I bought a ESP-32 development board and I'm having a lot of trouble with a button on the GPIO00 pin. This is a strapping pin on the ESP32 chip; when set to LOW on startup, the chip enters the bootloader. There's a convenient button on the development board.
In the schematic for the dev board, there's a 12k pull-up resistor between GPIO00 and 3.3V, and 470ohm between GPIO00 and the button; the button connects to ground. I confirmed this with my multimeter. Given that, I'd expect to read 0.12V when pressing the button. Instead I read 1.33V! This is outside the spec for the low-level digital input, though it seems to enter the bootloader properly.
Does anyone know why there's such a high voltage when pressing the boot button (GPIO00)? Is there anyway to mitigate this if I want to connect my own button to GPIO00?