Microduino-CoreESP32
Stackable ESP32 board in Microduino form - perfect for modular electronics projects and classroom use.
Microduino-CoreESP32 Pinout
33 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | T1 | strapping | touch | |
| 2 | 1 | TXWIRE1_PIN_DEFINEDD1PWM | uart | uart | |
| 3 | 2 | T2PWM | strapping | touch | |
| 4 | 3 | RXD0PWM | uart | uart | |
| 5 | 4 | A3D17T0PWM | safe | adc · touch | |
| 6 | 5 | SSD10PWM | strapping | spi | |
| 7 | 12 | MTDISDA1A0D14T5PWM | strapping | adc · touch | |
| 8 | 13 | MTCKSCL1A1D15T4PWM | strapping | adc · touch | |
| 9 | 14 | MTMSA13T6PWM | strapping | adc · touch | |
| 10 | 15 | MTDOA2D16T3PWM | strapping | adc · touch | |
| 11 | 16 | D2PWM | safe | - | |
| 12 | 17 | D3PWM | safe | - | |
| 13 | 18 | SCKD13PWM | safe | spi | |
| 14 | 19 | MISOD12PWM | safe | spi | |
| 15 | 21 | D19PWM | safe | - | |
| 16 | 22 | D18PWM | safe | - | |
| 17 | 23 | MOSID11PWM | safe | spi | |
| 18 | 25 | A10DAC1PWM | safe | adc · dac | |
| 19 | 26 | A11DAC2PWM | safe | adc · dac | |
| 20 | 27 | A12T7PWM | safe | adc · touch | |
| 21 | 32 | A8T9PWM | safe | adc · touch | |
| 22 | 33 | A9T8PWM | safe | adc · touch | |
| 23 | 37 | A7D21 | strapping | adc | |
| 24 | 38 | A6D20 | strapping | adc | |
| 25 | - | LED_BUILTIN | safe | - | |
| 26 | - | SDA | safe | i2c | |
| 27 | - | SCL | safe | i2c | |
| 28 | - | D4 | safe | - | |
| 29 | - | D5 | safe | - | |
| 30 | - | D6 | safe | - | |
| 31 | - | D7 | safe | - | |
| 32 | - | D8 | safe | - | |
| 33 | - | D9 | safe | - |
Start with these
13 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
11 pins · 10 things to knowT1GPIO0 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.
TXGPIO1 Default UART0 TX pin for USB-serial programming and console. UART
Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console.
T2GPIO2 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.
RXGPIO3 Default UART0 RX pin for USB-serial programming (console input). UART
Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads.
SSGPIO5 Bootstrapping pin; internal pull-up; VSPI CS0 (default SPI chip-select); acts as FSPIWP (flash write-protect) on internal-flash variants. Strapping
Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.
MTDIGPIO12 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.
MTCKGPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
MTMSGPIO14 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.
MTDOGPIO15 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.
A7GPIO37A6GPIO38 Input-only GPIOs with ADC1 channels - no output driver Other
Cannot be used as output; only suitable for input.
- A7Input-only GPIO (no output); ADC1 channel 1.
- A6Input-only GPIO (no output); ADC1 channel 2.
The Microduino-CoreESP32 pinout brings out 33 pins at a 2.54 mm pitch - 24 usable GPIO.
For peripherals, the SPI bus (MOSI, MISO, SCK, SS) is broken out in full, while TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.
On the analog side there are 12 ADC-capable pins for sensors and battery monitoring, 10 capacitive-touch inputs and 2 true DAC outputs.
If you want zero surprises, A3, D2, D3, SCK and 9 more are free of any such role - the safest first picks. 11 of the exposed pins carry boot-time or system duties on the ESP32 (T1, TX, T2 and 8 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32 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 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:CoreESP32]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32dev - or type it after board =.esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
# 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 · 27.94 × 25.4 mm · vs other ESP32 chips →Dimensions
About this board
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
- No onboard USB - flashed by stacking a separate Microduino USBTTL (FT232R) module
Resources
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