Adafruit QT Py ESP32
Ultra-compact ESP32 board with STEMMA QT - perfect for plug-and-play sensor projects and tight-space builds.
Pinout
17 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | BUTTON | strapping | - | |
| 2 | 1 | WIRE1_PIN_DEFINEDPWM | uart | - | |
| 3 | 4 | SDAA4T0PWM | strapping | adc · touch · i2c | |
| 4 | 5 | PIN_NEOPIXELPWM | strapping | - | |
| 5 | 7 | RXRX1A7PWM | strapping | adc · uart | |
| 6 | 8 | NEOPIXEL_POWERPWM | strapping | - | |
| 7 | 12 | MISOA9T5PWM | strapping | adc · touch · spi | |
| 8 | 13 | MOSIA10T4PWM | strapping | adc · touch · spi | |
| 9 | 14 | SCKA8T6PWM | strapping | adc · touch · spi | |
| 10 | 15 | A3T3PWM | strapping | adc · touch | |
| 11 | 19 | SCL1PWM | safe | - | |
| 12 | 22 | SDA1PWM | safe | - | |
| 13 | 25 | A1DAC1PWM | safe | adc · dac | |
| 14 | 26 | A0DAC2PWM | safe | adc · dac | |
| 15 | 27 | SSA2T7PWM | safe | adc · touch · spi | |
| 16 | 32 | TXTX1A6T9PWM | uart | adc · touch · uart | |
| 17 | 33 | SCLA5T8PWM | safe | adc · touch · i2c |
Start with these
7 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 |
|---|---|---|---|
| BUTTON | GPIO0 | Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode. | Strapping |
| SDA | GPIO4 | Sampled at reset for boot config; should not be driven at boot (affects boot mode timing). | Strapping |
| PIN_NEOPIXEL | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | Strapping |
| MISO | MTDI (GPIO12) | Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used. | Strapping |
| MOSI | MTCK (GPIO13) | Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed. | Other |
| SCK | MTMS (GPIO14) | Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot. | Other |
| A3 | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| WIRE1_PIN_DEFINED | U0TXD (GPIO1) | Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console. | USB |
| RX | GPIO7 (Flash SD0) | Used for internal flash/PSRAM data; not available for general GPIO. | Flash |
| NEOPIXEL_POWER | GPIO8 (Flash SD1) | Used for internal flash/PSRAM data; not available for general GPIO. | Flash |
Pinout notes All 17 pins on the Adafruit QT Py ESP32 are usable GPIO, spaced at the standard 2.54 mm pitch. Peripheral wiring is straightforward: I²C is mapped to SDA on…
All 17 pins on the Adafruit QT Py ESP32 are usable GPIO, spaced at the standard 2.54 mm pitch.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO4 and SCL on GPIO33; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO32 and GPIO7 cover serial logging and flashing.
Beyond plain digital I/O you get 11 ADC-capable pins for sensors and battery monitoring, 8 capacitive-touch inputs and 2 true DAC outputs.
7 of the exposed pins carry boot-time or system duties on the ESP32 (BUTTON, SDA, PIN_NEOPIXEL and 4 more) - check the guidance above before wiring anything to them. SCL1, SDA1, A1, A0 and 3 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: Adafruit Qtpy Esp32 Pico
Flash Size: 8MB · DIO
Upload Speed: 921600
// blink
pinMode(19, OUTPUT);
digitalWrite(19, LOW); // on (often inverted)[env:adafruit_qtpy_esp32_pico]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32dev
variant: adafruit_qtpy_esp32
framework:
type: esp-idf
# blink - GPIO19
output:
- platform: gpio
pin: 19
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binSpecifications
ESP32 · 22 × 17.9 mmAbout this board
At 22 × 17.9 mm it's among the smallest boards in the whole ESP32 family.
Inside sits the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
At $14.95 it's cheaper than most ESP32 boards, which usually run around $20.
The small footprint costs pins: 17 GPIO are broken out, versus 24 or so on a full-size board.
Around the module: 2MB (QSPI) PSRAM, a STEMMA QT connector, an addressable RGB LED (GPIO5) and Reset/Boot buttons.
Where to buy
prices are typical street pricesResources
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