Can the built-in high-speed CR be selected for Master Clock when using the USB Function? - KBA218388

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    Question:

    When using the USB function, can we select the built-in high-speed CR for the master clock? 

     

    Answer:

    No. The high-speed CR clock (CLKHC) frequency accuracy does not meet the required USB specification. Also, EthernetMAC, CAN/CAN-FD, and I2S block cannot be used in this case. Refer to the FMx Peripheral Manual (Communication Part) for more notes on when to use high-speed CR for the master clock.