Now I can't even connect to FRDM-KE04Z SWD via J-Link

[mikesilva]

Now that I've given up trying to do OpenSDA with a FRDM-KE04Z, I'm trying to connect a J-Link directly to the SWD port.  I added the header to the target chip (not the OpenSDA interface chip) and removed R35 (to isolate CLK) and R58 (to isolate RESET).  I'm using the correct 20-pin to 10-pin ARM interface, and even ohm-ed it out.  No connection.  J-Link LED twinkles orange, meaning RESET is asserted.  Put the scope on the RESET line and see a sawtooth waveform going between about 1V and 2V.  Where in the heck is that coming from?  I've pretty much decided to smash the FRDM-KE04Z into tiny pieces and lay out a simple board of my own, with just the Kinetis chip, SWD connector, and a bit of I/O.  This shouldn't be this hard!  What am I missing?  I'm really hoping it's just something I'm doing wrong.

[kerryzhou]

Hi Mike Silva,

    Thank you for your interest in NXP Kinetis product, I would like to provide service for you.

    1. Could you tell me why you don't use the on board OPENSDA?

      This debugger can use both opensda and JLINK firmware, you don't need to use external JLINK debugger.

    2. External JLINK debug connection

      If you want to use the JLINK, you also don't need to remove the component on the board, just connect your JLINK to the J8 is OK.

    Here take care, you said you use the correct 20-pin to 10 pin, please double check the pin wire, whether it is correct.

    After you connect the JLINK debugger, you can use the JLINK Command to check it, whether the ARM cortexM0+ can be found.

    3, Reset pin sawtooth waveform

    To a new chip which has no code in it, this phenomena is correct, after you download the code to it, the reset pin will be high.

Please double check your JLINK connection, because the JLINK debugger 20 pin interface is the standard ARM interface, but the FRDM-KE04 is not the standard interface, then you should convert the wire.

Wish it helps you!
If you still have question, please contact me!

Have a great day,
Jingjing

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------