Hi Li
this may be caused by power up sequence, one can check
if voltages and clocks are stable when POR released, use
sect.4.2.1.1 Power-up sequence i.MXRT1050 Datasheet
https://www.nxp.com/docs/en/data-sheet/IMXRT1050CEC.pdf
and sect.6. Boot, reset, and miscellaneous Hardware Development Guide for
the MIMXRT1050 Processor
https://www.nxp.com/docs/en/user-guide/MIMXRT1050EVKHUG.pdf
Best regards
igor
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