Usb Troubleshooting - LG CU920 Manual

4.12 USB Troubleshooting

USB Initial sequence is :
USB connected to CU920 power on → USB_VBUS(U700) go to 5V → USB_D+ go to 3.3V →
USB_VP and USB_VN is triggered → USB work.
Start
Pow er is on?
Cable is inserted?
U700 2pin is 5V?
USB_D+ is 3.3V?
Chan ge the Ma in board
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Only for training and service purposes
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USB Troubleshooting Flow
- 115 -
Go to po wer on trouble shooting
Insert cable
Check U70 0 2Pin
Check U70 0
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