I am not confident I can add anything to gpio.0 and not mess up the USB control. I know the RTS can pull gpio.0 low to enter programming mode but how strong is it pulling? Wrong pull up on my end and that doesn’t work. That also leaves me with a reverse logic pin, the other three will be low triggering high. This is too far over my head, esp32 boot, boot button, USB logic, buffer all on one pin.
Options seem to be;
1- Don’t use it.
2- Leave it floating, use :pd so after boot the pin pulls itself low, the other three output pins will actually be pulled down. Leaves us with one uncertain pin at boot, the other three should be stable.
3- Use the buffer enable. To use the enable feature we would need a timed output so it would not cost us a pin to use, as I am not seeing any other pins that pull low after boot.I still don’t see how to use a pulled up gpio.0 to work with this buffer (is there a reverse logic buffer?), it leaves me with an always on pin that can switch off after boot? What value pull up?