If you want to use CAN bus for making communication happen between the FRDM-K64F boards, CAN Transceiver is needed.
There is flexcan interrupt_transfer example in SDK_2.5.0 of twrk64f120m.
You can see this example need Two TWR-SER boards in readme file.(The CAN Transceiver is on TWR-SER board)


Best Regards,
Robin
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