Heltec WiFi LoRa 32

Development Board

Code name: heltec_wifi_lora_32

ESP32

Heltec WiFi LoRa 32 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 Heltec WiFi LoRa 32

ESP32 with built-in OLED and LoRa - perfect for long-range IoT applications and remote sensing.

Technical Specifications

Complete technical specification details for Heltec WiFi LoRa 32

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 40

Analog Input 16

PWM 19

Interrupts 16

Download Full Datasheet

Quick Setup

Copy-paste configs for Heltec WiFi LoRa 32 - auto‑generated from this board's exact hardware specs.

ESP32 240 MHz 4MB DIO Xtensa

In Arduino IDE 2 select Heltec Wifi Lora 32 from the esp32 by Espressif package. In PlatformIO use board = esp32dev. ESP32 · 240 MHz · 4MB · DIO.

Tools menu settings

Board (select in Arduino IDE) Heltec Wifi Lora 32

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 "Heltec Wifi Lora 32" for the Heltec WiFi LoRa 32.

platformio.ini


[env:heltec_wifi_lora_32]
platform  = espressif32
board     = esp32dev
framework = arduino

; Exact hardware config for Heltec WiFi LoRa 32
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"

# Heltec WiFi LoRa 32 - 240 MHz ESP32
# Flash: 4MB | USB: N/A

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

Heltec WiFi LoRa 32 Pinout Diagram

Complete pin reference for Heltec WiFi LoRa 32

Useful Links

Datasheets and resources for Heltec WiFi LoRa 32

Board Datasheet

Technical specifications

ESP32 Datasheet

Microcontroller reference

Pin Mappings

Complete pinout and GPIO mapping for Heltec WiFi LoRa 32

Digital I/O Pins

Interrupt Pins

Analog Inputs

PWM Pins

Pin	Analog	Touch	PWM	Other
0	A11	T1		KEY_BUILTIN
1			PWM	TX
2	A12	T2	PWM
3			PWM	RX
4	A10	T0	PWM	SDA_OLED
5			PWM	SCK
12	A15	T5	PWM
13	A14	T4	PWM
14	A16	T6	PWM	RST_LoRa
15	A13	T3	PWM	SCL_OLED
16			PWM	RST_OLED
18			PWM	SS
19			PWM	MISO
21			PWM	SDA Vext
22			PWM	SCL
25	A18		PWM	LED_BUILTIN DAC1 LED
26	A19		PWM	DAC2 DIO0
27	A17	T7	PWM	MOSI
32	A4	T9	PWM	DIO2
33	A5	T8	PWM	DIO1
34	A6
35	A7
36	A0
39	A3

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 Heltec WiFi LoRa 32

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)