AnsweredAssumed Answered

Kinetis K20DX256VLH7 doesn't work without JTAG/SWD connected.

Question asked by Atanas Tulbenski on Mar 25, 2015
Latest reply on Apr 1, 2015 by ZhangJennie



I'm having quite strange behavior on our custom K20DX256VLH7 based board. When debugging the project everything works fine, but when running from internal flash nothing works.

I'm using:

* OpenSDA debugger found on FRDM-K20D50M board (also tested with Segger JTAG)


* Project created through KDS wizard, flash debug configuration.

* Tried few examples provided with KDS/PE.


Tried all possible combinations of pull up/down resistors (10K) on JTAG/SWD pins.

Tried to remove the usage of "printf()" in case of semi-hosting issue, but nothing helps.

What makes things really strange is when run it from the debugger and then manually reset the MCU it works.


Any clue/idea will be appreciated!


Thank You!