ESP32 Forum

Hello,

I have a project using an esp32C3 super mini board.
The problem is that I have 2 use cases.

In both cases, I have 12v comming in for the steper motors.

In use case 1 the system does not have a PC connection and the esp32 is powered from the external 12v through a dc-dc regulator to the super mini 5v pin.

In use case 2, the system does need a PC connection and the esp is connected to the PC using usb.

The problem is that they seems to be an issue with the usb connection when power comes from the 12v supply.
If the esp has power from the 12v, then usb connection does not work at all.
If the esp is first powered from usb, and the 12v external power gets turned on, usb sometimes works, sometimes disconnect.

Do you have any ideas why? and what would be the right way to get this working?
P.S: it's a usb-c connection
Thanks,
Cyrille

Hi,

More details, such as the schematics and wiring diagrams, would be nice.

Hello,

Here are the schematics:
Of interest, an esp32c3 super mini board in the center, which has a usb c connector with the usb 5v vbus exposed.
on the top left the 12v barel connector (VCC) which feeds in a 12-5v dc-dc convertor (just bellow it the schematics) which is connected to the super mini-5v. the 12v also powers the stepper sheilds.

The rest of the circuit has a keyboard on the left, 3 stepers sheilds on the right IC2 and serial connection to a LCD and a gps in the top/middle.

Case 1: the system is just connected to 12v. All works well.
Case 2: the system is just connected to the Pc through usb. all is good and the pc can talk to the esp. (In this case the motors are unpowered, but that is not a problem).
Case 3: 12v in + usb. Depending in the order in which I connect the 2, the PC either NEVER connects with the esp32 (12v first, then usb), or sometimes works, sometimes does not (usb first, then 12v, I hear the usb disconnect when I plug in the 12v, about 2/3 of the time).
Any clue how to fix this?