Adafruit QT Py ESP32-S2
Tiny ESP32-S2 board with STEMMA QT and USB-C - ideal for compact, plug-and-play IoT applications.
Adafruit QT Py ESP32-S2 Pinout
16 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 5 | A6TXT5PWM | uart | adc · touch · uart | |
| 2 | 6 | SCLA5T6PWM | safe | adc · touch · i2c | |
| 3 | 7 | SDAA4T7PWM | safe | adc · touch · i2c | |
| 4 | 8 | A3T8PWM | safe | adc · touch | |
| 5 | 9 | A2T9PWM | strapping | adc · touch | |
| 6 | 16 | A7RXPWM | strapping | adc · uart | |
| 7 | 17 | A1DAC1PWM | safe | adc · dac | |
| 8 | 18 | A0DAC2PWM | safe | adc · dac | |
| 9 | 35 | MOSIPWM | safe | spi | |
| 10 | 36 | SCKPWM | safe | spi | |
| 11 | 37 | MISOPWM | safe | spi | |
| 12 | 38 | NEOPIXEL_POWERPWM | safe | - | |
| 13 | 39 | PIN_NEOPIXELPWM | strapping | - | |
| 14 | 40 | SCL1PWM | strapping | - | |
| 15 | 41 | SDA1PWM | strapping | - | |
| 16 | 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
6 pins · 6 things to knowA2GPIO9 General-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD) 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.
A7GPIO16 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.
PIN_NEOPIXELGPIO39 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.
SCL1GPIO40 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.
SDA1GPIO41 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.
SSGPIO42 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.
The Adafruit QT Py ESP32-S2 pinout brings out 16 GPIO pins at a 2.54 mm pitch - every one of them usable in your project.
For peripherals, I²C is mapped to SDA on GPIO7 and SCL on GPIO6; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO5 and GPIO16 cover serial logging and flashing.
On the analog side there are 8 ADC-capable pins for sensors and battery monitoring, 5 capacitive-touch inputs and 2 true DAC outputs.
If you want zero surprises, A6, SCL, SDA, A3 and 6 more are free of any such role - the safest first picks. 6 of the exposed pins carry boot-time or system duties on the ESP32-S2 (A2, A7, PIN_NEOPIXEL and 3 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32S2 Dev Module USB CDC On Boot: Enabled Flash Size: 4MB (32Mb) Flash Mode: DIO PSRAM: QSPI PSRAM Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO6 - wire an LED and resistor to it
void setup() {
pinMode(6, OUTPUT);
}
void loop() {
digitalWrite(6, HIGH); delay(500);
digitalWrite(6, LOW); delay(500);
}[env:adafruit_qtpy_esp32s2]
platform = espressif32
board = esp32-s2-saola-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMesp32-s2-saola-1 - or type it after board =.esp32:
board: esp32-s2-saola-1
variant: esp32s2
framework:
type: esp-idf
psram:
mode: quad
speed: 80MHz
# blink - GPIO6
output:
- platform: gpio
pin: 6
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 · 21.8 × 17.9 mm · vs other ESP32 chips →Dimensions
About this board
At 21.8 × 17.9 mm it's the smallest ESP32-S2 board we've measured.
At its core is the ESP32-S2 - a single-core Xtensa with native USB-OTG and no Bluetooth.
Expect to pay about $12.50 - less than the ~$20 most ESP32-S2 boards go for.
The small footprint costs pins: 16 GPIO are broken out, versus 26 or so on a full-size board.
Onboard you'll find 2MB (QSPI) PSRAM, a STEMMA QT connector, an addressable RGB LED (GPIO39) and Reset/Boot buttons.
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S2 boards.
Where to buy
prices are typical street pricesResources
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