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Espressif ESP32-S2-DevKitM-1
Compact official ESP32-S2 board with secure boot - great for secure IoT prototyping and embedded dev.
54 × 25.4 mm
ESP32-S2
MCU
240MHz
clock
4MB
flash
320KB
SRAM
37· 20 ADC
GPIO
Wi-Fi
radio
Pinout
42 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | - | 3V33.3V | power | - | 3.3V regulated output |
| 2 | 0 | IO0 | strapping | pwm | BOOT button; RTC |
| 3 | 1 | IO1A0T1 | safe | adc · touch · pwm | ADC1_CH0; Touch1; RTC |
| 4 | 2 | IO2A1T2 | safe | adc · touch · pwm | ADC1_CH1; Touch2; RTC |
| 5 | 3 | IO3A2T3 | safe | adc · touch · pwm | ADC1_CH2; Touch3; RTC |
| 6 | 4 | IO4A3T4 | safe | adc · touch · pwm | ADC1_CH3; Touch4; RTC |
| 7 | 5 | IO5A4T5 | safe | adc · touch · pwm | ADC1_CH4; Touch5; RTC |
| 8 | 6 | IO6A5T6 | safe | adc · touch · pwm | ADC1_CH5; Touch6; RTC |
| 9 | 7 | IO7A6T7 | safe | adc · touch · pwm | ADC1_CH6; Touch7; RTC |
| 10 | 8 | IO8A7T8SDA | safe | adc · touch · i2c · pwm | Default I2C SDA; ADC1_CH7; Touch8 |
| 11 | 9 | IO9A8T9SCL | strapping | adc · touch · i2c · pwm | Default I2C SCL; ADC1_CH8; Touch9; FSPIHD |
| 12 | 10 | IO10A9T10 | strapping | adc · touch · pwm | ADC1_CH9; Touch10; FSPICS0 |
| 13 | 11 | IO11A10T11 | strapping | adc · touch · pwm | ADC2_CH0; Touch11; FSPID |
| 14 | 12 | IO12A11T12 | strapping | adc · touch · pwm | ADC2_CH1; Touch12; FSPICLK |
| 15 | 13 | IO13A12T13 | strapping | adc · touch · pwm | ADC2_CH2; Touch13; FSPIQ |
| 16 | 14 | IO14A13T14 | strapping | adc · touch · pwm | ADC2_CH3; Touch14; FSPIWP |
| 17 | 15 | IO15A14 | strapping | adc · pwm | ADC2_CH4; U0RTS; XTAL_32K_P |
| 18 | 16 | IO16A15 | strapping | adc · pwm | ADC2_CH5; U0CTS; XTAL_32K_N |
| 19 | 17 | IO17A16DAC1 | safe | adc · dac · pwm | DAC1; ADC2_CH6; U1TXD |
| 20 | - | 5V | power | - | 5V input (from USB) / output |
| 21 | - | GND | ground | - | Ground |
| 22 | - | GND | ground | - | Ground |
| 23 | - | RSTEN | control | - | Chip reset (active low) |
| 24 | 46 | IO46 | strapping | - | Input-only GPIO |
| 25 | 45 | IO45 | strapping | pwm | General-purpose GPIO |
| 26 | 44 | IO44RX | uart | uart · pwm | UART0 RX (default Serial); CLK_OUT2 |
| 27 | 43 | IO43TX | uart | uart · pwm | UART0 TX (default Serial); CLK_OUT1 |
| 28 | 42 | IO42 | strapping | pwm | JTAG MTMS |
| 29 | 41 | IO41 | strapping | pwm | JTAG MTDI; CLK_OUT1 |
| 30 | 40 | IO40 | strapping | pwm | JTAG MTDO; CLK_OUT2 |
| 31 | 39 | IO39 | strapping | pwm | JTAG MTCK; CLK_OUT3 |
| 32 | 38 | IO38 | safe | pwm | FSPIWP |
| 33 | 37 | IO37MISO | strapping | spi · pwm | Default SPI MISO; FSPIQ; SPIDQS |
| 34 | 36 | IO36SCK | strapping | spi · pwm | Default SPI SCK; FSPICLK; SPIIO7 |
| 35 | 35 | IO35MOSI | strapping | spi · pwm | Default SPI MOSI; FSPID; SPIIO6 |
| 36 | 34 | IO34SS | strapping | spi · pwm | Default SPI SS; FSPICS0; SPIIO5 |
| 37 | 33 | IO33 | strapping | pwm | FSPIHD; SPIIO4 |
| 38 | 26 | IO26 | strapping | pwm | General-purpose GPIO |
| 39 | 21 | IO21 | safe | pwm | General-purpose GPIO; RTC |
| 40 | 20 | IO20A19 | uart | adc · pwm | Native USB D+; ADC2_CH9; U1CTS; RTC |
| 41 | 19 | IO19A18 | uart | adc · pwm | Native USB D-; ADC2_CH8; U1RTS; RTC |
| 42 | 18 | IO18A17DAC2 | safe | adc · dac · pwm | Onboard RGB LED; DAC2; ADC2_CH7; U1RXD |
Start with these
14 pins with no boot or system involvementIO1A0IO2A1IO3A2IO4A3IO5A4IO6A5IO7A6IO8A7IO17A16IO44RXIO43TXIO38IO21IO18A17
Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| IO0 | GPIO0 | Must be pulled high for normal boot; pulling low at reset enters bootloader (download mode). Also serves as SPI flash data-in (SPID) line when using external flash memory. | Strapping |
| IO9 | FSPIHD | IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI. | Other |
| IO10 | FSPICS0 | IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI. | Other |
| IO11 | FSPID | IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI. | Other |
| IO12 | FSPICLK | IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI. | Other |
| IO13 | FSPIQ | IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI. | Other |
| IO14 | FSPIWP | IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI. | Other |
| IO15 | XTAL_32K_P | If an external 32 kHz crystal is used for RTC, this pin is dedicated to the crystal and cannot be used as GPIO. | Other |
| IO16 | XTAL_32K_N | If using an external 32 kHz crystal, this pin is connected to the crystal and should not be used as general I/O. | Other |
| IO46 | GPIO46 | If pulled high during boot, it can disable bootloader log output (depending on eFuse settings). Cannot drive output (input-only pin). | Strapping |
| IO45 | GPIO45 | Must be set correctly at boot (usually low for 3.3 V); improper level can cause boot failure or flash malfunction. | Strapping |
| IO42 | MTMS | JTAG TMS pin; should not be repurposed if JTAG debugging or programming via JTAG is required. | Other |
| IO41 | MTDI | Part of JTAG interface (TDI); avoid using as GPIO to retain ability for JTAG debug. | Other |
| IO40 | MTDO | Part of JTAG interface (TDO); should be avoided as GPIO if JTAG debugging is needed. | Other |
| IO39 | MTCK | Used for JTAG debugging interface; using this pin for other purposes will disable JTAG clock input. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| IO37 | SPIDQS (GPIO37) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode, and can be GPIO pins if the chip is not connected to flash or PSRAM in 8-line SPI mode". Quad-SPI parts leave it free. | Flash |
| IO36 | SPIIO7 (GPIO36) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode, and can be GPIO pins if the chip is not connected to flash or PSRAM in 8-line SPI mode". Quad-SPI parts leave it free. | Flash |
| IO35 | SPIIO6 (GPIO35) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode, and can be GPIO pins if the chip is not connected to flash or PSRAM in 8-line SPI mode". Quad-SPI parts leave it free. | Flash |
| IO34 | SPIIO5 (GPIO34) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode, and can be GPIO pins if the chip is not connected to flash or PSRAM in 8-line SPI mode". Quad-SPI parts leave it free. | Flash |
| IO33 | SPIIO4 (GPIO33) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode, and can be GPIO pins if the chip is not connected to flash or PSRAM in 8-line SPI mode". Quad-SPI parts leave it free. | Flash |
| IO26 | SPICS1 | Part of the SPI0/1 bus that runs the in-package flash and PSRAM, listed by the datasheet as "already allocated or not recommended for use". Modules keep these lines internal, so the pin is not available as GPIO. | Flash |
| IO20 | USB_D+ | Dedicated to USB interface; repurposing as GPIO may disrupt USB connectivity. | USB |
| IO19 | USB_D- | Used for USB communication; using this pin as general GPIO can interfere with USB functionality. | USB |
These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.
