Adafruit Feather ESP32-S2
ESP32-S2 Feather board with USB-C and STEMMA QT - ideal for secure, battery-powered IoT projects.
Pinout
25 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | NEOPIXEL_NUMPWM | safe | - | |
| 2 | 3 | SDAPWM | safe | i2c | |
| 3 | 4 | SCLPWM | safe | i2c | |
| 4 | 5 | T5PWM | safe | touch | |
| 5 | 6 | T6PWM | safe | touch | |
| 6 | 7 | I2C_POWERPIN_I2C_POWERPWM | safe | - | |
| 7 | 8 | A5T8PWM | safe | adc · touch | |
| 8 | 9 | T9PWM | strapping | touch | |
| 9 | 10 | T10PWM | strapping | touch | |
| 10 | 11 | T11PWM | strapping | touch | |
| 11 | 12 | T12PWM | strapping | touch | |
| 12 | 13 | LED_BUILTINT13PWM | strapping | touch | |
| 13 | 14 | A4T14PWM | strapping | adc · touch | |
| 14 | 15 | A3PWM | strapping | adc | |
| 15 | 16 | A2PWM | strapping | adc | |
| 16 | 17 | A1DAC1PWM | safe | adc · dac | |
| 17 | 18 | A0DAC2PWM | safe | adc · dac | |
| 18 | 21 | NEOPIXEL_POWERPWM | safe | - | |
| 19 | 33 | PIN_NEOPIXELPWM | strapping | - | |
| 20 | 35 | MOSIPWM | strapping | spi | |
| 21 | 36 | SCKPWM | strapping | spi | |
| 22 | 37 | MISOPWM | strapping | spi | |
| 23 | 38 | RXPWM | strapping | uart | |
| 24 | 39 | TXPWM | strapping | uart | |
| 25 | 42 | SSPWM | strapping | spi |
Start with these
10 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
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| A3 | 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 |
| A2 | 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 |
| TX | MTCK | Used for JTAG debugging interface; using this pin for other purposes will disable JTAG clock input. | Other |
| SS | MTMS | JTAG TMS pin; should not be repurposed if JTAG debugging or programming via JTAG is required. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| T9 | FSPIHD | Typically used as flash/PSRAM IO line in certain configurations; avoid using as GPIO if flash or PSRAM is present. | Flash |
| T10 | FSPICS0 | Often used as flash chip select in some designs; not available for GPIO when controlling flash. | Flash |
| T11 | FSPID | Used for flash data transfer in certain configurations; should be avoided for general use if flash is connected. | Flash |
| T12 | FSPICLK | Used as flash clock line in some boards; not free for GPIO if driving flash. | Flash |
| LED_BUILTIN | FSPIQ | Used for flash data output in certain configurations; avoid using as GPIO if connected to flash. | Flash |
| A4 | FSPIWP | Used as flash write-protect/data line on some modules; not recommended for other usage. | Flash |
| PIN_NEOPIXEL | SPIHD | Connected to SPI flash (hold/data line); not available for general-purpose use. | Flash |
| MOSI | FSPID | Used by internal flash/PSRAM on some ESP32-S2 variants; avoid using as GPIO to prevent conflicts. | Flash |
| SCK | FSPICLK | May be connected to internal flash or used for high-speed SPI; not intended for general GPIO use. | Flash |
| MISO | FSPIQ | Used for internal flash/PSRAM data in some models; should not be repurposed for GPIO. | Flash |
| RX | FSPIWP | Reserved for flash/PSRAM in ESP32-S2 modules with internal memory; not recommended for general I/O. | Flash |
Pinout notes All 25 pins on the Adafruit Feather ESP32-S2 are usable GPIO, spaced at the standard 2.54 mm pitch. Peripheral wiring is straightforward: I²C is mapped to SDA…
All 25 pins on the Adafruit Feather ESP32-S2 are usable GPIO, spaced at the standard 2.54 mm pitch.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO3 and SCL on GPIO4; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO39 and GPIO38 cover serial logging and flashing.
Beyond plain digital I/O you get 6 ADC-capable pins for sensors and battery monitoring, 9 capacitive-touch inputs and 2 true DAC outputs.
4 of the exposed pins carry boot-time or system duties on the ESP32-S2 (A3, A2, TX and 1 more) - check the guidance above before wiring anything to them. NEOPIXEL_NUM, SDA, SCL, T5 and 6 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: Adafruit Feather Esp32s2
USB CDC On Boot: Enabled
Flash Size: 4MB · DIO
Upload Speed: 921600
// blink
pinMode(1, OUTPUT);
digitalWrite(1, LOW); // on (often inverted)[env:adafruit_feather_esp32s2]
platform = espressif32
board = esp32-s2-saola-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32-s2-saola-1
variant: adafruit_feather_esp32s2
framework:
type: esp-idf
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32s2 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binSpecifications
ESP32-S2 · 52.4 × 22.8 mmAbout this board
Inside sits the ESP32-S2 - a single-core Xtensa with native USB-OTG and no Bluetooth.
The $17.50 price tag is typical for an ESP32-S2 board.
Around the module: 2MB (QSPI) PSRAM, a STEMMA QT connector, an addressable RGB LED (GPIO33), a battery fuel gauge (MAX17048), battery charging (MCP73831) via JST-PH 2.0, status LEDs (On, Charge, User (D13)) and Reset/DFU (BOOT0) buttons.
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S2 boards.
- Also sold in a u.FL external-antenna variant
- Early units shipped with an LC709203F fuel gauge instead of the MAX17048
Where to buy
prices are typical street pricesResources
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