The ESP32-S3 DevKitC is one of the most popular development boards with the ESP32-S3 chip. This chip comes with 45 pins and has a different pinout than the boards with the ESP-WROOM-32 chip. In this article, we’ll take a look at the ESP32-S3 DevkitC board Pinout and explain the different functions of its GPIOs.
ESP32-S3 Peripherals
The ESP32-S3 peripherals include:
- 20 Analog-to-Digital Converter (ADC) channels
- 4 SPI interfaces
- 3 UART interfaces
- 2 I2C interfaces
- 8 PWM output channel
- 2 I2S interfaces
- 14 Capacitive sensing GPIOs
Due to the ESP32 chip multiplexing feature, you can assign almost any function to the GPIO of your choice. However, there are pins with assigned functions by default. We’ll take a look at that in this pinout.
ESP32-S3 DevKitC-1 Pinout
The following picture shows the pinout of the ESP32-S3 DevKitC-1 board, one of the most popular development boards with the S3 chip. There are different versions of the same board with slightly different pinouts. Always double-check the pin location and the GPIO label before connecting any peripherals.
For more information about this board, check the official documentation here.
SPI Flash and PSRAM
GPIOs 26 to 32 are connected to the integrated SPI flash and PSRAM and are not recommended for other uses. They are not exposed in this particular board, but if they are exposed on your board, avoid using them:
- GPIO 26 (Flash/PSRAM SPICS1)
- GPIO 27 (Flash/PSRAM SPIHD)
- GPIO 28 (Flash/PSRAM SPIWP)
- GPIO 29 (Flash/PSRAM SPICS0)
- GPIO 30 (Flash/PSRAM SPICLK)
- GPIO 31 (Flash/PSRAM SPIQ)
- GPIO 32 (Flash/PSRAM SPID)
Capacitive touch GPIOs
The ESP32-S3 has 14 internal capacitive touch GPIOs. These can sense variations in anything that holds an electrical charge, like the human skin. So they can detect variations induced when touching the GPIOs with a finger. These pins can be easily integrated into capacitive pads and replace mechanical buttons. The capacitive touch pins can also be used to wake up the ESP32 from deep sleep.
Those internal touch sensors are connected to these GPIOs:
- T1 (GPIO 1)
- T2 (GPIO 2)
- T3 (GPIO 3)
- T4 (GPIO 4)
- T5 (GPIO 5)
- T6 (GPIO 6)
- T7 (GPIO 7)
- T8 (GPIO 8)
- T9 (GPIO 9)
- T10 (GPIO 10)
- T11 (GPIO 11)
- T12 (GPIO 12)
- T13 (GPIO 13)
- T14 (GPIO 14)
Analog to Digital Converter (ADC)
The ESP32 has 20x 12-bit ADC input channels. These are the GPIOs that can be used as ADC and respective channels:
- ADC1_CH0 (GPIO 1)
- ADC1_CH1 (GPIO 2)
- ADC1_CH2 (GPIO 3)
- ADC1_CH3 (GPIO 4)
- ADC1_CH4 (GPIO 5)
- ADC1_CH5 (GPIO 6)
- ADC1_CH6 (GPIO 7)
- ADC1_CH7 (GPIO 8)
- ADC1_CH8 (GPIO 9)
- ADC1_CH9 (GPIO 10)
- ADC2_CH0 (GPIO 11)
- ADC2_CH1 (GPIO 12)
- ADC2_CH2 (GPIO 13)
- ADC2_CH3 (GPIO 14)
- ADC2_CH4 (GPIO 15)
- ADC2_CH5 (GPIO 16)
- ADC2_CH6 (GPIO 17)
- ADC2_CH7 (GPIO 18)
- ADC2_CH8 (GPIO 19)
- ADC2_CH9 (GPIO 20)
The ADC input channels have a 12-bit resolution. This means that you can get analog readings ranging from 0 to 4095, in which 0 corresponds to 0 V and 4095 to 3.3 V. You can also set the resolution of your channels on the code and the ADC range.
RTC GPIOs
There is RTC GPIO support on the ESP32-S3. The GPIOs routed to the RTC low-power subsystem can be used when the ESP32 is in deep sleep. These RTC GPIOs can be used to wake up the ESP32 from deep sleep when the Ultra Low Power (ULP) coprocessor is running. The following GPIOs can be used as an external wake-up source.