Pinout notes Across 42 pins (2.54 mm pitch), the Espressif ESP32-S2-DevKitM-1 exposes 37 GPIO plus 3V3, 5V and GND for power. For peripherals, I²C is mapped to SDA on GPIO8…
Across 42 pins (2.54 mm pitch), the Espressif ESP32-S2-DevKitM-1 exposes 37 GPIO plus 3V3, 5V and GND for power.
For peripherals, I²C is mapped to SDA on GPIO8 and SCL on GPIO9; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO43 and GPIO44 cover serial logging and flashing.
On the analog side there are 20 ADC-capable pins for sensors and battery monitoring, PWM on 36 pins, 14 capacitive-touch inputs and 2 true DAC outputs.
If you want zero surprises, IO1, IO2, IO3, IO4 and 10 more are free of any such role - the safest first picks. 15 of the exposed pins carry boot-time or system duties on the ESP32-S2 (IO0, IO9, IO10 and 12 more).
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Install your USB-serial driver (CH340 / CP210x) if no port appears. Not detected? Hold BOOT while plugging in.
2
Match & flash
Set the Tools options shown, then click Upload.
3
Verify it runs
GPIO1 toggles - wire an LED and resistor to it, or change the pin to your board's own LED.
Set these in Tools · leave everything else at default
Arduino IDE 2.x - Tools Copy
Board: "ESP32S2 Dev Module"▸
Flash Size: "4MB (32Mb)"▸
Flash Mode: "DIO"▸
Partition Scheme: "Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS)" (default)▸
Upload Speed: "921600"▸
▸ every other Tools option - leave at default
Board: ESP32S2 Dev Module Flash Size: 4MB (32Mb) Flash Mode: DIO Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32S2 Dev Module
// toggle GPIO1 - wire an LED and resistor to it
void setup() {
pinMode(1, OUTPUT);
}
void loop() {
digitalWrite(1, HIGH); delay(500);
digitalWrite(1, LOW); delay(500);
}board to selectesp32-s2-saola-1⧉ copy
[env:esp32-s2-devkitm-1]
platform = espressif32
board = esp32-s2-saola-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600Find it: PlatformIO Home ▸ Boards, search
esp32-s2-saola-1 - or type it after board =.board to selectesp32-s2-saola-1⧉ copy
esp32:
board: esp32-s2-saola-1
variant: esp32s2
framework:
type: esp-idf
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outFind it: search ESPHome's board list for
esp32-s2-saola-1 (same ids as PlatformIO).esptool doesn't pick board settings - a prebuilt .bin already has them baked in. This is just the raw flash command.
esptool.py --chip esp32s2 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Build details: sketch space 2097152 B · data 327680 B · DIO
Specifications
ESP32-S2 · 54 × 25.4 mm · vs other ESP32 chips →Compute
MCU
ESP32-S2
Clock
240 MHz
SRAM · Flash
320 KB · 4MB
Radio
Wi-Fi
802.11 b/g/n 2.4 GHz
Bluetooth
-
Antenna
PCB
I/O
GPIO · ADC
37 · 20
UART · I²C · SPI
2 · 2 · 2
PWM
8 channels
Power
USB
Micro-USB
Serial
CP2102N
Boot address
0x1000
Electrical
Input
5V USB
Consumption
-
Regulator
SGM2212
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
2 MB · 320 KB
54 × 25.4 mm · pin pitch 2.54 mm
The Espressif ESP32-S2-DevKitM-1 uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with DIO boot mode. The maximum sketch size is 2 MB with 320 KB available for data.
About this board
At its core is the ESP32-S2 - a single-core Xtensa with native USB-OTG and no Bluetooth.
Expect to pay about $8.00 - less than the ~$20 most ESP32-S2 boards go for.
37 GPIO are broken out - more than most ESP32-S2 boards, so the pin budget is rarely the constraint.
Onboard you'll find an addressable RGB LED (GPIO18) and Boot/Reset buttons.
Where to buy
prices are typical street pricesAs an Amazon Associate, ESPboards earns from qualifying purchases.
Resources
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