ESP32 DevKit V1 Pinout: 30 vs 38 Pin Reference
Summary: ESP32 Pinout in 30 Seconds The ESP32 is Espressif’s dual-core Xtensa LX6 MCU running at up to 240 MHz with Wi-Fi and Bluetooth. The chip has 34 GPIOs; boards break out either 30 or 38 pins. The 30 vs 38 pin difference is not just pin count: six of the extra pins on the 38-pin board are wired to the internal flash and cannot be used. GPIO6 through GPIO11 belong to the flash chip. Connect anything there and the board will not boot. GPIO34, 35, 36 and 39 are input only. They cannot drive an output and have no internal pull-up or pull-down. GPIO0, 2, 5, 12 and 15 are strapping pins. Hold one at the wrong level during boot and the board either refuses to start or hangs in flashing mode. ADC2 does not work while Wi-Fi is on. Wire analog sensors to the ADC1 pins, GPIO32 to GPIO39. The board runs on 3.3 V logic and is not 5 V tolerant. Never wire a 5 V sensor output straight to a GPIO. The ESP32 is cheap, fast, and ships with Wi-Fi and Bluetooth built in. It also has one habit that drives beginners up the wall: the board says 38 pins, and you cannot use all of them. Wire a relay to one pin and the board stops booting. Wire a sensor to another and the reading turns to noise the moment Wi-Fi comes up. Wire an LED to a third and it flickers once on every reset. ...