4. TROUBLE SHOOTING
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Cable is inserted?
Insert cable
No
Yes
Change the mainboard
C719(TP1) is 5V?
Check MUIC or Charger IC
No
Yes
USB_D+ (TP2) is 3.3V?
Check IC701
No
Yes
START
4.10 USB Trouble shooting
The sequence of LGP768USB is,
USB connected to LGP768 -> USB_VBUS(C716)goes to 5V -> USB_D+ go to 3.3V-> USB_DATA is triggered -> USB work
Block Diagram of USB & UART connection is shown below
4.11 USB Trouble shooting
The sequence of LGP760USB is,
USB connected to LGP760
USB_VBUS(C716)goes to 5V
USB_D+ go to 3.3V
USB_DATA is triggered
USB
work
Block Diagram of USB & UART connection is shown below
Check MUIC or
Charger IC
Insert
cable
NO
C719(TP1)
is 5V?
YES
YES
Cable is inserted?
NO
Check
IC701
Change the Main board
NO
YES
Start
USB_D+(TP2) is
3.3V?