ESP32 ESP-WROOM-32D 0.96" OLED Display
ESP32 development board with integrated 0.96" OLED display (yellow/blue) and 30 GPIO pins for compact IoT projects.
Pinout
30 pins
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 16 | OLED RSTGPIO16 | strapping | - | OLED Reset |
| 2 | 4 | OLED SDAGPIO4 | strapping | i2c | I2C Data Line for OLED |
| 3 | 15 | OLED SCLGPIO15 | strapping | i2c | I2C Clock Line for OLED |
| 4 | 0 | IO0GPIO0 | strapping | - | GPIO0, Boot Mode Selection |
| 5 | 2 | IO2GPIO2 | strapping | - | GPIO2, General Purpose I/O |
| 6 | 5 | IO5GPIO5 | strapping | - | GPIO5, General Purpose I/O |
| 7 | 12 | IO12GPIO12 | strapping | adc | GPIO12, ADC or GPIO |
| 8 | 13 | IO13GPIO13 | strapping | adc | GPIO13, ADC or GPIO |
| 9 | 14 | IO14GPIO14 | strapping | adc | GPIO14, ADC or GPIO |
| 10 | 16 | IO16GPIO16 | strapping | - | GPIO16, General Purpose I/O |
| 11 | 3 | RXD0GPIO3 | uart | uart | UART0 Receive |
| 12 | 1 | TXD0GPIO1 | uart | uart | UART0 Transmit |
| 13 | 17 | IO17GPIO17 | strapping | - | GPIO17, General Purpose I/O |
| 14 | 18 | IO18GPIO18 | safe | - | GPIO18, General Purpose I/O |
| 15 | 19 | IO19GPIO19 | safe | - | GPIO19, General Purpose I/O |
| 16 | 21 | IO21GPIO21 | safe | i2c | GPIO21, I2C SDA |
| 17 | 22 | IO22GPIO22 | safe | i2c | GPIO22, I2C SCL |
| 18 | 23 | IO23GPIO23 | safe | spi | GPIO23, SPI MOSI |
| 19 | 25 | IO25GPIO25 | safe | dac | GPIO25, DAC1 |
| 20 | 26 | IO26GPIO26 | safe | dac | GPIO26, DAC2 |
| 21 | 27 | IO27GPIO27 | safe | adc | GPIO27, ADC |
| 22 | 32 | IO32GPIO32 | safe | adc | GPIO32, ADC |
| 23 | 33 | IO33GPIO33 | safe | adc | GPIO33, ADC |
| 24 | 34 | IO34GPIO34 | strapping | adc | GPIO34, ADC Input Only |
| 25 | 35 | IO35GPIO35 | strapping | adc | GPIO35, ADC Input Only |
| 26 | - | EN | safe | - | ESP32 Enable |
| 27 | - | 3V3 | power | - | 3.3V Power Supply |
| 28 | - | GND | ground | - | Ground |
| 29 | - | VIN | power | - | 5V Input |
| 30 | - | GND | ground | - | Ground |
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
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| OLED SDA | GPIO4 | Sampled at reset for boot config; should not be driven at boot (affects boot mode timing). | Strapping |
| OLED SCL | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
| IO0 | GPIO0 | Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode. | Strapping |
| IO2 | GPIO2 | If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure. | Strapping |
| IO5 | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | Strapping |
| IO12 | 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 |
| IO13 | MTCK (GPIO13) | Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed. | Other |
| IO14 | MTMS (GPIO14) | Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot. | Other |
| IO34 | GPIO34 | Cannot be used as output (no drive capability); only suitable for analog/digital input. | Other |
| IO35 | GPIO35 | Cannot be used as output; only suitable for input. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| OLED RST | GPIO16 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | Flash |
| IO16 | GPIO16 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | Flash |
| RXD0 | U0RXD (GPIO3) | Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads. | USB |
| TXD0 | 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 |
| IO17 | GPIO17 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | Flash |
Pinout notes The ESP32 ESP-WROOM-32D 0.96" OLED Display pinout brings out 30 pins - 25 usable GPIO alongside the 3V3 , GND and VIN power rails. Beyond plain digital I/O you…
The ESP32 ESP-WROOM-32D 0.96" OLED Display pinout brings out 30 pins - 25 usable GPIO alongside the 3V3, GND and VIN power rails.
Beyond plain digital I/O you get 8 ADC-capable pins for sensors and battery monitoring and 2 true DAC outputs.
10 of the exposed pins carry boot-time or system duties on the ESP32 (OLED SDA, OLED SCL, IO0 and 7 more) - check the guidance above before wiring anything to them. IO18, IO19, IO21, IO22 and 6 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: Esp32 Dev
Flash Size: 4MB · DIO
Upload Speed: 921600
// blink
pinMode(18, OUTPUT);
digitalWrite(18, LOW); // on (often inverted)[env:esp32-wroom-32d-oled]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
# blink - GPIO18
output:
- platform: gpio
pin: 18
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binGood to know
board-specific quirks worth 60 seconds
ESP32 ESP-WROOM-32D OLED Features Built-in Display 0.96" OLED Screen: 128x64 resolution with yellow/blue color scheme I2C Interface: Connected to GPIO 21 (SDA) and GPIO 22 (SCL) Driver: SSD1306 controller for easy integration Technical Specifications Based on ESP32-WROOM-32D module with 30 GPIO pins. Perfect for projects requiring visual feedback without external display modules. Perfect For Ideal for IoT…
ESP32 ESP-WROOM-32D OLED Features
Built-in Display
- 0.96" OLED Screen: 128x64 resolution with yellow/blue color scheme
- I2C Interface: Connected to GPIO 21 (SDA) and GPIO 22 (SCL)
- Driver: SSD1306 controller for easy integration
Technical Specifications
Based on ESP32-WROOM-32D module with 30 GPIO pins. Perfect for projects requiring visual feedback without external display modules.
Perfect For
Ideal for IoT projects, sensor monitoring, status displays, and compact embedded applications where a built-in screen is advantageous.
Specifications
ESP32About this board
Inside sits the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
At $10.49 it's cheaper than most ESP32 boards, which usually run around $20.
Around the module: an OLED 0.96" 128x64 display and EN/Boot buttons.
The ESP32 ESP-WROOM-32D OLED is a compact development board featuring the ESP32-WROOM-32D module with integrated Wi-Fi 802.11 b/g/n and Bluetooth 4.2 + BLE connectivity.
Powered by a dual-core Xtensa 32-bit LX6 processor running at up to 240 MHz, with 4MB flash memory and 520KB SRAM, it's perfect for IoT applications and embedded projects.
The board features a built-in 0.96" OLED display with yellow/blue color (128x64 resolution) connected via I2C, ideal for displaying sensor data, status information, or user interfaces. It offers 30 GPIO pins with support for ADC (18 channels, 12-bit), DAC (2 channels), PWM, and various communication interfaces including UART, SPI, I2C, I2S, and CAN.
Operating at 3.3V with Micro-USB interface for programming and power. Compact design makes it suitable for space-constrained applications.
- OLED Screen
Where to buy
prices are typical street prices
Resources
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