Espressif ESP32-S2-DevKitM-1
Compact official ESP32-S2 board with secure boot - great for secure IoT prototyping and embedded dev.
Espressif ESP32-S2-DevKitM-1 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 | safe | spi · pwm | Default SPI MISO; FSPIQ; SPIDQS |
| 34 | 36 | IO36SCK | safe | spi · pwm | Default SPI SCK; FSPICLK; SPIIO7 |
| 35 | 35 | IO35MOSI | safe | spi · pwm | Default SPI MOSI; FSPID; SPIIO6 |
| 36 | 34 | IO34SS | safe | spi · pwm | Default SPI SS; FSPICS0; SPIIO5 |
| 37 | 33 | IO33 | safe | pwm | FSPIHD; SPIIO4 |
| 38 | 26 | IO26 | safe | 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
20 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
15 pins · 10 things to knowIO0 Bootstrapping pin; selects boot mode (SPI Boot vs UART Download). Strapping
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.
IO9IO10IO11IO12IO13IO14 General-purpose SPI2 (FSPI) IO MUX pins Other
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.
- IO9General-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD)
- IO10General-purpose SPI2 (FSPI) IO MUX pin - chip select (FSPICS0)
- IO11General-purpose SPI2 (FSPI) IO MUX pin - data in (FSPID)
- IO12General-purpose SPI2 (FSPI) IO MUX pin - clock (FSPICLK)
- IO13General-purpose SPI2 (FSPI) IO MUX pin - data out (FSPIQ)
- IO14General-purpose SPI2 (FSPI) IO MUX pin - write-protect/data line (FSPIWP)
IO15 32.768 kHz RTC crystal oscillator positive input (XTAL_32K_P); also functions as GPIO15 (U0RTS, ADC2_CH4). Other
If an external 32 kHz crystal is used for RTC, this pin is dedicated to the crystal and cannot be used as GPIO.
IO16 32.768 kHz RTC crystal negative input (XTAL_32K_N); also GPIO16 (U0CTS, ADC2_CH5). Other
If using an external 32 kHz crystal, this pin is connected to the crystal and should not be used as general I/O.
IO46 Bootstrapping pin; controls printing of ROM boot messages; internal pull-down (logic 0 by default); input-only GPIO. Strapping
If pulled high during boot, it can disable bootloader log output (depending on eFuse settings). Cannot drive output (input-only pin).
IO45 Bootstrapping pin; selects flash supply voltage (VDD_SPI) (0 = 3.3 V, 1 = 1.8 V). Strapping
Must be set correctly at boot (usually low for 3.3 V); improper level can cause boot failure or flash malfunction.
IO42 JTAG test mode select pin (MTMS); also GPIO42. JTAG
JTAG TMS pin; should not be repurposed if JTAG debugging or programming via JTAG is required.
IO41 JTAG test data-in pin (MTDI); also GPIO41, supports CLK_OUT1. JTAG
Part of JTAG interface (TDI); avoid using as GPIO to retain ability for JTAG debug.
IO40 JTAG test data-out pin (MTDO); also GPIO40, supports CLK_OUT2. JTAG
Part of JTAG interface (TDO); should be avoided as GPIO if JTAG debugging is needed.
IO39 JTAG test clock pin (MTCK); also usable as GPIO39 or as a clock output (CLK_OUT3). JTAG
Used for JTAG debugging interface; using this pin for other purposes will disable JTAG clock input.
Only if you know the tricks
2 pins · 2 things to knowIO20 USB OTG D+ line (full-speed USB data +); also serves as GPIO20/RTC_GPIO20 and ADC2 channel 9. USB
Dedicated to USB interface; repurposing as GPIO may disrupt USB connectivity.
IO19 USB OTG D- line (full-speed USB data -); also available as GPIO19/RTC_GPIO19 and ADC2 channel 8. USB
Used for USB communication; using this pin as general GPIO can interfere with USB functionality.
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 16 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 minutesBoard: 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
// 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);
}[env:esp32-s2-devkitm-1]
platform = espressif32
board = esp32-s2-saola-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32-s2-saola-1 - or type it after board =.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_outesp32-s2-saola-1 (same ids as PlatformIO).esptool.py --chip esp32s2 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32-S2 · 54 × 25.4 mm · vs other ESP32 chips →Dimensions
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 pricesResources
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