Help with some BLHeli pass-through

Xasin wrote 07/24/2019 at 07:57 0 points

I recently acquired a couple of ESCs and motors to restore an old RC Hovercraft of mine. 

My goal was to use an ESP32 as controller, and so far I've had very promising results using the LEDC module to generate OneShot125 PPM signals. 

There's just one problem:

The ESCs, running BLHeli_32, don't have reversing enabled, neither do I seem to be able to enter configuration mode by sending a maximum value PWM or PPM signal during initialization. That would have allowed me to enable thrust reversing. 

Now, I keep coming across BLHeli pass-through, which supposedly allows the flight controller to reconfigure the esc, probably via some sort of UART. 

But oh 

My 

God 

There is absolutely zero documentation on the actual communication protocol. 

If anyone has a link to the specs I would be incredibly grateful. Then I could hopefully just reconfigure the ESC from the ESP32

Oh, and before anyone asks, the ESC is a four in one, with no exposed programming headers, so... I'm afraid I can't flash new firmware. Not that I don't want to...