ESP32 Pinout Reference
Tutorial-for-ESP32-Pinout-Reference
	
One of the advantages of the ESP32 is that it has a lot more GPIOs than the
ESP8266. You won’t have to juggle or multiplex your IO pins. However,
there are a few things to keep in mind, so please read the pinout
carefully.


Note:

Please note that the following pinout reference is for the popular 30-pin
ESP32 devkit v1 development board.
	
30pin esp32 dev board

Not every ESP32 development board exposes every pin, but each pin works
exactly the same no matter which development board you use.




ESP32 Peripherals and I/O

Although the ESP32 has 48 GPIO pins in total, only 25 of them are broken
out
to the pin headers on both sides of the development board. These pins can
be
assigned a variety of peripheral duties, including:



15 ADC channels
15 channels of 12-bit SAR ADC with selectable ranges of 0
-1V, 0-1.4V, 0-2V, or 0-4V
2 UART interfaces
2 UART interfaces with flow control and IrDA support
25 PWM outputs
25 PWM pins to control things like motor speed or LED
brightness
2 DAC channels
Two 8-bit DACs to generate true analog voltages
SPI, I2C and I2S interface
Three SPI and one I2C interfaces for
connecting
various sensors and peripherals, as well as two I2S interfaces for adding
sound to your project
9 Touch Pads
9 GPIOs with capacitive touch sensing


Thanks to the ESP32’s pin multiplexing feature, which allows multiple
peripherals to share a single GPIO pin. For example, a single GPIO pin can
act as an ADC input, DAC output, or touch pad.

For extensive information about the ESP32, please refer to the datasheet.
ESP32 Datasheet


ESP32 Pinout

The ESP32 DevKit V1 development board has 30 pins in total. For
convenience,
pins with similar functionality are grouped together. The pinout is as
follows:
	
	
ESP32 Pinout

Let’s take a closer look at the ESP32 pins and their functions one by
one.


GPIO Pins

The ESP32 development board has 25 GPIO pins that can be assigned different
functions by programming the appropriate registers. There are several kinds
of GPIOs: digital-only, analog-enabled, capacitive-touch-enabled, etc.
Analog-enabled GPIOs and Capacitive-touch-enabled GPIOs can be configured
as
digital GPIOs. Most of these digital GPIOs can be configured with internal
pull-up or pull-down, or set to high impedance.
	
ESP32 GPIO Pins


Which ESP32 GPIOs are safe to use?

Although the ESP32 has a lot of pins with various functions, some of them
may not be suitable for your projects. The table below shows which pins are
safe to use and which pins should be used with caution.
 
– Your top priority pins. They are perfectly safe to use.
– Pay close attention because their behavior, particularly during
boot, can be unpredictable. Use them only when absolutely necessary.
– It is recommended that you avoid using these pins.




Label
GPIO
Safe to use?
Reason
D0
0
must be HIGH during boot and LOW for programming
TX0
1
Tx pin, used for flashing and debugging
D2
2
must be LOW during boot and also connected to the on-board LED
RX0
3
Rx pin, used for flashing and debugging
D4
4

D5
5
must be HIGH during boot
D6
6
Connected to Flash memory
D7
7
Connected to Flash memory
D8
8
Connected to Flash memory
D9
9
Connected to Flash memory
D10
10
Connected to Flash memory
D11
11
Connected to Flash memory
D12
12
must be LOW during boot
D13
13

D14
14

D15
15
must be HIGH during boot, prevents startup log if pulled LOW
RX2
16

TX2
17

D18
18

D19
19

D21
21

D22
22

D23
23

D25
25

D26
26

D27
27

D32
32

D33
33

D34
34
Input only GPIO, cannot be configured as output
D35
35
Input only GPIO, cannot be configured as output
VP
36
Input only GPIO, cannot be configured as output
VN
39
Input only GPIO, cannot be configured as output

The image below shows which GPIO pins can be used safely.
	
	ESP32 GPIO Pins that are Safe to Use



Input Only GPIOs
Pins GPIO34, GPIO35, GPIO36(VP) and GPIO39(VN) cannot be configured as
outputs. They can be used as digital or analog inputs, or for other
purposes. They also lack internal pull-up and pull-down resistors, unlike
the other GPIO pins.


ESP32 Interrupt Pins

All GPIOs can be configured as interrupts. For more information, please
refer to this tutorial.
ESP32 Tutorial For GPIO Interrupt Handling
Configuring & Handling ESP32 GPIO Interrupts In Arduino IDE
Often in a project you want the ESP32 to perform its normal program while 
continuously monitoring for some kind of event. One widely adopted solution...



ADC Pins
ESP32 integrates two 12-bit SAR ADCs and supports measurements on 15 channels 
(analog-enabled pins).
	

The ESP32’s ADC is a 12-bit ADC, which means it can detect 4096 (2^12) discrete
analog levels. In other words, it will convert input voltages ranging from 0 to
3.3V (operating voltage) into integer values ranging from 0 to 4095. This 
results in a resolution of 3.3 volts / 4096 units, or 0.0008 volts (0.8 mV) per
unit.

Moreover, the ADC resolution and channel range can be set programmatically.

