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K22F Debug Interface

Question asked by Michael Schwager on Dec 28, 2015
Latest reply on Dec 29, 2015 by Michael Schwager

Hi, I would like to confirm the JTAG debug interface for MK22FN512VLH12.


Following is a snippet of schematic that has worked in the past for K60-based controllers, but this is a new chip for us, so I want to make sure.

I verified with "Debug interface.pdf" which was kindly posted to this forum by Ping in August of this year (2015), but the document does not specify the strength of the pullup/down resistors, nor the direction, for all three pins in question.


Fortunately, the document does specify that pin 10 of the JTAG connector goes to the microcontroller main reset.


The 3.3V I think is used as reference for the JLink adapter, so it goes *out* of my PCB, whereas of course the pins 11 and 13 come *into* the PCB.

The MCU_RESET signal has a 10k pullup elsewhere in the schematic, not shown here.


Therefore, following questions:

  • Can someone please confirm the usage of 3.3V, and also verify the below pullups/downs and pinouts are correct (for LQFP-64pin version)?
  • Can someone please confirm I can feed a 50MHz clock (standalone MEMs oscillator, not resonator or crystal) into the EXTAL0 (pin 32) of this K22F device?  The reference manual talks about 32MHz being the max, but I believe that is for a crystal; the FRDM board has the option of a 50MHz clock, and this oscillator has worked before for K60 designs.
  • Can someone please point me to the Freedom board schematic for K22F?  I found the hardware manual, etc., on the main page, but didn't see the schematic.
  • Is there a "clean" reference design (not part of Freedom board) that does not use the SDA SWD stuff?  This is where it becomes confusing a little.
  • Is there a checklist for K22F designs?




Thank you very much