VDD Less than 2 V in USB-Serial Devices - KBA218338

Version 2

    Version: **

     

    Translation - Japanese:  USBシリアルデバイスでVDDが2 V未満 - KBA218338 - Community Translated (JA)

     

    Question:

    Why is the USB-Serial device not recognized after enabling "VDD less than 2 V" in the Configuration Utility?

     

    Answer:

    The 1.8-V internal regulator is enabled by default in USB-Serial bridge controllers. If you are supplying 1.8 V as VDDD/VCCIO, make sure you also connect the VCCD pin of the device to 1.8 V, to bypass the regulator. Then, select “VDD less than 2 V” in the Configuration Utility.

     

    When the VCCD pin is connected to 1.8 V, the USB-Serial bridge controller enumerates.