Logic GND or real HW GND?

hardware support
1

Hi guys,
I have mounted the sFOC-mini on the back of the ESP32 to have a nice compact footprint.
There is only one position with HW GND and adjacent 4 PWM pins on the ESP (GND,13,12,14,27)
The ESP32 really needs more GND pins, but I thought of a workaround.

In order to add another sFOC mini, would it be OK to use a GPIO pin driven LOW as logic GND?
It would have to sink the three PWM signals and the enable signal. The power stage of the mini would be connected to the 12V supply.

ESP32_back
ESP32_back800Ă—570 129 KB

2

I guess these are high impedance inputs so there should not be a lot of current flowing, but something about doing that seems really wrong to me. Plus, it’s not “really” ground, since it is gated through a transistor, so while it would be ground potential it is still isolated from real ground.

I would try to solder a few wires into the ground pin of your ESP carrier board.

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3

Hey, no I wouldn’t do this. ESP32s are fussy anyway regarding voltages, I think this would be a way to get weird errors, or even damage the ESP32. I’d use a jumper wire.
But of course you can always try it out and see how it goes…

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4

I agree.
I could just use a 4-pin header and a jumper wire. Sounds much better.

Thanks
Olaf