Overview ESP32-DevKitC V4 is a small-sized ESP32-based development board. Most of the I/O pins are broken out to the pin headers on both sides for easy interfacing. Developers can either connect peripherals with jumper wires or mount ESP32-DevKitC V4 on a breadboard. Download button. Holding down Boot and then pressing EN initiates Firmware Download mode for downloading firmware through the serial port. Single USB-UART bridge chip provides transfer rates of up to 3 Mbps. USB interface. Power supply for the board as well as the communication interface between a computer and the ESP32-WROOM-32 module. 5V Power On LED Turns on when the USB or an external 5V power supply is connected to the board. For details see the schematics in Related Documents. I/O Most of the pins on the ESP module are broken out to the pin headers on the board. You can program ESP32 to enable multiple functions such as PWM, ADC, DAC, I2C, I2S, SPI, etc. Power Supply Options There are three mutually exclusive ways to provide power to the board: Micro USB port, default power supply 5V and GND header pins 3V3 and GND header pins