Tool/software:
Dear Sir,
We have designed a system in which we are using USB HUBs consisting of 4 downstream ports. Out of which we are using only 2 downstream ports, and the other 2 are unused and terminated by a 15k ohm resistor. One port of our USB HUB is connected to the MSP430 controller USB ports pin, and the other port, i.e., port no. 2, is connected to the CP2102N USB to UART converter. Both downstream devices are getting 5V through a load switch for their USB operation power, as shown in the schematic. Actually, there are two issues that I am facing and want some help from you to resolve them. The issues listed below:
1) Initially after powering my system, the voltage observed at TP21 & TP23 is 0V and at TP22 & TP24 is 3.28v which is correct as I haven't connected any USB device to the USB-C connector. When I connect USB-C cable to my PCB and other end to laptop in that case the voltage observed at TP21 & TP23 is 5v and TP22 & TP24 is 0v which is also correct. The issues that has been observed, when I removed my USB-C cable from USB-C connector ( keeping my system powered ON) a in that case the voltage observed at TP21 & TP23 is 5v (which should be zero) and voltage at TP22 & TP24 is 0V ( which should be 3.3v ). I don't know why this issue is occurring, after resetting the system the issue got resolved, i.e got perfect voltage. But this should got resolve without resetting my whole board as everytime sometime will not reset the board again & again. I have viewed the datasheet and also done a review of my design by TI all was okk. I have attached the schematic section of it, please review it and let me know if there are any faults.
2) The second issue is that in the working board, my USB HUB was working properly and detecting the downstream devices. The same board, after some time was unable to recognize my CP2102N USB to uart converter showing in device manager. The USB device descriptor request failed. I had also updated the CP2102 driver but still the same issue persists. I have also attached the screenshot of it; please have a look in to it.
3276.USB HUB SHEET.pdf
Waiting for your response,
Thanks & Regards,
Shubham
