Having trouble flashing a blank microcontroller

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Having trouble flashing a blank microcontroller

Contributor II

I have built my first PCB board and I have little to zero experience in flashing a blank board. The microprocessor that I have used is the MK64FN1M0VLL12 using the LQFP-100 pin package. I am programming it using MCUXpresso from NXP.
The issue that I am currently having is that the micro is constantly resetting approx every second or so. Using an oscilloscope I also cannot see any output clock output from pin 1. This makes me believe that the micro is having trouble powering up. I also have an external clock connected to the micro. Not sure if this impacts the clock on startup.
I also have questions about correctly initialising (enabling/disabling) the signals/clocks/hardware on MCUXpresso for the project. Also when I try to flash and debug the card as I go to step through the code I get a tab pop up saying "No source available for "g_pfnVectors() at 0x0". Is this bootloader related if so how do I add a bootloader? The dev board with this processor was set up as a mass storage device so you could drag and drop the bootloader.
Appreciate all feedback! TIA

Edit: Regarding setting up the bootloader, is this the right approach?  https://mcuoneclipse.com/2014/11/10/recovering-the-frdm-k64f-bootloader-or-cloning-the-program-of-a-...
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1 Reply

NXP TechSupport
NXP TechSupport

Hi Bouras,

  To a new K64 chip which still didn't download the firmware, the constantly resetting in the reset pin is correct, after you download the code, it will be high.

  Now, at first, I highly recommend you find a JLINK, and use the JLINK to connect your own designed board, use the JLINK command to check whether you can find the ARM core or not?

An example for you:


Please check it at first, if you can't find the ARM core, it means your hardware still have issues.

If you can find the ARM core, then you should can debug the code.

BTW, your hardware: NMI pin need to be pull up with 4.7K to 10K resistor, reset pin, 4.7K to 10K pull up, and 0.1uf capacitor to ground.

SWD_DIO pull up 10K.


Any updated information, just kindly let me know.

Best Regards,



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