Adafruit ItsyBitsy ESP32
Small ESP32 board in ItsyBitsy format - ideal for low-power wireless projects in compact enclosures.
Adafruit ItsyBitsy ESP32 Pinout
21 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | PIN_NEOPIXEL | strapping | - | |
| 2 | 2 | NEOPIXEL_POWERPWM | strapping | - | |
| 3 | 4 | A2T0PWM | safe | adc · touch | |
| 4 | 8 | RXPWM | strapping | uart | |
| 5 | 12 | T5PWM | strapping | touch | |
| 6 | 13 | LED_BUILTINT4PWM | strapping | touch | |
| 7 | 14 | T6PWM | strapping | touch | |
| 8 | 15 | SDAT3PWM | strapping | touch · i2c | |
| 9 | 19 | SCKPWM | safe | spi | |
| 10 | 20 | TXPWM | uart | uart | |
| 11 | 21 | MOSIPWM | safe | spi | |
| 12 | 22 | MISOPWM | safe | spi | |
| 13 | 25 | A0DAC1PWM | safe | adc · dac | |
| 14 | 26 | A1DAC2PWM | safe | adc · dac | |
| 15 | 27 | SCLT7PWM | safe | touch · i2c | |
| 16 | 32 | SST9PWM | safe | touch · spi | |
| 17 | 33 | T8PWM | safe | touch | |
| 18 | 35 | BUTTON | strapping | - | |
| 19 | 36 | A5 | strapping | adc | |
| 20 | 37 | A4 | strapping | adc | |
| 21 | 38 | A3 | strapping | adc |
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
10 pins · 8 things to knowPIN_NEOPIXELGPIO0 Bootstrapping pin (enter bootloader when low); internal pull-up. Strapping
Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.
NEOPIXEL_POWERGPIO2 Bootstrapping pin (must be low or floating at reset); internal pull-down. Strapping
If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.
T5GPIO12 Bootstrapping pin; JTAG TDI; sets flash voltage (VDD_SDIO); also HSPIQ (flash data line). Strapping
Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used.
LED_BUILTINGPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
T6GPIO14 JTAG mode select pin (TMS); also HSPI CLK and PWM-capable GPIO. JTAG
Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.
SDAGPIO15 Bootstrapping pin; JTAG TDO; controls UART0 boot log output; also HSPICS0 (secondary SPI CS). Strapping
Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.
BUTTONGPIO35A4GPIO37A3GPIO38 Input-only GPIOs with ADC1 channels - no output driver Other
Cannot be used as output; only suitable for input.
- BUTTONInput-only GPIO (no output driver); ADC1 channel 7.
- A4Input-only GPIO (no output); ADC1 channel 1.
- A3Input-only GPIO (no output); ADC1 channel 2.
A5GPIO36 Input-only GPIO (no output); ADC1 channel 0, Hall sensor VP. Other
Cannot be used as output; only suitable for input (e.g., analog read).
Only if you know the tricks
1 pins · 1 thing to knowRXGPIO8 Connected to SPI flash data 1 (SD1). Flash
Used for internal flash/PSRAM data; not available for general GPIO.
All 21 pins on the Adafruit ItsyBitsy ESP32 are usable GPIO, spaced at the standard 2.54 mm pitch.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO15 and SCL on GPIO27; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO20 and GPIO8 cover serial logging and flashing.
Beyond plain digital I/O you get 6 ADC-capable pins for sensors and battery monitoring, 8 capacitive-touch inputs and 2 true DAC outputs.
10 of the exposed pins carry boot-time or system duties on the ESP32 (PIN_NEOPIXEL, NEOPIXEL_POWER, T5 and 7 more) - check the guidance above before wiring anything to them. A2, SCK, TX, MOSI and 6 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: ESP32 Wrover Module Flash Size: 8MB (64Mb) Flash Mode: DIO PSRAM: QSPI PSRAM Partition Scheme: 8M with spiffs (3MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO4 - wire an LED and resistor to it
void setup() {
pinMode(4, OUTPUT);
}
void loop() {
digitalWrite(4, HIGH); delay(500);
digitalWrite(4, LOW); delay(500);
}[env:adafruit_itsybitsy_esp32]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMesp32dev - or type it after board =.esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
psram:
mode: quad
speed: 80MHz
# blink - GPIO4
output:
- platform: gpio
pin: 4
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32dev (same ids as PlatformIO).esptool.py --chip esp32 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32 · 36 × 17.6 mm · vs other ESP32 chips →Dimensions
About this board
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.
Around the module: 2MB (QSPI) PSRAM, a STEMMA QT connector, status LEDs (Red (D13)) and Reset/User buttons.
Where to buy
prices are typical street pricesResources
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