Custom RT1021 board no SWD connection

[f_und_e]

Hi there,

I am currently spinning a custom RT1021 board. Sadly, I cannot access the MCU via swd - jlinkexe does not find anything, only reports an undervolt error. Works fine with the evk board tho.. Maybe I made a mistake with the schematic, can anyone please help me? That would be very kind.

The 3.3V voltage rail is stable. I am not using POR B for any resets and left it floating. 1V1 works, aswell as the oscillators.

Thank you very much in advance!

[Omar_Anguiano]

Hello
I hope you are well.

It is important to assure that your design complies with the power-up sequence. It is highly suggested to use an IC to control the POR_b signal so we assure it remains asserted during the power-up sequence.
Please compare your design with the guidelines from the Hardware Development Guide.

Best regards,
Omar