Hi S.L.
If you use the IAR7.4 and the PE multilink univeral on the FRDM-K22 board, you should use the SWD interface, please configure your IAR like this:



But if you choose the OPENSDA in the FRDM-K22 bord, you should choose the CMSIS-DAP, not the PE opensda, because the debugger on this board is OPENSDA V2.1, it is the CMSIS-DAP.
Wish it helps you!
Have a great day,
Jingjing
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