Hi Wonjae,
Just few notes:
The RESET pin is tied down during power up until reset sequence is finished (512~768 PLL cycles) or until the VDDX voltage reach LVR deassert value (approximately 3.13V).
The picture just told you that debugger cannot establish connection with the MCU. It may not have any relation to the RESET pin status itself. Please check voltage levels and reset pin levels.
If you use external debugger interface like Multilink Universal, please check also BDM connector orientation (on both sides),…
Best regards
Radek
Hello,
There is a possibility that the MCU is reset repeatedly.
To verify, use an oscilloscope to measure voltage on the reset pin.
Best regards,
Diana