NodeMCU ESP32

All kinds of stuff about the NodeMCU ESP32

The NodeMCU ESP32 board (in some cases also known as ESP32-DevkitC) is fully supported by ESPHome. Simply select ESP32 when ESPHome wizard asks you for your platform and nodemcu-32s as board type.

# Example configuration entry 
esphome:  
name: 
	living room
esp32:  
board: 
	nodemcu-32s

The ESP32 boards often use internal GPIO pin numbering on board, this means that you don’t have to worry about other kinds of pin numberings.

30 Pin NodeMCU

Pins on NodeMCU ESP32 development board.

Note that in certain conditions you can use pins marked as INTERNAL in above image.

GPIO0 is used to determine boot mode on startup. It should therefore not be pulled LOW on startup to avoid booting into flash mode. You can, however, still use this as an output pin.
GPIO34-GPIO39 can not be used as outputs (even though GPIO stands for “general purpose input output ”…).
GPIO32-GPIO39: These pins can be used with Analog To Digital Sensor to measure voltages.
GPIO2: This pin is connected to blue LED on board as seen in picture above. It also supports touch pad binary sensor as do other pins marked touch in above image.
5V is connected to 5V rail from USB bus and can be used to power board. Note that UART chip is directly connected to this rail and you therefore cannot supply other voltages into this pin.

# Example configuration entry   
esphome:  gname: 
	livingroom 
esp32:  
board: 
	nodemcu-32s 
binary_sensor:  
       - platform: gpio    
gname: "Ping GPIO23"
pin:   GPIO23


Grn	Chk: Your first priority pins. They are perfectly fine to use
Yel:	Pay attention as their behavior can be unpredictable, mainly during boot. Don’t use them unless you absolutely need to
Red	X:It is not recommended to use these pins. So avoid them.

Label	GPIO	Safe to use?	Reason
D0	0	Yel	must be HIGH during boot and LOW for programming
TX0	1	Red	Tx pin, used for flashing and debugging
D2	2	Yel	must be LOW during boot and also connected to the on-board LED
RX0	3	Red	Rx pin, used for flashing and debugging
D4	4	Grn
D5	5	Yel	must be HIGH during boot
D6	6	Red	Connected to Flash memory
D7	7	Red	Connected to Flash memory
D8	8	Red	Connected to Flash memory
D9	9	Red	Connected to Flash memory
D10	10	Red	Connected to Flash memory
D11	11	Red	Connected to Flash memory
D12	12	Yel	must be LOW during boot
D13	13	Grn
D14	14	Grn
D15	15	Yel	must be HIGH during boot, prevents startup log if pulled LOW
RX2	16	Grn
TX2	17	Grn
D18	18	Grn
D19	19	Grn
D21	21	Grn
D22	22	Grn
D23	23	Grn
D25	25	Grn
D26	26	Grn
D27	27	Grn
D32	32	Grn
D33	33	Grn
D34	34	Yel	Input only GPIO, cannot be configured as output
D35	35	Yel	Input only GPIO, cannot be configured as output
VP	36	Yel	Input only GPIO, cannot be configured as output
VN	39	Yel	Input only GPIO, cannot be configured as output

ESP32 GPIO Pins

ESP32 development board has 25 GPIO pins which can be assigned to various functions programmatically. Each digital enabled GPIO can be configured to internal pull-up or pull-down, or set to high impedance.

Which ESP32 GPIOs are safe to use?

Because the ESP32 has many pins with specific functions, they may not be suitable for your projects. The following table shows which pins are safe to use and which pins require more attention before using them.

Input Only GPIOs

Pins GPIO34, GPIO35, GPIO36(VP) and GPIO39(VN) cannot be configured as outputs, they can be used as either digital inputs, analog inputs, or for other unique purposes. Also note that they do not have internal pull-up or pull-down resistors, like the other GPIO pins.

Also pins GPIO36(VP) and GPIO39(VN) are an integral part of the ultra-low-noise pre-amplifier for the ADC, which help to configure the sampling time and noise of the pre-amp.