Problem flashing for the first time

[buca]

Dear community,

in aspiration to lose the fog of my current ignorance, I appreciate any help to get back on track.

TL;DR

Can't get my Kinetis KL27 custom board to do anything.

No USB Enumeration / SWD (J-Link) detects secured device.

At POR RESETb gets pulled down internally after short strobe (~1ms). Could this be the watchdog in action?

Please let me guide you to my current setup.

Following some schematics. VDD = 3.3V.

Following the first Power-on, no USB-Enumeration happened. Examining closer the isolated MCU consumes 3mA @ 3.3V. Strangely RESETb is pulled low. As is the J-Link probes orange LED indicating.

J-Link command

> JLinkExe -if swd -device MKL27Z64XXX4 -speed 1000

followed by

>> connect

outputs

Device "MKL27Z64XXX4" selected.
Found SWD-DP with ID 0x0BC11477
Secured Kinetis device detected. For debugger connection the device needs to be unsecured.
Device will be unsecured now.
Note: Unsecuring will trigger a mass erase of the internal flash.
Found SWD-DP with ID 0x0BC11477
Secured Kinetis device detected. For debugger connection the device needs to be unsecured.
Device will be unsecured now.
Note: Unsecuring will trigger a mass erase of the internal flash.
****** Error: Kinetis (connect): Timeout while unsecuring device. Erase never starts.
Kinetis (connect): Failed to unsecure Kinetis device.

Please help me resolve this situation and uncover any design flaws. Any help is really appreciated.

Thank you in advance!

cheers,

Luca

[kerryzhou]

Hi Buca Zeug,

    Please do some modification to your board:

    1. Reset pin, Add 4.7K to 10K pullup resistor in the reset pin, and connect 0.1 uf capacitor to ground.

    2, NMI pin, add 4.7K to 10K pullup resistor.

  To a new chip, the Reset have the sawtooth wave is correct, after the chip is programmed, the reset pin will be pulled up.

  After you modify the board, use the JLINK COMMANDER to check whether it can dedicate the ARM core M0+.

  Besides, what the solder temperature when you soldering your chip to the board? From the datasheet, the solder temperature should below than 260 °C

Wish it helps you!

If you still have question, please contact with me!

Have a great day,
Jingjing

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