Board Bring-up: MKL14Z reset pin always low

[brianwang]

Hello all,

We made a custom board with a MKL14Z32VLK4 on it.  However, it is not coming out of reset.

The reset pin is constantly driven low.  We have separated the reset pin from the rest of the circuit

and figured it is the MKL14Z32VLK4 that is driving it low.  It is suspected that some POR condition

has not been met but we do not know what it is...

The user manual states:

When Flash Initialization completes, the RESET pin is released. If RESET continues

to be asserted (an indication of a slow rise time on the RESET pin or external drive

in low), the system continues to be held in reset. Once the RESET pin is detected

high, the Core clock is enabled and the system is released from reset.

Adding a pull-up 10k ohm resistor and a decoupling 1uF cap to the ground at the reset pin does not help.

Please note that there is no crystal at XTAL and EXTAL as I assume the chip would work fine out of its internal clock.

Any pointers are greatly appreciated.

Thanks in advance.

Brian

[perlam_i_au]

Is your RESET signal just in low level? have you seen the RESET pin signal using an oscilloscope? I ask this because if your pin signal is oscillating it could mean your code is not running and the watchdog resets your device all the time.

Have a nice day :P,
Perla

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