is it necessary to use all pin of serial port.
i have just used rx and tx of serial.
power supply is given.
that all. no other connection i have done to board.
i found the solution .
the board had some missing component
usb port micro is solder.
r55 and r 56 are shorted (near usb micro)
r17 560ohm (betwenn ethernet and normal usb port)
zener 4.7v (option).(it is subtitue of TPD2EUSB30DRTR ). if u want to solder it.
connet zener anode to ground.
cathode must be connect to r17 (pin of r17 with is not conneted to usb 5v)
after that driver will be automatically detected . it will take time.
i advice on buy viola board.
use evaluation board.
i happen many time that new user just order which appear on home page as it happened to me.
the company has very good documentation . it help to solve my problem just reading the 3 4 pdf and circuit diagram