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Only for training and service purposes
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4. TROUBLE SHOOTING
4.11 USB Troubleshooting
USB Initial sequence is :
USB connected to I/O connector
Æ
USB_VBUS(U504) go to 5V
Æ
USB_D+ go to 3.3V
Æ
USB_VP and USB_VN is triggered
Æ
USB work.
NO
YES
YES
NO
YES
NO
YES
NO
[ USB Troubleshooting Flow ]
Start
Change the main board
Connect USB cable
Go to Power on trouble shooting guide
Check the USB cable
Check the USB cable
Cable is connected ?
Power is ON ?
U504 #2pin is 5V ?
USB_D+ is 3.3V ?