Using a single MCU for a 4in1

[dzervas]

I’m designing an ESC and I have some questions:

• Can I use a single MCU (maybe an f3) with enough I/O (about 64)
• How many ADCs do I need per motor? My idea would be 3, for each phase, but from the BLHeli_S designs they don’t seem to be 3 ADCs. Do I just need to know that “some” current is passing or exactly the amount of current?
• Has anyone do that before? Is it much worse than a single MCU/motor in terms of frequency?
• Why does the current sensing circuitry use a GPIO as common and not ground?
• Is there any reference schematic?
• Is there any specific need for Ton/Toff/Tr/Tf? I found both 50-70ns and 5-10ns mosfets but the latter are much more pricier and can handle less current. For DShot1200, what are the max timing I’d need?
• In most schematics I see that the driver (FD6288Q) requires driving the current sensing back to it. Why is that (datasheet in chinese so I can’t quite understand it 😂)
• How can I calculate the dead time resistors in the mosfet gate? A random value of 25Ω was picked in a schematic I found