HiLetgo ESP-WROOM-32 Development Board

Development Board

Code name: ESP32_DEV

HiLetgo ESP-WROOM-32 Development Board is a development board based on the ESP32 microcontroller using XTENSA architecture.

This board features a maximum CPU frequency of 240 MHz and 4MB flash memory.

About HiLetgo ESP-WROOM-32 Development Board

The HiLetgo ESP-WROOM-32 is a compact development board based on the ESP32 microcontroller, featuring integrated 2.4GHz Wi-Fi 802.11 b/g/n and Bluetooth 4.2 + BLE for wireless connectivity. 📶

Powered by a dual-core Xtensa 32-bit LX6 processor at up to 240 MHz, with 520KB SRAM and 4MB flash memory, it's perfect for IoT projects, home automation, and embedded applications. ⚡

The board offers 38 GPIO pins with support for ADC (18 channels, 12-bit), DAC (2 channels), PWM, and various communication interfaces including UART, SPI, I2C, I2S, CAN, and Ethernet MAC. 🔌

Operating at 3.3V with Micro-USB interface for programming and power. Features an onboard LED connected to GPIO2 and supports Arduino IDE with Node32 board selection for Bluetooth functionality. 🔋

Where to Buy HiLetgo ESP-WROOM-32 Development Board

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$8.99

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Technical Specifications

Complete technical specification details for HiLetgo ESP-WROOM-32 Development Board

USB

Type Micro-USB

Serial Chip CP2102

Connectivity

WiFi 802.11 b/g/n (2.4 GHz)

Bluetooth 4.2

BLE 4.2

Microcontroller

Model esp32

Clock Speed 240 MHz

Flash Size 4MB

Architecture xtensa

✨ Features & Pins

Digital IO 30

Analog Input 16

PWM 19

Interrupts 16

Quick Setup

Copy-paste configs for HiLetgo ESP-WROOM-32 Development Board - auto‑generated from this board's exact hardware specs.

ESP32 240 MHz 4MB DIO Xtensa

In Arduino IDE 2 select Esp32 Dev from the esp32 by Espressif package. In PlatformIO use board = esp32dev. ESP32 · 240 MHz · 4MB · DIO.

Tools menu settings

Board (select in Arduino IDE) Esp32 Dev

CPU Frequency 240 MHz

Flash Size 4MB

Flash Mode DIO

Upload Speed 921600

Architecture Xtensa

In Arduino IDE 2, open Boards Manager, search "esp32" by Espressif and install it. Then go to Tools → Board and select "Esp32 Dev" for the HiLetgo ESP-WROOM-32 Development Board.

platformio.ini


[env:hiletgo-esp-wroom-32]
platform  = espressif32
board     = esp32dev
framework = arduino

; Exact hardware config for HiLetgo ESP-WROOM-32 Development Board
board_build.mcu        = esp32
board_build.f_cpu      = 240000000L
board_build.flash_size = 4MB
board_build.flash_mode = dio
board_upload.flash_size = 4MB

The board value is a close generic match - check PlatformIO board registry for an exact fit.

esp32: block (YAML)


esp32:
  board: esp32dev
  framework:
    type: arduino   # or "esp-idf"

# HiLetgo ESP-WROOM-32 Development Board - 240 MHz ESP32
# Flash: 4MB | USB: Micro-USB

Paste into your device's .yaml. See ESPHome ESP32 docs for full options.

esptool.py - flash command


esptool.py \
  --chip esp32 \
  --baud 921600 \
  write_flash \
    --flash_mode dio \
    --flash_size 4MB \
    0x1000 bootloader.bin \
    0x8000    partitions.bin \
    0xe000    boot_app0.bin \
    0x10000   firmware.bin

Install: pip install esptool - replace firmware.bin with your binary - bootloader at 0x1000

HiLetgo ESP-WROOM-32 Development Board Pinout Diagram

Complete pin reference for HiLetgo ESP-WROOM-32 Development Board

The HiLetgo ESP-WROOM-32 pinout follows the standard ESP32 DevKitC layout with 38 pins, providing extensive functionality. Power pins include 3V3 for 3.3V supply and GND for ground connection, ensuring stable power for the module.

