AnsweredAssumed Answered

Cannot program MK64FN1M0M12. Reset problem.

Question asked by Roth Kalman on May 16, 2017
Latest reply on May 19, 2017 by Roth Kalman

Hello everyone!


I have just produced a board which uses a MK64FN1M0VLQ12 chip.

The problem is that the chip's reset pin stays low after POR, and I cannot figure out how could I achive to pull its pin high.

The power supply of the chip seems to be ok, the reset pin is tighted through 1K resisitor towards positive rail, and through 100 nF cap to ground.


I am trying to probram my chip using FRDM-K64F board, but as soon I plug its SWD socket, the programmer's reset LED turns on, signing that the common reset line is low. So at this point I have no chance to program the chip.


I think I can rule out systematic hardware failure, the reset pin is not shorted toward ground, the power supplying shall be fine.


My question is, what can lead for this chip to hold its reset pin low?


Some additional info:

Chip is supplied from 3.3 V LDO. I have tried decreasing power up slew rate with a serial 33 Ohm and parallel 20 uF cap. But it doesn't help at all.


The Vregin and vout33 pins tighted through 10 k resistor to ground.


In a previous design this power scheme was used, and it worked.


I am looking forward for some help from NXP support team as well!

Thank you in advance!