off the debugger and disconnect the debugger.

After download the code and run the board, don't connect the debugger. Please take care the debugger power on sequence.

2, Just as I have suggest, don't connect the reset pin in your board with the KwikStik Jlink.

3. Waiting for your reply!

Besides, NMI add 4.7K to 10K pullup, just for working stable.

Have a great day,
Kerry

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