The ESP32-DevKitC V4

Espressif's own ESP32 board: a WROOM-32 module on thirty-eight pins named by GPIO, with no user LED.

What it is

The same classic ESP32 as the ESP32 DevKit V1, on the board Espressif makes for it. Two nineteen-pin headers run down the long edges a full inch apart, so on a breadboard it covers every row but one; the micro-USB socket at the bottom goes through a USB-to-serial chip to UART0, which is the serial monitor. EN is the reset, and BOOT grounds GPIO 0.

The pins

The silkscreen numbers are the GPIO numbers, so a sketch writes 2 for GPIO 2.

Left	Right
3V3	GND
EN	23
VP (GPIO 36)	22
VN (GPIO 39)	TX (GPIO 1)
34	RX (GPIO 3)
35	21
32	GND
33	19
25	18
26	5
27	17
14	16
12	4
GND	0 (BOOT)
13	2
D2 (GPIO 9)	15
D3 (GPIO 10)	D1 (GPIO 8)
CMD (GPIO 11)	D0 (GPIO 7)
5V	CLK (GPIO 6)

34, 35, VP and VN are inputs only: there is no output driver on them, and the board shows an amber mark if a sketch tries. VP, VN and 32 to 35 are ADC1 and read the voltage on the net. I2C is on 21 and 22.

Six pins to leave alone

D0 to D3, CMD and CLK are the module's SPI flash. Espressif's user guide says not to use them, and here they are open: nothing drives them and no sketch can reach them.

There is no user LED

The one lamp on the board is the power LED. There is no LED_BUILTIN, as in the Arduino IDE's "ESP32 Dev Module", so a sketch that uses it does not compile. Wire an LED and a 220 ohm resistor to a pin instead; the built-in Blink uses GPIO 2.

WiFi

It joins Mokxi's simulated network, with the network name and password as properties of the board. There is no radio, no 802.11 and no real internet: Simulated WiFi says what is faithful and what is not. The one exception is the Real internet switch in the Cloud panel, which sends requests for other names out through Mokxi's gateway.

What is modeled

The DevKit V1 model's chip, whole: one Xtensa LX6 core, GPIO, UART0, the timers, ADC1 and LEDC PWM. Programs built for this board and for the DevKit V1 run on either; the two carry different program strings so each is offered its own examples.

What is not modeled

The second core, ADC2, the DAC, touch sensing, the flash lines toggling while the chip fetches code, and a real radio. Bluetooth Classic and LE are simulated: a phone in the editor's Bluetooth pane, not a real radio.

MicroPython

Pick MicroPython (main.py) in the board's Firmware panel and it runs the official MicroPython v1.29.0 firmware with your main.py. See MicroPython on the ESP32.

Starter project

DevKitC blink is the board across a breadboard with an LED and a resistor on GPIO 2.