uPesy ESP32 Wroom DevKit

General-purpose ESP32 board with WROOM module - compact and easy to integrate into embedded projects.

USB-C
uPesy ESP32 Wroom DevKit board
57.7 × 27.5 mm
ESP32
MCU
240MHz
clock
4MB
flash
520KB
SRAM
15· 4 ADC
GPIO
BLE 4.2+ WiFi
radio
On this page

uPesy ESP32 Wroom DevKit Pinout

15 pins · 2.54 mm pitch
uPesy ESP32 Wroom DevKit pinout diagram
PinGPIOLabelsStatusCapabilitiesNotes
113LED_BUILTINGPIO13strapping-Built-in LED
23IO3GPIO3uartuartUART Receive
31IO1GPIO1uartuartUART Transmit
421IO21GPIO21safei2cI2C Data Line
522IO22GPIO22safei2cI2C Clock Line
65IO5GPIO5strappingspiSPI Slave Select
723IO23GPIO23safespiSPI Master Out Slave In
819IO19GPIO19safespiSPI Master In Slave Out
918IO18GPIO18safespiSPI Clock Line
1036IO36GPIO36strappingadcADC1 Channel 0
1139IO39GPIO39strappingadcADC1 Channel 3
1232IO32GPIO32safeadcADC1 Channel 4
1333IO33GPIO33safeadcADC1 Channel 5
1425IO25GPIO25safe-Digital-to-Analog Converter 1
1526IO26GPIO26safe-Digital-to-Analog Converter 2
15 GPIOs broken out 9 free · 6 need care · 0 to avoid

Start with these

9 pins with no boot or system involvement
IO21IO22IO23IO19IO18IO32IO33IO25IO26

Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.

Fine - with a little care

6 pins · 6 things to know
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.

IO3 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.

IO1 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.

IO5 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.

IO36 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).

IO39 Input-only GPIO (no output); ADC1 channel 3, Hall sensor VN. Other

Cannot be used as output; only suitable for input.

These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.

All 15 pins on the uPesy ESP32 Wroom DevKit are usable GPIO, spaced at the standard 2.54 mm pitch.

Beyond plain digital I/O you get 4 ADC-capable pins for sensors and battery monitoring.

6 of the exposed pins carry boot-time or system duties on the ESP32 (LED_BUILTIN, IO3, IO1 and 3 more) - check the guidance above before wiring anything to them. IO21, IO22, IO23, IO19 and 5 more are free of any such role - the safest first picks.

Pinout notes The ESP32-WROOM DevKit provides a comprehensive and flexible pinout layout, making it an ideal choice for a wide range of IoT applications. The module includes…

The ESP32-WROOM DevKit provides a comprehensive and flexible pinout layout, making it an ideal choice for a wide range of IoT applications. The module includes a built-in LED connected to GPIO13, which can be easily controlled for status indicators or debugging. Communication is well-supported with dedicated pins like GPIO3 for UART receive and GPIO1 for UART transmit, ensuring seamless serial communication with other devices or computers.

For I2C communication, the board features GPIO21 for SDA and GPIO22 for SCL, allowing the connection of peripherals like sensors and displays. The SPI interface is equally robust, with GPIO23 for MOSI, GPIO19 for MISO, GPIO18 for SCK, and GPIO5 for the SS (Slave Select) line. These pins enable high-speed communication with external devices such as memory modules or other microcontrollers.

The board also supports multiple analog inputs through its ADC channels, with pins like GPIO36 (A0), GPIO39 (A3), GPIO32 (A4), and GPIO33 (A5). These pins are perfect for interfacing with sensors that provide analog output, such as temperature or light sensors. Additionally, it features two DAC outputs on GPIO25 (DAC1) and GPIO26 (DAC2), which allow for digital-to-analog signal conversion for applications like audio or waveform generation.

Getting started

flash your first firmware in ~2 minutes
Tool:
1
Connect over USB
Uses a CP2102 bridge - install the CP210x driver if no port appears. Not detected? Hold BOOT while plugging in.
2
Match & flash
Set the Tools options shown, then click Upload.
3
Verify it runs
GPIO21 toggles - wire an LED and resistor to it, or change the pin to your board's own LED.
Set these in Tools · leave everything else at default
Arduino IDE 2.x - Tools Copy
Board: "ESP32 Dev Module"▸
Flash Size: "4MB (32Mb)"▸
Flash Mode: "DIO"▸
Partition Scheme: "Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS)" (default)▸
Upload Speed: "921600"▸
▸ every other Tools option - leave at default
Board: 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
Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32 Dev Module
blink.ino Copy
// toggle GPIO21 - wire an LED and resistor to it
void setup() {
  pinMode(21, OUTPUT);
}
void loop() {
  digitalWrite(21, HIGH); delay(500);
  digitalWrite(21, LOW);  delay(500);
}
board to selectesp32dev⧉ copy
platformio.ini Copy
[env:uPesy_wroom]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600
Find it: PlatformIO Home ▸ Boards, search esp32dev - or type it after board =.
board to selectesp32dev⧉ copy
device.yaml Copy
esp32:
  board: esp32dev
  variant: esp32
  framework:
    type: esp-idf

# blink - GPIO21
output:
  - platform: gpio
    pin: 21
    id: led_out
light:
  - platform: binary
    name: "LED"
    output: led_out
Find it: search ESPHome's board list for esp32dev (same ids as PlatformIO).
esptool doesn't pick board settings - a prebuilt .bin already has them baked in. This is just the raw flash command.
terminal Copy
esptool.py --chip esp32 --port /dev/ttyACM0 \
  --baud 921600 write_flash 0x1000 firmware.bin
--port = your /dev/tty* (macOS/Linux) or COMx (Windows).
Build details: sketch space 1310720 B · data 327680 B · DIO

Specifications

ESP32 · 57.7 × 27.5 mm · vs other ESP32 chips →
Compute
MCU
ESP32
Clock
240 MHz
SRAM · Flash
520 KB · 4MB
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
4.2 LE
Antenna
PCB
I/O
GPIO · ADC
15 · 4
UART · I²C · SPI
3 · 2 · 2
PWM
16 channels
Power
USB
USB-C
Serial
CP2102
Boot address
0x1000
Electrical
Input
5V USB · 3.6-7V VIN
Consumption
-
Regulator
-
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
1.25 MB · 320 KB

Dimensions

27.5 mm57.7 mm
57.7 × 27.5 mm · pin pitch 2.54 mm
The uPesy ESP32 Wroom DevKit uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with DIO boot mode. The maximum sketch size is 1.25 MB with 320 KB available for data.

About this board

Inside sits the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.

At $15.99 it's cheaper than most ESP32 boards, which usually run around $20.

Only 15 GPIO are broken out, where most ESP32 boards manage about 24 - worth checking the pinout covers what you need.

Around the module: status LEDs (Power, User (GPIO13)) and Reset/Boot buttons.

Where to buy

prices are typical street prices
uPesy ESP32 Wroom DevKit
uPesy ESP32 Wroom DevKit
$15.99per unit, typical
As an Amazon Associate, ESPboards earns from qualifying purchases.

Resources

Similar boards