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K10 custom board

Question asked by Jon Gronholz on Jan 27, 2014
Latest reply on Jan 29, 2014 by Jon Gronholz

I'm developing a custom board for the MK10DX128VFM5 (QFN-32 with thermal). This is my first QFN so i chose the smallest pin-count, which also works well with the project requirements (being tiny/minimalist). I ordered 3, expecting to screw up and/or destroy the first two while getting familiar with soldering them. I was expecting this chip to be so super-easy that I soldered all of the components to the first board; i.e. crystals and all. The boards after the first were assembled with only the minimal components.


Initially, I tried using the FRDM-25Z with (Freescale)OpenSDA, (P&E)OpenSDA, USBDM.

  • For every assembled board and FRDM-25Z firmware combination, I tried both JTAG and SWD.
  • No combination of anything worked. Paraphrased, the error message was always "It didn't work", of which I was already vastly aware.
  • If I remove the debug cable and apply J11 to the FRDM board, all combinations of the above successfully deploy to the KL25Z and halt at main().
  • With my custom board reconnected, any combination of pull-ups/downs recommended by ARM and/or Freescale made no difference.


I drove to Mouser and got a P&E Multilink-U (>$100), 2 additional processors ($6), and a few other spare parts.

  • Going through all of the above again with the Multilink gave similar non-results.


I've switched back to the FRDM board for debugging, and inserted a small breadboard in the middle of my debug cable to allow me to:

  • Reconfigure pull-ups/downs
  • Source power to my board from the 25Z (or not)
  • Provide the reference voltage from my board to the Multilink-U


Searching for schematics/designs relevant to the K10 produced mostly irrelevant/ambiguous results, like the K20 development board, which has two K20's, USB, and a full loadout of bells and whistles, none of which has anything to do with the K10. After wasting all this time, what seems to be the most relevant results are the errata.


I've worked extensively with pre-made boards and modules so I suppose I'm spoiled on being able to just hook up some jumper wires and it work.

  • I've already revised my board layout to more closely mimic the target portion of the FRDM board, isolate power domains, etc.
  • I've wasted a bunch of money/uC's
  • I've replaced my perfectly good, open-source debugger with an expensive "professional" debugger for no reason
  • There is a ~2 week turnaround on new boards so I would like to get this next design "perfect"


I will reply to myself to create a separate "thread" for each related issue.