The pinout features dedicated communication pins such as TXD0 and RXD0 for UART0, and GPIO pins from IO0 to IO39 for general-purpose I/O. ADC channels provide 12-bit analog input, DAC offers analog output, and touch sensors enable capacitive touch interfaces.

Additional pins include EN for module enable and various GPIOs configurable for SPI, I2C, PWM, and more. This versatile pinout supports digital I/O, analog functions, and multiple protocols, making it suitable for diverse IoT and embedded projects.

Safe Pins to Use

These pins are safe for general GPIO usage without boot or system conflicts

IO32

IO33

IO25

IO26

IO27

IO18

IO19

IO21

IO22

IO23

Why Are These Pins Safe?

✓ No boot sequence involvement

✓ No flash/PSRAM connections

✓ No USB or JTAG conflicts

✓ Freely assignable without issues

Pins to Avoid or Use with Caution

Reserved for critical functions. Misuse may cause boot failures, programming issues, or system conflicts.

Strapping Pins

Boot behavior & flash voltage

JTAG Debugging

Low-level debugging interface

USB Pins

USB Serial/JTAG communication

Flash/SPI Pins

Memory & PSRAM connections

UART Serial

Debugging & firmware uploads

PIN	Label	Why Avoid	Type
IO36	GPIO36 (SENSOR_VP)	Cannot be used as output; only suitable for input (e.g., analog read).	🪛 Other
IO39	GPIO39 (SENSOR_VN)	Cannot be used as output; only suitable for input.	🪛 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
IO14	MTMS (GPIO14)	Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.	🪛 Other
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
IO9	GPIO9 (Flash SD2)	Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO.	⚡ Flash
IO10	GPIO10 (Flash SD3)	Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO.	⚡ Flash
IO11	GPIO11 (Flash CMD)	Used by internal flash (chip select/command); not available for general use.	⚡ Flash
IO6	GPIO6 (Flash SCK)	Used for internal flash/PSRAM communication; not available for general GPIO.	⚡ Flash
IO7	GPIO7 (Flash SD0)	Used for internal flash/PSRAM data; not available for general GPIO.	⚡ Flash
IO8	GPIO8 (Flash SD1)	Used for internal flash/PSRAM data; not available for general GPIO.	⚡ Flash
IO15	MTDO (GPIO15)	Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.	🛠️ Strapping
IO2	GPIO2	If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.	🛠️ Strapping
IO0	GPIO0	Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.	🛠️ Strapping
IO4	GPIO4	Sampled at reset for boot config; should not be driven at boot (affects boot mode timing).	🛠️ Strapping
IO16	GPIO16	Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules.	⚡ Flash
IO17	GPIO17	Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules.	⚡ Flash
IO5	GPIO5	Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.	🛠️ Strapping

HiLetgo ESP-WROOM-32 Development Board Additional Information

More details about HiLetgo ESP-WROOM-32 Development Board

HiLetgo ESP-WROOM-32 Compatibility

🔌 Arduino IDE Setup

Board Selection: Use "Node32" for Bluetooth functionality, or "ESP32 Dev Module" for standard operation
Built-in LED: Connected to GPIO2 - use digitalWrite(2, HIGH) to control
Upload Speed: Supports high-speed uploads up to 921,600 baud

⚙️ Technical Specifications

Based on ESP32-WROOM-32 module with TSMC 40nm ultra-low power technology. Supports AP, STA, and AP+STA modes for WiFi connectivity.

💡 Getting Started

Connect via Micro-USB, install ESP32 board support in Arduino IDE, and start developing IoT applications with built-in WiFi and Bluetooth capabilities.

Useful Links

Datasheets and resources for HiLetgo ESP-WROOM-32 Development Board

ESP32 Datasheet

Microcontroller reference

HiLetgo ESP-WROOM-32 Fritzing

https://forum.fritzing.org/uploads/default/original/2X/4/468d28b00e60cba3bc483139896d7a7d38db4eaa.fz

