ESP32-WROOM-32U DevkitC V4 is a Wi‑Fi/Bluetooth development board for building embedded projects, commonly programmed with the Arduino/ESP32 toolchain. It provides standard digital GPIO plus serial interfaces such as UART (TXD0/RXD0), I2C (SDA/SCL), and SPI (MOSI/MISO/SCK with a chip-select pin). The board also exposes analog-capable pins and uses on-board power rails (3.3V and 5V) for typical wiring.
| Pin | Signal | Description |
|---|---|---|
GND |
ground | Ground reference for power and signals. |
GPIO23 |
MOSI | ESP32 GPIO23; general I/O, commonly used as VSPI MOSI. |
GPIO22 |
SCL | ESP32 GPIO22; general I/O, commonly used as I2C SCL. |
TXD0 |
TX | UART0 transmit from ESP32, also used for serial programming/log output. |
RXD0 |
RX | UART0 receive to ESP32, also used for serial programming. |
GPIO21 |
SDA | ESP32 GPIO21; general I/O, commonly used as I2C SDA. |
GND.1 |
ground | Ground reference for power and signals. |
GPIO19 |
MISO | ESP32 GPIO19; general I/O, commonly used as VSPI MISO. |
GPIO18 |
SCK | ESP32 GPIO18; general I/O, commonly used as VSPI SCK. |
GPIO5 |
chip-select | ESP32 GPIO5; general I/O, common SPI chip-select and boot strapping pin. |
GPIO17 |
digital | ESP32 GPIO17; general-purpose digital I/O with UART/PWM capability. |
GPIO16 |
digital | ESP32 GPIO16; general-purpose digital I/O with UART/PWM capability. |
GPIO4 |
digital | ESP32 GPIO4; general I/O, ADC-capable touch/boot strapping pin. |
GPIO0 |
digital | Boot strapping GPIO; hold low during reset to enter firmware download mode. |
GPIO2 |
digital | ESP32 GPIO2; general I/O and boot strapping pin, often connected to onboard LED on some boards. |
GPIO15 |
digital | ESP32 GPIO15; general I/O, ADC-capable touch/boot strapping pin. |
SD1 |
data | SPI flash data pin SD1; normally used by onboard flash, avoid for external circuits. |
SD0 |
data | SPI flash data pin SD0; normally used by onboard flash, avoid for external circuits. |
CLK |
clock | SPI flash clock pin; normally used by onboard flash, avoid for external circuits. |
3V3 |
power-low | Regulated 3.3 V output rail for ESP32 logic and low-current peripherals. |
EN |
enable | Chip enable/reset input; pull low to reset ESP32, high to run. |
VP |
analog | GPIO36/SENSOR_VP; input-only ADC1 analog input. |
VN |
analog | GPIO39/SENSOR_VN; input-only ADC1 analog input. |
GPIO34 |
analog | Input-only ESP32 GPIO34; ADC1 analog input, no output drive. |
GPIO35 |
analog | Input-only ESP32 GPIO35; ADC1 analog input, no output drive. |
GPIO32 |
analog | ESP32 GPIO32; general I/O with ADC1, touch and PWM capability. |
GPIO33 |
analog | ESP32 GPIO33; general I/O with ADC1, touch and PWM capability. |
GPIO25 |
analog | ESP32 GPIO25; general I/O with ADC2 and DAC output capability. |
GPIO26 |
analog | ESP32 GPIO26; general I/O with ADC2 and DAC output capability. |
GPIO27 |
analog | ESP32 GPIO27; general I/O with ADC2, touch and PWM capability. |
GPIO14 |
SCK | ESP32 GPIO14; general I/O, ADC2-capable, commonly usable as SPI clock. |
GPIO12 |
digital | ESP32 GPIO12; general I/O and boot strapping pin, use with care at reset. |
GND.2 |
ground | Ground reference for power and signals. |
GPIO13 |
digital | ESP32 GPIO13; general I/O with ADC2, touch and PWM capability. |
SD2 |
data | SPI flash data pin SD2; normally used by onboard flash, avoid for external circuits. |
SD3 |
data | SPI flash data pin SD3; normally used by onboard flash, avoid for external circuits. |
GND.3 |
ground | Ground reference for power and signals. |
5V |
power | 5 V supply rail from USB/VIN area; can power 5 V peripherals within board limits. |
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