No COM port detected on Custom PCB

[rt2gaurav]

<r>I am using CP2102N-A02-GQFN24 on my custom PCB to program my ESP32 board. I am not able to see any COM port on my Windows 10 PC. I can connect to an off the shelf CP2102N-A02-GQFN28 USB UART bridge board to my computer. So I think that rules out driver issue then I am not really sure what else could be an issue. I was saw numerous people commenting on putting a 1-10uF cap on EN line of ESP32 to fix the timing issue or EN & IO0 line which is connected to RTS and DTR on CP2102 but that didn't help either. I can program my ESP32 if I connect COTS UART bridge board directly to ESP32 EN,IO0,Rx & Tx lines. Most of my schematics is similar to ESP32 Wroom Dev board which you can find in this link https://dl.espressif.com/dl/schematics/ ... v4-sch.pdf except I am using CP2102 24 pin package. I am not using buttons for manual programming but I am using NPN transistors SS8050-Ghttps://www.comchiptech.com/admin/files ... 181526.pdf for automatic bootloading. I have attached screenshot of my schematics. I have also attached timing snapshot from my OScope. In one snapshot DTR is CH1 & RTS is CH2 and in another snapshot IO0 is CH2 & EN is CH1. </r>

[ESP_Sprite]

If you don't have a COM-port show up, the issue is almost certainly between your PC and the CP2102.

[rt2gaurav]

I can program the board with COTS USB to UART board like this one which also has CP2102N chip so that means I have proper drivers in my PC. Only when I use it with my custom PCB I don't see any COM board.:
https://www.digikey.com/en/products/det ... EK/6605110

[rt2gaurav]

I got it fixed. I had schematic issue where my U6 ESD suppressor chip was not connecting the USB traces to the CP2102N chip. So I modified the boards to have proper ESD connection on pin 1 & pin 3 of my U6 chip.