HiLetgo ESP-WROOM-32 Development Board Custom Pin Mapping

Pin configuration and GPIO mapping for HiLetgo ESP-WROOM-32 Development Board

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Function	ESP Pin	I/O Type	Description
2	IO36	GPIO36	INPUT	ADC1_CH0, GPIO36
3	IO39	GPIO39	INPUT	ADC1_CH3, GPIO39
4	IO34	GPIO34	INPUT	ADC1_CH6, GPIO34
5	IO35	GPIO35	INPUT	ADC1_CH7, GPIO35
6	IO32	GPIO32	BIDIRECTIONAL	ADC1_CH4, GPIO32
7	IO33	GPIO33	BIDIRECTIONAL	ADC1_CH5, GPIO33
8	IO25	GPIO25	BIDIRECTIONAL	DAC1, ADC2_CH8, GPIO25
9	IO26	GPIO26	BIDIRECTIONAL	DAC2, ADC2_CH9, GPIO26
10	IO27	GPIO27	BIDIRECTIONAL	ADC2_CH7, GPIO27
11	IO14	GPIO14	BIDIRECTIONAL	ADC2_CH6, GPIO14
12	IO12	GPIO12	BIDIRECTIONAL	ADC2_CH5, GPIO12
13	GND	GND	POWER	Ground
14	IO13	GPIO13	BIDIRECTIONAL	ADC2_CH4, GPIO13
15	IO9	GPIO9	BIDIRECTIONAL	SD_DATA2, GPIO9
16	IO10	GPIO10	BIDIRECTIONAL	SD_DATA3, GPIO10
17	IO11	GPIO11	BIDIRECTIONAL	SD_CMD, GPIO11
18	IO6	GPIO6	BIDIRECTIONAL	SD_CLK, GPIO6
19	IO7	GPIO7	BIDIRECTIONAL	SD_DATA0, GPIO7
20	IO8	GPIO8	BIDIRECTIONAL	SD_DATA1, GPIO8
21	IO15	GPIO15	BIDIRECTIONAL	ADC2_CH3, GPIO15
22	IO2	GPIO2	BIDIRECTIONAL	ADC2_CH2, GPIO2, LED
23	IO0	GPIO0	BIDIRECTIONAL	ADC2_CH1, GPIO0, BOOT
24	IO4	GPIO4	BIDIRECTIONAL	ADC2_CH0, GPIO4
25	IO16	GPIO16	BIDIRECTIONAL	GPIO16
26	IO17	GPIO17	BIDIRECTIONAL	GPIO17
27	IO5	GPIO5	BIDIRECTIONAL	GPIO5
28	IO18	GPIO18	BIDIRECTIONAL	GPIO18
29	IO19	GPIO19	BIDIRECTIONAL	GPIO19
31	IO21	GPIO21	BIDIRECTIONAL	GPIO21
32	RX	GPIO3	INPUT	UART0 Receive
33	TX	GPIO1	OUTPUT	UART0 Transmit
34	IO22	GPIO22	BIDIRECTIONAL	GPIO22
35	IO23	GPIO23	BIDIRECTIONAL	GPIO23

Legend

Function Pin role

GPIO ESP32 pin

I/O Direction

# Pin number

Pin Mappings

Complete pinout and GPIO mapping for HiLetgo ESP-WROOM-32 Development Board

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Analog	Touch	PWM	Other
0		T1
1			PWM	TX
2	A12	T2	PWM
3			PWM	RX
4	A10	T0	PWM
5			PWM
12	A15	T5	PWM
13	A14	T4	PWM
14	A16	T6	PWM
15	A13	T3	PWM
16			PWM
17			PWM
18			PWM
19			PWM
21			PWM	SDA
22			PWM	SCL
23			PWM	MOSI
25	A18			DAC1
26	A19			DAC2
27	A17	T8	PWM
32	A4	T9	PWM
33	A5	T10	PWM
34	A6			INPUT
35	A7			INPUT

Legend

A0 Analog input

T0 Touch sensor

PWM PWM capable

RX/TX Serial pins

LED Built-in LED

# Pin number

Default Tools & Configuration

Build and upload settings for HiLetgo ESP-WROOM-32 Development Board

Setting	Value
Bootloader tool	esptool_py
Uploader tool	esptool_py
Network uploader tool	esp_ota
Bootloader address	`0x1000`
Flash mode	dio
Boot mode	dio
Maximum upload size	1280 KB (1310720 bytes)
Maximum data size	320 KB (327680 bytes)

Configuration Summary

The HiLetgo ESP-WROOM-32 Development Board uses esptool_py for uploads , esp_ota for OTA updates, and esptool_py bootloader at 0x1000.

Flash mode: dio | Boot mode: dio

Max sketch size: 1280 KB | Max data size: 320 KB