Hello: We has a pilot run 270 pcs boards (LPC55S28JEV98Y). And found 3 pcs boards failed at USB port function. The USB port function will be work once pull the reset pin to low (to reset the MCU). It seems the MCU is no startup properly while power on. Then MCU will be startup well after pull the reset pin to low. Checked the power and 16MHz crystal are correct. Could anyone can help give us some suggestions for the issue? Thanks for your help.
Test summary:
- Failed rate: 3/270
- Connected USB cable to PC
- The USB port : no function. (the power & clock is normal, the USB_DP is no active)
The PC will show USB port (USB function is working) once pull Reset pin to low (reset MCU).
3. Try to remove R201 & change C214 to 100nF (extend reset time. But, it still failed.
