Program and debug problems with KL15

[michaeltreumann]

Hi all,

I have a board designed with a KL15Z128. My problem is that I can program the controller only sporadically and debug. I have find out that when the programmierrung failed, the reset line toggeld. If programming was successful, the reset line is high.

I also have a crosstalk of the clock line to the reset line

If a program is in the controller I have no problems to debug.

I use the J-Link debugger.

Here's what I've already tried:

Reset line pulled up.

SWDIOLeitung pulled up.

Capacitor between Reset and GND.

Unfortunately, all without success.

Does anyone have any idea what this problem is?

[Jorge_Gonzalez]

Hello Michael Treumann:

Can you share your board schematics or at least the part of the SWD connections?

The reset pin toggling is the normal behavior for a blank device.

Also, you see "crosstalk" between the clock line and reset lines. Check that there is not any kind of short circuit between these pins.

Some things you can check and design tips that have helped other customers to have a more stable SWD connection:

- Check that the MCU is well soldered (no loose pins or defective solder joints).

- Try placing a series resistor in the SWD-CLK pin.

- A pull-up resistor is recommended in the SWD_DIO line.

- In the Reset line, connect a pull-up resistor to VDD and a capacitor to GND.

- Check that the NMI pin (PTA4 in your case) is not pulled low by any external signal.

Let us know if any improvement.

Regards!,
Jorge Gonzalez

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