Hello,

I am on my wits end trying to debug my usb-c socket/usb-otg port o nthe esp32-s3 and why it is not appearing on my laptop as a COM port for programming. I made a custom board for the first time using the esp32-s3. Since the esp32 s3 has built in D+ and D- lines for flashing firmware and debugging, I hooked up the USB-C connector directly to these pins via an ESD diode. On assembling the board, I cannot get myself to program the board via the USB-C cable. I have verified the the cable is perfect and is a data cable. I have probed the continuity from the USB-C receptacle to the esp32 and it is fine. I also probed the voltages on the lines to confirm the D+ line is being pulled high. I am however able to program the board via an external serial programmer via UART and can confirm that the board is able to go into download mode. I made a rookie mistake of not routing both D+ and D- lines together and hence can use it in only one orientation. I am attaching the layout and schematics below. Any help on what could be wrong is appreciated.

The only reason I can think of is that I messed up the routing of the USB lines.

 

Welcome to AAC.

The D+/D- lines are insufficient, you must also properly terminate the CC1/CC2 lines for the behavior you want.

The CC line on a USB-C connector establishes role and orientation. The host presents a pull-up (Rp) on CC1 and CC2; the device presents a 5.1 kΩ pull-down (Rd) to ground.

When one CC detects a valid voltage level, the host enables VBUS and data. The active CC defines plug orientation; the inactive line is ignored. Without this termination, no connection is recognized and D+/D− remain dead on the host side.

 

Welcome to AAC.

The D+/D- lines are insufficient, you must also properly terminate the CC1/CC2 lines for the behavior you want.

The CC line on a USB-C connector establishes role and orientation. The host presents a pull-up (Rp) on CC1 and CC2; the device presents a 5.1 kΩ pull-down (Rd) to ground.

When one CC detects a valid voltage level, the host enables VBUS and data. The active CC defines plug orientation; the inactive line is ignored. Without this termination, no connection is recognized and D+/D− remain dead on the host side.

I have included the 5.1k pull down resistors on my device though. It is there in my schematic. And I am assuming the the host i.e my laptop has the necessary hardware. I want to ask on a side not if it is ok to route the lines between the pads of the diode?

 

Have you tested with more than one cable?