Slow power up after NMI disable

[mircopizzichini]

Hi

Since I've to use NMI pin as GPIO, I disabled it writing 0xFB to address 0x0040 in flash configuration field. It works correctly, but the microcontroller power up is after about 4 seconds (both with and without j-link connected).

Now, if I try to revert my change (default was 0x3D), it never powers up!

How can I solve both situation?

Thank you

Mirco

[jeremyzhou]

Hi Mirco,

It seems so weird, and I was wondering if you can tell me what chip you use, then I can replicate the issue on my site.

I'm looking forward to your reply.
Have a great day,
Ping

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[mircopizzichini]

Hi Jeremy

I forgot to tell the chip... It's the KL03Z3VFK4, the same used on the FRDM-KL03Z.

I started with lptmr_example project: at first, with FOPT (in startup_MKL03Z4.S) at 0x3D, it started correctly... Then, since I wanted to disable NMI, I changed it to 0xFB, and that delay appeared.

If I go back to 0x3D, startup works correctly.

Let me know if you can replicate the issue, thank you.

Regards

Mirco

[jeremyzhou · Accepted solution]

Hi,

If the FOPT is configured as the 0xFB, then MCU will boot from the ROM, meanwhile it will be waiting for communication to begin on a peripheral until the detection times out, it needs some seconds.

So I think it's the root cause of the issue.
Have a great day,
Ping

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[mircopizzichini]

You're right, it's my fault!

I configure FOPT as 0x3B, disabling only NMI, and now it works properly.

Thank you

Mirco