Warning:
The ADC2 pins cannot be used when Wi-Fi is enabled. If your project requires Wi-Fi, consider using the ADC1 pins instead.




DAC Pins
The ESP32 includes two 8-bit DAC channels for converting digital signals to true
analog voltages. It can be used as a “digital potentiometer” to control analog
devices.
	
	ESP32 DAC Pins

These DACs have an 8-bit resolution, which means that values ranging from 0 to
256 will be converted to an analog voltage ranging from 0 to 3.3V.

The DAC’s 8-bit resolution may be insufficient for use in audio applications, in
which case an external DAC with a higher resolution (12-24 bits) is preferable.


Touch Pins
The ESP32 has 9 capacitive touch-sensing GPIOs. When a capacitive load (such as 
a human finger) is in close proximity to the GPIO, the ESP32 detects the change 
in capacitance.
	
	ESP32 Touch Pins

You can make a touch pad by attaching any conductive object to these pins, such
as aluminum foil, conductive cloth, conductive paint, and so on. Because of the
low-noise design and high sensitivity of the circuit, relatively small pads can
be made.

Additionally, these capacitive touch pins can be used to wake the ESP32 from 
deep sleep.


I2C Pins
The ESP32 has a single I2C bus that allows you to connect up to 112 sensors and
peripherals. The SDA and SCL pins are, by default, assigned to the following 
pins. However, you can bit-bang the I2C protocol on any GPIO pins with the wire.
begin(SDA, SCL) command.
	
	ESP32 I2C Pins



SPI Pins
ESP32 features three SPIs (SPI, HSPI, and VSPI) in slave and master modes. These
SPIs also support the general-purpose SPI features listed below:

4 timing modes of the SPI format transfer
Up to 80 MHz and the divided clocks of 80 MHz
Up to 64-Byte FIFO


	
	ESP32 SPI Pins

Only VSPI and HSPI are usable SPI interfaces, and the third SPI bus is used by 
the integrated flash memory chip. VSPI pins are commonly used in standard 
libraries.

HSPI vs. VSPI
HSPI is sometimes misinterpreted as “Hardware” SPI and VSPI as “Virtual or 
Software” SPI. In reality, however, they are identical!  

As with I2C, you can bit-bang the SPI protocol on any GPIO pins with the 
	bus.begin(CLK_PIN, MISO_PIN, MOSI_PIN, SS_PIN); command.



UART Pins
The ESP32 dev. board has three UART interfaces, UART0, UART1, and UART2,
that support asynchronous communication (RS232 and RS485) and IrDA at up to
5 Mbps.

UART0 pins are connected to the USB-to-Serial converter and are used
for
flashing and debugging. Therefore, the UART0 pins are not recommended for
use.
UART1 pins are reserved for the integrated flash memory chip.
UART2, on the other hand, is a safe option for connecting to UART
-devices such as GPS, fingerprint sensor, distance sensor, and so on.

	
	ESP32 UART Pins
In addition, UART provides hardware management of the CTS and RTS signals
and software flow control (XON and XOFF) as well.



PWM Pins
The board has 21 channels (all GPIOs except input-only GPIOs) of PWM pins
controlled by a PWM controller. The PWM output can be used for driving
digital motors and LEDs.
	
	ESP32 PWM Pins

The PWM controller consists of PWM timers, the PWM operator and a dedicated
capture sub-module. Each timer provides timing in synchronous or independent
form, and each PWM operator generates a waveform for one PWM channel. The
dedicated capture sub-module can accurately capture events with external timing.



RTC GPIO Pins
Some GPIOs are routed to the RTC low-power subsystem and are referred to as
RTC GPIOs. These pins are used to wake the ESP32 from deep sleep when the
Ultra Low Power (ULP) co-processor is running. The GPIOs highlighted below
can be used as external wake up sources.
	
	ESP32 RTC GPIO Pins



Strapping Pins
There are five strapping pins: GPIO0, GPIO2, GPIO5, GPIO12, and GPIO15.
	
	esp32 strapping pins
These pins are used to put the ESP32 into BOOT mode (to run the program
stored in the flash memory) or FLASH mode (to upload the program to the
flash memory). Depending on the state of these pins, the ESP32 will enter
BOOT mode or FLASH mode at power on.

On most development boards with built-in USB/Serial, you don’t need to
worry about the state of these pins, as the board puts them in the correct
state for flashing or boot mode.

However, if peripherals are connected to these pins, you may encounter
issues when attempting to upload new code or flash the ESP32 with new
firmware, as these peripherals prevent the ESP32 from entering the correct
mode.

The strapping pins function normally after reset release, but they should
still be used with caution.



Power Pins
There are two power pins: the VIN pin and the 3V3 pin. The VIN pin can be
used to directly power the ESP32 and its peripherals, if you have a
regulated 5V power supply. The 3V3 pin is the output from the on-board
voltage regulator; you can get up to 600mA from it. GND is the ground pin.
	
	ESP32 Power Pins



Enable Pin

The EN pin is the enable pin for the ESP32, pulled high by default. When
pulled HIGH, the chip is enabled; when pulled LOW, the chip is disabled.

The EN pin is also connected to a pushbutton switch that can pull the pin
LOW and trigger a reset.
	
esp32 enable pin