MK60FX512VLQ12 Failure at boot - Constantly reset

[carloso]

Hi,

We're using MK60FX512VLQ12 on our board, in 8 boards we have a problem that cause a constantly reset after unlock the watchdog, we're using the same code of the BSP.

I'm attaching the waveform of the reset signal.

In 6 boards everything is working well, we have exactly the same hardware and firmware.

What could be the cause of this failure?

[victorjimenez]

Hello Carlos,

Please refer the following community post: https://community.nxp.com/message/632716 

Also depending on the mask of your MCU I highly recommend you to check the corresponding errata to see if any of the known issues is causing this behavior. 

Hope it helps!

Victor.

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[carloso]

Hi Victor,

I check the RCM_SRS register, indicates a core lockup.

The IPSR indicates a Hard Fault Mem Manage.

What could cause this hard fault?

We check the pull-up on reset_b and NMI pins ans everything is ok and we use the same clock configuration on all the boards.

[victorjimenez · Accepted solution]

Hello Carlos,

Since you are using your custom board and the problem you are facing is not in all your boards, it's not possible for me to reproduce the behavior you mentioned. 

Based on the information you provided, I suspect that you might have an out of spec clock configuration. Probably not very far out of spec, which is why it works on some parts and in some code configurations. I've seen similar behavior before when the flash clock is slightly higher than the rated frequency. Some devices can handle the higher frequency and might not show a problem at all, and other parts might only show an issue in specific cases depending on when/where code is being fetched from the flash.

Regards,

Victor.

[carloso]

Hi Victor,

Yes, the clock configuration was incorrect.

We have a 120MHz on core clock and a divisor of 4 on flash clock = 30MHz. When th max clock frequency for the flash is 25Mhz.

We change to 20HMhz and works now.

Thanks.