- RTC_GPIO0 (GPIO0)
- RTC_GPIO1 (GPIO1)
- RTC_GPIO2 (GPIO2)
- RTC_GPIO3 (GPIO3)
- RTC_GPIO4 (GPIO4)
- RTC_GPIO5 (GPIO5)
- RTC_GPIO6 (GPIO6)
- RTC_GPIO7 (GPIO7)
- RTC_GPIO8 (GPIO8)
- RTC_GPIO9 (GPIO9)
- RTC_GPIO10 (GPIO10)
- RTC_GPIO11 (GPIO11)
- RTC_GPIO12 (GPIO12)
- RTC_GPIO13 (GPIO13)
- RTC_GPIO14 (GPIO14)
- RTC_GPIO15 (GPIO15)
- RTC_GPIO16 (GPIO16)
- RTC_GPIO17 (GPIO17)
- RTC_GPIO18 (GPIO18)
- RTC_GPIO19 (GPIO19)
- RTC_GPIO20 (GPIO20)
- RTC_GPIO21 (GPIO21)
PWM
The ESP32-S3 has an LED PWM controller with 8 PWM channels that can be configured to generate PWM signals with different properties. All pins that can act as outputs can be used as PWM pins.
To set a PWM signal, you need to define these parameters in the code:
- Signal’s frequency;
- Duty cycle;
- PWM channel (optional);
- GPIO where you want to output the signal.
I2C
When using the ESP32-S3 with the Arduino IDE, these are the ESP32 I2C default pins:
- GPIO 8 (SDA)
- GPIO 9 (SCL)
Learn more about I2C with our tutorials:
- ESP32 I2C Communication: Set Pins, Multiple Bus Interfaces and Peripherals (Arduino IDE)
- ESP32: I2C Scanner (Arduino IDE) – Finding the Address of I2C Devices
- ESP32 I2C Master and Slave (I2C Communication Between Two ESP32) – Arduino IDE
SPI
The ESP32 integrates 4 SPI peripherals: SPI0, SPI1, SPI2 (commonly referred to as HSPI), and SPI3 (commonly referred to as VSPI).
SP0 and SP1 are used internally to communicate with the built-in flash memory, and you should not use them for other tasks.
You can use HSPI and VSPI to communicate with other devices. HSPI and VSPI have independent bus signals.
| SPI | MOSI | MISO | CLK | CS |
| HSPI (SPI 2) | GPIO 11 | GPIO 13 | GPIO 12 | GPIO 10 |
| VSPI (SPI 3) | GPIO 35 | GPIO 37 | GPIO 36 | GPIO 39 |
Learn more about SPI communication protocol: ESP32 SPI Communication: Set Pins, Multiple SPI Bus Interfaces, and Peripherals (Arduino IDE).
Interrupts
All GPIOs can be configured as interrupts.
UART Pins – Serial Communication
The ESP32-S3 supports multiple UART (Universal Asynchronous Receiver-Transmitter) interfaces that allow serial communication with various devices. The ESP32 supports up to three UART interfaces: UART0, UART1, and UART2, depending on the ESP32 board model you’re using.
Like I2C and SPI, these UARTs can be mapped to any GPIO pin, although they have default pin assignments on most board models.
The following table shows the default UART0, UART1, and UART2 RX and TX pins for the ESP32-S3:
| UART Port | TX | RX | Remarks |
| UART0 | GPIO 43 | GPIO 44 | Cannot be changed |
| UART1 | GPIO 17 | GPIO 18 | Can be assigned to other GPIOs |
| UART2 | — | — | Assign any pins of your choice |
Strapping Pins
The ESP32-S3 chip has the following strapping pins:
- GPIO 0
- GPIO 3
- GPIO 45
- GPIO 46
These pins are used to put the ESP32 into bootloader or flashing mode. On most development boards with built-in USB/Serial, you don’t need to worry about the state of these pins. The board puts the pins in the right state for flashing or boot mode. However, you should avoid using these pins on your projects.
Enable (EN/RST)
The Enable (EN/RST) is the 3.3V regulator’s enable pin. It’s pulled up, so connect to GND to disable the 3.3V regulator. This means that you can use this pin connected to a pushbutton to restart your ESP32, for example.
Wrapping Up
We hope you find this reference guide for the ESP32-S3 GPIOs useful. If you have more tips about the ESP32-S3 GPIOs, please share by writing a comment below.
More ESP32 content:
Thanks for reading.
If pin GPIO 8 (SDA) , GPIO 9 (SCL) are occupied it is possible to use some other pins fo I2C?
Thanks
Renzo
Hi Sara,
Thank you very much for this short tutorial.
I have the exact questions Boris request.
Using the 16MB Flash would really be great.
