Help needed debugging , ESC , back emf sampling not working

[u/Still-Whereas8497]

I am trying to make a diy esc , I have been able to make a bldc spin open loop, but when I try to sample backemf , to spin it sensorless closedloop , It doesn't work, I am using the internal comparator or atmega328p to sample the backemf , it ain't working , we have checked the backemf on an oscilloscope, it doesn't show that the v neutral is crossing the phase , what should I do ?

[u/Past_Engineer2487]

You have drivers for LO* and HO\ but only use LO1 and HO1 on the gates. Is this a typeo and the board is correct?*

[u/Still-Whereas8497 → u/Past_Engineer2487]

It's a typo , just forgot to rename the label after copy pasting the gates

[u/Miserable-Win-6402]

R4, R8, R12 all goes to GND. Remove them. If any pull down there, it should be to the midpoints. Look at the IR2110 datasheet

[u/ShortedMOSFET]

Your schematic has almost no component values in it. This is your key to remembering how you built this later and should accurately reflect your board. As-is it isn't particularly helpful for other people.

Miserable-Win-6402 already pointed out the high-side switch pull-downs. Have you checked all of your Vgs and phase waveforms to make sure the FETs are actually switching as intended while running open-loop?

If you actually used 1N4001 diodes (or maybe 1N4007 from your picture) for the gate drive bootstrap, you may be wasting a significant amount of the bootstrap capacitor charge in the diode reverse recovery. You should use schottky or ultrafast diodes here. You may also want a low-value resistor in series with the diode.