For Renzo,
Try some variant of the following code to redefine I2C pins for any ESP32.
The following code can be used to redefine I2C & reads an analog signal using an I2C device, The analog signal on pin A0 of the ADS1115 is from a light sensor that detects a laser pulse at high resolution.
The ADS1115 is an I2C device with 16 bit resolution and a multiplexed 4 channel Analog to Digital Converter.
Adafruit has some excellent info on how to use and on programmable gain for the ADS1115.
Note that the 20 ADC channels on ESP32 are 12 bit.
Also the following code does not include all the initialization for the variables, or all the calls, or all the functions.
It is hoped that it will help illustrate the concepts for redefining I2C pins, etc.)
// Include the I2C library
#include <Wire.h>
// Include a library for the I2C device, for example an I2C using a 16bit ADC
#include <Adafruit_ADS1X15.h>
// Define I2C pins
#define SDA_PIN 21 // Replace with your desired SDA pin
#define SCL_PIN 22 // Replace with your desired SCL pin
Adafruit_ADS1115 ads; // Create an instance of the ADS1115 ADC
const int analogInputPin = 0; // Initialize the A0 pin on ADS1115 device
// Initialize global variables
const int numSamplesForBaseline = 100;
const int numSamplesPerPulse = 10;
unsigned long previousMicros = 0;
unsigned long sampleIntervalMicros = 500;
int baselineThreshold = 0;
int analogSum = 0;
int pulseCount = 0;
int averageAmplitude = 0;
void setup() {
Serial.begin(115200);
Wire.begin(SDA_PIN, SCL_PIN); // Initialize I2C w specified SDA & SCL pins
ads.begin();
// Calculate baseline threshold during initialization
calculateBaselineThreshold();
// Insert other code for setup
}
void loop() {
// Read and process analog signal
processAnalogSignal(currentMicros);
// Main loop code Example: Print results every 10 seconds
if (currentMicros – previousMicros >= 10000000) {
printResultsToSerial();
sendResultsToThingSpeak();
previousMicros = currentMicros;
}
}
void processAnalogSignal(unsigned long currentMicros) {
int rawAnalogValue = ads.readADC_SingleEnded(analogInputPin);
baselineThreshold = (baselineThreshold + rawAnalogValue) / 2;
if (rawAnalogValue > baselineThreshold) {
if (currentMicros – previousMicros >= sampleIntervalMicros) {
for (int i = 0; i < numSamplesPerPulse; i++) {
rawAnalogValue = ads.readADC_SingleEnded(analogInputPin);
analogSum += rawAnalogValue;
}
averageAmplitude = analogSum / numSamplesPerPulse;
analogSum = 0;
pulseCount++;
previousMicros = currentMicros;
}
}
}
void printResultsToSerial() {
Serial.println(“Average Amplitude: ” + String(averageAmplitude));
Serial.println(“Pulse Count: ” + String(pulseCount));
}
Best regards,
Joe
Hi Renzo,
Random Nerds has a great I2C tutorial at
https://randomnerdtutorials.com/esp32-i2c-communication-arduino-ide/
It shows how to redefine ESP32 pins for I2C.
Best regards,
Joe
Hello guys!!
I got the exact same board. I would really appreciate a tutorial on how to use the full 16mb flash memory.
I tried a lot of things but I never could use more than 3.5mb something no matter what settings I selected in the Arduino IDE.
Have a great day!!
Boris
I have the same problem. Tried about everything I could find on the Web to no avail. Would really like a tutorial on that.
Thanks in advance.
Frank
Should MOSI of HSPI (SPI 2) not be GPIO11 instead of GPIO35?
Yes. You’re right.
It’s fixed now.
Regards,
Sara
Why don’t you guys make projects using ESP-IDF? Your step by step guide will be really helpful for others.
Many questions come up to mind, I guess most of your projects should be reviewed using this board, especially the ones about memery management and usage of sd cards. Thank you for this first coverage of this board.
Does anyone has an idea about how to achieve debugging with this board because it has this dedicated usbc port for this purpose.
I have been using this exact DevKit, a true Espressif version, not one of the countless variations, for over a year and have discovered via much frustration that some of the pin-outs you list are not correct or should be avoided, at least with MicroPython firmware. You should not/cannot use TX0/RX0, HSPI is GPIO9-11, GPIO48 is the RGB led, and GPIO35-37 can be used on the N8 variant (no PSRAM) but not on the N8R8 variant (with PSRAM).
Hi.
Thanks for your feedback.
I’ll that a look into that.
Regards,
Sara